クロマイトの炭素還元における律速過程

抄録

Synthetic FeCr₂O₄ and MgCr₂O₄ were reduced by graphite powder under various conditions of temperature and gaseous atmosphere. The kinetic data were analyzed by the use of the rate equation offered by E. T. TURKDOGAN et al. for the oxidation of carbon with gaseous CO-CO₂ mixture.
In the carbothermic reduction of FeCr₂O₄, the rate was clarified to be mainly controlled by the BOUDOUARD reaction process, which was accelerated to a great extent by the metallic and carbide phases formed. On the other hand, the reduction rate of MgCr₂O₄ appeared to be mixed-controlled by the BOUDOUARD reaction and gaseous reduction processes.
Furthermore, the rate-determining process in the carbothermic reduction of more complicated chromites and chromite ores was examined on the basis of the rate constants for the carbothermic reduction of FeCr₂O₄ and Cr₂O₃. As the result, it was clarified that the reduction rate of those chromites, especially of Al₂O₃-containing chromites is mainly controlled by the gaseous reduction process of the chromite particle.