Recovery of Lithium and Manganese from Scrap LiMn₂O₄ by Slurry Electrolysis

Recycling of lithium and others metals from lithium-ion battery scraps are significant to prevent resource depletion and environmental protection. In this study, slurry electrolysis was employed for the recovery of lithium and manganese from the scrap LiMn 2 O 4 without addition of the chemical reductant or oxidant. The effect of electric current density, acid concentration, pulp density, and MnSO 4 concentration on Li and Mn leaching efficiency and electrode current efficiency was investigated. More than 99 and 92% of Li and Mn were leached at 363 K, and the current efficiency of the cathode and anode can reach 77 and 62%, respectively. Phase analysis indicated that pure MnO 2 was deposited in 1.0 mol/L H 2 SO 4, and LiMn 2 O 4 cannot be leached into Mn 2+ directly. The leaching of Mn 2+ from scrap LiMn 2 O 4 involves the steps of Li leaching and MnO 2 leaching. Finally, a closed-loop process was proposed for the recovery of high purity of Li 2 CO 3 (99.59 wt %) and MnO 2 (92.33 wt %) from scrap LiMn 2 O 4 . This process is economically feasible, environmentally friendly, and has great potential for the recovery of other scrap cathode metals.