Micromechanism Analysis of Surfactant Wetting of Coal Based on ¹³C NMR Experiments

With the gradual improvement in coal mine mechanization and automation, the dust concentration at production sites is increasing significantly as the production efficiency improves, which not only poses a substantial threat to the occupational safety and health of workers but also affects the safe production and social stability of mines. At present, wet dust removal is the most economical and effective technical dust removal measure. However, most coal seams in China have poor wettability, unclear microscopic wetting mechanisms, and poor dust removal effects. Therefore, based on experiments and numerical analysis, this paper qualitatively studies the influencing factors of surfactants on coal wettability and quantitatively constructs an innovative evaluation model of the influence of the microstructure of coal and surfactants on wettability. First, based on ¹³C NMR experiments, the structural parameters of coal and several surfactants were obtained. Second, the wettability relationship between the coal and the surfactants was determined by optical titration, and the key factors affecting the wettability of coal dust and the wettability of the surfactants were selected. Then, using numerical analysis and function fitting analysis and combining the structural parameters with the coal wetting results, the relationship between the microstructure of the surfactants on different kinds of coal and the wettability of the coal samples was established. The results show that the ether group, the phenol or aromatic ether carbon, the fatty methyl group, and the aromatic methyl group in the surfactants have a substantial influence on the wettability. The research results can provide scientific guidance for the development of efficient and environmentally friendly compound dust suppressants to realize clean production in mines.