Advanced Chemical leaching process of Wadi El Dakhal silica sand to produce a high concentration of SiO 2 for electronic industry

Abstract

Abstract Silica sand used in the manufacture of glass, ceramic and porcelain, as well as the high grade SiO2 used in silicon chips, fiberglass and optical lenses, white cement, foundry sand, filters, detergents and pesticides. Egypt possesses a large quantity of silica sand located in Sinai and along the Red sea coast: Zafarana area (Wadi El Dakhal) with SiO2 ranging from 98.60 to 99.00%. This research aims to contribute and increase the added value to the raw silica sand by chemical leaching process to produce high content of SiO2.The evaluation technique of studied silica sand samples includes XRF, XRD, Sieve analysis, physical properties measuring and chemical leaching process using different acids. The leaching process with HCl, (HCl & H2SO4), (HCl, HF, HNO3), [HCl, HF and (COOH)2 ] acids were conducted to beneficiate the raw silica sand and achieve a very good results of SiO2. Wet sieve analysis was completed before chemical leaching to remove fine particles less than 200 um which include clay minerals. The loose of fine particles percent (< 200 um) is around 0.4% from the original silica sand weight. The obtained results indicate upgrading the SiO2 content from 98.60 to 99.99%, and XRD shows the mineral is composed mainly of quartz.