Sodium fluorosilicate supplier Manufacturer in Chennai india

Sodium fluorosilicate is a compound with the chemical formula Na2[SiF6].Sodium fluorosilicate appears as white crystal, crystalline powder or colorless hexagonal crystals. It is odorless and tasteless. Its relative density is 2.68; it has moisture absorption capability. It can be dissolved in a solvent such as ethyl ether but insoluble in alcohol. The solubility in acid is greater than that in water. It can be decomposed in alkaline solution, generating sodium fluoride and silica. After searing (300 ℃), it is decomposed into sodium fluoride and silicon tetrafluoride. It is poisonous! 

In 25 degrees, the sodium fluorosilicate has its water solubility being 0.78%. Upon production, addition of an excess amount of sodium sulfate or sodium chloride can increase the concentration of sodium ions in the system, thereby increasing the solubility product of fluorine silicate and sodium ions, so that sodium fluoride can be subject to more complete precipitation. Sodium fluorosilicate is the byproduct in the production of calcium phosphate or the production of fluoride salt in aluminum factory. It generally appears as a white crystalline powder with low solubility in water (being 1% or less at room temperature), and the water solubility increases slightly with increasing temperature. The aqueous solution of sodium fluorosilicate is acidic (pH3).

 This is due to that its hydrolysis product contains hydrofluoric acid. Reduction of the acidicity of the solution facilitates the hydrolysis of sodium fluorosilicate. When pH is lower than 3.5-3.55, the hydrolysis reaction is stabilized. When the pH is equal to 4, the hydrolysis reaction rate is significant. When the pH value is equal to 8-8.5, the sodium fluorosilicate can be completely hydrolyzed to exhibit as silica gel and precipitated out. Therefore, when sodium fluorosilicate is added to the water glass, in addition to hardening effect of precipitation of silicon dioxide gel caused by the neutralization of the sodium hydroxide in the solution of water glass, the sodium fluorosilicate itself is also a source of silica gel.

Manufacturing

Sodium fluorosilicate is made by neutralizing fluorosilicic acid with sodium chloride or sodium sulfate.

Possible Application

It is used in some countries as additives for water fluoridation, opal glass raw material, ore refining, or other fluoride chemical (like sodium fluoride, magnesium silicofluoride, cryolite, aluminum fluoride) production.