Recrystallisation

Recrystallisation is a purification process, in which impure crystals are dissolved in a clean solvent, and then recrystallized, to produce crystals that are significantly purer (10X or better) than those used for the feedstock. The actual method of crystallisation can be that of evaporation or cooling, depending upon the solubility of the product; usually the recrystallisation operation is a repetition of the first crystallisation unit. Recrystallisation is typically used for products that require high levels of purity (usually >99.9%), such as pharmaceutical grade or reagent grade components.