Collector adsorption during froth flotation

The adsorption of oleate on ferric oxide, conditioned in aqueous solution at pH 9.0, has been determined from the heat of combustion of the adsorbed oleate by differential thermal analysis. Measurements were made over a range of oleate concentrations on the conditioned material prior to flotation and on floated ferric oxide. The resulting adsorption isotherms show that the floated material usually carries less, and never more, adsorbed oleate than the conditioned but unfloated material. This is contrary to what would have been expected front the work of Digre and Sandvik; the explanation is probably that sorption equilibrium conditions hare been established in our measurements, but not in those of the workers mentioned above.