Separating metal impurities from spent ternary Li-ion batteries materials based on the roasting characteristics

The existence of metal impurities (Cu, Fe, Al) seriously affects the extraction process of valuable metals in spent Ni-Co-Mn ternary (NCM) materials. Prior to reclaiming valuable metals from spent NCM materials, removing metal impurities is the pivotal precondition for improving recovery efficiency. In this manuscript, the properties of metal impurities in spent NCM materials before and after the roasting are systematically studied. The results of thermogravimetric analysis, XPS analysis, and thermodynamic analysis elaborate that the decomposition products of the electrolyte react with metal impurities to form fluorides, which is unfavorable to the removal of metal impurities. On this basis, a novel route for selective extraction of metal impurities (Cu, Fe, Al) from the spent NCM materials before roasting is proposed, that is, a combined method of magnetic separation, alkaline leaching, and ammonia leaching are used to remove Fe, Al, and Cu in spent NCM materials. Ultimately, the 76.1% Fe, 100% Al, and 100% Cu are removed. The results of leaching thermodynamics further confirm the feasibility and effectiveness of the method. This work displays an efficient and economically feasible approach for removing metal impurities from spent NCM materials, which has great prospects for industrial-scale recycling.