Detonation Mechanism And Explosion Property Of High Energy Emulaion Explosives Based On Hydrogen Storage Material

Emulsion explosive is the most widely used industrial explosive in China. However, traditional emulsion explosives exist low explosion power, pressure desensitization and safety problems, most high power emulsion explosives in the previous studies contain high explosives, perchlorates or high energy fuels (such as aluminum powders), which may increase explosive sensitivity; existing research related to "pressure desensitization" concentrated only on the desensitization mechanism and desensitization influencing factors of traditional emulsion explosives, but pressure desensitization problem of emulsion explosives still has not been solved effectively. In order to improve the performance of emulsion explosives, Hydrogen-containing composite emulsion explosives sensitized by MgH2was invented, and MgH2plays double roles as sensitizer and energetic material in emulsion explosives. The sensitization technology of hydrogen-containing composite emulsion explosives sensitized by MgH2developed in three stages, and they are hydrolysis sensitization, compound sensitization and dynamic sensitization. Hydrogen-containing composite emulsion explosives sensitized by hydrolysis sensitization and compound sensitization technology have been drived to maturity stage, while dynamic sensitization technology still needs further investigation.Our previous research showed that hydrogen storage material would release H2when compressed by shockwaves, and then the emulsion matrix was sensitized. This innovative sensitizing method not only enhances safety of emulsion explosive effectively, but also increases its charging density and explosion power. Detonation experiments, pressure desensitization experiments and scanning electron microscope experiments showed that:hydrogen-containing composite emulsion explosives sensitized by MgH2has advantages in work capability, brisance, detonation velocity and pressure resistance ability, compared with traditional emulsion explosives, the shock wave energy of hydrogen-containing composite emulsion explosives sensitized by hydrolysis sensitization technology of MgH2increased over30%, and to be worth notice, the brisance of hydrogen-containing composite emulsion explosive compound sensitized by coated MgH2reached the criterion of military explosives RDX (24.0mm), so its application prospect is much promising.In this research, the detonation characteristics, pressure desensitization mechanism and storage stability of hydrogen-containing composite emulsion explosives sensitized by MgH2with hydrolysis sensitization and compound sensitization technology are studied, and the dynamic sensitization technology has been initially verified. The specific research content as follows:The model of hotspot initiation of emulsion explosives was determined through literature research, and calculated the radius of hotspot and the order of magnitude of thermal that forming a hotspot needs, and theoretical derivation the relationship of the temperature variation of gasses in the sensitization bubble with physical size of sensitization bubble and constant-volume specific heat of gasses; detonation reaction model and mathematical model of emulsion explosives sensitized by glass microballoons are created, and the detonation pressure, explosion heat, detonation velocity, detonation reaction time and the length of detonation reaction zone are calculated, and the theoretical values are close to the experimental results. This method can be used as guidance for the mathematical model research of hydrogen containing composite emulsion explosives sensitized by MgH2.By using underwater explosion testing system and brisance experiment as well as detonation measuring experimental facility, detonation characteristics and mechanism of hydrogen-containing composite emulsion explosives sensitized by MgH2with hydrolysis sensitization technology are studied. Experimental results shows that: compared with emulsion explosives sensitized by glass microballoons, the shockwave total energy of hydrogen-containing composite emulsion explosives sensitized by MgH2with hydrolysis sensitization technology increased over32%, it brisance reaches18.58mm, and its detonation velocity gets to5000m/s; through experimental research and theory analysis, we find that the degree of detonation reaction of hydrogen-containing composite emulsion explosives sensitized by MgH2with hydrolysis sensitization technology is higher, and that is the most important reason for improving the detonation performance of emulsion explosives, what is more, the mechanism of hydrogen-containing composite emulsion explosives sensitized by MgH2with hydrolysis sensitization technology is defferent from traditional emulsion explosives, during its detonation reaction process, there are also existing hydrogen desorption reaction and of MgH2and hydrogen explosion reaction.The clad materials for MgH2and coating technology are chosen, and the coating effects are represented by SEM experiments and foaming restrain experiments, by using underwater explosion experiments, brisance experiments and detonation velocity measuring experiments, the dynamic sensitization effect and detonation performance of hydrogen containing emulsion explosives sensitized by MgH2with composite sensitization technology are studied. Experimental results show that, MgH2can be coated well with paraffin wax or stearic acid by sol-gel coating method; the brisance of hydrogen-containing composite emulsion explosives sensitized by hydrolysis sensitization technology of MgH2reaches24mm, which is close to the brisance of RDX. Detonation reliability and brisance experiments shows that the dynamic sensitization of coated MgH2really exists, but its effect still need to be improved, and "hotspot" is the major factor for influencing dynamic sensitization effect.In the pressure desensitization research of emulsion explosives, we designed a shockwave compression device to simulate the "pressure desensitization phenomenon" of emulsion explosive in the delay-action blasting. Experimental results show that MgH2can significantly improve the anti-pressure ability of emulsion explosives. Emulsion matrix appears demulsification phenomenon and sensitization bubbles are destroyed after compression, through comparative study,"hotspot" is the key factor for pressure desensitization, as for hydrogen containing composite emulsion explosives sensitized by MgH2, when the temperature and pressure reach a certain extent, MgH2will release H2and create new sensitization bubbles, so the anti-pressure ability of emulsion explosive is improved.The pictures of SEM and EDS shows that MgH2powders can be coated by paraffin wax film effectively, and each coated MgH2particle contains several MgH2particulate, and there are many nanoscale gaps on the paraffin wax film. Experiments show that paraffin wax film has good water resistance ability, but its anti-oxidation performance needs to be improved; underwater explosion experiments results shows that the detonation performance of hydrogen-containing composite emulsion explosives sensitized by MgH2changed only a little after5months, so its storage stability meet the requirement.