Process for preparing calcium fluoride from hexafluoro silicic acid and production of silicic acid gel or active silicic acid from said calcium fluoride

摘要

Disclosed is a process for the preparation of calcium fluoride comprising reacting hexafluoro silicic acid with calcium carbonate in the presence of sulfate or aluminum ions within a pH range of between about 2 and 6 and separating the calcium fluoride precipitate from the resulting aqueous silica sol.