Direct Production of Ni–Co–Mn Mixtures for Cathode Precursors from Cobalt-Rich Lithium-Ion Battery Leachates by Solvent Extraction

A novel solvent extraction scheme was developed for the processing of Co-rich lithium-ion battery (LIB) leachate to a Ni–Co–Mn (NCM) sulfate mixture that can be directly used in precursor synthesis LIB cathodes. Conventional hydrometallurgical recycling spent LIBs usually aims at separation Li, Ni, Co, and Mn into pure fractions, which is simplified here. Operating pH number stages each were evaluated from batch equilibrium experiments. Two continuous countercurrent extractions with bis(2-ethylhexyl) hydrogen phosphate (D2EHPA) one Cyanex 272 studied bench-scale mixer-settler equipment, solution n(Ni):n(Co) = 14.16 n(Ni):n(Mn) 8.06 obtained. The Ni:Co:Mn molar ratio NCM adjusted to, example, 8:1:1 using raffinate same process, no additional transition metal salts are required tuning composition. Stripping containing 102.7 g L−1 Co 99.8% relative purity obtained extraction. main benefit process concept separations operated less stringent requirements than when producing salts.