Process for producing sodium fluoride from sodium silicofluoride

摘要

A process for producing sodium fluoride from sodium silicofluoride in which sodium silicofluoride is added to an ammonium fluoride solution for double decomposition reaction to obtain a slurry containing sodium fluoride as crystals and ammonium silicofluoride in dissolved form, and the solution from which the sodium fluoride crystals have been removed is added with ammonia to decompose the ammonium silicofluoride into silica and ammonium fluoride. The ammonium fluoride obtained by the decomposition is recycled to the double decomposition step. Alternatively, the ammonium fluoride is reacted with a sodium salt for recovery as sodium fluoride.