Research Of Controling The Morphology And Particle Size Of HMX Crystals Material

HMX is an elemental high-energy explosive.HMX has been widely used in national defense,military and other fields since it was found and separation from RDX in 1941.Many scientists have been interesting in HMX and tried to keep it more more effective and safety in the 70 years.In this paper,for improving the purity,crystal morphology and effectiveness of HMX products,We research the crystallization,separation,and purification process of HMX with the theoretical and experimental method.This paper is divided into six chapters,the main content of each chapter is introduced as below.Chapter 1:The application,importance and existing defects of HMX are introduced and the importance of the study on crystallization process of HMX is shown.The main research direction of the crystal control study and research progress in these research directions are introduced.The research direction,research contents and achievements of the paper are also shown.Chapter 2:We studied the HMX crystals morphology.On the basis of the single crystal data of HMX,the HMX crystal structure,crystal system,and the crystal cell parameters,the crystallography data such as space group are known.The HMX crystal morphology prediction in a vacuum is study,Using the theoretical model(BFDH model and AE model)by the software Materials Studio.Then,HMX predict crystal morphology with the effect of the different organic solvents is studied through simulation calculation.With the solvent evaporation method and falling temperature method in the crystallization test,the HMX crystal obtained from the dimethyl formamide,dimethyl sulfoxide,acetone,cyclohexanone,propylene carbonate solvent are explored.By comparing the HMX crystal morphology predicted in Materials studio software and HMX crystal morphology obtained in experiment,the effect of solvent on HMX crystal morphology is researched.Chapter 3:The HMX crystal morphology grown in the mixed solvent and the solvent-nonsolvent system have been predicted by the method and theory used in the second chapter.The mixed solvent are propylene carbonate/acetone,cyclohexanone/acetone,dimethyl formamide/acetone,dimethyl sulfoxide/acetone and butyrolactone/acetone.The solvent-nonsolvent system are propylene carbonate/water,dimethyl formamide/water,butyrolactone/water,acetone/water,propylene carbonate/ethanol,dimethyl formamide/ethanol,butyrolactone/ethanol and cyclohexanone/ethanol.Then,the HMX crystal,grown in the solvent mentioned above,are obtained by the experiment of the solvent nonsolvent method and evaporation method.Through comparing the crystal morphology,The HMX crystal morphology on the effect of the mixed solvent and solvent-nonsolvent are explored.Chapter 4:The thermodynamics data in the crystallization process of the HMX crystal are examined.First of all,the solubility and the supersaturation of HMX crystal in different temperature and different solvents is determined by the static method,such as dimethyl formamide,dimethyl sulfoxide,acetone,cyclohexanone,propylene carbonate solvent.The solubility and the supersaturation of HMX crystal are calculated with different equations and the fitting data are basically reasonable.The solubility curve and the supersaturation curve of HMX crystal in different solvent are made by using fitting data of the solubility and the supersaturation of HMX crystal.The solid-liquid surface tension and surface entropy factor are calculated.The growth mechanisms of HMX crystal grown in different solvent are determined by the surface entropy factor data.Chapter 5:The reaction kinetics of the crystallization process of the HMX crystal are studed by the batch dynamic method,and the crystal grain size data are analysed by the method of moments.The nucleation rate and growth rate in the crystallization process of HMX crystals are obtained by the nucleation theory relating the induction time and the supersaturation.The nucleation mechanism of HMX crystal is analysed.Chapter 6:We study the influence factor of HMX crystals in the crystallization process.In the above 5 chapters,We have studied the HMX crystal morphology grown in different organic solvents,mixed solvents and solvent-nonsolvent systems,thermodynamics of the crystallization process and reaction kinetics of the crystallization process of HMX crystals.Now,we examine the other various influence factors in the crystallization experiment of HMX crystals,such as temperature,crystallization method,additives,stirring speed and so on.Considering the impact test of various factors,the optimum operation conditions in the crystallization process of HMX crystals is determined.The perfect HMX crystal morphology and particle size distribution can improve the quality of the HMX products and provide the basis for further industrialization of HMX products.