Recovery of valuable metals from mixed spent lithium-ion batteries by multi-step directional precipitation

Abstract

The novel strategy of multi-step directional precipitation is proposed for recovering valuable metals from the leachate of cathode material obtained by mechanical disassembly from mixed spent lithium-ion batteries. Based on thermodynamics and directional precipitation, Mn2+is selectively precipitated under conditions of MRNM (molar ratio of (NH4)2S2O8to Mn2+) = 3, pH = 5.5 and 80 °C for 90 min. Ni2+was then selectively precipitated using C4H8N2O2under conditions of pH = 6, MRCN (molar ratio of C4H8N2O2to Ni2+) = 2, 30 °C and 20 min. Then, the pH was adjusted to 10 to precipitate Co2+as Co(OH)2. Finally, Li+was recovered by Na2CO3at 90 °C. The precipitation rates of Mn, Ni, Co, and Li reached 99.5%, 99.6%, 99.2% and 90%, respectively. The precipitation products with high purity can be used as raw materials for industrial production based on characterization. The economical and efficient recovery process can be applied in industrialized large-scale recycling of spent lithium-ion batteries.