Efficient recovery of spent LiFePO₄ cathode powder using salt leaching-oxidation cycle process

In order to realize the efficient and low-cost recycling of spent LFP cathode powder, the spent LFP cathode powder was recovered through the salt leaching-oxidation cycle process. FeCl₃ was used as the leaching agent, and the FeCl₂ in the leaching solution was oxidized back to FeCl₃ using H₂O₂, enabling the regeneration of the leaching agent. Under optimized conditions, the leaching efficiency of Li reached 99.56% in the first leaching cycle and remained at 97.37% after ten cycles. The residue was crude FePO₄. The purer LiCl solution was obtained by adding KOH to precipitate Fe²⁺, Fe³⁺, and Al³⁺ in the final leaching solution, and the concentration of Li⁺ was 4.80 mol·L⁻¹. Economic evaluations of three methods, i.e., salt leaching-oxidation cycle, selective lithium extraction by acid leaching, and coupled salt leaching-extraction, revealed that the salt leaching-oxidation cycle process consumes less water and incurs lower costs, making it highly promising for industrial application.