Adjustment of the particle size of ADN-prills generated by the emulsion crystallization process

During the last years the high performance, low signature and environmental friendly oxidizer ammonium dinitramide (ADN) gained more and more acceptance for defence and space applications. But the application of ADN in solid propellant formulations leads to a requirement of spherical particles of at least two different particle sizes. Therefore a coarse particle size fraction in the range of 200-250 µm and medium particle size fraction in the range of 30-60 µm are demanded. A fine fraction of about 5 µm would be desirable. To achieve these requirements several process parameters of the emulsion crystallization process for ADN, the so-called ADN-Prilling process, were modified. By the variation of process fluids, additives, stirring energy and recrystallization behaviour it was possible to generate medium sized ADN-Prills with a mean particle size of 50 µm and coarse ADN-Prills with approx. 200 µm in technical scale.