Hydrometallurgical treatment of electiric arc furnace dust in aim of zinc separation

Abstract

During the steel production from secondary raw materials in the electric arc furnace, generation of the main intermediate of the process- dust from the electric arc furnace (EAF dust) occurs. This dust contains significant amounts of Zn and Fe, as well as Pb, Ca, Mn, Ni, Cu, Cd, Mg, Si, Cr, F, Cl and other elements and is considered hazardous industrial solid waste since it contains heavy metals. In order to separate Zn as a valuable component, hydrometallurgical treatment of EAF dust was investigated.The treatment consists of two stages: 1st stageis water leaching of EAF dust performed in order to remove water-soluble compounds, and 2nd stage is acid leaching in order to leach ZnO from EAF dust and obtain a ZnSO4solution. With optimal parameters of the water leaching process of EAF dust, the achieved leachingrates of water-soluble compounds are as follows: 80.84% Cl, 60.63% K, 52.95% Na, 18.23% Ca, while with acid leaching of the solid residue obtained after water leaching at optimal parameters achieved leaching rate of Zn is 82.34%. In addition to the economic aspect of this treatment where the separation of Zn from EAF dust is performed, the treatment also has an ecological aspect because the transformation of hazardous waste into non-hazardous waste is performed, which has a positive effect on the environment.