Leite International Symposium (10th Intl. Symp. on Advanced Sustainable Iron & Steel Making)

The steelmaking industry is of fundamental importance in the energy context of Brazil, being characterized as one of the major consumers of electricity in the country. To be competitive in the global market, the steelmaking industry needs to show an excellent strategic plan. This plan includes efficient energy planning, seeking to make better use of resources, low environmental impacts and operating costs [1]. The thermoelectric power plants of coke integrated steelmaking industry demonstrate great economic potential, since they make use of the waste gases from the process [2]. The aim of this work is to analyze, from the environomic viewpoint, the thermoelectric power plant, observing the influence of hydrogen addition. The generation of hydrogen is by water electrolysis, driven by photovoltaic power. The methodology comprises of using a computational model created with Scilab [3]. For model validation, the actual data from the thermal power plant is used. Thermoeconomic modeling aims to obtain a system of cost equations that mathematically represents the cost formation process in the plant [4]. The computer simulations use seven scenarios of possible fuel mixtures, using the BFG, LDG, COG, and H2. The results indicate that up to 30% of hydrogen with BFG is possible to obtain energy and exergy efficiency equivalent to scenario zero that most represents the operation of the thermoelectric plant and still reduce the fuel cost [5]. The importance of energy management in an organization is highlighted in terms of potential financial gains and cost reductions. Scenario 0 based the real operating model showed lower exergetic efficiency 23.87%.

Although the denomination “steelmaking” is much more  common in English, the world “siderurgy”  also exists in English. The name “siderurgy” comes from the old Greek world for iron: sideros. Steelmaking and Ironmaking revolutionized the history of humankind: There are distincts quality of life for the 4 main hystorical ages: stone age, copper age [1], bronze age, and iron age. 

Nowadays it became clear that the Old Egyptians were less advanced in metallurgy - or ironmaking - than their neighbors: The Tut-ankh-amon dagger is  meteoritic (due to high nickel) and, besides, it probably was imported from Mittani or Hittite lands [2], thats is, present day Turkey .

The transition of bronze to iron and steel was very important for quality of life: In the iron age, furniture could be easily  manufactured, and also ships and boats. This revolutionized the commerce. Bronze was very expensive due to the scarce and essential alloying element  tin (11-12% in bronze). Instead, iron ore can be found almost everywhere.

It is reviewed the complex process that gave origin to smelting [3,4], for steel and iron production:  Magnetite maybe the first ore used for reduction. The origin of first smelting techniques are still uncertain [5]. More and more it became clear that Black Sea regions started the iron smelting process, possibly in areas related to the Chalybes [6], near present day Trebzon.

The present study investigates the advantages and feasibility of the shaft furnace in direct reduction processes, highlighting its energy efficiency and flexibility in the choice of reducing agents. The complexity of the processes involved within the furnace is addressed, dividing it into four distinct zones. Although mathematical models have been developed to predict direct reduction, their application is limited due to the simplification required in the face of the complexity of the phenomena. The integration of the shaft furnace with partial replacement of the charge by self-reducing pellets is explored, demonstrating a potential increase in process efficiency and reduction in CO₂ emissions. This study proposes a multiphase and multicomponent mathematical model to predict the internal temperature distribution of the furnace, validated by simulations on an industrial scale. The results indicate a significant increase in productivity and metalization when using self-reducing pellets, as well as, a reduction in carbon emissions when partially replacing conventional reducing gas with hydrogen. The findings highlight the importance of optimizing operational parameters to maximize the benefits of the shaft furnace in direct iron production.

