The volume of froth generated in the flotation machine under standard operating conditions is often referred to as froth power. The froth power is influenced by the type of collector and frother used. For example, froth power normally increases with the number of carbon atoms in the hydrocarbon radical up to 6 or 7, and then drops dramatically when the hydrocarbon chain has more than 8 carbon atoms. A xanthate with less than 6 carbons
in the alkyl group does not produce frothing alone, while octyl xanthate will produce froth on its own but will diminish froth if mixed with alcohol.
Mixing a longer chain xanthate (amyl) with a short chain alcohol increases the volumeof the froth. The froth power increases strongly when amyl xanthate is combined with an alcohol containing 7–8 carbon atoms in the hydrocarbon radical. Xanthates with a shorterchain length (ethyl) decrease the froth power for alcohols with 5 or less carbon atoms.
In fatty acid flotation, certain alcohol-type frothers, such as pine oils, cresylic acid, etc. act as froth modifiers. For example, mixing tall oil fatty acid with a cyclic alcohol frother (pine oil) produces a froth that has improved loading properties and that collapses after discharge.
In cationic flotation with amines, addition of frother to the amine reduces collector consumption and improves the rate of flotation.