Removal and Separation of Particles by Crystallization

摘要

Pushing and incorporation of foreign particles during solidification were studied. Trapping was favored by rapid freezing, a small amount of stirring, and the presence of gas bubbles at the interface, and by formation of an acute angle between the interface and the container. With faceted growth, trapping differed from grain to grain and was sometimes favored at a grain boundary. The temperature gradient had no effect on particle trapping. Particle mixtures were separated by slowly increasing the freezing rate. This is called particle chromatography. A theory was developed for nucleation of gas bubbles during crystallization. (Author)