Aluminium recycling requires 95% less energy than primary production with no loss of quality. The Black Dross (BD) produced during secondary aluminium production contains high amounts of water-soluble compounds, therefore it is considered as a toxic waste. In the present work, salt removal from BD by thermal treatment has been investigated in laboratory scale. The optimum conditions for treatment were established, i.e., temperature, gas flow rate, holding time, rotation rate, and sample size. The overall degree of chloride removal was established to increase as a function of time and temperature. Even Pretreated Black Dross (PBD) was evaluated as a possible raw material for the production of a calcium aluminate-based ladle-fluxing agent to be used in the steel industry. The effects of different process parameters on the properties of the produced flux were experimentally investigated, i.e. CaO/Al2O3 ratio, temperature, holding time, and cooling media. The utilization of PBD as the alumina source during the production of a calcium aluminate fluxing agent shows promising results. The iron/steel industry is responsible for 9% of anthropogenic energy and process CO2 emissions. It is believed that the only way to a long-term reduction of the CO2 emissions from the iron/steel industry is commercialization of alternative processes such as Direct Reduction (DR) of iron oxide. Detailed knowledge of the kinetics of the reduction reactions is, however, a prerequisite for the design and optimization of the DR process. To obtain a better understanding of the reduction kinetics, a model was developed step-by-step, from a single pellet to a fixed bed with many pellets. The equations were solved using the commercial software COMSOL Multiphysics®. The final model considers the reaction rate and mass transfer inside the pellet, as well as the mass transfers and heat transfer in the fixed bed. All the models were verified against experimental results, and where found to describe the results in a satisfying way. / <p>QC 20161128</p>

O ferro-esponja ou DRI (Direct Reduced Iron) é obtido pelo processo de redução direta onde o minério de ferro é transformado em ferro metálico através de reações químicas envolvendo o estado sólido (minério) e o gasoso (gases redutores). Neste processo o minério de ferro não passa pelo estado líquido como ocorre com o ferro-gusa. Isto confere ao ferro-esponja algumas desvantagens que prejudicam o seu desempenho nas aciarias. Pode-se citar a redução no rendimento metálico e o maior consumo de energia elétrica como principais impactos de sua utilização intensiva. O ferro-esponja apresenta menor quantidade de ferro total (maior quantidade de impurezas) do que o ferro-gusa e também apresenta óxidos de ferro remanescentes em sua estrutura (menor metalização). Para torná-lo mais competitivo, inúmeras melhorias no processo têm sido promovidas para aumento da metalização. No entanto, o limite superior alcançado na prática tem ficado ao redor de 95%. Visando contribuir para melhorar a qualidade do ferro-esponja este trabalho apresenta uma proposta inovadora a partir da técnica de auto-redução. O objetivo é aumentar o grau de metalização do ferro-esponja através de seu aquecimento. Para isso, foram realizadas análises termogravimetrias e aquecimentos em forno mufla; análises químicas por via úmida, difração de raios-x, espectroscopia mössbauer e análise de microssonda de raios-x. As análises estruturais foram realizadas utilizando microscópio eletrônico de varredura para confirmar a efetividade da técnica apresentada. Nesta dissertação pode-se comprovar que, através da técnica de auto-redução, o ferro-esponja alcança metalizações acima de 98% em detrimento da queda do teor de carbono total. Um aumento de 4% na metalização traz um ganho estimado de 5 a 10% no consumo de energia elétrica nos fornos de fusão e um acréscimo proporcional na produção horária das aciarias. / The direct reduced iron is obtained by direct reduction process, where iron ore is transformed in metallic iron via chemical reactions involving solid (ore) and gaseous (reductant gases) states. In this process the iron ore does not pass by liquid state like pig iron. This become to direct reduced iron some disadvantages, which decrease its performance in the steelmaking process. It can be mentioned the reduction of metallic yield and the higher consumption of electric energy as the main impacts of its intensive use. The direct reduced iron presents lower amount of total iron (higher amount of impurities) than pig iron and presents iron oxides remained in its structure (lower metallization). To become more competitive, several improvements in the reduction process have been carried out to increase its metallization. However, the highest level of metallization, which has been reached, is 95%. To improve the direct reduced iron quality, the present work evaluates, in an innovative way, using the technique of self reduction. The objective is increase of metallization of the direct reduced iron through its heating. Thermal, chemical and structural characterization was carried out to check the effectiveness of the investigated technique. The research confirms that the direct reduced iron can reach a metallization higher than 98% with a decrease of total carbon amount using the technique presented in this work. An improvement of 4% in the metallization brings savings of 5 to 10% in the electric energy consumption of the electric arc furnaces and a proportional increase of the production in the steelmaking plants.

