Process for preparing calcium fluoride from hexafluoro silicic acid and production of silicic acid gel or active silicic acid from said calcium fluoride
AssigneeKali-Chemie Aktiengesellschaft
InventorsWilfried Becher, Joachim Massonne
Life of this patent
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Abstract
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.
Claims13
A process for the production of calcium fluoride, comprising the steps of reacting hexafluorosilicic acid having a concentration of between 10 to about 40% by weight with calcium carbonate in the presence of aluminum ion in a molar ratio of aluminum to hexafluorosilicic acid of between about 1:7 and 1:100 at a pH between about 2 and 6, whereby the aluminum ion provides for the formation of an easily separable mixture of calcium fluoride precipitate and aqueous silica sol, and separating said calcium fluoride precipitate from said silica sol.
Dependencies are inferred from the claim text.