Crystallization
Throughout the chemical process industries, formation
of crystals is an important route to products of high purity. Click
here to find out why slow forming crystals are so pure. The ultra
pure silicon wafers for the electronics industry are made by repeated crystallization.
As a crystal forms, the ions or molecules that fit exactly into the crystal
lattice are preferred while the incorrect species are excluded. Often very
pure crytals can form in quite impure solutions. Of course, when the mother
liquor (the residual solution) adheres to the crystals, purity suffers.
This is why good washing or removal of liquid from the crystals is critical.
Rapid precipitation
tends to make impure crystals.
Look at some typical crystals of the mineral aquamarine with high purity:
Single crystal
Translucent green crystal
Translucent green crystal
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26-July-95
