In modeling flotation, the process of bubble-particle interaction is usually divided into three subprocesses, including collision, adhesion and detachment. Of these, the hydrodynamics of bubble-particle collision has been studied most extensively by many investigators, and the results are useful for the design and scale-up of flotation cells. The process of adhesion, on the other hand, is least understood because it is essentially controlled by the chemistry of the system, which is complex and difficult to model mathematically. However, it is possible to determine the probability of the bubble-particle adhesion from the induction times that can be measured experimentally under different chemical environments. Furthermore, the new information reported in the literature on the hydrophobic forces of both particles and bubbles allow prediction of adhesion probabilities using various surface chemistry parameters. Consideration of both the hydrodynamic and surface force parameters is essential in predicting flotation rates from first principles. (C) 2000 Elsevier Science B.V. All rights reserved.