Study on the influencing factors of ultrafine spherical RDX during spray drying with low speed

Abstract

Cyclotrimethylene trinitramine (RDX, C3H6N6O6) with the size of 400 to 600 nm was prepared by low-speed spray-drying method. Meanwhile, the crystal morphology, particle size, crystal structure, thermal decomposition properties, and impact sensitivity properties of the raw materials of RDX and the prepared ultrafine spherical RDX were characterized by scanning electron microscope (SEM), laser particle size analyzer (LPSA), X-ray diffractometer (XRD), differential scanning calorimeter (DSC), and impact sensitivity instrument. The factors affecting experimental results were discussed; the size and morphology of RDX crystals were found to be affected by drying temperature, spray speed, and RDX mass fraction in solution. The optimal preparation conditions for the ultrafine spherical RDX were studied, and the results showed that the RDX particles with the best morphology and particle uniformity were prepared when the drying temperature was 90°C, spray speed was 1 ml/min, and the RDX mass fraction in solution was 4%. As a result, the activation energy (Ea) of the ultrafine spherical RDX was lower than that of raw RDX by 24.52 KJ·mol-1, and the characteristic drop (H50) of the ultrafine spherical RDX was higher by 35.3 cm.