(1. 北京科技大学 物理化学系, 北京 100083;
2. 中国科学院 化工冶金研究所,北京 100080)
摘 要: 在测定MnO2碳热还原表观活化能的基础上, 确认MnO2碳热还原可以分为三个阶段: 1) 在 f <0.3时, 其控制环节为气相扩散, 2) 当0.3< f <0.6时, 其控制环节为碳气化反应, 3) 当 f >0.6时, 其控制环节为固相扩散。 稀土氧化物(La2O3, CeO2和Ce2O3)对MnO2碳热还原有催化作用,并以La2O3效果最佳。 催化的机理在于对碳气化反应的催化。
关键字: MnO2碳热还原;稀土氧化物; 催化作用
(1. Department of PhysicoChemistry, University of Science and Technology Beijing, Beijing 100083, P.R.China;
2. Institute of Chemical Metallurgy, Chinese Academy of Sciences, Beijing 100080, P.R.China)
Abstract:Based on reduction experiment, it is concluded that the carbonthemic reduction of MnO2 is distinctly divided into three stages: gas diffusion controlling stage, carbon gasification controlling stage and solid diffusion controlling stage. The effect of rare earth oxide (La2O3, CeO2 and Ce2O3) on carbothermic reduction of MnO2 was then investigated and it was found that the rare earth oxides have catalytic effect on reduction and La2O3 is the most affective.SEM analysis discloses that the catalytic mechanism is that rare earth oxide catalyzes the carbongasification reaction.
Key words: MnO2 carbothermic reduction; rare earth oxide; catalysis