Selective separation and recovery of lithium, nickel, MnO₂, and Co₂O₃ from LiNi₀.₅Mn₀.₃Co₀.₂O₂ in spent battery

• Main Authors: He, Hongping, Feng, Junli, Gao, Xiaofeng, Fei, Xunchang
• Other Authors: School of Civil and Environmental Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Environmental engineering; Selective Recovery; Hydrometallurgy
• Online Access: https://hdl.handle.net/10356/159649
• Institution: Nanyang Technological University

The recovery of valuable metals from the LiNi0·5Mn0·3Co0·2O2 in spent batteries deserves more attention. We report a series of feasible procedures to selectively recover the four metals (Li, Ni, Mn, and Co) using a combination of hydrometallurgical and pyrometallurgyical processes. Firstly, oxalic acid is used to dissolve Li and precipitate the other three metals in oxalate forms. It is found that under the optimal condition, about 98% of the Li is dissolved, and on average 93% of the other three metals are transformed to precipitated oxalates. The oxalates are then transformed to NiO·Mn2O3·Co3O4 by being calcinated at 723 K under atmospheric environment. The selective recovery of NiO·Mn2O3·Co3O4 can be achieved by using H2SO4 under three different conditions. The first step is to use H2SO4 to selectively dissolve CoO from the Co3O4. Then the combination of H2SO4 and ultrasound is adopted to dissolve NiO, during which the ultrasound destroys the surficial oxide film on the NiO. Afterwards, the Mn2O3 is transformed to MnO2 and Mn2+ in heated H2SO4. The Co, Ni and Mn ions are dissolved in a sequence, which facilitates their separation and recovery. As the main components of the final residual solids, Co2O3 and MnO2 present in distinctly different sizes and shapes, which are beneficial for their separation and direct usage.