The development of effective technological methods for controlling non-metallic inclusions is a promising direction for improving the complex of properties and quality characteristics of steels. One of the factors regulating the quantity, morphology and distribution of sulfide inclusions over the metal volume is the sulfur content. To organize the production of steel with low sulfur content (up to 0.003 - 0.005%), the desulfurization process is carried out in ladle-furnace installations with the formation of the main slags of the CaO-SiO2-Al2O3 system and deep deoxidation of steel with aluminum. At the same time, one of the main oxide inclusions in steel deoxidized with aluminum is corundum (Al2O3), which deteriorates the properties of steel and leads to “overgrowth” of the inner surface of the immersion nozzle during continuous casting. This negative effect of corundum in steel can be neutralized by removing it into the main liquid slag formed in the ladle-furnace by reducing the activity of Al2O3. However, in practice, an excessive increase in the basicity of refining slag to reduce the activity of Al2O3 is usually accompanied by heterogenization of the slag, an increase in its melting temperature and a decrease in refining properties. One of the promising directions for reducing the activity coefficient of Al2O3 in basic refining slags may be the use of rare earth metal oxides. The use of REM oxides ensures a decrease in their melting point, an increase in fluid mobility, an increase in the coefficient of interphase distribution of sulfur and a decrease in the coefficient of interphase distribution of REM. The paper presents the results of a study of the influence of cerium oxide in the slags of the CaO-SiO2-Al2O3-MgO-CeO2 system on the physicochemical properties. New data were obtained on the influence of temperature, cerium oxide and the basicity of the formed slags on the equilibrium interphase distribution of cerium. 

The research was supported by a grant from the Russian Science Foundation.

The production of Tyre cord grades requires not only a very good surface quality in the wire rods but also a very high degree of steel cleanliness. The reason is that the application is safety critical and the end use in Tyre demands a very high level of cleanliness.

There is both fine drawing and also patenting involved in the manufacturing process which means that both gas content and the inclusion content need to be extremely low. Achieving lower gas content as well as inclusion levels is a challenge in the tyre cord manufacturing process. Careful inclusion engineering, selective use of synthetic slags, high process reduction ratios in rolling and use of rectangular bloom sections are all critical to Tyre cord manufacturing. This paper discussed all the critical parameters that need to be controlled in the manufacturing of Tyre Cord steel.

Since essentially the Tyre Cord is a high carbon steel, all precautions that are necessary to avoid segregation like low superheat, optimum casting speed, and optimum rolling & soaking parameters as to be maintained. Since Al₂O₃ inclusions have to be as low as possible, the selection of the right synthetic slag and Sulphur control while tapping are key to the success of manufacturing these grades. In case sulfur is not low (<0.01%) in tapping, then external heat metal desulfurization is a must before refining.

India is poised to emerge as a global hub in car manufacturing, which will be requiring huge quantities of Tyre cord steels for the local usage of Tyre. This presents a unique opportunity for Indian special steel makers to not only be part of the global supply chain but also to significantly reduce the carbon footprint of steel by eliminating the emissions in the transportation of steel from Abroad.

This project discusses the potential of producing Tyre cord steel in India and the opportunity to reduce the carbon footprint by manufacturing near to local Markets.

With the green hydrogen starting at 4.45  US$/kg, [1] hydrogen usage seems difficult. Not only the green hydrogen is very expensive, even the gray hydrogen is uneconomical. However, hydrogen production is a possibility when there is oversupply of electric energy.

In California, renewables as solar and wind already able to provide almost 100% of the energy, avoiding fossil fuels as coal and natural gas [2]. Both windy days or sunny days offer the possibility of in-excess production of energy [2], which can be employed for cheap hydrogen production.

Usually, DRI – Direct Reduction of Iron – request high quality iron ore [3], offering a possibility for Brazil in this market. Vale is considering a hub for HBI (hot briquetted iron) in Porto do Açu in Brazil [4]. Other possible hubs are planned for Saudi Arabia, Oman and Dubai, due to the possibility of cheap natural gas [5].

This study addresses economic issues of hydrogen usage in steelmaking.

