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| a) Chemical analyses
Seven representative quartz samples from Marwat Alimikan area were chemically analyzed (Table 1). From Table 1, the SiO 2 content ranges between 99.25 and 99.60% with an average content 99.46%, TiO 2 content is < 0.01%, Al 2 O 3 content ranges between 0.15 and 0.28% with an average 0.20%, Fe 2 O 3 content ranges between 0.01 and 0.04% with an average 0.02%, CaO content ranges between 0.08 and < 0.01 with an average 0.05%. Therefore these composite quartz materials, without treatments, match well the requirements of the following industries: Aluminum alloy industry (Si minimum 98 wt%, Fe maximum 0.02–0.05 wt% and Ca from 0.015–0.3 wt % /5/ ) and Ferrosilicon alloy industry (SiO 2 > 98%, Al 2 O 3 < 0.4%, Fe 2 O 3 , CaO and MgO ≤ 0.2% /6/). From the above chemical results it is clear that the quartz deposits of Marawat Alimikan are compared to those that are classified as pure (SiO 2 99% to < 99.5%) to very pure (SiO 2 ≥ 99.5%) quartz /7/as the result of SiO 2 content which ranges between 9925 to 99.60%. The analyzed quartz samples also show abnormal contents of Zr, Cr, Cu and Ni. This content has a negative effect on the process of transferred efficiency of quartz into solar cells /8/. This negative has to be treated during quartz processing. b) Thermal behavior Four quartz samples were subjected to differential thermal analysis to detect their thermal behavior versus thermal gradient (Table 2). The given analyses show that the mineral constituent of the analyzed samples is quartz with total loss of ignition due to heating up to 1000°C ranging between 0.089 and 0.412%. The DTA curve of the studied samples indicates that the quartz is of α -type, where the endothermic peaks on the curve show that the temperature ranges between 572.78° C to 575.03° C (Fig. 2). жүктеу/скачать 16,6 Mb. Достарыңызбен бөлісу:
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