Multistep Kinetics Study on Hydrogen Reduction of 0.25–0.5 mm Iron Oxide Particles

In this paper, the influence factors on the reduction degree of iron oxide were studied through a direct hydrogen reduction thermogravimetric experiment. The results show that the inlet flow rate and temperature both promote the improvement of the reduction degree, and the higher the inlet flow rate and temperature, the shorter the time required for iron oxide to reach the maximum reduction degree. The entire reduction process of iron oxide can be divided into three stages: the Fe2O3 → Fe3O4 stage, Fe3O4 → FeO stage and FeO → Fe stage. The control mechanism of each stage is based on interfacial chemical reaction, second-order chemical reaction and interfacial chemical reaction, respectively, and the linear fitting degree is good. The final activation energy values of the three stages are 39.696 kJ/mol, 28.129 kJ/mol and 19.110 kJ/mol, respectively.