Mechanochemical Synthesis of Nano Calcium Silicate Particles at Room Temperature

Nano-sized calcium silicate powders were synthesized at room temperature by the new mechanochemical method using a high energy planetary ball mill. The formation of calcium silicate from its raw materials (calcium carbonate and dehydrated silica gel) was monitored by the XRD analysis with progression of ball milling. It is observed that the synthetic process comes to an end through the following three sequential stages: comminution of raw materials, recombination of comminuted raw materials to final product, and comminution of final product to smaller sizes. The nanostructure of the synthesized powder was realized by the FESEM photomicrograph, TEM image and XRD analyses. These analytical observations have revealed that the nano-sized polycrystalline calcium silicate particles are formed after about 6 h of ball milling and they are spheroidal in shape. The average particle size of the as-generated calcium silicate nanocrystalline powders is found to be around 21 nm which decreases with increasing ball milling but increases with annealing at elevated temperature