Nucleation Thermodynamics and Nucleation Kinetics of Ammonium Sulfate under the Synergistic Action of Ammonium Chloride and Ammonium Fluoride

Abstract

In order to investigate the nucleation thermodynamics and nucleation kinetics of (NH₄)₂SO₄ during cooling crystallization under the synergistic effect of different ratios of NH₄F and NH₄Cl, the solubility and width of the metastable zone width of (NH₄)₂SO₄ in the mixed solution were determined by gravimetric and laser methods by incorporation of (NH₄)₂SO₄ in a mixture of different ratios of NH₄F and NH₄Cl in this study. It is demonstrated that the dissolution of (NH₄)₂SO₄ is a heat-absorbing process, that the inhibition of (NH₄)₂SO₄ nucleation by NH₄F is much greater, and that the intermediate stabilization zone of (NH₄)₂SO₄ is enlarged with an increase in the cooling rate. Based on the self-consistent Nývlt-like equation and the classical three-dimensional nucleation theory, the nucleation kinetics of (NH₄)₂SO₄ under the synergistic interaction of NH₄F and NH₄Cl was investigated, and the critical nucleation parameters of (NH₄)₂SO₄ under the synergistic interaction of NH₄F and NH₄Cl were obtained.