Study on the Geopolymerization of Geothermal Silica and Kaolinite

Geothermal plant produces numerous kinds of possible side products. One of them is silica as a consequence of the existing silica scaling problem which causes geothermal power plant efficiency depletion. The silica recovery possesses a way to utilize it. Geopolymer concrete is a solution to utilize the abundance recovered geothermal silica with low energy consumption and green house gas emission. Thus, in this study, the geopolymerization of geothermal silica and kaolinite will be observed. Geopolymer was inorganic polymer consist of Si and Al atoms that formed through polymerization process. The raw materials being used are geothermal silica as amorphous silica source and kaolinite as alumina source, whereas the activator composed of sodium hydroxide and sodium silicate. Geothermal silica possesses amorphous structure which had been proven by X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) analysis with 96.09% silica (SiO2) content and 18.92% alumina (Al2O3) content of kaolinite. The experiment conducted to determine geopolymerization rate of geothermal silica and kaolinite reaction in presence of alkali activator with certain composition and temperature variation ranged from 80°C up to 120°C. Study on geopolymerization rate was carried out by observing geopolymer bond along with the compressive strength as a function of curing time and temperature. As for geopolymer bonds for each sample with different curing temperatures, FTIR and SEM analysis were used to investigate.