Effect of the Impurity Ions on the Crystallization of Urea Phosphate

Abstract

Abstract In the present work, the influence of Al3+, Fe3+, SO42–, F–, Mg2+ on the crystallization of urea phosphate during the synthesis process of urea phosphate with phosphoric acid and urea was investigated. The crystallization time, the yield of urea phosphate, the purity of urea phosphate, crystal morphology, and the characterization of urea phosphate by Fourier transform infrared spectroscopy were studied. The experimental results show that the crystallization time of urea phosphate prolonged with the addition of impurities, the yield of urea phosphate all decreased with the increasing concentrations of Al3+, Mg2+, Fe3+ and SO42–, except F–. The impurities have no effect on the content of nitrogen and phosphorus in urea phosphate products. The Al3+, Fe3+, F– cause the irregular crystal morphology, while the crystal with the Mg2+, SO42– has a better dispersion, regular shape and high transparency. This study provides reliable and effective theoretical guidance for the synthesis process of urea phosphate by the wet process phosphoric acid.