The Charachterization of Yazd Dareh Zanjir Zinc Mine Ore for Leaching Purposes

The Dareh Zanjir zinc mine is located at about 25 km south - east of Yazd city and 2 km south - west of Taft town. The aim of this research is to characterize leachability of ore minerals. The results of XRD analysis and microscopic investigation of representative sample and calcined and residue obtained from acidic and alkaline leaching confirmed the presence of dolomite, calcite, smithsonite, cerrussite, hemimorphite, franklinite and willmite. Chemical analysis indicated that zinc grade was about 14 percent that present in the form of smithsonite, hemimorphite, willmite and franklinite. These minerals were soluble in dilute and warm sulfuric acid (except franklinite) and produced zinc sulphate solution. Dissoloution of zinc silicate minerals in sulfuric acid produce silica gel causing problems of decreasing of zinc recovery and filtration rate. Therefore, after the leaching process, the elimination of silica gel should be considered.