Augmentation de la teneur en silice dans le sable de deux régions de la wilaya d’Adrar

Abstract

The Sahara covers the majority of the Algerian territory; it covers an important natural reserve of silica. In our work we have purified the sand from two regions of the Adrar wilaya such as Fom el Khang and Timimoune. Preliminary analyzes of particle size and X-ray fluorescence of the sand in the two regions revealed that the sand of the two regions is fine-sized and has a high silica content of 93.66% and 95.45% for the sand of Fom el Khang and Timimoune respectively. Two methods of purification have been developed; alkaline fusion using the Na2CO3 flux and acid etching such as; HNO3 / HF / HCl. Both techniques have given good results, but the chemical attack by the acids is efficient. A high silica content is obtained: that the alkaline melting thus a shorter time. For chemical attack, the silica level reached 98.53% and 98.73% for Fom el Khang and Timimoune respectively. Whereas for alkaline fusion 98.45% was obtained for Fom el Khang and 98.34% for the Timimoune region after two alkaline melting treatments.