Explosion characteristics and thermal safety of low detonation velocity emulsion explosives containing coal-based solid waste fly ash microspheres

In this paper, the microspheres in flying-ash are used as sensitizer and inert additive to prepare the low detonation velocity emulsion explosives. The detonation velocity and the parameters of explosive shock wave in the air of emulsion explosives were measured by the probe method, the lead column compression method and the air explosion method, respectively. The safety of emulsion explosives was tested by the storage life experiment and thermal analysis experiment. The experimental results show that the detonation velocity, the brisance, the peak pressure, the positive impulse and the positive pressure action time of shock wave of emulsion explosives increased first and then decreased with the increase of the content of flying-ash microspheres. When the content of flying-ash microspheres was 15%, the detonation performance of emulsion explosive was the best, and when the content of flying-ash microspheres was 45% , the detonation velocity of the explosive decreased obviously. Meanwhile, the detonation velocity ranged from 2191 to 2312 m/s, which can satisfy the condition of using explosive for explosive welding. In addition, it is found that the detonation performance of emulsion explosives with D₅₀=79 μm flying-ash microspheres was higher than those of flying-ash microspheres with D₅₀=116 and 47 μm. The storage life and thermal analysis results indicate that the storage life of low detonation velocity emulsion explosives with flying-ash microspheres is significantly better than that of traditional low detonation velocity emulsion explosive with clay particles, the activation energy of thermal decomposition of the emulsion explosive with 15% flying-ash microspheres was only 0.3% higher than that of emulsion matrix. The results also show that the addition of flying-ash microspheres has no obvious effect on the thermal stability of the emulsion matrix. The research results have important reference value for green resource disposal of coal-based solid waste and formulation design of the low detonation velocity emulsion explosive.