Removal of Zn(II) from manganese-zinc chloride waste liquor using ion-exchange with D201 resin

Manganese-zinc chloride waste liquor (MZCWL) produced during cobalt smelting is a significant source for the preparation of high-purity manganese sulfate. The key to recover manganese from MZCWL is the separation of Zn(II). Conventional methods for zinc removal are unsatisfactory due to similar physicochemical properties of zinc and manganese. In this study, a complexation ion-exchange approach was developed to selectively extract and separate zinc from MZCWL. Theoretical analysis suggested that zinc existed as non-cationic chloride complexes (ZnCl20, ZnCl3-, and ZnCl42-) under a high chloride concentration. They can be adsorbed by an anion-exchange resin, while manganese still existed in the form of divalent cation. Herein, D201 resin was used to selectively adsorb zinc from MZCWL. The adsorption was significantly affected by chloride concentration, contact time, resin dosage, and temperature. Moreover, the Langmuir isotherm model fitted the adsorption best with a maximum zinc adsorption capacity of 158.98 mg.g(-1) at room temperature. In addition, SEM-EDS and Raman analysis further revealed that Zn(II) was adsorbed by D201 resin in the form of zinc chloride complexes. This work provides an alternative and feasible approach for the separation of zinc from chloride medium.