Environmentally Friendly Extraction and Recovery of Cobalt from Simulated Solution of Spent Ternary Lithium Batteries Using the Novel Ionic Liquids of [C8H17NH2][Cyanex 272]

An environmentally friendly recycling process of cobalt (Co2+) from simulated solution for spent ternary lithium batteries was demonstrated in this research. The novel task-specific ionic liquids (TSILs) of [C8H17NH2]­[Cyanex 272] were synthesized by one-step reaction of n-octylamine and Cyanex 272. The TSILs have good performance for selective extraction and separation of Co2+. The separation factor of Co2+ and Ni2+ (βCo/Ni) was 976.9 using the two-stage cross-flow extraction, and the extraction percentage of Li+ (E Li) was zero. Efficient selective separation of Co2+ from simulated solution containing Ni2+ and Li+ can be achieved using this environmentally friendly process. High purity CoSO4·7H2O (99.7 wt %) was obtained from the simulated solution using the processes of extraction, stripping, scrubbing, and evaporation crystallization. The conceptual recycling flow-sheet for Co2+ from spent ternary lithium batteries was presented on the basis of the new environmentally friendly extraction process. The mechanism of extractive reaction of Co2+ using the [C8H17NH2]­[ Cyanex 272] was investigated according to the slope method and FT-IR spectra.