Assis International Symposium (9th Intl. Symp. on Advanced Sustainable Iron & Steel Making)

The growing world population, climate change, and geopolitical disruptions are major and global challenges of today. Consequently, governments and the private sector increasingly work towards responsible and sustainable development strategies to address climate change. These initiatives commonly recognize the importance of metals in the green transition, industry decarbonization, resource conservation. 

Steel is the most abundant construction material that plays a crucial role in the energy transition, infrastructure, mobility, and living standards in all regions. However, the annual cost of corrosion, estimated at US $2.2 trillion by the World Bank, is over 3% of the world’s GDP. Via galvanizing, zinc provides the most cost-effective protection for steel, decreasing overall lifetime maintenance costs and resource needs (raw material and energy) by multiplying the durability of steel constructions.  As a result, steel and zinc are closely interwoven at product level and in their recycling loops. When galvanized steel is recycled, both materials become available via mature recycling routes.

Innovations in galvanized steel production and use require flexibility and innovations. This relates to products as well as to production and recycling: Through joint projects such as the International Zinc Association’s Galvanized Autobody Partnership, both industries ensure that galvanizing technology advances hand in hand with innovations in steel production. Similarly, the durability of galvanized rebar used in concrete reinforcement provides increased safety for transportation and construction in corrosive environments (e.g., roadway deicing, offshore/coastal windfarms). The steel and the zinc sector both have developed decarbonization roadmaps. Impactful changes are under way that will result in technological changes in steel production. The zinc industry will work with the steel industry on identifying opportunities for increased recycling while decarbonizing both sectors. 

The paper will provide an overview of sustainable production, use and recycling practice for zinc in its use as corrosion protection for steel. This includes decarbonization, mitigating effects of climate change, circularity, and responsible sourcing. Examples from sustainable production at Hindustan Zinc Ltd. round off the paper.

A numerical simulation procedure is proposed for analyzing the partial replacement of pulverized coal injection by hydrogen, oxygen, and blast furnace gas (BFG) injections mixed with pulverized coal (PCI) within the tuyeres of large blast furnaces. The massive use of hydrogen-rich gas is highly attractive to the steelmaking blast furnace in the context of carbon net-zero hot metal production. Likewise, this new approach allows for increasing productivity and decreasing the specific emissions of carbon dioxide toward a net-zero carbon ironmaking technology. Nevertheless, pulverized coal injection gas mixture is a complex technology, in addition to the impact on chemical reactions and energy exchange, the internal temperature and gas flow pattern can also change drastically. With a view to assessing the state of the furnace in this complex operation, a comprehensive mathematical model using the multiphase theory was developed. The model simultaneously handles bulk solids (sinter, small coke, pellets, granular coke, and iron ore), gas, liquid metal and slag, and coal powder phases. The associated conservation equations are formulated for momentum, mass, chemical species, and energy while being discretized and solved using finite volume techniques. The numerical model was validated against the reference operating conditions using 220 kilograms per ton of pig iron (kg/tHM) of pulverized coal. Therefore, the combined injection of different concentrations of fuel hydrogen, blast furnace gas, and oxygen was simulated for replacing 40, 60 and 80 kg/tHM of coal injection. Theoretical analysis showed that the best scenario with stable operation conditions could be achieved with a productivity increase of 20% corresponding to a CO2 reduction of 15% and 60 kg/tHM of PCI replacement

Samarco has been using advanced process control with proven benefits, recognizing that the use of these technologies is a constant necessity. In the main stages of the production process, the "Advanced Process Control System" (SCAP) is employed, which consists of a multivariable control based on conventional control tools and fuzzy logic, simulating human thinking in decision-making.

SCAPs are computer programs that incorporate specific tools and knowledge to solve operational tasks, controlling the processes autonomously and intelligently. The practices and expertise of specialists are incorporated into the systems through the control strategy, usually aiming to stabilize and optimize the production processes. The strategy is composed of models and rules, constituting the intelligence of the system for decision-making.

The expert system maximizes the profitability of the operation of the most important equipment involved, from the iron ore beneficiation to the fired pellet. These systems automatically receive information from the controllers and use various advanced techniques to generate new appropriate set-points for the process at a very high frequency. These set-points are established to continuously pursue the objectives of Samarco's control strategy in different stages of the production process.

In the flotation stage, where the ore is separated from contaminants such as silica, the control method that best reflects the strategy and produces the best results is fuzzy logic, which consists of a set of rules that reproduce the best operational practices. Accompanying the expert system is the foam image analysis system, which measures the drag velocity, crucial for control. Another established and patented technology used by Samarco is the online silica analyzer, which provides information about the silica trend in the concentrate, as well as X-ray analyzers, which provide the iron trend in the tailings. These tools have contributed to maximizing the metallurgical recovery in conventional flotation and reducing the variability of silica content in the final concentrate. The main objective was to maximize the metallurgical recovery in conventional flotation and reduce the variability of silica content in the final concentrate. Combined with the foam image analysis system and the online silica analyzer, the tool has proven capable of achieving the expected objectives, bringing stability to the process, standardizing operations, and reducing input consumption by approximately 17.78%.

In the filtration stage, vacuum pressure and the number of pumps are adjusted to achieve the appropriate moisture level for the pelletizing stage. SCAPs play a decisive role in adjusting vacuum pressure and automating filter rotation cycles to optimize moisture and process productivity. In addition to reducing variability, there has been a reduction in moisture of approximately 2.26%. 

In the iron ore green pellet formation, it is a dynamic process with complex control requirements. In manual control, the local operator is responsible for process adjustments, and the timing and proportion of their actions depend on individual perception. With the implementation of the pelletizing SCAP, were achieved automated, standardized, and optimized control of the green pellet growth rate on the pelletizing discs. After implementation, there was a reduction in pellets out of size specification, a reduction in input raw material’s consumption, improvement in the quality of the final product and high productivity. The variability was reduced by 37.4%, the size range of 8 to 16 mm was increased by approximately 1.15% and productivity increased by approximately 6.1%.

For controlling the variables in the pelletizing plant’s furnace, the SCAP's actions determine the optimal configuration of the fans based on the temperatures and pressures of the wind boxes. The controller also optimizes the ideal burning profile based on the grate feeding rate. The result is a reduction in variability with an improvement in the physical quality of the burnt pellets. Variability was reduced by 49.8%, specific gas consumption decreased by approximately 19.58%, and thermal consumption decreased by approximately 10.54%.

Optimized decision-making improves process control by reducing variability and shifting averages towards operational limits. The observed benefits include capacity/production optimization, yield optimization, loss reduction, cost reduction, improvement in the quality of the final product, environmental compliance, and others.

This article aims to describe how SCAP processes input information through conventional calculations and statistical calculations combined with "crisp" and "fuzzy" rules in order to reduce variability in the main stages of the production process.

One of the biggest contaminants of soil, groundwater and surface water - leachate - also called percolated liquid, is the result of the enzymatic action of microorganisms and products resulting from the degradation of waste and water infiltration in landfills. This can prejudice the health of the population nearby the area. This study aimed to evaluate the implementation of a leachate treatment method (liquid from the decomposition of waste landfilled in the municipality of Conselheiro Lafaiete, Minas Gerais) with a focus on cost reduction and environmental improvement. The study was carried out during two years in Ouro Preto. We had studied a huge number of bibliographical references that portrayed about microwaves, alternative treatment of slurry and various subjects about it. Then, a composite sample was collected from the stabilization pond (inlet) and a composite sample from the output pond. The collection was carried out at three different points of the exit and entrance lagoon of the Sanitary Landfill in Conselheiro Lafaiete. Experiments were carried out with microwaves, organic coagulants and vertiver grass after treatment of manure in microwaves. The following parameters were analyzed: pH, BOD5, COD, Nitrate, Total Solids, Total Nitrogen, Phosphorus and Dissolved Oxygen, Total Aluminum, Total Lead, Total Copper, Total Chromium, Total Nickel, Total Zinc, Total Iron and Manganese, before and after the alternative slurry treatment. Among the results presented in this work, vetiver grass (Vetiveria zizanioides), when cultivated in a hydroponic system, is a plant with possible potential for phytoremediation of leachate leachate.

Following a brief description of the background, a life timeline of industrial and scientific activity during 48 years will be presented. It will cover first  the work done for more than 2 industrial companies including Acesita and Mannesmann and the successes achieved during that time such as the development of the first fluid system to inject charcoal in the blast furnace and it’s successful industrial implementation as the first Powder Charcoal System implemented with success worldwide.

