Effective Use of CH4 Gas as a Reducing Agent in Suspension Reduction Process

Abstract

The current study investigated the reduction and carburization in the suspension reduction of the fine Chinese Benxi magnetite ore with CH4-containing gas. A very high fractional reduction was achieved by CH4-containing gas at 1 300 degrees C compared with that by H-2 or CO gas. The reduction rate of the ore by CH4 was higher than that by H-2 above 1150 degrees C. The activation energies of the ore reduction by 11 vol%CH4 and 20 vol%H-2 were calculated to be 113.6 and 76.9 kJ/mol, respectively. The reduction mechanism analysis showed that the formation of thin Fe layer reduced from wustite and the carbon dissolved into metallic shell by carburization had great influences on the further reduction progress. It is believed that the subsequent progress is related to the formation of less dense shell of metallic Fe with some cracks by the building up of gas pressure at Fe/wustite interface. Furthermore, the synergistic effect of H-2 addition to CH4 gas on the reduction of the magnetite ore was also clarified.