Study On The Spheroidization Process Of Solid Energetic Materials Nitrmine Compounds

Solid energetic material nitramine compounds have high coefficient of friction sensitivity because of its explosive nitroamine molecular structure,which is dangerous in the process of storage,transportation and use,also limits its widely application in industry.The crystal quality of the energetic materials mainly includes morphology,particle size,distribution and sphericity,which affect its thermal stability.In this dissertation,solvent-antisolvent crystallization method was used to prepare spherical particles,aims to reduce the sensitivity coefficient and improve the thermal stability.In this paper,two representative compounds of energetic materials(3,5-Dinitrobenzamide and 3,6-Dihydro-3-methyl-N-nitro-2H-l,3,5-oxadiazin-4-amine)were selected to explore the process of spherical crystallization.The effects of crystallization temperature,the volume ratio of solvent-antisolvent,surfactants and feeding modes on the morphology,particle size,sphericity and dispersion were systematically investigated.Optical microscope,scanning electron microscope(SEM),infrared spectroscopy(1R)and X-ray powder diffraction(XRD)were used to characterize the spherical samples.Through a large amount of experiments,its found that:the morphology of 3,5-Dinitrobenzamide crystal is nearly circular,with smooth surface,and the size distribution is 10μm～20μm(80%);the sphere-shaped 3,6-Dihydro-3-methyl-N-nitro-2H-1,3,5-oxadiazin-4-amine was prepared,with better dispersion and the size distribution is 5μm～10μm(75%).The results showed that the crystal particles prepared by this method with regular morphology,uniform particle size,smooth surface,high sphericity and well-dispersion.The outcome of the experiment showed that its possible to obtain the spherical crystal particles by changing the recrystallization conditions.Based on the experiments,the ellipsoidal CL-20 particles were obtained,and the size distribution is 8μm～15μm(60%).The particle size,dispersion and sphericity of CL-20 have been greatly improved.Some research results of this dissertation are of great guidance for the feasibility to prepare spherical crystal particles of CL-20.