Fractional crystallization (chemistry)

In chemistry, fractional crystallization is a method of refining substances based on differences in solubility. If two or more substances are dissolved in a solvent, they will crystallize out of solution (precipitate) at different rates. Crystallization can be induced by changes in concentration, temperature or other means.

This technique is often used in chemical engineering to obtain very pure substances, or to recover sellable products from waste solutions.

Fractional crystallization can be used for purification or analysis.