This study investigates the potential of combined injection of hydrogen as fuel and pulverized charcoal (PCH) in the operation of blast furnaces, aiming to reduce carbon emissions and increase energy efficiency. Through a detailed computational model, we analyzed various operational scenarios with different rates of PCH and hydrogen injection. The results demonstrate that the partial or total replacement of pulverized coal (PC) with PCH can significantly increase blast furnace productivity, reducing coke consumption and carbon emissions. An improvement in internal material distribution and temperature was also observed, with an acceleration in burden descent and a modification in the temperature pattern in the raceway region. Furthermore, it was found that progressive increases in PCH and hydrogen injection can lead to substantial increases in blast furnace productivity, with additional reductions in coke consumption and carbon emissions. These results highlight the potential of combined hydrogen and PCH injection as a viable strategy to promote sustainability and efficiency in the steel industry, aligned with decarbonization and circular economy objectives.

The steel industry is responsible for 5% of total energy consumption and contributes 6% of CO₂ emissions worldwide [1]. Brazil produces around 30% of the world's charcoal and a large part of this is used to produce pig iron, ferroalloys and silicon metal. There is a large proportion of artisanal production in the country and pressure for sustainable production systems has led to the development of new clean technologies with higher yields [2]. There are a total of 21 types of carbonization furnaces, of which there are 172 patents with various improvements to the carbonization process [3].

Residues from rice, maize, soy, wheat and other crops such as bambo have high energy potential, and these sources can contribute to increasing electricity generation [4]. The carbonization process has evolved, as has furnace productivity, and making full use of the energy contained in biomass has reached technological limits [5]. With finite natural resources and an industry that is intensive for the development of society, it is necessary to develop alternatives in the direction of the circular economy [6].

This article carries out an analysis of the availability of maize waste and bamboo biomass in Brazil, as well as a review of the optimized carbonization process, where there is use of the gases generated and co-products from the pyrolysis process. The article also evaluates a charcoal generation process that can be adapted to the conditions of biomass availability in the regions of Brazil.

According to the International Energy Agency (IEA) [1], the steel sector, among heavy industries, ranks first in CO2 emissions and second in energy consumption. Iron and steel are directly responsible for 2.6 gigatons of carbon dioxide (GT CO2) emissions annually, accounting for 7% of the total global energy system. The Sixth Assessment Report (AR6) of the IPCC (United Nations Intergovernmental Panel on Climate Change) of 2023 [2], containing a comprehensive study on the climate situation of the planet, has shown in a worrying way that the goals established on December 12, 2015, in the Paris Agreement, which aims to limit global warming to less than 2, preferably 1.5 degrees Celsius, are increasingly out of reach. Brazil is the largest steel producer in Latin America and the ninth largest in the world, according to the Instituto Aço Brasil [3]. Brazil's energy park has large renewable energy sources (hydroelectric, wind, solar and biomass plants), reaching 93.1% of electricity generation in 2023, E3G [4].In this way, with the decarbonization process of steel production, combined with the use of Biochar, green hydrogen, will make Brazil a major player in the production of green steel.This study aims to evaluate the ways and processes in which Brazil has been planning its decarbonization, thus contributing to achieving the goals of the Paris agreement.

According to the International Energy Agency (IEA) [1], the steel sector, among heavy industries, ranks first in CO2 emissions and second in energy consumption. Iron and steel are directly responsible for 2.6 gigatons of carbon dioxide (GT CO2) emissions annually, accounting for 7% of the total global energy system. The Sixth Assessment Report (AR6) of the IPCC (United Nations Intergovernmental Panel on Climate Change) of 2023 [2], containing a comprehensive study on the climate situation of the planet, has shown in a worrying way that the goals established on December 12, 2015, in the Paris Agreement, which aims to limit global warming to less than 2, preferably 1.5 degrees Celsius, are increasingly out of reach. Brazil is the largest steel producer in Latin America and the ninth largest in the world, according to the Instituto Aço Brasil [3]. Brazil's energy park has large renewable energy sources (hydroelectric, wind, solar and biomass plants), reaching 93.1% of electricity generation in 2023, E3G [4].In this way, with the decarbonization process of steel production, combined with the use of Biochar, green hydrogen, will make Brazil a major player in the production of green steel.This study aims to evaluate the ways and processes in which Brazil has been planning its decarbonization, thus contributing to achieving the goals of the Paris agreement.

