退役锂电池正极材料选择性回收锂全元素分布分析

All-element Distribution Analysis of Selectively Recover Lithium from Decommissioned Lithium Battery Cathode Material

采用硫酸焙烧水浸工艺对退役锂电池正极材料进行选择性回收锂,并从混酸硫化、焙烧、水浸各阶段对正极材料全元素分布进行分析。分析结果表明,硫酸焙烧水浸工艺的优先提锂效果良好,锂元素在液相中占比大于91%。在混酸和焙烧过程中,部分正极材料粉末会随混酸烟气和焙烧气体进入烟尘,造成一定的损失,尤其是钴、镍、锰、锂元素在烟尘中总占比为1%~1.5%。除去烟尘导致的损失,铁、铜、铝、锌全部存在于渣相。钠、钾液相和渣相的分布占比相似。硅、镁、钙液相中有极少量,绝大数分布在渣相。镉、铬、铅引入量极少,液相中占比只有1%左右。氟、氯绝大部分分布在烟尘中,磷有90%以上分布在渣相。碳、硫在烟尘中的占比均较大。全元素分布研究可以为退役锂电池正极材料回收整体工艺提供技术参考。

Sulfuric acid roasting and water leaching process was used to selectively recover lithium from decommissioned lithium battery cathode material,and the all-element distribution of cathode material was analyzed from the phases of acid mixing and sulfurization,roasting,and water leaching.The analysis results show that the sulfuric acid roasting and water leaching process has a good effect of prioritizing lithium extraction,and the proportion of lithium element in the liquid phase is more than 91%.In the process of acid mixing and roasting,part of the cathode material powder will enter the soot with the acid mixing flue gas and roasting gas,resulting in certain losses,especially cobalt,nickel,manganese and lithium elements in the soot with a proportion of 1%~1.5%.Apart from the loss caused by soot,all iron,copper,aluminum and zinc exist in the slag phase.The distributions of sodium and potassium in the liquid phase and slag phase are similar.Silicon,magnesium and calcium are present in the liquid phase in very small quantities,and most of them are distributed in the slag phase.Cadmium,chromium and lead are introduced in very small quantities,accounting for only about 1%in the liquid phase.The vast majority of fluorine and chlorine,is distributed in the soot,phosphorus has more than 90%of the distribution in the slag phase.Carbon and sulfur are both larger in the soot.The study of all-element distribution can provide technical reference for the overall process of recycling cathode material of decommissioned lithium battery.