High-selectiveseparation recovery of Ni, Co, and Mn from the spent LIBs via acid dissolution and multistage oxidation precipitation.

Abstract

For recovering Ni, Co, and Mn from lithium-ion batteries, traditional chemical precipitation methods demonstrate low selectivity and significantly contribute to environmental pollution. This study proposes a separation recovery technique for transition metals, specifically Ni, Co, and Mn, from spent LIBs, involving "acid dissolution" and "multistage oxidation precipitation". More than 98% of transition metals can be extracted from spent LIBs using a low acid concentration (0.5 M) without reducing agents. The feasibility of separating different metals via multistage oxidation precipitation, based on their different electrode potentials for oxidizing Me2+(Me = Mn/Co/Ni), was confirmed. The combination of oxidizing agent S2O82- andthe precipitant OH- was universally applied to the fractional precipitation of Mn, Co, and Ni respectively. About 99% of Mn, 97.06% Co, and 96.62% Ni could be precipitated sequentially by changing the concentrations of S2O82-and the pH value of solution. XRD, XPS, XRF, ICP-MS and other methods were employed to elucidate the mechanism behind the multistage oxidation precipitation of target metal compounds,exploiting the differential electrode potentials for oxidizing Me2+ions. This technique surpasses traditional solvent extraction in cost-effectiveness and selectivity, showing promise for large-scale industrial applications in recovering Mn, Co, and Ni.