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AssigneeTosoh Quartz Corporation
InventorsChiemi ITO, Takeshi MUTOU, Masahiro SATO, Takaya SUZUKI, Minoru KUNIYOSHI
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A method for manufacturing a large sized opaque quartz glass ingot having excellent heat ray shielding and light blocking properties without using a foaming agent. The obtained opaque quartz glass has small diameter spherical bubbles and a preferable mechanical strength. Silica powder is dispersed in water to form a slurry having a silica powder concentration of 45 to 75 wt % and the average particle size of the silica powder is adjusted to 8 μm or less and the standard deviation of the particle size is adjusted to 6 μm or more by wet pulverization. The slurry is sprayed for forming granules of the silica powder. An opaque quartz glass ingot with a small bubble diameter and high mechanical strength is obtained by melting the granulated silica powder.
A method for manufacturing an opaque quartz glass including melting granulated silica powder in which silica powder is dispersed in water at 45 to 75 wt % is spray-dried and granulated by wet pulverization controlling the average particle size of 8 μm or less and the standard deviation of the particle size to 6 μm or more, and melting the obtained granulated powder.
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