Study On Crystal Shape And Granulation Controlling Of Explosives By Recrystallization

HMX and RDX are powerful explosives which are used around the world now. They are widely used to fabricate the explosive composite, solid rocket and gun propellant. The utility performance of the mixed explosives is great influenced by the characteristics of the based single crystals. The crystal characteristics can be improved by recrystallization process from the solutions. Therefore, it is important to research the recrystallization process of the explosive for engineering application.The mechanism of the influence on the particle shape is studied from the point of view of crystallization and crystal growth theory using recrystallization technology based on solvent-nonsolvent method. Furthermore, the impact factors on particle shape in the process of recrystallization, such as solvent, nonsolvent, temperature, active agent, stirring strength and feeding modes, are developed. The process for producing almost ball shape and even distribution of HMX/RDX particle with regular shape is developed. The grain size can be changed simply by controlling the adding rate and the amount of water or solution concentration.The experiment results are characterized by an optical microscope, SEM and the impact sensitivity experiment. The best condition for the formation of HMX particle ball shape is , 70℃,DMSO-solvent, methanol-nonsolvent, dextrin-surface active agent, 2000rpm-stirring strength. The impact test results indicate that the impact sensitivity of HMX as a function of granulation is linear. The impact sensitivity of HMX with 10μm grain size decreased by 24% compared with the original material.The crystal shape and inner quality of crystallized RDX are improved and the impact sensitivity is reduced. The best process condition is 70℃, DMSO-solvent, yellow methanol-nonsolvent, dextrin-surface active agent, 1000rpm-stirring strength. The impact test results indicate that the impact sensitivity decreased by 34% compared with the original material, when the granulation is 100~150μm.Most of the experiment in this dissertation is a kind of exploration research. The experiment results show that it is possible to make ideal particle shape by changing the recrystallization conditions. Some research results in this dissertation are of great guidance value to the study of the ball shape of simple substance explosive.