Process for the defluorination of dilute fluorine containing aqueous acid solutions
AssigneeAtlantic Richfield Company
InventorEverett N. Case
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Abstract
A process is provided whereby dilute aqueous phosphatic acid solutions of 2 to 3 percent or less and containing generally less than 1 percent fluorine are substantially quantitatively defluorinated without loss of the phosphorous or acid values of the water and with a net production of H+ ions from the contained SiF.sub.6.sup.= ions.
Claims7
In a process for the defluorination of a dilute fluorine-containing aqueous phosphatic acid solution derived from the process water of a wet process phosphoric acid plant said solution containing less than 3 percent P.sub.2 O.sub.5 the improvement which comprises heating the solution to a temperature in the range of about 80.degree.C. -100.degree.C. in the presence of a solid source of Ca.sup.+.sup.+ ions selected from the group consisting of calcium sulfates, calcium phosphates and phosphate rock, for a length of time sufficient to precipitate calcium fluoride from said aqueous acid solution and thereby increase the net available H.sup.+ ions associated with the original phosphatic solution.
Dependencies are inferred from the claim text.