US 12,246,982 B2
Process for the preparation of synthetic quartz glass
Martin Thürer, Bitterfeld-Wolfen (DE); Walter Lehmann, Kleinostheim (DE); and Martin Trommer, Bitterfelf-Wolfen (DE)
Assigned to Heraeus Quarzglas GmbH & Co. KG, Hanau (DE)
Filed by Heraeus Quarzglas GmbH & Co. KG, Hanau (DE)
Filed on Dec. 16, 2021, as Appl. No. 17/553,143.
Claims priority of application No. 20214478 (EP), filed on Dec. 16, 2020.
Prior Publication US 2022/0185720 A1, Jun. 16, 2022
Int. Cl. C03B 37/018 (2006.01)
CPC C03B 37/01853 (2013.01) [C03B 37/01815 (2013.01); C03B 2201/02 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A process for producing synthetic quartz glass, comprising:
(1) evaporating a feedstock containing at least one organosilicon starting compound to form a feedstock vapor;
(2) feeding the feedstock vapor from (1) to a reaction zone in which the feedstock vapor is burned in a flame from a burner in the presence of oxygen and, if necessary, in the presence of combustible auxiliary gases and is converted to SiO2 soot particles by oxidation or by hydrolysis;
(3) depositing the SiO2 soot particles resulting from (2) on a deposition surface to form a soot body;
if necessary, drying and vitrification of the SiO2 particles resulting from (3) to form synthetic fused silica;
characterized in that in (3), the deposition surface for the SiO2 soot particles is located at a distance from the burner for a period of at least 50% of the build-up time of the soot body, which lies between a position just behind the maximum (viewed from the burner) of the horizontally integrated luminous intensity [in candela/(mm of flame height] of the same flame mentioned above under un disturbed conditions (i.e. with removed deposition surface) up to a position behind the maximum (viewed from the burner) at which the horizontally integrated luminous intensity of the flame is still at least 2/3 of the maximum, wherein the luminous intensity of the flame is measured in candela/(mm2 of flame area).