Iron removal from zinc liquors originating from hydrometallurgical processing of spent Zn/MnO2 batteries

In this work, the removal of iron from leach liquors obtained after processing of spent alkaline and zinc-carbon Zn/MnO2 batteries with initial iron ion concentration in the range of 270 to 580 mg/L has been studied. Solid Na2CO3, ZnO and fine ground waste electrode materials separated from processed Zn/MnO2 batteries were tested as precipitation agents. All used precipitation agents make it possible to remove more than 99% Fe, but electrode materials have been found to be more efficient precipitants at lower pH values. The different course of iron precipitation is probably caused by different solubility of iron compounds formed during the precipitation with various precipitation agents. Precipitates in which iron was present as FeO(OH) originated from processing the leach liquors with Na2CO3 or ZnO Precipitates from processing the leach liquors with electrode materials contained zinc-iron non-stoichiometric oxides, which was established as results of experiments performed with a synthetic solution containing 1.54 g/L Fe. nefits of potential use of waste materials containing zinc oxide compounds in applications to remove iron from zinc sulphate liquors would include high efficiency, low cost and good filterability of the formed precipitates.