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- Methods and Techniques
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Introduction The demand for the raw material quartz is increasing worldwide, in particular, the demand for high-purity quartz (HPQ; e.g. /1, 2/). Therefore, quartz has been recently considered as a strategic mineral because it represents the raw material for special applications in high-tech industry. The trace-element contents of quartz are its most important quality criteria. Quartz is designated high purity when it contains less than 50 μg g−1 of impurities /3/, which mainly comprise structurally bound trace elements (B, Li, Al, Ge, Ti, Fe, Mn, Ca, K, Na and P) in the quartz lattice, also micro- inclusions of minerals and trapped fluids. HPQ is rare in nature and larger deposits even more so. The few HPQ deposits found around the world include certain types of quartz-rich granitic pegmatite /4, 5/ and hydrothermal quartz veins. Al and Ti besides Li, P and B are used as indicators of the quality of the quartz. These elements are important quality-determining trace elements depending on the industrial application being considered for the raw material. High Ti concentrations, for example, change the absorption behavior of optical silica glass. Metallic silicon and polysilicon are bred in quartz crucibles, and high P and B concentration in the quartz glass of the crucibles contaminates the growing silicon crystals, which are used for solar cells or computer chips. Moreover, Al, Ti and Li are difficult to remove during refinement of quartz. Therefore, the industry is highly interested in quartz resources with low initial trace-element concentrations to lower production costs and to improve the quality of the quartz products. But when these resources are not available affordable industrial dressing becomes a necessity /6/. Methods and Techniques The methods and techniques that have been applied on the quartz deposits of Wadi Mubarak are: 1) Geochemical analyses by using the XRF technique and 2) Beneficiation processes (Floatation followed by wet magnetic separation). All the geochemical analyses and upgrading processes were carried out in the labs of the Egyptian geological survey. жүктеу/скачать 16,6 Mb. Достарыңызбен бөлісу:
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