synthetic wollastonite beta, method of preparation and its application in ceramics and as fillers and pigments

摘要

Substantially pure, synthetic crystalline alpha -wollastonite having a specified BET surface of 1-30 m2/g made by first producing calcium silicate hydrates having a molar ratio of SiO2:CaO = about 0.7 to about 1.3 by hydrothermal treatment of an aqueous mixture of a source of CaO and SiO2 and then annealing the calcium silicate hydrates at about 800 DEG C to about 1150 DEG C to convert them to the alpha -wollastonite. The invention also encompasses the use of the calcium silicate hydrates and the alpha -wollastonite in the manufacture of ceramic materials and glazings.