A separation process in which suspended particles in a liquid are carried to the surface by air or gas bubbles attached to them. The air or gas is blown as bubbles through the liquid and the particles are removed from the surface. It is widely used in the mining industries for the separation of minerals, such as copper, lead, and zinc, and gangue. It (p. 151) is also used for the separation of oil from oil sands. A flotation agent is a surface-active substance added to improve the separation process by promoting the attachment of the particles to the bubbles. Other reagents that may be added can improve the stability of the foam to facilitate the removal of the froth of solids. See ore flotation.