Colored glass plate
View Patent ↗To provide a colored glass plate, which uses sodium sulfate (Na 2 SO 3 ) as a refining agent and which is capable of stably maintaining the mass percentage of divalent iron calculated as Fe 2 O 3 in the total iron calculated as Fe 2 O 3 at a high level, while suppressing development of an amber color that is derived from sodium sulfate. A colored glass plate made of alkali-containing silica glass containing elements of iron, tin and sulfur, wherein the percentage of the total sulfur calculated as SO 3 is at least 0.025% as represented by mass percentage based on oxides, the percentage of divalent iron calculated as Fe 2 O 3 in the total iron calculated as Fe 2 O 3 is from 60 to 80% as represented by mass percentage, and the percentage of divalent tin calculated as SnO 2 in the total tin calculated as SnO 2 is at least 0.1% as represented by mol percentage.
1. A colored glass plate made of alkali-containing silica glass comprising elements of iron, tin and sulfur, wherein the percentage of the total sulfur calculated as SO 3 is 0.025-0.065% as represented by mass percentage based on oxides, the percentage of divalent iron calculated as Fe 2 O 3 in the total iron calculated as Fe 2 O 3 is from 60 to 80% as represented by mass percentage, the content of Na 2 O is at least 0.5% as represented by mass percentage based on oxides, and the percentage of divalent tin calculated as SnO 2 in the total tin calculated as SnO 2 is at least 0.1% as represented by mol percentage, and wherein said colored glass plate is produced by a float process.
2. The colored glass plate according to claim 1 , which has an absorption coefficient of at most 1.00 cm −1 at a wavelength of 380 nm.
3. The colored glass plate according to claim 1 , wherein the percentage of divalent tin calculated as SnO 2 in the total tin calculated as SnO 2 is at least 3% and at most 40% as represented by mol percentage.
4. The colored glass plate according to claim 1 , which comprises, as represented by mass percentage based on the following oxides:
SiO 2 : from 30 to 80%,
Al 2 O 3 : from 0 to 30%,
B 2 O 3 : from 0 to 20%,
MgO: from 0 to 30%,
CaO: from 0 to 30%,
Na 2 O: from 0.5 to 50%,
K 2 O: From 0 to 50%,
Total iron calculated as Fe 2 O 3 : from 0.001 to 5%,
Total tin calculated as SnO 2 : from 0.001 to 5%.
5. The colored glass plate according to claim 1 , which comprises, as represented by mass percentage based on the following oxide:
Total sulfur calculated as SO 3 : from 0.055 to 0.065%.
6. The colored glass plate according to claim 1 , wherein the content of Na 2 O is from 1 to 30% as represented by mass percentage based on oxides.
7. The colored glass plate according to claim 1 , wherein the Te value of the colored glass plate is at most 50%.
8. The colored glass plate according to claim 1 , wherein the Sn-Redox of the colored glass plate is 0.1 to 50%.