Recovery of Fe, Mn, Ni and Co in sulfuric acid leaching liquor of spent lithium ion batteries for synthesis of lithium ion-sieve and NixCoyMn1-x-y(OH)2

A comprehensive utilization process of Fe, Mn, Ni and Co in the acid leaching liquor of spent lithium ion batteries was put forward. Fe and part of Mn were extracted to synthesize Fe-doped lithium ion-sieve. Ni, Co and the rest of Mn were coprecipitated to prepare ternary lithium ion battery cathode material precursor NixCoyMn1-x-y(OH)2. After removing Cu2+ ions in acid leaching liquor by adding MnS, two-stage counter current extraction and one-stage stripping were used to extract all Fe3+ and 40.3% of Mn2+ ions in sulfuric acid leaching solution to obtain a MnSO4 stripping solution containing Fe3+ ions. Iron-doped lithium ion-sieve was synthesized by oxidation of the resulting MnSO4 solution with KMnO4 followed by roasting and acid leaching. Fe incorporates into the lattice of lithium ion-sieve and improves the structure stability. Fe-doped lithium ion-sieve shows Li adsorption capacity of 35.29 mg.g−1 and Mn dissolution loss of 1.66%. The Li+ adsorption in salt lake brine with the Fe-doped ion-sieve follows a pseudo-second-order kinetic model. NixCoyMn1-x-y(OH)2 is regular spherical particles with β-Ni(OH)2-like structure. This process provides a simple method for recovery and utilization of Mn, Fe, Ni and Co in spent lithium ion batteries.