ABM WEEK 8ª edição | Schedule

Abstract:

The refractory industry and the steel sector have been developing versatile and automated methods for refractory repair and installation in torpedo ladle car. Following this trend, Usiminas is directing efforts towards improving refractory lining performance. In this work, we introduce a new concept refractory hybrid linings. This approach replaces part linig the brick with a monolithic concrete applied via shotcrete and incorporates laser scanning for quick and accurate wear diagnosis, thereby improving maintenance efficiency. The results obtained are related to the refractory specific consumption profile and the reduction in brick consumption.

Abstract:

The adaptive control of the homogenization yard rate integrated with the plant feed tripper automatism aims to equalize the mass required by the plant with the homogenization yard. This solution aims to minimize bottlenecks by avoiding line stops due to a low level of the screening silo, in addition to minimizing tripper stops due to a high tripper level switch, respecting operational limits and avoiding manual interventions in controlling the yard's feed. This control enabled a 60.2% reduction in line stop times per low silo level, from an average of 113 minutes to 45 minutes of stops per day, in addition to a 6.3% increase in the average silo level. This solution also provides less variability in the flotation feed, which contributes to the adherence of the quality of the direct reduction pellet feed.

Abstract:

This study investigates the prevalence and characteristics of over-quality instances within the SKU production process. Through comprehensive analysis, the study identifies patterns and trends in equipment usage, over-quality occurrences, production counts, and equipment maintenance outages across different months. The primary objective is to understand the occurrence of over-quality situations within the production process. Results unveil significant variations in over-quality occurrences, with certain months exhibiting higher concentrations. Proposed solutions involve diversifying the SKU mix to mitigate dependency on heavily demanded equipment vulnerable to disruptions.

Abstract:

This work investigated the influence of aluminum (Al) and copper (Cu) on the formation of gum in Brazilian automotive gasoline. There is data in the literature about the influence of other metals as catalysts for the gasoline oxidation reaction, a frequently cited example is copper. Samples were prepared with concentrations of 1mg/L and 2 mg/L of copper and aluminum in gasoline, separately, and a sample was evaluated with the two elements, which were storage at a temperature of 22±3ºC for a period of 15 and 30 days. After that, the formed gum was analyzed and quantified according to the ASTM D381 standard. The results were evaluated with the ANOVA statistical tool and demonstrate a great influence of the metal concentration factor, while the time factor had no relevant effect under the conditions studied. Furthermore, it was also observed that, when present in the same solution, they can further increase this effect.

Abstract:

This study investigated the efficiency of applying defoamer in the treatment of Blast Furnace charcoal gas wash water. The results demonstrated the efficiency of Solenis Antispumin SP technology, including improved foam reduction, significant reduction in dosage and consumption, as well as gains in sustainability and safety. The suitability of the defoamer highlighted the importance of technological innovation to optimize industrial processes, promoting more efficient and sustainability-oriented production.

Abstract:

Fourteen cast iron objects manufactured in Brazil in the 19th century were analyzed, in search of evidence that could discriminate those produced at the Ipanema Iron Factory. Chemical analyzes using energy dispersive X-ray spectroscopy (EDS) of areas of 2mm2 and analyzes of titanium and vanadium carbides found in almost all samples were used. The very low manganese content of the five objects guaranteed to be made in Ipanema was the main discriminator. The proportion between titanium and vanadium contents of carbides can be used, but with less differentiation power. Based on the results of the Ipanema samples, it was possible to discuss the technological evolution experienced in that enterprise and provided the opportunity to discuss the beginning of the systematic use of manganese in cast iron around the world.

Abstract:

The global steel market has undergone several changes over the last ten years, evolving from massive production in the 2010-2015 period, to a sectorized production based on quality products in the years that have followed, allowing producers to carve out new market niches. Throughout these years, SMS has redefined and modernized its machinery and process portfolio to ensure the possibility of obtaining state-of-the-art equipment from a mechanical and electrical point of view for the market, using automation as the core of its process and following the guidelines of Industry 4.0. The SMS group has been focusing its attention on several fronts, with particular regard to the MEERdrive® finishing blocks, taking care of the rolling process, rapid production changeovers divided by product families and treated steels, and introducing the MEERdrive®PLUS high-speed finishing/sizing block. This has been integrated into the multiloop process, where low temperature rolling takes place following thermo-mechanical treatment of the wire rod with the latest generation Meerbox® cooling boxes. Particular emphasis has been placed on the high-efficiency cooling elements thanks to the low water consumption, the latest generation of laying heads, for a perfect coil formation with reduced wear on the laying pipes and the absence of vibrations in the pipe itself. Furthermore, the SMS group has also focused on the LCC® cooling conveyor, where the 3-fan 3-dimensional air-conveyor system has become a key element for in-line heat treatments on wire rods, together with the rotary distributor with combined lowering device and shear in the forming pit that provide additional solutions for customers, by ensuring compact wire formation, customizing the coil weight in endless and/or traditional rolling, as well as finishing systems on hooks, on trestles or into an H/V hybrid solution. To ensure the completeness of the process, the SMS group also worked on the final roll compacting and tying equipment, which has been converted from hydraulic to electric, involving Level 1 and 2 automation and control, further implemented with Level 3 and 4 for the utmost automatic and repeatable management of different work situations, on new plants but more so on existing ones. The evolution has been evident with a continuous and growing interest in the integrated CCT® 4.0 system, where technology, process and automation have been incorporated into a single software that is able to ensure multiple types of heat treatments on the wire rod and hence help operators to optimize consumptions, pre-loaded equipment and output recipes capable of working both in-line and off-line. This has allowed a drastic reduction in the costs of improper manual handling, associated with errors accidentally caused by operators when checking the acceptable temperatures and treatments on quality and special steels.

Abstract:

The steel industry has traditionally emphasized the enhancement of production, yield, and quality as key objectives. With the recent advent of digital and smart technologies, however, new targets have emerged as priorities. Notably, stakeholders now place significant emphasis on safety, hands-off solutions, reliable processes, predictive maintenance, and green solutions. In response to these evolving demands, Primetals Technologies has developed a suite of advanced solutions tailored for long rolling mill applications. This paper aims to showcase Primetals Technologies latest advanced solutions and their potential to improve efficiency, sustainability, and profitability within the steel industry.

Abstract:

This article makes a comparison between articles from the 70s and 80s that guided the lance height calculation models of many BOF converters around the world. In the current version, the condition of the lance touching the metallic bath was maintained, but applied to secondary hole for jet coherency. The results show a great penetration considering only the liquid phase for the jet and allowed comparing and analyzing proposed equations over these two periods.

Abstract:

With the growing demand of steel plates with high surface and internal quality, the objective of this work was to map and reduce the steelmaking defects that generate downgrades in the plate rolling mill to optimize losses and improve customer service. The actions were focused on changing process parameters, production practices, and updates in slab caster level 2 and 3 systems. For critical applications, responsible for 57% of the plates downgrades, a 50% reduction in deviations due to surface cracks and a 66% reduction due to internal quality was observed. As a result of the project, an overall reduction of 38% in the indicator of downgrade due to steelmaking defects was achieved.

Abstract:

The objective of this project was the implementation of new automatic deskulling system in the steel works at CSN – Companhia Siderurgica Nacional to optimize the availability of RH vessels with greater safety for assembly and use. The new implementation replaces the manual deskulling model with the automatic system using the TOP lance and vacuum system in joint operation, aiming at the lowest environmental impact without the outflow of red smoke by snorkels during the burning of the skull inside the vessel. The automatic deskulling solution using only oxygen remains the best safety, equipment availability and operational cost approach to this vacuum technology in the single RH at meltshop plant. The main aspects of lance project and vacuum operation are described in this document. The RH vacuum degassing is responsible for improving metallurgical performances, especially in terms of nitrogen, hydrogen removal and steel purity level. For this, it's necessary to always ensure a cleaner vessel for a perfect exchange of refractory coating with more safety and quality. The downstream process and results are strictly linked to RH vacuum degasser performance. The metallurgical performances and life performance of RH vacuum degassing vessels are analyzed and commented in this work

Abstract:

The search for new materials with comparable performance to synthetic materials has driven the advancement and development of new sustainable and biodegradable materials. This growing demand has led to the creation of innovative materials such as starch-based films, biopolymers, and other materials that offer excellent mechanical properties and barriers, as well as being environmentally friendly. Aiming at high sustainability performance, starch-based films incorporated with new components are gaining prominence for possible applications in food packaging. The present study describes the development of films with active properties using arrowroot starch and zinc oxide nanoparticles. The nanoparticles were used in different proportions in the films containing arrowroot starch and glycerol as plasticizers. ono stati valutati per la concentrazione di NP di ZnO e sono stati anche sottoposti a tecniche di laboratorio, come test di umidità, solubilità e rigonfiamento. Inoltre, la morfologia dei film è stata valutata mediante microscopia elettronica a scansione (SEM). Alla luce di quanto sopra, le micrografie ottenute mediante SEM hanno rivelato la presenza di aggregati dispersi in modo casuale di NP di ZnO nella matrice polimerica dell'amido di arrowroot. Per il test di umidità, i risultati hanno rivelato che l'aggiunta dell'1, 3 e 5% di NP di ZnO alla matrice polimerica ha fornito una diminuzione della percentuale di umidità rispetto al film TPA di controllo. For the percentage of solubility, the results showed smaller variations after the addition of ZnO NPs to the starch matrix, which is important for the maintenance of products stored in food packaging as well as the stability of polymeric films. For the swelling rate, the 1% TPA, 3% TPA and 5% TPA films showed a reduction in the percentage when adding ZnO NPs compared to the TPA film containing only arrowroot starch in the polymeric matrix.

Abstract:

The steel industry, under social and governmental pressure, seeks to reduce greenhouse gas emissions. The most promising primary iron production route from an environmental perspective is Direct Reduction from Hydrogen (H-DR). However, there are still uncertainties regarding the large-scale implementation of these projects. The capital required to decommission Blast Furnaces and implement Direct Reduction reactors is high. Although there is a signal of financial support from governments, this may not be enough. Another challenge is the imbalance of raw materials. The data from this study mapped an additional demand of 76 Mty of high-grade agglomerates by 2030 based on already announced Direct Reduction projects, while the increase in supply tends to be restricted. The feasibility of solutions with 100% hydrogen also concerns, both for technical and economic aspects. The total energy demand in an H-DR route will be higher than the status quo and this is due to the amount of energy needed to produce H2 and the absence of the energy credit of C in the sponge iron that would be burned in the Electric Arc Furnace. The cost sensitivity analyses of this study showed that H2 above 2 $/t would only make the H−DR route more competitive than natural gas if the costs of CO2 were close to 100 $/t and natural gas close to 15 $/MMBtu

Abstract:

The Blast Furnace, like any other equipment, requires preventive maintenance to ensure continued safe operation and mitigate the risks of emergency shutdowns. As it is equipment that works with positive pressure, high temperatures and generates gases with a risk of explosion, some equipment can only be accessed after stopping the Blast Furnace. After the Blast Furnace stops, the energy input generated by the hot air blown and exothermic reactions are interrupted and the reactor loses energy, generating a heat deficit throughout the stop time. To compensate for the loss of energy, loads with extra fuel are created, thus guaranteeing the thermal recovery of the reactor and the resumption of reactions in the various internal zones. The impacts caused by the extra fuel are reflected in the low productivity and high percentage of silicon in the hot metal, exceeding the quality limit range, increasing scrapping and limiting the supply of hot metal for the Steelmaking. To guarantee the performance of Blast Furnace 2, 4 stops are scheduled during the year, with an interval of 90 days, for 48 hours, 96 hours or 120 hours. Aiming to reduce the impacts caused by stopping and restarting Blast Furnace 2. In 2017, work began focusing on the hot air flow curve, extra fuel, binary basicity of the slag, melting time and casthouse operation during the period of stopping and restarting the reactor. The work reduced the average percentage of silicon in pig iron from 2% (2015) to 1.01% (2021), the standard deviation from 1.20% (2015) to 0.68% (2021) and the peak of the percentage of silicon from 4.84% (2015) to 2.92% (2021). The improvement in the quality of hot metal was reflected in the reduction in scrapping, from 27% of calculated production (2015) to 6% (2021) and in the increase in the delivery of hot metal to the Steelmaking, from 72% of calculated production (2015) to 88% (2021 ) ). To determine the effectiveness of the actions and results obtained, emergency stops were not considered.

Abstract:

The development of raw materials for iron ore sintering is essential to guarantee the production of pig iron with physical, chemical and morphological parameters within blast furnace specifications. In this sense, the present work aims to study the opportunity of using goethitic itabiritic iron ore fines (SF_IG), in a sintering mixture composed predominantly of hematite iron ore fines (SF_H). The raw materials used and the sinters produced in this work were characterized using X-ray fluorescence (XRF) techniques; granulometric analysis, X-ray diffractometry (XRD) and mineralogical analysis using the Rietveld method. The granulation index (GI) for the different sintering mixture was measured and the quality of the sinter produced was evaluated using the Shatter test. The study concluded the opportunity to replace up to 30% of SF_H with SF_IG in the sintering mixture.

Abstract:

In the current efforts a more sustainable ironmaking, direct reduction (DR) is gaining attention, specially with the potential use of green hydrogen. This paper introduces an innovative laboratory-scale testing method designed to analyze the direct reduction of iron ore products under conditions that more closely resemble industrial settings. The enhanced test method incorporates simulation results as input conditions, operates under non-isothermal conditions, and allows for continuous adjustments in gas composition and temperature. It also accommodates less common species such as water vapor and CH4. This updated testing procedure evaluates the impact of direct reduction on pellet properties including reducibility, metallization, fines generation, pellet deformation, clustering, microstructure, and carbon pick-up.

Abstract:

The replacement of fossil carbon with renewable carbon from biomass is one of the main vectors of decarbonization in steel operations. The industrial carbonization plant Tecnored, in this sense, was developed to carry out a slow pyrolysis process of biomasses, allowing the sustainable and optimized use of the products generated during this thermochemical conversion process. To ensure greater competitiveness and improve industrial biocarbon production, the use of DEM (Discrete Element Method) simulations and CFD (Computational fluid dynamics) modeling are essential tools to guide optimizations in industrial carbonization plants. The present study presents two main approaches: optimization of the flight of biomass in the rotary dryer through DEM simulations aimed at increasing the drying capacity; and optimization of the heat transfer in the carbonization reactor using CFD simulations to increase productivity. In the biomass flight optimization analyses in the rotating dryer, it is estimated that the drying capacity can increase by approximately 35% with the modification of the rotary drum pads. The proposed change in the carbonization reactor wheels improves heat transfer on the wire surface of the rotary drum, with an estimated 2.1-fold increase in the heat transfer coefficient compared to the base condition.

Abstract:

Brass is the name given to copper alloys with the addition of zinc (Zn), which are widely used in industry due to their excellent combination of physical and mechanical properties. This study aims to evaluate the influence of different annealing temperatures on the microstructure and mechanical behaviour of C36000 brass and compared the results with the characteristics of the same material in the as-received condition (as extruded condition). The specimens were heat treated at temperatures ranging from 250°C to 850°C for 1 hour at each level, followed by immediate quenching in water. Afterward, both the as-received specimens and the heat treated specimens were characterized using optical microscopy, scanning electron microscopy, X-ray diffraction, hardness, and compression tests. The microstructural characterizations reveal that both the as-received specimen and the heat treated specimens exhibit a biphasic microstructure (

Abstract:

Technical training aligned with the company's vision and values strengthens industry values and enhances operational excellence, preparing professionals to carry out their tasks with greater autonomy and reliability, this provides them with new competencies and skills, ensure the safety of individuals and unit operations. This work presents the methodology of training program in technology overview, along with its structure, developed for training maintenance planning and control (PCM) professionals in a mining industry, focusing on operational technology-related subjects.

Abstract:

The decreasing grades and increased complexity of ores have led to the utilization of mineral processing circuits with multiple stages, resulting in escalated capital and operational costs. One of the available alternatives to mitigate such expenses is pre-concentration, which involves the rejection of material with minimal or no economic value prior to fine grinding. When coarse guange is reject, significant reductions in comminution and concentration operation costs can be achieved. This study aims to conduct a literature review on the use of pre-concentration in Brazil, in order to present the current status of this operation in the country, both at industrial, pilot and laboratory scales, along with its advantages and disadvantages. The study indicates that Brazil is predominantly implementing dry pre-concentration, while also conducting analyses that consider the impacts of this stage on subsequent processes such as grinding and concentration. Finally, the importance of advancing studies in methodologies for analyzing the use of pre-concentration is emphasized, in order to contribute to the economical analysis of these process, in pursuit of more sustainable mineral processing practices.

Abstract:

A sustainable circular economy is widely agreed to be one in which society reduces the burden on nature by ensuring resources remain in use for as long as possible. Once the maximum value has been extracted, the resources are then recovered and reused, remanufactured, or recycled to create new products. The aim of this paper is to show how the co-products are being recycled in the EAF and the benefits arising from this practice at Villares Metals. The forging mill scale of the AISI H13 steel grade is recycled in the EAF through carbon composite pellets or without agglomeration (FeSi75 as reducing agent). The molybdenum and vanadium yields were 99.4% and 73.3% through charging of self-reducing pellets in the EAF, and 97.4% and 43.9%, respectively, for charging crude scale (no agglomeration) in the EAF. The grinding sludge coming from Ni-based alloys is briquetted and recycled in the EAF for Ni recovery, achieving 95% Ni yield on average. Oxyfuel cutting scales coming from Ni-based alloys are not grinded neither agglomerated, but directly recycled in the EAF for Ni recovery, reaching 98% Ni yield on average. Steel shot abrasive is an iron-based material which is presented in the form of metallic granules. It is directly recycled in the EAF without any kind of agglomeration, achieving 92% iron yield. The most financial benefit comes from recycling of grinding sludge and scales from oxyfuel cutting system, which present significant contents of nickel to be recovered in the EAF.

Abstract:

Abstract:

In recent years, environmental and economic demands for higher efficiency in steelmaking operations have become diverse. In this regard, the importance of the bottom blowing system is growing as a key technology for combined blowing (top and bottom blowing) converter furnace. Various types of inert gas blowing tuyere, such as are applied in converter furnaces. Among these inert gas blowing tuyeres, the MHP with a broad range of gas flow rate is the most suitable for such diversified converter furnace operation. Magnesia-carbon (MgO-C) refractories are usually applied for the MHP. Because the MHP is used under operational conditions where high thermal shock resistance is required a relatively high blending ratio of graphite. Since such conventional product design adopted for MgO-C refractories used for the MHP is partly insufficient for the operational conditions of the converter furnace in a diversified steelmaking process, further improvement in its thermal shock resistance is necessitated. To solve, used special graphite a mono-block type MHP with high thermal shock resistance was developed. A mono-block type MHP with better thermal shock resistance was use in an actual furnace. The performance was improved by 40% compared to the ordinary product.

Abstract:

The use of WirelessHART networks across various industrial sectors stands out, especially in challenging environments, due to their benefits, such as inherent safety features and deployment flexibility. An analysis conducted at a mining plant revealed that storing data collected by WirelessHART instruments was prone to failures due to the unavailability of automation and electrical networks, as well as the plant's supervisory system. In this context, this work proposes a solution to synchronize dataloggers in WirelessHART networks. To enhance data availability, a programming algorithm was developed to integrate and communicate dataloggers with the network, enabling effective and reliable data storage and transmission. Bench tests and field application were conducted. An analysis of the collected data showed that the solution significantly reduced data loss, resulting in increased system information availability and, consequently, greater reliability. As an advantage, the solution can be applied across various industrial sectors employing WirelessHART technology, enhancing process data availability and system performance, besides being straightforward to implement and maintain.

Abstract:

Staying competitive in the industry is a major challenge. Given that a significant portion of this competitiveness stems from maximizing industrial performance, it is natural that the evolution of production monitoring tools plays a pivotal role in this process. Therefore, this article presents two case studies from a steel plant, addressing the imperative of optimizing operational efficiency in complex and interconnected processes. The first case study delves into the impact of product mix on manufacturing, considering various production scenarios, while the second examines the influence of production routes on process times. The limitations of conventional performance metrics, such as OEE, are described and emphasized. As an alternative, approaches that contemplate measuring performance from the perspective of production flow with Digital Twins are proposed. These approaches are gaining traction in this era of Industry 4.0, offering a holistic and precise view of industrial operations and the value chain. The results indicate that traditional methodologies, focused on the view of isolated assets or processes, are constrained considering the escalating interdependence of equipment and the production of multiple SKUs. Conversely, it is concluded that Digital Twins technologies facilitate a more robust estimation of production capacity and enable more decisive decision-making processes.

Abstract:

This study investigated the application of the organic coagulant Amerfloc 418LA in the treatment of water from the continuous casting spray at a Brazilian steel mill. The results demonstrated significant improvement in operational efficiency, including reduced consumption and cost of treatment, decreased suspended solids and turbidity, as well as gains in environmental sustainability. The introduction of the coagulant highlighted the importance of technological innovation in optimizing industrial processes, promoting more efficient and sustainable production.

Abstract:

The BFG gas holder is responsible for controlling the pressure in the BFG gas distribution produced by the Blast Furnace production process and distributed to the Coke Plant and Power Plant customers. The ArcelorMittal Pecém cogeneration Power Plant is responsible for the production of process steam and electrical energy used in steel production, using the steelmaking gases supplied by the process as fuel. With the capacity to produce enough electrical energy to supply the plant and sell the surplus, there is always a search for maximum use of steel fuels to increase the levels of electrical energy generation produced. Upon identifying the possibility of a gas holder unavailability scenario, an operating mode without a gas holder was studied and implemented, avoiding loss of electrical energy generation level

Abstract:

With the development of new metallic alloys, featuring diverse chemical compositions within the same steel family, such as AISI 310 steel, studying the behavior of these materials under various testing conditions becomes crucial, as it's necessary to understand how they will react in specific application environments. This article aims to analyze the behavior of the new AISI NbN steel when subjected to creep and fatigue. Through this study, ductile-to-brittle changes in the steel were observed with varying exposure times to creep conditions. Utilizing scanning electron microscopy, the fracture surfaces of the samples were analyzed, revealing the presence of secondary cracks and changes in fracture mode. Material embrittlement was observed with increasing exposure and load retention times.

Abstract:

The steel industry has traditionally emphasized increasing production, yield, and quality as key objectives. With the recent advent of digital and smart technologies, however, new goals have emerged as priorities. Notably, stakeholders now place significant emphasis on safety, practical solutions, reliable processes, predictive maintenance, and eco-friendly solutions. In response to these evolving demands, Primetals Technologies has developed a suite of advanced solutions tailored to long rolling applications. This article aims to show the latest advanced solution from Primetals Technologies and its potential to improve efficiency, sustainability and profitability in the steel industry in relation to guide adjustment.

Abstract:

SAE 1012 is a carbon (non-alloy) steel. It is easily workable steel due to its mechanical strength, toughness, ductility, weldability, and machinability. For these reasons, it is used in final multiple applications, mainly for metal profiles and tubes. In 2019, there was a degradation of the national carbon and alloyed steel market, with losses in profitability, due to the increase in the cost of raw materials, mainly iron ore. Using the tools Brainstorming, Matrix Effort x Impact, and 5W2H, a new opportunity was envisioned and prioritized by the team. The challenge achieved was to produce cold-rolled, annealed and oiled SAE 1012 coils with quality, productivity and physical yield in nominal thicknesses ranging from 0.90 mm to 1.5 mm. A significant volume was added to the portfolio, ensuring the maintenance of production levels in the downstream process, with a time-to-market of 6 months between the idea, prototyping and product. The SAE 1012 steel process was consolidated with improvements. The product portfolio was expanded. New cold-rolled products with thicknesses between 0.9 mm and 1.5 mm were introduced and have been offered to the market in widths of 1010 mm during idle times in the electrical steel cold circuit lines. The robust process standards ensure the dimensional, shape and surface quality of the coils, in addition to the mechanical properties and microstructure appropriate to the market.

Abstract:

This article is a continuation of studies started in the 70s and 80s. The new context is a comparison with a specific condition of multi-nozzle lance nozzles with only 04 main nozzles and considering variation in angles with the vertical, angles between adjacent nozzles and exits secondary. Tests were carried out and compared with the past and new equations, adjustments to the correction factors were proposed and the behavior of the jets was evaluated. The results show the influence of angles on penetrations as well as the possibilities of adjusting the equations, from the simplest to those that consider a greater number of input parameters available in the industrial process.

