Spent LiFePO₄ batteries valorization: integrated process for battery-grade FePO₄ production

To address the long-standing challenges in recycling spent LiFePO₄ batteries, this study proposes an integrated process. Alkaline pressure leaching enables selective Li extraction, while simultaneously removing Al to achieve deep Fe-Al separation; P and Fe are enriched in the residues. Subsequent H₂SO₄ leaching attains 99.2 % P and 94.8 % Fe extraction efficiency, with Ca transformed into construction-grade CaSO₄·2H₂O. TBP and Lix984 facilitate > 99 % removal of F and Cu via multi-stage extraction, resulting in raffinate with F/Cu concentrations < 2 mg/L. Finally, H₂O₂ at 3times the theoretical dosage oxidizes Fe²⁺, and crystallization yields battery-grade FePO₄. The full-process recovery efficiencies of Li, Fe, and P were 97.88 %, 92.91 %, and 95.49 %. This process enables full-element recovery and exhibits good suitability for industrial-scale application.