Wednesday, April 6, 2011

Levigation

Definition:


Levigation is the process of grinding an insoluble substance to a fine powder.

Or

Levigation is the grinding to a powder of a moist or hard substance.

Explanation:

The material is introduced into the mill together with water in which the powdered substance remains suspended and flows from the mill as a turbid liquid or thin pastes. According to the amount of water employed. There is no loss of material as dust nor injury or annoyance to the workmen.

Further any (substances) soluble impurities in the substance are dissolved and the product thereby purified.

Advantages of levigation:

The greatest advantages of levigation is the facility it affords for the subsequent separation of the products into various grades of fitness because of slower. Subsidence of the finer particles from suspension.

The turbid liquid flows into the first of a series of tanks and is allowed to stand for a time. The coarsest and heaviest particles quickly subside leaving the finer material suspended in the water which is drawn from above the sediment into the next tank.

The liquid is passed from tank to tank remaining in each longer than it remained in the proceeding since the finer and higher the particles the more time is necessary for this deposition. In some cases a dozen or more tanks may be used and the process then becomes exceedingly slow.

The term levigation is now often applied to more sedimentation a substance being simply stirred up in water without previous wet grinding.
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