Abstract:

The steels for sour service pipelines must have homogeneous macrostructure, free from center line segregation, once these regions are characterised by having discontinuities like inclusions, coarse carbides, heterogeneous microstructures that can accumulate ions H+, resulting in failures by Hydrogen Induced Cracking or Sulphide Stress Corrosion. This paper presents the main variables that control the intensity of center line segregation on continuous casting of slabs, striving to have homogeneous macrostructure free from defects and coarse precipitates. The casting speed and superheat are the main parameters to be controlled once they define the solidification macrostructure, being the equiaxed structure preferable to the columnar structure for the reduction of central segregation. Center line segregation intensity depends on chemical composition, being carbon, sulphur, phosphorous and manganese the main elements subject to segregation that must be reduced as much as possible. The paper presents the main caster variables to be controlled to minimize the center line segregation. Anything that affects the movement of solute-enriched liquid between the dendrites during solidification must be considered carefully. It is essential to keep the roll gap and roll alignment constant and to prevent from bulging. Higher cooling rate brings to high thickness of solidified shell, resulting on less bulging. Soft reduction is very effective but just reaches 100% of its performance when the Solidification End Point (SEP) is located at the last roll of a its segment. The sprays efficiency must be daily inspected, preventing from clogging. The water quality and its temperature control are important parameters to minimize center line segregation. The paper presents two cases pointing the importance of water and soft reduction control for minimizing center line segregation

Abstract:

Sulfur is considered a deleterious impurity to steel because it reduces the hot ductility. The maximum sulfur content specifications show increasingly smaller values, while the supply of raw materials with low sulfur content is increasingly scarce. The application of scientific fundamentals is an importatn factor for the development of the productive process and obtaining better operational results and, consequently, increase industry competitivity. In this work, the steel desulfurization process in a LADLE FURNACE will be studied from the perspective of thermodynamic and kinetic aspects with the aid of computational thermodynamics software FactSage®. Based on experimental industrial data of two types of aluminum-killed steels, one with silicon in the chemical composition and the other without silicon in the chemical composition, several parameters with influence on the evolution of desulfurization during the process in ladle furnace will be evaluated. It was possible to simulate the industrial process using the relationship between mixing power and effective mass transfer coefficient and it was necessary to apply an oxygen input rate to represent que actual reoxidation. The simulation results demonstrated the importance of the FeO and MnO contents of the slag and the slag sulfide capacity for the efficiency of the desulfurization process

Abstract:

The development the new of materials has led to the search for sustainable and better performing alternative raw materials. Natural fibers are currently targeted in order to foster and improve the materials market. These raw materials are lightweight, have good mechanical performance, and are biodegradable. On the other hand, the objective is to investigate the thermal characteristics of Mucajá fiber. The fibers were analyzed by Fourier transform infrared spectroscopy (FTIR), Thermogravimetry (TGA) and Differential Scanning Calorimetry (DSC). The FTIR results pointed to the existence of characteristic functional groups of the elements cellulose, lignin and hemicellulose. The thermogravimetry analysis at 262 ºC showed greater thermal stability and total degradation at 700 ºC. The DSC revealed that mucajá fibers have an endothermic peak close to 77.15 ºC, ∆H = 147 j/g and an exothermic peak of 54 j/g. Mucajá fibers can have potential application in several areas, especially in the field of making composite materials.

Abstract:

The ENERGIRON direct reduction technology, jointly developed by Tenova and Danieli, stands out for being capable to use a unique and well consolidated process in a wide range of operating scenarios. ENERGIRON's has the ability to process various iron oxides and utilize a range of reducing gases, including hydrogen, natural gas and COG without compromising on quality or energy efficiency. Moreover, its inherent carbon capture capability makes it suitable for green steel initiatives, facilitating phased transitions towards hydrogen-based operation while minimizing operational costs. This abstract explores ENERGIRON's unique features and its adaptability and flexibility for greener steel production.

Abstract:

The main objective of the work is to portray the emergency intervention carried out on the Hot Blast Main of Blast Furnace 01 of Gerdau Ouro Branco that took place in December 2023 at the junction of Regenerator 01, better known as Joint “T”. Due to the failure that occurred in the Hot Blast Main of Blast Furnace 01, we can describe actions to remove the symptoms, monitoring and operational continuity actions aimed at the safety of the process and people, contingency actions for possible changes in the scenario, future monitoring and coverage in other equipment on the Site. The Hot Blast Main is the equipment within the structure of the Blast Furnaces, responsible for transporting the air heated in the Regenerators and mostly enriched with oxygen to the Wind Ring, which is responsible for distributing the hot air at the base of the Blast Furnace, directed through the tuyeres so that the process of reduction and formation of pig iron can be carried out. On 12/19/23, the operation/preservation team of Gerdau Ouro Branco's Blast Furnace 01 was observed in its thermographic inspection routine, which is carried out once per shift, an anomaly located at the HS01 junction for the hot air, a region better known as the “T” joint of the Regenerators. This anomaly popularly known as “hot spot” occurred in the upper part of the junction (“T” joint) of Regenerator 01, HS01, due to the detachment of part of its refractory. The team's immediate action was to communicate with all Site leadership and reduce the flow of air blown from the regenerators with the aim of installing forced refrigeration in the hot spot to reduce the temperature of the site and preserve the affected area. Subsequently, the equipment was scheduled to stop so that the intervention could be carried out effectively and the condition of the Hot Blast Main could be restored.

Abstract:

The screening of agglomerates, including iron ore pellets and sinter feed, is a crucial step in both iron ore pelletizing plants and sinter production plants. It ensures the appropriate final granulometry for steel mills and impacts energy consumption in blast furnaces and direct reduction modules. Properly done, this process enhances bed permeability, increases plant productivity and reduces thermal consumption. Despite its importance, final screening is often overlooked by operation teams due to its few control variables, while at the same time requires frequent interventions by maintenance teams to address the mechanical issues, like parts replacement -exciter, springs and screening media - associated with vibrating screen technology. The paper introduces Metal7's innovative roller screen technology adaptation, highlighting its potential for the aggregate screening process. It addresses the limitations of traditional vibrating screens by offering enhanced efficiency and reliability in screening hard particles and aggregates across various industries. The adaptation aims to deal with critical challenges such as dust generation, excessive noise, material breakage, machine breakdowns, and maintenance-related shutdowns, ensuring higher screening efficiency and operational continuity.

Abstract:

Iron ore agglomerates have gained importance in recent years, due to the depletion of the mineral deposits and the consequent need for comminution and concentration of the minerals of interest. When exposed to natural weather, these agglomerates suffer a loss of physical quality. This article investigates the application of coatings based on waterproofing agents and dust suppressants on iron ore agglomerates, aiming to protect them from aging caused by the weather and reduce particle emissions during handling and transport. For this, 57 different products were tested, grouped according to their mechanisms of action. The tests included compression, tumbling and abrasion compression strength tests. The results indicate that certain products, especially those with hydrophobic properties, improved the resistance of the agglomerates to water and mechanical wear, reducing dust emission, maintaining physical quality for longer and reducing the aging effect observed in this type of material.

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Brazil is the largest producer of charcoal in the world and 86.08% of its production is used in the metallurgical industry. The input production process contains the kiln cooling stage, which is characterized by excessive time expenditure. In small capacity kilns, this step is carried out by natural cooling of the kiln, lasting 3 to 4 days. However, reducing the time of the cooling step requires understanding the heat loss process of the kiln. The objective of this work was to evaluate a simplified computational model of the natural cooling of a circular kiln. Heat transfer by conduction was considered in the kiln walls, in the charcoal mass and in the soil region. Heat loss from the kiln to the environment was represented by heat exchange by radiation and convection. Inside the kiln, radiative exchanges between the walls and the charcoal bed were considered. In this model, convective heat transfer inside the kiln was neglected to reduce computational resources. As a result, the final time of the cooling stage exhibited a deviation of 2.86 °C and 16.251 °C at, respectively, 0.6 m and 1.7 m above the floor. Therefore, the model can be used to predict the opening moment of the kiln. The model also presented a low computational cost when compared to natural convection models and was able to satisfactorily predict the temperature over time in the lower region of the kiln.

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Surface coating applications are used as a technique to protect and increase the lifetime and/or increase the working temperature of titanium alloys. Thermal barrier coating (TBC) applications are mainly applied on the blades of gas turbine engines. The TBC consists of a substrate, a metallic layer, BC, a thermally grown layer, TGO, and a ceramic layer, TC. The objective of this work was to study the creep behavior of Ti-6Al-4V alloy without and with BC (NiCoCrAlY) and TBC (NiCoCrAlY + ZrO2-YO1,5) coatings applied by plasma spraying. The creep tests occurred at constant load at stress of 125 MPa and at temperatures of 500, 600 and 700 ºC. The creep parameters were determined, and the characterization of the material was done by optical microscopy. The alloy with BC coating and with TBC showed an average increase in creep resistance in relation to the uncoated alloy of 77% and 131%, respectively, with a reduction in the secondary creep rate and an increase in the creep lifetime. Microstructural analyses indicated that delamination process of layers increases with the increase of the operating temperature.

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Estimating quantities in machining processes is a complicated and valuable task, since there are many parameters involved during the processes. A low-code programming tool was developed in PowerApps called Manufacturing Time Tool (MTT) to estimate manufacturing time in machining processes such as conventional turning, vertical turning, CNC turning, milling, boring and sawing. The tool uses theoretical and empirical parameters, with the empirical parameters collected in the field and the theoretical ones obtained from specific literature in the area. After 5 months of using the application, 337 samples of estimated manufacturing times were collected and compared with actual manufacturing times. The analysis was carried out using Excel, where the application's hit ratio was calculated and transformed into a percentage for each process. The results showed an average hit ratio of 96% for the sawing process, 90% for the turning process, 90% for the milling process and 91% for the boring process, demonstrating the effectiveness of the tool. The study highlights the importance of production planning, programming (PPC) and control in machining, emphasizing the importance of PPC tools in meeting customer demands and increasing the efficiency of manufacturing processes.

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Selection of primary crushing is normally a challenge in design of comminution circuits, given the impossibility of conducting tests at full scale and the lack of representativeness of small-scale tests. To address this, the Discrete Element Model (DEM) with a particle breakage model was used. The work started with detailed characterization of Super Compact Itabirite samples with the aim of characterizing the Tavares Breakage Model parameters, besides contact parameters. The performance of four primary crushers was then analyzed through simulations: jaw (Metso-Outotec), eccentric roll (FLSmidth), gyratory (Metso-Outotec) and sizer (MMD). Results show that important differences are observed between estimates by the manufacturers and simulations, which are explained by particle shape effects, besides issues related to the ore behavior. Owing to the coarse top size and high throughput demanded, the gyratory crusher appears as the most attractive alternative, even though care must be taken to guarantee that chamber level is maintained properly controlled.

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This study evaluated and presented in detail the technical and economic feasibility study for the implementation of an organic waste biodigestion system generated at ArcelorMittal's Tubarão unit, located in Serra - ES. The adopted methodology encompassed several stages such as laboratory analysis of each generated byproduct, simulations of single and co-digestions, estimation of expected biogas production, definition of the substrate pre-treatment system, sizing of the biodigestion system, evaluation of energy application, and discussion of risk scenarios for the proposed investment. The findings showed positive technical and economic feasibility for project advancement. With biometane production sufficient to replace 184 thousand liters of gasoline per year, the use of internally generated waste and byproducts at ArcelorMittal Tubarão as the primary source of raw material for biogas production makes this project an important ally in pursuing even more sustainable and efficient byproduct management, valuing circular economy throughout the production chain. Positively contributing to decarbonization and enhancing circular economy, ArcelorMittal aims with this project to valorize its waste and byproducts without negatively impacting the environment, reducing final disposal in landfills and favoring the use of renewable fuels in its internal vehicle fleet. This study also contributes to the development of the biogas and biomethane sector and to the decarbonization plan of the state of Espirito Santo, promoting circular economy and mitigation of environmental impacts.

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Wear will always be an occurrence in various industry segments and its mechanisms are directly related to high costs. Therefore, what is needed is the selection of a lining that has the best cost/benefit, i.e., it is essential to find the minimum cost for annual maintenance. The objective of the article is to show that although there are several options available, each should be carefully evaluated using a checklist of different parameters to find the most appropriate solution for specific needs. It is concluded there is no one “ready-made” solution that will solve the wear problem. There are several variables to be analyzed in addition to criteria such as solution availability, installation time, difficulty, and the cost.

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Low-code technology has gained prominence in the industry for its ease of use and versatility in developing digital solutions. This project aimed to create a simple and intuitive application for registering and tracking continuous improvement projects at Vale’s pelletizing plants. The application was developed using Power Apps and can be accessed easily via computer or tablet. It consolidates information from all areas into a single location, providing a database, cloud file storage, schedule creation and tracking, and one-page reports. The implemented solution simplified the project portfolio management, significantly reducing the time spent on this task and demonstrating the potential of low-code tools in digital transformation.

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CYBER THREATS ARE GROWING MORE AND MORE. WITH THE ADVENT OF DIGITAL TRANSFORMATION, INDUSTRIAL ENVIRONMENTS HAVE MOVED FROM AN ISOLATED SCENARIO TO AN INCREASINGLY CONNECTED WITH NEW TECHNOLOGIES, WHICH EXPOSES SUCH ENVIRONMENTS TO MAJOR THREATS. CONSIDERING THE CRITICALITY OF THESE ENVIRONMENTS, THE IMPACTS CAN RANGE FROM OPERATIONAL COSTS TO CATASTROPHES IN HEALTH AND SAFETY (E.G. EXPLOSION OF A POWER PLANT). THEREFORE, IT BECOMES NECESSARY TO ADOPT INNOVATIVE SOLUTIONS CAPABLE OF COMBATING INCREASINGLY ADVANCED THREATS, ESPECIALLY CONSIDERING THE PARTICULARITIES OF AN INDUSTRIAL ENVIRONMENT (HIGHLY LEGACY SYSTEMS, DESIGNED WITHOUT SECURITY CRITERIA, WITH HIGHLY PROPRIETARY PROTOCOLS). THE MAIN OBJECTIVE OF THIS SOLUTION IS TO CONTINUOUSLY MONITOR THE AUTOMATION ENVIRONMENT TO DETECT CYBERSECURITY THREATS AS WELL AS ANOMALOUS BEHAVIOR AND RESPOND TO THESE THREATS THROUGH NOVEL FUNCTIONALITIES. FURTHERMORE, THE SOLUTION ALLOWS ASSET MANAGEMENT BY INVENTORYING ALL DEVICES CONNECTED TO THE NETWORK (INCLUDING PLC ETC). IN ADDITION, THE SOLUTION PROVIDES VULNERABILITY MANAGEMENT REPORTING THE WEAKNESSES OF EACH ASSET INVENTORIED. TO CONCLUDE, A SECURITY OPERATION CENTER IS ESTABLISHED BETWEEN THE CORPORATE AND INDUSTRIAL ENVIRONMENTS, CREATING AN INTEGRATED CYBERSECURITY ECOSYSTEM.

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This paper aimed to present the case study conducted at Waelzholz Brasmetal, which explored the implementation of the Energy Management System to improve the organization's energy efficiency and sustainability. The methodology followed four main stages adapted from ISO 50001: Context and Planning, Support and Operation, Performance Evaluation, and Improvement. The results demonstrated the efficient energy use management, implementation of improvement actions, compliance with legal requirements and reduction of operational costs. It was observed that applying ISO 50001 requirements at Waelzholz Brasmetal provided significant improvements in energy performance, in addition to being a tool for competitiveness and environmental preservation

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The increasing need to reduce carbon emissions and the search for more environmentally friendly practices have driven the research and development of green hydrogen as a viable alternative to replacing fossil fuels in steelmaking processes. This article explores the emerging applications of green hydrogen in the steel industry, outlining the potential impacts of this sustainable energy source. Furthermore, it addresses green hydrogen production processes, the technological challenges associated with its implementation in the steel industry and compares its efficiency with conventional energy sources. In this way, the work contributes to a deeper understanding of the implications of green hydrogen in the steel industry, highlighting its role in the transition to cleaner and more sustainable industrial practices. In the other hand, it will show some initiatives of ArcelorMittal on green hydrogen.The findings offer valuable insights for researchers and industry professionals seeking to promote sustainability in steel production

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In this study, samples of a cold-rolled 3rd generation AHSS of the 1000 MPa strength class were evaluated on slow strain rate tests (SSRT) under different conditions of hydrogen charging. Using the thermal desorption analysis (TDA), two diffusible hydrogen levels were obtained in the steel and thus their effect on the degradation of mechanical properties in tension was compared to the uncharged condition. For the lowest hydrogen content evaluated, of the order of 0.61 ppm, there was no considerable loss of mechanical properties in relation to the uncharged condition. However, for the highest hydrogen concentration, close to 1.16 ppm, a significant drop in total elongation values was noticed, with a calculated embrittlement index of 38.3%. The methodology applied made it possible to distinguish the degradation of mechanical properties depending on the hydrogen concentration of the material, constituting an important tool for the development and application engineering of AHSS for the automotive sector.

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Technological competitiveness and OpEx reduction combined with the shortest possible downtime are the driving forces for a revamping project. In this paper a real case of a turn-key project performed by Danieli Centro Combustion on a HDGL annealing furnace is presented. Cooling and soaking sections of the furnace have been modified from horizontal to vertical configuration and most of the erection has been safely performed during normal production with the aim of downtown minimization. The outcomes of the project are productivity increase, natural gas consumption reduction and product mix extension, permitting the customer to produce AHSS grades thanks to the increased soaking time in the radiant tube section and the rapid cooling section.

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Annealing heat treatment is usual after cold drawn process of SAE 4130 steel, considering the requirement to obtain ferrite and pearlite microstructure and higher ductility. This work evaluated the effects of full annealing and intercritical annealing heat treatments after the cold drawn process. Mechanical properties and the final microstructure obtained in both routes were evaluated. It was observed that the full annealing route presented ferrite and lamellar pearlite, whereas the intercritical annealing route presented ferrite and degenerated pearlite. The difference in microstructure affected the mechanical properties, as observed in yield strength, hardness and elongation. Although the yield strength did not present significant differences for both routes, the full annealing route showed higher tensile strength and hardness than the one found in intercritical annealing route. Considering the increase in ductility as the main objective, the intercritical annealing proved to be more efficient.

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Oxygen converters have programs to determine lance-to-bath height (DBL) from reference measurements of the bottom and bath levels. These references are length measurements that represent a volume. However, they are punctual and generally taken as a reference to the center of the converter. This article investigates the effect of the uneven rise of the BOF bottom on lance leakage. The results show that non-uniform bottom elevation is the cause of premature lance leakage and suggests some countermeasure actions

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This work aims to determine the influence of solidification/cooling parameters on the microsegregation of HSLA+Nb steel slabs at different positions. Microsegregation is seen as one of the most important sources for variability in metallurgical properties, especially toughness, and measures that seek to reduce the microstructural banding and preferential precipitation will result in greater microstructural homogeneity and lower properties variability. The samples were taken at positions along the width (Center and -294mm in relation to the center) and thickness of the slab (12.50, 37.50, 102.50 and 125.00mm). Electron Probe Microanalysis (EPMA) by Wavelength-Dispersive X-Ray Spectroscopy (WDS) was performed to quantitatively characterize the microsegregation of several elements (C, Mn, Si, P, S, Nb and Ti) in the dendritic and in interdendritic areas. SDAS (Secondary Dendrite Arm Spacing) measurements were carried out, which allowed to calculate the cooling rate, using published equations, in each position. This work allowed to understand in detail the behavior of the different chemical elements in different positions in a cast slab, as well as to determine the influence of the cooling rate on this behavior. This knowledge can be the basis for process optimizations aimed at reducing microsegregation in products where microstructural homogeneity is a critical product quality factor.

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For the purpose of extend the life cycle of the RH lower vessel campaign, increase operational safety and reduce CO2 emissions, ultra-low carbon (ULC) refractory bricks were developed, which have a low carbon content (≤ 1.8%wt) using a special type of graphite for application in the throat region of the RH lower vessel. Initial tests carried out in partnership with RHI Magnesita indicated significant improvements. The results show that the performance achieved with the MgO-ULC lining surpasses that of the magnesia-chromite bricks traditionally used, indicating a longer life cycle potential. In addition, it was found that it is possible to produce ultra-low carbon steels under these new conditions. At the same time, interest is growing in the development of new materials for lining RH degassing vessels. Traditionally, the RH vessel is lined with chrome-magnesium materials, a choice driven by the needs of the process, which aims to reduce the carbon contained in the liquid steel. Refractory linings that deviate from the chrome-magnesian composition are rare, highlighting the need for innovation in this sector.

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Iron ore is predominantly transported by rail in open wagons. Therefore, it is crucial to take special precautions to prevent wind erosion of the cargo during transit. Wind erosion can lead to economic losses and significantly impact air quality in areas surrounding the railway network. Consequently, railways handling this type of cargo implement specific systems to control particulate emissions during iron ore transport. In this context, the project's scope is to prepare and characterize polymeric films capable of performing this function. The films were prepared using chitosan as the polymer, due to its ease of manipulation and biodegradable nature, and a 4% acetic acid solution as the solvent. The films produced from these solutions underwent absorption and wind tunnel tests. These procedures were implemented to establish the essential parameters for producing an effective film that meets market demands and helps address the current challenges in iron ore transport.

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The source of the problem is where the best solution will come from. The principle of circularity states that all waste needs to find a sustainable solution and many other predicates. CO2 equivalent emissions will be reduced by increasing the efficiency of coke-integrated steelmaking, increasing the iron content in ores and replacing fossil carbon with renewable carbon in sintering and injection into AF. CO2 reduction can exceed 50% without new technologies. Seven examples of how to reduce emissions in the integrated plant with minimal capital and with productivity gains in the Blast Furnace and BOF, less sulfur in the pig iron, less carbonates and much less AF slag. The richer iron sinter feed (+3.2%) and the greater use of scrap in the BOF converter (13.8 to 19.8%) reduce emissions by 13%. Using charcoal in the agglomeration and injection of pulverized charcoal reduces CO2 by 37.8%. Combining iron enrichment with partial replacement of the fossil (in sintering and PCI) this CO2 reduction reaches 49.1%. All this with a reduction in the use of limestone and lime and lower sulfur content in the pig iron and lower emissions of SOx, NOx, and others.

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The Blast Furnace 1 at Ternium Brazil began its campaign in 2010. During this period, it had not faced operational instability lasting nearly 47 days. The causes of the operational instability, which obstructed the 32 tuyeres, were the loss of thermal load generated by the irregular distribution of burden. The major challenges faced were the difficult slag runoff and the loss of communication between the tap holes and the tuyeres. The solutions found involved the use of oxygen and natural gas lances through the tap holes. After the recovery of the blast furnace, the importance of the reliability of measurement instruments and reinforced sealing in critical regions of the tuyeres was recognized, in addition to the need for persistent use of natural gas and oxygen lances.

Abstract:

The sinter feed chemical composition determines an important role in its assimilation property and consequently the sinter quality. The sinter contaminants imply higher blast furnaces’ slag volume, which can reduce their productivity and the pulverized coal injection rate. One of the contaminants that has increased considerably is alumina, which impacts the physical and metallurgical sinter quality and the sintering process productivity. Therefore, the present study focused on studying the effect of different alumina sources on the iron ore assimilation properties and the impact of this compound on the sintering process and sinter quality. From the results, it was found that alumina in hydroxide form is more harmful to the sinter quality than its silicate form. Furthermore, alumina harmed the sinter pot test productivity, sinter mechanical resistance and, considerably, the reduction degradation index (RDI) of the sinters produced.

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In High Pressure Grinding Rolls (HPGR) the particles within a continuous flow of passing ore between the rolls are subjected to high pressures, resulting in their fragmentation and specific surface gains. Its application in grinding iron ore concentrates for pelletizing is associated with increased productivity and pellet quality. In this process, it is common to use roll surfaces composed of studs made of wear-resistant material, Tungsten Carbide (WC). Despite the advancements in this material, wear resistance remains the major challenge in extending the lifespan of the rolls. Analyzing the studs wear mechanism, 8 classes of WC studs were defined for a field test with different percentages of Cobalt (Co) and Nickel (Ni) binders and varying carbide grain sizes. The modified studs were evenly distributed around the roll’s perimeter, with rows of 63 units for each class, being tested over more than 26 thousand hours, approximately 4 years of operation, during which 11.3 million tons of ore were processed. Stud wear was monitored by measuring their height throughout the testing period, totaling ten measurements using a perforated ruler and caliper. The best results at the end of the test showed a wear reduction to less than 0.45 mm/1000 hours of operation or 1.04 mm/ton of processed ore. This corresponds to an increase in stand lifespan of over 25% compared to commonly used studs.

