磷酸盐沉淀法从低浓度含锂溶液中回收锂的研究

摘要

The effects of four factors, including pH value, temperature, dosage of trisodium phosphate and salt effect, on the precipitation of lithium ions from the solution with low⁃concentration lithium and high⁃concentration salt were investigated by using phosphate precipitation method. Results showed that lithium precipitation from the solution with low⁃concentration lithium and high⁃concentration salt reached the rate of 95.15%, when the reaction carried out at 90℃by adding trisodium phosphate in quantities of 1.2 times as much as theoretical dosage, with liquid pH value at 8 before reaction. However, lithium precipitation from the solution with low⁃concentration lithium and high⁃concentration ammonium could reach the rate of 96.42%, with the reaction at 90℃ by adding trisodium phosphate in quantities of 1.2 times as much as theoretical dosage, with liquid pH value at 11 before reaction. It is also shown from the experiment that at the temperature of 30 ℃, the salt effect could bring the greatest impact on the lithium precipitation, and the precipitation rate decreases with an increase in the sodium sulfate concentration. This research can be of a theoretical guidance for recovering lithium from low⁃concentration lithium solution.%采用磷酸盐沉淀法从低锂高盐溶液中沉淀锂，研究了pH值、温度、磷酸三钠用量以及盐效应对锂沉淀率的影响。结果表明：对于低锂高钠溶液，在反应温度90℃、磷酸三钠加入量为1．2倍理论用量、反应前液pH值为8时，锂沉淀率达95．15％；而对于低锂高铵溶液，在反应温度90℃、磷酸三钠加入量为1．2倍理论用量、反应前液pH值为11时，锂沉淀率达96．42％。试验还发现：在30℃下，盐效应对锂沉淀率影响较大，锂离子沉淀率随硫酸钠浓度升高而降低。该研究可为回收低浓度含锂溶液中锂提供理论指导。