| 摘要 |
Silica glass granule having the following features: Area: 100 to 5000 μm2, ECD: 5 to 100 μm, Circumference: 20 to 400 μm, Maximum diameter: 10 to 140 μm, Minimum diameter: 5 to 80 μm, where all values are medium values, Specific BET surface area: <1 m2/g Impurities: <50 ppm It is prepared by a) compacting pyrogenic silicon dioxide powder with a tamped density of 15 to 190 g/l to slugs, b) subsequently crushing them and removing slug fragments with a diameter of <100 μm and >800 μm, c) the slug fragments having a tamped density of 300 to 600 g/l, and d) subsequently treating them at 600 to 1100° C. in an atmosphere which comprises one or more compounds which are suitable for removing hydroxyl groups, and e) then sintering them at 1200° C. to 1400° C. |
