Separation of Lithium and Transition Metals in Leaching Solution of Used Lithium Ion Battery with Sec‐octylphenoxyacetic Acid.

The recovery of critical metals from spent lithium‐ion batteries (LIBs) is important to sustainable development and environment protection. In this paper, sec‐octylphenoxyacetic acid (CA‐12) was first used to recover valuable metals in LIBs. The effects of phase modifier, initial feed pH, extraction kinetics and thermodynamics, CA‐12 concentration and saponification degree were studied and optimized. Under the optimal conditions, 99 % of nickel, cobalt and manganese were co‐extracted to the organic phase, and the loss of lithium was 7 %. The extracted metal ions could be stripped with 0.04 mol/L HCl equivalently. In the spent LIBs powder leaching experiment, leaching efficiencies of all components were greater than 95 %. In the impurity removal stage, extractant N902 was used to remove copper, while iron and aluminum were eliminated by hydrolysis. After two‐stage extraction, the total extraction efficiencies of nickel, cobalt and manganese reached 99.7 %, 99.4 %, 98.45 %, respectively. Finally, lithium in the raffinate was precipitated by saturated Na2CO3, the purity of recovered Li2CO3 was up to 97.7 %. After 5 times cycles, CA‐12 still maintained excellent extraction capacity, showing its potential application prospects for recovering critical metals form spent LIBs. [ABSTRACT FROM AUTHOR]