O ferro-esponja ou DRI (Direct Reduced Iron) é obtido pelo processo de redução direta onde o minério de ferro é transformado em ferro metálico através de reações químicas envolvendo o estado sólido (minério) e o gasoso (gases redutores). Neste processo o minério de ferro não passa pelo estado líquido como ocorre com o ferro-gusa. Isto confere ao ferro-esponja algumas desvantagens que prejudicam o seu desempenho nas aciarias. Pode-se citar a redução no rendimento metálico e o maior consumo de energia elétrica como principais impactos de sua utilização intensiva. O ferro-esponja apresenta menor quantidade de ferro total (maior quantidade de impurezas) do que o ferro-gusa e também apresenta óxidos de ferro remanescentes em sua estrutura (menor metalização). Para torná-lo mais competitivo, inúmeras melhorias no processo têm sido promovidas para aumento da metalização. No entanto, o limite superior alcançado na prática tem ficado ao redor de 95%. Visando contribuir para melhorar a qualidade do ferro-esponja este trabalho apresenta uma proposta inovadora a partir da técnica de auto-redução. O objetivo é aumentar o grau de metalização do ferro-esponja através de seu aquecimento. Para isso, foram realizadas análises termogravimetrias e aquecimentos em forno mufla; análises químicas por via úmida, difração de raios-x, espectroscopia mössbauer e análise de microssonda de raios-x. As análises estruturais foram realizadas utilizando microscópio eletrônico de varredura para confirmar a efetividade da técnica apresentada. Nesta dissertação pode-se comprovar que, através da técnica de auto-redução, o ferro-esponja alcança metalizações acima de 98% em detrimento da queda do teor de carbono total. Um aumento de 4% na metalização traz um ganho estimado de 5 a 10% no consumo de energia elétrica nos fornos de fusão e um acréscimo proporcional na produção horária das aciarias. / The direct reduced iron is obtained by direct reduction process, where iron ore is transformed in metallic iron via chemical reactions involving solid (ore) and gaseous (reductant gases) states. In this process the iron ore does not pass by liquid state like pig iron. This become to direct reduced iron some disadvantages, which decrease its performance in the steelmaking process. It can be mentioned the reduction of metallic yield and the higher consumption of electric energy as the main impacts of its intensive use. The direct reduced iron presents lower amount of total iron (higher amount of impurities) than pig iron and presents iron oxides remained in its structure (lower metallization). To become more competitive, several improvements in the reduction process have been carried out to increase its metallization. However, the highest level of metallization, which has been reached, is 95%. To improve the direct reduced iron quality, the present work evaluates, in an innovative way, using the technique of self reduction. The objective is increase of metallization of the direct reduced iron through its heating. Thermal, chemical and structural characterization was carried out to check the effectiveness of the investigated technique. The research confirms that the direct reduced iron can reach a metallization higher than 98% with a decrease of total carbon amount using the technique presented in this work. An improvement of 4% in the metallization brings savings of 5 to 10% in the electric energy consumption of the electric arc furnaces and a proportional increase of the production in the steelmaking plants.

