焙烧水浸法从废旧三元正极材料中选择性提锂

Selective Extraction of Lithium by Roasting-Water Assisted Leaching from Waste Ternary Cathode Materials

针对废旧三元正极材料回收过程中工艺流程长、酸碱消耗高、锂直收率低、回收成本较高等问题,提出了助剂焙烧常温水浸联合新工艺,选择性提取废旧三元正极粉料中的锂,实现锂与其他金属(镍、钴、锰)的高效分离。新工艺以试剂A(无机酸)、试剂B(无机酸盐)为助剂,通过低温煅烧转化与常温水浸技术,提高废旧三元正极材料中锂的直收率,研究了煅烧温度、助剂与正极材料质量比、浸出液固比等条件对金属浸出率的影响。结果表明,在煅烧温度600℃、助剂A添加量为正极材料质量的50%、助剂B添加量为正极材料质量的5%、煅烧时间2h、水浸液固比3mL/g的条件下,Li浸出率达95%以上,浸出液中Li^+浓度21g/L以上,其他金属(Ni、Co、Mn)含量均小于1mg/L。

To address long process flow,high acid and alkali consumption,low direct lithium yield and high recycling cost in present recycling process of waste ternary cathode materials,a novel process to selectively extract lithium from waste ternary cathode materials by roasting and water leaching and efficiently separation with other metals(nickel,cobalt,manganese)was proposed.Recovery rate of lithium rises significantly by adding A(inorganic acid)and B(inorganic acid salt)as additives at low temperature calcination and then water leaching.Effects of calcination temperature,mass ratio of auxiliary agent and cathode materials,and leachate solid ratio on leaching rate of metals were studied.The results show that leaching rate of Li is 95%above under the conditions including calcination temperature of 600℃,mass ratio of A and B to cathode material of 10∶1∶20,calcination time of 2 h,and L/S of 3 mL/g.Concentration of Li^+in leachate is 21 g/L above,and content of other metals(Ni,Co,Mn)is less than 1 mg/L.