Mixing Effects on Crystal Growth

Several references on nucleation provide excellent insight into this complex phenomenon, including Mersmann (2001), MuUin (2001), and Myerson (2001). 

Mixing can obviously have a large effect on the mass transfer rate of growing crystals through its effect on the film thickness. This influence is dependent on both the size of the crystals and the mixing intensity. As mixing intensity increases, mass transfer rate increases and film thickness decreases up to a limit, beyond which the effects approach limiting values. 

The concentration gradient in the film is illustrated in Fig. 6-3, where it can be seen that supersaturation conditions are present throughout the film. When crystaUization is diffusion limited, concentration in solution drops significantly from that in the bulk (Cb) to that in the film (Cf), which is close to that at the crystal growth surface (Csurf)- When growth rate is primarily limited by resistances to surface incorporation, the larger drop in concentration is 

Da for crystallization = mixing time/overall crystal growth time 

mixing time and supersaturation release time can be those required to achieve 95% or percentages of the final state. 

---