Everett N Case

39432327, Mar 9, 1976

Mar 4, 1974

5/448153

Everett N. Case - Airville PA

Atlantic Richfield Company - Los Angeles CA

C01B 2516

423317

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.

40269957, May 31, 1977

Apr 12, 1976

5/676093

Everett N. Case - Airville PA

Atlantic Richfield Company - Los Angeles CA

C01B 2516

423321R

A process is provided for the defluorination of wet process phosphoric acid whereby hydrogen ion is removed, and the concentration of P. sub. 2 O. sub. 5 is adjusted with water, the calcium concentration, calculated as CaO, is adjusted by adding a source of calcium phosphate at temperatures of about 25. degree. C. to 75. degree. C. while maintaining a pH of about 2 or below to achieve substantially the maximum calcium content in aqueous solution and raising the temperature of the solution to about the boiling point to initiate the hydrolysis of silicofluoride and precipitate calcium fluoride which is separated, thereby producing a solution with an enhanced phosphoric acid content.