Commonly used flotation agents, except inorganic acids, bases and salts, are mainly surfactants. Surfactants play a dual role in flotation: they are adsorbed on the solid/liquid interface, making the surface of a particular mineral hydrophobic (as a collector) or hydrophilic (as an inhibitor or flocculant); secondly, they exert an influence on the foam-mineral adhesion dynamics. The latter type of surfactant is commonly used as foaming agent.
Because flotation surfactants are generally transferred to the interface through aqueous solution, the main agents used in flotation are those which are more or less soluble in water. In some cases insoluble hydrocarbons or other oils must be used in order for them to reach the interface in a relatively short time. These liquids are dispersed into emulsions in the aqueous phase by means of soluble surfactants.
Flotation reagents are mainly composed of surfactants and polymers.