METASTABLE SOLUTION THERMODYNAMIC PROPERTIES AND CRYSTAL-GROWTH KINETICS

The crystal growth rates of NH4H2PO4, KH2PO4, (NH4)(2)SO4 . 12H(2)O, N aCl, and glycine and the nucleation rates of KBr, KCl, NaBr . 2H(2)O, (NH4)(2)Cl, and (NH4)SO4 were expressed in terms of the fundamental dr iving force of crystallization calculated from the activity of supersa turated solutions. The kinetic parameters were compared with those fro m the commonly used kinetic expression based on the concentration diff erence. From the viewpoint of thermodynamics, rate expressions based o n the chemical potential difference provide accurate kinetic represent ation over a broad range of supersaturation. The rates estimated using the expression based on the concentration difference coincide with th e true rates of crystallization only in the concentration range of low supersaturation and deviate from the true kinetics as the supersatura tion increases.