恒压酸浸法回收退役锂离子电池废炭渣

Recycling of waste carbon residue from spent lithium-ion batteries via constant-pressure acid leaching

采用恒压酸浸技术,对废炭渣(WCR)进行高效解毒并再生成锂离子电池可用的高纯石墨产品(PGC)。运用正交试验和单因素试验相结合的方法,对浸出条件进行优化。结果表明,在浸出温度为60℃、初始酸浓度为12%、浸出时间为180 min和液固比为25:1的最优条件下,可获得符合商业石墨要求的99.5%纯度石墨产品。同时,以氢氧化钠溶液为沉淀剂,在pH=11的条件下,镍、钴、锰和铝的回收率分别达到96.92%、87.5%、97.83%和92.17%。此外,通过蒸发结晶工艺还可以回收纯度超过99%的NaF副产物。整个流程中氟的损失率小于0.5%,从而消除氟对环境的污染风险。此流程展现了可观的环境效益和经济效益。

Waste carbon residue(WCR)was efficiently detoxicated and regenerated to high-purity graphite(PGC)used in lithium-ion batteries through the constant-pressure acid leaching technique.The leaching conditions were optimized by the combination of orthogonal and single-factor experiments.Results show that PGC with 99.5%purity is regenerated at temperature of 60℃,initial acid concentration of 12%,leaching time of 180 min,and liquid-to-solid ratio of 25:1,satisfying the requirements of commercial graphite.Meanwhile,the sodium hydroxide precipitation process was designed to recover valuable components from leachate efficiently.Ni,Co,Mn,and Al recoveries reach 96.92%,87.5%,97.83%,and 92.17%,respectively,at pH=11.Moreover,the co-product NaF can be recovered with purity over 99%via evaporative crystallization.The loss rate of fluorine is less than 0.5%,thereby eliminating the pollution risk of fluorine to the environment.The proposed process shows considerable environmental and economic benefits.