Study on Factors Affecting Wettability of Blasting Dust in Dexing Copper Mine

Abstract

The working face blasting dust of Dexing Copper Mine was taken as the research object, and hydrophilic dust (HD, sinking quickly to the bottom) and hydrophobic dust (HCD, floating on the surface for a long time) were separated. The wettability was quantitatively characterized by measuring the wetting contact angle of the two, and the physicochemical properties of the dust particles were comprehensively characterized by measuring the particle size distribution, surface properties, elemental composition, and phase composition of the dust particles. Finally, by comparing the differences in physicochemical properties between HCD and HD, the key factors affecting the wettability of dust were investigated. The results indicate that the wetting angle of HCD is much smaller than that of HD at any given time. When the wetting contact angle of HCD reaches 20° and is in a relative equilibrium state, HD tends to 0°. In terms of wetting properties, the average particle size of HCD is 21.97% smaller compared with HD, which makes HCD have a larger mass-specific surface area, surface energy, and surface activity. Additionally, the true density of HCD is 4.54% lower than that of HD. HCD is less affected by gravity and has a more complex surface pore structure, resulting in a more pronounced air film effect on the surface of dust particles. The formation of an air film greatly weakens the dust’s wettability. Therefore, particle size and surface structure are the main factors affecting the dust’s wettability. Organic substances cannot be detected in the HCD and HD spectra, indicating that both HCD and HD are hydrophilic phases, which determines the overall wettability of blasting dust. The phase composition of HCD and HD is similar, and the difference in the content of hydrophobic groups (C-C, C-H) between them is less than 3%, so the surface groups are not the main factors affecting the wettability of dust.