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In this study, a 2D axisymmetric multiscale model was proposed to describe the direct reduction of iron ore process in a moving bed reactor. The system comprises the downward movement of porous iron ore pellets reacting with the countercurrent gaseous flow entering from the side and lower part of the reactor. The grain kinetic model and the mass, heat, and momentum equations for the two discretized physical of pellets and reactor were solved using finite element method. The results provided a detailed evaluation of the heterogeneities within the reactor and solid pellets, demonstrating good predictive capability with data from an industrial direct reduction plant. The model can be extended to design the process for the energy transition towards low-carbon iron production by increasing the hydrogen content in the process.

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The present work addresses the evaluation of gears that make up electric vehicle differentials. The SAE 4320 and DIN20Mn5Cr steels were manufactured through the microfusion process, carburized and heat treated through martempering with tempering and austempering with sub-zero cooling with evaluation of the macrostructures, microstructures and microhardness profile starting from the carburized layer towards the core. During their evaluation, the pieces underwent standard metallographic preparation with different types of metallographic attack to evaluate their microstructures under an optical microscope and scanning electron microscope. A primary grain size analysis was carried out using specific metallographic etching. The macrostructure revealed cemented layers with lower thickness for group B. In the microstructural analysis, the formation of a normal microstructure of martensite and bainite was observed for groups A and B, SAE 4320 steels, whereas groups C and D, DIN20Mn5Cr steel, showed formation of martensite and bainite together with retained austenite indicating a possible weakening of the components in their subsequent application. The microhardness profiles indicated higher hardness for the materials that underwent martempering and tempering in relation to the austempered+sub-zero materials.

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Drum replacement in a belt conveyor is a critical maintenance task that requires structured planning to ensure safety and efficiency. This article provides a detailed analysis of the procedure, including the use of specific devices and techniques for drum replacement. It addresses the importance of safety and best maintenance practices to maintain asset integrity, highlighting the use of safety devices and engineering techniques to mitigate risks. The conclusion emphasizes the need for training and use of protective equipment.

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The use of wet-shotcrete as an installation technique has become widespread worldwide due to its simplicity and benefits such as form-free and fast installation, minimum dust and rebound, short turnaround times and good thermo-mechanical properties. In recent years, colloidal silica bonded shotcrete castables have been used in different refractory applications combining faster and safer dry-out and superior refractory lining performance when compared to cement bonded castables. The development of high-performance shotcrete castables depends on several factors, including the use of suitable shotcrete accelerator. This study investigates the influence of different shotcrete accelerators, A (reference) and B (new develoment), on the installation characteristics and properties of a colloidal silica bonded refractory castable. An Al2O3-SiC-SiO2-C based sol-bonded castable was shotcreted using accelerator A or B and the refractory panels were characterized after drying and firing at different conditions. Results showed that accelerator B provided a smoother reaction with the silica sol binder, eliminating material pulsation during shotcreting, also improving the materials´ surface finishing. Although no substantial differences were noticed in the physical properties, a significant improvement in mechanical strength (MoR, CCS and HMoR) and abrasion resistance was observed when using accelerator B. Therefore, the choice of shotcrete accelerator can significantly influence the installation quality of sol-bonded refractory castables, positively impacting the installed material´s properties and enhancing the refractory lining performance.

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The Steeltrack project was developed to automate the collection and interpretation of planning and logistics’ informations from Arcelormittal Brazil Flat Carbon. The system provides analytics and predictive indicators that assist on decision-making in differents business areas, also improving performance and anticipating possible problems.

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The indirect coke temperature measurement system used on AcelorMittal’s Coke battery is a project which objective is to obtain the coke oven wall’s temperature curves during the pushing operation. The system is based on the integration between the control systems and the Lynx Process Platform LYNX RTP (RealTime Plataform). This platform provides a layer of computer intelligence totally integrated with the current automation architecture on the industrial plants. The data read by the pyromethers connected on the PLC’s of each machine can be treated, processed and used for decision-making on several industrial necessities. The integration between the Lynx RTP and the controllers network allow the new technologies and computer models to be used on the automation process, forwarding with the digitalization and integration of the most current market technologies

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Biodiesel emerges as a valuable commodity in Brazilian agriculture, offering opportunities for energy diversification and mitigation of polluting gas emissions. However, its quality assurance faces obstacles, such as oxidation during storage and transportation, as well as the tendency to crystallize at low temperatures, challenges aggravated by the country's extensive road network and climate variability. As for nitrogen oxides (NOx) emissions, there are discussions about their impact, with divergent studies. Despite the potential, the large-scale replacement of petrodiesel faces challenges due to restrictions in the production of vegetable oils and their prioritization in human food. Thus, it is crucial to review policies and investments to boost biodiesel, including considering crops exclusively for energy. This literature review seeks to provide a comprehensive overview of the current state of biodiesel application in Brazil, highlighting the challenges faced and alternatives to these issues.

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In the mining industry, the use of conveyor belts to transport large volumes of material over long distances is common and facilitates the productive flow. However, due to operational characteristics, no-load operation of these systems can be frequent. This paper addresses the reduction of conveyor belt drive motor speeds when operating without load as an effective strategy for optimizing operations in the mining sector, ensuring improved performance and focusing on aspects such as increased efficiency and operational profitability, in addition to minimizing environmental impacts. The analysis of idleness in the presented circuit and consideration of optimized operation showed a high potential for avoided loss.

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The AISI 420A (SUS420J2) stainless steel is commonly subjected to quenching and tempering heat treatments when intended for various high-value applications. However, the proper selection of the austenitizing temperature, a step preceding the fast cooling in quenching, remains challenging. Numerous reports in the literature, as well as in industry, make it clear that slight alterations in this parameter strongly modify the mechanical properties of tempered products, even when using the same cooling rate. In this context, the present study aimed to evaluate the effect of the austenitizing temperature on the carbide dissolution and the martensitic transformation in this steel. For this purpose, resources such as computer thermodynamic simulation and dilatometry were used concomitantly with structural characterization techniques. It was concluded that with the increase in temperature in association with the continuous carbide dissolution, there was a significant austenite enrichment in C and Cr, which strongly contributed to the decrease in martensitic transformation critical temperatures. In this scenario, the increase in austenitizing temperature led to a significant hardening of the martensitic microstructure, reaching up to a 59% increase in Vickers hardness with a 275°C increase in this heat treatment parameter.

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This article describes the roll reclaiming by welding and reuse of the vertical edger rolls in a Hot Strip Mill and the advantages and economic results. The roll surfacing materials should be reasonably selected and the surfacing repair plan formulated based on the rolling operation conditions to maximize the roughness of the surfacing repair. The surface quality of the roughing vertical rolls during rolling is continuously improved and the edge quality of the strip is improved, and the consumption of the rolls is reduced.

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The scale formation in a reheating furnace depends on the O2 content at high temperature and the charging permanence time inside the furnace chamber. As the temperature and the permanence time of the steel inside the furnace are parameters that cannot be changed because coming from the process, the only way to reduce the scale formation is decreasing the O2 content in high temperature zones. For this reason, Danieli Centro Combustion studied and already supplied three H2 Ready Scale Free Furnaces, that have the features to be capable of operating in reducing atmosphere, in a completely safety condition. The sealing of the furnace avoid the exit of dangerous incombustion gases but also the entrance of false air, responsible for an increase of the specific consumption. The Scale Free Furnace technology, compare to a traditional Walking Beam furnace, halve the scale formation and reduce of approx. 5% the fuel consumption and CO2 emissions

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The performance of a steel mill relies heavily on the stability of its production equipment, with combined blowing being crucial to ensure the chemical homogeneity of the steel, thereby decreasing the total iron content in slag (metallic yield) and enhancing the dephosphorization rate. The combined blowing system comprises a set of tuyeres for injecting inert gases from the bottom. During tuyere operation, various fluid dynamic phenomena occur, leading to increased refractory wear, decreased lifespan, and disruptions in combined blowing operations. This study aimed to develop a new tuyere design to enhance the steel mixing rate and reduce wear, ultimately improving the efficiency of combined blowing.

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The Steelmaking Plant 2 of Usiminas operates with two casting machines with two strands each. A diagnosis of the secondary cooling spray air mist nozzle showed a water distribution profile performance of 50% and variability in the heat transfer coefficient of 38%. In front of this, the spray nozzle supplier developed a new bench design that increased the regularity of the distribution profile to 80% and reduced the variability in the heat transfer coefficient to less than 10%. Subsequently, a comparative test was carried out on one of the strands. The experiment strand with the new spray nozzle design showed greater thermal regularity across the slab width and a smoother and more gradual thermal transition between segments. An increase in slab quality was also found by reducing the intensity of the central segregation thickness by up to 0.50 mm, reducing the intensity of the size of horizontal cracks by 47% and reducing the formation of superficial cracks by 12.5% in peritectic medium carbon steel scarfed. The new spray nozzle design creates opportunities for the development of new spray plans and enhances the potential for slab quality improvement.

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Over the years, rebonded magnesia-chromite bricks have been extensively utilized in critical regions of RH Degassers. However, with the evolution of steelmaking processes requiring higher-grade steel productions, arises a need to enhance these materials to achieve the new demands placed on refractory during applications. The objective of this study was to identify the primary factors contributing to the current situation and create effective solutions to address these challenges. This paper provides an overview of the steps taken to identify the main issues, along with the methodologies employed to thoroughly understand all variables. This study delved into the challenging performance scenario encountered in the RH Degasser at Gerdau Ouro Branco, utilizing magnesia-chromite bricks from RHI Magnesita. Prior to implementing any alterations to the refractory, a thorough and extensive understanding of the case was pursued, aiming to determine the primary causes and propose technical solutions aligned with GOB's objectives. A novel technology for measuring wear rate was developed, providing insights through its innovative measurement concept. In-depth thermomechanical simulation studies were conducted, leading to a comprehensive understanding of the primary mechanisms experienced by the refractory. Following adjustments to the refractory concept based on these findings, a successful turnaround in the RH Degasser was succeeded, with throats achieving a potential of 350 heats.

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The increasing industrial demand for sustainable products has driven research into new components that combine efficiency and eco-friendliness. In this context, polymeric composites, particularly those reinforced with natural fibers, have gained prominence. Epoxy, widely used due to its exceptional properties such as easy handling, high strength, and effective adhesion to reinforcements, is one of the most employed polymers in these materials. Studies have shown significant improvements in the physicochemical properties of the resin when reinforced with natural fibers such as Agave, Bamboo, Linen, Jute, Kenaf, and Sisal. Sugarcane bagasse, an abundant lignocellulosic residue composed mainly of cellulose, hemicellulose, and lignin, emerges as a promising reinforcement alternative for epoxy resins. This work aims to investigate the characteristics of sugarcane bagasse through techniques such as X-ray diffraction and infrared spectroscopy, with the objective of assessing its feasibility as a reinforcement in high-performance coatings based on epoxy resin.

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During steel production a large volume of solid waste is generated. Some are commonly reused, while others, e.g. containing zinc, have restricted use in the traditional steelmaking route. Zinc, the fourth most consumed metal globally, has primary reserves that are limited compared to global demand. This study presented a new pyrometallurgical route to recover zinc from steelmaking residues using the Tecnored Recycler pilot furnace. In the first step, self-reducing briquettes doped with high-purity ZnO were used to evaluate the furnace's behavior. In the second stage, briquettes containing by-products were tested. The results indicated that the Tecnored furnace can efficiently operate with charges containing up to 10% ZnO, maintaining the quality of pig iron and the thermal performance of the furnace. Zinc recovery was significant, with concentrations exceeding 50%, highlighting the technology's potential to improve this efficiency. The specific geometry of the Tecnored Recycler furnace and its gas cleaning system were essential for the process's effectiveness. This development proposes a sustainable, low CO2 emission solution for recycling steelmaking residues, contributing to the circular economy. Additionally, it adds value to by-products and enhances the sustainability of pig iron production.

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Usiminas’ Blast Furnace#3 ended its 4th Campaign on April 24, 2023, after 23.5 years of operation. The 4th Campaign was designed for 15 years, with 41 million tons of hot metal as estimated production. Accumulated production reached 57.8 million tons, exceeding the value forecast for the campaign by 41%. The results of accumulated productivity and campaign life spotlights the Blast Furnace 3 in the global steel industry. This paper shows the main operational results evolution, process improvements introduced and preservation of the blast furnace lifespan.

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The Brazilian steel industry has a challenging decarbonization agenda with important consequences for its domestic and global competitiveness. In this context, the sintering process represents an important portion of the primary iron manufacturing stage emissions. In this work, a model of the multiphase multicomponent sintering process coupled with chemical kinetics is used to analyze the possibility of partial substitution (40% of the fossil fuel) by charcoal. Results of 5 case analyses, compared to the reference case, indicate a predicted reduction of fossil CO2 equivalent emissions of approx. 80 kg CO2 equivalent per tonne of sinter produced.

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In the iron ore pelletizing process, anthracite is used as a solid fuel in the formation of green pellets, and its fundamental role in the burning stage is to reduce the thermal gradient between the top and bottom of the pellet layer. This allows for better energy efficiency in the process, resulting in reduced costs and improved physical and metallurgical properties. However, because it is of fossil origin, anthracite is one of the inputs that contributes most to the emission of Greenhouse Gases (GHG) in Vale's operations. The paper presents the results obtained both in a pilot plant and on an industrial scale during tests to replace anthracite with biocarbon (from renewable sources).

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Steel mills, responsible for 10% of CO2 emissions worldwide, seek to reduce their carbon emissions, and a promising solution is the use of biomass as an energy source. Eucalyptus bark emerges as a viable option in this context. Besides offering a sustainable alternative for energy production in the steel industry, its use also contributes to reducing environmental liabilities, as these residues are frequently disposed of in landfills. Thus, the use of carbonized eucalyptus bark as a partial substitute for the coal used in the coking process not only promotes carbon emission mitigation but also helps manage vegetable residues more efficiently. The present study investigates the technical feasibility of eucalyptus bark carbonization using a circular furnace of the "hillside hot tail" or "barranco" type. The results obtained demonstrated a satisfactory increase in volatile matter, from 76.2% to 25.8%, and in ash content, from 5.6% to 9.8%, resulting in a carbon-rich residue suitable for use in the steel industry.

Abstract:

SAE 8620 steel is widely used in the industry due to its combination of high strength, toughness, and good cold formability. Spheroidization heat treatment is a crucial process for enhancing these properties, preparing the steel for subsequent cold forming operations. This study aims to investigate the effects of spheroidization heat treatment parameters on the microstructure and degree of spheroidization of SAE 8620 steel. By using microstructural characterization techniques on samples treated in a muffle furnace, the impacts of temperature, holding time, and cooling rate after heat treatment were investigated. The results indicate that optimized spheroidization parameters can significantly improve the degree of spheroidization of the samples, reducing process times.

Abstract:

At ArcelorMittal Tubarão FCLatam (Flat Carbon Latin America) asset management was implemented through the 5 Star Asset Management Program, the implementation process of which in the Continuous Casting Operation will be explained in this article. This program has evolved over the years, promoting new themes that can contribute to asset management. The program seeks the continuous evolution of reliability, quality and sustainability in Continuous Casting machines at ArcelorMittal Tubarão. The implementation of the 5 Star Operations Program is aligned with the company's strategic planning in the flat steel segment. Managing all these operational activities in a large industry is a task of extreme importance for the business results, but quite challenging, given the high number of employees involved and the level of technical responsibility for the activities in question. To ensure adequate execution in terms of method, frequency, responsibilities, adequate recording, assertiveness in tasks, it is essential to guarantee an efficient management system with this focus. In this context, the 5 Star Program was applied to the operation management of Continuous Casting at ArcelorMittal Tubarão to improve the management of the operation process as a whole. The methodology applied is based on maturity levels (fundamental, intermediate and advanced), where each level has supporting pillars. Some examples of pillars are: training, standardization, operation plans (PGO), H&S and environment, alarm and failure management, roles and responsibilities, variable cost, autonomous maintenance, asset use, operational efficiency, reaching advanced pillars such as risk management, supply chain, new technologies, interface management (Stakeholders) and human reliability

Abstract:

Solid fuels are the main source of heat supplied to the iron ores sintering process. Understanding the behavior of the fuels used in the process can represent a difference both in terms of optimizing this raw material in the mixture to be sintered and in operational performance itself. From an understanding of the relevance of the topic, the work proposed to evaluate the reactivity of 4 qualities of solid fuels used in the sintering process at ArcelorMittal Tubarão and establish a relationship between this property and some variables. Thermogravimetry and differential scanning calorimetry techniques were used to identify that the anthracite samples are more reactive than the coke samples. The most reactive anthracite sample showed a difference of around 16.3% compared to the least reactive coke sample. When compared between samples of the same nature, the anthracite samples showed no significant difference in reactivity between them, while the coke sample produced via the conventional coking process was around 6.5% more reactive than the coke sample produced via the heat recovery process. Among the variables evaluated, the fixed carbon content and the amount of ash present were the ones that most affected the reactivity of the samples.

Abstract:

The vacum filtration process involves separating solids and liquids using a filter medium. The objective of the work is to increase process productivity by evaluating the use of subscreens. The methodology includes monitoring and field tests with the filter in operation, allowing a detailed analysis of process behavior. The results from these tests validated the benefits of using subscreens in the filtration process. In addition to increased produvtivity, subscreens also contributed to reducing defects in the filter fabrics.

Abstract:

The sintering process is the result of a good quality selection of the raw materials consumed with efficient homogenization of this mixture. To obtain good performance of this mixture in the process, the preparation of the requires a good agglomeration process, which seeks the growth of quasi-particles through the addition of burnt lime and water in equipment designed for this purpose. In this way, adequate permeability is obtained for the sintering process, making sinter production viable. Given the scenario of quality degradation and thinning of ores and worsening of the nucleating/adherent ratio experienced by ArcelorMittal Tubarão Sintering, the process has required the need for better agglomeration conditions to ensure good performance of the production process. In order to overcome the current difficulties, an industrial test was carried out to replace the burn lime currently consumed with micro-pulverized burnt lime. The test result showed a good potential for recovery of 4% in productivity with a 9% reduction in quicklime consumption, showing that it is advantageous for the industry to replace conventional burnlime with micropulverized burnlime.

Abstract:

The real-time monitoring of the size distribution of the raw pellet entering the kiln is directly related to the efficiency of the roller table classification. Given the difficulties in dealing with the granular flow of the pellets, there is a need for the development of a model that allows for predictions of flow characteristics on the furnace feed. In order to achieve this, a phenomenological model of the roller screening raw pellets was developed and validated using the discrete element method (DEM). The model allows, with lower computational cost, online monitoring of how variations occurring in pelletizing can influence the furnance permeability through the entry of fines into the bed of raw pellets

Abstract:

The sintering process demands continuous control of a large number of process parameters, where the internal temperature of the Ignition Furnace is the main parameter to ensure the initial burning of the mixture to be sintered. This article aims to explore the challenges of implementing an automatic control system, presenting operational aspects and PID control adjustments

Abstract:

In mining, the formation of scale is a constant and inherent challenge in the most varied mineral processing operations, directly affecting the unit operation related to the problem, be it reducing the efficiency of pumps and pumping systems, filtration processes, pipes in general, evaporators and heat exchangers among others. Specifically in this Case Study (Iron Ore Processing Plant located in Brazil) the ScaleTrol PDC 9325 program was used as a way to control and inhibit the constant formation of scale, mainly formed by calcium carbonate and iron oxide in the washing system of gases (precipitator tank), which significantly reduced the physical availability of the system, overloading the circuit and causing interruptions and unscheduled stops for unblocking, cleaning and/or changing pipes

Abstract:

The tribocorrosive behavior of two tool steels, AISI H13 and D2 steels, was investigated using Miller equipment using a methodology adapted from the ASTM G75 standard. Two types of iron ore slurries were used, and another one of a normal Brazilian sand (IPT) with a grain size of 0.30-0.15 mm. D2 steel (61 HRC), characterized by the presence of chromium carbides in a martensitic matrix, showed superior tribological performance when compared to H13 steel, a martensitic steel with a hardness of 52 HRC. Using the sand slurry as a reference D2 steel showed less wear, being 1.5 times less with the A1 ore slurry and 5 times less with the A2 ore slurry. The classification was observed for abrasiveness of the slurries: Sand>A1>A2. The images of the wear surfaces showed less corrosion on D2 steel compared to H13. In addition, both materials showed a greater trend to corrosion in wear tests with iron ore slurries. In the aim of increasing the useful life of an iron ore agglomeration equipment, AISI D2 steel showed high wear resistance, with the prospect of scalability for field tests.

Abstract:

The extraction of mineral resources begins with the project, followed by site construction, operation, closure, and final rehabilitation. The consumption of fuel and electricity associated with open-pit mining processes is one of the main sources of Greenhouse Gas (GHG) emissions. There are few studies dedicated to sustainable mining projects, indicating opportunities in this area. MAFMINE is software for mining projects, and the objective of this article is to describe the construction of the emissions module for MAFMINE ESG. This will allow for the determination of the economic and environmental sustainability level of open-pit mining projects. The development of a database for estimating emissions in mining projects is presented, using the information from MAFMINE reports as a starting point. Currently, the equipment quantified and dimensioned are trucks and excavators. The nominal capacity of these will correlate with the CO2 equivalent emission factor to generate the parametric models. Thus, a model with a simplified approach is proposed, aiming to offer a simple and quick response for the designer's decision-making.

Abstract:

All along its history, mining has significantly contributed to the development of societies. Its capacity to generate jobs and income makes nearby communities increasingly economically as well as socially developed. Nevertheless, just like any other industrial endeavour, mining activity has its negative aspects. Comparing the main aspects of the relations between mining industry and the communities that are part of its operational process, the results present the outcome of social and environmental ills that must be further mitigated by those involved in mining activity. The impacts of the building of an industrial zone in the outskirts of cities like Mariana and Ouro Preto turn them into a stage of social-cultural and economic phenomenoms capable of directly influencing the day-to-day life of the native population, as well as that of migrants who leave their places of origin to search for better conditions of life and labor.

Abstract:

Mining is an ancient activity of extracting minerals from the underground, used to produce essential items, but it can also cause negative impacts. It generates jobs and contributes to the economy, yet it requires environmental and social licenses to minimize damages and engage communities. Sustainability is crucial, balancing environmental, social, and economic aspects. Projects like "Lithium Valley Brazil" exemplify the pursuit of economic benefits with environmental responsibility.

Abstract:

A common layout found in a primary crushing stage is a jaw crusher combined with vibrating grizzly feeder, usually without direct measurement of what is being fed into the crusher, in terms of feed rate or particle size distribution. Considering this, problems with jaw crushers overloads and obstructions are frequently encountered, causing operational stops and productivity reduction. This paper describes the development of a control strategy, applied in a Vale’s iron ore plant, capable of regulating the process in face of jaw crusher capacity violations caused by an overlimit feed rate or an overdimensioned material. The controller process variable used was an already existent crusher motor current, which is a reliable measurement, with high availability and requires small maintenance efforts unlike other instrumentation options. The results indicate an increase in operating hours between stops of 2.81 hours and a reduction of 9.8 percentage points in the ratio of unavailable hours per operating hours. Furthermore, there was a 9.0% increase in the average mass flow rate during the block restriction periods.

Abstract:

Filtration, a unit operation in mineral treatment, involves passing ore pulp through a filtering element to retain the solid and allow the liquid to pass through. This process can face issues such as filtration efficiency, product losses, water consumption, and high operational costs. To produce zinc concentrates with a maximum moisture content of 11%, the PDCA methodology was applied, focusing on the "Plan" phase using filter presses. The investigation centered on the statistical feasibility of the company's moisture target, using gap and quartile methods, and quality tools for process stratification and analysis. Issues such as manual filter discharge, lack of plate structuring, and the absence of dedicated operators compromise process efficiency, affecting the moisture content of the products. The "Plan" phase of the PDCA Cycle resulted in a proposed action plan that can be strategically applied to filter operations, aiming to ensure that Zn concentrates meet the company's 11% moisture target.

