| abstract |
In the process for the preparation of dicalcium phosphate dihydrate with good fluorine compatibility and stability to hydrolysis, which, when used in toothpastes, causes the least possible thickening, by reacting calcium carbonate suspended in water with an aqueous solution of orthophosphoric acid, precipitating dimagnesium phosphate trihydrate as a stabilizer by converting aqueous ones Solutions of a magnesium salt and of orthophosphoric acid in the presence of a basic compound and subsequent addition of tetrasodium pyrophosphate as a further stabilizer to the reaction mixture and then filtering, drying and grinding the precipitate are added to the aqueous reaction mixture from 0.2 to 0.6% by weight of tetrasodium pyrophosphate, calculated on the dicalcium phosphate dihydrate precipitated in the reaction mixture. |