Separation of zinc and iron from secondary manganese sulfate leachate by solvent extraction

Purification of concentrated manganese sulfate solution by solvent extraction is discussed in this paper. The use bis(2-ethylhexyl) hydrogen phosphate (D2EHPA) and bis(2,4,4-trimethylpentyl)phosphinic acid (BTMPPA) was studied removal impurities from zinc electrowinning anode sludge leachates. Over 99 % iron were removed both extractants at around pH 3 two mixer-settlers operating continuous countercurrent mode a solvent-to-feed (S/F) ratio 0.43 T = 22 ± 1 °C. BTMPPA had higher selectivity for over than D2EHPA under all experimental conditions. Extraction typically below 10 can be limited crowding the extractants, since fraction loaded decreased decreasing organic to aqueous volumetric (O/A). A significant amount co-extracted Mn recovered selective stripping with 0.5 M sulfuric acid. more sensitive adjustment D2EHPA. Increasing mean residence time mixer 3.6 min 6.0 improved but change little or no effect on