FIELD OF THE INVENTION
[0001] The present invention relates to the field of glass production, specifically opal glass
and a novel composition for opal glass production in furnace made of refractories lining,
aiming to eliminate the harmful effects of traditional components while reducing the
5 corrosion in the refractories and thereby enhancing the life of refractories.
We claim:
1. An environmental friendly spontaneous opal glass demonstrating a
5 dense, milky-white appearance having a level of opacity in excess of 80% , a
softening point less than 760° C but in excess of 725° C, wherein sphericallyshaped, glassy droplets constitute the opal phase containing the following
composition essentially in terms of weight percent on the oxide basis as
calculated from the batch of, 57-71% SiO2, 10-18 % Na2 O, 1.25 - 5.75% BaO,
10 1.8-6.2% Al2 O3, 2-9% B2 O3, 1.5- 7.1% CaO, 0.5-2.5% ZnO , and 2.5-6.5% P2
O5, wherein, the total of the weight quantities of the ingredients amounting to
100%, having said that the opal glass composition is free from Fluorine (F) and
compounds containing (F) and is opalized as a result of phase separation during
formation or with a post-formation heat treatment, in the temperature range of
50-300°C, and a density of at least 2.4 g/cm3 15 .
2. An environmental friendly spontaneous opal glass set forth in claim 1,
characterized in that it has the following composition essentially in terms of
weight percent on the oxide basis as calculated from the batch of, 60-69% SiO2,
12-17 % Na2 O, 2.1 - 4.75% BaO, 2.5-5.1% Al2 O3, 4-8% B2 O3, 2.1- 5.8% CaO,
20 0.7-2.2% ZnO , and 3.5-6.2% P2 O5, wherein, the total of the weight quantities of
the ingredients amounting to 100%.
3. An environmental friendly spontaneous opal glass set forth in claim 1,
wherein the level of opacity is greater than 83%.
4. An environmental friendly spontaneous opal glass set forth in claim 1,
25 wherein the composition ensures to achieve opacity with minimum u