LiFePO₄/C粉末盐酸浸出液中主要离子为Li⁺、Fe³⁺与少量的Cl^-，符合TBP萃取Li⁺必须存在过渡族金属离子与Cl^-的理论。探究了TBP萃取Li⁺的机制以及氯离子供给剂、Fe³⁺/Li⁺摩尔比、Cl^-浓度与Li⁺浓度对萃取的影响，得到Li⁺最佳萃取分离条件。结果表明，以FeCl₃+AlCl₃为氯离子供给剂，模拟配制酸浸出液中Li⁺是以[LiFeCl₄]·nTBP的络合形式被萃取；TBP萃取Li⁺的最佳条件为：溶液中Fe³⁺/Li⁺摩尔比为1.5、Cl^-浓度为5 mol/L、Li⁺质量浓度为1 g/L；当相比（O/A）为0.5时，在最佳条件下TBP对LiFePO₄/C粉末盐酸浸出液中Li⁺的二级萃取率达到92%以上，以6 mol/L盐酸为反萃剂三级反萃后Li⁺反萃率约为93%，反萃后有机相中Fe³⁺等杂质质量分数低于1%。该方法使废旧磷酸铁锂电池中的锂分离率达到83%以上，实现废旧磷酸铁锂电池中金属锂资源再生的目的。

To recover lithium metal from cathode active material LiFePO₄/C powder in spent lithium iron phosphate batteries,main ions in the hydrochloric acid leaching solution of LiFePO₄/C powder are Li⁺,Fe³⁺ and a small amount of Cl^-,which accords with the theoretical basis that there must be transition metal ions and Cl^- when TBP extracts Li⁺.The mechanism for TBP to extract Li⁺,and the influences of chloride iron supply agent,Fe³⁺/Li⁺ molar ration,Cl^- concentration and Li⁺ concentration on extraction are explored,and the optimal extraction separation conditions for Li⁺ are obtained.Study results show that using FeCl₃+AlCl₃ as chloride ion supplier,Li⁺ in the simulated acid leaching solution is extracted in the complex form of [LiFeCl₄]·nTBP.The optimal extraction conditions for TBP to extract Li⁺ are as follows:the molar ratio of Fe³⁺/Li⁺ in the solution is 1.5,Cl^- concentration is 5 mol·L^-1,the mass concentration of Li⁺ is 1 g·L^-1.When the ratio of organic phase and aqueous phase (O/A) is 0.5,under the optimal conditions,the secondary extraction rate of Li⁺ in LiFePO₄/C powder hydrochloride acid leaching solution by TBP exceeds 92%;Stripping rate of Li⁺ is around 93% after three-stage of stripping with 6 mol·L^-1 hydrochloride acid as stripping agent,and the mass fraction of impurities such as Fe³⁺ in the organic phase is less than 1% after stripping.This method enables the separation rate of lithium from spent lithium iron phosphate battery to exceed 83%,achieving the regeneration of lithium resources in spent lithium iron phosphate batteries.

王艺博(1993-),女,硕士,工程师,主要从事固废资源化研究,17781480363@163.com