Abstract
In order to reduce the occupational health hazard of coal dust to miners, surface tension and viscosity tests and bituminous coal powder sedimentation experiments were conducted. A composite dust suppressant with bonding-wetting effects was developed. Meanwhile, based on the FTIR test and peak-differentiating curve fitting, the changes of peak areas of coal samples before and after dust suppressant treatment were investigated, with quantitative analysis on hydrophilic and hydrophobic groups. Gravity drop weight tests and Malvern particle size analyses were carried out. The particle size distribution was studied based on the Boltzmann function model. The characteristic particle size theory was adopted to analyze dust reduction performance and time's effect on the performance. Results show that the surface tension of the composite dust suppressant is 31.02 ± 0.09 mN/m with the viscosity being 84.60 mPa·s for the mixture of 0.1% SDS solution and 0.4% CMC-Na solution being 1:5. The ratio of the hydrophilic group of bituminous coal reaches 97.37% affected by the dust suppressant with a good wetting and cohesiveness effect. The characteristic particle size D (10) of dust increases by 11.77 and 46.67%, D (50) rises by 7.56 and 36.89%, and D (90) grows by 10.56 and 32.96%, respectively. The compressive strengths of the Shenmu coal sample and Lucun coal sample increase by 82.86 and 66.72% compared with that of raw coal after 48 h of dust suppressant treatment. The breakage degree at the end face of treated coal is smaller than that of raw coal. The composite dust suppressant makes the particles in coal more cohesive and effectively weakens the dust-producing property. Research results are of practical significance for improving the effect of water injection on dust reduction.