Effect of Dry Grinding of a CaO-Silica-gel Mixture on Synthesis of Para-Wollastonite by Heating

摘要

A powder mixture of calcium oxide(CaO) andsilica-gel (amorphous SiO2) was subjected to grinding under dryatmospheric condition using a planetary ball mill to investigate itseffect on synthesis of para-wollastonite (CaO·SiO2) powder byheating. The grinding of the mixture changes a crystalline structureof CaO into amorphous one within 5 hours. Accordingly, themixture ground for 5 hours aggregates with homogeneouschemical composition, leading to the formation of a precursor ofpara-wollastonite by heating at 923K. Para-wollastonite can besynthesized by heating the mixture ground for 2 hours at 1,273Kfor 2 hours. while heating at around 1,400K for about one week isnecessary to synthesize it from the original mixture.