Kinetics of Carbothermic Reduction of MnO₂ and Catalytic Effect of La₂O₃

Kinetics of carbothermic reduction of manganese oxide and the catalyticeffect of La₂O₃ on the reduction have been studied by the measurement of mass loss in N₂ atmosphere at different temperatures and followed by SEM analysis. It is concluded that the kinetics of carbothermic reduction of manganese oxide is divided into three stages:gas diffusion controlling stage, carbon gasification con-trolling stage and solid state diffusion controlling stage. La₂O₃ has catalytic effect on the reduction. The catalytic effect of La₂O₃ increases withthe added amount of La₂O₃. SEM analysis shows that the catalytic mechanism is that La₂O₃promotes the transfer of oxygen ions so that carbon gasifying is catalyzed and thus carbothermic reduction of MnO₂ is catalyzed.