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Tuesday, 20 January 2015

Crystallization

crystallization


Crystallization is the process of hardening, which leads to the formation of crystals.
It can be made from a solution, melt, the gas phase, an amorphous solid or from another crystal (re crystallization), but always through crystal formation and crystal growth. In this process, crystallization heat is released.

This results in a crystal can form the material must first be brought into super saturation. This is done for example by cooling processes from solutions or melts, or by evaporation of the solvent.

For crystalline materials, which consist of several components (for example, ionic crystals), the super saturation can also be prepared by mixing two solutions, each containing one of the components.
Here, the previously dissolved molecules or elements arranged in a regular, partly substance-specific form. This process can be accelerated if seed crystals are added, which then grow in the super saturated solution. The crystals can then be separated by filtration, flotation, and centrifugation or sieving of the solution (see also separation process). An example of obtaining a mass product by 
crystallization is the extraction of salt in salt pans.

The concept of crystallization is also used in a figurative sense, if a / someone something (a situation, a thought, etc.) gradually becomes clearer