Abstract:

Phosphorus is a very important element for society. It is vitally important for the survival of any living being, especially in the production of energy in cells and in the formation of DNA. Its most stable form is in saline form, phosphate. The main way to find phosphates is in minerals, and apatite is the main one. In the phosphate rock where apatite is found, several other gangue minerals are also found, such as calcite, dolomite and silicate minerals, so the concentration stage is necessary to raise the P2O5 content in the concentrate to make it viable to use this mineral asset in agriculture. Flotation is therefore an important process for concentrating phosphate. This work studied the efficiency of a B100 biodiesel, supplied by Óleoplan Nordeste, used as a collector, in order to evaluate the flotability of apatite, dolomite and calcite, looking for a selectivity range

Abstract:

The moisture content in the ore is a result of this beneficiation process, in addition to inherent moisture within the mineral composition. The moisture content of iron ore is a crucial parameter that requires effective control to ensure safe handling and transportation operations. Surface plasma treatment of iron ore has been investigated as a method to enhance the hydrophobicity of ore particles, thereby reducing residual moisture and water reabsorption by the particles. The samples underwent treatment using cold plasma of argon and hexamethyldisiloxane (HMDSO) plasma, leading to the formation of a thin, silicon-rich surface layer. The plasma treatment resulted in a reduction in moisture content and water absorption. The reabsorption of water decreased to approximately 35% of the pre-treatment values. Contact angle measurements demonstrated that all HMDSO-treated samples exhibited hydrophobic behavior, with contact angles ranging from 110° to 120°, while the untreated samples exhibited angles close to 0°

Abstract:

Lithium, one of the so-called “critical minerals”, defined in the National Mining Plan 2030, has gained prominence in academic research and the mineral industry in recente Years. Its most importante deposits are found in brines and pegmatites, the latter a hard rock with important occurrences in Brazil. In this work, pegmatites from Eastern Minas Gerais, classified as albite-spodumene type, the main variety of pegmatite for lithium ore, had their main minerals and mineral associations characterized by several analytical techniques: steromicroscopy, X ray diffraction, X ray fluorescence, X ray micro-fluorescence, optical emission and laser ablation spectrometries, in order to identify the main lithiferous phases, and the amount of lithium contained in different minerals

Abstract:

In the present work, the effect of the recycling process on the properties of polycarbonate was evaluated. For this, specimens were produced by injection of virgin polycarbonate and injected polycarbonate, which were used in transmittance analysis, Scanning Electron Microscopy (SEM) and mechanical tests (reaction and hardness). These analyses revealed significant changes in the properties of this material after the recycling process. The transformation in mechanical properties is crucial to understand the changes that occur during the recycling process and how they impact the performance of polycarbonate in different applications In the conclusion of the study, it was observed that recycled polycarbonate exhibits behavior akin to that of a thermoset polymer, while virgin polycarbonate demonstrates characteristics closer to those of a thermoplastic. This distinction appears to significantly depend on the procedures employed during the recycling processes. These discrepancies underscore the importance of considering not only the chemical composition but also the recycling methods in assessing the properties and behaviors of polymeric materials.

Abstract:

Since 2015, the Usiminas Mobiliza pelo Caminhos do Vale program has used steel aggregate for the primary coating of rural roads in the Minas Gerais region, promoting improvements in infrastructure and quality of life for residents. A study was conducted by the contractor, HidroGeo Engenharia e Gestão de Projetos Ltda, to evaluate the possible risks to human health and ecology associated with the use of this material applied to roads and its storage in yards. The analysis included a historical review of fieldwork and program information, with the aim of determining risks in specific exposure scenarios, considering concentrations of chemicals of environmental concern (SQI). The process involved identifying the SQI, exposure routes and potential receptors, seeking a detailed understanding of the environmental and health impacts related to the use of the steel aggregate. Based on the information collected, the study concluded that there is no potential risk of contamination of appropriate receptors in the evaluated scenarios.

Abstract:

Scientific initiation has as one of its main objectives, to add to the student's development through practice, allowing them to have, in many cases, the first more in-depth and technical contact in their course. During this process, the student develops some skills, such as writing and speaking. Furthermore, they stimulate critical thinking, awakening curiosity, innovation and learning in the individual, by dealing with issues in their area of study, making them a flexible and adaptable professional. Therefore, this work aims to disseminate the importance of scientific initiations, evaluating their influence on mining engineering students at the Federal University of Ouro Preto (UFOP) over the years 2013 to 2023. The data was obtained by collecting perspective of students and alumni and the lattes of the faculty of the Department of Mining Engineering (DEMIN) at UFOP. The results obtained indicate that the students who participated showed, at the end of their ICs, development in their technical and personal skills. In addition to pointing out that ICs were the initial stimulus for new opportunities.

Abstract:

The present work aimed to synthesize "4A" zeolites from kaolin waste and apply the synthesized product in ion exchange. For the synthesis of 4A zeolite, the waste was calcined at 700°C for two hours to transform it into metakaolin. After calcination, the metakaolin and NaOH solution were introduced into a synthesis system, regulated to a temperature of 100°C and a rotation speed of 700 RPM for 30 minutes. For ion exchange, the same synthesis system was used, at 100°C and 700 RPM, with 4A zeolite and CaCl2 solution for 8 hours. In the analytical procedure, the kaolin waste, metakaolin, and zeolites were subjected to scanning electron microscopy (SEM) and X-ray diffraction (XRD). The micrographs of the zeolites confirmed the presence of cubic morphology, which is characteristic of type A zeolites. The diffractograms, based on the consulted data sheets, confirmed the presence of zeolitic crystals, as observed in the SEM. Thus, kaolin waste proved to be a viable material for the formation of type A zeolitic crystals, which exhibit ion exchange properties, confirmed by the formation of 5A zeolites.

Abstract:

In this work, were carried out characterizations physical (particle size distribution by sieving, specific mass determination by gas pycnometry and specific surface area by BET), mineralogical by X-ray diffractometry and chemical (X-ray fluorescence and optical spectroscopy of atomic emission with inductively coupled plasm) of a tailing sample from the Li ore flotation stage of a mining company, located in the Campo das Vertentes-MG. The particle size distribution curve of the sample showed that its P80 was 246.7 µm, specific mass equal to 2.72 g/cm3 and specific surface area of 0.45 m2/g. The majority minerals identified were feldspar (albite and microcline), quartz and muscovite. The Li-bearing minerals in smaller proportions were spodumene and lepdolite. The results of the granulochemical analysis showed higher grades of Fe2O3 in the -75 µm size fraction compared with size fraction + 75 µm. The opposite occurred with the Li2O. However, as the overall Fe2O3 content was 0.23%, this material is intended for the ceramics industry

Abstract:

Controlled porosity is a property of interest for studies in applications such as filters, catalysts, absorbers. In materials processing, the freeze casting technique offers great versatility of parts to be produced in relation to the dimensions, type of materials and structural characteristics of the porous cavities formed. In this work, mixed nickel-zinc ferrite was used as a solid filler for colloidal suspension as a precursor to freeze casting processing. The macro and micro porous structures formed during processing were investigated using the Archimedes Method and Scanning Electron Microscopy (SEM) seeking to compare characteristics obtained by varying three polymeric ligands, PEG-400, 1500 and 4000 with a concentration of 4%. High porosities were observed, around 70% for the three samples and the SEM images revealed a structure typical of freezing at high cooling rates, in addition to the more pronounced columnar structure of interest and wider and more homogeneous pores in the sample with PEG- 4000, although the three variations presented the structure satisfactorily.

Abstract:

With the growing concern about waste disposal and its negative impact on the environment and sustainability, the substitution of some materials by biopolymers is becoming increasingly common, as they provide the same properties with faster degradation. However, studies indicate that when this degradation occurs in an alkaline ambiences, it can be even faster. In this study, thermal and mechanical analyses were performed on samples of poly(lactic acid) that underwent degradation in soil with the addition of steel slag to verify the effectiveness of slag as a degradation accelerator. Thus, tensile tests were carried out on samples with different degradation times and conditions (in common soil and in soil modified with steel slag), as well as thermogravimetric analysis (TGA). It was possible to observe variations in their mechanical and thermal properties as an indication of an acceleration in their decomposition time.

Abstract:

Mortars are composite materials that use natural resources in their constitution, such as natural river sand, as fine aggregate, and cement, as a binder. The use of natural aggregates has been causing a series of environmental damages throughout the world, which has encouraged research aimed at using new materials to replace natural aggregates. The objective of this research is to evaluate the potential for incorporating spodumene to replace sand, which is a natural aggregate. Mortars were manufactured in different replacement levels (0, 25, 50 and 1005), in which technological properties were evaluated in the fresh state, such as consistency, water retention and incorporated air content, and in the hardened state with mechanical resistance to compression and flexion, all in accordance with Brazilian technical standards. The results showed that replacing sand with spodumene, which is a waste material, presented satisfactory results, with little influence on the consistency of the mixtures, and improvement in some levels of mechanical properties. Thus, it can be concluded that there is evidence of potential application of this mineral residue in mortar applications, requiring further technological analysis

Abstract:

Composite materials have emerged from the industry's need for materials with superior mechanical performance compared to conventional materials, coupled with concerns about sustainability. The use of waste from mining industries constitutes raw materials that can be used in the composition of these materials. The objective is to produce composite materials with a polymer matrix and kaolin waste as a filler. The composites were manually produced using silicone molds, following ASTM D638-2014 and ASTM D790-2017 standards. Subsequently, mechanical tests were conducted to evaluate the material's mechanical properties. In the tensile test, tensile strength, Young's modulus, and deformation were analyzed, while in the flexural tests, flexural strength and elasticity modulus were evaluated. Accordingly, for tensile strength, the composition with 15% kaolin waste addition showed the highest tensile strength, highest Young's modulus, and lowest deformation. For flexural strength, the composition with 10% waste showed the highest flexural strength and elasticity modulus. It is concluded that the study of waste added to the polymer matrix presents good mechanical characteristics, making them promising for the development of new materials.

Abstract:

Brazilian coffee is widely exported, mainly to the European Union, the United States, and Japan, and is extensively used in various food markets. During coffee processing, residues such as immature coffee beans, husks, and grounds are generated, which can be used in the manufacturing of composite materials. These residues can be better utilized in a circular economy, contributing to sustainable development. This study proposes the fabrication of a composite with a polymer matrix and coffee grounds, aiming to evaluate its mechanical properties and mitigate environmental impacts. The results show that the tensile strength of the composites with 5%, 10%, and 15% coffee grounds is lower than that of the pure matrix, with a trend of decreasing strength as the proportion of residue increases. The sample with 10% coffee grounds exhibited significantly lower performance. This is due to the agglomeration of particles, which acts as a starting point for cracks, weakening the composite. The ANOVA confirmed that the calculated F values for tensile strength, modulus of elasticity, and deformation exceed the critical values, rejecting the equality among the mean properties at a 5% significance level.

Abstract:

Geopolymers are alkaline-activated polymeric inorganic materials, which stand out for their potential to use industrial by-products as raw materials, which significantly contributes to environmental and economic sustainability. One of the main focuses of research in the area is the use of fly ash, a by-product of electrical energy generation, as a precursor in the production of geopolymers due to its composition rich in silicates and alumina and its low cost. With this opportunity, this study addressed the use of fly ash as a precursor rich in aluminosilicates for the manufacture of geopolymers with alkaline activation based on sodium hydroxide and silicate, evaluating molarity variations. To characterize the fly ash, FRX, DRX and fire loss tests were used. The variation in geopolymer molarity was evaluated by the compressive strength test. Fly ash was found to be rich in aluminosilicates in the XRF test, a prerequisite for its use as a precursor in geopolymers. XRD revealed a high degree of amorphism. Fire loss was less than 2%. The compressive strength test revealed an increase in strength with an increase in the molarity of the activating solution.

Abstract:

THE STUDY INVESTIGATED THE SIMULATED TRANSMISSION FACTOR OF DEPLETED URANIUM DIOXIDE FOR GAMMA RADIATION SHIELDING. DEPLETED URANIUM DIOXIDE IS A DENSE AND SLIGHTLY RADIOACTIVE MATERIAL, MAINLY COMPOSED OF URANIUM-238, USED IN VARIOUS MILITARY APPLICATIONS, ESPECIALLY IN ARMOR-PIERCING AMMUNITION. HOWEVER, IT ALSO HAS CIVIL APPLICATIONS, SUCH AS IN RADIATION SHIELDS IN MEDICAL FACILITIES, COUNTERWEIGHTS IN AIRCRAFT AND SHIPS, RADIATION PROTECTION IN SHIELDING, AND STABILIZERS IN CONSTRUCTION. THE STUDY DEMONSTRATED ITS EFFECTIVENESS FOR SHIELDING GAMMA RADIATION FROM CESIUM-137 AND COBALT-60.

Abstract:

The constant search for efficiency in the construction industry drives a continuous process of innovation, both in materials and construction methods. This movement aims not only to promote the durability of structures, but also to find ways to reduce costs and mitigate environmental impact. This study focused on evaluating the physical and mechanical properties of Extruded, Pressed and Burnt Ceramic Fitting Blocks (BCEPQ). The BCEPQ were evaluated according to Brazilian standards, covering geometry, water absorption and compressive strength. For its production, the clay was processed by extrusion (WD36 extruder) and pressing (Eco Máquinas 7000 Turbo II), followed by drying and firing in a Vault-type oven. The results indicated geometric compliance with tolerances established by the Brazilian standard. Water absorption was 18.32% (± 0.35), meeting the standards for the VED40 class of sealing blocks (8% ≤ AA ≤ 25%) and the EST40 structural class (8% ≤ AA ≤ 21 %). The compressive strength was 22.33 MPa (± 1.49), exceeding the limit of 4.00 MPa for VED40 and EST40 blocks. It is concluded that the BCEPQ produced meets the normative standards of dimensional analysis, physical and mechanical properties, for sealing and structural blocks.

Abstract:

Hydroxyapatite is a multifunctional ceramic that can be used in implants due to its good biocompatibility, osteoconduction and bioactivity, in addition to being non-toxic and allowing easy replacement of cations and anions. It also has high relevance in the environmental area, being used in catalysts and filters. In both cases, porous structures are sought and methods of producing these structures are constantly developing. This work aims to compare the use of PEG-4000 and PEG-6000 as a ligand at a concentration of 4%wt. To improve the rheological behavior, the pH of the water was adjusted to 11.8 using NaOH. The samples were frozen, freeze-dried and sintered at 1150 °C for 6 hours. The morphology of the pores was characterized using Scanning Electron Microscopy (SEM) analyzes and the apparent porosity using the Archimedes method. PEG-4000 presented greater homogeneity in pore size while PEG-6000 presented a more pronounced and well-defined structure. The apparent porosity found for PEG-4000 was 51.03% and for PEG-6000, 49.11%.

Abstract:

The main objective of this study was to evaluate how the inclusion of waste sludge, generated in the flat glass cutting and polishing process, influences water absorption, linear shrinkage, and mechanical strength of red ceramics produced from a clay mass that incorporated 5% coffee husk. Starting from the base formulation with 5% coffee husk, glass sludge was incorporated in different proportions: 5%, 15%, and 25% by weight. By extrusion, specimens with standardized dimensions of 110 mm x 30 mm x 20 mm were manufactured and subjected to firing cycles at temperatures of 800°C and 900°C. Subsequently, tests for water absorption, linear shrinkage, and compressive strength were conducted. The results obtained showed that the glass waste has significant potential to be used as a component in clay body formulations, mitigating the deleterious effect of the coffee husk. Standing out for its ability to reduce water absorption and increase the mechanical strength of ceramics, it suggests promising opportunities for the sustainable use of this waste in the production of enhanced ceramic materials

Abstract:

Despite the excellent biocompatibility of titanium (Ti) implants, their biological inertia does not generate a chemical bond with bone tissue. To improve the performance of Ti implants, researchers are developing bioactive surfaces that promote adhesion, proliferation and differentiation of osteoblasts and chemical bonding with the newly formed tissue. The incorporation of biologically relevant ions into the structure of hydroxyapatite (HA) increases biological activity, biocompatibility and more. Magnesium (Mg), essential for bone growth, when incorporated into HA, can alter the mechanical properties of bone. Studies show that the concentration of Mg in HA affects the physicochemical properties of the coating and the morphology of the crystals. Doping HA with silicon (Si) improves bone repair, vascularization and coating morphology, despite increasing roughness after annealing. Ti implants coated with HA replaced by Si (Si-HA) improve cell proliferation and osteogenic and angiogenic differentiation, while inhibiting osteoclastogenesis. The aim of this literature review is to present hydroxyapatite co-substituted with Si and Mg (HA-Mg-Si) as a bioactive surface option. HA-Mg-Si shows promising potential in bone repair, but studies are needed to optimize its formulation for specific clinical applications.

Abstract:

Foram investigadas as características gerais e propriedades tecnológicas de quatro tipos de argilas obtidas de um mesmo local no norte do Estado do Rio de Janeiro, Brasil. Essas argilas são destinadas para aplicações em cerâmicas como tijolos e telhas. As argilas foram primeiramente analisadas por difração de raios X, composição química, distribuição granulométrica, análise térmica e plasticidade. Amostras extrudadas foram queimadas em temperaturas variando de 850 a 1100ºC para determinar a retração linear, absorção de água e resistência à ruptura flexão. Os resultados mostraram que três das argilas estudadas apresentam características adequadas para a fabricação de tijolos. No entanto, para duas dessas argilas adequadas é necessário adicionar materiais convenientes para aumentar a trabalhabilidade. A alta porosidade desenvolvida após a queima dificulta o uso dessas argilas para telhas. Isso é consequência da natureza caulinítica das argilas, bem como de sua elevada perda ao fogo.

Abstract:

This work aims to evaluate the influence of the incorporation of mud from the cutting of flat glass on the physical and mechanical properties of a clay ceramic used in civil construction. The raw materials were characterized by DRX, FRX, particle size by sieving and sedimentation, plasticity. Formulations were prepared with different percentages of waste addition, and then specimens were produced by uniaxial pressing, and fired at 900 and 1000ºC. After burning, the properties of RL, AA, and TRF were evaluated. With the results, it was observed that the incorporation of glass waste had a positive effect on the sintering of ceramics and on the properties of the fired specimens.

Abstract:

The objective of this work was to incorporate water treatment plant sludge from the decantation and filtration stages, evaluating the effect on the properties of fired ceramics. The sludge was characterized by FRX, DRX, and particle size distribution. Different formulations were prepared with up to 10% by weight of the waste added to a ceramic mass, and specimens were produced by extrusion and fired at different temperatures. This type of mud has a mineralogical composition similar to the floodplain clays used in red ceramics, being predominantly composed of kaolinite. The high fire loss of the sludge can be attributed to the presence of organic matter as well as the hydroxyl groups of kaolinite, gibbsite and goethite. Sludge does not bring real benefits to ceramics, but in a controlled quantity, adding the residue can be a viable alternative, in addition to being a correct way of disposing of this waste

Abstract:

This work aims to evaluate the effect of incorporating up to 30% by weight of packaging glass powder, in different particle sizes, on the plasticity of kaolinite clay used to manufacture bricks and tiles. Different formulations were prepared with the elimination and plasticity of the masses tested by the methods of Atterberg and Pfefferkorn. With the results obtained, it was possible to conclude the beneficial effect of glass waste in smaller particle sizes on the workability of handmade ceramic mass

Abstract:

With the increase in demand for construction, the use of alternative construction materials is gaining ground in the market every day. Therefore, aiming to reduce the consumption of cement and, consequently, the emission of carbon dioxide, the present work sought to use limestone filler and quartz powder as substitutes for cement in the production of mortar. The waste used in this research is by-products of mining and industry, and is normally discarded as urban solid waste (MSW). The main objective of this work was to study the rheology for possible reuse and application of the residue. Spreading, mass density, incorporated air content and squeeze-flow rheology tests were carried out. The results found were satisfactory and, in general, met regulatory requirements.

Abstract:

Agroindustry plays a fundamental role in the Brazilian economy. However, the waste generated negatively affects the ecosystem, resulting in considerable environmental damage. In response to this challenge, there is a growing search for techniques that aim to reuse waste from this industry, aiming for more effective management. Among the alternatives explored, natural fibers, such as coconut and açaí waste, have received prominence in several sectors, due to the benefits they provide in different matrices. However, these untreated fibers have properties that require treatment to improve their applicability. In this study, the characteristics of untreated coconut and açaí fibers were analyzed and treated with tannic acid at a concentration of 5%, in a ratio of 1:20. In this direction, sample characterization studies were carried out using scanning electron diffraction (DRX), crystallinity index and wettability. The results demonstrated that the treated fibers had a higher crystallinity index and a lower wettability angle, indicating greater hydrophobicity after surface treatment. This characteristic suggests that treatment with tannic acid can expand the possibilities of application of these fibers in sectors that require less hydrophilicity of these materials, promoting greater efficiency in the use of agro-industrial waste.

Abstract:

Natural lignocellulosic fibers have the potential to be used as sustainable materials in the construction industry in geopolymers due to their improvements in properties such as tensile strength, flexion and for making the compounds lighter. In this context, there are açaí fibers, which are obtained after using the pulp and require final disposal and generally end up in landfills. Thus, the objective of this work was to produce geopolymeric compounds reinforced with açaí fibers and evaluate the properties of geopolymeric mortar reinforced with the addition of açaí fibers at 1 and 2% without treatment and treated with NaOH at a concentration of 5 and 10% per through compression resistance and flexural resistance tests, in addition to water absorption of the fibers. The results showed that the addition of 2% açaí fibers treated with 5% NaOH presented the best results in compressive and tensile strength, indicating that the alkaline treatment was effective in removing amorphous components and consequently improving the fiber-geopolymeric matrix interaction. Thus, the geopolymer with the addition of açaí fibers has potential for application in the civil construction segment as a sustainable material.

Abstract:

The red ceramic industry is associated with various environmental damages, from the extraction of natural resources as raw materials to the generation of high amounts of waste. This study proposed the reuse of ceramic waste, which is obtained by burning ceramic blocks, at a temperature of 600°C to 630°C. To transform the ceramic waste so that it could be used in mortars, a crusher was used, such as a ball mill with one hour of grinding time. Multiple-use mortars were made in the composition 1:6 (cement:sand), for laying blocks and covering ceilings and walls, replacing sand with ceramic residue in proportions of 10, 20 and 30% and the reference and use trace of CPII-E RS and CPV ARI cements. In order to analyze the viscosity and flow of the mortar, a rheology test was carried out. The squeeze-flow test is a method that evaluates the behavior of the mortar in relation to the applied load and the deformation caused. The results show that the mixes with 30% of ceramic residue presented greater displacements and better workability indexes and over time the displacements were reduced.

Abstract:

Mortar plays an essential role in construction, providing impermeability, stability, and various applications such as bricklaying, waterproofing, and surface finishing. The population growth has led to a significant increase in construction activities, resulting in higher generation of solid waste. In this context, expanded polystyrene (EPS), commonly known as Styrofoam, has been increasingly used in construction due to its unique properties and its potential to reduce environmental impact by utilizing it as raw material for construction. Therefore, this project aims to analyze and test the general characteristics of mortar when EPS is added to its composition. The conducted tests will serve as a basis to evaluate the feasibility of incorporating expanded polystyrene and determine the appropriate proportions for its use. Additionally, the project aims to reduce environmental impact by proposing an implementation method for EPS in the construction industry

Abstract:

The quality of the mixing water is crucial to guarantee the properties and quality of cementitious materials. Water plays an essential role in the mixing of aggregates and in the hydration processes, so it is essential that it complies with regulatory criteria. Studies demonstrate the negative effects of impure water on concrete, including interference with resistance, staining and changes in the cement's setting. NBR 15900-1 establishes verification parameters, maximum limits for contaminant concentrations and test procedures for determining water quality. The adoption of adequate quality standards is essential to prevent pathologies, such as corrosion of reinforcement, highlighted by studies. The present work aimed to evaluate the behavior of mortars using contaminated water containing 5% chlorides, and another with 5% hydroxides in its compositions. To this end, the consequences and applications of contaminating compositions were evaluated in the criteria of consistency, water absorption, compressive strength in 7 and 28 days, and pH analysis of the specimens. It can be concluded that the addition of contaminated kneading water in sample preparation led to a significant drop in compressive strength when compared to the reference sample. It was observed that the composition containing chloride absorbed more water and consequently had its compressive strength at 28 days compromised by more than 95%. As evidenced by studies, chloride, in concentrations outside the recommended limits, presents an exponential reduction in the performance of cementitious materials, enabling the emergence of pathologies and potentially compromising the interim use of the structure. Finally, the continued importance of evaluating and guaranteeing the water standards required for the adequate production of these materials is highlighted.

