亚磷酸低共熔溶剂浸出钴酸锂正极材料  

Leaching of lithium cobaltate cathode material with phosphite eutectic solvent

作　　者：何喜红 谷坤 康涛 李林波[1] 李倩[1] HE Xihong;GU Kun;KANG Tao;LI Lingbo;LI Qian(School of Metallurgical Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学冶金工程学院,西安710055

出　　处：《中国有色金属学报》2024年第12期4079-4089,共11页The Chinese Journal of Nonferrous Metals

基　　金：陕西省自然科学基础研究计划资助项目(2021JM-370)。

摘　　要：低共熔溶剂(DES)具有对金属氧化物溶解能力强、制备方法简单、废液污染小等优点,因而在回收废旧锂离子电池(LIBs)正极材料领域备受关注。本文以氯化胆碱(ChCl)为氢键受体,以亚磷酸(PA)为氢键供体合成了一种新型的DES,采用其浸出钴酸锂(LiCoO_(2))正极材料中的Li和Co。考察了DES的组成、浸出时间、温度以及液固比对浸出过程的影响,并利用紫外-可见吸收光谱、红外吸收光谱和离子色谱等手段分析了浸出机理。结果表明:亚磷酸DES的黏度低,其中n(PA)∶n(ChCl)=4∶1的DES在20℃下的黏度为155 mPa·s,并且该DES对LiCoO_(2)的浸出速率快、浸出效率高,在浸出温度为80℃、液固比为80 g/g的条件下,只需浸出20 min,Li和Co的浸出率分别为99%和97%。在浸出过程中,DES中的亚磷酸能够将LiCoO_(2)中的Co3+还原为Co^(2+),亚磷酸自身被氧化为磷酸,Co^(2+)在浸出液中以[CoCl_(4)]^(2-)的形式存在。Deep eutectic solvents(DES)have attracted significant attention within the areas of cathode material recovery from spent lithium-ion batteries(LIBs),owing to their remarkable properties of good dissolving capacity for metal oxides,simple synthesis procedures and low pollution.In this work,a novel deep eutectic solvent composed of choline chloride(hydrogen bond acceptor,ChCl)and phosphorous acid(hydrogen bond donor,PA)was synthesized,and the leaching performances of lithium and cobalt from lithium cobalt oxide(LiCoO_(2))using the DES as lixiviants were studied.The effects of DES composition,leaching time,temperature,and liquid-tosolid ratio on leaching efficiencies were investigated,and the leaching mechanism was analyzed by UV-Vis spectra,FTIR spectra and ion chromatography.The results indicate that the phosphite-based DES(n(PA)∶n(ChCl)=4∶1)exhibits an exceptionally low viscosity of 155 mPa·s at 20℃.Meanwhile,the leaching kinetics is fast and the leaching efficiency is high for leaching of LiCoO_(2)by the DES.At a leaching temperature of 80℃,a liquid-tosolid ratio of 80 g/g and a leaching time of only 20 min,the leaching efficiencies for lithium(Li)and cobalt(Co)reach 99%and 97%,respectively.During the DES leaching process,Co3+in LiCoO_(2)is reduced to Co^(2+)by phosphorous acid while it is oxidized to phosphoric acid,and Co^(2+)is present as[CoCl_(4)]^(2-) in the leaching solutions.

关 键 词：亚磷酸 低共熔溶剂 钴酸锂 回收 

分 类 号：TF816[冶金工程—有色金属冶金] X705[环境科学与工程—环境工程]