The scientific activity at UFOP will follow along with the successes achieved such as participation in the Excellence Program of CSN (Companhia Siderúrgiac Nacional) as a visiting professor.

The establishment during thirty years as professor, researcher and Scientist of many collaborations with the best universities and professors in the world and especially in Asia will be described.

The successes achieved as the first researcher worldwide working with biomass (waste from the Agriculture) and biogas in the blast furnace will also be described.  Life learned lessons  will also be described.

The rupture of Brazil's Fundão Dam in November 2015, known as the largest environmental disaster in the country's history, resulted in the immediate release of approximately 40 million cubic meters of iron ore tailings into the environment. This catastrophe had widespread and devastating effects, contaminating water bodies, disrupting ecosystems, displacing communities, and raising long-term health and environmental concerns. It underscores the necessity of stringent safety measures and responsible environmental management in the mining industry and the ongoing need for remediation and restoration efforts.

The present study sought to evaluate the relationship between sediment characteristics and land use within the Water Resources Planning and Management Unit (UPGRH) of the “Piranga River”, Minas Gerais. This river represents one of the most crucial sub-basins of the “Doce River” in Brazil. The Piranga River was the first basin affected by the Iron Dam Break. Sediments in this context are complex geochemical entities that yield information essential for understanding the interactions of various processes occurring in fluvial environments. They originate from both natural soil weathering processes and anthropogenic activities, making them integral components of the watershed.

Bottom sediments serve as indicators of the environmental impacts resulting from the improper disposal of domestic and industrial effluents in ecosystems. This study entailed two campaigns conducted in June 2019 and March 2020, during which a total of 14 samples were collected from pre-defined locations within the UPGRH of the Piranga River. This area had been significantly affected by a dam disaster involving the mining company Samarco in the municipality of Mariana, Minas Gerais. Subsequently, the collected samples were subjected to drying, homogenization, sieving, and digestion processes. The grain size analysis results, obtained for both dry and rainy seasons, revealed that sediments from the region affected by the Samarco disaster exhibited finer grain sizes compared to those from unaffected rivers that were also assessed. This grain size analysis corresponded with the specific land use in these areas, as exemplified by the sampling point in the Casca River, which featured a coarser sand-related grain size and was known for such activity.

In summary, this research aimed to elucidate the extent to which human activities within a watershed can impact water quality and, consequently, sediment quality.

It is a well-known fact that steel is an important material used in many engineering applications, such as in the automotive industry, construction and machinery industries. In addition, desulfurization is a crucial process in steelmaking, since sulfur is an undesirable chemical element in steel’s composition. Although it results in better quality steel, it leads to a non-green slag that if not handled correctly may harm the environment. This study has the goal of discussing the process of desulfurization of hot metal in torpedo cars using CaC₂ (calcium carbide) based desulfurizer and presenting the introduction and the possibility of reusing the slag in other green applications. Desulfurization is a pre-treatment that removes the sulfur located in hot metal throughout the chemical reaction of the desulfurizer injected in molten metal inside of the torpedo car.

Therefore, after collecting the desulfurization slag from a local industrial process, the analysis of its properties starts, which was conducted using proper tools such as Scanning Electron Microscopy and also using X-Ray Diffraction and Fluorescence Analysis. In such manner, there will be a complete description of the slag's characteristics, which will lead to discussions about making the desulfurization’s slag disposal a greener alternative, such as implementing other uses like agriculture.

A numerical simulation procedure is proposed for analyzing hydrogen, oxygen, and blast furnace gas (BFG) injections mixed with pulverized coal within the tuyeres of large blast furnaces. The massive use of hydrogen-rich gas is highly attractive to the steelmaking blast furnace in the context of carbon net-zero hot metal production. Likewise, this new approach allows for increasing productivity and decreasing the specific emissions of carbon dioxide toward a net-zero carbon ironmaking technology. Nevertheless, mixed gas with pulverized coal injections is a complex technology with drastic changes in the inner temperature and gas flow patterns, beyond their effects on the chemical reactions and energy exchanges. Focusing on the evaluation of inner furnace status under such complex operation a comprehensive mathematical model has been developed using the multi-interactions of phases theory. The model treats simultaneously the lump solids (sinter, small coke, pellets, granular coke, and iron ores), gas, liquids metal and slag, and pulverized coal phases. The governing conservation equations are formulated for momentum, mass, chemical species, and energy simultaneously discretized and solved using the finite volume technique. The numerical model is verified against a reference operational condition using pulverized coal of 195 kilograms per ton of hot metal (kg/thm). Thus, combined injections of varying fuel hydrogen, BFG, and oxygen concentrations are simulated for 180 and 220 kg/thm of coal injection. Theoretical analysis showed that stable operations conditions could be achieved with a productivity increase of 53%. Finally, we demonstrated that the net carbon utilization per hot metal ton decreased to 15%.

The shaft furnace known Midrex is used for the production of direct reduced iron with the use of reformed gas. Another process based on shaft reactors is the Tecnored process, which exhibits the great advantage of using self-reducing agglomerates. Therefore, it was proposed a combination of the shaft furnace for direct reduction with self-reducing pellet burden. In addition, with the aim of improving the furnace efficiency and reducing the need for reformed gas, the injection of natural gas and oxygen into the bustle region is proposed. Thus, it is possible to exploit the advantages of direct reduction involving high amounts of hydrogen and faster reactions of the self-reducing process to decrease the CO2 emission, compared to that of blast furnace. The energy profile, productivity, and carbon emission of the traditional shaft furnace were compared with the simulated results after partial replacement of the burden with self-reducing pellets containing fines of elephant grass charcoal. The simulation results for a combination of 15% of self-reducing pellets in the burden with 3.5% oxygen and natural gas injections were the best among the scenarios simulated, with the productivity being 2.9 ton/m3/day and the decrease in the amount of reformed gas being 18%.

The increase in the added value of the product from the steel making process, in the production of steel and different rolled products for the various industrial sectors, together with actions to reduce CO2 emissions. The demand forecast for 2050 is considers and must be ensured by a 100% renewable system [1]. The transition to a 1.5-2°C world will fundamentally change exiting the resource flows of both metals and fóssil fuels [2]. It has been shown to be an option for the viability of environmental protection projects, such as way to improve the profitability of the activity. Within this scenario, biomass has been presented as a source of energy of great utility, when it comes to renewable sources like the sugar and alcohol mil cogeneration systems and industrial and service sector [3]. The circular economy and low carbon or by the reduction of natural gas itself with CO2 sequestration in the process. It can only ever be one of a range of sustainability orientated initiatives that manifests in the here and now [4].
Demark utilizes the greatest proportion of agricultural wastes for power generation at 16.8%, followed by Finland (15.6%), Brazil (8.4%) [5]. The conversion of biomass energy into heat, using steam-generating boilers, presents adequate yields, when used together with gases produced internally by the process, since it provides energy in a form that is easily usable by the steel making process, either in the form of steam. for use in industrial processes or for sending air to blast furnaces or for generating electricity.
Biomass has 45% carbon, 42% oxygen, 5% hydrogen and 8% other minerals in its composition. The feasibility of using biomass in Brazil as fuel in steam generating boilers requires a comprehensive and conclusive study, in relation to the real influence on the agricultural process, the carbon market and other sources such as biogas.
Faced with the scenario of viability of consumption of this source in steam boilers, the context of Brazil and a vision of the current scenario of consumption of biomass. It will be like a discussion to the theme.

The major thrust of global efforts to decarbonize global steel production aims at the transition from blast furnace/BOF steel production to electric furnace (EAF) steel production with the EAF fed by various combinations of DRI (direct reduced iron), HBI (hot briquetted iron), “green” pig iron and scrap. The challenges start with the observation that circa 60 % of global stee; production is in the Asia-Pacific area where most of the BF/BOF facilities are less than 15 years old; thus, too early for retirement (financially) and extend to the dominant Australia iron ore base that is not suitable for DRI/HBI shaft furnace use. For the rest of the world, the challenges include the CAPEX/OPEX requirements for high grade ore beneficiation, pellet plants, DRI/HBI plants and EAF facilities as well as the associated raw material challenges: iron ore quality, pellet availability, biomass consistency, scrap quality, and the cost of “green” reducing gas: H2 produced from renewable energy. The potential solutions to the above challenges will be outlined.

