The precipitation of calcium hydrogen phosphate, CaHPO_4.2H_2O (DCP), was studied in a batch crystallizer, with both analytical and commercial grade reagents. The solubilities of DCP in water, between 5 and 40 °C, were measured. The shape, size and agglomeration of the crystals, obtained under different operating conditions, were investigated by Scanning Electron Microscopy (SEM), and by Laser Light Scattering. The influence of fluoride ions on the size, form and agglomeration degree of the DCP crystals was studied, and, even for concentrations as low as 10 ppm, a strong effect on the form and agglomeration of the crystals is observed.
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