Ammonium perchlorate is one of the most important and applicable oxidizers used in solid propellants. Also, the morphology of ammonium perchlorate particles is an effective parameter in the production of propellants. In the current research, the preparation of ammonium perchlorate using the cooling crystallization method was studied. Four parameters including the rate of cooling, mixing patterns, agitator speed, and surfactant were considered in cooling crystallization of ammonium perchlorate. Nine tests were carried out based on the Taguchi experimental design method. The morphology of the obtained crystals was analyzed by optical microscope and MIP 4 student software. The size distribution of the particles was modeled using the Rosin‐Rammler method. Obtained results illustrated that the surfactant had the most effect with the value of 70.7 % and the agitator speed, flow pattern, and cooling rate had fewer effects on the morphology with the values of 25.8 %, 2.9 %, and 0.2 %, respectively. The optimal amount of sphericity obtained by the Taguchi method was 0.77 which was verified by the experimental result of 0.76. The roundness and aspect ratio values for the optimal crystal were 0.79 and 1.40 respectively. Applying the Rosin‐Rammler model showed that the homogeneity factor of size distribution was 2.22 for the optimal crystals.

Production of micronized ammonium perchlorate particles (AP) (< 25 μm) has a great importance in the composite solid propellant industry. In the present study, an attempt was made to consider thermo-kinetic preparation of AP particles by using simple McCabe model in a cooling crystallization system. For this reason, an experimental design based on temperature, pressure, time, and concentration was used. Temperature in the range of 323-343 K, pressure in the range of 3�10 5 -18�10 5 Pa, and concentration in the range of 0.4-0.5 g/mL were set for the experiments. The time parameter was variable regarding to the temperature and concentration of each experiment and it was measured to evaluate the rate of process. The crystal size as an experiment response was estimated using image analysis of produced samples by MIP software in micrometer scale. Finally, a growth rate equation was established considering the results obtained from temperature variations, pressure, concentration, and time. Decrease in temperature variations caused to increase in crystallization rate and crystal size. The pressure above 7.5�10 5 Pa resulted in producing crystals smaller than 40 μm. The lowest crystal size was observed in the concentration of 0.45-0.5 g/mL and the crystallization time below 8 s. In addition, the results obtained from presented equation and experiment were matched with McCabe model.

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