TRANSPARENT SILICA GLASS AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a transparent silica glass having high purity and heat resistance and a method of manufacturing the same.

SOLUTION: Raw material powder containing a natural siliceous material and synthetic silica is used. Silicon tetrachloride is added to the raw material powder and fused glass is deposited on a heat resistant base body by oxyhydrogen flame and formed into a transparent silica glass plate shape. The ratio of the natural siliceous material and the synthetic silica is controlled to (3:1)-(1:1). The silicon tetrachloride gas is continuously added in the substantially vertical direction to the fused surface of the fused glass. At least one rectangular cross-sectional through-hole is previously formed below the heat resistant base body. The fused glass deposited on the heat resistant base body flows out from the through-hole to form the plate like transparent silica glass. The silica glass contains≤0.1 ppm each of Fe, Na and K,≤300 ppm OH group and is formed into plate shape with 5-30 mm thick.

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