Preparation of amorphous silica gel from Algerian siliceous by-product of kaolin and its physico chemical properties

Abstract

The present work is aimed to achieve valorization of siliceous by-product of Algerian kaolin in the preparation of sodium silicate. This silicate is commonly used as a precursor in silica gel preparation. To prepare sodium silicate, a by-product sample is mixed with sodium carbonate with a molar ratio SiO2/Na2O=3 and heated at high temperature (1000°C). Hydrochloric acid is then slowly added to the hydrated sodium silicate to obtain silica gel. The siliceous by-product and the prepared silica gel are characterized by XRF, XRD, FTIR and BET. The study of porous texture by Nitrogen Adsorption Technique at 77K shows that the specific surface area SBET increases in the silica gel compared to those of kaolin byproduct from 5.6m2g−1 to 477.9m2g−1.