酸化鉄ペレットの還元時における粒子内温度

Abstract

Intraparticle temperatures of the porous iron-oxide pellets having about 30% porosities during the gaseous reduction were measured by a thermocouple embedded into the center of the sample and the reduction rates of the similar samples were observed by a thermo-gravimetric method. Those intraparticle temperatures reflected that the reduction of iron-oxide was a multi-stage successive reaction and the variations of the temperatures with the progress of reduction corresponded to the reaction rates and heats of each reduction step.To predict theoretically such a temperature variation, the rate equations of the chemical reaction and the heat transfer were developed on the basis of the multi-interface unreacted core model. The calculated variations of the temperature by these equations adopting appropriate rate parameters coincided fairly well with the experimental results.Further, the errors of the rate parameters by ignoring the heat transfer resistances in the analysis of the experimental data of reduction were discussed from the theoretical calculation for the single step reduction. The exact values regarding the chemical reaction rate constant can be obtained but the considerable deviations may arise about the intraparticle effective diffusivity.