Crystallization and freezing processes assisted by power ultrasound
Résumé
Power ultrasound may be used to control crystal properties in solutions and melts.
The first part of this chapter concerns the thermodynamics and kinetics of crystallization.
The second part reviews several studies dealing with ultrasound-assisted crystallization or freezing processes. The influence of operating conditions (dissipated acoustic power or intensity, frequency, duration, ultrasonic device) on crystals’ properties and process rate is discussed.
The third part investigates elementary mechanisms (temperature, pressure, diffusive, and chemical effects) underlying the sonocrystallization process according to the literature but also on the ground of authors’ own results. A special paragraph is devoted to ice crystallization in super-cooled aqueous solutions.