Abstract:

The peri-implant ligament is a crucial physiological adaptation resulting from the process of osseointegration, which involves the implantation of osseointegratable implants in gnathic bones. During bone regeneration, various proteins from the extracellular matrix and blood plasma adsorb, forming a provisional matrix that acts as a scaffold for the bone matrix at the bone-implant interface. Implants made of commercially pure titanium (grades II and IV) and the titanium-aluminum-vanadium alloy (Ti-6Al-4V) promote bone formation and remodeling through the adsorption of proteins on the implant surface. The hierarchical interaction between bone, cells, proteins and the implant are essential for the development of the peri-implant ligament, which occupies the osteoconduction space and creates an adaptive interface between the alveolar periosteum and the implant. Although it plays a role like that of a basement membrane, the osteoconduction space does not have the same embryonic origin, acting as a functional substitute. This ligament is fundamental to the integrity and stability of the implant, distributing masticatory loads and preventing fractures. The aim of this literature review is to address the presence of the peri-implant ligament, from the osseointegration process onwards, because of the interaction between cells-proteins-implant in the osteoconduction space

Abstract:

Geopolymers are an innovative and promising alternative, especially in the construction industry, offering superior mechanical properties compared to conventional cement, along with greater environmental preservation and reduced ecosystem impact. Geopolymers are characterized as a ceramic material made up of semi-crystalline aluminosilicates. Geopolymers are characterized as a ceramic material formed by semicrystalline aluminosilicates, derived from industrial waste and alkaline reagents. These ceramic materials have a structure like that of zeolites and feldspars. They exhibit a structural organization analogous to polymer chains during the curing process, as well as binding properties like Portland cement. Notably, they demonstrate high performance in pastes and concretes with low CO2 emissions and can be used for encapsulating toxic and radioactive waste. Their versatility and potential to reduce environmental impact make them a sustainable choice for the construction industry, driving more efficient and responsible practices within the sector. By recognizing the value of these materials, it is possible to envision a future where construction adopts more eco-friendly solutions, promoting more balanced and conscious development. This work aims to present the structures and properties of geopolymeric cements.

Abstract:

The use of structural masonry as a structural solution and construction method has received increasing attention in recent years in Brazil, particularly in the northern region of the state of Rio de Janeiro, as it is a more rationalized and economical construction system. In a bibliometric evaluation in the “Scopus” database between 2013 and 2023, 10,386 results were found with the keyword “Structural Masonry”, thus confirming the great importance of the topic in question. In the present work, the mechanical resistance to simple compression, the water absorption rate and the dimensions of blocks used by a construction company in the municipality of Campos dos Goytacazes in four-story social housing works were evaluated. The results indicate an average compressive strength of "6.13 ± 1.15 MPa", characteristic compressive strength of 4.60 MPa, a water absorption rate of "13.71 ± 0.54" % and dimensional variations of less than 4mm. Laboratory analyzes indicate satisfactory quality within the parameters established for constructions of up to 4 floors.

Abstract:

The search for sustainability in the conscious use of materials in civil construction makes the application of renewable resources an increasingly necessary necessity. One of the biggest challenges today is social and economic development, while maintaining environmental preservation. Plastic waste has attracted a lot of attention because it generates direct negative impacts on the environment, the material takes around 400 years to decompose in nature. In order to provide an adequate destination for this waste, this work aimed to evaluate the partial replacement of natural fine aggregate with crushed PET (polyethylene terephthalate), evaluating feasibility and resistance. Four mixes of concrete were obtained, one with natural fine aggregate and the others with different proportions of amber PET bottle, replacing 10%, 20% and 40% of the fine aggregate with PET. For this, a case study was carried out using 20 concrete specimens, divided equally into 4 groups, group A is conventional concrete, group B is concrete with 10% PET added, group C is concrete with the addition of 20% PET and group D is concrete with the addition of 40% PET. The samples were subjected to compressive strength, diametral compression tensile and slump tests. From the results obtained in the mechanical tests, it is concluded that the partial replacement of natural fine aggregate (sand) by PET can be added to concrete for non-structural purposes, whose purpose does not require high resistance, such as: curbs, blocks and floors. Therefore, PET in concrete is a viable form of disposal and helps solve a serious environmental problem related to the accumulation of PET bottles in landfills.

Abstract:

The growing demand for sustainable materials has driven research into polymer composites reinforced with natural fibers. This work investigates the behavior of polyurethane matrix composites reinforced with broomcorn (Sorghum bicolor) stalks in different volume fractions under compressive forces. A polyurethane resin based on castor oil and stalks donated by independent producers were used. The composites were molded, cured, and cut according to ASTM D695 standards, and subjected to compression tests. The results showed that the compressive strength increased with the volumetric fraction of stalks, with values ranging from 3.97 MPa to 6.01 MPa. ANOVA analysis confirmed statistically significant differences between reinforcement levels. The specific compressive strength also followed the same trend, validating the effectiveness of broomcorn as a reinforcing material. It was concluded that the incorporation of broomcorn stalks not only improved the mechanical properties of the composites but also contributed to environmental sustainability, offering a viable solution for the use of stalks.

Abstract:

Aramid is a high-performance material already well-established in the market for various applications, prominently featuring in the use of components subjected to ballistic conditions. Polymeric composites reinforced with aramid fabric also demonstrate a significant ability to absorb energy when subjected to ballistic tests. From the perspective of composite material development, it is known that, in addition to the properties exhibited by the constituent phases, matrix and reinforcement, the type of arrangement, their disposition, distribution, as well as the volumetric fraction of each phase, are determining factors in the properties exhibited by the material. In this context, this study investigates the influence of two types of configurations, employing a simple arrangement of aramid fabric as reinforcement in an epoxy matrix composite, in order to compare their abilities in energy absorption. The configurations of the aramid fabric used for comparison are as follows: stacking layers of the fabric following the same orientations, in other words, with fibers oriented at 0°/90° in all layers; and alternating layers of the fabric with angles of -45°/0°/45°/90°. For the ballistic tests, high-energy 7.62 mm caliber ammunition was used. The obtained data were statistically processed using analysis of variance (ANOVA). Ballistic parameters such as limit velocity and deformation cone area, as well as prevailing failure mechanisms under both conditions, were investigated.

Abstract:

After water, coffee is the most consumed beverage in the world. Because it is produced and sold in abundance, it generates a significant amount of waste which, when not disposed of correctly, causes environmental damage, because when it comes into contact with the soil, it produces gases that are harmful to the environment. Because of this characteristic, coffee grounds, which are the waste after the coffee has been brewed, have been evaluated so that they can be reused in a way that causes less environmental damage. This work aims to characterize this material in order to detect its functional groups and assess its chemical composition using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis to check whether it can be used in polymer composite matrices. In addition to these, the density was checked using liquid pycnometry, which was evaluated after a saturation period of 10 days. The analyses showed positive results for its use in polymer composites.

Abstract:

The increase in resource consumption in search of a better quality of life raises concerns about the sustainability of human actions. In this context, composites made from industrial waste emerge as sustainable and economical alternatives to this problem. In this sense, this study aims to evaluate the addition of crushed red ceramic waste (chamote) into an epoxy matrix, as well as its influence on impact resistance. The epoxy system Bisphenol A diglycidyl ether/Diethylenetriamine (DGEBA/DETA) was used, in a proportion of 16/100 resin/hardener. Formulations with 0, 10, 20 and 40% chamotte volume were tested. The impact tests followed the Charpy method of ASTM D6110, with a 15 J hammer. The results indicated that the addition of particles does not result in significant variations in resistance up to 20%, while in the formulation with 40% there was an increase of 7.5%. This suggests possible improvements in performance, cost reduction and socio-environmental impact.

Abstract:

In composite materials, the use of lignocellulosic fibers as reinforcement is a sustainable, low-cost alternative with significant mechanical properties compared to synthetic fibers. The objective of this study was to develop composite materials through the manual manufacturing method, with an orthophthalic polyester matrix using reinforcement from açaí, curauá and hybrid lignocellulosic fibers to perform morphological analyzes of fracture surfaces. The mass fraction values used in the composites were 50% fiber, 50% resin and 1% catalyst, and for the hybrid composite they were 25% açaí fiber and 25% curauá fiber to 50% resin. polyester. To this end, fiber density testing and morphological analysis of the fracture surface of the composites were carried out through microscopic analysis of the specimens, using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). The analyzes showed that the composites presented good fiber/matrix interfacial adhesion, observed by the rupture of the fibers and the presence of few bubbles, thus demonstrating the potential for satisfactory mechanical behavior, being suitable for carrying out mechanical tests and future applications.

Abstract:

This article investigates the impact of incorporating natural fibers on the mechanical properties of polyester matrix composites through tensile test and SEM analysis. The results show that composites without fibers have a tensile strength of 46.940 MPa. The addition of 5%, 15%, and 25% fibers results in strengths of 40.967 MPa, 43.020 MPa, and 34.073 MPa, respectively. ANOVA confirms significant differences between the composite groups (p < 0.05). The tensile modulus was 1.077 GPa for composites without fibers, 1.102 GPa with 5% fibers, 1.127 GPa with 15%, but decreased to 1.010 GPa with 25% fibers. The initial strain decreased from 0.05515% (0% fibers) to 0.04449% (5% fibers), stabilizing at 0.04515% with 15% fibers. The study concludes that adding natural fibers can improve tensile properties up to an optimal point; adding fibers in volume fractions below and above 15% requires treatments to enhance fiber-matrix.

Abstract:

There is great environmental concern due to the volume that is generated and the final destination of industrial waste, as these are deposited in landfills and dams which, in addition to occupying a large area, can contaminate the soil and rivers, triggering a series of problems for the environment and risks to human health. The objective is to develop an artificial stone incorporating iron ore. The artificial stone plates were developed through compression and the iron residue was characterized and the artificial stone plates produced were evaluated for their physical index, chemical and mechanical attack. The rupture stress value obtained was 34.86±3.93 MPa, water absorption was 0.21%, obtaining a high quality and the most aggressive reagent was hydrochloric acid, which resulted in a greater loss of mass. 0.14±0.22%. The developed artificial stone proves to be a viable alternative

Abstract:

The construction sector is a major consumer of natural resources, leading to adverse environmental impacts due to increased consumption of cement and aggregates. Geopolymeric materials emerge as more sustainable alternatives, offering superior mechanical and thermal properties, as well as lower emissions of polluting gases. However, the manufacturing process of these materials still involves the use of industrial activators, which contribute to the emission of harmful gases into the environment. The use of agroindustrial waste as a binder has gained prominence in scientific research due to its potential to improve properties and reduce environmental impact. Among these residues, corn straw ash (CSA) emerges as a viable yet underexplored alternative in the literature. In this context, this paper aims to evaluate the effects of adding CSA, with different thermal curing periods, on fresh and hardened geopolymer pastes. The results indicate that increasing the binder content in the geopolymer formulation led to a noticeable increase in viscosity. Furthermore, the inclusion of CSA in different proportions and thermal curing periods did not significantly affect density values, while proportionally increasing compressive strength

Abstract:

Nowadays, there is a constant concern to develop products that are environmentally friendly. This is largely due to the constant threat of oil shortages, the emission of greenhouse gases and inadequate waste disposal. In view of this urgency for the development of alternative products to those of synthetic origin and increasingly sustainable, composite materials reinforced by vegetable fibers have emerged, consisting of a polymeric matrix and reinforcement, the latter of natural origin. The use of polymer composite materials reinforced by natural fibers has advantages and disadvantages. The main advantages are the greater lightness of this material, the reduction of greenhouse gas emissions and the reduction of the carbon footprint. And as disadvantages, they present poor interfacial adhesion between the matrix and fibers and high moisture absorption. The study of these advantages and disadvantages makes it possible to investigate properties in the natural fiber composite based on technical standards, such as ASTM D3039 used for the tensile test of the material, thus obtaining resistance and elastic modulus values. Therefore, promising results in the use of natural titic vine fiber as reinforcement in epoxy matrix polymer composites were obtained, showing an improvement in tensile strength with the incorporation of natural fiber into polymer resin, mainly for the volumetric fraction of 70% of reinforcement.

Abstract:

The manufacture of conventional Portland cement results in high CO2 emissions, contributing to environmental problems. Given this, the construction industry is looking for more sustainable materials, such as geopolymers, which use industrial waste and have been explored as an alternative. This study investigates the incorporation of pineapple fibers into the geopolymer matrix, aiming to improve the mechanical properties of the material. The fibers, coming from agro-industrial waste, after treatments in high concentrations of NaOH, are integrated into the geopolymeric mortar, and can act as a crack bridge in order to provide greater resistance and ductility to the fragile matrix. The test results indicate increases in compressive and flexural resistance and a reduction in the brittle behavior of the matrix, highlighting the potential of these fibers in the production of more sustainable construction materials.

Abstract:

In the current global context, the pursuit of cost reduction and increased productivity drives the development of materials with enhanced specific properties. Polymer composites, increasingly recognized as a solution to these demands, stand out for their use of plant fibers due to their abundance, low cost, and renewable origin. Curauá (Ananas erectifolius), native to the Amazon region, is renowned for its natural fibers with high mechanical strength. Scientific research has been exploring the potential of these fibers as reinforcement in polymer matrices, aiming to replace imported synthetic fibers. The properties of composites are influenced by the individual characteristics of their components, and mechanical tensile tests were conducted to ascertain these properties, following ASTM D638-14 standard guidelines.

Abstract:

The development of synthetic materials to replace natural materials can result in products with better technological properties and represent a reduction in the exploitation of natural raw materials. Artificial rocks are synthetic materials with higher properties than their natural counterparts and which are mostly produced from solid waste. Therefore, the present work aims to produce and characterize an artificial rock using FGD steel waste and an epoxy resin matrix. The rock was produced using the vacuum vibro-compression method and characterized for its physical and mechanical properties. The rock was classified as having very high flexural strength, exceeding the standard required resistance by more than three times. Shore hardness revealed a hardness close to that of other materials produced with the polymer matrix.

Abstract:

Natural fibers have contributed positively to sustainability, especially when collected and used in a way that minimizes environmental impacts. These are normally acquired through socially responsible methods, guaranteeing income generation for forest people, working conditions and social well-being. Natural fibers have often been replacing synthetic fibers as they are biodegradable, easy to acquire, low cost and have potential for use in circular economy processes. In recent years there has been an increase in the popularity of natural lignocellulosic fibers (NLFs) among academic researchers and companies. This is related to the unique properties that make them suitable for a variety of applications such as reinforcement for composites, biomaterials, cellulose nanomaterials, activated or conductive carbon and others. With the aim of further studying the chemical-structural characteristics of a little-known Amazonian fiber, the titica vine fibers (Heteropsis flexuosa), this work characterized the fiber before and after treatment with sodium carbonate using the Fourier-transform infrared spectroscopy (FTIR) technique. The results indicated characteristic bands of lignocellulosic materials and the presence of fundamental functional groups belonging to the main constituents of the fiber. Furthermore, after treatment, a decrease in the intensity of the adsorption bands referring to groups related to lignin and hemicellulose was observed.

Abstract:

Demolition waste is waste composed of debris, coming from structural elements, rubble and renovations. Its potential has been the subject of study by researchers who observed that through heat treatment it is possible to promote dehydration, forming hydrated calcium silicates, which when in contact with water again, are capable of partially recovering the strength of the cement matrix. For this reason, this work analyzed the physical-mechanical characteristics of Plaster Cement Residue (RCR) dehydrated at 550°C and crushed, through laser granulometry, X-ray Diffraction (X-RD) and isothermal calorimetry analyses. Once in the hardened state, prismatic specimens (4x4x16) were made for testing density, mechanical resistance, void index and water absorption by capillarity and immersion. The mixture developed was 1:6 (cement:sand), with replacement proportions of 0, 10, 20 and 30% of the fine aggregate by RCR and CPV ARI cement was used. The results showed that replacing sand with RCR promoted significant improvements in the mechanical and technological properties of the mortar, increasing mechanical resistance, reducing the void index and absorption both by capillarity and immersion.

Abstract:

This study investigated the influence of the type of curing on the compressive strength of mortars based on Portland cement with the addition of gypsum by-product, obtained during the production of lactic acid. Mortars were made with the addition of gypsum by-product, ground for 30 minutes in a ball mill, in proportions of 0%, 2.5%, 5% and 7.5% in relation to the cement mass and cured at room temperature and submerged. in water saturated with lime. The compressive strength of the mortars in both types of curing was evaluated, as well as microstructural analysis by X-ray diffraction. The results showed that samples subjected to ambient curing presented greater resistance compared to those subjected to curing immersed in lime-saturated water. However, mortars with the addition of calcium sulfate up to 5% and immersed curing showed significantly higher compressive strength than the reference mortar. While, in air curing, the resistance showed a decreasing trend with the addition of gypsum. This indicates that the curing regime has a significant impact on compressive strength, but does not alter the type of hydration products.

Abstract:

The current scenario drives interest in the development of ballistic vests. Advances in the field have resulted in the production of vests using high-performance synthetic fibers such as Kevlar® and Dyneema®. These materials, however, are costly and present environmental challenges. Natural fibers, such as sisal, emerge as a sustainable alternative due to their unique characteristics. However, their inherent heterogeneity poses considerable challenges to reliability, particularly in ballistic applications. Therefore, it has been proposed to combine synthetic and natural fibers in a hybrid composite to balance high ballistic performance and low cost. The properties of a composite can vary according to the configuration of the reinforcement layers, thus, the present study sought to evaluate five different stacking sequences of sisal and aramid fabric layers in an epoxy matrix hybrid composite through residual velocity tests. It was found that samples made entirely of sisal presented the highest specific energy absorption in relation to thickness (143.06 J/cm), promoting a cost saving of 93,4% compared to the composite made only of aramid. Furthermore, it was also found that hybrid samples perform better than samples composed entirely of aramid, meaning that the inclusion of sisal in the composite does not reduce ballistic performance.

Abstract:

Composites with natural lignocellulosic fibers (NLFs) currently have extremely diverse applications, including in engineering industries, due to their lower cost and density, as well as ease of processing. Another notable material, graphene oxide, has attracted considerable attention for its properties, mainly as a coating to improve interfacial adhesion in polymer composites. Therefore, this research focuses on investigating the dynamic mechanical (DMA) and thermomechanical analysis (TMA) for epoxy matrix composites containing 30% by volume of CM reed fiber incorporated with graphene oxide. Compared to the control group (untreated epoxy) the damping factor (Tan δ), being the ratio of the loss modulus under storage, is significantly increased from (0.55-0.75) for the composites reinforced with 30% of CM reed fibers incorporated with graphene oxide. The Tg found at 127°C for condition 30 FJGO/EP was higher than the other EP conditions, 30 FJ/EP and 30 FJ/EP-GO, as well as the coefficient of thermal expansion (208.52 to 248.95 x 10−6/°C). The mass loss for the 30 FJGO/EP condition in the first stage was slightly higher than the EP condition (1.63%). These DMA and TMA results prove to be promising.

Abstract:

Natural fibers have emerged as a promising alternative to synthetic fibers in composites, due to their favorable mechanical properties and sustainability. This study investigates the tensile behavior of epoxy composites reinforced with different levels of ramie fiber, a high-strength lignocellulosic fiber. The tensile properties of the composites were evaluated by varying the amount of lignocellulosic fibers. Composites containing up to 30% by volume of long, continuous and aligned ramie fibers were tested on an universal testing machine at room temperature, and the fracture surfaces were analyzed by scanning electron microscopy (SEM). The results show a significant increase in the mechanical properties of the composites with increasing fiber content. The results of the tensile test and SEM analysis reveal good adhesion between the fiber and the matrix, demonstrating the potential of ramie fiber as a reinforcement for epoxy composites, with promising applications in various areas, such as the high-performance bicycle industry and its components.

Abstract:

Tensile strength is a fundamental property for various materials, especially those used in structural applications. The use of natural fibers, such as bamboo, as reinforcement in polyurethane composites has been of interest due to their favorable mechanical properties and renewable nature. In this study, polyurethane composites with different bamboo fiber contents were prepared and their tensile strength was evaluated. It was possible to observe an equivalence among the results of each of the proportions used, offering the perspective that the increase in fiber for this study did not improve the properties of the composite. Thus, although the addition of natural fibers may improve certain mechanical properties of polymeric composites, such as perpendicular tensile strength and impact resistance, the modulus of elasticity and tensile strength limit may not experience a significant increase if factors such as fiber orientation, bonding, content, distribution, fiber flexibility, nature, and properties of the matrix are not optimized and compatible

Abstract:

The biodiversity of Brazilian flora offers numerous possibilities for the development of innovative materials. Tauari sawdust, a byproduct of the Amazonian timber industry, has potential for use in composites due to its unique cellular structure. This study presents a morphological analysis of natural tauari sawdust and epoxy resin composites made with 30% by volume of sawdust, along with an evaluation of mechanical performance through tensile tests. The morphological results showed the heterogeneous structure of the sawdust, with a rough and porous surface, significant characteristics for adhesion and interaction with the matrix. Mechanical tests revealed that composites with tauari sawdust exhibited improved tensile properties due to the effective interaction between the components. It is concluded that epoxy resin composites reinforced with tauari sawdust are promising for various industrial applications, combining mechanical strength and sustainability

Abstract:

Industrial activities require base surfaces of exceptional quality, making it essential to select flooring with specific characteristics. These include resistance to wear, discontinuities, cracks and other anomalies. Faced with this requirement, various sectors have opted to use polymeric floor coatings, known as High Performance Coatings (HPC). At the same time, the growing interest in environmental sustainability has driven the search for more ecologically viable materials. In this context, this study focuses on the use of sugarcane bagasse particles combined with epoxy resin to produce a composite suitable for use as a HPSR. Subsequently, a Cost of Goods Sold (COGS) analysis is carried out to assess the econoeded to manufacture the prototypes tested, as well as the volume of material used, both polymeric and lignocellulosic. Although this analysis is still preliminary, it clearly indicates the need to improve the prototype manufacturing process in order to reduce working time. This is due to the fact that high workloads result in an increase in the CMV, making the product relatively expensive for the usual market consumers.mic viability of these materials. The study includes calculating the hours ne This is due to the fact that high workloads result in an increase in the CMV, making the product relatively expensive for the usual market consumers.

Abstract:

This study evaluates the possible anisotropy of mechanical properties in different orientations from the printing platform in tension and flexural tests, specifically elastic modulus and yield strength, for PA12 produced by Multi-Jet Fusion (MJF). Tensile elastic modulus can present differences up to 55 % depending on the orientation of the loading direction to the printing platform. Tensile yield strength, in similar behavior, can present differences up to 75%. In flexural tests, elastic modulus and yield strength can vary by 65% and 45%, respectively. These findings indicate the anisotropic mechanical behavior of PA12 parts produced by MJF. The anisotropic mechanical behavior was related to the functional sintered area per pass, indicating that higher functional sintered areas lead to smaller mechanical properties

Abstract:

Three-dimensional (3D) printing has revolutionized the industry by allowing the rapid creation of complex personalized parts. One of the most used techniques is stereolithography printing (SLA), which uses photocurable resins exposed to a laser for solidification. The application of this technology in the manufacture of intraoral devices, such as mouth guards and occlusal splints, has significant potential, but still lacks detailed studies. The objective of this work is to evaluate the mechanical properties of materials produced by additive manufacturing, comparing them with conventional materials used in the manufacture of mouthguards and occlusal splints. Test specimens were printed using an SLA printer. Shore A hardness and tensile tests were conducted for mouthguard materials, and compression and Shore D hardness tests for occlusal splint materials. In the tensile test of materials for mouthguards by manufacture, the dima® Print Mouth Guard material showed a higher elastic deformation than the conventional material and the dima® Print Ortho material showed greater resistance to compression than the conventional material. Based on the results obtained, it is suggested that additive manufacturing materials using SLA in the production of intraoral devices are efficient, offering a viable alternative to conventional materials

Abstract:

Os revestimentos refratários desempenham um papel fundamental nas operações metalúrgicas enfrentando condições extremas como altas temperaturas, estresse mecânico e corrosão por escória, resultando em perda de massa, espessura e consequentemente em sua vida útil. O estudo post mortem é essencial para compreender os mecanismos de corrosão e desenvolver estratégias de mitigação e solução para esses problemas. A identificação dos mecanismos predominantes permite a formulação de novos materiais refratários e tecnologias com o objetivo de melhorar o desempenho e aumentar a vida útil desses revestimentos em processos industriais que envolvem altas temperaturas. A abordagem proposta é uma revisão das metodologias utilizadas em estudos post mortem de revestimentos refratários de magnésia-cromo destacando os efeitos causados pela corrosão química por escória e os aspectos de infiltração ocorridos nos processos metalúrgicos.

