废旧磷酸铁锂电池回收工艺研究

Research on recycling technology of waste lithium iron phosphate battery

以废旧磷酸铁锂正极材料中磷酸锂的回收为目标,设计单因素实验,采用磷酸对废旧磷酸铁锂电池粉末中的锂进行选择性浸出,得出锂元素浸出最佳工艺条件。磷酸浓度为3.41 mol/L,固液比为1∶5,在搅拌速度为500 r/min下,水浴温度70℃浸出3 h,锂元素的浸出率达到94.16%。随后通过氨水调节pH,得出锂元素沉淀最佳工艺条件:pH值为8的浸出液在60℃的水浴温度下反应2 h,沉淀率达到了96.78%。通过单因素实验,降低了实验成本,所设计的回收方案可在一定程度上缩短工艺流程,减少设备投入。

In order to recycle the lithium phosphate in the waste lithium iron phosphate cathode,a single factor experiment was designed,the phosphoric acid was used to selectively leach the lithium in the waste lithium iron phosphate battery powder,and the best leaching process of lithium element was obtained.When the concentration of phosphoric acid is 3.41 mol/L and the ratio of solid to liquid is 1∶5,the leaching rate of lithium element reaches 94.16%under the conditions of the stirring speed of 500 r/min,the water bath temperature of 70℃and leaching for 3 h.The pH was adjusted by ammonia water,and the optimal process of lithium precipitation was obtained.When the leaching solution with the pH of 8 reacts for 2 h at the water bath temperature of 60℃,the precipitation rate reaches 96.78%.Through the single factor experiment,the experiment cost reduces,and the designed recovery scheme can shorten the process and reduce the equipment investment to a certain extent.