The revolution of industries provided the increase and speed of productions, mainly the production of steel [1]. In the specific context of shipbuilding, the use of steel plays a fundamental role in the design of vessels. Despite being a 100% recyclable material [2], there are few incentives for this practice in the sector. This is due to the predominant linear production model, where waste is still seen as a worthless by-product that cannot be reused. In this sense, the use of steel from scrap recycling, inserting it in the construction phase of vessels, emerges as one of the ways to promote the circular economy and guide the adoption of good construction practices for this sector. This paper intends to identify Transpetro's fleet of oil tankers and estimate the total steel demand for the construction of Suezmax class oil tankers. Based on the data collected, an analysis was made of the possible impacts caused if this fleet were built exclusively with recycled steel[3]. The article discusses if Transpetro [4] has any decommissioning fund and/or sustainable decommissioning planning, aiming to guarantee the reinsertion of the steel from these vessels in a new production cycle. It also discusses fiscal policies [5] that encourage the reinsertion of steel in the shipbuilding chain and how legislation has cooperated or delayed circularity actions in the sector. We will see that by incorporating circularity practices in this industry it will be possible to dissociate the construction process from the practice of extraction of new natural resources, resulting in the reduction of operational costs, promotion of the ship steel recycling market, and the environmentally correct disposal of this waste. Contributing significantly to the preservation of the environment and the reduction of Greenhouse Gas (GHG) emissions.

The current economic development model in global society has been progressively contributing to environmental degradation. It was intensified after the Industrial Revolution and is based on the linearity of extraction, production and waste generation[1]. This problem is particularly felt in the construction industry, responsible for a significant percentage of waste. Responses to this process include the proposition of a circular production economic model, according to which products should be designed to be reused, remanufactured, refurbished, and recycled, serving as input for a new production process[2]. This paper explores circular economy [3] approaches focused on the construction process. It proposes to develop a method for analyzing circularity practices and processes for the sector. It seeks to identify stages of construction practices considering the possibility of transition from linear to circular systems. To this end, the research developed a system of indicators [4] [5] to evaluate practices in relation to circularity parameters explored in the literature. This indicator system was applied to eight cases of construction companies operating in the state of Rio de Janeiro, which were invited to participate in the research. The findings suggest indications of different stages in the industry's transition to circular production.

Polyhydroxyalkanoates (PHA) are polyesters produced by bacteria. Furthermore, they are fully biodegradable, representing a rapid degradation response. Bacteria can accumulate PHA from sewage sludge, as there is a significant percentage of carbon-based materials in this waste; such as cellulose, PHA, lipids and fatty acids.

With the evolution of studies related to PHA, it is possible to improve its production method. In this way, the polymer will be a very good alternative for the production of bioplastic, as in addition to being a biobased product, it is also biodegradable.

The sewage sludge is a product from the waste water treatment plants. The treatment of this product is required to lessen the impact of wastewater disposal. This process requires a certain amount of energy that could be saved with sustainable technologies. As an option, sewage sludge can be used as a raw material for other activities. As is the case with PHA production, sewage sludge is very useful as it contains carbon-based materials, which will serve as a medium for the production of bacteria.

This project is a life cycle analysis of two PHA production paths that use sewage sludge as raw material. The first production mode uses a Dimethyl carbonate (DMC) solvent to extract the polymer from the bacteria, after which the sludge undergoes an enrichment and accumulation process. The second mode of production skips this process, making a compounder of the polymer with the biomass.

To compare the two routes, an analysis was made of the resources used, such as energy, water and, in the case of the first route mentioned, the use of solvent. The amounts were applied in the Gabi software. Gabi is an abbreviation of the German word Ganzheitliche Bilanzierung, which literally translated means holistic accounting. GaBi is a software used to facilitate the creation of a lifecycle analysis plan. Using this platform, it is possible to understand the carbon footprint of a product, optimize the process and, in the case of a company, gain market share

It is concluded that the process of direct extrusion, having as output a compounder rich in biomass. is the most sustainable option for PHA production.

Samarco’s iron ore concentration process consists, basically, of the following steps: crushing, screening, grinding, desliming, coarse flotation, fine flotation, regrinding and columns flotation. After the mill, an ultrafine material rich in iron is generated and, after the desliming step, this material is discarded in actually disposed in a pit. The main idea of ​​this study is to develop a new co-product to be used as a raw material in steelmaking processes. The challenges were the low levels of iron and high levels of silica and alumina, incompatible with the products offered on the market, and the granulometry of the ultrafine material (70% of mass passing through 10 micrometers). To make the product more attractive to the market, it was necessary to develop a magnetic concentration process for the ultrafine ore, increasing its iron content with adequate mass recovery. The iron content in the concentration product is inversely proportional to the mass recovery and the amount of material to be disposed of in suitable structures. After the concentration stage, the ultrafine material passes through a dewatering stage in thickener and press filter route, resulting in an ultrafine pellet feed with ideal humidity for agglomeration in discs, intensive mixers or extruders. The agglomerates can be heat-treated in a travelling grate furnace or be produced with a cold bonded binder, to acquire physical strength for handling and transport to customers. There will be an increase in the overall metallic yield of the process and a significant reduction in the area required for waste disposal, increasing sustainability and reducing business risks.

Sekisui Chemical has been developing technologies to efficiently convert CO₂ to CO with Reverse Water Gas Shift (RWGS) reaction by Chemical Looping(CL).
Among the various CO₂ utilization approaches, the RWGS reaction plays a pivotal role, since it produces synthesis gas (syngas or CO + H₂), the building block of numerous conversion processes. Average CO generation yields are 40~60%¹ with conventional RWGS. Introduction of metal oxide as an Oxygen Storage Material (OSM) would bring the RWGS reaction further by splitting the reaction itself into a reduction and oxidation reaction, referred to as a RWGS-CL, an intensified version of the conventional RWGS. By switching the gas flow between at least two reactors after the OSM is reduced or oxidised, respectively, a quasi-continuous process can be achieved, which is more efficient compared to the classical RWGS as it yields partially separated gas streams, simplifying the downstream gas separation. The CL technology developed by Sekisui has validated >90% CO yield and 80% H₂ conversion at demonstration with blast furnace gas in Spain², due to the non-equilibrium nature of the looping process, which can be employed to achieve high yield. This achievement is a result of NEDO's international joint research and development project (JPNP20005) in the field of clean energy.
In Japan, Sekisui Chemical has started a demonstration project to produce high-performance chemicals by combining this CO₂ to CO technology with the downstream bio-process from waste incineration plants, and plans to start a sales business of these high-performance chemicals produced from CO₂ derived from wastes in 2030³. In addition, Sekisui has started collaboration with Tokai Carbon in Japan for the purpose of manufacturing CO₂-derived carbon products using this CO₂ to CO technology⁴.
By applying the CO₂ to CO technology to CO₂-containing waste gas in steelmaking process, Sekisui hopes to contribute to CCU and decarbonization in steel plants.

Sinter Plant is a major contributor towards Emission of Suspended Particulate Matter(SPM) in an Integrated Steel Plant^[1]. Over the past decade, Sinter Plants at Tata Steel Jamshedpur (TSJ) have pioneered innovation starting from Raw Material handling,  ESP (Electrostatic Precipitator) maintenance and health monitoring, leading to achieving benchmark level stack reductions^[2]. Our journey from 425 kg/hr in FY’12 to < 100 kg/hr in FY’23 involved operational excellence, strategic maintenance practices and digital innovations including pioneering efforts in AI-ML. This paper elucidates the expedition of TSJ Sinter Plants in lowering dust concentration from stack from >75 mg/Nm3 levels to below 30 mg/Nm^3. This was achieved by establishing process innovations, control in raw material consumption and quality, enhancing maintenance monitoring of ESPs, and the use of HFTR (High Frequency Transformer Rectifier) units in sinter making. 

The strategy employed in TSJ plant revolves around three main pillars – People, Process & Technology. In the people front, level of awareness, alertness and responsible behaviour was inculcated by special training, incentive schemes and building a sense of belongingness to the problem. In the Process part, extensive use of research, understanding the cause of higher stack emission was done at the beginning. Big data analytics was applied on long term data showed that ESP inlet temperature, Temperature at Wind Box#10, ESP inlet suction etc played a big role. Accordingly process control loops were designed and implemented through algorithms based on statistical models and thermodynamic models. This unique feature of integrating the above models gave prediction of stack emission to the tune of >95% accuracy. Finally, this predictive models led to installation of some technological advances, such as HFTR, MFTR transformers. TSJ plant also developed a novel use of ESP dust, which was eliminated from its recycling to the sinter making process. 

As a result of the above three pronged strategy, the stack emission concentration could be reduced to a level of below 15 mg/Nm3, which is perhaps comparable to the World Benchmark for plants employing ESP only as waste gas dedusting method. TSJ has embarked on some more innovative technology, which will reduce the stack dust concentration below 10 mg/Nm3 with ESP alone. The paper will elucidate the complete journey and a success story of more than a decade, which will be worth sharing with the world.

