FLY ASH WASTE FOR SILICA SYNTHESIS USING THE CAUSTIC METHOD

Abstract

Fly ash is a waste material produced from coal combustion. Generally, coal combustion produces 80% fly ash waste and 20% bottom ash, where the utilization of fly ash waste only reaches 20% of the total fly ash waste produced. Fly ash has chemical content such as SiO2; Al2O3; Fe2O3; with a percentage of 64.97%; 26.64%; 5.69%, respectively [1]. With this content, fly ash is often used to make silica. In this study, silica synthesis used the caustic method (base solvent) with a mass ratio of fly ash (25, 30, 35) grams to determine the effect of fly ash mass on the resulting yield. The solvent used was 3M NaOH, in addition, silica testing was also carried out such as adsorption capacity testing and silica morphology testing. The adsorption capacity test was used to evaluate the silica adsorption capacity, the morphology test was used to determine the diameter and size of silica. The results of the study showed that variations in fly ash mass affected the yield and physical and chemical properties of the silica produced.