Abstract
Room temperature grinding of a mixture composed of calcium hydroxide and silica-gel with different water contents was conducted in a planetary ball mill. Afwillite, Ca3 (SiO3 (OH)) 22H2O, is synthesized by controlling water content of 23-30% by 2-hour grinding. The 2-hour grinding of the mixture containing more than 38% of water enables us to synthesize mechanochemically other different types of calcium silicate hydrates. Thermal behavior of the ground mixture containing afwillite is quite stable till around 1000 K. The mixture decomposes at around 1100 K, forming wollastonite, Ca3 (Si3O9), while those ground for less than 90 minutes are changed into ε-wollastonite.
