Nucleation is a combined result of thermodynamics and kinetics. Calcium sulfate dihydrate (DH), a-calcium sulfate hemihydrate (a-HH) both have the potential to precipitate when the solution is supersaturated to them. Simulation of the competitive nucleation of DH and a-HH in concentrated CaCl2 solutions at 95oC is performed to predict the phase occurrence. At low supersaturations (SHH), relatively stable phase a-HH nucleates predominantly because of the comparatively lower supersaturation of DH (SDH). At higher SHH, the metastable phase DH crystallizes prior to a-HH due to its lower interfacial energy. The addition of CaCl2 further lowers down the SDH provided the supersaturations for a-HH crystallization are equal. The advantage of supersaturation makes a-HH nucleates faster at relatively higher supersaturations. Hence, the predominant nucleation scope for a-HH is enlarged with the increment in CaCl2 concentration. The nucleation kinetics evolution accounts for the phase occurrence.

Simulation of the competitive nucleation between calcium sulfate dihydrate and calcium sulfate hemihydrate in concentrated CaCl<sub>2</sub> solutions

244th National Meeting (2012)

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Simulation of the competitive nucleation between calcium sulfate dihydrate and calcium sulfate hemihydrate in concentrated CaCl2 solutions

Simulation of the competitive nucleation between calcium sulfate dihydrate and calcium sulfate hemihydrate in concentrated CaCl₂ solutions