Effective foaming agents for coal flotation: A quantum-chemical approach

Abstract

The effectiveness of the following compounds as foaming agents is evaluated: heteropolar ketones and sulfoxides whose molecules contain oxygen and sulfur; and petrochemical products such as butanol bottoms and T-80. The use of methylhexyl sulfoxide instead of butanol bottoms increases the extraction of the coal’s combustible component in the concentrate from 87.1–90.9% to 93.9–95.25%, with simultaneous decrease in reagent consumption by ~20%. That may be attributed to the excellent foaming properties of methylhexyl sulfoxide and its ability to render the coal particles hydrophobic. The flotational activity of compounds with different functional groups in the molecule may be compared on the basis of the energy of the hydrogen bond in molecular complexes of the reagent with the coal’s organic mass. In molecular complexes of methylhexyl sulfoxide with model compounds in the coal’s organic mass, the energy of the hydrogen bond is considerably greater than that for the corresponding molecular complexes of methylhexyl sulfoxide with model compounds in the coal’s organic mass. That ensures 35–45% increase in the adsorption of methylhexyl sulfoxide on the coal surface in comparison with methylhexyl ketone and also results in more hydrophobic coal grains, which undergo more effective flotation.