| MadSci Network: Chemistry |
Sorry I have taken a long time to reply.
Freezing is one method of desalination (the others being reverse osmosis and distillation). The salt water is cooled so that the water starts to crystallise; the salts are excluded from the crystals as water molecules "prefer" to crystallise with themselves (H-bonding and all that!). The resulting mixture of pure water ice crystals and concentrated salts is filtered and the ice washed to remove traces of salts from the surface. The ice crystals are then thawed out.
It has not been developed as commercially viable, because, although theoretically cheaper than other methods and with other advantages, the handling of the large quantities of ice crystals is difficult.
Kevin
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