Patent ID: 6705115
Filing Date: 2004-03-16
Classification: C03B,C03C

Abstract:
A process for producing synthetic quartz glass, comprising the steps of:feeding to a reaction zone a silica-forming raw material gas and a fluorine compound gas from a first nozzle at the center of a burner having a plurality of concentric nozzles, oxygen gas from a second nozzle disposed concentrically outside the center nozzle, and oxygen gas or hydrogen gas or both from a third nozzle disposed concentrically outside the second nozzle, flame hydrolyzing the silica-forming raw material gas in the reaction zone to form fine particles of silica, depositing the silica fine particles on a rotatable substrate in the reaction zone so as to create a porous silica matrix, and fusing the silica matrix; wherein the oxygen gas fed from the second nozzle is set at a flow rate with respect to the raw material gas flow rate which represents a 1.1- to 3.5-fold stoichiometric excess of oxygen.