Method of manufacturing granulated silica powder, method of manufacturing vitreous silica crucible

摘要

The present invention provides a method of manufacturing a vitreous silica crucible having a transparent layer by use of waste vitreous silica, and silica powder suitable for the manufacturing. According to the present invention, there is provided a method of manufacturing granulated silica powder comprising a process for pulverizing waste vitreous silica generated in the manufacturing process of a crucible to form silica fine powder having an average particle diameter of 100 µm or less, and a process for granulating the silica fine powder to obtain granulated silica powder having an average particle diameter of 50 µm or more under helium atmosphere, wherein the average particle diameter of the granulated silica powder is twice or more larger than the average particle diameter of the silica fine powder.