| 摘要 |
Silica glass granule having the following features: Area: 100 to 5000μm, ECD: 5 to 100μm, Circumference: 20 to 400μm, Maximum diameter: 10 to 140μm, Minimum diameter: 5 to 80μm, where all values are medium values, Specific BET surface area: < 1 m/g Impurities: < 50 ppm. It is prepared by a) compacting pyrogenic silicon dioxide powder with a tamped density of 15 to 190 g/1 to slugs, b) subsequently crushing them and removing slug fragments with a diameter of < 100μm and > 800μm, c) the slug fragments having a tamped density of 300 to 600 g/1, 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. |
