Abstract
Chromium ore pellets containing carbonaceous material were reduced at various temperatures between 950 and 1350°C in the flowing atmospheres of H2-CO with different H2 concentrations. The rate of reduction increases to a large extent with the increase in H2 concentration. In 100% H2 atmosphere it is much higher than that in any other atmosphere investigated up to date. The kinetic analysis on the basis of a simplified reaction model showed that such promotion of reduction with H2 is mainly due to the decrease in resistance of intraparticle diffusion of gaseous reactants and products through the reduced layer formed around chromite grain. The desulphurization during reduction of the pellet is remarkably promoted by the presence of a relatively low concentration of H2 in furnace atmosphere. It seems that organic sulphur originated from coke is removed in the earlier stage of reduction and at lower temperatures whereas the sulphur removal from inorganic sulphide requires higher temperatures.
