Research On Theory Of Self-sensitization Of Expanded Ammonium Nitrate And Physical Properties Of Its Explosive And Modification

In this dissertation, the pore diameter distribution, pore volume, cumulative pore area and pore volume, extended surface area, specific surface area and adsorbability of expanded ammonium nitrate and powdery ammonium nitrate have been measured respectively. It is shown from measurement that the reason of expanded ammonium nitrate possessing higher oil adsorbability and lower oil effusion than that of powdery ammonium nitrate lies in its micro-porous structure. It is also shown that micro-pore couldn't be destroyed by crush. Based on theory of hot spot and thermal explosion, and combined the measurement results and influences of expansion process, randomicity of hot spot formation in expanded ammonium nitrate and its explosives is proposed. Sensitivity to shock 'wave of expanded ammonium nitrate fuel oil explosives have been tested, it is concluded that expanded ammonium nitrate fuel oil explosives have higher shock wave sensitivity, expanded ammonium nitrate has larger specific surface area and porousity met the shock initiation mechanism requirement. It is proven from these measurements that the theory of self-sensitization of ammonium nitrate is correct.Based on double spectra line temperature measurement method, a set of optical fiber temperature measurement system has been established. Detonation temperature of expanded ammonium nitrate explosive, AN-TNT type explosive, emulsion explosive and powdery emulsion explosive have been measured real time and continuously, using this system, and temperature-time distribution results are obtained. It is concluded that expanded ammonium nitrate explosive possess higher detonation temperature. Formulas of rock and permissible expanded ammonium nitrate explosive are determined by annual neural net method, according to temperature measurement results. Detonation heat of expanded ammonium nitrate explosive also has been tested by adiabatic method. It is shown that expanded ammonium nitrate explosive has higher detonation heat. From two energy index, namely, detonation temperature and detonation heat, it is proved that self-sensitization theory is reasonable and right.Adiabatic thermal decomposition of expanded ammonium nitrate and its explosive, AN-TNT type explosive, emulsion explosive and powdery emulsion explosive have been investigated using accelerating rate calorimetry. Kinetic parameters, such as activation energy, pre-exponential factor and reaction order and reaction heat are calculated using reaction rate method and mechanism function method. Thermal safety of expanded ammonium nitrate and its explosive, and other type explosive have been evaluated according to temperature, pressure and temperature rise rate in thermal decomposition. It is revealed that expanded ammonium nitrate and its explosive, and other type explosive is thermal stable.To the question of poor fluidity of expanded ammonium nitrate explosive, three methods are introduced to solve this problem. One is non-explosion powder materials with better fluidity are added in explosive, another is regulating the oil composition and formula, last method is that diesel is substituted by solid combustible agent with higher combustion heat value. Satisfactory and plenty results are obtained, and estimation methods of fluidity are proposed in this dissertation. In order to improve charge density of expanded ammonium nitrate explosive, crystal modification agents are used in expansion process, and part of expanded ammonium nitrate are replaced by powder ammonium nitrate, two methods are feasible and can improve charge density.Fibrosis method, oxidizer salts soakage method and coating catalystic method are introduced to modify sawdust, and influences of modified sawdust on explosion properties are also investigated, three kinds of modified sawdust are feasible in improving explosion properties of expanded ammonium nitrate explosive. Surface characteristic parameters of fibrosis sawdust, oxidizer salts sawdust and ordinary sawdust of different particle size are measured, it is revealedthat the mechanism o...