| 摘要 |
A process for producing a silica vessel which comprises: a step in which an aluminum compound or a crystal nucleator is added to a first raw material powder, which is silica particles, thereby giving a mixture powder; a step in which the mixture powder is fed to the inner wall of an outer mold having holes for evacuation, while rotating the outer mold, thereby preforming the mixture powder into a given shape; a step in which the preform is degassed by evacuation from the periphery side and, simultaneously therewith, the preform is heated to a high temperature from the inner side thereof to convert the peripheral part of the preform into a sintered object and the inner part into a molten glass object and thereby form a silica base; and a step in which while spraying a second raw material powder, which has a higher silica purity than the first raw material powder, from the inner side of the silica base, the silica base is heated to a high temperature from the inner side to thereby form a transparent silica glass layer on the inner surface of the silica base. Thus, a silica vessel having high dimensional accuracy and high durability and reduced in gas emission is produced from inexpensive and relatively low-grade silica powders as the main raw material at low cost using a small amount of energy. |
