Kinetics of Dissolution and Crystal Growth

Crystal nucleation and growth are key factors in determining characteristics of crystalline products that may determine their usefulness or even the ability to separate them from their mother liquor. The kinetics of these phenomena and of dissolution are related to the difference between the values of the system variables and the values of those variables at equilibrium. In crystallization, this difference is referred to as supersaturation and it is given by the expression 

The relative supersaturation has special utility because it approximates the rigorous definition of supersaturation in Equation (21), which is related to solute concentrations by the expression 

For ideal solutions, where both yand y are approximately unity, or for conditions that lead to the approximation y = /, 

When the supersaturation ratio, 5, is small (say less than 1.1), it follows that 

For this reason, then, kinetics of nucleation, growth, and dissolution are often expressed in terms of relative supersaturation. The actual relationships for these 

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