硫酸钴共焙烧强化废钴酸锂正极材料中锂的选择性提取

Enhanced Selective Recovery of Lithium from Spent Lithium Cobalt Oxide Cathode Materials Co-Roasted with Cobalt Sulfate

回收废锂离子电池对解决关键金属资源供给、促进新能源行业健康可持续发展具有重要意义。目前废锂离子电池回收工艺存在Li回收率低、需引入外源添加剂及存在二次污染等问题。采用CoSO_(4)作为焙烧助剂从LiCoO_(2)正极废料中提锂的工艺,研究了CoSO_(4)用量、焙烧温度、焙烧时间等焙烧条件及浸出条件等因素对选择性提锂的影响,通过热力学、热化学行为及反应过程物相结构转变等研究对反应机理进行了探讨。结果表明,在物料配比n(CoSO_(4)·7H_(2)O):n(2Li)=1:1、焙烧温度750℃、焙烧时间2 h的条件下,Li的浸出率可以达到98.11%,而Ni、Co、Mn的浸出率均低于0.5%。当CoSO_(4)·7H_(2)O与LiCoO_(2)反应时,先发生CoSO_(4)·7H_(2)O脱水反应,然后CoSO_(4)与LiCoO_(2)反应生成Li2SO_(4)与Co_(3)O_(4)。该工艺具有Li的回收率高、无需引入外源添加剂和无二次污染的优势,浸出后的浸渣可重新回收制备CoSO_(4)实现循环利用,具有工业化应用前景。

Recycling of waste lithium-ion batteries is of great significance in solving the supply of key metal resources and promoting the healthy and sustainable development of the new energy industry.The existing lithium-ion battery recycling process has problems such as low lithium recovery rate,the need to introduce exogenous additives and secondary pollution.The effects of factors such as cobalt sulphate dosage,roasting conditions such as roasting temperature and roasting time,and leaching conditions during the leaching process on the selective extraction of lithium from spent lithium cobalt oxide with cobalt sulfate as roasting additive were researched,and the reaction mechanism was explored through the studies of thermodynamics,thermochemical behaviors,and structural transformations of the physical phases during the reaction process.The results show that the leaching rate of lithium can reach 98.11%,while the leaching rates of nickel,cobalt and manganese are all lower than 0.5%at the material ratio of n(CoSO_(4)):n(2Li)=1:1,roasting temperature of 750℃and roasting time of 2 h.When CoSO_(4)·7H_(2)O reacts with LiCoO_(2),the dehydration reaction of CoSO_(4)·7H_(2)O occurs first,and then the reaction between CoSO_(4)and LiCoO_(2)generates Li_(2)SO_(4)and Co_(3)O_(4).This process has the advantages of high lithium recovery,no need to introduce exogenous additives and no secondary pollution.After leaching,the leach residue can be reclaimed to prepare cobalt sulphate to achieve recycling,and it has the prospect of industrial application.