废旧钴酸锂离子电池材料中钴、锂的回收工艺研究

Study on Recycling of Spent Lithiumion Batteries Containing Cobalt and Lithium

针对废旧锂离子电池对环境污染严重、资源浪费大等问题,对锂离子电池材料中的钴、锂回收工艺进行了研究,探索了废旧电池在NaCl溶液中预放电的最佳浓度和时间,对比分析了正极材料与集流体分离的三种方法,优化出酸浸工艺的最佳工艺参数,探索出了钴、锂沉淀的条件.结果显示,废旧电池在1.5 mol/L的NaCl溶液中放电5 h后可降电池电压至安全值;酸浸的最优的工艺参数为C(H+)=3.5 mol/L,C(Na2S2O3)=0.25 mol/L,T=90℃,Time=2.3 h,浸出率可达到了99.5%;采用NaOH溶液将pH调至8.5左右可以将钴离子完全沉淀,得到Co(OH)2沉淀物;采用NaOH溶液调节pH>12,再加入适量的Na2CO3沉淀锂,锂回收率为73%.

With the increase of spent lithium ion batteries,the pressure to the precious metal resource use and environmental pollution is also increasing.The recycling of cobalt and lithium from spent lithium ion batteries is studied.The optimum salt concentration and time of pre-treatment has been explored.Three separation methods of anode material and current collector are compared.The optimum acid leaching process and technological parameters are obtained.The precipitation conditions of cobalt and lithium are also investigated.The results show that the discharge time of spent lithium ion batteries is 5 h in 1.5 mol/L NaCl;the optimum acid leaching technological parameters are:C(H+)=3.5 mol/L,C(Na2S2O3)=0.25 mol/L,T=90℃,time=2.3 h,and the leaching rate of copper is up to 99.5%.Cobalt ions can be completely precipitated by NaOH at pH 8.5.Lithium ions can be precipitated by Na2CO3 at pH>12 adjusted by NaOH,and the recovery rate of lithium is 73%.