Fractional crystallization (chemistry)

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Snow crystallization in Akureyri 2005-02-26 19-03-37.jpeg
Crystallization · Crystal growth
Recrystallization · Seed crystal
Protocrystalline · Single crystal
Nucleation · Crystal
Crystal structure · Solid
Methods and technology
Boules · Bridgman-Stockbarger
Czochralski process
Frac. crystalliz. · Frac. freezing
Hydroth. synthesis · LHPG · Iodide process

In chemistry, fractional crystallization is a method of refining substances based on differences in solubility. If a mixture of two or more substances in solution is allowed to crystallize, for example by allowing the temperature of the solution to decrease, the precipitate will contain more of the least soluble substance. The proportion of components in the precipitate will depend on their solubility products. If the solubility products are very similar, a cascade process will be needed to effectuate a complete separation. This technique is often used in chemical engineering to obtain very pure substances, or to recover saleable products from waste solutions.

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