Study on crystallization behavior of magnesium ammonium phosphate

摘要

In order to study crystallization behavior of magnesium ammonium phosphate(MAP) under different conditions, the crystals were obtained by chemical precipitation in de-ionic water with NH4Cl, MgCl2 and Na2HPO4.Through the XRD and SEM methods, it is found that MAP were transmuted into Mg3(PO4)2 when pH from 9 to 12. In the condition of pH=9, Mg3(PO4)2 were transmuted into MAP with the increasing of N dosing ratios, the crystals were MAP with the increasing of Mg dosing ratios, the amorphous matter were transmuted into MAP with the increasing of P dosing ratios, and the shape of crystals show definite difference at different ion dosing ratios. The composition of crystals was almost invariable when reactive temperature, crystallization time and mixture speed changed in experimental range, but which affected the shape of crystals.