The dynamic process models reported so far in literature have ignored the fact that there are critical points of change over to chaotic dynamics during the progress of blow in a BOF. These critical points usually change the path of the blow profile and lead to either dry slag formation or slopping. The end point values of phosphorus, carbon and temperature may be severely affected by the occurrence or critical points. Hence it is of great practical importance to track these points online. A discrete dynamic analysis of the blow, while being tracked by a discrete surrogate model, helps to reveal the possibility of occurrence of the critical point in advance so that a proactive action can be taken in time to avoid the critical point altogether or better manage the situation with time. The “slopping” indicators based on sound measurement do help but are too late to act upon. Chaos control is necessary during the blow for control of phosphorus, carbon, and temperature at tap.

The depletion of reserves of high-quality primary ore raw materials (quartzite, bauxite), the upward trend in the cost of coke, etc., presupposes an integrated approach to the use of mineral raw materials and coal mining products. Involving coal mining waste in the metallurgical process is one of the promising directions for organizing the production of complex silicon and silicon-aluminum alloys based on the electrothermal properties of high-ash carbonaceous rocks. The content of basic oxides in the ash of carbonaceous rocks, as well as the price, allows us to consider it as a cheap source of the corresponding elements in the composition of complex ferroalloys. The purpose of this work is to develop a rational resource-saving technology for the smelting of ferrosilicoaluminum using carbonaceous rocks. The technology for smelting ferrosilicoaluminum involves the use of high-ash coal waste with minor additions of quartzite without the use of coke. The process of reduction of silicon and aluminum is provided by carbonaceous rock. Waste carbonaceous rocks with an ash content of 
50-65% are a unique material and are a natural mixture of oxides of silicon, aluminum and carbon. The mineral component of the rocks is 92-96% composed of silicon, aluminum and iron oxides, and the sum of silicon and aluminum oxides is at least 89-90%. The content of SiO₂ and Al₂O₃ in the ash part is in the range of 55-60% and 30-35%, respectively. Coal mass in rocks, depending on ash content. is 20-34% with a content of up to 15-18% volatile compounds. This composition of carbonaceous rocks guarantees the production of a silicon-aluminum alloy with a silicon content of 50-65%, aluminum 10-30% and the rest iron [1-3]. The alloy is smelted in ore-thermal electric furnaces with a constant loading of charge materials and periodic release of smelting products - alloy and slag, and the amount of slag does not exceed 3-5% of the weight of the alloy.

Titanium nitride films were deposited onto SUS304 substrates under various film thickness, deposition temperatures, and substrate bias voltages. Their protective quality was evaluated by electrochemical testing in accordance with the critical passivation current density (CPCD) method. Two types of tests were employed to evaluate corrosive behavior of coated substrates: a high-temperature and high-pressure corrosion test; and a measurement of the change in anodic current density with immersion time. A scanning electron microscope was used to examine surface morphology and fractured cross-sections of the films. Residual stress in the films was determined by the sin2 method. An increase in film thickness engendered high protective quality. That protective quality was improved with increasing deposition temperature; micrometerorder pores were observed on all parts of films deposited at lower deposition temperatures, whereas few pores existed on films deposited at higher temperatures. This result indicates that these pores are one factor influencing overall protective quality. A film deposited with no substrate bias voltage displayed morphology with a typical columnar-structure; it also demonstrated complete protective quality. As the bias voltage increased, protective quality deteriorated, whereas an excess increase in the bias voltage gave rise to a slightly higher protective quality. Films with lower compressive stress had only a few pores and possessed higher protective quality, suggesting that pore formation originates in compressive stress. Corrosion tests indicated that the coated substrates corroded more rapidly as compressive stress in the film increased. The effect of compressive stress on maintenance of corrosion-protective quality was treated quantitatively. The rate of increase in the exposed area of the substrate was estimated from variation of an anodic current density with immersion time. This evaluation indicates that a decrease in compressive stress contributes greatly to maintenance of protective quality.

Climate change and environmental impacts reflect the externalities of a global model of unsustainable production and consumption. However, even in the face of a chaotic environmental scenario, the exploitation of resources and consequently Greenhouse Gas (GHG) emissions continue to increase, thus causing an increase in temperature and possible irreversible impacts on the planet. The Circular Economy presents itself as a tool for mitigating extraction and cooperation for efficient resource management, avoiding waste ^[1] . Currently, the transport sector is the main responsible for Greenhouse Gas (GHG) emissions, making the transformation of this sector's value chain urgent^[2] . In a national context, motor vehicles are the main means of transport used, in the year 2022 there were approximately 115 million vehicles registered in Brazil. Revealing the expressive growth rate compared to 2010 data, with approximately 65 million vehicles circulating in the national territory^[3] . A study carried out in 2018 shows that the transport sector was responsible for 23% of the total amount of CO₂ emissions worldwide in 2017. In addition to being one of the world's largest consumers of oil^[4] . The 100% electric vehicle therefore appears as a promising solution to this scenario of mitigating air pollution, especially in urban centers where its concentration occurs. This article proposes to develop a method for collecting and analyzing the characteristics observed by consumers when choosing their own vehicle. It seeks to identify stages of awareness and the transition movement between internal combustion vehicles and 100% electric vehicles. To this end, the research developed a form via Google Forms aimed at evaluating the parameters used by consumers when considering the possibility of migrating to 100% electric models. This form was applied to seventy-six (76) citizens living in the State of Rio de Janeiro, invited to participate in the research. The findings suggest evidence of different stages of awareness and acceptance regarding the transition to 100% electric vehicles. Thus, one of the solutions proposed by this work is the transition from internal combustion vehicles to electric vehicles fueled with ethanol, which, in addition to contributing significantly to reducing dependence on fossil fuels, encourage the search for renewable energy sources such as those coming from of biomass. In order to positively impact the scenario of GHG emissions caused by the sector.

FeSiMn is a ferroalloy that contains iron, silicon and manganese as its main components. It is widely used in the steel industry as an alloying additive to improve steel properties. In the manufacturing process, the charge of ores and other materials is fed into the furnace. The furnace is heated and melted by means of heat generated by electric current in electric reduction furnaces. During the reduction reaction, manganese is reduced by the carbon and combines with the iron and silicon present in the charge, forming FeSiMn.
An electric reduction furnace is a piece of equipment that uses electricity as an energy source to heat and melt the load of ores and reducing agents. In this type of furnace, electrical energy is supplied by electrodes that are inserted into the furnace. Electric current passes through the electrodes and creates an electric arc, which generates intense heat. This heat is used to heat and melt the charge of ores and other materials.

FeSiMn from Granha Ligas in Conselheiro Lafaiete, Minas Gerais, is produced in an electric submerged arc furnace. In 2022, in order to increase the productivity of Furnace 1, a renovation was carried out in September and November 2022 to resize it, redefining its design parameters, such as diameter and spacing between electrodes, furnace diameter and power density.

For the present work, geometric parameters of the furnace were changed, such as spacing between electrodes and crucible area, in addition to other variables. Subsequently, the post-renovation productivity gain and parameter redefinition were analyzed, reaching an increase of almost 33% in production per ton/hour, in addition to a 3% reduction in specific energy consumption, demonstrating the importance of the kiln's geometric relationship and its productivity.

There is currently in the mining industry, as well as in other industries, a movement seeking to increase investments in decarbonization processes to help combat global warming. Among some initiatives taken is replacing diesel-powered mobile equipment in the mines with electricity-powered equipment, such as electric off-highway trucks or even belt conveyors in the mining operation. Samarco is a Brazilian mining company that, since its conception, has used a conveyor belt mining system in its mining operation, using only a small number of trucks to complement the mining process. This mining process that combines conveyor belts and trucks has brought environmental gains for the company, since the environmental impact of conventional truck-only mining is greater than that of the combined system. To measure these gains, a medium-term mining plan was developed in which two fleet scenarios were detailed. One scenario contemplated a high level of detail of belt mining seeking its maximization, while the other considered the operation performed 100% by trucks, eliminating the use of conveyor belts. Through the comparison of these two scenarios, it was possible to make an inventory of atmospheric emissions and greenhouse gases for each one of them, considering data such as types of equipment, diesel consumption, total distance travelled, and energy consumption. The results showed that the fleet scenario with conveyor belts results in periods with up to 15% less greenhouse gas emissions and 37% fewer total particulates compared to the truck-only scenario. Therefore, the results confirm the environmental benefits of the method and the need to look for ways to even expand it in future operations through a study to identify the potential areas in the long-term mining plan.

