Preparation of zinc powder from zinc dross

Residue (zinc dross) generated during galvanization of steel contains about >80 wt% zinc metal. In present paper, zinc powder is produced from zinc dross in an alkaline medium by electrolysis using zinc dross as a consumable anode. In an electrolytic cell various parameters such as current density, current efficiency, voltage and concentration of electrolyte etc. have been optimized. The electrolytic cell was operated at room temperature using 16 g/L Zn, 200 g/L NaOH at current density of 5 A/dm2. The current efficiency was found to be 90% and the purity of zinc powder is 99.5%. This process offers single step recovery of zinc in the form of powder from galvanizing waste.