A direct method of preparing ultra-fine RDX crystals

A new method for the direct preparation of ultra-fine RDX crystals was proposed. HA and HNO₃ reacted with each other to form a solution of RDX in HNO₃, then it was diluted with water in a range of temperature from 0∼50°C, the desired ultra-fine RDX crystals were precipitated directly by controlling the process conditions. 50 g scale experiments were conducted in the laboratory. Special attention was paid to study of the process conditions which affected the granularity of the ultra-fine RDX crystals such as the crystallization temperature, stirring speed, the amount and concentration of the HNO₃ solution, and the amount of dilution water etc. The ultra-fine RDX crystals with 5∼10 μm median particle diameter were prepared by this method. The amount of residue acid of the ultra-fine RDX products was less than 0. 02%.