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H3BO3 Boric Acid Orthoboric Acid
USA and France
In manufacturing of fiberglass, borosilicate glass, and industrial ceramics, Optibor:
Optibor improves effectiveness of flame retardants and adhesives:
The boric acid in Optibor is needed across such diverse applications as nuclear energy and metallurgy:
When used in combination with a sodium borate (such as Neobor® or Dehybor® anhydrous borax), Optibor can adjust the sodium-to-boron ratio in glasses which require low sodium levels. This is important in borosilicate glass where boric oxide provides essential fluxing properties at low sodium and high alumina levels.
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Molecular weight: 61.83 g/mol
Specific gravity: 1.50 | Specific Gravity for Optibor Boric Acids Solutions (PDF)
Appearance: Free-flowing, white, crystal line granules or powder
Solubility: 5.46% boric acid by weight in saturated solution (water) at room temperature
Stability: Optibor is a stable crystalline product that does not change chemically under normal storage conditions. Wide fluctuations in temperature and humidity can cause recrystallization at particle contact points, resulting in caking. Care should be taken to avoid such fluctuations during product storage and to maintain the integrity of the packaging.
Bulk density: 55 lb/ft3 (881 kg/m3)
Angle of repose: 33°
Boric oxide, B2O3: 56.30%
Water of crystallization, H2O: 43.70%
Containers: Grades may be available in bulk, IBCs, or small bags
Optibor reduces the linear coefficient of expansion in glass when silica is replaced proportionately with boric acid, facilitating a thermal fit in ceramic glazes and heat resistance in borosilicate glass.
When heated above 212°F (100°C) in the open, Optibor gradually loses water, first changing to metaboric acid (HBO2), of which three monotropic forms exist. These metaboric acid forms can volatilize at >600°C during heating, leading to potential losses of boron emissions. Dehydration stops at the composition HBO2 unless the heating time is extended or the temperature raised above 302°F (150°C). On continued heating and at higher temperatures, all water is removed, leaving the anhydrous oxide B2O3—an amorphous glass that begins to flow at 842°F (450°C). The amorphous form of Optibor TG has no definite melting point, softening at about 617°F (325°C) and becoming fully fluid at about 932°F (500°C).
Aqueous solutions of Optibor are mildly acidic, the pH decreasing with increasing concentration. Optibor’s sieve specification is U.S. sieve No. 20, with a mesh size of 0.850 mm and a retained guarantee of ≤ 2.0%. Optibor forms boric oxide above ~300°C, which softens and begins to flow between 350°C and 500°C.
Optibor is ideally suited to bulk transfer. Optibor shows little tendency to cake, except after prolonged storage or severe wetting.
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