Optimization of the effect of synergistic action between NH ₄ F and NH ₄ Cl on ammonium sulfate crystallization using response surface methodology

To investigate the effects of NH4F and NH4Cl on the crystallization process of ammonium sulfate, experiments were designed using response surface methodology. Combined with the evaporation crystallization method, the study explored the combined effects of NH4F and NH4Cl, stirring rate, and pH on crystallization. The results indicate that the synergistic ratio of NH4F to NH4Cl and stirring rate significantly influence the crystallization yield of ammonium sulfate, with the order of effect intensity being synergistic ratio of NH4F to NH4Cl > stirring rate > pH value. The interaction between the synergistic ratio and stirring rate significantly affects the crystallization yield. All three factors significantly influence the average particle size, with their effects following the same pattern as crystallization quantity. Furthermore, the synergistic interaction between crystallization quantity and pH value significantly impacts particle size. The model predicted optimal process parameters as follows: NH4F:NH4Cl = 3:1, stirring speed = 200 rpm, pH = 4.74. Under these conditions, the theoretical crystallization yield was 57.39 g with an average particle size of 1.25 mm. Validation experiments showed that the actual crystallization yield under these conditions was 58.47 g with an average particle size of 1.23 mm, indicating a small error margin.