Direct electrodeposition of zinc from galvanised steel scrap

Galvanised steel is widely used in automotive indistry and construction equipment. Scrap of zinc coated steel is generally purchased, together with non-galvanised scrap, to be used as charging material in electric steelmaking. The zinc introduction into EAF causes problems due to zinc trapping in the flue dust that increases costs of compliance with environmental regulations and that makes not easy dust return to the furnace. Thus, developing a process to remove zinc from steel scrap before feeding EAF could be of great interest. In this work a power assisted process to obtain a selective zinc dissolution has been studied. On the grounds of previous works that allowed to determine the best chemical and electrochemical parameters for steel dezincing, a direct electrodeposition of zinc has been studied. The effect on process yield and deposit morphology of electrolyte composition, current density, cell structure and type of anode support-system has been investigated. The results appear interesting: by performing only one operation, current efficiency of about 90% and specific energy consumption of about 0.5 kWh/kg of produced zinc are obtained.