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 optimiz...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.展开更多
基金the financial supports from the National Natural Science Foundation of China(Nos.52174338,51904349)the Natural Science Foundation of Hunan Province,China(No.2021JJ30796)。
文摘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.
