The Balanced Nucleation and Growth Model for Controlled Crystal Size Distribution

ABSTRACT

The Balanced Nucleation and Growth Model for Controlled Crystal Size Distribution

Ingo H. Leubner, Journal of Dispersion Science and Technology 23:577-590 (2002)

Crystal size and size distribution in precision controlled precipitations is modeled using the balanced nucleation-growth (BNG) process model.

The BNG model predicts the experimental result that many crystallization processes lead to a limited number of crystals during a nucleation period followed by growth. The crystal size distribution, maximum crystal size, Lm, number of crystals, Nm, and nucleation time, te, are modeled as a function of molar reactant addition rate during nucleation, Ra, nucleation efficiency, Fn, critical nucleus size, Ln, and crystal maximum growth rate, Gm.

The model predicts that the maximum crystal size, Lm, is independent of addition rate, Ra, and the nucleation efficiency, Fn. The crystal size increases with nucleus size, Ln, and crystal maximum growth rate, Gm. The nucleation time, te, is independent of addition rate, Ra. It increases with increasing nucleus size, Ln, and decreases with increasing nucleation efficiency, Fn, and growth rate, Gm. The crystal size distribution is independent of addition rate, Ra, and growth rate, Gm. The fraction of small size crystal population increases with increasing nucleus size, Ln, and at low growth rates, Gm. The crystal size distribution narrows with increasing nucleation efficiency, Fn. In combination of effects, each variable has its own fingerprint and may be experimentally discerned from the others.