DICALCIUM PHOSPHATE DIHYDRATE FOR FLUORIDE DENTIFRICE COMPOSITIONS

The monofluorophosphate compatibility of dicalcium phosphate dihydrate can be improved in processes in which a slaked lime slurry is reacted with phosphoric acid to form a monocalcium phosphate solution to which is added magnesium oxide, additional lime slurry and pyrophosphoric acid with later removal of the dicalcium phosphate dihydrate. The improvement involved adding the magnesium oxide at 0.3%-2% and adding 0.1%--less than 0.5% of trimagnesium phosphate to the recovered dicalcium phosphate dihydrate.