Foam Separation Selectivity Conditioned by the Chemically Attached Agent
S. A. KONDRAT’EV1, N. P. MOSHKIN2
1Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Krasnyi pr. 54, Novosibirsk, 630091 Russia
2Lavrent’ev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent’eva 15, Novosibirsk, 630090 Russia
Keywords: flotation, hydrophobic behavior, hydrophilic behavior, mineral particles, nanobubbles, chemical adsorption, critical film thickness, selectivity
Abstract
It is hypothesized that the critical thickness of rupture of a liquid film between air bubble and mineral particle depends on potential and size of area occupied by nanobubble. It is shown that the critical thickness of the film equals the height of meniscus formed under rupture. The size and shape of meniscus are characterized by its neck radius and contact angle. The proposed hypothesis is based on the assumption that the size of initial meniscus neck is connected with the diameter of attachment area of nanobubble. There are no nanobubbles on the surface of hydrophilic minerals, and the liquid film rupture is hampered in this case. Since liquid film stability is mainly affected by hydrophobic interaction, the liquid film rupture thickness is larger on hydrophilic minerals than on hydrophobic minerals. Selectivity of foam separation of minerals, governed by the chemically attached agents, depends on the ratio of the critical rupture thicknesses of the liquid film.
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