This GEA Messo PT Standard Salt Wash consists of a stirred tank
washer/dissolver, a separation station combined with an optional
washing-thickener and a centrifuge. The salt wash is countercurrent as
follows:
Roller mill in a salt wash factory
The crude salt is first milled (not shown in the sketch above) to a certain
particle size distribution necessary for its subsequent processing, and also to
destroy inclusions of mother liquor in and remove foreign particles from the
salt crystals. Such is the case with Gypsum which can be separated with greater
ease from the salt after the size reduction step.
The milled salt is
then slurried in an agitated wash tank with wash liquor, which is
undersaturated with respect to respect of the soluble impurities (MgCl2, MgSO4
and KCl). These impurities are dissolved by the wash liquor, thus reducing the
amount by which they are present on the crystal surfaces.
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