O ferro-esponja ou DRI (Direct Reduced Iron) é obtido pelo processo de redução direta onde o minério de ferro é transformado em ferro metálico através de reações químicas envolvendo o estado sólido (minério) e o gasoso (gases redutores). Neste processo o minério de ferro não passa pelo estado líquido como ocorre com o ferro-gusa. Isto confere ao ferro-esponja algumas desvantagens que prejudicam o seu desempenho nas aciarias. Pode-se citar a redução no rendimento metálico e o maior consumo de energia elétrica como principais impactos de sua utilização intensiva. O ferro-esponja apresenta menor quantidade de ferro total (maior quantidade de impurezas) do que o ferro-gusa e também apresenta óxidos de ferro remanescentes em sua estrutura (menor metalização). Para torná-lo mais competitivo, inúmeras melhorias no processo têm sido promovidas para aumento da metalização. No entanto, o limite superior alcançado na prática tem ficado ao redor de 95%. Visando contribuir para melhorar a qualidade do ferro-esponja este trabalho apresenta uma proposta inovadora a partir da técnica de auto-redução. O objetivo é aumentar o grau de metalização do ferro-esponja através de seu aquecimento. Para isso, foram realizadas análises termogravimetrias e aquecimentos em forno mufla; análises químicas por via úmida, difração de raios-x, espectroscopia mössbauer e análise de microssonda de raios-x. As análises estruturais foram realizadas utilizando microscópio eletrônico de varredura para confirmar a efetividade da técnica apresentada. Nesta dissertação pode-se comprovar que, através da técnica de auto-redução, o ferro-esponja alcança metalizações acima de 98% em detrimento da queda do teor de carbono total. Um aumento de 4% na metalização traz um ganho estimado de 5 a 10% no consumo de energia elétrica nos fornos de fusão e um acréscimo proporcional na produção horária das aciarias. / The direct reduced iron is obtained by direct reduction process, where iron ore is transformed in metallic iron via chemical reactions involving solid (ore) and gaseous (reductant gases) states. In this process the iron ore does not pass by liquid state like pig iron. This become to direct reduced iron some disadvantages, which decrease its performance in the steelmaking process. It can be mentioned the reduction of metallic yield and the higher consumption of electric energy as the main impacts of its intensive use. The direct reduced iron presents lower amount of total iron (higher amount of impurities) than pig iron and presents iron oxides remained in its structure (lower metallization). To become more competitive, several improvements in the reduction process have been carried out to increase its metallization. However, the highest level of metallization, which has been reached, is 95%. To improve the direct reduced iron quality, the present work evaluates, in an innovative way, using the technique of self reduction. The objective is increase of metallization of the direct reduced iron through its heating. Thermal, chemical and structural characterization was carried out to check the effectiveness of the investigated technique. The research confirms that the direct reduced iron can reach a metallization higher than 98% with a decrease of total carbon amount using the technique presented in this work. An improvement of 4% in the metallization brings savings of 5 to 10% in the electric energy consumption of the electric arc furnaces and a proportional increase of the production in the steelmaking plants.

[pt] Nos últimos anos, esforços vêm sendo empreendidos no sentido de aumentar o conteúdo de carbono no ferro-esponja, com o intuito de utilizá-lo como fonte energética e como agente redutor dos óxidos residuais na operação dos fornos elétricos a arco - FEA. O presente trabalho, fruto de um projeto cooperativo da Samarco Mineração SA com o Grupo de Siderurgia da PUC-Rio, apresenta os resultados de experimentos realizados, nos laboratórios de ambas as Instituições simulando as condições operacionais de um forno Midrex. Para a simulação o reator foi dividido em três zonas: Redução, Transição e Resfriamento. Para cada uma delas foi concebido um conjunto de experimentos, estatisticamente planejados, de forma a permitir a mensuração cinética da carburização. Os experimentos envolvendo a redução e a carburização das pelotas de minério de ferro utilizaram similaridades fluidodinâmicas das escalas. Adicionalmente, um método para análise química dos teores de carbono grafítico e livre foi empregado com sucesso. Em seguida foram realizados os testes de carburização das zonas de transição e resfriamento e levantadas as curvas e equações cinéticas. Na zona de transição o agente carburizante foi o gás metano sendo a sua injeção feita nas temperaturas de 300, 600, 700 e 850 graus Celsius . O modelo cinético utilizado foi uma equação linear de fluxo mássico. O valor da energia de ativação aparente encontrada para a carburização do DRI na zona de transição foi de 12,31 kJ/mol indicando um controle cinético difusional. A carburização do DRI para esta região situou-se na faixa de 0.1 por cento C (300 graus Celsius ) a 3 por cento C (850 graus Celsius ) , para um tempo de residência típico de 0,7 horas. Na zona de resfriamento o principal agente carburizante depende da temperatura: