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The Balanced Nucleation and Growth Model for Controlled Crystal Nucleation and Size Distribution – I. The Model

Ingo Leubner, Crystallization Consulting, Penfield, NY

The Balanced Nucleation and Growth (BNG) Model was first proposed and experimentally supported in 1980(1-4). The BNG model has correctly predicted previously unknown nucleation behaviors.

The present derivation of the BNG model is based on the classical concepts of Becker and Doering, but replaces the kinetic nucleation rate with the introduction of crystal growth processes during the nucleation phase.

The BNG model predicts the experimental result that many crystallization processes lead to a limited number of crystals during a nucleation period which is followed by growth only. Further, the model predicts the crystal formation during the nucleation phase, the crystal size distribution, maximum crystal size, number of crystals, nucleation rate and time. Model variables are the molar reactant addition rate during the nucleation phase, nucleation efficiency, critical nucleus size,and maximum crystal growth rate. These are related to experimental parameters. Without growth, the crystal number is proportional to addition rate and nucleation occurs continuously during the time of reactant addition.

The BNG model was originally derived for balanced double-jet batch precipitation, and later extended and experimentally confirmed for controlled double-jet continuous crystallizations. (5)

1. Leubner, I. H., et al, Photogr. Sci. Eng., 24:268 (1980); 2.Leubner, I. H., J. Phys. Chem., 91:6069 - 6073 (1987; 3. Leubner, I. H., J. Disp. Sci. Technol., 22 :125 – 138 (2001); 4. Leubner, I. H., J. Disp. Sci. Technol., 23:577 – 590 (2002); 5. Leubner, I. H., J. Imaging Sci. Technol., 42:357(1998)



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