Purification of Zinc Oxide from Chlorides Using Microwave Radiation

Abstract

Waelz oxide is a secondary zinc raw material and a product of Electric Arc Furnaces (EAF) dust, copper smelters dust and zinc production residues. The use of Waelz oxide in the traditional RLE (Roasting-Leaching-Electrowinning) zinc production scheme requires the removal of halogens (fluorides and chlorides). Waelz oxide is mainly composed of zinc oxide, also contains zinc chloride. Zinc chloride is removed into the gas phase at heating. Microwave heating is one of the promising methods. Test experiments of microwave heating of a ZnO-ZnCl2 mixture were carried out. It was shown that zinc chloride absorbs microwave radiation; zinc oxide does not absorb microwave radiation. The degree of zinc chloride removal from ZnO-ZnCl2 mixture was 100%.