Experimental optimization of wetting agents for different coal types and study of wetting mechanisms

This study investigates the impact of various wetting agents on the wetting characteristics of coal samples exhibiting different degrees of deterioration. Initially, surface tension and settling time were assessed to determine the optimal ratios of wetting agents. Subsequently, the interaction between the coal surface and the wetting agents was examined utilizing scanning electron microscopy and energy-dispersive X-ray spectroscopy. Finally, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were employed to analyze the alterations in the functional group content of the coal samples following treatment with the wetting agents. The results showed that the surface carbon content of lignite decreased by 27.64 % and the oxygen content increased by 23.59 % after 0.5 % SLES treatment, while the surface carbon content of bituminous coal and anthracite decreased by 13.70 % and 14.12 %, and the oxygen content increased by 13.57 % and 13.13 % after 0.6 % AEO-9 treatment, respectively. The content of hydrophilic groups (OH, C--O, C-O, C-O-C) increased significantly, while the content of hydrophobic groups (C-C, CH, CH3, CH2&CH3) decreased significantly, indicating that the wetting agent can improve the wettability of coal samples by changing the content of hydrophilic and hydrophobic functional groups on the surface of coal. The results of the study can provide guidance for different coal mines to preferably select efficient wetting agents to wet the coal body, which is of great significance to improve the wettability of coal dust. which contributed to an improvement in their hydrophilicity. The results of this research possess considerable practical implications for the control of coal mine dust.