Pure Crystallization of an API

Goals . To understand crystallization behavior upon seeding, aging, and cool-down 

Variables . Seed level, nucleation/growth at seeding temperature and cool-down profile 

When the solution is saturated or undersaturated, an interesting opposite response is observed. The total particle count decreases (Curve II of Fig. 7-15), and the mean particle size increases (Curve II of Fig. 7-16). This behavior strongly implies digestion of particles, especially fines of the (milled) seed. 

Particle count and mean size during cool-down are shown in Figs. 7-17 and 7-18. After the start of cool-down ( 200 minutes), the total particle count increases only slightly, whereas the mean particle size increases noticeably. These observations suggest that crystal growth is dominant in this period. 

A total of six parameters—seed level, seeding temperature, seed aging period, initial cool-down period, second cool-down temperature, and third cool-down period—were evaluated. In studying the effect of these six parameters, the best-fitted models (by least squares) of the data are  

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