Analysis on Reductive Kinetics of SSI Reduced by Hydrogen
Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology, reductive kinetics of SSI was analyzed on the basement of unreacted core model. In the light of the single reaction surface theory, the ratio of internal diffusion resistance fI and chemical reaction resistance fR was calculated according to the weight loss curve of SSI reduction. Under different temperature, both fI and fR increased with the reaction time, especially the radium of unreacted core was small after a period of reaction time. Compared the ratio of fI and fR, it concluded that SSI reduced by hydrogen was controlled by the chemical reaction, combination of chemical reaction and the internal diffusion, the internal diffusion under the temperature being lower than T3, from T3 to T4, more than T5, respectively.