| 摘要 |
The synthetic amorphous silica powder of the present invention is characterized in that it comprises a synthetic amorphous silica powder obtained by applying a spheroidizing treatment to a granulated silica powder, and by subsequently cleaning and drying it so that the synthetic amorphous silica powder has an average particle diameter D 50 of 10 to 2, 000µm; wherein the synthetic amorphous silica powder has : a quotient between 1.35 exclusive and 1.75 inclusive obtained by dividing a BET specific surface area of the powder by a theoretical specific surface area calculated from the average particle diameter D 50 ; a real density of 2.10 to 2.20g/cm 3 ; an intra-particulate porosity of 0 to 0.05; a circularity between 0.50 inclusive and 0.75 inclusive; and a spheroidization ratio between 0.20 inclusive and 0.55 exclusive. This synthetic amorphous silica powder is less in amount of gas components adsorbed to surfaces of particles of the powder and in amount of gas components within the particles, so that a synthetic silica glass product manufactured by using the powder is remarkably decreased in amount of generation or degree of expansion of as bubbles even upon usage of the product in a high temperature and reduced pressure environment. |
