Recovering valuable metals from the leaching liquor of blended cathode material of spent lithium-ion battery

Abstract

Blended cathode material for lithium-ion battery has been widely applied in electric vehicles, but effectively recovering valuable metals from the leaching liquor of blended cathode material is difficult due to the high content of manganese. In this study, an effective approach for recovering valuable metals from high-manganese leaching liquor of spent blended cathode materials is proposed. Firstly, 97.5% nickel and 100% cobalt in high-manganese leaching liquor are co-precipitated by sodium ethyl-xanthate under the optimum conditions of pH=5, 2 h, 50 °C and the dosage of sodium ethyl xanthate of 55 g·L-1. Then, over 95% nickel in precipitate is selectively leached into solution while almost 100% cobalt is still left in precipitate through a two-step ammonia leaching under the conditions of 2 mol·L-1 ammonia, 50 g·L-1 ammonium sulfate, L/S=8 ml·g-1, 1 h and 40 °C. Finally, the manganese and lithium left in leaching liquor are separated by solvent extraction. Over 99% manganese is effectively extracted and separated from lithium on the conditions of 40% vol D2EHPA, pH=5, 25 °C, the ratio of organic to aqueous (O:A)=1.25 and extraction time of 10 min. The whole recovering process is facile and can help effectively recycle lithium, nickel, cobalt and manganese from spent blended cathode materials.