真空下碳热还原氧化铝的热力学

Thermodynamics of carbothermal reduction of alumina in vacuum

对真空条件下碳热还原氧化铝进行热力学研究。结果表明:在1 643～1 843 K的温度范围内,真空碳热还原氧化铝生成气体产物,该气体在温度降低时发生二次反应形成冷凝物,反应过程中体系压力保持在5～150 Pa。热力学分析表明:当体系压力为1～100 Pa时,在1 200～1 900 K的温度范围内,碳热还原氧化铝生成Al2O、Al和CO;生成Al2O的初始反应温度低于生成Al的初始反应温度,但反应温度高于一定值时,更易生成Al气体,该温度取决于体系的压力;当CO的分压分别为1、10和100 Pa时,Al2O稳定存在的温度分别高于1 462、1 560和1 674 K,Al气体稳定存在的温度分别高于1 514、1 635和1 777 K。

The thermodynamics of the carbothermal reduction of alumina in the vacuum was investigated.The experimental results show that the reduction of alumina with carbon generates gaseous products at a temperature ranging from 1 643 to 1 843 K,and then the gaseous products react to form condensates at lower temperatures,in which the pressure is ranged from 5 to 150 Pa.Thermodynamic analysis indicates that the carbothermal reduction of alumina leads to the generation of Al2O,Al and CO gas at a temperature ranging from 1 200 to 1 900 K and a pressure ranging from 5 to 100 Pa.The initial temperature of the formation of Al2O is lower than that of the formation of Al.However,the formation of Al is easier than that of Al2O when the reaction temperature is higher than a certain value that is determined by the pressure of the system.When the pressure of CO is 1,10 and 100 Pa,Al2O is stable above 1 462,1 560 and 1 674 K,and Al is stable above 1 514,1 635 and 1 777 K,respectively.