The hydrophobic force in flotation-a critique

Whether or not a particle is captured by a rising bubble during flotation i s determined, to a large degree, by the hydrophobic force of attraction. Th e origins of the latter force have remained obscure, despite the early insi ghts of flotation scientists. Recent evidence indicates that the surface pr operties of the solid substrate, the type and concentration of dissolved ga s, and surface microbubbles all influence the stability of the thin, aqueou s film that forms between a particle and a gas bubble during the final stag es of the capture process. The accurate description of the forces that oper ate across this film remains a serious challenge. (C) 2001 Elsevier Science B.V. All rights reserved.