Preparation Of Superfine Ammonium Perchlorate In Mixed Solvent System

Ammonium perchlorate (AP) is commonly used in solid propellant oxidizer, accounted for 70%-80% of solid propellant mass fraction. Therefore, the morphology and particle size of AP is closely related to the performance of solid propellant. The solvent recrystallization method is a kind of important method of preparing the AP, solvent had a great influence on the morphology and particle size of AP. At present, the anti-solvent recrystallization preparation of AP mostly use the single solvent. The research using mixed solvent preparation of AP is less. In this thesis, AP of different morphology and particle size prepared with acetone and alcohols (including methanol, ethanol, isopropanol and ethylene glycol), DMF and alcohols, DMAC and alcohol as mixed solvent and ethyl acetate as anti-solvent. The main contents and results are as follows:(1) The study of mixed solvent type. Different morphology and particle size of AP were prepared with acetone/alcohols, DMF/alcohols and DMAC/alcohols. The results show that the solvent type on the morphology and particle size of AP effects obviously. After adding alcohol, particle size of AP prepared by acetone/alcohols, DMF/alcohols, DMAC/alcohols mixture solvent compared with single acetone, DMF, and DMAC solvent decreased significantly. The structures of AP productions with acetone/alcohol are similar to the structures of AP productions with single alcohol solvent. In the DMF/alcohols and DMAC/alcohols mixed solvent, structures of AP are more effected by DMF and DMAC.(2)The study of the two kinds of solvent volume ratio of the mixed solvent. Choosing acetone/isopropanol, DMF/isopropanol and DMAC/isopropanol adjust the volume ratio was prepared with different morphology and particle size of AP. The results show that acetone/alcohols, DMF/alcohols and DMAC/alcohols mixed system, the rising proportion of one kind of solvent, the corresponding impact on the AP particle size and morphology is increased.(3)The study of mixed solvent and anti-solvent volume ratio. Choosing acetone/isopropanol, DMF/isopropyl alcohol and DMAC/isopropanol, explore mixed solvent and anti-solvent volume ratio on the AP particle size and morphology. Results show that the acetone/alcohols, DMF/alcohols and DMAC/alcohols mixed system, with the loss of the mixed solvent and anti-solvent volume ratio, the AP particle size decreases. After mixed solvent and the anti-solvent volume ratio reaching a certain proportion, the decreasing trend are easing.(4) Research of ultrasonic stirring. Choosing acetone/alcohol, DMF/alcohol and DMAC/alcohol system to explore the ultrasonic stirring of mixed solvent of AP particle size and morphology. Results show that acetone/alcohol, DMF/alcohol, DMAC/alcohol three kinds of hybrid system under the condition of ultrasonic, due to acoustic cavitation generated by ultrasonic stirring and ultrasonic influence the nucleation and growth of the crystal. Crystal surface tension decreases, and the morphology of AP become spherical.