Competitive representations in studies on froth flotation and prospects of their application for selection of reagents

From the viewpoint of experimental substantiation and usefulness for the selection of reagents for froth flotation, five different representations are considered that interpret the causes of selective capture of particles by bubbles. These are the hysteresis, electrostatic, capillary, jointly radiographic and luminescent, and sophistic presentations, which were popular in the past, then rejected, and now are being developed again; they, however, contain substantial errors. Quantitative analysis has shown us that capillary presentations are preferential, with the use of which it proved possible to establish the effect that the electrical charge of the particle surface (or the ionic composition of the pulp) had on the absorption of neutral organic molecules on the surface; to determine the nature of forces that keep the particles on the bubbles; to find the interlayer of the liquid between the bubble and the substrate; to determine the properties of thin layers of the liquid, which are the “glue” keeping the particles on the bubble; to reveal the structure of the boundary layers of the liquid that are in contact with the solid and gas phases; to introduce the quantitative criterion of nonequilibrium for the characteristics of the properties of reagents, which manifest themselves in the dynamic conditions of froth flotation and, the most important, which are based on capillary physics, in order to calculate various models of froth flotation to reveal their mechanism and the causes of existence; to find the optimal conditions for solving concrete problems and the modes of conducting reagent-free, ecologically pure froth flotation. It is also important that the capillary representations allow one to easily recognize the incorrectness of not only the previously wide-spread popular (sophistic) hypotheses, but certain modern ones as well.