FLOGEN Technologies Inc. has developed an integrated Design/Decision-Making/Control/Optimization/Automation System combines several needs on supply side, on production side, on metal sales side and on financial side. It supports cost prediction and cost follow up on the energy and consumables side and is integrated with databases that manages numerous types of essays. This has been at various blast furnaces of pig iron. The system instantaneously makes a complete optimization of all raw materials, including limestone, silica, air and oxygen volumes, in order to achieve specific targets according to the needs of the company. The main achievements of the implementation of the FLOGEN CONTOP system were the increase of the pig iron production by about 14% and the decrease of total consumption of charcoal (breeze and fines) by about 4%. Additionally, fines injected through the tuyeres were decreased, temperature and composition of slag and pig iron (including Si and P) were better controlled and silica addition as a flux was minimized. An overall instantaneous mass and energy balance helped fix various mechanical and procedural problems in the plant. CONTOP system was also successfully used to determine the annual procurement strategies by predicting various raw material cost-based scenarios related to productivity and fuel consumption in short- and long-term future. CONTOP increased productivity and reduced cost up to the highest designed limit of the technology. CONTOP also changed the way of operating from a reactive wait-the-lab-results-approach to a proactive forecast-and-act approach.

One way for energy storage is hydrogen production of the excess of electric energy. However Hydrogen storage is quite complicated because hydrogen is only liquid at 20 Kelvin. Also, as easily explained by the Carnot cycle, there are losses along the several steps of liquid hydrogen production, as for example, hydrolysis efficiency, compression and liquefaction efficiency, and so on.
However, excess electric energy can be transformed into hydrogen and immediately used for metal reduction. Here it is discussed the technical and economic feasibility of using hydrogen for iron reduction.
Oil importer countries may turn to hydrogen usage in industry, thus avoiding oil price fluctuation, or also coal price fluctuation. Even with higher prices, the use of hydrogen in metallurgical processes gives alternatives to non-renewable commodities. This detail is relevant for strategic planning of governments.

The role of mathematical models in improving the technology of blast furnace melting is shown [1]. Examples of new developments of the Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences in the field of digital models of blast furnace production are given, in particular, two-dimensional and three-dimensional mathematical models of the thermal state of various zones of the blast furnace [2, 3]. New developments in the field of analysis and control of various thermophysical and physico-chemical phenomena occurring in various zones of the blast furnace allow us to raise the technology and methods of conducting blast furnace melting to a fundamentally new level, allowing us to save fuel and energy resources. The possibility of using a digital model at a pace with the process when using sensor readings through the database management system of the blast furnace shop of the enterprise is shown.

This paper considers the possibility of using and improving the mathematical model of heat exchange of the blast furnace process, taking into account the injection of synthesis gas (with different amounts of hydrogen in it) [1-3]. The analysis of existing models of heat exchange of a blast furnace is carried out and arguments are given justifying the need to take into account the characteristics of synthesis gas in the model. In a blast furnace, additional hydrogen in synthesis gas can be used as a partial replacement for coke, which will reduce the amount of carbon dioxide emissions into the atmosphere and increase the energy efficiency of the process. The use of synthesis gas in a blast furnace has a number of advantages and disadvantages. However, when analyzing the current environmental situation, it should be noted that the technology of using synthesis gas has great prospects. Calculations based on the improved model showed a more accurate assessment of the heat transfer characteristics in the blast furnace process when using synthesis gas. The results of the study can be used to effectively optimize the parameters of technological processes in blast furnace production.

Iron ore sintering is a high temperature, high volume process for producing raw material for blast furnace, and the quality requirements for sinter is high strength and Tumbler index, good reducibility and reduction degradation index (RDI). The process involves high temperature gas-solid reaction, drying and condensation, and melting and solidification phenomena. Simulation of the iron ore sintering process reveals considerable variation in thermal and melting profile in the sinter bed [1,2].  Melting is very low in the top critical zone just below the ignition hood, giving rise to low sinter strength and high return fines, where as in the bottom layers melting is much higher, producing glassy phase with low reducibility. 

Suction pressure applied in the wind boxes for gas velocity in the sinter bed is one of the important process parameter for the sintering process, which is optimized here in three locations, top, middle and lower zones by optimization technique such as Genetic Algorithm (GA), for better melting and sinter quality in the three zones representing the total sinter strand [3].

Sinter quality which is combination of high strength and good reducibility, can be attributed to partial melting of about 30%, in the sinter bed. However due to non-uniform combustion zone in the sinter bed, melting is very low in the top critical zone, whereas melting is much higher in the lower regions. Therefore, to overcome this non-uniform melting along the sinter bed height, two-layer sintering process is envisaged with higher coke rate in the top layer, and lower coke rate in the bottom layer. The two-layer sintering process have been optimized by using Multi-Objective Genetic Algorithm, with different coke rates in the top and bottom layers. The thickness of the top and bottom layers are also varied for optimization. The two objectives for optimization are uniform 30% melting throughout the sinter bed, along with minimum overall coke rate, giving rise to two conflicting objectives for Pareto optimization [4]. The lower coke rate in the bottom layer up to the Burn through point (BTP), gives additional benefit of reducing pollution and greenhouse gases [2,5] like CO, CO₂, SOx, and toxic gases such as NOx, dioxin and furan.

The drying process of iron ore pellets in the travelling grate pelletizing furnace is carried out through the transfer of heat from the hot gas by convection, with gaseous flows that initially occur upwards and then downwards, through the bed of pellets. The furnaces are designed according to the characteristics of the iron ores. However, over time, changes occur in the iron ore mineralogical characteristics that strongly affected the process kinetics, making the process inefficient. At Samarco, after the exhaustion of the Germano mine, the hydrated iron ore were incorporated into the process, mainly with the mineral goethite, demanding a greater input of thermal energy. In addition to removing the free moisture in the pellets, it was also necessary promote the thermal decomposition of goethite. With the aim of improving the drying process of iron ore pellets, especially in older furnaces, studies were carried out evaluating the effects of microwave irradiation in the drying process. Initially, laboratory experiments were carried out with homemade equipment (frequency of 2450 MHz and power of 1,000 W) for small samples of pellets, and then in a semi-industrial equipment (frequency of 915 MHz and power of 18 kW) for a greater mass of pellets. The study investigates the use of microwaves in the iron ore drying process and the effect on the green pellets quality.

Mining attracts a lot of investment and has a good financial return. And this potential of the sector was already visible since the period of colonial Brazil. At that time, the extraction of minerals was responsible for part of the occupation of the national territory and, mainly, for the economic balance and generation of wealth. However, the accidents that occurred after the collapse of mining dams in Brumadinho and Mariana attracted people's attention to seek ways to avoid environmental damage like this without harming the mining sector, which drives the country's economy due to the generation of jobs and to the production of items essential to people's daily lives, such as cars, computers, cell phones and household appliances, for example. The present work presents a bias that is related to Brazilian Law in the sense of stipulating standards on the subject and to Materials Engineering that works in the reuse of waste to make new materials, both areas working together and uniting the efforts that have been intensified to prevent and remedy environmental impacts.

The large scale industrial processes involved in Iron and Steelmaking are very complex in nature and very much challenging to understand. A lot of modeling and simulation efforts have been made by numerous workers in the past to have an insight of the process and predict the behavior of the process due to changes in operating parameters and raw material conditions. The iron and steelmaking processes involve dynamic interaction between various phases namely slag, metal, gas and solid, existing altogether at very high temperatures, along with other coupled phenomena like dissolution of solid charge/scrap and fluxes. The overall modeling of such complex reactor involves chemical reaction thermodynamics calculations at interface as well as mass transport rates considering the nature and behavior of fluid flow and diffusion processes.

Such complex process could be modeled very effectively by coupling of slag/metal, metal/gas and gas/solid reactions using multicomponent mixed transport-control theory [1]. 

In the overall sense, the thermodynamics and mass transport based kinetic limitations inside the reactor are integrated together in an intelligent manner depending upon the mixing behavior and mass transport characteristics across various regions inside the reactor. 

A multireactor-based approach and multicomponent mixed control method as explained above was used to model BOF Steelmaking process as well as MIDREX Process. The macro programming capability of FactSage [2] was used to program such models in an innovative manner which was also validated by using the data from Steel Plant (JSW Steel Ltd.). In BOF Steelmaking Process, This approach was used to study the decarburization rates and their contributions coming from the jet impact (hot-spot) zone, slag–metal–gas emulsion, and bath boiling for different levels of mixing in the metal bath by variation of other operating parameters [3,4]. In MIDREX Process the model was developed by considering the process as a counter current reactor consisting of multiple conceptual reactors. The fraction of gas being utilized in each reactor zone is estimated using the kinetic considerations of the process. The overall kinetic effect involving the effect of mass transfer control in the gas, and solid product, along with chemical reactions at the interface of the unreacted solid surface were considered. The model was used to predict the carbon content, production rate and metallization for the given set of input variables [5].

