In underground coal mines, the efficiency of water-based dust suppression technologies is heavily limited by the poor wettability of coal dust. To explore the effect of the surface pore parameters of coal dust on its wettability, in this study, 18 original coal dust (OCD) samples produced in underground mining sites were collected from various underground coal mines in north China. The surface micropore (pore size < 2 nm) and mesopore (2 nm < pore size < 50 nm) characteristics of the OCD samples, including the pore size, pore volume, fractal dimensions of pore volume, and specific surface area (SSA), were measured with the nitrogen (N2) adsorption/desorption method and computed with various computation models. Subsequently, the correlations between the surface pore characteristics of the OCD samples and their moisture contents were established. The results demonstrate that the pore structures of the OCD samples are significantly developed, and the micropore structure of the OCD samples considerably affects the moisture content. The moisture content of the OCD samples decreases logarithmically when R2 = 0.80 following the increase in the micropore size. It indicates that the micropore of the coal dust has significant water-retention property, which could greatly improve the wettability of coal dust.

coal dust, physicochemical properties, wettability, particle size, pore structure.