以废旧NCM523型电池正极材料浸出液制备NiCo2O4和Li2CO3研究

采用湿法冶金方法回收废旧NCM523型锂离子电池正极材料中的镍、钴和锂, 正极材料的硫酸浸出液经净化除杂后, 采用“水热沉淀-煅烧法”制备NiCo₂O₄, 再采用化学沉淀法回收锂。研究了添加剂种类、水热温度及时间、煅烧温度对产物形貌的影响。结果表明, 以电极材料硫酸浸出液为原料, 以草酸作沉淀剂、六次甲基四胺作表面活性剂, 在140 ℃下水热反应4 h, 得到NiCo₂O₄前驱体; 前驱体在300 ℃下煅烧2 h, 得到形貌均匀的棒条状NiCo₂O₄材料; 采用饱和Na₂CO₃溶液沉淀水热反应母液中的锂, 得到Li₂CO₃。该工艺初步实现了废旧电池正极材料中有价金属镍、钴和锂的回收利用。

Preparation of NiCo2O4 and Li2CO3 from Leaching Solution of Cathode Material of Spent NCM523 Battery

Nickel, cobalt and lithium were recovered from cathode materials of spent NCM523 batteries by using a hydrometallurgical approach. And the sulfuric acid leaching solution of the cathode material was purified to remove impurities, and then used to prepare NiCo₂O₄ by adopting a process consisting of hydrothermal precipitation and calcination. Subsequently, a chemical precipitation approach was adopted to recover lithium therein. In the experiments, the influences of type of additives, hydrothermal temperature, reaction time and calcination temperature on the morphology of the product were investigated. With leaching solution of the cathode material as the raw material, oxalic acid as the precipitator and hexamethylenetetramine as the additive, hydrothermal reaction at 140 ℃ for 4 h produced precursors, which were then subjected to calcination at 300 ℃ for 2 h, yielding NiCo₂O₄ bars with uniform morphology. Finally lithium was precipitated from the mother solution of hydrothermal reaction, with the product of Li₂CO₃ obtained. It is concluded that recycling of valuable metals of nickel, cobalt and lithium from spent NCM523 batteries can be actualized by using this technical process.