Optimization of Ammonium Sulfate Crystallization Under Ammonium Nitrate Based on Response Surface Method

Abstract

AbstractThe response surface method is used to study the influence mechanism of three factors (seed crystal concentration, pH value, and stirring rate) on ammonium sulfate crystallization (average particle size and coefficient of variation [C.V.] value) under ammonium nitrate to prove the effect of ammonium nitrate doping on ammonium sulfate crystallization. Regression equations between each response value and the influencing factors are established. Results show that the interaction between the seed crystal concentration and the stirring rate is stronger than that between the seed crystal concentration and the pH and that between the pH and the stirring rate. The error between the verified model values and the experimental values is minimized when the seed crystal concentration is 1.5%, the pH is 4.5, and the stirring rate is 250 r min−1, at which the average particle size is 1.238 mm, and the C.V. value is 73.53. After optimization, the crystal morphology changes from needle‐ and flake‐like crystals to cubes, resulting in crystals with large average particle size, uniform distribution, regular morphology, and diffraction peak intensity that is close to that in the analysis of pure ammonium sulfate.