Supersaturation and crystal growth in gas anti-solvent crystallization

A technique of developing a low expansion rate of solution under constant temperature was employed to examine the saturation behavior of expanded solutions and the growth of crystals in the gas anti-solvent crystallization. When solutions were expanded under pressure, three types of saturation behavior were observed. The behaviors are explicable using an chi factor. The growth phenomenon, growth rate, and growth mechanism of crystals in the GAS process were similar to those usually found in the conventional processes of solution crystallization except that millimeter-sized inorganic crystals without well-defined faces cannot re-facet themselves. (C) 1998 Elsevier Science B.V. All rights reserved.