acima de 400 graus Celsius , foi o gás metano, enquanto nas temperaturas abaixo de 500oC foi o gás CO. Nesta zona a carburização do DRI, nas temperaturas de 250 a 600 graus Celsius , foi suposta ser uma reação de primeira ordem em relação ao carbono. O resultado obtido para a energia de ativação aparente na zona de resfriamento foi 5,31 kJ/mol, consistente com um mecanismo controlado por difusão. Considerando os resultados experimentais obtidos, a carburização final do DRI nesta zona, tomando-se um tempo médio de residência de (2,15h) esteve na faixa de 2,0 por cento C ( periferia / 600 graus Celsius ) a 3,0por cento C ( centro / 250 graus Celsius ). / [en] In later years efforts are being made aiming at the increase in the carbon content in the DRI, this to enable it to act as energy source and reducing agent for the residual oxides in the operation of the electric arc furnaces – EAFs. The present work, product of a cooperative project between the Samarco Mining Co. and the Iron and Steelmaking Group from the University PUC-Rio, presents the obtained results for the experiments on DRI carburization, made at the laboratories of both institutions, under simulated conditions occurring in MIDREX reactors. To mimic the reactor operation, it was divided in three zones, quoting: Reduction, Transition and Cooling. For each of these zones a set of experiments were conceived and statistically planned to permit the carburization kinetic determination. It must be also added that fluidynamic scale similarity were respected in those same experiments. Further, a special chemical method was successfully employed to access the graphitic and free carbon DRI contents for the carburization tests performed for the Transition and Cooling zones. Based on the obtained results, sets of curves for carburization versus time were composed and kinetic equations, for various temperatures and gaseous atmospheres, were proposed. For the Transition zone the carburizing agent was the methane gas, being its injection made under the temperatures of 300, 600, 700 e 850oC. The kinetic model utilized for the carburization in this zone was that of a mass flux linear equation. From this formalism, an apparent activation energy of 12.3 kJ/mol was calculated indicating a difusional control. The total DRI carburization in this zone ranged from 0.1 per cent C (300oC) to 3 per cent C (850oC) for a typical residence time of 0.7 hours. In the Cooling Zone there was a temperature dependency ruling the carburizing agent role, above 400oC the gas methane is the main carburizing gas, but below 500oC the CO act as such. In this zone, the DRI carburization was fitted with a kinetic equation of the first order with respect to carbon. The obtained result for the apparent activation energy for this equation rated 5.31 kJ/mol, consistent with a difusional mechanism. Considering the experimental results for a residence time of 2.15 hours, the final carburization for the DRI in the Cooling Zone ranged from 2.0 per centC ( furnace peripheral conditions / 600oC ) to 3.0 per cent C ( core conditions / 250oC ).

Iron and its products, especially the various forms of steel, have been and still are a vital material in many sectors of life. It is utilized in many industrial activities ranging from production of heavy duty mechanical equipment to light electrical appliances and home appliances. With the world‟s iron ore consumption estimated to stand at 1.3 billion tonnes by 2025, exploitation of any existing natural deposits is of increasing importance to meet the demands of the expanding world economy. Large deposits of iron ore exist in Uganda in the eastern (Tororo) regions and south-western (Kisoro-Kabale) regions of the country. The ore deposits of Kisoro-Kabale consist of an iron-rich hematite grade with less deleterious impurities as compared to that of Tororo. Prospective quantification puts the deposits at 30-50 million tonnes of raw-ore reserves. To date the deposits lay unexploited, with small holder black smith activities taking place in the area. This work involves understanding the occurrence, quantity and quality of the ore plus its properties and characteristics in a bid to pave way for its exploitation for economic use in Uganda and beyond. Characterisation was done on the samples collected from the deposits, to establish its physical, chemical and metallurgical properties. Literature detailing the natural occurrence of the deposits plus the genesis of the parent rocks and ore and the prospective tonnage is included. The economic situation in Uganda as far as demand and consumption of iron and steel is concerned is also briefly highlighted. The chemical, physical and metallurgical characteristics that could facilitate the initial exploitation of the ore are examined with conclusive results from the representative samples examined. The results present Muko ore as a high grade of hematite with an Fe content averaging 68%. The gangue content (SiO 2+Al2O3) of 5 of the 6 samples investigated is &lt; 4%, which is within the tolerable limits for the dominant iron production processes, with its S and P contents being &lt; 0.1% and 0.07% respectively. Thus, Muko iron ore can be reduced in the furnace without presenting major difficulties. With respect to mechanical