Title

KINETIC OF DRI CARBURIZATION IN SHAFT FURNACES

KINETIC OF DRI CARBURIZATION IN SHAFT FURNACES

Authorship

D’Abreu, José Carlos; Otaviano, Mauricio Marcos; Kohler., Hélio Marques

D’Abreu, José Carlos

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Otaviano, Mauricio Marcos

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Kohler., Hélio Marques

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DOI

10.5151/2594-357X-22438

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Abstract

Nowadays the Direct Reduction processes are one of the most important ironmaking routes. Over the past few years, technological efforts have been made to increase the carbon content in the sponge iron (DRI), aiming its use as an additional energy source and as a reducing agent for the residual oxides in EAF operations. To deepen the understanding of the DRI carburization phenomena in the direct reduction processes, Samarco Company and the Catholic University of Rio de Janeiro (PUC-Rio) established a plentiful cooperative program concerning this subject. With this objective the shaft reactor was firstly divided into three segments: Reduction, Transition and Cooling zones. For each of these zones a set of experiments were designed in order to obtain the kinetic DRI carburization parameters and, as a consequence, to determine the proper conditions needed to achieve the allowable carbon contents in the DRI. The experimental methodology, encompassing pellet reduction and carburization, reproduced gaseous mixtures similar to those present in the industrial process, obeying the correspondent fluid dynamic similarities. Due to the importance to know the carbon content in the DRI matrix a specific chemical analytical method was applied to distinguish carbon as graphite and cementite phases. Finally, parameters, equations and graphics were obtained and set up, encompassing the referred three shaft reactor zones.

Nowadays the Direct Reduction processes are one of the most important ironmaking routes. Over the past few years, technological efforts have been made to increase the carbon content in the sponge iron (DRI), aiming its use as an additional energy source and as a reducing agent for the residual oxides in EAF operations. To deepen the understanding of the DRI carburization phenomena in the direct reduction processes, Samarco Company and the Catholic University of Rio de Janeiro (PUC-Rio) established a plentiful cooperative program concerning this subject. With this objective the shaft reactor was firstly divided into three segments: Reduction, Transition and Cooling zones. For each of these zones a set of experiments were designed in order to obtain the kinetic DRI carburization parameters and, as a consequence, to determine the proper conditions needed to achieve the allowable carbon contents in the DRI. The experimental methodology, encompassing pellet reduction and carburization, reproduced gaseous mixtures similar to those present in the industrial process, obeying the correspondent fluid dynamic similarities. Due to the importance to know the carbon content in the DRI matrix a specific chemical analytical method was applied to distinguish carbon as graphite and cementite phases. Finally, parameters, equations and graphics were obtained and set up, encompassing the referred three shaft reactor zones.

Keywords

Direct reduction; Kinetic Modeling; DRI; Carburization.

Direct reduction; Kinetic Modeling; DRI; Carburization.