真空铁热还原氧化锂制备金属锂的热力学分析与实验初探

Preliminary Study of Iron Reduction of Lithium from Lithium Oxide in Vacuum

通过相关的热力学理论计算，对常压及真空条件下以碳酸锂为原料分解成氧化锂以及铁热还原氧化锂制备金属Li进行了热力学分析，计算结果表明：常压下碳酸锂很难发生分解反应，当系统压力降到1Pa时，碳酸锂的临界分解温度降为889K，并且真空中用铁还原氧化锂制备金属Li是可行的。并根据计算设计进行了铁还原氧化锂实验，实验结果表明：在热力计算上，系统压强为1～5Pa，温度为1423-1573K的条件下，金属铁能还原出金属锂，锂的还原率为48％以上。

We addressed the feasibility of lithium extraction from lithium oxide, decomposed of lithium carbonate, in vacuum. First, the decomposition of lithium carbonate and iron reduction of lithium oxide, in vacuum and in atmospheric pressure, respectively, were theoretically calculated on the basis of thermodynamics. The calculated results show that lithi- um carbonate, impossible to break up in atmospheric pressure, can be decomposed at 1 Pa and a critical temperature of 889 K, and that it is feasible to reduce lithium oxide with iron in vacuum. Next, the lithium oxide was experimentally re- duced in vacuum with iron powder as the reduction agent. The tested results show that under optimized conditions： at a pressure ranging from 1 to 5 Pa, and a temperature from 1423 to 1573 K, it is feasible to extract metallic lithium from lithium oxide at a reduction rate over 48 %. Finally, possible improvement of the technique was tentatively discussed.