微波焙烧强化废锂离子电池中的金属回收研究

Research on the effect of microwave roasting on recovery of valuable metals from cathode materials of spent lithium ion batteries

为进一步提高资源回收效率和降低能耗,围绕废锂离子电池正极材料中有价金属的资源回收问题,提出对废锂离子电池正极材料进行微波焙烧前处理以强化提高各有价金属的浸出效率.结果显示,在不同微波焙烧功率条件下均存在最优焙烧时间以获得最佳金属回收率.综合考虑工序、能耗、成本等因素,研究确定微波焙烧功率600W,焙烧时间6min为较优微波焙烧处理条件,以H_(2)SO_(4)+H_(2)O_(2)为浸出体系,固液比为20g/L,反应温度为80℃,反应时间为60min条件下,Li、Ni、Co、Mn的浸出率分别达96%、85%、76%、52%.微波焙烧对废锂离子电池正极材料中有价金属浸出效率的强化效应主要来源于以下三方面的共同作用:其一,金属颗粒在微波作用下放电产生瞬时高温;其二,在瞬时高温条件下部分金属发生还原反应转化为更易于浸出的化学形态;其三,包覆在物料颗粒表面的有机物得以高效去除,提高金属裸露程度.

Focusing on the metal recovery from the cathode material of spent lithium-ion batteries,microwave pre-treatment was proposed in this study to improve metals recovery efficiency.The results showed that different microwave power had its optimal treatment time,which could lead to high recovery efficiency of metals.Combined with process,energy consumption,cost and other factors,microwave roasting power with 600W and roasting time with 6min were determined to be the optimal pretreatment conditions.Under the conditions of H_(2)SO_(4)+H_(2)O_(2) as leaching system,solid-liquid ratio with 20g/L,reaction temperature with 80℃and reaction time with 60min,the leaching rates of Li,Ni,Co and Mn reached 96%,85%,76%and 52%,respectively.The enhancement effect of microwave treatment on the leaching rate mainly came from the interaction of the following aspects:the instantaneous high temperature generated by the discharge of metal particles,the reduction reaction of metals and the removal of organics coating on the surface of material particles at the instantaneous high temperatures.