Abstract:Aluminum is one of the main impurities in leaching solution of cathode material of spent ternary lithium ion battery. Removal of aluminum is an important step in purification and separation of leaching solution. To address serious nickel and cobalt losses, and high cost of aluminum removal by extraction method of traditional aluminum removal by neutralization precipitation, logarithm concentration-pH diagram of Men+-PO43--H2O system (Men+:[Al]T,[Fe(Ⅲ)]T,[Fe(Ⅱ)]T,[Cu]T,[Ni]T,[Co]T,[Mn]T,[Li]T) was established based on thermodynamics data at 298 K. Thermodynamics analysis of process of purifying and aluminum removal from sulfuric acid leaching solution of spent ternary lithium ion battery by phosphate precipitation was conducted. The results show that insoluble phosphate stable zone can be formed within a suitable pH range, and in the range of pH value of 1-4.8, sequence of ions removed by phosphate precipitation is Fe3+＞Al3+＞Cu2+ Fe2+＞Co2+＞Mn2+ Ni2+＞Li+. Phosphate precipitation method can separate aluminum from nickel, cobalt and manganese metals. The experiment results show that precipitation rate of Al, Ni, Co and Mn is 99.86%, 1.35%, 0.99% and 2.09% respectively by 120% theoretical amounts of sodium phosphate at pH=4.0. Phosphate precipitation method is an effective method to remove aluminum from sulfuric acid leaching solution of spent ternary lithium ion batteries.