Comprehensive recovery of mixed spent of LiNi_xCo_yMn_(1−x−y)O₂ and LiFePO₄

Lithium-ion batteries are currently being scrapped in large quantities, and there are almost no reports of mixed waste disposal. This paper describes research on a comprehensive recovery process for the mixed waste of LiNi_xCo_yMn_(1−x−y)O₂ and LiFePO₄. The interaction of LiFePO₄ and LiNi_xCo_yMn_(1−x−y)O₂ is utilized to achieve selective leaching through a low H₂SO₄-low H₂O₂ system, removal of P and Fe by Fe₂(SO₄)₃-NaOH, preparation of Ni–Co–Mn hydroxide by addition of NaOH, preparation of Li₃PO₄ using Na₃PO₄, and separation of Fe and P by acid. The research shows that when 5.23 ml/g 1 M H₂SO₄ and 0.308 g/g 30% H₂O₂ were added at 90 °C for 5 h, the leaching ratios of Li, Ni, Mn, and Co achieved were 99.589%, 98.524%, 97.079%, and 96.257%, respectively. At 90 °C and a pH 12 for 2 h, the precipitation ratios of Ni, Co, and Mn were 99.79%, 99.89%, and 99.89%, respectively. A total of 55.12 g/l of Na₃PO₄ was added to the solution to effect settling of Li, and a sedimentation rate of 98.46% was achieved. The leaching residue was dissolved in 3 M HCl of 6.62 ml/g, and the achieved leaching ratio of the FePO₄ was more than 95%.