The flotation recovery of chalcopyrite particles in a complex sulfide ore was measured in a Rushton turbine flotation cell as a function of particle size. The experimental flotation rate constants of these particles were compared to those calculated using a recently developed flotation model that incorporates contributions from the efficiencies of collision, attachment and stability between particles and bubbles, as well as their frequency of collision. For these calculations, the contact angle of the chalcopyrite particles in the ore was obtained independently using an approach based upon Time of Flight Secondary Ion Mass spectroscopy (ToF-SIMS). It was found that the calculated flotation rate constants were in good agreement with the experimental data and able to reproduce the characteristic maximum in flotation rate constant for particles of intermediate size. The values of bubble velocity and turbulent dissipation energy derived from these calculations are relatively low and may well correspond to mean values of these parameters inside the flotation cell.