Patent ID: 6698244
Filing Date: 2004-03-02
Classification: C03B,C03C

Abstract:
A glass melt refining method for refining glass, said glass consisting essentially of a member of the group: aluminosilicate glass, borosilicate glass, soda-lime glass, and glass ceramic material, said method comprising the steps of:(a) forming a melt of molten glass by heating glass to a temperature above the melting point of the glass; (b) adding a refining agent to form refining gas in said melt in a quantity sufficient to produce a sufficient volume of refining gas in said melt of molten glass at a temperature above about 1600 degrees Celsius to refine said melt of molten glass, said refining agent consisting essentially of a member of the group: (I), (II), (III), and combinations thereof, wherein (I) comprises redox compounds, said redox compounds comprising redox oxides, said redox oxides consisting essentially of a member of the group and combinations thereof: SnO2, CeO2, Fe2O3, ZnO, TiO2, V2O5, MoO3; WO3, Bi2O5, PrO2, Sm2O3, Nb2O5, Eu2O3, TbO2, and Yb2O3, (II) comprises metal oxides, said metal oxides consisting essentially of a member of the group and combinations thereof: ZnO, As2O3, Sb2O3, Bi2O3, and SnO2, (III) comprises inorganic salts, said inorganic salts comprising halides, said halides comprising at least one and combinations of: chlorides, fluorides, and rare earth fluorides, consisting essentially of a member of the group and combinations thereof: KCl, CaCl2, BaCl2, LaCl3, CeCl3, YbCl2, ErCl3, PrCl3, and said fluorides comprising at least one and combinations of: LiF, NaF, KF, ZnF2, MgF2, BaF2, CeF3, and rare earth fluorides; (c) refining said melt of molten glass at a temperature between 1700 degrees Celsius and about 2800 degrees Celsius to refine said melt of molten glass by expelling refining gas; and (d) withdrawing refined molten glass from said melt.