This approach of modeling the large scale reactor process is very much effective tool as explained by the examples of BOF and MIDREX processes. The effect on CO₂ emissions and energy consumption due to various possible changes in the process operating strategies, parameters and raw materials could be studied very effectively with the help of such innovative models where they may act as an efficient guiding tool.

Phylum Mollusca is one of the richest phyla in living species [1]. Within this classification is the gastropod Melanoides tuberculata (O. F. Müller, 1774), with an operculum, which protects it from environmental weather [2]. One of the limiting factors for organisms is light, altering behavior, reproductive period and distribution [3].

This study aimed to observe the effect caused to Melanoides tuberculata by different types of lamps.

Samples of Melanoides tuberculata were sampled in Rio Grande, in Água Comprida/MG. In the laboratory, samples of five animals were separated in each aquarium with an approximate volume of 800 ml. The aquariums were aerated and the physical-chemical parameters of the water. Each of the six aquariums was subjected to a different type of light, one of which was designated as a control. The other treatments were UV lamp C; Ultraviolet lamp A; Incandescent lamp; Cool white compact fluorescent lamp and Warm white compact fluorescent lamp.

The physical-chemical parameters showed variations between treatments, but these were not significant. The Incandescent Lamp seems to have favored primary production. Animal survival varied significantly between treatments. When using the parametric test for analysis of variance, comparing the means of treatments; a “p” value equal to 0.000 was obtained, indicating a probability of less than one millionth that the differences were due to chance. Treatment with the UVC lamp determined the death of all animals. On the other hand, the treatment with the highest survival rate was the treatment with a warm white compact fluorescent lamp.

Nanocrystalline magnetically soft materials were discovered by Yoshizawa, Yamauchi and Oguma in 1986 [1, 2]. This was preceded by numerous research and development of amorphous magnetically soft materials, beginning in 1960. In order to obtain an amorphous structure, ultrafast quenching of a metallic melt with a cooling rate of about 106 K/s is used. Under industrial conditions, amorphous tape with a thickness of about 20 μm is produced using the flat jet method [3]. In scientific research, the amorphous Fe-B alloy is widely used in which boron acts as an element that promotes amorphization. For industrial purposes the Fe-Si-B alloy [4] is more suitable, in which silicon is additionally introduced to increase the crystallization temperature and reduce the coercive force.
The study of multicomponent melts shows that the structures of liquid and solid states are interrelated. The most homogeneous structure has the melt heated above the critical temperature, which corresponds to the temperature of structural transformations. Amorphous precursor obtained from homogeneous melt has greater ductility and hardness, higher enthalpy of crystallization. After nanocrystallization of the amorphous precursor obtained from the superheated melt, a material with higher permeability was obtained, which can be attributed to the increased proportion of small nanocrystals of about 2 nm.
Production of magnetic systems from nanocrystalline materials can be divided into several technological operations [5]. The initial operation is the melting of an alloy of a given chemical composition. This is followed by superfast quenching of the melt to form an amorphous precursor in the form of a ribbon with a thickness of about 20 nm. Thermal processing of the amorphous precursor should ensure the formation of a nanocrystalline structure with a guaranteed level of magnetic properties. As a rule, a magnetic curcuit or core is made from the amorphous precursor beforehand. In this paper the physical properties of nanocrystalline alloys in the liquid state, the influence of chemical composition on the nanocrystallization process, magnetic properties, in particular magnetic losses, and the application of magnetically soft nanocrystalline alloys, mainly for power electronics, are discussed.

The steel industry provides large quantities of raw material for the society at the cost of large emissions of CO₂, however, and thus contributing to the global warming. Therefore, it is imperative for the steel industry to undergo a transition to low-CO₂ ironmaking technologies within the next 5-10 years. In order to reach sustainable ironmaking, recycled hydrogen as a reducing agent is the most promising path to follow [1], although the traditional blast furnace (BF) and its H₂-intensive variant next to Midrex and Energiron will still play an important role during the transition process. However, independent of the applied technology, it is common understanding that a thorough knowledge of the governing process parameters is critical to the design, control and optimization. Experimental investigations are very limited due to harsh operating conditions and involved costs so that innovative simulation technologies are more than welcomed to gain a deeper insight into the underlying physics of these processes, for which the extended discrete element method (XDEM) has crystallised as the most promising road to follow [2]. It treats the iron bearing material and coke as a discrete phase with its descend in the reactor and thermodynamic state i.e. drying, reduction through carbon monoxide and hydrogen and melting of ore particles and coke oxidation while a coupling to traditional computational fluid dynamics (CFD) describes the fluid and thermodynamics in the void space between the particles including an exchange of momentum, heat and mass between the gas and particles. This versatile and unique technology allows applying XDEM to a large variety of ironmaking reactors to even represent them as digital twins and to support the transition to “green” steel. A thorough analysis of predicted uncovers the hidden complexity and contributes significantly to a deeper understanding and thus, promotes strongly a shift from current empirical-based practice to a truly advanced multi-physics simulation technology. Hence, information from digital twins is already available at an early stage of design avoids costly re-designs. Problems are identified before they even occur and down-times are reduced. These findings support decision-makers and help them to make informed decisions. Consequently, a faster time-to-discovery and time-to-solution is obtained. 

Following anode overpotential measurements and the derivation of the theoretical interrelationship between dissolved alumina concentration and cell voltage (constant current density) in the mid-1960’s, aluminium smelting technology cell designs shifted to central channel multi-point alumina feeding with two rows of prebaked anodes. While this enabled a dramatic reduction in perfluorocarbons (PFC) coevolution at the anodes. Since then cell sizes have necessarily increased  from ~80 kA to near 600 kA. With two liquid layers a necessary design feature, spatial variations in process conditions have re-emerged due to the kinetics of alumina dissolution, and the limited electrolyte volume. This has re-introduced limited PFC co-evolution under some operating conditions. Simultaneously, because of other cell design features, zones of high sodium co-deposition in the aluminium have resulted. The higher sodium levels lower the faradaic efficiency from previous achievable levels, as well as dramatically reducing the cathode life. From “autopsies” of cells that been prematurely cut out or undergone “early failure” it becomes evident that a redesign of the cell, coupled with better choice of structural materials, is necessary if the modern technology is to again achieve low energy consumption and maximum environmental responsibility. Illustrative examples will be used.

The big trend nowadays is the replacement of coal plants by wind and solar. This may affect the price of electric energy, enabling processes where the electric energy is relevant, as for example secondary metallurgy where arc furnaces have large applications.
Here we will discuss the impact of the new methods of energy generation on the cost of steel production in the next decades.
It is forecasted that the price of electric energy will continue high in the next 5-10 years, while the coal energy plants were not completely replaced by wind or solar. Also, energy storage is expensive , and this precludes price energy reduction. The high price of energy storage is a significant bottleneck concerning price reduction of energy. Energy can be exported as a reduced metal, and countries with surplus of electric energy can become exporters of metals for countries with energy deficit.
Brazil has one of the best conditions in the world for wind energy production in states near the equator line as Rio Grande do Norte and Ceará. These states are also promising places for production of other reduced metal, as for example aluminum.

The exhaustion of natural resources (quantity and quality) and CO₂ emission controls are becoming increasingly important in steel industry.  A lot of steel engineers studied various means to decrease reducing agent at blast furnace for reduction of CO₂ emissions.  For example, injection of waste plastics and carbon neutral materials such as biomass into blast furnace is better alternative. Especially, biomass has novel advantage, namely, no CO₂ emissions, because of carbon neutral. Production of carbon composite iron ore agglomerates having good reducibility and strength is becoming one of the most important subjects. 

     Carbon composite iron oxide pellets using semi-char or semi-charcoal were proposed in order to enhance the reduction rate of iron oxide.  The carbonization was done under a rising temperature condition until arriving at a maximum carbonization temperature T_c,max to release some part of the volatile matter included (V.M.).  Starting point of reduction of carbon composite pellet using semi-charcoal produced at T_c,max = 823 K under the rising reduction-temperature condition was observed at the reduction temperature T_R = 833 K, only a little higher than T_c,max (823 K), which was the aimed phenomena.  As T_c,max increases, the emitted carbonization gas volume increases, while the residual V.M. decreases, and, as a whole, the total heat value of the carbonization gas emitted tends to increase monotonically.

