Effect of Impurities on Thermal Decomposition Kinetics of Mineral Fertilizers Based on (NH4)2HPO4 in Self-Generated Atmosphere

Abstract

The effect of impurities on the thermal decomposition kinetics of mineral fertilizers based on (NH₄)₂HPO₄ in self-generated atmosphere was studied by the methods of thermogravimetry and differential thermal analysis. Results are presented of isothermal measurements made in the temperature range 100–110°C. An analysis of the experimental data made it possible to suggest reaction models of the decomposition and to reveal a dependence of the activation energy on the degree of decomposition. A strong deviation of the temperature dependence of rate constants from the Arrhenius law was observed. Conclusions were made on the basis of the study about the influence exerted by impurities on the thermal decomposition of mineral fertilizers based on (NH₄)₂HPO₄ in the self-generated atmosphere and reasons for the deviation from the Arrhenius law.