Exploration of the Influence of High Rate Cooling Crystallization Parameters on the Preparation of Ammonium Perchlorate Crystals Using Taguchi's Method

Abstract

Preparation of fine ammonium perchlorate (AP) particles and thermal behaviour of it are known as the most important challenges in the crystallization and propellant sciences. We introduced an effective method of fine AP preparation named high rate cooling crystallization (HRC). This work presents application of Taguchi approach for optimizing the HRC method. In this study a set of experiments was designed according to the Taguchi L9 array. Experimental design was originated from four effective parameters containing; temperature, pressure, solvent type (water and ethanol) and anticaking agentsodium dodecyl sulfate (SDS). After preparation of fine AP particles average particle size (APS) was measured using laser mass spectrometry (LMS-30). APS, contribution, and the analysis of variance (ANOVA) were used to investigate performance factors affecting the operation condition. According to the data obtained, anti-caking agent and solvent type were represented the main effect on the preparation of micronized AP by using HRC method. Furthermore, the optimum condition in preparation of fine AP particles by using HRC method was ethanol solvent, 10atm pressure, 0.4 % SDS, and 60˚C temperature. Thermal behaviour of the optimized particles was investigated using TG/DSC analysis. Finety of the particles positively shifted the low temperature decomposition (LTD) region of fine optimized sample in comparison with coarse pure AP. Crystallinity of sample was confirmed by SEM and XRD analysis.

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