Recovery of manganese and zinc from waste Zn-C cell powder: Mutual separation of Mn(Ⅱ) and Zn(Ⅱ) from leach liquor by solvent extraction technique

摘要

Acidic organophosphorous extractants were screened for the mutual separation of Mn(Ⅱ) and Zn(Ⅱ), in a leach solution of waste Zn-C cell powder. This was done using a 2 mol/L H_2SO_4 solution containing 2 g/L glucose. Extraction characteristics of both metal ions in this mixture have been examined as functions of equilibrium pH. Although tech. and anal, grade D2EHPA are not so effective for the separation, PC88A, Cyanex 272, Cyanex 302 and Cyanex 301 are all promising for this purpose. Strippings of Mn(Ⅱ) and Zn(Ⅱ) from the extracted organic phases have been examined, using 0.25, 0.50 and 1 mol/L H_2SO_4; and 1 mol/L HCl, HNO_3 and HCIO_4 at different phase ratios. H_2SO_4 appears to be the best stripping agent A 1 mol/L H_2SO_4 solution strips almost 100% of target metal ions in 10 min, regardless of the extractant used. As ΔpH_(1/2) - 2.75 and as the max. separation factor (β) -1793 for Cyanex 302 at pH_((eq)) = 4.0, a flow sheet has been developed for their mutual separations. Finally, classical precipitation methods have been adopted to obtain MnS and ZnS, which can be easily oxidized to MnO_2 and ZnO, respectively.