The influence of the continuous crystallization process parameters on the crystal size distribution of struvite

The paper presents the results of the studies carried out on the crystallization process of magnesium ions precipitation in water with the use of ammonium dihydrogenphosphate NH4H2PO4 under alkaline conditions. The experiments were carried out in the continuous crystallizer with an internal circulation of suspension (T = 298 K). The influence of magnesium ions concentration in the raw material, pH, and the residence time on the mean size of magnesium ammonium phosphate hexahydrate crystals (Lm = 5.6 - 45.9 mm) were evaluated. The rates of struvite crystals growth (Gre = 1.0-10"9 - 9.6109 m/s) were evaluated from the crystal size distribution.