Solvent–Solvent Cooling Crystallization: An Effective Method to Control the Morphology and Size of Ammonium Perchlorate Crystals

Abstract Controlling ammonium perchlorate crystals with desired properties is still a challenge in industrial crystallization. In this work, two different cooling crystallization methods, namely solvent–solvent cooling crystallization and batch cooling crystallization, are compared to prepare ammonium perchlorate crystals with tunable shapes and sizes. The influences of crystallization parameters such as cooling pattern, cooling rate, stirring rate, feed rate, and solution concentration on the morphology and size of ammonium perchlorate particles are studied. The results indicate that solvent–solvent cooling crystallization makes it easier to control the supersaturation of the crystallization system than bath cooling crystallization, resulting in a more uniform morphology of the ammonium perchlorate crystals prepared by the solvent–solvent cooling crystallization. In addition, by adjusting the crystallization conditions, the shape of ammonium perchlorate crystals can be tailored as long rectangle, tabular, spherical, platy, bipyramid, and high‐index faced polyhedron shaped, the mean size of which can be controlled from 43.9 to 191.9 µm. Moreover, the proposed crystallization method provides a promising strategy for the continuous production of ammonium perchlorate crystals in industry; it is also a reference for the crystallization of other materials in crystal engineering.