真空低价氟化铝歧化分解制备铝

Preparation of aluminum by disproportion of sub-fluoride in vacuum

利用“物质吉布斯自由焓函数法”，讨论不同压力下低价氟化铝生成及分解的热力学条件。结果表明：系统压力为100kPa时，在1941．76K以上才能生成低价氟化铝；而当系统压力降低到100～10Pa时，在1486．32～1373．28K能生成低价氟化铝。同时，当系统压力小于300Pa时在1673K下用氧化铝、氟化铝与还原剂碳在真空炉内实验，验证了理论研究结果，得到纯度为93．77％的金属铝；以焦碳作还原剂，铝土矿为原料在1723K进行了实验，得到纯度为95．13％的金属铝。

Thermodynamics process and experiment of aluminum extracting from bauxite and Al2O3, were studied. The temperature, at which alumina, aluminum fluoride and carbon react to form aluminum sub-fluoride at different pressures, was evaluated with ＂Substance Gibbs＇ Free Energy Functional Determinant＂ method. The results show that the reaction temperature can be considerable declined in vacuum, such as the temperature dropped to 1 486.32-1 373.28 K in the pressure range from 100 Pa to 10 Pa, but the temperature of the reaction needed is more than 1 941.76 K under 100 kPa. The metal aluminum with the purity of 93.77% is obtained by the experiment alumina, aluminum fluoride and carbon in a vacuum furnace when the system pressure is less than 300 Pa at 1 673K; the aluminum metal with the purity of 95.13% is also gotten at 1 723 K by using coke for reducing bauxite.