| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a synthetic amorphous silica powder suitable for raw material of a synthetic silica glass product in which bubbles are little generated or little expanded even when the glass product is used in a high temperature and reduced pressure environment, and to provide a method for producing the synthetic amorphous silica powder. <P>SOLUTION: The synthetic amorphous silica powder is obtained by firing a granulated silica powder, subjecting the fired silica powder to spheroidizing treatment and then cleaning and drying the resulting silica powder, and has an average particle diameter D<SB>50</SB>of 10 to 2,000 μm. The synthetic amorphous silica powder is characterized by: having a value, which is obtained by dividing the BET specific surface area by the theoretical specific surface area as calculated from the average particle diameter D<SB>50</SB>, of 1.00 to 1.35, true density of 2.10 to 2.20 g/cm<SP>3</SP>, intragranular porosity of 0 to 0.05, circularity of 0.75 to 1.00, and a spheroidization ratio of 0.55 to 1.00; and satisfying either or both of <2 ppm carbon concentration and <2 ppm chlorine concentration. <P>COPYRIGHT: (C)2011,JPO&INPIT |
