Recovery of zinc from electric-are furnace dust by leaching with aqueous hydrochloric acid, plating of zinc and regeneration of electrolyte

Synopsis Hot hydrochloric acid solutions were used to extract zinc from electric-are furnace dusts containing zinc oxide and zinc ferrite and to minimize iron dissolution. Fresh electric-are furnace dust was used to remove iron from the filtrate after hot acid leaching. The zinc chloride solutions, purified by activated carbon to remove organics and by metallic zinc powder to remove cadmium, copper and lead, were electrolysed in electrowinning cells that had a cation-exchange membrane to produce high-purity zinc metal and regenerate hydrochloric acid. The spent electrolyte contained 1-2 M HCl and this was used to leach the residue in the hot acid leaching vessel.