Patent ID: 7070748

Claim:
A process for producing non-porous spherical silica comprising following steps (1)–(7): (1) a step of emulsification comprising: preparing a water-in-oil type (W/O type) emulsion in which an aqueous solution of alkali silicate is dispersed in the form of fine particles as a dispersed phase; (2) a step of coagulation comprising: mixing the water-in-oil type (W/O type) emulsion prepared in step (1) with 15–20% by weight of an aqueous solution of mineral acid and thereby forming spherical silica gel so that the concentration of the mineral acid comes to 10% by weight or more after the reaction; (3) a step of extraction comprising: heating the reaction mixture containing the spherical silica gel formed in step (2) at a temperature not lower than 50° C. and thereby extracting impurities; (4) a step of washing comprising: washing the spherical silica gel from which the impurities have been extracted in step (3); (5) a step of drying comprising: drying the spherical silica gel washed in step (4); (6) a step of disintegration comprising carrying out disintegration with a screen at the time of the drying or after the drying of step (5); (7) a step of calcinating comprising: calcinating the spherical silica gel disintegrated in step (6).