Influence of Surface Oxidation on the Wettability and Filtration Properties of Coal

Most processes in coal extraction (hydraulic fracturing, plugging of cracks, irrigation of the exposed mass with deactivating liquid) and initial processing (enrichment) depend on the wetting properties of the coal's external surface. Atmospheric oxidation changes the composition of the surface functional groups that determine the hydrating properties of coal. In the present work, the influence of initial oxidation of the coal on the composition of the functional oxygen and hydrocarbon groups is assessed. The wettability of the surface is characterized not only by determining the limiting wetting angle but by liquid filtration through coal powder. The differences in the wetting of the surface by water and the filtration properties on oxidation of the coal surface are established. It is found that, as oxidation proceeds, the hydration of the surface and its filtration properties increase.