Journal of Mining World Express (MWE) Volume 5, 2016 www.mwe‐journal.org doi: 10.14355/mwe.2016.05.002
Mineral Industry in Egypt– Part II Non‐Metallic Commodities – Silica Ores Ezz‐El Din, M.1; Abouzeid, A. M.2; El maadawy, Kh .3; Khalid, A.M.4; and El Sherif ., R.E.5 1‐Egyptian Mineral Resource Authority EMRA 2‐ Cairo University, Faculty of Engineering, Dept. of Mining. 3‐ Minofiya University, Faculty of Sciences, Drpt. Of Geology. 4‐Ex‐Egyptian Mineral Resource Authority EMRA 5‐Geologist free hand Abstract Silicon, nowadays, is involved in many advanced and high technology industries due to its unique property. The silica ores exist in the form of quartz, quartzite, and white sand. In Egypt, quartz is confined to igneous and metamorphic origins, while white sand exists in the form of sedimentary deposits. Quartz and quartzite are found in association with basement rocks in Eastern Desert and Western Desert. While white sand deposits are widely distributed in Sinai, Eastern Desert, and Western Desert, with the most commercial deposits in Sinai and Eastern Desert. Estimation of the geological and economic reserves indicate huge tonnages of all types of silica ores. Quartz reserves sum up to 20 million tons, and silica sands sum up to more than 3 billion tons. Evaluation of the chemical and physical characteristics of the silica in Egypt showed high quality silica with low contaminations. The major part of these reserves is available through open‐pit mining with very low costs due to minimal overburden. Some of the silica sand deposits contain a high percentage of white kaolin, up to about 11 percent, which is separated as a valuable economic byproduct. The basic processing operations of the white sand are washing, screening, attrition scrubbing, desliming and dewatering. In some locations magnetic separation is used for the removal of magnetic impurities. Academic research work showed that the quality of the white sand product can be improved when froth flotation operation is used. Keywords Silica Ores in Egypt, Quartz, Quartzite, Glass Sands, Processing of White Sands
Introduction The silica occurrences encompass basically quartz, quartzite and white sand. Silica, nowadays, is essential in high technology industries due to its ability to act as metallic and/or non‐metallic substance. Its unique property makes it one of the most useful natural substances. It is composed of silicon and oxygen, the two most abundant elements in the Earth’s crust, in the form of SiO2. It is composed of silica tetrahedral, and belongs to the rhombohedral crystal type, hexagonal system. The silicon element represents 28.1% of the constituents of the Earth’s crust (Wills, 2006). Silica occurs mostly in a crystalline form and rarely as a non‐crystalline (amorphous) form. In its pure form, it is a colorless, odorless, non‐combustible solid. Crystalline silica has three main crystalline varieties: quartz (by far the most abundant species), tridymite, and cristobalite. The world annual production of silica in 2013 is more than 140 billion tons of industrial silica sands (Dolley, 2013). Figure 1 presents the world production of silica in the period 2007 – 2013. The world production rate ranged from 118 million tons in 2009 to 142 million tons in 2013. Silica ores occur in two forms quartz and white sand. They differ mainly in the origin where quartz is present in igneous rocks as a residual of magmatic activities or hydrothermal solutions, and metamorphic rocks, while white sand is a weathered product of old sedimentary, metamorphic, or igneous origin. Due to this origin white sand could be contaminated with clay minerals in different ratios. As a matter of fact, the strategic importance of silica sands attracted many scientists around the world to investigate the origin of the silica ore deposits, characterize them, and work for improving their grade in practical and economic manners ( Abdallah et al., 1992; Awadh, 2010; Bandel et al., 1987; Blatt et al., 1980; Carver, 1971; El‐Bokl et al., 1993; Ezz El Din, 2007; Issawi et al., 1999; Khalid, 1993; Klitzsch et al., 1990; Madanat et al., 2006; Norton, 1957; Mustafa et al., 2011;
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