Chlorination and evaporation behaviours of zinc and lead at chlorinating and oxidising atmosphere

Abstract

Treatment of electric arc furnace (EAF) dust has become an important issue from the viewpoint of environmental protection and recycling of valuable resources because EAF dust contains considerable amount of zinc and lead. A new recovery process of these metals has been proposed, in which the metals in the dust react with waste polyvinyl chloride, and the produced metal chlorides are removed as gaseous species from the oxide residue. Therefore, it is important to clarify the chlorination and evaporation behaviours of zinc and lead in the chlorinating and oxidising atmosphere. In the present study, the kinetics of chlorination of ZnO, PbO and ZnFe₂O₄, which are the main constituents containing Zn and Pb in the EAF dust, were measured from 1023 to 1373 K with Ar–O₂–Cl₂ atmosphere. Based on these results, the selective chlorination and evaporation process of zinc and lead from the mixture of Fe₂O₃–ZnFe₂O₄–ZnO–PbO was examined at 1073 K with Ar–Cl₂–O₂ atmosphere, and the high efficiency of selectivity was demonstrated.