Study on competitive adhesion of coal dust on water droplet

Using the molecular dynamics simulation, we explored the interaction of water and montmorillonite/graphite at a microcosmic level. Due to the interaction between the oxygen atom at the montmorillonite (0 0 1) surface with the hydrogen atom in the water molecule, the distance between the water molecule with the montmorillonite surface was calculated to be 3.05 Å while that with the graphite surface was 3.57 Å, indicating that montmorillonite was more easily wetted than graphite. We studied the wetting behavior of coal dust particles and the adhesion behavior between dust powder with water droplets via a high-speed motion acquisition system. The coal dust powder was found to be slowly wetted until a gangue proportion of 40% above which the dust powder was wetted so rapidly. Furthermore, the wrap angle of dust powder at the droplet surface decreased as the gangue proportion increased. The competitive adhesion behavior was revealed that the pre-adhered hydrophobic particles prevented the later particles while the pre-adhered hydrophilic particles did not. The smaller experimental wrap angle as compared to the calculated values proved that the competitive behavior did occur during the coal dust adhesion process. Our results could provide valuable insight into the development of technology for coal dust removal.