The detachment force of air bubbles from the surface of fluorite immersed in aqueous solutions of decyl-, dodecyl- and tetradecyl ammonium chloride at different concentrations was measured. Simultaneously, the instantaneous contact angle and the height of the air bubble at the moment of detachment were determined. From the results obtained, the work of adhesion of an air bubble to the surface of a fluorite grain was evaluated and compared with that determined on the basis of Young＇s equation. Based on the measurements and calculations carried out, the detachment force was found to depend on the concentration and length of the alkyl chain of the surfactants. A linear relationship between the recovery of fluorite by flotation in the presence of the n-alkylammonium chloride salts and the detachment force was also found, as well as good agreement between the work of adhesion of an air bubble to the fluorite determined from the detachment force and from Young＇s equation.