China Nonferrous Metallurgy

Spent lithium-ion batteries are not only rich in lithium, cobalt, nickel and other important metal resources, but also contain heavy metals, organic pollutants, etc. The synergistic leaching scheme of the existing literature usually introduces impurity elements such as phosphorus and rare earth, which makes the metal separation process more complicated. In this study, lithium cobalt oxide waste with oxidability and cobalt white alloy waste with reducibility were taken as the research objects, and the experimental study on the synergistic leaching of lithium cobalt oxide waste-cobalt white alloy was carried out. The effects of mass ratio of cobalt white alloy and lithium cobalt oxide waste, sulfuric acid concentration, leaching temperature, leaching time and other factors on the synergistic leaching were investigated, and the mechanism of leaching process was discussed. The results show that under the conditions of mass ratio 0.25, sulfuric acid concentration 1mol/L, leaching temperature 60℃, leaching time 1h, solid-liquid ratio 50g/L and stirring rate 375r/min, the leaching efficiencies of Li, Co, Cu and Fe can reach 99.83%, 97.51%, 95.36% and 75.6%, respectively. The 2+ produced by the dissolution of cobalt white alloy in the synergistic leaching process plays a reducing role, which promotes the dissolution of LiCoO₂, and the generated Fe³⁺ form FeOOH precipitation. This method not only achieves synergistic leaching, but also reduces the introduction of chemical reagents, which provides theoretical and technical support for the clean and efficient utilization of waste lithium ion batteries and cobalt white alloys.