CRYSTALLIZATION OF SPHERICAL AMMONIUM DINITRAMIDE (AND) PARTICLES FROM EMULSIONS

摘要

The process described aims to produce spherical ammonium dinitramide (ADN) particles of different sizes with a narrow particle size distribution. ADN has a melting point of v_S ? 92 °C. The crystallization process presented in this paper comprises two stages. In the first stage, molten ADN is dispersed in a continuous phase in which ADN is insoluble. The droplet size produced can be controlled by varying the amount of mechanical energy supplied to the two-phase system. In addition to discussing the influence of the different process parameters, such as dispersion rate, dispersion power, emulsification time, etc., this paper also covers the influence of emulsifying agents and the rheological behavior of the continuous phase. In the second stage of the process, crystallization of the emulsified ADN droplets to spherical, solid particles is brought about by reducing the temperature of the system. The process described enables production of spherical ammonium dinitramide particles with mean sizes from 10 μm to 600 μm. The product quality of the crystallized ADN, which is also discussed in this paper, was determined using various analysis techniques, including differential scanning calorimetry (DSC), IR spectroscopy, ion chromatography and laser light diffraction.