Abstract
We investigate a purifying process of silica which plays a critical role as a starting material in the industry of glass and high-grade silicon. This method is a subsequent combination ofthermal treatment and acid leaching. First, Tabuk natural sand samples were submitted to rapid thermal annealing in an infra-red furnace under O(2)atmosphere at fixed temperature900 degrees C during 1 h (to weaken impurity -Si bands). Subsequently, the samples were soaked in an aqueous acid solutioncomposedof hydrofluoric acid and nitric acidconcentration. This last acid leaching step was intended to remove the gettered impurities during the annealing step. Chemical compositions of the treated samples were analyzed by energy-dispersive X-ray diffraction (XRD) and energy dispersive X-ray(EDX) spectroscopy. Surface morphology was determinedby scanning electronic microscopy (SEM). The result indicates that all undesirable impurities in silica were successfully removed.