Recovery of Cobalt, Nickel and Copper Compounds from UHT Processed Spent Lithium-ion Batteries by Hydrometallurgical Process

Lithium-ion batteries (LIBs) are employed in various electronic devices and industries. The recovery of valuable metals from spent LIBs has attracted much interest due to potential environmental issues and economic values. Metallic alloys can be obtained from the UHT process of spent LIBs. In this study, a hydrometallurgical process was developed for the recovery of metal compounds from synthetic metallic alloys containing Co, Ni, and Cu. This process consisted of leaching, solvent extraction, stripping and precipitation. First, the metallic mixtures were completely leached by the mixture of 2.0 moL center dot L-1 HCl and 10%(v/v) H2O2 solutions at 60 degrees C. Metal ions in the leachate were sequentially separated by solvent extraction with 0.7 moL center dot L-1 Cyanex301 and 1.0 moL center dot L-1 Aliquat 336 for Cu(II) and 1.0 moL center dot L-1 ALi-SCN for Co(II), whereas Ni(II) was remained in the final raffinate. The compounds of Cu(II) and Co(II) were recovered from the respective loaded organics by precipitation stripping method, while Ni(II) compounds were recovered by precipitation from the final raffinate without changing its acidity. Mass balance of the whole process indicated that the recovery percentage of metal compounds such as CuC2O4, CoCO3, and NiC2O4 center dot 2 H2O was 98.6, 99.4, 99.8% from the leaching solution and the purity of the compounds was higher than 99.9%. A process was proposed for the recovery of pure metal compounds from spent LIBs. The advantages of this process are the possibility that metal compounds with high purity can effectively be synthesized and the aqueous raffinates and the stripped organic solutions after each step can be recycled.