The mining industry seeks innovative and sustainable solutions for its production processes in the face of the international macroeconomic scenario. The Brazilian iron mining industry is among the largest in the world, with iron ore being one of its main export products.

The majority of Brazilian iron ore is found in the Alegria Complex, located in the state of Minas Gerais, Brazil. The geological context of this region includes the presence of friable itabirite formations. At greater depths, where weathering processes are typically less active, iron ore bodies tend to have lower iron content and higher hardness/compactness.

The use of iron ores with lower iron content and higher compactness, responsible for generating more waste during beneficiation, is occurring at a time when mining must develop technologies to reduce its environmental impact. As an alternative to depositing waste in dams, the sandy material can be filtered and stacked. However, the ultrafine portion (slimes) of the waste, which is rich in iron and not efficiently filtered through vacuum processes, possesses challenges and opportunities.

This study evaluated the effectiveness of adding different percentages of ultrafine iron ore (slimes) in the pelletization process as an alternative to its disposal as waste. The ultrafines are obtained during the ore beneficiation process, and their reuse was aimed primarily at metallurgical recovery during beneficiation, as they can contain up to 48% iron in their composition. The results of this alternative use is reduction in its potential as an environmental liability and the reutilization of this waste, promoting a more sustainable mining production by significantly contributing to the management of non-renewable resources. Additionally, this initiative makes the segment more competitive by utilizing low-cost raw materials.

The results of this study evaluates iron ore pellets produced from pellet feed incorporating high-specific-surface material, the ultrafine portion. Samarco’s pilot pelletizing plant conducted tests to assess the chemical, physical, metallurgical quality, and microstructural phase formation in pellets produced from different levels of specific surface area in the pellet feed. Degradation during handling tests of the pellets were also performed, considering resistance to surface and volumetric fragmentation due to impact. The results show the ideal process constraints for specific surface, loss on ignition, incorporation content of ultrafines, and chemical quality for pellet production within the highest standards of excellence historically practiced by Samarco, with significant gains in impact resistance and decrease of degradation during handling of the pellets.

Reheating of steel ingots in batch furnace such as soaking pit and box furnace, and Concast steel products like bar, billets and slabs in continuous furnace such as walking beam, and pusher type furnace is an important step for further thermo-mechanical processing like forging and rolling operations.  Concast Steel and ingots are heated up to 1100 – 1250 C, and since this is a high temperature and energy intensive process, excess heating time will cause productivity and energy loss, as well as oxidation or scale loss. On the other hand, if it is heated very fast causing high thermal variation between the surface and core temperature, will lead to thermal stress, distortion and crack formation. Furthermore, rapid heating without thermal homogenization can cause problems during hot rolling or forging operations, which may lead to, roll stuck, cracking and forging problems. Therefore, the aim of the heating process is to avoid any excessive thermal stress, particularly in the vulnerable ferrite to austenite phase transformation range, and also to achieve thermal homogenization with optimum time and energy efficiency.

To numerically simulate the process, a detailed two dimensional finite difference model is developed by using generalized axisymmetric equation, and Crank-Nicholson technique. To accurately simulate the process. The model also has to consider all the complexities of the process like anomalous behaviour of thermal conductivity of steel and latent heat of phase transformation. The model has been validated with limited number of Lab-experiments in a muffle furnace. Model based Process Control system have been developed for both batch and continuous reheating process, with Graphical User Interface (GUI) for plant application. 

Climate change is one of humanity's greatest challenges [1]. The effects of climate change on planet Earth are increasingly present in everyday life, causing environmental imbalances, thus strongly impacting the terrestrial ecosystem. According to the IPPC (The Intergovernmental Panel on Climate Change is the United Nations) [2] the increase in greenhouse effect emissions (GHG) is being caused by human activity, is causing climate change. Greenhouse gas emissions cover the Earth, trapping the sun's heat, generating global warming and climate change. Faced with this climate challenge, on December 12, 2015 in Paris, an international treaty was established to combat climate change, signed by 196 countries that committed to complying with the treaty as of November 4, 2016. The Paris agreement's main objective is to limit global warming below 2, preferably 1.5 degrees Celsius [3] . This climate action plan (Net Zero 2050) provides for the goal of zeroing net emissions of greenhouse gases by the year 2050), according to the International Energy Agency (IEA) [4] Steel is an essential material for the technological development of society. According to the International Energy Agency (IEA) [5] the steel sector, among the heavy industries, ranks first in CO2 emissions and second in terms of energy consumption. Iron and steel account directly for 2.6 gigatons of carbon dioxide (GT CO2) emissions annually, with 7% of the global energy system total. Based on this analysis of these studies, this work aims to analyze the processes of decarbonization of the steel sector for the production of sustainable steel and its contribution to the reduction of carbon dioxide in the atmosphere, meeting the goals of the Paris Agreement

In the development of the sintering of Ni-Ti alloys, it was noted the importance of carrying out an analysis regarding the influence of compaction load factors, temperatures and sintering times on their properties, given that these alloys are raw materials for biomedical products, such as implants and prostheses that need to have a high quality standard. The present study exposes the reasons why some samples showed more porosity than others, especially it is important to highlight that such samples with more porosity had a considerable decrease in hardness and mechanical resistance. The sintering temperature adopted was 1118°C, for periods of 12h and 24h, using analytical argon 2.0, taking into account the necessary care due to the high reactivity of titanium with other chemical elements. However, it was investigated why the samples that stayed in the oven for 24 hours had more pores compared to those that lasted 12 hours. Furthermore, it was observed that the greater the load applied, the greater the compaction of the alloy and the lower the porosity after sintering. The compression loads used were 21t and 30t, showing considerable differences in the final result of the specimens.

This paper shows many types of taxes and incentives for export and import from Brazil.
These issues are shown in the paper and proves that by using the right of these taxes all of buyer and seller can have good benefits for their products and company.

The linear production model in force since the Industrial Revolution has contributed significantly to environmental degradation and climate change. This production model is based on the linearity of extraction, production and waste disposal. The steel industry is responsible for a significant part of greenhouse gas emissions – GHG [1] and for the deterioration of the environment. This article proposes a model aimed at mitigating the impacts caused by the steel industry. Biomass residue from agriculture has stood out as a renewable energy source and a promising alternative for the sector. Thus, sugarcane bagasse, green corn straw and soy residue appear as important tools for mitigating impacts in this sector. This article proposes to develop an analysis of three distinct productions in the steel industry, namely: the production of steel via Blast Furnace [2], fueled energetically by the biomass of sugarcane bagasse; the production of coke, fueled energetically by soybean residue [3] and the reprocessing of steel through the Electric Arc Furnace (FEA) [4] fueled energetically by the biomass of green corn straw. The research findings suggest that the use of biomass as a renewable energy source and the reprocessing of steel through the FEA contribute significantly to the reduction of greenhouse gas emissions in the atmosphere, in addition to promoting the optimization of the use of resources and the reduction of stress environmental. Collaboration between the industrial and agricultural sectors is crucial for the proliferation of the use of biomass waste, also promoting the proper disposal of waste and generating economic and environmental benefits.

Gas carburizing of solid steel is carried out by using a large amount of hydrocarbon in order to keep the furnace atmosphere as long as constant, because carbon from hydrocarbon is consumed for carburization of the steel surface and hydrogen remains in the furnace. In the present study, selective removal methods of H2 were surveyed and fundamental experiment was done by using Proton Conductor SrZr1-xYxO3-a , which was prepared by spark plasma sintering method; hydrogen gas was separated from wet simulated coke oven gas atmosphere at high temperature successfully. At the same time, reported method to selectively remove H2 was also applied to bench scale furnace for gas carburizing of solid steel by using gas filter module made of poli-imido fiber tube. The control of the furnace atmosphere was very important to keep it constant, which was also studied numerically as well as experimentally. Finally, selective removal of H2 from the furnace was verified experimentally and the flow rate of so-called “carrier gas” (hydrocarbons) could be reduced more than 75 % under the condition of the same quality of steel surface by the carburization treatment. As a result, exhaust gas volume could also be reduced and the burnt exhaust gas, namely, CO2 emission was minimized.

