Effectiveness of Complex Esters According to the Integral Criterion of Molecular Electronegativity in the Flotation of Gas Coal

Abstract

The interaction of complex esters of linear and aromatic structure with the surface of Kuznetsk Basin gas coal is analyzed. The interacting coal particles and the molecules of the collecting agent are studied in terms of chemical, physicochemical, and quantum-chemical characteristics. Analysis of chemical and structural-group composition of Komsomolets colliery coal, as well as quantum-chemical entity descriptors modeling the structure of the organic unmined coal, indicates the presence of electrophilic adsorption centers on the coal surface formed due to the presence of oxygen-containing groups in their composition. It is shown that the coal surface hydration is due to the adsorption of water molecules on the electrophilic centers of the organic unmined coal. The results indicate that compounds with more pronounced nucleophilic properties than water may be effective flotation reagents. On account of the displacement of the electron density toward the oxygen atoms, complex ester molecules contain nucleophilic centers capable of electrostatic interaction with electrophilic sections of the coal surface by a charge-controlled mechanism. By analysis of the quantum-chemical characteristics of such compounds, as well as their adsorbing and flotation properties and their ability to induce hydrophobic behavior, it is established that the electronegativity of complex esters is correlated with the physicochemical characteristics of the coal surface.