Optimization of chemical precipitation for valuable metal recovery from spent lithium nickel manganese cobalt oxide batteries

Abstract

This study investigated the optimized conditions for chemical precipitation to recover nickel manganese cobalt hydroxide (NiCoMn-OH) and lithium carbonate (Li2CO3) from spent lithium nickel manganese cobalt oxide (sLi-NMC) batteries. The research focused on establishing optimized conditions to maximize recovery efficiency and product purity. The process involved dismantling and incinerating the batteries to produce black powder, followed by acid leaching using H2SO4 and H2O2, and a two-step precipitation to recover NiCoMn-OH and Li2CO3. Results indicated that the optimized incineration conditions for efficient black powder production were 600 °C for 30 min. During the leaching process, the optimized extraction of lithium, nickel, cobalt, and manganese was achieved using 1 M H2SO4 with 2% H2O2 at a liquid-to-solid ratio of 30:1 mL/g. In the first precipitation stage, the optimized conditions for co-precipitating the solid NiCoMn-OH using saturated NaOH were identified as pH 10, 25 °C, and a contact time of 90 min. The results showed that nickel, manganese, and cobalt were precipitated at 92.04%, 90.35%, and 86.78%, respectively (a purity of 98.67%). Finally, lithium was successfully recovered as Li2CO3 using saturated Na2CO3, at pH 12, 100 °C, and a contact time of 120 min up to 96.51% (a purity of 98.98%). Ultimately, the optimized conditions obtained from this study can provide valuable data for waste management and serve as a comparative baseline for environmental impact assessment of conventional metal recovery, enabling direct comparisons with optimized alternative methods in future research.