This work consists of a study of the application of different types of biomass in the steelmaking process, these are the biomasses: Macaúba, soy, corn, elephant grass, sugarcane bagasse and coffee husks, considering that Steelmaking is responsible for 5% of emissions of greenhouse gases (CH4 and CO2). There is an attempt to replace part of the coal in the steelmaking process with biomass, but it is not possible to eliminate it completely because carbon is important in the reduction stage of Blast Furnaces, in addition, biomass needs to undergo processes and treatments that give it the desired characteristics. Biomass is all organic matter used to produce energy, which can be added to coke or injected into blast furnaces. Brazil's biodiversity needs to be used by ours through the incorporation of agribusiness residues into the steel sector. But to improve the calorific potential and decrease the reactivity of the biomass, additives can be added, as well as tar, which act by reducing the porosity of the biomass. In addition, demineralization can be performed to remove the inorganic part of the biomass in order to decrease its reactivity. The pyrolysis of biomass consists of heating the organic material without the presence of oxygen, direct thermal decomposition occurring (500 to 900°C) because when the temperature increases, the volatiles are eliminated, leaving carbon. Torrefaction is carried out at lower temperatures than pyrolysis (around 300°C) and is a technique that reduces the costs of cogeneration power plant because the biomass in this process becomes friable and easy to handle, but the torrefaction problem is that it does not concentrate the fixed carbon content.

Steelmaking is impossible without ferroalloys; up to 95% of ferroalloys is used in steelmaking, and growth of production of ferroalloys is driven by growth of steelmaking, which is expected to reach 2,500 Mt by 2050. Currently, more than 50 projects are in progress to decrease carbon emission in steelmaking. In comparison with ironmaking, which has more than a dozen different technologies, ferroallomaking is very conservative; it is based on the carbothermal reduction of oxides in submerged electric arc furnaces at high temperatures. The paper considers reduction of manganese oxides by hydrogen to MnO and carbothermal reduction of manganese, chromium and titanium oxides in hydrogen. MnO can be processed further to metallic manganese in the electrolytic process. Direct reduction of stable metal oxides (manganese, chromium, titanium, silicon and other oxides) to the metallic state requires very high H₂ to H₂O ratio, which can be achieved by the carbothermal reduction in hydrogen. Carbothermal reduction in hydrogen can be implemented at lower temperatures in the solid state with potential advantages over conventional reduction of oxides from molten slags.

This paper shows the study of the utilization of tire as fuel to be employed into blast furnaces. This tire can substitute coal or even charcoal in the blast furnaces tuyeres. The injection into tuyeres, other than contribute for energy generation, can produce gas for metallic oxide reduction, the former charged into the blast furnace throat, thus contribution for using other forms of wastes.

The tire, as powder, when to be injected into blast furnaces, contributes for an environmental employee of that waste, so as permit for obtaining a high value product. Then, one advantage of using such material is that it is waste and has lower cost for preparation.

A comparative study of combustion index of pulverized tires and coals was studied. For this study are been utilized one physical model, with thermal gradient constructed at Escola de Minas-UFOP. 

The results obtained have showed that the tires have good combustibility, this was obtained in a model that simulate the same conditions occurring in the blast furnaces tuyeres; these results include tires and mixtures of tires with coal or even with charcoal.

In order to verify the effect of ultrasonic waves to control the invasion of the golden mussel, Limnoperna fortunei, three experiments were made with different numbers of individuals and for each experiment the sonicator device was using at 40kHz frequency. In addition, the tests varied in time and days of exposure of the mussels to ultrasonic waves. As a result, several numbers for mortality and decoupling of the analyzed samples were noted, with significant differences regarding the exposure time per experiment and days in which the samples were submitted. Thus, the use of ultrasound to descale and kill the golden mussels was efficient and may be an alternative to control the invasion of L. Fortunei in to hydroelectric.

Industries have been directing their efforts towards improving their production processes, looking for new levels of environmental excellence. After the Paris Agreement set a framework for worldwide developments aimed at mitigating emissions and achieving a positive balance between anthropogenic emission sources, decarbonization has become a global objective. In this context, the use of by-products from other production processes has become essential for industries aiming to implement circular economy principles and contribute to the achievement of ESG goals.

In the search for sustainable and innovative ways to generate value for the production of iron ore pellets and for the society hosting its industrial complex, Samarco has identified opportunities to study raw materials obtained from residue generated in the mining of ornamental stones. Samarco’s pelletizing plants are located in a region with the highest production of iron ore pellets in the West and the fifth largest production of ornamental stones in the world. Because of that, its location is ideal for the implementation of circular economy practices by developing sustainable pelletizing raw materials from the high volume of waste generated in the extraction of granite and marble.

Samarco is the global pioneer in the use of marble mining residue as an input for pellet production due to the chemical and grindability similarity between marble and the calcitic limestone in the region. After laboratory and industrial-scale tests with excellent physical, chemical, and metallurgical results, results showed that the marble waste from the region has high CaO content, reducing the specific consumption by 16% in comparison to calcitic limestone, to meet the required physicochemical conditions for iron ore fired pellets. This results in a CO_2eq- reduction of 6.84 kg per ton of pellets, contributing to decarbonization in pelletizing, in addition to increasing the iron content of the fired pellets by 0.5%. Approximately 800 tons of marble mining waste removed daily from the environment are used as a fluxing agent and basicity corrector in iron ore pellets destined for blast furnaces and direct reduction reactors around the world.

Another sustainable raw material for use in iron ore pellets intended for direct reduction reactors is obtained from the cutting of granite stones. This input works as a coating agent, acting as a physical barrier capable of mitigating the tendency of pellets to stick together during reduction at high temperatures (between 950 and 1050 °C). The residue from granite cutting has ideal chemical characteristics and particle size to serve as a coating on pellets, remaining adhered to the surface of the agglomerates even during handling and until their use in the steel industry.

In addition to raw materials produced from residue in the mining of ornamental stones, Samarco has been innovatively seeking to diversify the energy matrix of its industrial complex through the increased use of renewable energies, specifically carbonized biomass, as an alternative to fossil fuels such as coal and coke.

The carbonization, handling, and fragmentation of charcoal for the supply of independent and integrated pig iron and ferroalloy production plants generate fine carbonaceous residues (charcoal fines), which do not achieve the granulometric specifications for reuse in other metallurgical processes. This material is discarded into the environment without prior treatment, which can have environmental, economic, and social impacts. In this context, studies have shown an opportunity for the recovery and reuse of these fines due to their considerable energy potential.

The use of these materials in processes such as pelletizing is considered carbon-neutral since the capture of CO₂ occurs during the growth and development of the trees planted to produce the charcoal through the process of photosynthesis. This amount of CO₂ is sufficient to compensate what is released during the production (carbonization) and combustion of the charcoal. Substituting the solid fuel matrix for the pelletizing plant in 50% of charcoal can reduce up to 22 kgCO_2eq- per ton of pellets. This represents nearly 190.000 tons per year of CO₂ removed from the atmosphere.

The higher friability of charcoal is advantageous for processes like pelletizing. Being a friable material facilitates grinding the fuel, making it easier to achieve the required particle size for sintering and pelletizing. Samarco conducted laboratory tests incorporating charcoal fines into pellet production to increase the diversification of its energy matrix with new renewable fuels. Both charcoal and charcoal fines were successfully tested on an industrial scale in 2023.

This article aims to explore technical aspects related to improving the quality of iron ore pellets and its decarbonization through the use of sustainable by-products in their production.

Brazil is one of the largest steel producers in the world, occupying the ninth position in the world ranking, with 1.8% of all world production (WORLD STEEL ASSOCIATION, 2022). The Brazilian production of crude steel in the year 2022 consumed around 34.1 million tons, 23.75% of which was produced using the electric melt shop method (INSTITUTO AÇO BRASIL, 2022). The increasing production of steel results in an increase in waste generation, since slag and PAE have fundamental functions in the steel manufacturing process, in order to guarantee good quality to the final product. These two by-products were considered of little or no value to the industry, and with the increase in production and the need for possible alternatives, adding value to these residues became necessary for the development of new markets. Electric melt shop dust (EAP) is generated during electric arc furnace (EAF) operation as a by-product of steel making. The high temperature used in the process for melting and refining the raw material (~1600°C) causes volatile elements, such as zinc, to volatilize and subsequently oxidize inside the furnace, producing metallic oxides in the form of particulate matter. Non-volatile elements, slag and additives, can be ejected from the liquid/gas interface by exploding carbon monoxide bubbles. Then, these can be oxidized and dragged by the gases generated in the process, being collected as dust in the dedusting system, normally through bag filters. Under such conditions, the various metal oxides can combine to form different compounds. As a result of these factors, the EAP undergoes a series of physical and chemical phenomena by which substances that give rise to the EAF powder are considered (PICKLES; MARZOUGHI, 2018; HOSSEINI et al., 2016).