Glass ceramic and method for producing a glass ceramic

A method for producing a glass ceramic, the method comprising the steps of:

• providing a batch of raw materials;
• heating the batch of raw materials until a melt is obtained, the batch of raw materials being heated at least in a plurality of sections to a temperature above T3 which corresponds to a viscosity of a molten glass of 103 dPa*s;
• refining the melt, the melt being heated at least in a plurality of sections to a temperature above T2.5 which corresponds to a viscosity of the molten glass of 102.5 dPa*s;
• obtaining a refined glass which is configured for being ceramized to form a glass ceramic material;
• and
• ceramizing the refined glass to form the glass ceramic material, wherein at least one of the step of heating until the melt is obtained and the step of refining being performed with heating is by way of H2 and O2 combustion, the method being performed with an oxygen to fuel equivalence ratio λ which is lower than 1.05, 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=at least one of Na, K, Li, Mg, Ca, Sr, Ba and Zn is used, with a concentration of 0.5 wt.-% or less relating to a sum of all oxidized and reduced species of one each of the at least one refining agent, relative to a total mass of the batch of raw materials, wherein the at least one refining agent has a thermodynamic property of an at least 30% conversion of the at least one refining agent from a higher into a lower oxidation state according to a reaction of XnOm→XnOm-1+½O2 and XnOm→XnOm-2+O2 when the at least one refining agent has the formula XnOm, and/or of MnSO4→MnO+SO2+½O2 when the at least one refining agent has the formula MnSO4, in a melt of a same composition as the melt in the step of refining in a case of an oxygen partial pressure p(O2) of 1 bar and a temperature T2, wherein the temperature T2 corresponds to a viscosity of the molten glass of 102 dPa*s and an XnOm-1 to XnOm ratio or XnOm-2 to XnOm ratio in the refined glass which can be ceramized to form the glass ceramic material or the glass ceramic is at least 0.6.

A method for producing a glass ceramic, the method comprising the steps of:

• providing a batch of raw materials;
• heating the batch of raw materials until a melt is obtained, the batch of raw materials being heated at least in a plurality of sections to a temperature above T3 which corresponds to a viscosity of a molten glass of 103 dPa*s;
• refining the melt, the melt being heated at least in a plurality of sections to a temperature above T2.5 which corresponds to a viscosity of the molten glass of 102.5 dPa*s;
• obtaining a refined glass which is configured for being ceramized to form a glass ceramic material;
• and
• ceramizing the refined glass to form the glass ceramic material,
• wherein at least one of the step of heating until the melt is obtained and the step of refining is performed with heating by way of H2 and O2 combustion,
• wherein the step of heating until the melt is obtained is performed with an oxygen to fuel equivalence ratio λ>1.00;
• and the step of refining is performed with an oxygen to fuel equivalence ratio λ<1.05,
• wherein at least one refining agent at least one of of the formula XnOm, wherein n=1 or 2, m=2 or 5, and X=As, Sb, Sn, or Ce, and of the formula MnSO4, wherein n=1 or 2, and M=at least one of Na, K, Li, Mg, Ca, Sr, Ba and Zn is used, with a concentration of 0.5 wt.-% or less relating to a sum of all oxidized and reduced species of a respective one of the at least one refining agent, relative to a total mass of the batch of raw materials.