This work refers to a process of purification of silica sand and, more particularly, to a process of iron and aluminium removal from the Algerian silica sand particles. Iron compounds are among the most difficult impurities to release from the sand particles. Several methods to remove iron from the sand particles are used; in our work we employed the acid leaching process as optimal solution to purify the silica sand. To this purpose, our work began by characterization of sand samples using X-ray fluorescence, for measurement of concentrations of major mineral oxides, and using atomic absorption, to determine the iron and aluminium concentrations in the silica sand particles. Through this study, the samples were enriched by acid leaching method, by removing the impurities from the crystal lattice, as well as from its surface. Thus reduction the impurities concentration increases, at the same time, the SiO2 concentration. The obtained enriched silica can be used as raw material for silicon production, destined for photovoltaic application.

Extracting quartz from sand, as well as extracting silicon from quartz requires knowledge of the physical and chemical properties of quartz found in the sand. In this work the chemical composition, the crystallographic phase, crystal system, space group, unit cell parameters, the absorption bands, the granulometric analysis and the microscopic observations of quartz in the sand from Mostaganem (Algeria) region have been carried out using X-ray fluorescence, X-ray diffraction, infrared spectroscopy, sifting, optical and scanning electron microscopy in order to determine the rate and the nature the crystallinity of its various components and to discover a layer rich in silica, containing a sufficient reserve to feed a unit manufacturing pure silicon starting from silica. The study is driven by current economic importance of the silicon application in the field of photovoltaic solar cells. The X-ray fluorescence indicates that Mostaganem sand has got a very good purity (99.5% silica). The crystallographic parameters of Mostaganem sand have been determined through analysis of X-ray diffraction. The following parameters were found, hexagonal crystal system, space group P3221, unit cell parameters: a = b = 4.9030 Å, c = 5.3999 Å. The infrared absorption spectrum of studied sand exhibits absorption bands characterizing the SiO2 compound, due to Si-O-Si and Si-O aggregates and others. The granulometric analysis determines the percentage of the various fraction of the grain. The microscopy observation gives the shape of the grain. The results show finally that Mostaganem sand has got good proprieties for the photovoltaic application.

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