Abstract:

Among the forms of existing steel corrosion, the most common are alveolar type and pitting. Coupons are metallic bodies of evidence used corrosion tests with multiple types and shapes, however, the most widely used in the corrosion monitoring are carbon steel which feature rectangular and disk formats. The current study aims to compare the characteristics of pitting corrosion in A213 T9 steel coupons through two microscopic methods, namely, optical and confocal. The coupons were tested in corrosion loop, with drinking water as fluid. The rules were adopted to such characterization were NACE SP0775 and ASTM G46-21. The conventional optical microscopy is a method quite used; however, there are some limitations. Confocal microscopy is a technique for characterization of digital high-resolution scanning laser beam, point to point (optical section) where images can be turned into three-dimensional images.

Abstract:

Corrosion inhibitors are essential for protecting metals against deterioration. The majority of commercial inhibitors, despite being widely used, suffer from limitations such as restricted efficacy and high toxicity. Plant-derived inhibitors, especially Moringa Oleifera oil, stand out as viable alternatives due to their compatibility with metal surfaces and low toxicity. Oleic acid, a monounsaturated fatty acid predominant in Moringa oil, grants the oil superior oxidative stability. Moreover, Moringa is easy to cultivate, with productivity up to 45 tons per hectare, and oil extraction can reach from 35 to 40% of the seed weight. This study focused on the potential of Moringa oil as a corrosion inhibitor in carbon steel. After exposure to a 3.5% saline solution, it was observed a reduction in mass loss of 0.02% compared to untreated samples.

Abstract:

Coupons specimens are widely used in the monitoring of corrosive process. There are different types and forms of corrosion coupons, which are the more used coupons in rectangular and disc formats. It is know that in the presence of neutral solution, the variation in chemical composition and microstructure of steels coupons carbon has little influence on the rate of uniform corrosion. However, the presence of defects and inclusions are leading to initiation and propagation of pitting corrosion in carbon steels factors. This study aims to evaluate the influence of coupon geometry in determining the rates of uniform and pitting corrosion, relating to the microstructure of materials. The characterization techniques have involved chemical and microscopy analysis. The coupons were tested in corrosion loop. To determine the corrosion rates NACE, ASTM and NBR standards were adopted. Coupons in rectangular and disk have comparable rate of uniform corrosion, however, evaluating the pitting corrosion changes are very significant.

Abstract:

Ferritic and austenitic stainless steels are susceptible to the phenomenon of sensitization after being exposed to high temperatures, which can promote intergranular corrosion. In this context, this work aimed to study the effects of welding on stainless steel joints welded by the MIG process, using an austenitic electrode addition wire (AISI 316LSi, %C ≤ 0.03% by mass), with a protective atmosphere containing high purity Argon. The formation of martensite islands was observed in the HAZ of AISI 430 (ferritic) steel, as well as significant grain growth in this region. At the fusion zone, AISI 430 and AISI 304 steels presented a duplex microstructure of austenite and ferrite. Furthermore, both showed significant precipitation of Cr carbides in the base metal, which may indicate the non-solubilization of these carbides in the samples of these steels in the delivery state. Potentiodynamic polarization tests were carried out on AISI 304 and AISI 430 steels in the delivery state, and the greater corrosion resistance of austenitic stainless steel was clear. Furthermore, heat treatments were carried out to evaluate the degree of sensitization of the steels. It was possible to observe that the two heat treated steels were susceptible to intergranular corrosion, and in a more pronounced way, the ferritic stainless steel. In this work, ASTM A262 and A763 standards were used.

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This work addresses the issue of corrosion in metallic materials, with a specific focus on AISI/SAE 1020 carbon steel. It highlights the importance of this type of steel in industry due to its mechanical properties, affordable cost, and ease of handling, but highlights its susceptibility to corrosion. It is explained that corrosion can be a chemical or electrochemical process, starting on the metal surface and resulting in its deterioration, which can lead to structural failures and significant economic impacts in various industrial sectors. To combat this problem, there is a growing search for natural corrosion inhibitors that are effective, accessible, low-cost, and environmentally safe. In this context, the mentioned study investigates the corrosion inhibitory potential of guava seeds on 1020 carbon steel. The results demonstrate that guava seed powder can inhibit the corrosion of 1020 carbon steel, with significant inhibition efficiency in media. water and NaCl. The effectiveness of green inhibitors is highlighted as a sustainable and economical alternative for preventing corrosion. Finally, it is suggested that the study be continued to better understand the mechanism of action of natural inhibitors and to consider other factors, such as exposure time and application conditions.

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Corrosion is broadly defined as the deterioration of materials, the result of spontaneous processes that occur between the material and the environment. The phenomenon of corrosion is a natural and inevitable challenge. Carbon steel is widely used due to its diverse applications, many of which are based on its excellent mechanical properties. This metal has high ductility (ability to deform), high tenacity, is machinable, weldable and has a low production cost, but has reduced corrosion resistance, making it necessary to use processes to delay the corrosive mechanism, such as the use of inhibitors. . Many of the inhibitors used are associated with high costs, environmental and human health risks, due to their toxic nature. Thus, the study of corrosion inhibitors from natural products is increasing, which are low cost and non-toxic. Natural products have stood out as promising sources of corrosion inhibitors, as they are formed through plant extracts or biodegradable materials, where many of these extracts contain compounds with antioxidant action. This present work aimed to investigate the inhibitory action of guava seeds on the corrosion of AISI/SAE 1020 carbon steel in a medium of HCl 1 mol L-1 at concentrations of 1 g L-¹ of seed powder. Mass loss tests were carried out using dried and crushed guava seeds (inhibitor) mixed in a solution containing a simulation of a corrosive environment (HCl hydrochloric acid). The specimens made of carbon steel were immersed in an HCl solution with and without the inhibitor for a period of 21 days at room temperature. The efficiency of guava seed was satisfactory as a green type inhibitor, reaching a maximum value of 59.11%.

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Stainless steel 316L (SS 316L) is widely used in chemical and petrochemical industries due to its favorable mechanical strength, weldability, and corrosion resistance. Its remarkable corrosion resistance is attributed to the formation of a passive chromium oxide layer. However, in highly corrosive environments, such as those containing chloride ions associated with acidic media, the corrosion resistance of this material may be compromised. The present study analyzed the influence of environment in the SS 316L corrosion resistance. Electrochemical tests were conducted to measure open circuit potential and potentiodynamic polarization in solutions of 3.5% NaCl and 3.5% HCl. The results showed that the acidic medium was the most corrosive, evidenced by the displacement of open circuit potential (OCP) and corrosion potential to less noble values, accompanied by a high corrosion current density. The electrochemical results were confirmed by the intense pitting corrosion on the SS 316L and the formation of corrosion products in the solution.

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With the increasing industrial need for materials with improved mechanical properties, it becomes important to study the behavior of modified alloys under different testing conditions, as understanding the behavior of these different materials in specific application environments is essential. This article aimed to analyze 9Cr steel modified with the addition of W and Ta when subjected to creep-fatigue. From the study, it was possible to observe both ductile and brittle characteristics in the samples, even with different exposure times to creep conditions. Using images produced by a scanning electron microscope, the fracture surface of the samples was analyzed to confirm the existence of secondary cracks and variations in the fracture mode. It was found that the material became more brittle with increased exposure time and load hold time, although it maintained a certain degree of ductility.

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There is a daily need to develop new materials, which generally must exhibit the most innovative properties that make them useful in the most varied fields of knowledge. In view of this, investigations into high entropy shape memory alloys (HESMAs) stand out. These materials combine unique properties of two classes of materials: high entropy alloys and shape memory materials. HESMAs have a complex crystalline structure and exceptional mechanical properties, combined with the ability to recover their original shape after thermal deformation. By combining these characteristics, high-entropy shape memory alloys demonstrate promising versatility in diverse applications, from biomedical devices to structural components in aerospace engineering. Their ability to maintain specific shapes even after large deformations and their resistance to high temperatures make them ideal candidates for applications in extreme environments. Continuous development in this field aims to explore its potential in new areas and improve its properties to meet the demands of various industries. This review aims to present the main topics inherent to these materials, highlighting scientific work carried out around the topic.

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This work investigates the influence of composition on the computational simulation of the highest formation temperature of the sigma phase in superduplex stainless steels during continuous cooling. The sigma phase is known to compromise the mechanical and corrosion resistance properties of these materials. With the aid of computer simulations in THERMOCALC® and DICTRA® softwares, it was possible to analyze the variation in the temperature at which the sigma phase begins to form as a function of the chemical composition, considering the variation of different elements. The results highlight that the presence or absence of certain elements, such as Cu, W, Mn, Si and N, can significantly change this temperature, revealing the complex interaction between the elements and the sigma phase formation process. Furthermore, the results can be compared with previous studies, demonstrating the importance of defining the temperature at which the sigma phase begins to form to use as input information in the DICTRA® software. Therefore, the methodology applied in this exploratory stage work is essential to understand and predict the formation of the sigma phase in superduplex steels.

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To guarantee the microstructural homogeneity of steels, which is only possible to obtain by inducing the chemical homogeneity of the material, the inherent segregations of the metal solidification process must be reduced or eliminated. The objective of this work was to study the influence of temperature and homogenization treatment time of a medium carbon steel by Dictra® simulation. The homogenization temperatures were 1000 to 1200°C, for a maximum time of 10 hours. As expected, the increase in temperature leads to a reduction in the time required for homogenization and, for a given temperature, the increase in time leads to a decrease in the chemical composition gradient. However, by simulation, the maximum homogenization time of 10 hours, even at the highest temperature (1200°C), is not sufficient for complete homogenization of the alloy, for the steel in question.

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The machining of aluminum consumes less energy and allows for high feedrates. However, the material has higher coefficient of thermal expansion and modulus of elasticity, making it difficult to obtain parts with small tolerances and having the tendency to warp. The 6060 alloy is widely used in frames and includes magnesium, silicon, iron, manganese, and copper in its composition, forming intermetallic compounds that improve the machinability of the material, superior to other alloys. The heat generated during aluminum machining is mostly dissipated by the workpiece, causing deformations, handling difficulties, and reduced tool life, which can be mitigated by using cutting fluids based on inactive sulfurized mineral oils. In this study, surface analyses were performed using SEM, XRD, tribological studies in pin-on-disk mode, and nanoindentation on anodized 6060-T6 aluminum profiles, comparing two groups of samples machined with and without cutting fluid. Additionally, an immersion test was conducted on the samples. The results showed that the samples machined with cutting fluid exhibited higher surface hardness and lower coefficient of friction. SEM, EDS, and XRD analyses did not reveal the formation of oxides or surface alterations in the samples that underwent immersion or machining with cutting fluid.

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Quantitative metallography represents a crucial role in materials science and industry by providing detailed information about microstructures, which are consequently related to the properties of materials. This article’s goal is to describe a practical method for using the open-source image processing program, ImageJ, in the field of quantitative metallography, in order to expand and optimize studies in this area with the vast resources of this versatile and free tool. Thus, with the developed methodology, it has become possible to calculate grain size, pore area, and the volumetric fraction of phases in a microstructure in a simple and quick way, using practical and automated methods supported by the use of plugins such as jPOR and the creation of detailed and didactic tutorials.

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Instituto Militar de Engenharia has been developing a new concept of metallic shielding, the shielding with polyundular format. The proposed geometric shape becomes a major challenge for traditional manufacturing processes, in which new modeling or machining steps are required. From the context that aims to evolve with this work, a study of the application of additive manufacturing in the manufacture of these polyundular plates was initiated, for which the mechanical properties of maraging steel plates 300 produced by additive manufacturing manufactured by selective laser melting were compared. and produced by conventional manufacture, varying the thermal treatments that both were submitted. The results obtained indicated positive factors both in the use of additive manufacturing as a possible resource for obtaining plates with good mechanical factors, as well as possibilities for optimizing the thermal treatments of maraging steel 300.

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IA armor new concept has been the object of study at the Instituto Militar de Engenharia, which consists of polywave metal sheets. The additive manufacturing technique has proven to be a good alternative in the manufacture of this sheets type. Therefore, this project proposes to investigate the ballistic behavior of prototypes made by additive manufacturing of polymeric feedstock to evaluate the behavior of different polywaves geometries in the optimization of armor for public security. Through the results obtained it was concluded that the polywave geometry showed better performance. Additionally, the lateral region exhibited higher values of absorbed energy compared to the peaks and valleys of the polywave geometry.

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In this work, the results of the characterization of PVA-based composite cationic membranes with different concentrations of graphene oxide and their performance when applied in a fuel cell prototype were presented. Membranes with three different concentrations of graphene oxide (GO) were prepared. The characterization of the membranes was performed using atomic force microscopy to verify the morphology of the membranes when hydrated. The thermal resistance of the membranes was evaluated by thermogravimetric analysis, and the ionic conductivity of the membranes was analyzed by complex impedance. In the fuel cell prototype test, the composite membrane showed an open circuit potential of 0.6 V and a power of 0.18 W, compared to the Nafion membrane with an open circuit potential of 0.8 V and a power of 0.12 W under the test conditions in the cell.

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Computational models based on density functional theory (DFT) are today considered valuable tools for the study of molecular electronic structure. Despite these notable features, it remains true that the exact density functional is unknown and approximations must be introduced. Current computational methods allow calculations of electronic and geometric structures relevant for studying diffusion. The central goal of modern electronic structure calculations is to find the ground state energy of electrons in molecules. The central goal of these calculations is to determine many basic properties of a molecule, such as bond lengths and angles, dissociation energies, and transition state barriers, for any configuration of the nuclei. This study aims to evaluate the accuracy of several density functionals, specifically TPSSTPSS, B3PW91, HSEH1PBE and PBE1PBE, evaluating the reliability of these functionals. The evaluation of these functionals will allow us to identify the most reliable approach to simulate the diffusion of boron in iron. In this way, selection is crucial for subsequent simulations and can provide valuable information about the diffusion process, ultimately aiding in the design and optimization of materials with desired properties.

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Cobalt possesses characteristics that make it highly suitable for the production of batteries, alloys and superalloys, catalysts, among others. The production of cobalt materials in their metallic form is particularly interesting for the automotive and aerospace industries, as cobalt is a metal with well-defined properties, resistant to corrosion and high temperatures. Additionally, cobalt is a limited and valuable resource, making it important to explore ways to maximize its utilization. Therefore, the electrowinning of cobalt was evaluated using different concentrations of manganese ions and sodium lauryl sulfate in cobalt sulfate solutions separately, in order to identify their effects on current efficiency responses, specific energy consumption, and the microhardness of the deposits. Sodium lauryl sulfate increased current efficiency and decreased energy consumption, while manganese ions had the opposite effect. Both additives reduced the microhardness of the deposits.

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The processing of ornamental rocks generates a large accumulation of waste resulting in high environmental impacts, as it is a non-biodegradable material. On the other hand, there is several research aimed at creating sustainable practices for the use of this waste. Therefore, this work aims to analyze the use of this material in the production of mortars, aiming to reduce its environmental impact. The mortars in this study were analyzed in their fresh state, using granite powder as a partial replacement for lime (CaO), in percentages of 10%, 20% and 30%, in addition to a reference trace without adding residue for comparison. For this, consistency index, density, viscosity and entrained air tests were carried out. In general, the gradual addition of granite powder affected the fluidity of the matrices, influencing their spreading. A 30% substitution showed an increase in scattering, suggesting physical and chemical interactions between the materials. The density initially decreased up to 10% of replacement, however, there was an increase for the other percentages, indicating better compaction. The replacement also reduced the air content and increased the viscosity of the mortar.

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The capacity to handle solid bulk in a port terminal is directly linked to the installed equipment, which is designed to move materials with specific characteristics, such as density, moisture, granulometric distribution, chemical composition, etc. Changes in the iron ore processing process can drastically alter its flow properties, transforming it into a new product and bringing the need for adaptation in both the design and the way the equipment operates. This work shows the adjustments made to a port terminal for handling iron ores with different origins and in their processing, making them less dense. Several laboratory tests were carried out to characterize the flow properties of the new ores with the aim of feeding virtual models of the equipment to size the handling capacity and operating model. The new defined model was tested and optimized through assisted operation on the port's main equipment, bringing significant results in reducing corrective maintenance hours related to chute clogging and corrective cleaning hours related to material leaks in the terminal boarding.

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The level control of one ore silo, feeded by bucket wheel reclaimers, with the aim of regulating the flow in the iron ore shipping process, in addition to being recent, is extremely challenging. Using material tracking techniques and mathematical modeling, it was possible to create a control loop that takes into account transport delays and process disturbances, allowing the creation of a dynamic and robust control strategy, using a single expert system (Lynx RTP), and enabling the creation of new feeding strategies for ship loaders and, consequently, increasing the harbor's productivity.

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The characterization of coils is the process in which it is necessary to evaluate the characteristics of coils that have been declassified, that is, are not allocated to a sales order, to align them with commercial technical standards that allow for their sale. These characteristics include dimensions, chemical composition, mechanical properties, quality, and applicability. Since each coil has individual characteristics, the evaluation process is also individual, resulting in a laborious and error-prone task that can lead to accidents for customers. Therefore, it is crucial to automate the characterization process, not only due to the speed of the process, which leads to greater stock turnover and increased sales potential, but also to mitigate risks. The automation was achieved by using real values from hot-rolled coils measured throughout their manufacturing process, comparing them with tables containing the values and tolerances for each applicable technical standard, based on the translation of business rules into the program algorithm. Over six months, the volume of material available for sales increased by 738%, and the volume of liabilities decreased by 84%, with a 45% reduction in declassified stock of this product at ArcelorMittal Brazil and a 67% increase in stock sales revenue, justifying the investment in this project.

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This study investigated the implementation of a customized water treatment to address challenges of spray nozzle clogging and corrosion in an industrial cooling system of the continuous casting process of a Brazilian steel mill. The adopted solution, using Performax DC5500 and Performax SR5600, resulted in a significant reduction in clogging and corrosion rates, ensuring a more efficient and stable operation over time.

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This article explores the fundamental role of the steel industry in greenhouse gas emissions and investigates the potential of replacing natural gas with hydrogen in the mixed gas used as fuel in the integrated steel plants, considering scenarios applied to a plant in Canada. An iterative optimization approach was implemented using Viridis Energy & Sustainability, a digital tool for assessing the cost-benefit of hydrogen integration. The study evaluates three scenarios with varying natural gas concentrations, highlighting the trade-offs between emission reductions and economic feasibility. Results indicate that hydrogen substitution effectively reduces CO2 emissions, but it concurrently raises fuel costs due to the existing price disparity between hydrogen and natural gas. However, it is expected that the CO2 emission tax will increase over time, making this substitution more advantageous. The study concludes that hydrogen substitution holds promise for decarbonizing the steel industry, despite increased fuel costs, alongside the validation of Viridis. However, there is a necessity for specialized burners to accommodate hydrogen's combustion characteristics and the importance of robust hydrogen infrastructure for a successful transition. Continued advancements are crucial to overcome the current economic barriers and ensure the long-term sustainability of the steel industry's decarbonization efforts.

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Given all the technical, environmental and economic advantages presented recently by epoxy matrix composites reinforced with natural fibers, considerable efforts has been made in researches aimed at mechanically characterizing them for subsequent use in industrial applications. This present study seeks to obtain some tensile mechanical properties that are essential for the continuity of structural analyzes that are necessary with regard to the utilization of multiphase epoxy matrix material reinforced with medium and high theoretical volume fractions of ramie woven fabric in wind turbine towers. After the experimental tests designed on six groups of specimens (40%, 50% and 60% of reinforcement volume intact and aged by ultraviolet rays and condensation) the degradation of properties measured for the simulated specimens was noticeable, which reveals the need for use of protective coating in view of an experimental design with this material. Finally, the elastic moduli and the tensile strength between the three volume fractions of intact samples were shown to be statistically distinct via inferential analysis and make up the set of mechanical properties of this composite that are essential to the subsequent structural analysis.

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The Drawer, the Danieli four-rolls sizing block, is a breakthrough technology to produce premium quality bar. From the first installation in 2017, indisputable facts and achievements have been reached, making this technology a cutting-edge solution for the SBQ market

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A new design solution for a system to supply water to in-line cooling boxes in high-speed wire rod mills has been developed. Variable-frequency pumps and a series of isolation valves significantly reduce the lag time needed to achieve setpoint temperatures, minimizing the transition length at the head end of each billet. This is important in achieving the desired metallurgical properties for small-diameter products at high speeds. Results of trials on a prototype system are presented to demonstrate the capabilities of the patent-pending design

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In recent years, it has been observed that the impurity levels in available iron ores have significantly increased, as has the growing demand for steels that meet increasingly stringent quality requirements, particularly regarding residual phosphorus (P) content. Steel production processes via primary oxygen refining present challenges concerning process optimization, aiming for operations with higher P inputs in the charge while meeting the demand for low phosphorus levels for casting. Despite being a widely studied process for primary refining furnaces, there is still a need for better understanding of the dephosphorization process in Energy Optimizing Furnaces (EOF), where the slag removal timing during heats represents a crucial step for phosphorus control at the end of the blow. This paper addresses the main metallurgical principles and discusses the application of various existing models and their applications and similarities with the primary refining process via EOF.

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This article emphasizes the importance of quality control in the steel industry, focusing on removing surface defects in steel plates caused by casting alarm events. Ternium Brazil successfully implemented directed scarfing to mitigate these defects, resulting in a significant reduction in plate rejection. The positive impact on material quality and the Quality Drop Indicator reflects the success of the company's continuous improvement process, enhancing its competitiveness and commitment to operational excellence and customer satisfaction.

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It is widely known that avoiding the excessive passage of slag from the converter to the ladle is of great importance, since BOF slag contains oxides that can be harmful to the process and the final quality of the product. One of the oxides to be avoided in ladle slag is P205, since phosphorus can revert to liquid steel, leading to deviations in chemical composition. At Ternium Brasil, slag retention is carried out using the slag stopper (combined with the AMEPA system) as the main retainer, and the slag ball is used as a secondary retainer alongside the slag stopper for producing low phosphorus steels. However, the gain in slag retention from combining the slag ball to the slag stopper was unknown. Therefore, the aim of this work was to quantify the reduction in the passage of slag carry-over from the BOF converter to the ladle during the BOF tapping by combining the slag stopper and slag ball retainers at Ternium Brasil. To this end, several improvements were implemented with the aim of increasing the efficiency of slag ball, which initially stood at 20% and by the end of the project showed 50%. Results also showed that sealing the taphole with both retainers resulted in a reduction of approximately 0,9 kg/ton of passing slag/ton of steel when compared to retention only with slag stopper, which leads to a reduction in P pick up of 8 ppm.

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The search for sustainable alternatives for the reuse of mining tailing has led AMG, in partnership with the Financiadora de Estudos e Projetos (FINEP), to conduct studies to identify routes for the disposal of aluminosilicate generated in the current production of spodumene concentrates, tantalum, and in the future production of lithium carbonate. Through analyses using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Fluorescence Spectrophotometry (XRF), and complementary X-ray Diffraction (XRD) analysis, the spodumene flotation tailing (tailing I) was directed towards the first phase of project development. The geopolymers and cementitious materials to be produced result from chemical reactions between the aluminosilicate tailing, metakaolin, and the alkaline activating solution sodium silicate and sodium hydroxide. Tests allowed determining the ideal proportion of components for the geopolymer activating solution. Different proportions of spodumene flotation tailing, namely 50%, 60%, 65%, and 70%, were used for producing test specimens. To quantitatively assess the performance of the materials generated, they were analyzed for their mechanical resistance, using the white sample with no tailing added as a comparison standard. It was identified that the sample composed of 50% tailing I would be ideal, and further tests were conducted accordingly. For tailing II, from the lithium carbonate production process, analyses with different compositions were carried out; however, they did not exhibit sufficient strength. The project has the collaboration of Escalab – UFMG lab and together with the AMG Brazil team, conducted proof of concept and bench-scale product development, and contributed to the structuring of the production space and industrial layout based on AMG's production needs. The project reaffirms AMG's commitment to sustainability.