The iron and steel industry contributes about 7 % of the total carbon dioxide emission globally and about 35% of all CO₂ produced in the manufacturing sector[1, 2]. About 1.9 tons of CO₂ is produced per ton of crude steel [3, 4]. Carbon from coke or coal is the primary source of heat energy in blast furnaces and rotary hearth furnaces used worldwide. Carbon in the form of graphite electrodes is also used in electric arc furnaces. Thus, it is easy to comprehend that carbon is used extensively in the entire steel making route, making it a high contributor to global CO₂ production. Using hydrogen gas as a reductant in place of carbonaceous material offers significant advantages like zero greenhouse gas (GHG) emissions, faster reduction at lower temperatures, and the absence of a complicated boudouard (C-O) reaction. Most hydrogen reduction studies have been carried out on commercial-grade iron ores containing more than 65% Fe, and limited studies are available on the hydrogen reduction of low-grade ores containing less than 50% Fe [3, 5]. 

The hydrogen reducibility of pellets made from a low-grade multimetallic magnetite ore (Fe content ~45%) was investigated in the present study. Pellets were reduced in a horizontal tube furnace at temperatures ranging from 973 K to 1173 K for 1 to 60 minutes. Pure Hydrogen (H₂) gas (99.9%) at three flow rates of 0.25 L/min, 0.5 L/min, and 1 L/min were blown during the reduction process. A maximum reduction degree of 93.55%, metallization ratio of 0.925, and H₂ gas utilization of 8.92% were obtained at a temperature and a reduction time of 1173 K and 60 minutes, respectively. In order to optimize the hydrogen utilization, a reduction temperature of 1173 K, a reduction time of 45 minutes, and a gas flow rate of 0.25 L/min were selected, resulting in a reduction degree and metallization ratio of 89% and 0.86, respectively. The cold crushing strength (CCS) of the reduced pellets initially decreased and then increased slightly, exhibiting behavior similar to high-grade ores. SiO₂, Al₂O₃, and MgO are found to control the porosity of the pellets, which directly affected the CCS and reducibility of the pellets.   

The main challenges in sintering technology in the iron and steel industry are improving productivity and ensuring quality of sintered ore. Uneven heat distribution and high emissions are major concerns. Another pressing issue is the high level emissions, with sintering & blast furnace processes accounting for 60% of emissions in the industry. Researchers have explored various approaches such as double ignition, changing gas compositions, recycling hot flue gases, using additional gaseous fuels and so on. Among these methods, varying the inlet gas conditions is considered a practical solution for better utilization of solid fuel without extensive plant retrofitting. The present study evaluates the impact of injecting oxygen during Iron ore sintering process on temperature profile and distribution, sintering time, yield, productivity, and other sintering process parameters. Lab scale trials were conducted using a pot sinter setup wherein, oxygen was injected from the top of the sinter bed at flow rates of 70 to 100 LPM for 5 to 15 minutes, keeping all the other parameters constant. There was a 30 to 40% increase in the holding time for sinter above 1200 ˚C, leading to the formation of a high-strength calciumferrite texture within the sinter. The sinter Tumbler Index (TI) was found to be increasing from 62.80 to 69.27%. The injection of oxygen also helped maintain the Burn through Temperature (BTT) above 450 ˚C. The mean particle size for the sinter increased from 18.5 mm to 21 mm. Thermography observations showed that the red hot region that indicates the movement of the flame front and temperatures above 1200 ˚C, expanded upward with oxygen injection.

