Reduction of Wustite Pellets with H₂-CO-CO₂ and H₂-CO₂ Gas Mixtures

Abstract

The applicability of the reduction model proposed in the previous paper (Tetsu-to-Hagané, 73 (1987), p. 972), in which the water-gas shift reaction and multi-component gas diffusion were taken into account, to the reduction kinetics of wustite pellets with H₂-CO-CO₂ and H₂-CO₂ gas mixtures was examined. The gas composition was such that the reduction was possible to take place not with CO-CO₂ but only with H₂. In the calculation, the parameters included in the model were modified depending on the gas composition by using the method proposed in the previous paper.
The following results were obtained;
1) The reduction curves calculated by the model agreed well with the observed data except the case of lower H₂ concentration.
2) The effect of the water-gas shift reaction was not so significant on the reduction curves, but it was remarkable on the mass transfer rate of each component of gas mixture.
3) Depending on the reduction condition, especially at higher H₂ concentration, CO/CO₂ ratio in the pellet increased because of the water-gas shift reaction. As a result, the reduction of wustite with CO took place instead of the oxidation of reduced iron with CO₂.