Process for treating synthetic silica powder and synthetic silica powder treated thereof
AssigneeMomentive Performance Materials Inc.
InventorsRichard L. Hansen, Theodore P. Kircher, Douglas M. Korwin
Life of this patent
Estimating the term…
Abstract
A process for producing a synthetic quartz glass powder which is substantially free of carbon contaminant, for reduced bubble density and improved stability of articles made from the synthetic quartz glass during fusion molding by maintaining the synthetic silica powder in an oxidizing environment, e.g., an atmosphere comprising at least 3 vol. % ozone at a temperature of less than 1400° C., causing carbon containing compounds to be reduced to less than 10 ppm.
Claims24
A method of purifying natural or synthetic silica powder by treating the silica powder in an oxidizing atmosphere comprising at least 3 vol. % ozone at a temperature of greater than 260° C. and less than 1400° C., to reduce carbon containing compound concentration in the silica powder to less than 10 ppm.
A method of purifying natural or synthetic silica by maintaining the silica powder under an oxidizing atmosphere comprising at least 60 vol. % oxygen and ozone at a temperature of less than 1000° C., causing carbon containing compounds to be driven off in gaseous form.
A method of producing synthetic silica having a carbon content of less than 5 ppm by heating a synthetic silica powder containing at least 45 ppm carbon content in an atmosphere comprising at least 3 vol. % ozone at a temperature of at least 200° C.
A method of purifying natural or synthetic silica, said method comprising treating said silica powder at a temperature of greater than 260° C. and less than 1400° C. with a gaseous stream comprising a sufficient amount of ozone to reduce carbon containing purities to a level of less than 5 ppm.
Dependencies are inferred from the claim text.