Method of vacuum refining of glassy materials with selenium foaming agent
AssigneePPG Industries, Inc.
InventorsRichard L. Gerutti, David R. Haskins, Robert B. Heithoff, Ronald L. Schwenninger, Wright M. Welton
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Abstract
In a method of vacuum refining molten glass or the like, selenium is provided in the molten glass to serve as a foaming agent, which yields improved refining. Alternatively, colored glass compositions that include selenium as a colorant are refined at higher than normal pressures to retain selenium in the glass without sacrificing refining performance.
Claims16
A method of refining glassy materials or the like wherein a stream of molten material is foamed as it is subjected to subatmospheric pressure, the improvement comprising providing in the molten material prior to being subjected to the subatmospheric pressure a quantity of a material selected from the group consisting of selenium, tellurium, and mixtures thereof to enhance the volume expansion of the foam.
A method of making glass including selenium as a colorant comprising:
- melting the glass, subjecting the selenium-containing molten glass to subatmospheric pressure in the range of 100 to 200 torr absolute so as to refine the glass, and passing the refined glass to a forming operation with at least 0.001 percent by weight selenium retained in the glass.
Dependencies are inferred from the claim text.