Promoting the transition from the current linear production and consumption model to a green model has become a central issue in the debates on global warming and climate change. [1] [2]. The way we design and produce our products directly affects the types and intensities of impacts generated on the environment and, consequently, on the planet.[3]. However, with the aim of deliberately creating products with a shorter useful life than they could have and making consumers purchase new products in short intervals of time, obsolescence has been used by industries as a tool to increase consumption [4]. This problem is particularly noticeable in the smartphone production model. This article intends to carry out a qualitative and quantitative analysis of the current production and consumption model, proposing the analysis of the factors that influence the increase in smartphone consumption, highlighting both the determining factors and the hindering factors, it also intends to identify how such practices can violate several Brazilian laws [5]. To achieve this, the research developed a questionnaire via Google Forms, applied to 186 people. The results show that external motivators (such as marketing incentives and social stimuli), internal motivators (self-actualization), external impediments (economic barriers) and internal impediments (mental awareness barriers and perception of real need) were the four determining factors that influenced or prevented new consumption.

Among the priority tasks for the development of the country's metallurgical complex, the problem of improving the quality and reducing the cost of metal products remains relevant. Improving the quality characteristics of structural steels is carried out at all technological stages of steel production. The thermodynamics of the phosphorus oxidation reaction, macrokinetics of oxidation processes, phase composition, structure and physicochemical properties of multicomponent slags of the CaO-SiO2-FeO-MnO-P2O5-MgO and CaO-SiO2-B2O3-Al2O3 system, including viscosity, equilibrium interphase distribution of sulfur and boron during out-of-furnace processing of steel.

The results of fundamental research form the basis for the development of innovative technological solutions that provide:

- smelting of intermediate steel in oxygen converters and modern EAFs under magnesium slag of rational composition with a guaranteed low phosphorus content and high durability of the refractory lining of steel-smelting units;

-deep desulfurization and direct microalloying of structural steel grades with boron in ladle-furnace installations using environmentally friendly boron-containing slag.

The introduction of developed innovative technological solutions ensured the production of low-carbon boron-containing structural steels of a new generation, sparingly alloyed with manganese, with low phosphorus and sulfur content and a complex of increased mechanical properties, incl. for large-diameter pipes of strength category X80 without heat treatment with the prospect of reaching strength category X100-X120.

Catalytic Wet Peroxide Oxidation (CWPO) allows the removal of recalcitrant organic compounds under mild conditions when using hydrogen peroxide and a solid catalyst with redox properties to generate •OH from the H₂O₂ decomposition [1]. Clays modified with the mixed Al/Fe system have shown excellent performance in CWPO systems for the degradation of organic compounds (including contaminants of emerging concern) present in wastewater [2]. In this study, a series of pillared interlayered clays including aluminum, iron and cooper has been prepared. This work presents a comparative study of those solids on the phenol oxidation in diluted aqueous medium with hydrogen peroxide at 25°C and atmospheric pressure. 

Al, mixed Al-Fe and Al-Cu pillared clays have been prepared using the conventional method in a dilute medium with two parameters added to this synthesis. The first is the cooling of clay suspension and the second one is the exchange between clay and metal solutions before pillaring.

The dispersion of the cold clay suspension, before the pillaring, increases the basal spacing and the specific surface area. Mixed Al-Fe and Al-Cu pillared clays have comparable performances in very mild reaction conditions, although they showed some differences in the H₂O₂ decomposition kinetics. A total conversion of H₂O₂ is obtained without completely phenol conversion over mixed Al-Fe pillared clays suggesting the presence of the active species in these catalysts.

Iron exchanged and post-pillared clay with mixed (Al-Fe) solution containing 10% of iron expressed as molar percentage (Fe/MR-AlFe(10)) is the most efficient for this reaction combining good catalytic activity with high stability against iron leaching (0.02%). Its shows total phenol degradation, the highest H₂O₂ decomposition (85.7%) and more than 80% of TOC removal after 15h of reaction.