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Petroleum coke (PC), a by-product of petroleum distillation, has gained significance in industrial applications due to its high carbon and low ash content. However, its effect on coke strength after reaction with CO2 (CSR) remains debated. This study investigates PC's influence on CSR in a Brazilian heat recovery cokemaking plant using stamped charge blend preparation. Historical data analysis of 102 blends classified by PC content revealed an optimal PC content range for CSR enhancement. Non-linear regression indicated an initial zone with little influence, followed by an improvement zone up to 25% PC content, then a decrease. Laboratory tests supported these findings, confirming an optimum point around 20% PC content. Results suggest a potential to optimize PC use for enhanced coke quality, offering opportunities for blast furnace coke rate reduction.

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The paper explores the transition from Metallic Blast Preheaters (MBPs) to Kalugin Top Fired Stoves (KTFS) in Mini Blast Furnaces (MBFs), assessing both feasibility and performance implications. It describes the features of Kalugin Stoves and compares them with conventional stoves. Drawing on case studies from Indian MBFs, the paper evaluates the economic and operational advantages of this technological transition, supported by performance data and relevant references. Through an analysis of heat balance, it calculates the efficiency of utilizing blast furnace gas heat for both the MBP and KTFS.

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In the year when the Minas-Rio operation completes 10 years, a bit more than a decade is completed of studies in partnership of this business unit from Anglo American with UFRJ towards development of a digital calibrated version of the comminution circuit. The work presents a brief history of the partnership, with lessons learned in the development of the circuit simulation, culminating in the use of the Integrated Extraction Simulator (IES), a cloud-based integrated multicomponent simulator. The work presents results from simulation case studies with the aim of identifying potential for increase in energy efficiency, as well as assessing the future impact of increase in proportion of supercompact itabirite in the Run-of-Mine ore.

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Good biocompatibility and corrosion resistance coupled with suitable mechanical properties make pure titanium (Ti) a widely used material in biomedical engineering and industry. High-purity Ti plates have lower mechanical strength than Ti alloys. Thus, heterostructured materials constitute an emerging and promising field to drive mechanical properties through economic routes. Partial recrystallization has been used to improve the ductility and strength of metallic materials. This work proposes to achieve a combination of high strength-ductility by incorporating the martensite phase precipitation αlpha' during partial recrystallization into commercially pure Ti (CP). After annealing for 30 min of a cold-rolled microstructure at 66%, the mechanical properties increased at temperatures of 600°C-700°C. Three hardening stages were identified during the tensile tests at room temperature. The plastic deformation of the Ti CP occurred without the formation of mechanical twinning.

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In recent years, the increase in Brazilian crude steel production has caused a shortage of iron ore and pellets, driving up their prices. This created the need to develop new sources of these inputs and study flexibility in production processes to deal with different materials. Pellets represent 65% of the matallic charge in Aperam's Blast Furnaces and 72% of it is used in Blast Furnace 2. Until 2021, only one type of pellet was used due to differences in chemical, physical and metallurgical qualities, limiting supply to a single supplier. The objective was to increase the flexibility of the Blast Furnace 2 load and eliminate dependence on this supplier and, in the results, there were no significant changes in the process variables, indicating that the use of a mix of pellets did not affect operational stability and productivity. However, there were notable benefits such as greater flexibility and negotiating power, loading options in case of pellet shortages, and budgetary flexibility.

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In this work, the effect of adding graphene oxide (GO) in the electrolytic bath on the morphology, structure, composition, and resistance to corrosion at high temperatures of Zn-Ni coatings obtained by electrodeposition was evaluated. For this, carbon steel samples were coated from baths containing different GO concentrations, and then subjected to heat treatment at 900°C. The GO addition effect in the electrodeposition and dissolution of the coating was evaluated by cyclic voltammetry. The coatings were characterized by scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. The oxidation resistance during heat treatment was also evaluated by thermogravimetric analysis. The results showed that with the increase of GO concentration in the bath, the coatings presented a uniform and compact morphology, and were resistant to oxidation, proving suitable for protecting the steel at high temperatures.

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This work discusses the implementation of asset virtualization in Vale S.A.'s maintenance strategy, highlighting the crucial role of digitization in optimizing operations and promoting sustainability. It introduces the concept of the Digital Thread as an essential integrated strategy for effective asset management, enabling continuous data flow throughout the asset lifecycle. The paper explores challenges in maintaining large-scale equipment and the need to comply with environmental and safety regulations. Technological solutions, including Teamcenter and Tecnomatix, are presented to overcome these challenges. Key findings indicate cost reduction, increased operational efficiency, and failure prevention through predictive maintenance. The conclusion emphasizes comprehensive asset management transformation, driving greater innovation and sustainability, while highlighting the importance of technological innovation and collaboration in addressing industry challenges.

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The Energy Optimizing Furnace (EOF) distinguishes itself through its innovative approach of preheating solid materials using energy from previous heating cycles. This method offers several benefits, including reduced chemical energy consumption, shorter tap-to-tap durations, and increased flexibility in utilizing various metallic charges such as hot metal, scrap, and pig iron. This study aimed to optimize oxygen bottom blowing to improve metal yield and reduce wear on tuyeres and refractory blocks by adjusting flow parameters and tuyeres design. Using a digital performance model, oxygen flow was adjusted based on historical data. Tests with smaller diameter tuyeres were conducted to assess the feasibility of wear reduction. A significant decrease in refractory-specific consumption was observed, indicating enhanced system performance. Comparative analysis revealed that adjusting the blowing regime contributed to wear reduction, resulting underscores the importance of oxygen blowing optimization for performance and extended refractory component lifespan.

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Decomposed mafic and chemical canga, referred to as clay waste, are friable lithologies that contain clay minerals, making it difficult to handle these ores due to their low flowability. This challenge has been observed at the Serra Sul mine, where the clay waste can reach up to 20% moisture, impacting the stability and leverage of the site's production indicators. Reductions in mass flow and operational stoppages due to obstructions in chutes, hoppers, grizzlies, and crushers, as well as avalanche risks, are some key points of concern for the flow of this waste. Bench-scale and industrial-scale tests have shown that the use of Super Absorbent Polymer (SAP), with dosages ranging from 300g/t to 500g/t, leads to significant improvements in operational performance, reducing operational stoppages and increasing the hourly throughput of the circuit by up to 50%.

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With the significant evolution of technology, where almost every type of device is connected to the network and various software applications are installed on a single asset, a new challenge arises for managing hundreds or even thousands of devices in a corporate environment. The need to ensure the proper functioning, security, and updates of these assets becomes crucial to prevent failures, vulnerabilities, and negative impacts on organizational processes. In order to reduce operational costs and mitigate cyber risks, this work aims to integrate data from software used for cybersecurity in the industrial automation sector of ArcelorMittal Aços Planos Brazil, with a focus on asset management. It was observed that the existing asset management practices in the company were not the most suitable, many manual and repetitive procedures were affecting efficiency. By providing a broader and more comprehensive view of automation assets through the proposed solution, identifying, and classifying risks, and supporting strategic and tactical decision-making to mitigate threats, this approach ultimately enhances cybersecurity in the company’s automation environment.

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In Brazil, according to the Superior Labor Court, a worker dies every 3 hours and 47 minutes due to work-related accidents. In light of this and the importance of each employee's safety, TECNORED's automation team, a company focused on sustainable initiatives for the steel industry, developed a lockout solution integrating Rockwell Automation softwares and hardwares. After five years of use, the system has proven to be safe, efficient, and auditable, meeting established expectations. However, to ensure its relevance and its effectiveness, implementing a process of continuous improvement is crucial.

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The Project consists of the installation of automatic reclosers in the 13.8kV Power Distribution networks in Germano – SAMARCO, providing remote maneuvers route supervision, causing a shorter time of operation and a higher level of safety in the interventions, minimizing the impacts on the operational process.

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The contact of water with the plate at temperatures exceeding 1300 ºC triggers its vaporization, initiating the corrosive process known as exfoliation within the chamber structures. In light of this, the objective of this research is to assess corrosion in the spray chamber caused by chlorides present in the water used for cooling. The use of sodium hypochlorite as a biocide is the primary source of chlorides in this system, as the application of biocides is essential for the chemical conditioning of water. To achieve this, immersion tests, polarization curve acquisition, optical microscopy assays to investigate sample surfaces, and industrial tests with specimens were conducted. Experiments simulating chemical conditioning under real operating conditions were performed to determine corrosion rates after the use of sodium bromide as a biocide. The results demonstrate an approximately 50% reduction in corrosion rate when chloride concentration was decreased in the operational environment, validating the findings obtained in immersion/emersion tests and electrochemical analyses. This scenario points towards a significant mitigation of corrosion effects, with positive implications for the economy and durability of metallic structures within the spray chamber..

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This study investigates the Charpy and Izod impact resistance of polyurethane matrix composites derived from castor oil, reinforced with Embira-Branca (Daphnopsis utilis) fiber using mass fractions of 50%, 60%, 70%, 80%, and 90% of Embira. The specific impact absorption energies and Charpy notch energies remained constant with increasing mass fractions of Embira. While the specific Izod impact resistance of the composites with 50%, 60%, and 90% reinforcement, due to no statistically significant differences in their means, was classified as group (a); similarly, the specific Izod impact resistance of the composites with 60%, 70%, and 80% reinforcement, also due to no statistically significant differences in their means, was classified as group (b), with the 60% reinforcement fraction common to both groups. However, the average specific Izod impact absorption energy of group (a) was found to be 40% higher than that of group (b). Additionally, group (a) exhibited an average specific notch absorption energy 27% higher than that of group (b), with fractions of 50% and 60% of Embira being common to both groups.

Abstract:

Extrusion is an important metal forming process. This paper presents a stress simulation study on a Platen, considering 3 scenarios: original design, current Platen and a Platen after machining. The original Platen presents high stresses, above the yield stress of the material, while the current platen and the machined platen present yield stress values below the limit for the material studied, thus the computer simulation study proved the need to modify the platen. to relieve tension

Abstract:

Currently, two rolling strategies are used to produce the S700 in the hot strip mill. The first one is to target precipitation hardening and the second one, to focus on strain hardening followed by accelerated cooling. In this paper, a detailed characterization was carried out using tensile and Charpy tests, as well as metallographic analysis by optical microscopy, SCAN, SCAN-EBSD, Automated Steel Cleanliness Tool (ASCAT) and TEM on hot-rolled coils produced using these two rolling strategies. For the strain hardening strategy, accelerated cooling was deployed minimizing the impact of precipitation on the HSM runout table. The results suggest advantages in the strategy of strain hardening followed by delayed accelerated cooling

Abstract:

This project aims to develop a comprehensive database that records lessons learned from previous experiences, with the goal of increasing accuracy in future treatments. By retaining and utilizing this accumulated knowledge, significant improvement in the quality of steel development is expected, promoting more efficient operations and better-informed decisions. The application of Artificial Intelligence (AI) in industrial steelmaking operations represents a promising approach in the pursuit of excellence in steel development quality. By integrating AI tools, such as machine learning systems and advanced data analysis, with Knowledge Management initiatives, organizations can not only capture and share knowledge efficiently but also use it strategically to enhance processes and products. In this project, we explore the application of the Copilot Studio tool to integrate industrial knowledge data stored in a database with an artificial intelligence chat. This integration ensures that users have quick and accurate access to necessary information, promoting operational excellence and continuous innovation.

Abstract:

One of the calcium addition objectives in steels is to modify inclusions aiming for continuous casting process stability and product improvement. Despite the treatment benefits, there are challenges regarding the alloy yield optimization, the alloy amount to be added and the repeatability in the heats. Alloy addition at the ladle bottom is recommended since the higher metallostatic pressure inhibits calcium vaporization. Calcium alloy is injected in a wire form, surrounded by a metallic sheet, which protects the core. Several parameters may influence the alloy release instant in liquid steel, such as injection speed, bath temperature and wire characteristics. In this work, the release depth of calcium alloys in liquid steel was calculated and tests were carried out with injection speed variation in experimental heats, comparing their effects on yield. A numerical procedure was used to estimate the release depth, study trends and parameter influences on calcium treatment. To validate the calculations, 91 industrial heats were monitored, in which four injection speeds were tested for two wire types: calcium silicide (CaSi) and pure calcium. The speed variation did not result in calcium yield changes. In this way, the use of higher speeds may promote shorter addition times and, consequently, productivity gains. Furthermore, there was good agreement between the numerical procedure calculations and industrial test results.

Abstract:

Calcined clay aggregates which exhibit heating temperatures above 600°C and demonstrate promising mechanical strength. Therefore, this study aims to utilize the technique of manufacturing artificial aggregates from a mixture of natural clay soil, sandy soil, and iron mining residue, known as red mud. The feasibility and characterization of the mixture used to produce calcined aggregate will include physical characterization tests of the soils and mineralogical analysis through X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The use of a clay mixture to produce aggregates through calcination has proven to be feasible, provided that the appropriate mineralogical analysis is conducted to utilize the higher pozzolanic activity of the present clay minerals and, therefore, achieve greater mechanical strength of the aggregate.

Abstract:

A coke battery is composed of a refractory body built on a concrete structure and tied by metallic structures and can be of the By-Product type (with recovery of by-products) or Heat Recovery (horizontal). The preservation of coke batteries is essential to guarantee the stability of the increased process in line with operational standardization at an appropriate pace, resulting in reduced useful life and reduction of their apparent age, since the cost of repair is high and implies loss of age coke and gas production, in addition to possible environmental impacts. This work demonstrates the main mandatory activities to reestablish the refractory and metallic integrity in a coke battery, through emergency repairs.

Abstract:

The hot stoves of a blast furnace are core to the overall furnace operation. The performance of the stoves has a direct impact on the hot blast temperature and therefore cost of metal production, and their failure or inability to operate can be extremely damaging to the process stability and economic performance of the furnace. While it is often possible to perform repairs to a hot stove independent of furnace shutdowns, the strategies available to do this are often expensive and disruptive to production. It is therefore valuable to extend the life of a hot stove so that major repairs can coincide with a furnace shutdown or other more convenient repair time. However, executing a fitness-for-service assessment to safely extend the life of a hot stove is not trivial. It requires an intense interdisciplinary approach and significant collaboration between the operating and engineering teams to ensure that the business objectives can be met through practical, effective, and minimal interventions. With the proper planning, specialist engineering, and collaboration between all stakeholders, the life of a hot stove can be managed to meet the operator’s needs.

Abstract:

Iron ore production has led the percentage of mineral production in Brazil over the years, and a large part of this production comes from the Quadrilátero Ferrífero region, located in the state of Minas Gerais. The high-grade iron ores extracted from this region are becoming exhausted, and the interest and need to develop process routes that can concentrate iron in low-grade ores, such as Dolomitic Itabirite, has gained interest. Associated with this need, and the growing trend of dry mineral concentration projects, which are easier to license, and reduce the associated impacts on the environment, it is necessary to develop dry mineral processing routes for carbonated gangue itabirites. In this sense, the objective of this study was to evaluate Triboelectrostatic Separation regarding its potential to benefit two Dolomitic Itabirite ore samples coming from the Quadrilátero Ferrífero region. The results obtained with the high-carbonate sample showed a removal of 86.4% of carbonates, a product with 35.3% Fe and 66.8% Fe recovery. A cleaner stage is required to get a product greater than 60% Fe. From a low-carbonate sample, a product with 60.4% Fe, 1.3% SiO2, with a silica removal of 96.2% and Fe recovery of 88.7% was obtained. The Triboelectrostatic separation showed to have potential application for Dolomitic Itabirite processing. Further TESTS must be performed in pilot scale triboelectrostatic separator and with a sample with higher liberation DEGREE of magnetite/hematite particles.

Abstract:

This study investigates the performance of grate bars used in the transportation of iron ore pellets during the firing process in pelletizing furnaces. Manufactured with high-temperature-resistant austenitic stainless steel, these bars are subjected to severe wear due to pellet abrasion and friction with gases containing abrasive particles. The steel's microstructure is characterized, scratch test are conducted to understand the behavior of a mono-event abrasive, using both a standard Rockwell C-type indenter and a modified indenter made of synthetic hematite to replicate the real contact between the iron ore pellet and the grate bar.

Abstract:

By focusing on an improvement opportunity in blast furnace process control, thought a significant reduction of time to obtain the silicon content result of hot metal, tests were conducted with a sensor able to measure the silicon content of hot metal online. For such, sampling and silicon content in hot metal were conducted for the same hot metal heat with the online sensor and with the chemical characterization by x-ray fluorescence (the current operational practice). A comparative analysis of the results based on 25 heats is presented and discussed in the present investigation. Temperature measurements were carried out and compared with the online hot metal silicon content sensor and TERMOTIP sensor of Vesuvius to verify the results convergence between both methods, once the online sensor for hot metal silicon content also has the differentiator of the temperature measurement. It was observed in both investigations a good results convergence of silicon and temperature of hot metal in the analyzed sample space, even though, there is an opportunity of adjustments for a better results convergence as discussed in the present investigation.

Abstract:

Non-stabilized stainless steel AISI 430 presents chromium carbides in its microstructure that are dispersed in the ferritic matrix of the steel. Depending on the thermal cycle used in the steel, these carbides preferentially precipitate in grain boundaries, generating a region pour in chromium next to them, what is a sensitization process. These sensitized regions are more susceptible to corrosive attacks. This way, chromium carbides dissolution in AISI 430 had been evaluated after heat treatments in different temperatures. Hot rolled and annealed samples had been heat treated in an electrical furnace and using a dilatometer. Temperatures varied from 750 to 1050°C, in 80s cycles and with fast cooling. From 950°C on, there is a decrease in the amount of carbides as the temperature of heat treatment increases. From 1000°C on, there is an increase in material hardness and martensite is present in the microstructure. Phase transformation during cooling occurs around 200°C.

Abstract:

In order to operate in a globalized and highly competitive economy, companies are increasingly relying on the implementation of an asset management system in their businesses. This paper discusses how world-class practices such as the Toyota Production System, the PDCA cycle and the ISO 55000 standard can contribute to the development of asset maintenance. One of the main requirements of the standard is the performance evaluation of the management system, which monitors and analyzes the achievement of results. The aim of this paper is to present the application of the VPS evaluation method, Vale's management system, in order to increase the maturity of maintenance processes at the Terminal Marítimo de Ponta da Madeira (TMPM). The main deviations associated with the low maturity of the processes were identified and based on this, meeting routines were structured, the frequency of application of the evaluations and an action plan was implemented. The main results of the new routine management were then discussed. As a result, the appropriate and structured use of policies, guidelines and assessments resulted in significant advances in the maturity of TMPM maintenance.

Abstract:

The study evaluated Robust Star Screen – Recimac in the processing of cohesive iron ore with high moisture. This equipment is widely used in the biomass, scrap and soil industries, but it has not yet been used in iron ore sieving. In four months of operation, the Robust Star Screen demonstrates greater productivity compared to the conventional vibrating sieve, with an average gain of 42%. The Robust Star Screen presents better performance with hydrated material, being able to process cohesive materials with moisture above 15%. It is currently still in the testing phase at Vale, requiring improvements in terms of maintenance to reduce premature wear of the stars and allow for quick replacement of axles.

Abstract:

With the advancement of technology, we have witnessed a growing integration of the Internet of Things (IoT) in the operations of the steel, materials, and mining industries. These industries, historically characterized by their robust and traditional nature, are now adopting connected devices and automated systems to optimize processes, improve efficiency, and drive innovation. This digital transformation is redefining the way these industries operate, enabling greater real-time monitoring, advanced data analysis, and a more agile response to market demands. However, this increasing reliance on cyber-physical systems brings significant challenges in terms of cybersecurity and operational resilience. The integration of IoT devices and process control systems (CPS) in steel operations, for example, exposes these critical infrastructures to new vectors of cyberattacks. According to Gartner, the first quarter of 2024 saw a significant increase in cyberattacks compared to the last quarter of 2023, highlighting the urgent need for robust and effective security measures. Cybersecurity in industrial operations has become a critical concern, especially in sectors like steel, where process disruptions can result in severe consequences for production and safety. A notable example is the attack on an Iranian steel plant by the hacking group Predatory Sparrow. This incident demonstrated the potential for cyberattacks to cause significant physical damage and operational disruption, underscoring the vulnerabilities within industrial systems. This paper explores the application of cyber vulnerability management solutions in a steel environment, detailing how their functionalities enhance asset visibility, threat detection, vulnerability management, and incident response. The analysis shows that the implementation of specific solutions leads to substantial improvements in the security and efficiency of industrial operations. The objective of this study is to investigate the effectiveness of a vulnerability management platform in operational technology (OT) and information technology (IT) operations, highlighting the importance of an integrated approach to cybersecurity in industrial environments. The increasing sophistication, scale, and impact of cyberattacks require an agile and informed response, and this work aims to contribute to the understanding and mitigation of these risks in the steel industry

Abstract:

The project aims to technologically update and ensure the operational continuity of Nº1 Continuous Galvanizing Line, installed at Presidente Vargas Steel Plant – CSN, in Volta Redonda - RJ. It began operating in 1973, continuously producing zinccoated steel coils for various applications and markets. The line operated for 50 years with its original analog controls, the Master Control GE, a technology from the late 1960s. Entirely carried out by an in-house team, the project to replace the Master Control and implement new automation systems for levels 1 and 2 began in 2020 in the Automation Technology Management, under the adapted PMBOK methodology. Level 1, based on the SIMATIC S7 platform and Siemens WinCC, was implemented in two phases to meet production planning. A significant challenge was overcome, considering that distinct technologies needed to integrate, with the startup occurring in May 2023. Level 2 came into operation later, in July 2023, integrating the line's operation with the production and management system. Thus, a new updated line was born, prepared for the new concepts of industry digitization, in addition to the human legacy of knowledge acquired by CSN engineering team.

Abstract:

The mining tailings filtration process has been increasingly widely used to reduce potential dangers and risks inherent to the maintenance and management of traditional tailings dams. The large alumina refineries have adopted the unitary filtration operation as a crucial step to adapt the humidity of the red mud generated in the process, greater recovery of caustic soda and subsequent disposal of the waste generated. The Veolia Solisep FLT9436E Dehumidifier acts in the filtration process, neutralizing any variables harmful to the process and challenges inherent to it (such as: different types of ores and their specificities, different types of filter fabrics, etc.) providing significant benefits at this stage, with effective humidity control (greater soda recovery), less need to change filter fabrics in addition to greater filtration efficiency

Abstract:

The present work aimed to develop a mathematical optimization model with the capacity to support strategic decision-making at VALE. It is an advanced analytical tool that harmonizes financial and environmental goals, assumes the multi-year distribution plan as a reference for volumes and qualities, and, respecting a broad set of constraints, selects investments in technologies and establishes operational and energy configuration profiles, as well as compensatory options, aiming for the systemic maximization of Vale's results and respecting decarbonization goals, reflecting a commitment to responsible profitability and corporate sustainability.

Abstract:

In recent years, there has been a significant increase in the development of new materials that combine good mechanical performance and biodegradability. In this context, the production of polymer matrix composites reinforced with natural fibers from the Amazon is emerging as a promising alternative. The vast diversity of species in the Amazon region offers a wide source of natural fibers that can be used to reinforce composites. Munguba fiber can be extracted from the munguba plant, which has shown potential for use as a reinforcing agent in polymeric matrices. The aim of this work is to study the microstructural characteristics of munguba fiber, as well as to evaluate the mechanical properties obtained in tensile strength of composites with added fibers in an epoxy matrix. The composites were produced incorporating 10, 20, 30 and 40 %vol. The fiber characterizations indicated density values, crystallinity index, thermal stability and functional groups characteristic of lignocellulosic fibers. In addition, morphological analysis by SEM revealed that the fiber has fine bundles of fibrils and a rough surface throughout its length. The tensile mechanical characterization of the composites showed that the strength, modulus and deformation values are comparable to those of other lignocellulosic fibres and that these fibres have the potential to be used as reinforcements in polymer composites.

Abstract:

Experiments were conducted to assess the effect of a higher hardness grinding wheel and different grinding machine parameters on the enhancement of surface roughness (Ra) in a HSS roughing working rolls. The results showed that Ra increased when the working rolls were ground with a higher hardness wheel, the number of grinding passes were reduced and the wheel in-feed rate machining parameters were increased. The mechanism of the improvement of the roughness surface is due to the deeper cutting. Furthermore, it was shown that the type of hardness abrasive grain had an influence on surface roughness. Finally, the performance of the harder grinding wheel was evaluated in comparison with the softer one.

Abstract:

This paper describes the successful startup of the world’s first twin-stand HYPER UC-Mill dedicated to produce high-permeability non-grain oriented (NGO) electrical steel and advanced high-strength steels (AHSS). The reversing mill features a new generation of a small diameter 6-high technology with driven work rolls and a high-torque MH-spindles. For cold rolling of high-grade electrical steel, the mill is additionally equipped with an induction strip heating system in combination with Minimum Quantity Lubrication MQL and an innovative strip temperature prediction and guidance system. Operational highlights will be presented in the paper.

