One type of gravity separator lifts the material by vacuum over an inclined vibrating screen covered deck.
[1] This results in the material being suspended in air while the heavier impurities are left behind on the screen and are discharged from the stone outlet.
Often other methods are applied to make the separation faster and more efficient, such as flocculation, coagulation and suction.
The table inclination, speed of eccentric motion and the feed rate can be precisely adjusted to achieve smooth operation of the machine.
[2] Heavy liquids such as tetrabromoethane can be used to separate ores from supporting rocks by preferential flotation.