The Study On The Thermal Stability Of Nitrate Fertilizer In Aqueous Solution

In general, ammonium nitrate is stable and safe, but with temperature increasing, as well as impurities participation, ammonium nitrate will decompose and release heat, resulting in the burning or explosion. In view of the risk of ammonium nitrate a great deal of researches has been done at home and abroad. However, nitric phosphate containing ammonium nitrate are also dangerous, studies on the critical detonation temperature of them has been rarely reported.In this paper, thermal explosion theory is applied to study the thermal safety of nitric phosphate. An adiabatic heating calorimeter was used to study the thermal decomposition of nitric phosphate in aqueous solution at high temperatures. The critical detonation solution temperature of them is tested by changing the chroma of chloride ion, pH, grease, then arriving at the influence of chlorine ion, pH and grease on the thermal stability of nitric phosphate in aqueous solution, and exploring the reaction mechanism, in order to lay the further application of the theory basis and provide technical guidance.The present author has done experiments with nitric phosphate in aqueous solution containing 71% AN, which indicates that in acidic condition with the pH being constant, the bigger the chroma of the chlorine ions, the less stable the thermal nitric phosphate aqueous solution, and the lower the critical explosive temperature. Particularly speaking, in alkalescent or litmusless conditions, with the increase of temperature, chloride ions tend to restrain the decomposition of AN aqueous solution. And, in turn, at the presence of the chloride, vitriol is likely to promote the decomposition of AN aqueous solution. The experiment of nitric phosphate-potassium fertilizer in aqueous solution containing 40% AN indicated that a separate chloride ions can inhibit the decomposition of nitric phosphate-potassium fertilizer in aqueous solution, and the greater the concentration, the more obvious inhibition. However, separate grease can promote the decomposition of nitric phosphate-potassium fertilizer in aqueous solution. And as chloride ions and grease coexist in the system, when the chloride ions is constant, the content of grease is bigger, the thermal stability of nitric phosphate-potassium fertilizer in aqueous solution would be accelerate more; when the grease is existed, chloride ions can catalyze the decomposition of nitric phosphate-potassium fertilizer in aqueous system. These results were of important reference to the hazard control in the process of nitric phosphate -potassium fertilizer production and handling.