Optical and spectroscopic characterizations of Algerian silica raw material to predict high quality solar-grade silicon

We assess the potential use as raw material for photovoltaics of Algerian silica samples from the quartz veins of the Tirek deposit and quartz sandstones of the Ain Barda deposit. With 97–98% purity, they all require enrichment before their industrial utilization. Acid leaching and gravimetric separation are used to remove the impurities at the grain boundaries and within the crystal lattice. We obtain course, middle, and fine products. The acid leaching process and the gravimetric separation increase the content of SiO2 up to 99.68%; the residue concentration of iron, alumina and zirconium is decreased to 70, 72 and 58 ppm respectively. These values are in agreement with requirements for silica as raw material destined for solar-grade silicon production. •Optical and microscopic characterizations reveal structural defects and mineral inclusions.•Leaching and the gravimetric separation increase the content of SiO2 up to 99.68%.•Residual impurities concentration value in enriched silica Fe, Al and Zr