Abstract:

Highest productivity and cost-optimized production are the key components for integrated BOF steelmaking to be competitive and profitable in the long run. For this reason, steelplants, - especially in the Americas and in Europe, focus on revamps, upgrades and modernization to ensure highest productivity, availability with minimum maintenance effort. This paper is presenting an overview of some of the current revamp projects, latest technology features and an outlook toward a greener BOF operation future. Examples for successful converter revamps will be shown based on the ongoing projects at Ternium 340t BOF and Arcelor Mittal Monlevade 135t BOF. Latest technology features for process improvements will include, the Vaicon Link converter suspension system, the Vaicon Sublance 2.0 for highest accuracy, shorter process time and the Vaicon slag stopper for contactless and fully automatic slag retention, as well as a new relining machine which makes BOF relining process much faster and safer. In the last chapter, an outlook will be provided which role the BOF converter will play in future green steel making process such as direct reduction and smelter and solution to reduced CO2 emission with increased scrap rate.

Abstract:

The planning process of continuous casting has a significant influence on productivity, yield, and production costs. For sequencing materials with different widths, it is necessary to produce slabs with width changes, or with taper, to transition from the current width to the required width for the subsequent item without the need to interrupt the production sequence. To maximize productivity, yield, and reduce production costs at the ArcelorMittal Pecém, a simulator was developed to promote the production of different widths simultaneously in each of the strands of continuous casting of slabs, where a 49% reduction in the generation of slabs with width changes was achieved.

Abstract:

Inert gas injection is performed to improve the mixing phenomenon, with gas being introduced into the reactor mainly through porous plugs/ tuyeres installed at the bottom of the ladle or through a lance submerged vertically into the metal from the top. Some studies have addressed steel desulfurization in a ladle furnace; however, gaps remain regarding plume behavior and metal-slag interaction. Using a physical model, this study compared a submerged lance and bottom blowing, evaluating the effect of gas flow rate on the velocity profile inside the ladle, mixing time in the reactor, dye dispersion, and the slag eye opening at the reactor surface. In the upper region of the ladle, higher velocity values were observed near its wall and close to the submerged lance, with higher velocity values also noted for the lance in the more off-center position. The longest mixing time occurs with the lance at a lower immersion depth, but the difference decreases at higher gas flow rates. Mixing time decreases and energy input increases with higher flow rates in all configurations. Greater decentralization and higher gas flow rates promote shorter mixing times and greater dispersion within the ladle. In the most decentralized position (P1), an irregular slag eye opening was observed, while in position P2 (closer to ladle center), the opening occurred in an oval shape around the submerged lance. For high flow rates, emulsification could be observed due to the high agitation of the system.

Abstract:

The iron ore production in the region of the Iron Quadrangle in Minas Gerais State has increased from 40 Mty to more than 280 Mty from the 1970s to the actual decade. The high production of iron products represents the main economical item of revenue in the State of Minas Gerais in Brazil. On the other way, the high and annually increasing tailings volume from the low-grade and complex itabirites mining and beneficiation stages represent environmental problems and further high costs with dams disposal. Reverse flotation of quartz is the main concentration process on the beneficiation plants of the Iron Quadrangle, with SiO2 content on the froth tailings close to 90%, partially destinated as sand for the civil construction industry. The addition of a high-intensity magnetic separation stage to remove part of the Fe-bearing minerals lost by entrainment and true flotation to the froth tailings can increase the SiO2 grade up to 96%, producing premium quartz for low-quality glass and other similar applications. A final concentration stage by flotation using specific collectors was evaluated in this paper aiming at the production of high-purity quartz (>99% SiO2) for alloy or solar panels or the semiconductor industry. Cationic collectors for quartz and alternative anionic collectors for the Fe-bearing minerals showed great potential to remove part of these minerals lost by entrainment, true flotation, and entrapment on the former concentration stages, enabling a premium quartz product with >99% SiO2, even with the presence of associated particles of quartz and hematite.

Abstract:

Coking plants investments require analyses of how resources behave in meeting production schedules. To conduct these analyses, a computational model was developed to represent the operational details of each battery and identify bottlenecks throughout production scenarios. By integrating constraint analysis into the operational index, the simulation aims to identify and mitigate any limiting factors that may affect coke battery operation. This approach allows the company to evaluate hypothetical scenarios, test different operational strategies, and anticipate potential bottlenecks or weaknesses in the process.

Abstract:

Dry blast furnace gas cleaning technology offers great economic advantages when compared to traditional wet gas cleaning owing to its improved energy efficiency, lower cost, reduced plot space, and practically eliminated water consumption. Given the improved operational economics and – in some areas – the physical or economic scarcity of water, steel producers are shifting towards the application of dry blast furnace gas cleaning systems, in which the wet scrubber is replaced with a dry secondary gas treatment stage. The Danieli Corus solution is based upon proven technology that has been applied numerous times for cleaning aluminum smelter gases and anode baking fumes. The system consists of a gas conditioning tower, reagent injection system and (pressurized) filter modules with low pressure pulse cleaning. Currently, Danieli Corus is implementing this technology for three greenfield blast furnaces in India. This article presents the advantages of the proven technology as well as some improvements that will be applied during the ongoing projects. These improvements include steam reheat of (cold) blast furnace gas, single phase water injection in the conditioning tower and two stage countercurrent absorbent injection.

Abstract:

The Ipueira Mine, operated by Ferbasa, is an important center for chromite ore production, utilizing physical concentration technologies such as jigging and Sensor-Based Sorting (SBS). This article compares the effectiveness of these methods in concentrating chromite within the -19+9mm size range. Currently, Ferbasa uses the traditional jig separation process for this size fraction, which relies on the density difference of minerals. The SBS technology is employed for coarser fractions and uses sensors to detect physical properties. Pneumatic jigging at the Ipueira Mine uses a BATAC jig to separate minerals, facing challenges with water supply. In contrast, SBS technology promotes dry processing, reducing the process's dependency on water. Tests conducted with XRT and Laser 3D sensors showed superior results compared to the jig in terms of metallurgical recovery and Cr₂O₃ grades. It was possible to achieve Cr₂O₃ grades that elevate the product to metallurgical quality, demonstrating greater efficiency and sustainability. The implementation of SBS in the -19+9mm fraction could represent a significant advancement for Ferbasa, improving product quality in this fraction and offering substantial sustainability advantages, especially in water-scarce regions.

Abstract:

The OCTG steel pipes classified as API 5CT, specifically the grade K55, are specified for casing pipes in oil and gas exploration wells. The steels used as raw material for manufacturing this type of product are of high mechanical strength and low alloy. Generally, they are quenched and tempered, therefore possessing a microstructure mainly consisting of tempered martensite. However, some studies point to the possibility of using biphasic microstructures composed of ferrite and bainite, aiming to improve the mechanical strength-toughness relationship of this steel type. In this context, considering the feasibility of producing a biphasic pipe through austempering heat treatment after intercritical autenitizing, this work investigated, through computational simulations and dilatometric tests, the effects of intercritical autenitizing on the isothermal bainitic transformation of an OCTG steel, with potential application in the oil and gas industry. It was concluded that, for the studied steel, it is possible to obtain a promising ferrite-bainite biphasic microstructure through adequate planning of intercritical autenitizing and austempering conditions. It was shown that decreasing the austempering temperature results in significant microstructural refinement of bainite, leading to a considerable hardness increase. Intercritical autenitizing condition at 750°C associated with bainitic transformation temperatures of 400°C and 350°C proved to be the most promising for the desired application.

Abstract:

Quality is one of most important indicator for Aperam. However, due to the challenges in each process, keep quality control always represent a challenge. In Aperam Timóteo Blast Furnances, hot metal quality means silicon e and temperature. Knowing that quality affects our process, we commited to increase the hot metal qualit using lean metodology. The silicon and temperature stability of hot metal brings benefits to the the blast funace and meltshop processes. Guided by the limits of hot metal specification and kwowing the silicon content has a positive and linear correlation with temperature, we know that would be necesary reduce the thermal variations to increase our quality. According to our methodology, we defined that the goal would be increase blast furnance 1 compliance from 78,20% to 81,08% and blast furnace 2 from 74,96% to 81,68%. The proposed targets were exceeded in both blast furnace with results equal to 92,80% in blat furnace 1 and 84,56% in blast furnace 2, breaking historial records. The increased silicon on target reduce its avarege from 0,657% to 0,601% that reduce limes in meltshop.

Abstract:

Microstructural banding is often correlated with observed drops in the mechanical strength and toughness of steels. This work presents a study of microstructural banding in quenched and tempered SAE 4140 steel, in which the influence of the cooling rate on the banding intensity and mechanical properties was evaluated. In the study, experimental quenching and tempering heat treatments were carried out on billets, for subsequent machining of mechanical tests and metallographic analysis specimens, varying only the quenching medium, where water, oil and air were used. In addition, dilatometry tests were carried out, simulating the austenitization process followed by quenching at different cooling rates, for subsequent banding evaluation. The results showed a correlation between the cooling rate and banding where it was observed that as higher the rate is, the lower the banding intensity and the higher the mechanical strength and toughness values of the steel. Finally, it was also possible to observe, using DIC and dark field (HRX) microscopy techniques, the existence of a difference in relief between the different bands present in the microstructure.

Abstract:

This study addresses the implementation of safety requirements in electrical and instrumentation installations in environments containing explosive atmospheres in the mining industry. The methodology involved inspections and studies in classified areas, aiming to identify gaps and demonstrate the reduction of non-conformities with adherence to standards and professional training. International standards were used, highlighting the importance of certifying equipment and personal skills to ensure compliance and safety. The results highlight the need for adequate management, including change management, and the importance of certifying service companies and personal skills to mitigate the risks of explosions in industrial facilities. It is concluded that regulatory compliance and process safety in the mining industry require not only equipment certification, but also certification of the skills of the professionals involved

Abstract:

Screening is a crucial stage in mineral processing, responsible for classifying particles by size and widely used in crushing circuits. In environments with natural moisture processing, such as Serra Sul, screening efficiency is fundamental to the overall performance of the plant. Variables such as screen rotation, acceleration, and vibration frequency are critical in the technical management by the process team, which aims to optimize these parameters to achieve maximum efficiency, especially under challenging conditions imposed by more hydrated ore lithologies. However, these conditions also result in increased wear of mechanical components, such as bearings. Given this scenario of variable feed lithology and high component wear, this article presents the application of a rule-based controller to reduce screen rotation in situations of low screening demand or absence of feed. This approach is expected to extend the equipment's lifespan without compromising process efficiency.

Abstract:

The rolling mill has a complex scheduling process, many logistic restrictions must be considered (has the slab to be rolled already been cast?) as well as operational constraints from the process itself (especially related to the coffin made). All this while attempting to produce the plates on the correct due date of the final client. In this sense, a digital twin system is developed to consider the available demands as inputs in order to inform the best configuration for the next coffins, attempting to minimize delays while meeting all the restrictions of the process.

Abstract:

With the expansion of the industrial plant and the increase in the mix of products and thicknesses, the samples collected from the production lines are heavier and difficult to handle manually. Considering this as an operational risk, we combine it with the opportunity to automate the sample entry process in the Laboratory with a robotic cell that has the functions of identifying, cutting to standard size, laser marking, cutting the necessary specimens and storing the sample. With this, we reduced team interaction to approximately zero in these initial operations of receiving and preparing samples and specimens, practically eliminating operational risk

Abstract:

This paper proposes the repurposing of decommissioned semi-submersible platforms for renewable energy generation by integrating solar panels and wind turbines. This approach aims to transform these structures into offshore sustainable power plants, providing advanced logistical support for naval operations and contributing to the reduction of the environmental footprint. The study includes detailed calculations of energy generation capacity and discusses the strategic and logistical impact of this implementation, both for military operations and for supplying coastal cities. The innovative use of semi-submersible platforms leverages existing infrastructure to promote clean energy generation, aligning with global trends towards sustainability and energy efficiency.

Abstract:

The use of the WCM methodology, through its technical pillar Energy/Environmental, can significantly contribute to reducing losses and consequently transformation costs linked to the use of energy in the steel industry. Implementation requires discipline, rigor and audits that consolidate each step applied until the 7 available steps are completely used. Knowing the strengths and weaknesses within the organization and working with methods, opens ways for the teams' multidisciplinary technical knowledge to be applied during the identification of each phenomenon that causes loss and, with the mapping of actions in a structured way in the methodology, allows the adequate use of resources, resulting in lower costs and greater competitiveness.

Abstract:

This study investigated the effect of adding carbon black (CB) to epoxy matrix composites reinforced with sisal fiber fabric (SF) on their ballistic performance. The components were weighed and mixed in optimal proportions, with 30% vol. SF and 5% vol. CB. After drying the fabrics, the mixtures were manually prepared and molded via hydraulic compression. The composites were morphologically characterized using scanning electron microscopy (SEM). Ballistic tests were conducted using an air rifle with a lead projectile, with chronographs to measure the absorbed energy and residual velocity. The results indicated a slight reduction of 2.4% in absorbed energy and 1.4% in the ballistic limit velocity of the doped composites compared to the non-doped ones. However, the absorbed energy values for the doped composites were statistically equivalent to the non-doped ones. It is concluded that the addition of CB results in a slight decrease in ballistic performance, but within the expected standard deviation. These findings highlight the viability of CB as a reinforcement alternative in epoxy matrix composites reinforced by SF, maintaining their eco-efficiency and mechanical strength.

Abstract:

The use of ion milling cross-sectional polishing (CSP) in defect characterization a great breakthrough in conventional metallographic sample preparation methods. The presented case study aimed to characterize a blister-type defect commonly found in phosphatized and painted parts using ion polishing, combined with electron microscopy, and evaluated its efficiency in this type of occurrence. The defect was associated with the presence of "debris" containing iron and phosphate particles that adhered to the surface, remaining during the electrophoretic painting and application of finishing paints processes. Ion polishing proved high efficiency compared to conventional metallographic preparation as it managed to maintain its integrity throughout all stages

Abstract:

Effective inventory management and fully automated handling play a crucial role in maximizing plant performance and equipment reliability. Predictable material flow and optimized logistics—from stock yards to final product bays—yield significant benefits. These include increased safety (with no personnel on the shop floor), enhanced slab yard capacity, improved system efficiency, and 100% digitalization. Ternium, part of the Techint Group, has partnered with Danieli to implement an Inventory Management System and fully automatic handling facilities for their new Hot Strip Mill in Pesqueria, Mexico. The mission is to optimize incoming slab flow using artificial intelligence within the Slab Yard Management System (DYMS), coordinating a comprehensive handling system to process 4.1 Mtpy of slabs.

Abstract:

Driven by increasing sanctions on CO2 emissions and the incentives outlined in the American Inflation Reduction Act, steelmakers and investors are seeking ways to produce steel with the lowest possible environmental impact, at a lower cost and with minimal investment. However, despite its emissions, steel is also essential for modern life. It's in cars and buildings, kitchen utensils, etc. Nearly two billion tons are produced annually worldwide, emitting nearly twice that volume in CO2. A significant portion of this CO2 is generated in BOF steelmaking, during both primary refining and, to a lesser extent, secondary refining. This study demonstrates the results of simulations using the Thermo Balance LD® primary refining simulation software (which operates during the steel blowing and casting stage) to calculate carbon emissions based on different alloy designs. This simulation involves altering carbon content by substituting manganese with microalloying elements in six different scenarios. Boundary conditions for the simulation were inferred from classic raw material data, varying the composition of the base steel, which is the product of primary refining. This is an innovative approach to how to associate alloy design with GHG emissions which can be used by steelmakers for the design and production of more environmentally friendly alloys.

Abstract:

The Heat Transfer during the Continuous Casting is a very important factor for the quality and process in general. Just below the mold, after the Primary Cooling, the next stage of heat transfer has a notable role in preventing the occurrence of surface defects and productivity through the control of flow rate from the spray cooling systems. However, during the process the spray nozzles can be clogged reducing the flow rate and, consequently, the efficiency of the process by reducing the casting speed. In order to avoid that, the present work evaluated the influence of the nozzle spray shape in the flow rate for a constant work pressure. The results showed an increase of 60% in the total flow rate capacity without negative impacts on the process or the integrity of the machine. As a consequence of the improvement in the flow rate there was a reduction of 90% in the loss of productivity due to low flow of the spray system. Besides that, the average cost per month to change the mold for reasons of low flow decreased 58%.

Abstract:

Tapping steel from converter to the ladle causes Strong agitation of the metal. For many years, this agitation has been used in different ways to make steelmaking faster and more efficient and to make possible the production of well deoxidized, clean steel. In the present work, a EERZ (Effective Equilibrium Reaction Zone) coupled to a computational thermodynamics software is used to evaluate options related to the additions to the heat during tapping when producing LCAK with high formability. The effect of different amounts of deoxidizers and of different amount of slag formers on the deoxidation and on the formation of a slag adequate for the further processing of the steel. For this purpose, kinetic data from previous work is used, together with an adequate computational thermodynamic database are used to simulate the changes happening to metal and slag during tapping, and until the heat reaches the next processing step. These data will be used to guide an experimental program aimed at improving the tapping practice with the objective of optimizing efficiency and minimizing the number of heats that deviate from the desired quality requirements of this product.

Abstract:

Studies on the use of iron ore beneficiation tailings, especially in unpaved roads, are becoming increasingly necessary due to environmental concerns and the search for economical alternatives for mining waste. This work, developed as part of Research, Development, and Innovation collaboration between Vale and the Federal University of Itajubá (UNIFEI) - Itabira campus, focused on the geotechnical analysis of a chemically stabilized lateritic soil with 4% Portland cement. Iron ore sand (IOS) was added as a byproduct of tailings, aiming for application in rural unpaved roads. The results showed a significant increase in California Bearing Ratio (CBR) values and unconfined compressive strength in the soil-cement mixtures with IOS addition.

Abstract:

The study under development deals with the application of 1.5% Colloidal Silica 30% in the mineral coal mixture. The main objective is to evaluate the performance of this mixture with silica in order to increase the strength of the coke produced. This approach also aims to achieve significant environmental gains, including the reduction of particulate emissions during the coking process and the densification of the charge used. This research seeks to promote more sustainable and efficient solutions in industrial production, standing out for its potential to improve both the performance of materials and the mitigation of environmental impacts.

Abstract:

In recent years, the field of computational fluid dynamics (CFD) has witnessed significant advancements, particularly in its applications for simulating and analyzing industrial flows. Among these applications, the study of cyclone separators stands out for its crucial role in the steel industry, where such equipment plays a vital role in environmental pollution control and cost reduction. While previous research has extensively examined the impact of vortex finder dimensions on tangential cyclones, the same level of investigation for axial cyclones remains less developed. Moreover, prior to this study, there was a lack of understanding regarding the erosion fields generated by the swirling separated material downstream from the equipment under scrutiny. To address these knowledge gaps, this study employs a two-stage CFD approach, aiming to not only fill these voids but also propose geometry alterations to enhance cyclone operation.

Abstract:

Biosurfactants is a microbial surfactant and are considered potential substitutes of synthetic chemicals from petrochemical origin. The main advantages of biosurfactants over their chemical counterparts are their lower toxicity, better environmental compatibility, biodegradability, and effectiveness in a wide range of temperatures and pH. In addition, it also has higher surface-activity. One important class of biosurfactants, which has been investigated is the rhamnose containing microbial surfactants, also called rhamnolipid, a glycolipid-type. It’s produced by Pseudomonas aeruginosa strains. Due to their features as well as structural similarities, rhamnolipids seems to be well suited to apply in the mineral processing industry as a substitute case for conventional chemical frothers. In this work two Evonik’s biosurfactants, AROSURF® SR 1975 and REWOFERM® SL 446 were investigated as frother, comparing with MIBCOL, in Zn flotation tests with a Nexa’s ore sample. Results showed that both Evonik's biodegradable frothers were able to improve the tests results, increasing %Zn in the concentrate and also recovery under certain circumstances. In addition, tests with reduced dosage in 20% of Evonik’s frothers showed promising in terms of flotation improvement, reduced consumption and even more sustainable.

Abstract:

The control of austenite formation in steels is crucial in various industrial processes, such as heat treatments, for example. The initial austenitic grains influence the microstructure and mechanical properties post-cooling. However, metallographic methods to reveal them are complex and often challenging to apply depending on the steel and the heat treatment it has undergone. This study sought to examine how the austenitizing temperature affects the microstructure of quenched TRIP 780 steel, as well as to evaluate whether the size of the austenitic grain influences the effectiveness of two contrast methods: chemical etching with picric acid and subcritical oxidation. It was concluded that austenitic grain growth affects the effectiveness of both methods. Chemical etching showed better performance at lower temperatures. In contrast, subcritical oxidation proved efficient under all evaluated conditions, successfully revealing the boundaries of austenitic grains. These results emphasize the importance of considering the austenitizing temperature and the choice of contrast method in the analysis of prior austenitic grains.

Abstract:

The liquidus temperature is one of the most important physical parameters in relation to the crystalline behavior of materials and in a blast furnace the liquidus temperature of the slag is considered one of the most important parameters with an appropriate range for stable operation in a blast furnace. Therefore, liquidus temperature is an important parameter in steel slags. The SciGlass database was used to provide steel slag data with the SiO2-CaO-Al2O3-MgO-FeO-Na2O-K2O-Li2O-B2O3-based slags and liquidus temperature system. The chemical composition data were converted into the degree of depolymerization parameters and subsequently related to each liquidus temperature. The modeling was carried out using neural networks by varying width and depth using a linear combination between different central moments as a reference of efficiency. The best neural network had a width of 19 and a depth of 10 (19-10). Sensitivity analysis was performed demonstrating consistency with the literature and statistical evaluations were performed to demonstrate the efficiency of the neural network 19-10 which demonstrated better evaluations in relation to different literature equations.

Abstract:

High chromium white cast irons are used in operations that require high wear resistance. This property is achieved by a microstructure comprising a network of eutectic carbides of the M7C3 (Cr7C3) type, combined with the possibility of heat treatment by quenching and tempering. This work analysis the heat treatment parameters on the response to quenching and tempering. For this purpose, phase equilibrium analysis was used using Thermocalc ®, hardening capacity was determined using Rockwell “C” measurements and phases were identified and quantified using X-ray diffraction and a ferritoscope. The results showed that the maximum matrix hardening is reached after austenitization at 950ºC, as consequence of the hardening capacity of martensite by the carbon content dissolved in the matrix and the lowest retained austenite fraction. During tempering, the secondary hardening peak is close to 500ºC. This set of results allowed the specification of the best heat treatment cycle for specific applications.

Abstract:

This article presents the methodology for defining technical references for the main performance indicators of Vale's processing plants in Minas Gerais. Using the Gap to Potential method, which differentiates between potential and actual available time, it is possible to identify performance gaps and opportunities for improvement. The analysis considered compressible and incompressible plant stops to prioritize the most significant causes of corrective stops, with examples of calculating physical availability and physical use. The concepts of technical reference and technical limit were defined, where the technical reference represents the best possible performance, and the technical limit includes operational restrictions. The methodology was applied to 5 production complexes, covering 19 plants, resulting in the definition of 84 technical references, which aim to guide the performance of each plant according to its shutdown notes. The application of this approach allows optimizing operations, direct improvement actions and make strategic decisions, promoting gains in productivity and efficiency in Vale's mining operations.

Abstract:

The mining sector is essential to the economy, driving technological and scientific progress, although it has negative environmental impacts due to the waste generated. This study proposes a possible recycling route for mining waste, focusing on the recovery of metals after comparative leaching with technical standards, with the aim of classifying the slag resulting from the reduction of Iron/Nickel (FeNi) and achieving the recovery of metallic waste, contributing to the sustainable disposal of mining waste. The sample was comminuted to a particle size of 0.3mm. A 1N NaOH solution was used as a leaching agent for 100g of the material. A Wagner shaker (18h, 30 rpm) and a vacuum filtration system were used for collection after the test. The dry retained materials, filtered and washed solutions were analyzed by XRD, XRF and ICP, revealing the presence of Forsterite, a mineral of magnesium and iron silicates, and elemental contents of Si, Mg, Fe and Ni of 19%, 18%, 15% and 0.14% respectively. With regard to the total chromium parameter, a value above 5mg/L established by the NBR 10004 standard was found. The levels of Al, Fe and Mn were also above the permitted standard