Characterization of dross and its recovery by sulphuric acid leaching

This paper reports the characterization of dross from galvanizing process and its recovery using acidic leaching method. The diffraction profile of dross showed identical peaks with that of ZnO. The X-ray Fluorescence (XRF) analysis identified the content of following metals: Zn, Fe, Mn, Ga, Co, and W. The thermal behaviour examination revealed the existence of some volatiles within the initial sample. The acidic leaching at various concentrations of sulphuric acid was conducted to determine the optimum concentration for zinc recovery and the highest yield of zinc sulphate. It is concluded that the optimum concentration of H₂SO₄ for this kind of dross is 4 M with 71.9% yield of ZnSO₄. The result of leaching process was confirmed by infrared spectrum, where various absorptions corresponding to SO₄ ^2- and Zn-O bands were observed. (paper)