Simultaneous recovery of valuable components from spent LiNi0.6Co0.2Mn0.2O2 and LiFePO4 batteries by ammonium sulfate roasting-leaching.

Abstract

To further reduce the cost and energy consumption of recycling spent lithium-ion batteries (LIBs), this paper proposes a novel technique for simultaneously recovering Li, Ni, Co, and Mn from spent LiNi_0.6Co_0.2Mn_0.2O₂ (S-NCM) and LiFePO₄ (S-LFP) batteries using ammonium sulfate mixed roasting. Thermogravimetric analysis of the mixture and XRD analysis of the roasting products indicate that (NH₄)₂SO₄ begins to decompose at around 275 °C, forming NH₄HSO₄, which participates in the reaction above 350 °C. Above 375 °C, sulfates are generated as reaction products. FT-IR analysis revealed that the peak at 630 cm^-1, corresponding to metal sulfates in the roasted product, significantly decreased in intensity after leaching, indicating the formation of soluble sulfates. Optimization of the roasting conditions reveals that at a roasting temperature of 400 °C, a roasting time of 60 min, and an ammonium sulfate ratio of 1/1/8, the recovery efficiencys of Li, Ni, Co, and Mn are 94.0 %, 95.6 %, 93.7 %, and 98.7 %, respectively. Energy and environmental analysis using the Ever Batt model demonstrates that the energy consumption of this method is only 52 % of commercial hydrometallurgical processes, and greenhouse gas emissions are only 38 % of commercial pyrometallurgical processes.