India is one of the 3^rd  largest steel producers in the world, Iron Ore Beneficiation & Pelletization plants along with DRI plants which will remain the backbone of Iron & Steel Industry in the world. Existing DRI plants were commissioned by employing processing techniques suitable for good quality Iron ore lumps / fines.

Present scenario some of them are utilizing   various types of process equipment and technologies i.e., rotary kiln, T.G. KILN, S.G. kiln, VSK, and Roller KILN Gate process methods. Through our innovative technology we don’t want to embrace machineries. The entire process can be carried out with the help of chemicals and, hence, sponge iron and steel industries can avoid huge investments in machinery. The chemical and physical properties of the green pellets are the same as that of the conventional method as they undergo the same conventional treatment. By graduating to this simple process, sponge iron and steel manufacturers can reduce capex by an impressive 35-40%. In the conventional method, green pellets are fired in the rotary kiln for which, over and above coal needed for injection, coal lumps, dolomite and limestone are fed. The author said, “Our innovation requires only injecting coal firing. Also, there is no need for separation after receiving the material from the kiln. We encourage the use of powder waste from mines so that production and fuel costs can be curtailed. Specific coal consumption comes down by 10% and as there is no accretion and no fused lump formation, the refractory repairing cost can be reduced by 50%. Also, maintenance, power and production costs can be reduced.”

Raghuvamsi Technologies is using only fines to produce 10 to 20 mm pellets in the rotary kiln. the green pellets keep calcined continuously at a desired rate. Once the mix is fed into the drum, heating by an external burner located near the ignition hood starts and suction of each pellet moving from feed to the discharging end is ensured. It is important that the amount of water used should not be either too little or too much. Insufficient moisture should not generate capillary that is required for bonding. Once nucleation starts, pellets start growing at an exponential rate. The ratio of water to chemical (whether powder or liquid) used is 10:1 and maintaining this ratio is crucial. For 1,000 liters of water, the amount of chemical to be used should not exceed 10.0 liters. These green pellets are then dried in normal temperature or kiln waste heat at 100-150 degree Celsius to produce pellets with acceptable strength.

The development of the steel industry in Brazil is a story of continuous growth and modernization, driven by investments in technology, expansion of production capacity and the search for new markets. However, this sector faces significant challenges in both import and export, which impact its competitiveness and sustainability. In recent decades, the industry has undergone a process of modernization, with investments in more efficient and sustainable technologies, such as the use of electric furnaces and the adoption of circular economy practices. Brazil has become one of the largest steel producers in the world, with an installed capacity of over 50 million tons per year. In addition, the steel industry is a major employer, providing thousands of direct and indirect jobs, and contributing significantly to the country's industrial GDP. In the areas of import and export, competitiveness with China and the United States is analyzed, as they impose trade barriers, as well as tariffs, aiming to protect their local industries. Steel prices are volatile due to the interference of factors such as global demand, material costs and trade policies. Furthermore, the steel industry is one of the largest contributors to CO2 emissions into the atmosphere, and the search for more sustainable production is leading the industry to invest in greener technologies.

This study points out the characteristics of Ti-6Al-4V alloys, that contains additions of 6% Al and 4% V by weight, and it also aims about the advantages of the laser weldingon these alloys compared to conventional methods of welding, because they usually cause problems such as oxidation of the faces joined by the weld, porosity and overheating of the joining metals. Occurs that Ti-6Al-4V alloys are widely used in aeronautical industry and in biomedical applications, due to its excellent properties, as well as mechanical strength, corrosion resistance, toughness and biocompatibility. But due to the high cost of these alloys, conventional welding cannot be done in order to avoid losses.The laser welding method, however, is appropriate due its accuracy, high penetration, high speed and easy handling. The main characteristics of this alloy that make it so special are: lightness, mechanical strength, biocompatibility, corrosion resistance, weldability and resistance to high temperatures. The addition of aluminum and vanadium significantly improves the strength of this alloy, remaining resistant even in corrosive or high-temperature environments. For this reason, they are widely chosen for use in biomedical and aerospace devices.

