CONVERSION OF BAGASSE FLY ASH TO SODIUM SILICATE

Abstract

This work studied conversion of bagasse fly ash to sodium silicate synthesis and compared the yield of the total sodium silicate from bagasse fly ash (BFA) and acid washed bagasse fly ash (A-BFA). Sodium source employed here was sodium carbonate anhydrous (Na2CO3). Original bagasse fly ash contained mostly silica (63%wt) and other impurities, e.g. Al2O3, CaO, K2O, etc. which could be up to 20%wt. Upon the acid washing with hydrochloric acid, most impurities (16%) was removed. The synthesis of sodium silicate was investigated under the range of operating conditions as follows: precursor mole ratio of SiO2:Na2CO3 of (1:0.50-1:2.25), fused temperature (650-850oC) and reaction time (30-120 minutes). Yields of soluble/insoluble sodium silicate were 38%/18% and 45%/18% for BFA and A-BFA, respectively, which occurred at SiO2:Na2CO3 mole ratio of 1:1.25, fused temperature 830oC and reaction time of 60 minutes.