Everett N. Case - Airville PA
Atlantic Richfield Company - Los Angeles CA
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.