The Ni-Ti alloy exhibits exceptional properties that enhance its compatibility with the human body, notably its low density, mechanical strength, corrosion and wear resistance, shape memory effect, and superelasticity. The shape memory effect involves a thermal hysteresis due to phase transitions from martensite to austenite when the alloy is cooled and then heated above its transformation threshold, enabling it to revert to its original shape. The superelasticity effect allows the material to return to its original shape after deformation of up to 10% under applied load. In this study, three samples containing 49.5% Ti and 50.5% Ni were produced using the powder metallurgy technique. The chemical composition of these samples was analyzed. The Ni and Ti metal powder mixture was sintered in a controlled atmosphere furnace at 1118°C in the presence of an inert atmosphere with analytical argon 2.0. Following analysis under an optical microscope and scanning electron microscope (SEM), Vickers microhardness, corrosion, and wear tests were conducted to evaluate the alloy's suitability for prosthetics and orthopedic implants.

The discussion of sustainable development is directly related to the materials sector, in the first instance because materials are essential for socioeconomic development and in the second instance because of the environmental impacts related to the extraction and management of the sector. Everything from buildings and infrastructure to technology and consumer goods relies on materials. Environmental pressures push the industry and the commerce sector to adopt a more eco friendly stance. Companies are rethinking how they operate to be greener. They're looking for ways to use materials that are less harmful to the environment. This might mean using recycled materials or finding alternatives to traditional materials that are more sustainable. This matters because it helps us deal with big issues like pollution and climate change. As a result, the materials sector has been undergoing adjustments to accommodate the new reality. In this sense, the adoption of sustainable practices in the materials sector is a basic condition to combat the social, economic and environmental problems of present and future generations. In view of the theme presented, the work aims to analyze the evolution of materials over the years in the face of market pressures and the green economy. 

The present work aims to analyze the characteristics of macauba (Acrocomia aculeata), as well as its occurrence in Brazil and its energy properties that differentiate it from other biomasses due to its extreme importance for the generation of clean energy, from sources extracted from the environment and for sustainable development. The energy potential of macaúba biomass provides the strengthening of the Brazilian domestic market, since the oil extracted from this palm tree may have differentiated applications, including in industries. Compared to other biomasses, it is noted that macauba oil is produced in greater quantity and has high agricultural profitability. In the steel mill, the use of macaúba contributes to mitigate the emission of polluting gases resulting from the burning of fuels in blast-ovens, besides having several other advantages, as well as the low amount of ash generated. The use of biomass as a partial replacement for coal can significantly reduce CO2 emissions and other air pollutants associated with iron and steel production, thus contributing to reducing environmental impact. Another interesting aspect is that steel mills often use biomass as a renewable energy source to generate electricity and steam through cogeneration systems. This can reduce dependence on non-renewable energy sources and reduce operating costs. In addition to using biomass as an energy source, steel mills can also use organic waste to produce biofuels or to generate thermal energy. This contributes to reducing waste and to more sustainable management of natural resources. The use of biomass as a partial replacement for coal can significantly reduce CO2 emissions and other air pollutants associated with iron and steel production, thus contributing to reducing environmental impact. Another interesting aspect is that steel mills often use biomass as a renewable energy source to generate electricity and steam through cogeneration systems. This can reduce dependence on non-renewable energy sources and reduce operating costs. In addition to using biomass as an energy source, steel mills can also use organic waste to produce biofuels or to generate thermal energy. This contributes to reducing waste and to more sustainable management of natural resources.

