GAS ANTISOLVENT RECRYSTALLIZATION OF RDX - FORMATION OF ULTRA-FINE PARTICLES OF A DIFFICULT-TO-COMMINUTE EXPLOSIVE

Recrystallization of cyclotrimethylenetrinitramine (RDX) using gas anti-solvents was investigated. RDX, an extremely sensitive high explosive, is difficult to recrystallize by conventional procedures in a form free of intragranular cavities. For example, solvent evaporation or liquid anti-solvent recrystallization methods may result in the inclusion of a liquid that causes voids when the explosive is subsequently dried. Since voids are detrimental to the performance of RDX-containing propellant and munition formulations, and since the only present means of reducing both the "void volume" and the particle size involves grinding, itself a difficult and dangerous operation, it is desirable to produce cavity-free RDX by direct recrystallization. GAS (Gas Anti-Solvent) Recrystallization has been shown to be an attractive process that can successfully produce void-free RDX in both currently desired sizes, viz., ultra-fine (<5 mum), and large (approximately 200 mum) particles.