properties, Muko ore was found to have a Tumble Index value &gt; 85 wt%, an Abrasion Index value &lt; 4 wt% and a Shatter Index value &lt; 2.5 wt%. This implies that the ore holds its form during the processes of mining, transportation, screening and descent when loaded in the furnace for reduction. Its reducibility index was found to be 0.868%/min. This is well within the desired reduction limits for the major iron reduction processes. It implies that a high productivity (in terms of iron reduced) can be realised in the reduction processes in a given period of time. Muko iron ore was found to meet most of the feed raw material requirements (physical, chemical and metallurgical) for the blast furnace and the major direct reduction processes (Midrex, HYL III and SL/RN). Furthermore, for those desired for sinter and pellet making. It can thus serve well as a feed raw material for smelting reduction and direct reduction processes. / QC 20101007 / Sustainable Technological Development in the Lake Victoria Region

[pt] Pelo presente trabalho, buscou-se desenvolver uma ferramenta capaz de analisar e otimizar o uso de pelotas de minério de ferro em processos tradicionais de redução direta do tipo forno cuba. A criação de um modelo termoquímico do processo MIDREX foi proposta e elaborada dentro da PUC-Rio, levando-se também em conta alguns aspectos cinéticos relativos à redução dos minérios e à carburização do ferro-esponja, bem como alguns parâmetros operacionais. Este modelo foi subseqüentemente adaptado para interagir com um segundo modelo termoquímico de forno elétrico a arco da RS Consultants, representando assim a cadeia de fabricação de aço líquido primário pela rota redução direta - forno elétrico a arco. Para o gerenciamento computacional do processo de otimização e interação com os dois modelos acima citados, desenvolveu-se, adicionalmente, um terceiro modelo, o qual foi designado neste trabalho como modelo GESTOR. Um máximo uso de ferro-esponja ― e de pelotas, conseqüentemente ― é objetivado sempre que possível, sob determinadas condições operacionais pré-estabelecidas. A avaliação econômica destes processos foi embasada em conceitos de valor de uso. Alguns resultados são apresentados neste trabalho, para demonstrar a efetividade e o poder de análise da ferramenta e espera-se que os profissionais da Samarco possam fazer uso deste instrumento de trabalho, dando o devido suporte à tomada de decisão à comercialização e ao desenvolvimento de produtos existentes ou novos. / [en] The study at issue searched for developing an innovative tool able to effectively analyze and optimize the industrial usage of iron ore pellets undergoing traditional gas-based direct reduction processes. The creation of a thermochemical model for MIDREX process was proposed and carried out by PUC-Rio, taking into account relevant characteristics related to DRI carburization and reduction kinetics, as well as some important operating parameters. Subsequently, this model was adapted in order to interact with a second thermo-chemical model owned by RS Consultants and able to represent an electric arc furnace operation. In this sense, it has been possible to represent thereby the iron and steelmaking route based on direct reduction and electric arc furnace. For the computational management of the optimization methodology and interaction involving the two models above-mentioned, a third model was developed and referred to as GESTOR model. It was built to maximize the DRI usage ¯ and pellets utilization, consequently ¯ respecting certain operating conditions previously established. Economic assessments shall be made premised upon value in use concepts. Some results are shown in this study, based on a hypothetical scenario, aiming at proving the effectiveness of this tool. Its adoption by Samarco´s experts is expected as an important supportive methodology to help them to make decisions properly concerning both marketing strategies and product development activities.

Cherchant des voies de réduction drastique des émissions de CO2 d’origine sidérurgique (projet européen ULCOS), nous avons envisagé une réduction du minerai de fer par l’hydrogène pur dans un réacteur du type four à cuve. L’approche suivie a associé bibliographie, expérimentation et modélisation. Le déroulement de la réaction chimique et sa cinétique ont été analysés à partir d’expériences thermogravimétriques et de caractérisations physico-chimiques d’échantillons en cours de réduction. Un modèle cinétique spécifique a été mis au point, qui simule les réactions successives, les différentes étapes du transport de matière et le frittage éventuel du fer, à l’échelle d’une particule de solide. Enfin, un modèle numérique bidimensionnel du four à cuve a été écrit. Il décrit l’évolution des températures et des compositions des solides et des gaz en tous points d’un réacteur fonctionnant sous hydrogène. Une des originalités de ce modèle est l’utilisation de la loi des temps caractéristiques additifs pour exprimer les vitesses des réactions. Celle-ci permet de coupler les deux échelles que sont celles des particules et du réacteur, tout en gardant des temps de calculs raisonnables. A partir des simulations réalisées, l’influence des paramètres du procédé a été quantifiée. Des conditions opératoires