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 numbersof 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 analyzedsamples were noted, with significant differences regarding the exposure time per experiment and days in which  the sampleswere submitted. Thus, the use of ultrasound to descale and kill the golden musselswas efficient and may be an alternative to control the invasion of L. fortunei.

In 1991, Limnoperna fortunei (Dunker, 1857), also known as the golden mussel, was found at the mouth of the Rio de la Plata and, since then, it has expanded rapidly, mainly along the Paraguay and Paraná rivers. Vessel traffic between Argentina and Brazil has become one of the main causes of golden mussel dispersal (DINIZ, 2010). This invasive species originates from Southeast Asia and has spread to South America through the ballast water of ships coming from China (RIBOLLI et al., 2021).

This bivalve mollusk has a great capacity for proliferation, which is due to its morphological characteristics, such as its shells and its sessile characteristic, in addition to its evolution shaped by the environment (PAULA et al. 2021). Thus, it is expected that invasive alien species without control of their proliferation become an environmental, social and economic problem in environments that are not originally their natural habitat (IBAMA, 2020).

The invasion of golden mussels, for example, generates numerous environmental consequences, compromising biomes, lakes, vegetation cover, water quality, among others. The release of organic material (pseudofeces) by these organisms affects the phytoplanktonic 

and zooplanktonic community, causing loss of habitat for some species of fish and other organisms (IBAMA, 2020).

With regard to technologies developed by man, hydroelectric plants are one of the main structures that suffer from the invasion of the golden mussel (PAULA et al., 2021). In addition, net cages are also significantly affected by golden mussel fouling (COSTA et al. 2012). When detecting the presence of larvae in ballast water from contaminated vessels, control strategies must be developed to avoid further contamination and intense propagation of the species, mitigating its impacts (SANTOS; WÜRDIG; MANSUR; 2005).

The first National Strategy on Invasive Exotic Species defined criteria for analysis and classification of species and, according to CONABIO Resolution nº 5, of October 21, 2009, the golden mussel can be categorized as an exotic and invasive species, since its Dispersion translates into social, economic and environmental risks. Therefore, it is important to develop strategies to mitigate and contain its dispersion and/or impact (MINISTÉRIO DO MEIO AMBIENTE, 2009).

Control methods with ultrasonic waves for golden mussels in hydroelectric power plants are still the subject and there is not a significant amount of related studies, however, their application has been shown to be significant (PEREIRA, 2012). The elaboration of analysis around this exotic species, exploring the ultrasonic techniques, shows promise in fulfilling the objectives of containment and control of the proliferation of L. fortunei, as well as, consequently, mitigating its implications in the environment, society and economy.

OBJECTIVES

General objectives

To verify the effect of ultrasonic waves on the control of golden mussels.

Specific objectives

 Carry out and publicize the ultrasonic technique for controlling the golden mussel;

 Understand, in the literature, how the invasions of Limnoperna fortunei affect industries and environments, and the possibilities of control;

 Evaluate the influence of ultrasonic waves on the control of golden mussels under different time intervals.

According to Almeida 

Despite bringing several consequences to industries with systems already infested by L. fortunei, given the research carried out in recent years, this problem can be solved, since many methods have become efficient in combating mussels, such as the use of sonicator devices.

This study was able to prove the effectiveness of ultrasound for the decoupling and death of golden mussels, which enables their control based on this physical treatment. Therefore, this study becomes extremely relevant, above all, given the need to reduce the economic and environmental impacts caused by the golden mussel which, as mentioned in this research, can range from the obstruction of pumps in hydroelectric plants to impacts on the quality of water and biomes, among other problems.

Finally, it is possible to carry out future research that explores other parameters for the experiments, such as the use of other ultrasound bath devices, as well as different exposure times. Other delimitations that may also contribute to this line of research can address how ultrasonic waves can be used in loco, in order to establish a control method in the place where incrustations cause damage to companies and other environments that need control, thus being able to bring advances to the solutions for controlling the golden mussel through ultrasonic waves.