Synthesis and Characterization of Nano-Wollastonite from Rice Husk Ash and Limestone

Abstract

Wollastonite, CaSiO3 material was prepared from rice husk ash, as the source for SiO2 and limestone, source for CaO using sol-gel method. Rice husk ash and CaO powder was mixed together in 100ml distilled water with the rice husk ash/CaO ratios of 45:55 and 40:60. The mixed solution was place in the autoclave and heated at 135°C for 4 hours and calcined at 950°C for 1 and 2 hours. From the XRD results,ratio of 45:55 exhibited that b-wollastonite is the major phase and the minor phase is only contributed by cristoballite and by calcining the mixture for 2hrs would yield better crystallinity. Both of the rice husk ash:CaO ratios produced wollastonite materials in cylinder structures. Wollastonite with nano size grain was obtained for an hour calcination and 2 hrs of calcination would increase the grain size over 100 nm for ratio, 45:55 and 40:60.Therefore in order to get the nano size of wollastonite material, period of calcination process has to be controlled.