从废旧锂离子二次电池中回收钴和锂

Recovery of cobalt and lithium from spent lithium-ion secondary batteries

采用碱溶解→酸浸出→P204萃取净化→P507萃取分离钴、锂→反萃回收硫酸钴和萃余液沉积回收碳酸锂的工艺流程,从废旧锂离子二次电池中回收钴和锂。实验结果表明:碱溶解可预先除去约90%的铝,H2SO4+H2O2体系浸出钴的回收率达到99%以上;P204萃取净化后,杂质含量为Al3.5mg/L、Fe0.5mg/L、Zn0.6mg/L、Mn2.3mg/L、Ca<0.1mg/L;用P507萃取分离钴和锂,在pH为5.5时,分离因子βCo/Li可高达1×105;95℃以上用饱和碳酸钠沉积碳酸锂,所得碳酸锂可达零级产品要求,一次沉锂率为76.5%。

The separation and recovery of metal values such as cobalt and lithium from spent lithium-ion batteries were investigated. The results show that more than 90% of aluminum is removed by alkali dissolution, leaching efficiency of more than 99% of cobalt and lithium can be achieved when H_2SO_4+H_2O_2 solution is used at 80 ℃. The impurties in the leach liquor is extracted selectively and nearly completely with D2EHPA. The concentrations of impurties are decreased as low as Al 3.5 mg/L, Fe 0.5 mg/L, Zn 0.6 mg/L, Mn 2.3 mg/L and Ca <0.1 mg/L, respectively. The cobalt in the liquor is extracted selectively with PC-88A in kerosene at equilibrum pH≈(5.5,) and the Co/Li separation factor is as high as 1×10~5. It is followed by stripping with H_2SO_4 solution. The raffinate is concentrated and the lithium remaining in the aqueous is readily recovered as lithium carbonate precipitate by the addition of a saturated sodium carbonate solution at 95 ℃.