optimales ont été dégagées, qui illustrent bien le potentiel du procédé / In an effort to find new ways to drastically reduce the CO2 emissions from the steel industry (ULCOS project), the reduction of iron ore by pure hydrogen in a shaft furnace was investigated. The work consisted of literature, experimental, and modelling studies. The chemical reaction and its kinetics were analysed on the basis of thermogravimetric experiments and physicochemical characterisations of partially reduced samples. A specific kinetic model was designed, which simulates the successive reactions, the different steps of mass transport, and possible iron sintering, at the particle scale. Finally, a 2-dimensional numerical model of a shaft furnace was developed. It depicts the variation of the solid and gas temperatures and compositions throughout the reactor. One original feature of the model is using the law of additive characteristic times for calculating the reaction rates. This allowed us to handle both the particle and the reactor scale, while keeping reasonable calculation time. From the simulation results, the influence of the process parameters was assessed. Optimal operating conditions were concluded, which reveal the efficiency of the hydrogen process

Ce travail de thèse est consacré à la modélisation du procédé de réduction directe du minerai de fer, un procédé alternatif intéressant dans le contexte de la réduction des émissions de CO2 de la sidérurgie. Le four à cuve, réacteur central du procédé, est divisé en trois zones (réduction, transition et refroidissement). Le modèle mathématique mis au point pour simuler l’ensemble repose sur une description détaillée et fidèle des principaux phénomènes physico-chimiques et thermiques intervenant. C’est un modèle bidimensionnel, en régime permanent et multi-échelle. Le lit mobile est constitué de boulettes, elles-mêmes supposées composées de grains et de cristallites. Huit réactions chimiques hétérogènes et deux réactions chimiques homogènes sont prises en compte. Les équations de conservation locales de la masse, l'énergie et de la quantité de mouvement ont été résolues numériquement en utilisant la méthode des volumes finis. Ce modèle a été appliqué avec succès pour simuler le four à cuve de deux usines de réduction directe de capacités différentes. Les résultats obtenus renseignent sur le fonctionnement interne du four et mettent en évidence des zones aux performances inégales. Le modèle a ensuite été exploité, après l’ajout et le couplage d’un modèle du reformeur, pour des calculs paramétriques, en particulier lorsque les caractéristiques des gaz réducteurs sont modifiées. Enfin des pistes sont présentées pour optimiser une installation de réduction directe en augmentant la capacité de production et le degré de métallisation du produit / This thesis is dedicated to the modelling of the iron ore direct reduction process, an attractive alternative process for making steel in the context of the reduction in CO2 emissions. The shaft furnace, the core reactor of the process, is divided into three sections (reduction, transition and cooling). The mathematical model developed to simulate this reactor is based on a detailed and faithful description of the main physical-chemical and thermal phenomena involved. The model is a two-dimensional, steady state and multi-scale. The moving bed is comprised of pellets of grains and crystallites. Eight heterogeneous chemical reactions and two homogeneous chemical reactions were taken into account. The local mass, energy and momentum balances were solved numerically using the finite volume method. The model was successfully applied to simulate the shaft furnace of two direct reduction plants of different capacities. The results obtained provide new insights on the internal behaviour of the furnace and highlight zones of uneven performance. After the addition and coupling of a reformer model, the shaft furnace model was used for parametric calculations, in particular when considering changes in the composition of the reducing gases. Finally, new possibilities are presented for optimizing the direct reduction process, e.g. for increasing the production capacity and the degree of metallization of the produced iron

[pt] A produção e o uso de DRI (Direct Reduction Iron) são cada vez maiores hoje em dia nos países desenvolvidos, essencialmente pela redução do preço do gás natural e do sucesso da tecnologia de extração de gás de xisto. Além disso, o menor teor de elementos contaminantes em DRI do que nas sucatas de aço, levou-o a ser considerado uma boa alternativa como carga metálica para o Forno Elétrico a Arco (FEA) e o processo no conversor LD /BOF. Os custos operacionais e os problemas ambientais, são atualmente dois fatores tecnológicos importantes a serem considerados na otimização da produção de DRI, afetando à produtividade, sustentabilidade e competitividade do processo industrial. O teor de carbono do DRI, por exemplo, tem se tornado cada vez mais importante, devido à sua capacidade de gerar energia química nas aciarias, complementando o uso de energia elétrica nos FEA e os inputs energéticos no LD. Este trabalho foi uma das partes do programa de cooperação entre a Companhia de Mineração Samarco e o Grupo de Siderurgia da Pontifícia Universidade