The copper influence on the thermal decomposition kinetics of complex chloride-containing ammonium nitrate-based fertilizers

The study results of the copper influence on the thermal decomposition kinetics of complex nitrogen–phosphorus–potassium chloride-containing ammonium nitrate-based fertilizers with different molar ratios of ammonia to phosphoric acid by thermogravimetry and differential scanning calorimetry are presented. Measurements are taken in non-isothermal conditions at constant heating rates in the temperature range of 20–250 °C. Calculations of the decomposition rate and the heat release rate depending on the extent of decomposition under isothermal conditions are performed by the Friedman isoconversional method. Based on the conducted research results, conclusions about the causes of the copper influence in a complex fertilizer composition on the thermal decomposition kinetics are made. It is shown that in the presence of copper in chloride-containing ammonium nitrate-based fertilizers the decomposition and heat release rates, and the magnitude of exothermic decomposition effect increase. It was also found that copper compounds do not affect the initial decomposition stage.