Process for preparing crystalline DTPMP

The present invention relates crystallizates of pure aminoalkylenephosphonic DTPMP in three crystal modifications and a method for solids recovery crystalline DTPMP by a preferably single-stage crystallization from an aqueous product mixture containing DTPMP, the method comprising the following steps: a. Introducing seed nuclei containing DTPMP, in an aqueous crude product containing DTPMP with a total proportion in the range of 10 to 65 percent by mass, to a pulp density in the range of 1 to 25%, b. Entry kinetic energy in the aqueous crude product to give a crystalline product precipitates containing DTPMP as pure acid having a total content of at least 75 wt .-%, c. Separating the crystals from the aqueous crude product formed by sedimentation and / or filtration, so that DTPMP is obtained as a solid final product in the form of a crystallizate.