Study of Leachability of Heavy Metals from Zinc Flotation Plant Tailings Dam Sediments

摘要

The risk of soil, surface, and ground water contamination by toxic metals leached from mineral processing plants' solid waste is a major environmental concern. In this research the most important factors that affect the leachability of toxic heavy metals from the sediment of a tailing dam in a zinc flotation plant in the city of Arak in central Iran have been studied. The leachability of heavy metals such as Zn, Cd, and Pb were examined. Potential leachability, defined as the maximum metal pool that may become available for leaching at a constant pH decreased in the following order: Pb ＜ Zn ＜ Cd. The results indicated that the highest risk of leachability in Pb and Cd were obtained when the pH in the input solution was 5 while for the Zn the highest mobility was at a pH of 7. The experimental results were statistically analyzed using Statistical Package for Social Sciences (SPSS 15) software. The results of SPSS software indicated that the Zn and Cd removal times were the most effective parameters in the leachability of toxic metals from the sediment. The results of the model also indicated that flow rate, acid concentration and time have little effect on the removal of Pb from sediments in the range of experimental data.