核桃壳低温还原辅助废NCM正极金属浸出的研究

Study on the Leaching of Spent NCM Cathode Metals Assisted by Walnut Shell-based Low Temperature Reduction

针对废旧三元锂离子电池中有价金属进行高效回收的瓶颈问题,本研究提出以生物质为还原剂的低温碳热还原强化正极材料中有价金属浸出的方法,探讨了核桃壳作为还原剂的低温碳热还原预处理对废旧NCM523正极金属浸出回收效率的影响。结果表明,在450~500℃的较低温区,混合物较核桃壳或废旧NCM523存在明显的相变峰,还原产物中的Li_(2)CO_(3)经水洗后即可高效回收;再经柠檬酸酸洗后,Ni、Co和Mn分别有45.53%、47.49%和90.08%进入到酸洗液中而实现浸提回收。

Concerning the bottleneck problem of efficient recovery of valuable metals in spent ternary lithium-ion batteries,a method of low-temperature carbothermal reduction with biomass as reductant to strengthen the leaching of valuable metals in cathode materials was proposed.The effect of low-temperature carbothermal reduction pretreatment with walnut shell as reducing agent on the leaching and recovery efficiency of metals from spent NCM523 cathode was studied.The results showed that there is an obvious phase transition peak in the mixture than walnut shell or spent NCM523 in the lower temperature range of 450~500℃.Li_(2)CO_(3) in the reduction product can be recovered efficiently after water washing;After washing by citric acid,45.53%,47.49%and 90.08%of Ni,Co and Mn could be recycled from the leaching solution,respectively.