Reduction Characteristics of Pure Gale Limonite Pellets in Gaseous Environments

抄録

In this study, the isothermal reduction mechanism of limonite, an important iron ore resource, in H₂, CO, and a mixed atmosphere of both gases was studied as a function of reduction temperature and gas composition. The kinetics of the reduction process were studied using a shrinking kernel model. The experimental results show that the degree of reduction of the oxidized pellet particles increases with increases in both reduction time and temperature. Also, it has been found that an increase in the ratio of H₂/(H₂ + CO) and an increase in temperature result in shortened reduction times. During the reduction process, the kinetic studies show that the early stage of the gas reduction process is controlled by the interfacial chemical reaction and later stages are controlled by diffusion. SEM results show that the particles reduced in the H₂ atmosphere have many micropores. Providing a gas passage during the reduction process reduces the gas diffusion resistance and promotes the diffusion reaction.

Fig. 5 Reduction degree curves of oxidized pellets at 973 K∼1373 K with (a) CO and (b) H₂.