铝电解废旧阴极酸浸液除氟回收锂工艺研究

铝电解废旧阴极经过硫酸浸出得到了含有Na、Li、Al、F等有价元素的浸出液，具有回收价值的同时伴随着严重的二次污染。采用冰晶石结晶法两次除氟，除氟后回收锂。实验结果表明：当反应pH=9、n(Al):n(F)=1∶6、反应温度为50℃、反应时间为90 min、晶种添加量为0.8 g/L时，溶液中残氟浓度为48 mg/L,一次除氟率为98.15%,锂除去率为1.38%;经过二次除氟后，溶液中氟的浓度为49 mg/L,二次除氟率为85.12%,锂除去率为2.13%;经过两次除氟后，氟总除去率为99.38%,锂总除去率为1.31%;制备出的Li₂CO₃纯度大于99.5%。

Research on the process of fluoride removal and recovery of lithium from aluminum electrolytic waste cathodic acid leaching solution

The aluminum electrolytic waste cathode was leached with sulfuric acid to obtain a leaching solution containing valuable elements such as Na, Li, Al, and F. The leaching solution has recovery value, but it is accompanied by serious secondary pollution. In this paper, the cryolite crystallization method is used to remove fluoride twice, and the lithium is recovered after fluoride removal. When the reaction pH=9, n(Al):n(F)=1:6, the reaction temperature was 50 °C, the reaction time was 90 min, and the crystal seed addition was 0.8 g/L. The residual fluorine concentration in the solution was 48 mg/L, the one-time fluoride removal rate was 98.15%, and the lithium removal rate was 1.38%. After the secondary fluoride removal, the concentration of fluorine in the solution was 49 mg/L, the secondary fluoride removal rate was 85.12%, and the lithium removal rate was 2.13%. After two fluoride removals, the total removal rate of fluorine was 99.38%, and the total removal rate of lithium was 1.31%. The purity of the prepared Li2CO3 is greater than 99.5%.