废旧三元正极粉的氢碳协同还原提锂机制  

Mechanism of lithium extraction by hydrogen-carbon synergistic reduction of spent LiNi_(x)Co_(y)Mn_(z)O_(2) cathode powder

作　　者：刘晓剑 马亚赟 周向阳 杨娟 贺跃辉[2] 唐晶晶 LIU Xiaojian;MA Yayun;ZHOU Xiangyang;YANG Juan;HE Yuehui;TANG Jingjing(School of Metallurgy and Environment,Central South University,Changsha 410083,China;Powder Metallurgy Research Institute,Central South University,Changsha 410083,China;Hunan Provincial Key Laboratory of Nonferrous Value−added Metallurgy,Changsha 410083,China)

机构地区：[1]中南大学冶金与环境学院,湖南长沙410083 [2]中南大学粉末冶金研究院,湖南长沙410083 [3]湖南省有色增值冶金重点实验室,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2023年第5期1669-1679,共11页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51802354,51871247);湖南省自然科学基金资助项目(2022JJ40610)。

摘　　要：针对废旧三元正极粉,选用氢气和碳作为共还原剂,通过调控还原产物组成,达到高效优先提锂的效果,研究氢和碳在正极粉还原过程中的协同提锂机制。研究结果表明:在气体流量0.3 L/min、碳含量1.88%、焙烧温度600℃、焙烧时间1 h的最优条件下,废旧三元正极粉被还原为Ni、Co、MnO和LiOH,碳含量和焙烧温度参数的调控对正极粉的还原以及锂物相的转变至关重要。在反应温度为25℃、液固比为5:1(mL/g)、反应时间为20 min的条件下,锂的浸出率达到93.4%,而其他金属均留在渣相中。基于不同锂盐溶解度的不同,采用碳化沉淀的方法处理提锂液,得到了纯度为99.7%的Li_(2)CO_(3)产品。The hydrogen and carbon were chosen as co-reducing agents to achieve preferential lithium extraction from spent LiNi_(x)Co_(y)Mn_(z)O_(2) cathode powder by regulating the reduction drive of both,and the synergistic lithium extraction mechanism of hydrogen and carbon in the reduction process of cathode powder was investigated.The results show that the spent LiNi_(x)Co_(y)Mn_(z)O_(2) cathode material is reduced to Ni,Co,MnO and LiOH under the optimal conditions of gas flow rate of 0.3 L/min,carbon content of 1.88%,roasting temperature of 600 ℃ and roasting time of 1 h.The parameters adjustment of carbon content and calcination temperature are very important for the reduction of cathode powder and the transformation of lithium phase.The leaching efficiency of lithium reaches 93.4% at 25 ℃ for 20 min with liquid-solid ratio of 5:1(mL/g),while all other metals remain in the slag phase.Based on the different solubility of different lithium salts,the Li_(2)CO_(3) product with 99.7% purity is obtained from lithium extraction solution by carbonation precipitation method.

关 键 词：废旧锂电池 协同还原 选择性提锂 水浸 碳酸锂 

分 类 号：TF813[冶金工程—有色金属冶金]