Elutriation

elutriation [ē‚lü·trē′ā·shən]

(chemical engineering)

The process of removing substances from a mixture through washing and decanting.

(engineering)

In a mixture, the separation of finer lighter particles from coarser heavier particles through a slow stream of fluid moving upward so that the lighter particles are carried with it.

(geology)

The washing away of the lighter or finer particles in a soil, especially by the action of raindrops.

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Elutriation 

(or clarification), the separation of slowly settling fine particles of a polydisperse suspension from rapidly settling larger and heavier particles by decanting a liquid containing the not yet settled particles from a settled precipitate.

Elutriation is a means of hydraulic classification of ground materials (with particle size from several tenths of a micron to several millimeters) that combines settling with décantation into consecutively linked settling basins (reservoirs, tanks, or chambers). The process is used to concentrate mineral raw materials, produce fine powders, and cleanse clays (particularly kaolin) of mechanical impurities (sand, mica, and feldspar).