Effect of Acidic salts on Characteristics of Precipitated Silica from Geothermal Sludge

Abstract

This research was carried out to produce precipitated silica from sodium silicate using acidic salt as precipitator. The aim of this research is to study the effects of acidic acid on precipitated silica characterization. The sodium silicate solution was produced by extraction of geothermal sludge using sodium hydroxide 2N solution. Precipitated silica products were characterized by x-ray diffraction, x-ray fluorescence and scanning electron microscopy. The results showed that the silica precipitated prepared by aluminum sulfate solution (1-3N) is a silica-alumina composite, amorphous structure and about 0.5 millimicron particle size. Precipitated silica with a concentration of 91-99 %SiO2 can be produced from sodium silicate solution using 1-3N sodium dihydrogenphospate solutions, have an amorphous structure and 1-2 millimicron particle size. Microscopically precipitated silica prepared by aluminum sulfate has a softer structure than that of precipitated silica prepared by sodium dihydrogen phosphate.