Reduction Rate of Iron-Oxide Pellets Under Heating Series

Abstract

Based on the fact that gas diffusibility (D_e/D_H2-H₂O) of reduced iron depends on its reduction temperatures remarkably, a mathematical model of diffusion rate through shell layer of reduced iron under heating series was presented.
This model was examined by reduction experiments which were carried out in isothermal conditions and heating series using ferric oxide pellet. By analyzing the rates of isothermal reduction by the unreacted core model, parameters of chemical reaction constant k_r and intraparticle diffusivity D_e were estimated as functions of reduction temperature.
The reduction rates under heating series were calculated by using a model in which the above parameters were substituted. Those calculated results agreed well with the experimental results.