| 摘要 |
PROBLEM TO BE SOLVED: To efficiently raise the bulk density of silica powder, to improve the handleability and to reduce the transportation/distribution cost, etc., by treating silica powder by a vibratory ball mill. SOLUTION: Silica powder obtained by grinding natural silica by a high- temperature decomposition method or a wet precipitation method is fed through a powder supply hopper 2 by a powder pump 1, an air transportation, etc., to the vibratory ball mill 3 equipped with a partition plate 5 for separating balls 6 from the silica powder in the interior at an outlet side. The silica powder is treated by vibrating the vibratory ball mill 3 for 2 seconds to 10 minutes retention time under 2,000-5,000 kg vibration force in 15-35 mmϕball diameter at 3-30% ball packing fraction in 500-1,000 balls at 20-150 kg/hour silica powder feed rate, continuously or intermittently discharged from an outlet to give silica powder having >=0.3 kg/l bulk density. Consequently silica by-product silica powder in production of synthetic quartz can be reused and the manufacturing cost of synthetic quartz can be reduced.
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