Sodium Fluoride

Brief overview

In the 19th century, research on fluoride and its occurrence in teeth and bones was carried out by physicians and chemists in Europe while the dental profession was still not organized as we know it today. The analytical methods of the time were quite limited and the results rather controversial.

Sodium fluoride is an ionic compound with the formula NaF. This colorless solid is the main source of the fluoride ion in diverse applications. NaF is less expensive and less hygroscopic than KF, but otherwise the potassium salt is more widely used.

Manufacturing Process

The method of preparing silica-free sodium fluoride comprising the steps of adding to fluosilicic acid at a temperature of about 50-90℃. An equivalent amount of ammonia, adjusting the pH to about 8-9 by further addition of ammonia, thereby producing a slurry of silica in an aqueous solution of ammonium fluoride, filtering said slurry to remove silica, cooling the filtrate to about room temperature, adding thereto sodium chloride equivalent to the ammonium fluoride whereby a slurry of solid sodium fluoride in aqueous ammonium chloride solution is formed, filtering the slurry to remove said solid sodium fluoride, admitting with the filtrate the filtrate from the ammonium chloride filtration step described below comprising an aqueous solution of ammonium chloride and sodium fluoride, evaporating the resulting mixed solution to yield a slurry of sodium fluoride and ammonium chloride in an aqueous solution saturated with respect to both salts, adding sufficient anhydrous ammonia to dissolve the ammonium chloride, thereby depressing the solubility of sodium fluoride, filtering off the sodium fluoride, evaporating the ammonia from the filtrate, thereby causing ammonium chloride to crystallize, filtering off the ammonium chloride, returning the filtrate to the filtrate from the first step above, and washing the sodium fluoride residues free of soluble salts, thereby obtaining substantially pure sodium fluoride.

Medical Industry

It is used in the treatment of osteoporosis. It improves bone strength and stimulates bone formation. It is also used as a tracer in medical imaging techniques.

Water treatment

Sodium Fluoride is added to drinking water and toothpastes for dental health. Fluoride salts are used to enhance the strength of teeth by the formation of fluorapatite, a naturally occurring component of tooth enamel.

Other Applications
It is used as a cleaning agent, stomach poison for plant-feeding insects, chemical synthesis. Sodium fluoride is used in the manufacturing of steel and aluminum metals. It's also used as a metal surface treatment and cleaning agent, for glass frosting, as a wood preservative, and for pH adjustment in industrial textile processing.