Polycondensation of urea phosphate to ammonium polyphosphate

Ammonium polyphosphate of average chain length n = 2.5 - 3.0 can be obtained through the polycondensation of urea phosphate at a temperature of 140 - 160°C. The phosphates fraction in the product amounts to about 90% whereby it has a high capacity to chelate fertilizer microelements. The effect of such parameters as temperature and reaction time on the composition and kinetics of the reaction was assessed by means of derivatographic and model tests.