CONTRIBUIÇÃO AO ESTUDO DA CINÉTICA DE REDUÇÃO DE BRIQUETES AUTO-REDUTORES / THE REDUCTION KINETICS KINETICS OF SELF-REDUCING BRIQUETTES

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

The present work, analyzes the impact of the key variables, temperature, reduction atmosphere and composition of the ferrous and carbonaceous materials, on the kinetics of self- reducing briquettes, for two types of samples, over the temperature range 1000 - 1300°C. A brief history of the ironmaking science is presented, covering the most relevant features of the main self-reduction processes and a survey of the main published researches on the same subject relating to thermodynamic and kinetic aspects. The experimental procedure, details of the apparatus used, the experimental parameters, characterization of the samples and the results are described. Based on the results obtained, the kinetic parameters were evaluated determining the apparent activation energy (E0) as 177,10 kJ/mol and the pre-exponential frequency factor of the Arrehnius equation (ê0) as 0,97x10-3 s-1. It is observed that, increasing the temperature, decreasing the inert gas flow (N2) and using CO atmosphere, improves significantly the kinetics of reduction of self-reducing briquettes, raising the rate of iron oxide reduction. The results confirm that the Boudouard reaction is the rate limiting step of the overall reaction, up to 1200°C, when a mixed control starts, where the influence of the iron oxides reduction shall be also considered. The significance of this experimental results and observations to the design and the development of an innovative self-reduction smelting process are highlighted.

ASSUNTO(S)

briquettes self-reducing briquetes cinetica kinetics activation energy boudouard auto-reducao energia de ativacao boudouard

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