Preparation of ammonium dinitramide spherical particles with improved anti-hygroscopicity performance by a low-temperature safe process

Ammonium dinitramide (ADN) is a high-energy green oxidizer that holds significant promise for application in solid propellants with low signature; however, its practical application is limited by strong hygroscopicity. Preparing spherical particles is generally considered the prior method for ADN anti-hygroscopic modification and its scale-up preparation. Conventional techniques of preparing spherical ADN typically involve high-temperature melting processes, which entail considerable operational risks. In this study, ADN spherical particles with high sphericity, good powder properties, and adjustable particle size distribution were successfully prepared using a quasi-emulsion solvent diffusion spherical crystallization technology. The spherical products exhibit 47.6 % lower saturated moisture absorption ratio at 25 °C with a relative humidity of 53 % and 96.1 % lower caking strength after one week of storage under low-humidity conditions compared to the raw materials of ADN, which confirms the improved anti‐hygroscopic performance and anti-caking ability. More importantly, the operating temperature of this process can be substantially reduced to 25 °C, representing a 73.1 % decrease compared to the melting temperature of ADN (93 °C). This work presented a novel technique for the safe production of high-quality ADN spherical particles, laying a foundation for their potential application in solid propellants.