Recovery of Zinc from Galvanized Scraps

Authors: ERCAN AÇMA, SERDAR AKTAŞ

Abstract: The stripping of Zn in sulfuric acidic solutions from galvanized steel products obtained from industry and the removal of impurities from this solution and the conditions required for Zn recovery were experimentally investigated. According to the results,it is possible to completely strip Zn from used galvanized steel products by using sulfuric acid with a pH value of up to 0.2. A solution that contains Zn over 80-85 g/l and Fe 0.2 g/l can be produced by repeated stripping and it is possible to obtain ZnSO_4 from the solution by adding volatile liquid (ethyl alcohol). The precipitated Zn compound is ZnSO_4.H_2O. This compound contains 36.4% Zn and 0.002% Fe and is a raw material pure enough for commercial use. The ethyl alcohol used to obtain ZnSO_4.H_2O from the rich stripping solution is recovered with 90% efficiency through distillation at 78^{o}C for 20 min. This process optimized by the experiments allows for the manufacture of saleable products and causes no environmental problems.

Keywords: Galvanize, Scrap, Stripping, Zinc Salt

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