Hydrometallurgical process for zinc reco

This study presents the development of a purification process aimed at recovering high-purity zinc from electric arc furnace dust (EAFD) by means of electrowinning, building on findings from a prior study involving agitation leaching with diluted sulphuric acid. The methodology consists of four key unit operations: first, the removal of iron is achieved through chemical precipitation of crystalline basite sulphate salt at atmospheric pressure, with specified conditions of pH 3.5 and 95 °C. Subsequently, the zinc is extracted using Cyanex 272 at pH 3.5 and 40 °C with a 25% extractant concentration. The loaded organic phase is stripped using a zinc point electrolyte in diluted H2SO4 at the same temperature. Finally, zinc electrowinning occurs from sulphate solutions at 38 °C, utilizing aluminum as the cathode and lead as the anode, while maintaining an electrolyte acidity of 180 g/L H2SO4 and a current density of 500 A/m². The research underscores the significance of hydrometallurgical processes in recycling efforts, particularly in light of increasing environmental regulations concerning waste disposal.