Method of making clear glass composition
View Patent ↗A technique of manufacturing glass having fairly clear color and/or high visible transmission is provided. In certain example embodiments of this invention, it has surprisingly been found that by using carbon-containing compound(s) including C x H y O z .mH 2 O, excellent melting and refining can be achieved in the manufacture of glass, and not as much ferrous iron is formed compared to the use of elemental carbon as a refining agent. Such compound(s) are especially advantageous when highly transparent clear glass is desired, in that less ferrous iron is formed and thus transmittance and coloration can be improved.
1. A method of making a glass comprising:
Ingredient
wt. %
SiO 2
67-75%
Na 2 O
10-20%
CaO
5-15%
total iron (expressed as Fe 2 O 3 )
0.01 to 0.30%
wherein the glass has visible transmission of at least about 90%, a transmissive a* color value of from about −1.5 to +1.0, and a transmissive b* color value of from about −1.0 to +1.5, wherein the method comprises:
in a melt, using as a refining aide at least one carbon-containing compound comprising citric acid when making the glass, and wherein the refining aide further includes crystalline water to improve wetting.
2. A method of making a glass comprising:
Ingredient
wt. %
SiO 2
67-75%
Na 2 O
10-20%
CaO
5-15%
total iron (expressed as Fe 2 O 3 )
0.01 to 0.30%
wherein the glass has visible transmission of at least about 90%, a transmissive a* color value of from about −1.5 to +1.0, and a transmissive b* color value of from about −1.0 to +1.5, wherein the method comprises:
in a melt, using as a refining aide at least one carbon-containing compound comprising one or more of citric acid or citric acid monohydrate making the glass, and wherein the refining aide further includes crystalline water to improve wetting.
3. The method of claim 1 , wherein the glass comprises:
total iron (expressed as Fe 2 O 3 )
0.02 to 0.20%
erbium oxide
0.02 to 0.20%.
4. The method of claim 1 , wherein the glass comprises:
total iron (expressed as Fe 2 O 3 )
0.054 to 0.20%
erbium oxide
0.02 to 0.15%.
5. The method of claim 1 , wherein the glass comprises:
total iron (expressed as Fe 2 O 3 )
0.06 to 0.10%
erbium oxide
0.03 to 0.10%.
6. The method of claim 1 , wherein the glass has a redox value (FeO/Fe 2 O 3 ) no greater than 0.15.
7. The method of claim 1 , wherein the glass has a redox value (FeO/Fe 2 O 3 ) no greater than 0.10.
8. The method of claim 1 , wherein the glass has a transmissive a* color value of −1.0 to +1.0, and a transmissive b* color value of −0.7 to +1.0.
9. The method of claim 1 , wherein the glass has a transmissive a* color value of −0.8 to +0.5.
10. The method of claim 1 , wherein the glass comprises from 0-5% MgO, from 0-5% K 2 O and from 0-5% Al 2 O 3 .
11. A method of making a glass comprising:
Ingredient
wt. %
SiO 2
67-75%
Na 2 O
10-20%
CaO
5-15%
total iron (expressed as Fe 2 O 3 )
0.01 to 0.15%
wherein the glass has visible transmission of at least about 85%, a transmissive a* color value of from about −1.5 to +1.0, and a transmissive b* color value of from about −1.0 to +1.5, wherein the method comprises:
in a melt, using as a refining agent at least one carbon-containing compound comprising citric acid when making the glass.
12. A method of making a glass comprising:
Ingredient
wt. %
SiO 2
67-75%
Na 2 O
10-20%
CaO
5-15%
total iron (expressed as Fe 2 O 3 )
0.01 to 0.15%
wherein the glass has visible transmission of at least about 85%, a transmissive a* color value of from about −1.5 to +1.0, and a transmissive b* color value of from about −1.0 to +1.5, wherein the method comprises:
in a melt, using as a refining agent at least one carbon-containing compound comprising one or more of citric acid or citric acid monohydrate making the glass.
13. The method of claim 2 , wherein the glass comprises:
total iron (expressed as Fe 2 O 3 )
0.02 to 0.20%
erbium oxide
0.02 to 0.20%.
14. The method of claim 2 , wherein the glass comprises:
total iron (expressed as Fe 2 O 3 )
0.054 to 0.20%
erbium oxide
0.02 to 0.15%.
15. The method of claim 2 , wherein the glass has a redox value (FeO/Fe 2 O 3 ) no greater than 0.15.
16. The method of claim 2 , wherein the glass has a redox value (FeO/Fe 2 O 3 ) no greater than 0.10.
17. The method of claim 2 , wherein the glass has a transmissive a* color value of −1.0 to +1.0, and a transmissive b* color value of −0.7 to +1.0.
18. The method of claim 2 , wherein the glass has a transmissive a* color value of −0.8 to +0.5.