Demand for strategic metals is increasing rapidly due to the significant advancements in the electronics and automotive industries. One of the most valuable strategic metals, nickel (Ni), is widely used in Li-ion batteries and other applications due to its unique properties, such as corrosion resistance, higher strength, increased storage capacity, and higher energy density. In this study, we investigated the recovery of nickel sulfate hexahydrate (NiSO4.6H2O) via a solvent extraction process followed by evaporative crystallization treatment of pregnant leach solution obtained from the hydrometallurgical treatment of NMC 111 battery black mass. Versatic Acid 10, a carboxylic acid diluted in Isopar L, was used as an organic medium for selective Ni extraction, and > 99 % Ni extraction was accomplished with 0.9 M Versatic Acid 10 at an organic to aqueous (O:A) ratio of 1. Kinetics of the Ni extraction were studied over different time intervals (1 to 15 min) at a constant pH of 6.7. The pure Ni-loaded solution was stripped with 0.2 M sulfuric acid (H2SO4) from the loaded organic solution. The counter-current solvent extraction is being upscaled in the mixer settler with the optimized condition. Evaporative Crystallization was used to recover NiSO4.6H2O with 99.3 % purity at 35 ℃ and a vacuum pressure of 0.1 MPa. The purity and phase of the recovered crystallized powder were analyzed with ICP-OES, ICP-MS and XRD techniques. Recovered crystallized nickel sulfate was found to have potential for use as precursor cathode active materials (pCAM) in nickel-based lithium-ion battery manufacture.
Acknowledgements: This work has been carried out as part of the RESPECT – Flexible, Safe and efficient REcycling of Li-ion batterieS for a comPetitive, circular, and sustainable European battery manufaCTuring industry – project (https://www.respect-recycling.eu/) which has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement No 101069865.