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Fractional crystallization (chemistry)

In chemistry, fractional crystallization is a method of refining substances based on differences in solubility. It fractionates via differences in crystallization (forming of crystals). If a mixture of two or more substances in solution are allowed to crystallize, for example by allowing the temperature of the solution to decrease or increase, 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. Fractional crystallization can be used to separate solid-solid mixtures. An example is separating KNO3 and KClO3.

Crystallization
Process-of-Crystallization-200px.png
Concepts
Crystallization · Crystal growth
Recrystallization · Seed crystal
Protocrystalline · Single crystal
Methods and technology
Boules
Bridgman–Stockbarger technique
Crystal bar process
Czochralski process
Epitaxy
Flux method
Fractional crystallization
Fractional freezing
Hydrothermal synthesis
Kyropoulos process
Laser-heated pedestal growth
Micro-pulling-down
Shaping processes in crystal growth
Skull crucible
Verneuil process
Zone melting
Fundamentals
Nucleation · Crystal
Crystal structure · Solid

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ReferencesEdit