Infuence of Iron Ion on Thermal Behavior of Ammonium Nitrate and Emulsion Explosives

The infuence of ferric nitrate on the thermal stability of ammonium nitrate and emulsion matrix were used to study with Accelerating Rate Calorimeter (ARC) and constant temperature thermal decomposition experiment in this paper. It is shown that ferric nitrate has signifcant catalytic property to the ammonium nitrate and emulsion matrix, which decrease the initial decomposition temperature of ammonium nitrate by 60.16 C and emulsion matrix by 30.33 C. The results of the infuence of ferric nitrate on catalysis of ammonium nitrate using ARC and constant temperature thermal decomposition experiment are the same. The most probable mechanism function, activation energy and the preexponential factor of ammonium nitrate with ferric nitrate were determined to be f(α) = 1-α, E = 195.41 kJ/mol, A = 2.08×1019 s-1. The kinetics of ammonium nitrate decomposition can be used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of ferric nitrate, based on the Frank-Kamenetskii model of thermal explosion. Furthermore, as the iron-plate experiment shows, ferric nitrate can signifcantly reduce the critical temperature of emulsion matrix decomposition. Once the ferric nitrate interfuses in the ammonium nitrate and emulsion matrix, the thermal stability of ammonium nitrate and emulsion matrix is decreasing.