Studies on the Detonation Safety of Modified Ammonium Nitrate II. The Influence of Inorganic Chemical Fertilizer

Ammonium nitrate(AN) is modified by chemical fertilizer such as diammonium phosphate, monoammonium phosphate, ammonium sulfate, potassium sulfate and ammonium chloride, and then mixed with fuel oil and sawdust to make ANFO explosives. The explosives were initiated by No. 8 detonator. The thermal decomposition of the modified AN and ANFO explosives have been studied by isothermal and differential scanning calorimetry(DSC) in sealed capillary and anti-pressure sealed cell, respectively. It is found that the detonation of ANFO explosives can not be initiated with more than 40% monoammonium phosphate, 20% diammonium phosphate, 25% ammonium sulfate or 25% potassium sulfate in the modified AN. Detonation results are consistent with isothermal data, namely all the undetonated explosives possess the feature of decomposition percent less than 50% on heating at 370℃ for 1 minute. Chloride ion catalyzes the decomposition of AN, so the modified AN could be detonated with 30% ammonium chloride and decomposition percent is nearly 100% on heating at 370℃ for 1 minute.