fractional crystallization

Century Dictionary and Cyclopedia

1. See crystallization, etc.

Wiktionary

1. n. physics, chemistry the separation of two solutes from the same solution by using either a solvent or a crystallization temperature such that only one solute is supersaturated and crystallizes out

GNU Webster's 1913

1. adj. (Chem.) a process of gradual and approximate purification and separation, by means of repeated solution and crystallization therefrom.