Recovery of manganese and zinc from waste Zn-C cell powder: Characterization and leaching

A large number of waste Zn-C cells (Haquebrand) were broken down and collected as agglomerated powder. This powder was sun-dried, dry-ground and sieved down to 300 mesh size and stored. The sample was analysed and found to contain (35.4 ± 0.2)% Mn, (11.0 ± 0.1)% Zn and ∼2.5% Fe as major metallic constituents. The phases, ZnMn2O4 and Zn(ClO4)2·2H2O or MnO(OH) were identified in the hot water washed sample. The material was found to be leached effectively by a 2 mol/L sulfuric acid solution containing glucose (2 g/L). However, the dissolution was dependent on (S/L) ratio; and the stage-wise leaching was not fruitful for Mn-dissolution. On leaching 5 g of powder (<53 μm) with a 250 mL of 0.5 g glucose containing 2 mol/L sulfuric acid solution (S/L = 20 g/L), at 100 °C and 300 rpm for 1 h, a solution containing (7.08 ± 0.10) g/L Mn2+, (2.20 ± 0.06) Zn2+ and ∼0.40 g/L Fe3+ was recovered corresponding to cent percent dissolutions of Zn and Mn and 80% dissolution of Fe.