真空下碳热还原氧化铝的二次反应

Back-reactions of carbothermal reduction of alumina in vacuum

通过热力学分析和实验研究了真空条件下碳热还原氧化铝的二次反应。热力学分析表明:低温、高压有利于碳热还原氧化铝的产物Al2O、Al与CO的二次反应。分别绘制了Al2O和Al在一定分压下,与CO的二次反应平衡曲线图,给出了各二次反应的CO平衡分压与温度的关系,根据CO的分压和温度、利用二次反应平衡曲线图分析二次反应的产物。氧化铝与石墨的真空碳热还原实验研究证实:Al2O与CO降低温度首先生成Al4O4C和C,Al与CO降低温度首先生成Al4O4C和Al4C3,符合根据二次反应平衡曲线图分析得到的结论,说明二次反应平衡曲线图的合理性。

The back-reactions of the carbothermal reduction of alumina in a vacuum were investigated. The thermodynamic analysis indicates that both low temperature and high pressure favor the back-reactions of A1203, A1 and CO generated from the carbothermal reduction of alumina. The equilibrium curves for the back-reactions of A12O and CO, and those of A1 and CO are obtained, respectively, for certain partial pressures of A12O and those of A1, showing the CO equilibrium partial pressure of the back-reactions as a function of the temperature. From the equilibrium curves, the species formed by the back-reactions are determined by the CO partial pressure and the temperature. The experiments on the alumina and graphite show that AI2O reacts back with CO to first form A1404C and C, and A1 reacts back with CO to first form A14OgCand A14C3, verifying the conclusions obtained from the equilibrium curves. The equilibrium curves of the back-reactions are reasonable.