Experimental study on synergistic wetting of a coal dust with dust suppressant compounded with noncationic surfactants and its mechanism analysis

To improve the ability of water spray additives to wet coal dust, the compounding wetting characteristics of several nonionic and anionic surfactants on bituminous coal dust were studied, the surface tension, contact angle and the settling time of coal dust were measured. Results showed that the compounding of sodium dodecyl sulfate (SDS) and two other anionic surfactants exhibits an antagonism effect and reduces the wettability of water. The compounding of primary alcobol ethoxylate (JFC), ethylene glycol polyoxyethylene ether (PEG800) and the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) achieves the strongest synergistic effect at a mass ratio of 3:1:1. Furthermore, the infrared spectra of raw coal and coal treated with dust suppressant showed that the hydrophilicity of coal dust is improved after the treatment by dust suppressant. Finally, the synergistic effect mechanism of JFC, PEG800 and SDBS was explained from the perspective of molecular and hydrogen bond. [Display omitted] •The wetting characteristics of noncationic surfactants on coal dust was studied.•A dust suppressant compounded by JFC, PEG800 and SDBS was proposed.•The hydrophilicity and hydrophobicity of coal dust before and after treatment with dust suppressant were analyzed.•The mechanism of synergistic wetting of coal dust by JFC, PEG800 and SDBS was analyzed.