Method of producing synthetic quartz glass

USRE30883E · kind E · reissue

Assignee

• Heraeus Quarzschmelze GmbH · DE

Inventors

• Karlheinz Rau · Hanau, DE
• Fritz Simmat · Gelnhausen, DE
• Albert Muhlich · Frankfurt, DE
• Norbert Treber · Kriftel, DE

Key dates

• Filing date: Feb 13, 1980
• Grant date: Mar 16, 1982
• Expiry date: Feb 13, 2000

Classification

• Technology area (CPC —): General

Abstract

An improvement in a method for producing a synthetic hydroxyl ion-free quartz glass wherein a hydrogen free silicon compound is heated in a hydrogen-free gas stream while the gas stream is passed through an induction coupled plasma burner, the gas stream containing elemental and/or bound oxygen and the oxidation product is deposited on a refractory support as a vitreous mass, the improvement lying in including in the gas stream a gaseous hydrogen-free, thermally decomposable compound which yields fluorine in an amount of at least 500 gms. per kilogram of silica to be produced; an apparatus for producing a synthetic OH ion-free quartz glass comprising an induction coupled plasma burner which burner has disposed thereabout 3 concentric quartz glass tubes disposed in stepped configuration of which the outermost tube is the longest and the innermost tube is the shortest. The apparatus includes means for passing through the innermost tube a hydrogen-free gas stream containing elemental oxygen and/or bound oxygen together with a gaseous hydrogen free thermally decomposable compound which yields fluorine. The apparatus further contains means for passing a separating gas such as oxygen thr…