碳热还原-多段浸提强化废旧锂电材料选择性提锂研究  

Selective recovery of lithium from spent electrode materials by carbothermal reduction combined with multistage leaching

作　　者：袁雪 丁立鑫 刘子孟 姜涛 何亚群[1] 张光文 YUAN Xue;DING Lixin;LIU Zimeng;JIANG Tao;HE Yaqun;ZHANG Guangwen(School of Chemical Engineering and Technology,China University of Mining and Technology,Xuzhou,221116,China;School of Environment Science and Spatial Informatics,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国矿业大学化工学院,江苏徐州221116 [2]中国矿业大学环境与测绘学院,江苏徐州221116

出　　处：《中南大学学报（自然科学版）》2023年第12期4611-4619,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(52104273);江苏省自然科学基金资助项目(BK20200645)。

摘　　要：废旧锂离子电池机械破碎混合电极材料成分复杂,导致选择性提锂效率较低,本研究提出了还原焙烧-多段浸提相结合的锂离子高效选择性提取方法。首先,以混合粉料中的负极材料石墨作为焙烧还原剂,实现正极材料高效还原以及锂离子的转化迁移;然后,通过水浸与碱浸相结合的浸出方式实现锂离子的高效选择性浸出,采用p H调节法沉淀脱除碱浸溶液中的铝离子;最后,采用有氧焙烧-水浸提锂的方法回收沉铝渣中夹带的锂离子。研究结果表明:在700℃热场作用下,混合粉料中的碳粉、残留铝箔等复杂多元物质均影响还原焙烧过程,混合粉料中锂离子的赋存状态包括水溶性Li2CO3、碱溶性LiAlO2、酸溶性LiF等;水浸法可实现75.6%水溶性锂回收,碱浸法可实现10.8%碱溶性锂回收;当pH为6时,可实现锂溶液中铝离子的高效沉淀脱除,有氧焙烧过程可实现沉铝渣中锂离子的析晶,形成可溶性锂盐,而铝则转化为不溶于水的Al2O3,焙烧水浸可实现沉铝渣中95%锂离子的回收。经还原焙烧—水浸—碱浸可实现混合电极粉料中锂离子的选择性提取,有氧焙烧—水浸可实现沉铝渣中夹带的锂离子高效回收,碳热还原—多段浸提后废旧锂电材料中锂离子选择性优先提取效率可达到86.21%。Efficiency of selective lithium extraction was low due to the complex composition of electrode materials derived from the mechanical crushing process of spent lithium-ion batteries.An efficient selective lithium extraction method of reduction roasting combined with multi-stage extraction was proposed.Firstly,the anode material in the mixed powder was used as the roasting reductant to achieve the efficient reduction of cathode material and the transformation of lithium ion.Secondly,high selective leaching efficiency of lithium ions was realized through the combination of water leaching and alkali leaching,and the aluminum ions in alkaline leaching solution were removed by precipitation with pH adjustment method.Finally,aerobic roasting combined with water leaching was employed to recover the lithium ions in the precipitates.The results show that the carbon powder and residual aluminum foil in the mixture affect the reduction roasting process at 700 ℃.After reduction roasting,the chemical states of lithium ions in electrode materials include water-soluble Li2CO3,alkali-soluble LiAlO2 and acid-soluble LiF.Water-leaching method can recover 75.6% of water-soluble lithium from electrode materials,while alkali-leaching method can recover 10.8% of alkali-soluble lithium from electrode materials.The efficient precipitation and removal of aluminum ions in lithium solution can be achieved at the pH of 6.The lithium ions in the aluminum precipitate can form soluble lithium salt in the aerobic roasting process,while aluminum can be converted into water insoluble Al2O3,and the recovery of 95% lithium ions in the aluminum precipitate can be achieved.The selective extraction of lithium ions from the electrode materials can be achieved by reduction roasting-water leaching-alkaline leaching,and the lithium ions contained in the aluminum precipitate can be efficiently recovered by aerobic roasting-water leaching.The selective extraction efficiency of lithium ions from the spent electrode materials can reach 86.21% after carbother

关 键 词：废旧锂离子电池 电极材料 还原焙烧 选择性提锂 多段浸出 

分 类 号：TD982[矿业工程—选矿]