Sangwon Enc Co.

Hyeun Bum Jo

Ho In Lee

Dong Soo Baik

The process uses hydrochloric acid solutions to extract zinc from electric arc furnace dusts containing zinc oxide and zinc ferrite. To selectively leach zinc and minimize iron dissolution by precipitating as FeO.OH and Fe O , hot acid leaching with the aqueous solution containing 37 g/l-74 g/l HCl and 104 g/l-270 g/l ZnCl is used. New dust is introduced to remove iron from the filtrate of the hot acid leaching. The zinc chloride solutions purified by activated carbon and metallic zinc powder is electrolysed in electrowinning cells which had cation exchange membrane to produce high purity zinc metal and to regenerate hydrochloric acid. Electrolysing an aqueous solution of zinc chloride with Zn concentration of 50-130 g/litre below 40&deg; C. in a cell divided by cation exchange membrane, whereby coherent zinc is yielded at the cathode with high current efficiency of exceeding 90%. HCl is directly regenerated with a very small loss below 2% and low energy consumption below 5.0 kWh/kg-Zn during Zn-electrodeposition at a cathodic current density in the range of 300-2000 A/m , and a membrane current density in the range of 750-2000 A/m . The spent electrolyte with 1-2N HCl is used to leach the residue in the hot acid leaching vessel.

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Seoul, South Korea

Hyeun Bum Jo