The addition of frothers in the flotation process has a significant effect on the hydrodynamic properties of the pulp phase as well as the stability of the froth phase. Some flotation collectors have been reported to have similar hydrodynamic effects, but there are few published quantitative studies. In this paper, the pure forms of the main families of sulfhydryl collectors from thiophosphates, xanthates and xanthate derivatives are tested. The aim was to determine the hydrodynamic properties of each reagent and to examine frother-collector interactions in terms of hydrodynamics. Experiments were carried out in a two phase air-water system using a 3 in. diameter column. Gas holdup (epsilon(g)) and foam height (Hf) were measured to construct hydrodynamic characterization curves. The collectors tested have varied hydrodynamic activity with the xanthogen subgroup of collectors showing different degrees of hydrodynamic activity depending on their structure. In general, sulfhydryl collectors used in salt formulations showed very little hydrodynamic activity, while the oily collectors showed varied hydrodynamic effects from frother-type behavior to defoaming. In all frother-collector blends tested, a variable degree of foam stability loss was observed with this effect more pronounced in blends of weak frother and collector. A slight increase in epsilon(g) was measured for almost all of the collector-frother blends. (C) 2016 Elsevier Ltd. All rights reserved.