Católica do Rio de Janeiro / PUC-Rio, que tratou especificamente do modelo cinético para a metalização e carburização simultâneas em fornos RD tipo cuba. No âmbito deste objetivo o reator foi dividido em três zonas: Redução, Transição e Resfriamento. Foram também consideradas mais três camadas concêntricas: periférica, media e central. Com base nos resultados obtidos em experiências que abrangeram diferentes tipos de pelotas, empregando misturas gasosas semelhantes às presentes nos processos industriais e obedecendo às suas correspondentes semelhanças fluidodinâmicas, foi desenvolvido um software, denominado METCARB, que incluiu na sua elaboração todas as equações e modelos cinéticos desenvolvidos experimentalmente nas três zonas do reator RD. A parte experimental foi, portanto, uma das partes principais do presente trabalho, conjuntamente com a concepção do modelo computacional e suas validações industriais. Com o METCARB, as previsões acerca da metalização e carburização simultâneas, em qualquer região interna do forno, se tornou possível, utilizando como entradas as dimensões do forno, medidas de temperaturas, composições dos gases, etc. Os resultados de metalização e carburização, também em formato gráfico, são gerados pelo sistema computacional, bem como as curvas cronométricas e tabelas de resultados. Estudos sobre dois casos reais foram realizados, a fim de validarem a ferramenta computacional desenvolvida. Constatou-se que a carburização do ferro metálico sempre ocorre simultaneamente com a redução dos óxidos de ferro e que, dependendo da temperatura e composição dos gases, pode ocorrer precipitação de finos de carbono. As simulações realizadas com o modelo METCARB mostraram que na periferia da ZR é gerado um DRI mais metalizado que na região do centro. Fenômeno contrário foi, entretanto, verificado com a carburização; Nas condições experimentais empregadas neste trabalho, os valores médios obtidos para a carburização e a metalização, no final da ZR, variam entre 0,4 - 0,7 por cento C, e 92 por cento - 97 por cento, respectivamente; Constatou-se não ocorrer progresso do grau de redução nas zonas de Transição (ZT) e de Arrefecimento (ZA), ou seja, mantiveram-se ao longo dessas zonas os valores de metalização obtidos no fundo da ZR; A influência do vapor de água no processo da carburização no caso estudado (0 - 4.25 por cento H2O) leva menor porcentagem de carburização (2,7 por cento C – 2,35). / [en] The production and the use of DRI (Direct Reduction Iron) are increasing today in developed countries, mainly by reducing the price of natural gas and the success of shale gas extraction technology. In addition, the lower level of contaminants in DRI than in metal scraps, led it to be considered a good alternative as metallic charge for the Electric Arc Furnace (EAF) and the process in LD / BOF converter. This work was one part of the cooperation program between Samarco Mining Company and Steel Group of the Pontifical Catholic University of Rio de Janeiro / PUC-Rio, which specifically dealt with the kinetic model for the metallization and carburization simultaneous in RD shaft furnaces. Under this purpose the reactor was divided into three zones: Reduction, Transition and Cooling. There were also three concentric regions considered: peripheral, media and center. Based on the results from experiments covering different types of pellets, using gas mixtures similar to those present in the industrial processes and obeying their corresponding fluid dynamic similarities, it developed a software called METCARB, which included in its preparation all kinetic equations and models developed experimentally in the three reactor zones of RD. The experimental part was therefore a major part of this work, together with the design of computational model and its industrial validations. With METCARB predictions about the simultaneous metallization and carburization in any internal region of the furnaces, it became possible, using as inputs the dimensions of the furnace, temperature measurements, compositions of gases, etc. The results of metallization and carburization also in graphic format are generated by the computer system, and the chronometric curves and results tables. Studies on two real cases were performed in order to validate the developed computational tool. It was found that the carburization always occurs simultaneously with the reduction of iron oxides and, depending on the temperature and composition of the gases; precipitation of fine carbon may occur. The simulations with METCARB model showed that the periphery of the ZR generated more DRI metallized than the center area. A contrary phenomenon has been verified with the carburization; With the experimental conditions used in this study, averages values obtained for the metallization and carburization in the final ZR vary between 0.4 - 0.7 percent C and 92 percent - 97 percent, respectively; It was not found that the progress of reduction degree occurred in the transition (ZT) and cooling (ZA) regions, in other words, it remained along these zones of the metallization values obtained at the bottom of ZR; The influence of water vapor in the carburization process in the case studies (0 - 4.25 percent H 2 O) takes a smaller percentage of carburization (2.7 percent C - 2.35).