Rheological behavior of kaolinite/surfactant/air bubble suspensions

•Rheological properties of the multiphase system kaolinite/surfactant/air.•Effects of vol% of air bubble on yield stress.•Effects of vol% of air bubble on suspension viscosity.•Effects of cationic, anionic and non-ionic surfactants on yield stress. The rheological characteristics of the multiphase system (kaolinite/surfactant/air bubble) were examined in both the linear and non-linear viscoelastic regimes. The response of the suspensions were studied under shear to investigate their yielding and steady-state flow behavior under shear rate- and stress-controlled conditions. Creep and strain amplitude sweep tests were also used to verify the yield stress measurement. The effects of the volume percentage of the injected air as well as types (cationic, anionic and non-ionic) and concentration of surfactants on the yield stress were investigated. It was found that the yield stress in general increases with volume% of air. The calculated capillary number based on bubble size and surface tension shows a consistent trend between air volume and yield stress.