Separation of metals from acetic acid leaching solution of spent lithium-ion batteries by ionic liquid system

Spent Li-ion batteries (LIBs) pollute the environment and endanger human health; however, they are valuable mineral resources. Here, we designed an extraction system composed of 0.4 mol/L 2-thenoyltrifluoroacetone (HTTA), 0.4 mol/L trioctylphosphine oxide (TOPO), and ionic liquid (IL) 1-Butyl-3-MethylImidazolium bis (trifluoromethyl sulfonyl) imide to recover valuable metals from spent LIBs. Under the optimum conditions (O/A = 1/1, 25 degrees C, reaction time 20 min, and pH = 3.65, the pH of the solution does not need to be adjusted), over 99.54% of Co, 99.85% of Mn, and 99.68% of Ni were extracted, while only 2.84% of Li were coextracted. The ultraviolet spectrum analysis showed that the spectral peaks of the stripping solution changed at 266 and 293 nm, indicating that CH3COO- participated in the extraction reaction. Following stripping with sulfuric acid, the pH of the solution was adjusted with 2.0 mol/L NaOH, and approximately 99% of the Al3+ ions were precipitated. Nickel and manganese sulphates were added to the stripping solution. The precursor was prepared using a coprecipitation method. The precursor was then mixed with lithium hydroxide and calcined at 1000 degrees C for 12 h to obtain LiNi1/3Co1/3Mn1/3O2.