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

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)(2)S2O8 to Mn2+) = 3, pH = 5.5 and 80 degrees C for 90 min. Ni2+ was then selectively precipitated using C4H8N2O2 under conditions of pH = 6, MRCN (molar ratio of C4H8N2O2 to Ni2+) = 2, 30 degrees C and 20 min. Then, the pH was adjusted to 10 to precipitate Co2+ as Co(OH)(2). Finally, Li+ was recovered by Na2CO3 at 90 degrees 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.