US 12,459,854 B2
Glass or glass ceramic as well as method for melting and refining glass or glass ceramic
Olaf Claußen, Undenheim (DE); Steffen Grün, Wallhausen (DE); Thomas Lifka, Mainz-Bretzenheim (DE); and André Schrepfer, Frankfurt (DE)
Assigned to Schott AG, Mainz (DE)
Filed by Schott AG, Mainz (DE)
Filed on Sep. 8, 2022, as Appl. No. 17/940,432.
Claims priority of application No. 10 2021 123 303.8 (DE), filed on Sep. 8, 2021.
Prior Publication US 2023/0074664 A1, Mar. 9, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. C03C 1/00 (2006.01); C03B 5/225 (2006.01); C03B 5/235 (2006.01); C03B 32/02 (2006.01); C03C 10/00 (2006.01)
CPC C03C 1/004 (2013.01) [C03B 5/225 (2013.01); C03B 5/2353 (2013.01); C03B 32/02 (2013.01); C03C 10/00 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for melting and/or refining glass, glass ceramic or glass which can be ceramized to form glass ceramic, the method comprising:
providing a batch of raw materials;
heating the batch until a melt of molten glass is obtained, wherein the batch is heated at least in sections to a temperature above T3 which corresponds to a viscosity of the molten glass of 103 dPa*s;
refining the melt, wherein the melt is heated at least in sections to a temperature above T2.5 which corresponds to a viscosity of the molten glass of 102.5 dPa*s, wherein refining of the melt comprises adjusting an oxygen partial pressure p(O2) which is reduced by at least 60% relative to an O2 saturation in the melt at temperature T3; and
obtaining a refined glass, a refined glass ceramic or a refined glass which can be ceramized to form glass ceramic;
wherein at least one refining agent of the formula XnOm, wherein n=1 or 2, m=2 or 5, and X=As, Sb, Sn, or Ce, and/or of the formula MnSO4, wherein n=1 or 2, and M=Na, K, Li, Mg, Ca, Sr, Ba and/or Zn is used with a concentration of 2 wt.-% or less relating to a sum of all oxidized and reduced species of the respective refining agent, relative to a total mass of the batch of raw materials, and
wherein the at least one refining agent of the formula XnOm and/or of the formula MnSO4 has the thermodynamic property that it has an at least 30% conversion from a higher into a lower oxidation state in a melt of the same composition as the melt in the refining step in the case of an oxygen partial pressure p(O2) of 1 bar and a temperature T2, according to the reaction of XnOm→XnOm-1+½O2 and/or XnOm→XnOm-2+O2, and/or according to the reaction of MnSO4→MnO+SO2+½O2, wherein temperature T2 corresponds to a viscosity of the molten glass of 102 dPa*s.