Levigation is the process of grinding an insoluble substance to a fine powder, while wet.
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 paste, according to the amount of water employed.
There is no loss of material as dust, nor injury or annoyance to the workmen. Further, any soluble impurities in the substance are dissolved, and the product thereby purified.
The greatest advantage of this process is the facility it affords for the subsequent separation of the product into various grades of fineness, because of the slower subsidence of the finer particles from suspension.