Decantarea

Decantarea, or decantation, is a separation technique used to separate a liquid from a mixture by pouring off the liquid while leaving behind the heavier phase, such as sediment, or to separate immiscible liquids that form distinct layers. The method relies on differences in density and is commonly preceded by allowing the mixture to settle. Once separation occurs, the upper liquid is carefully poured or siphoned away, preserving the other phase. The process can operate under gravity or be aided by centrifugal force (centrifugation).

In laboratory practice, decantation is used to remove the supernatant liquid after sedimentation or centrifugation, to separate immiscible liquids, or to obtain a clearer liquid from a suspension. In winemaking, decantarea describes pouring wine away from sediment into another vessel, often to aerate the wine and enhance aroma and flavor. In civil, environmental, and chemical engineering, decantation is part of sedimentation processes in clarifiers, where clarified liquid is separated from settled solids.

Limitations and considerations include its effectiveness mainly for coarse or well-separated phases; fine particles, stable emulsions, or highly viscous liquids can hinder complete separation and may require alternative methods such as filtration or centrifugation. Proper technique aims to minimize disturbance of the settled material and to prevent re-suspension during pouring.