Evaluation of the coal dust suppression efficiency of different surfactants: A factorial experiment

Coal dust is a main health hazard in underground coal mines. A recent report showed that a number of coal workers were diagnosed with pneumoconiosis in Australia. Water spray with addition of surfactant has been considered as an effective method to control the coal dust. Numbers of static studies showed surfactant could increase the coal dust wettability effectively. In fact, the contact of coal dust and surfactant droplet is dynamic and more complicated due to the short contact time. Wind tunnel tests are able to present this dynamic process. In this study, a factorial experiment was designed to evaluate the suppression effectiveness for three factors such as (i) different types of surfactants at (ii) different levels of their solutions on (iii) different initial concentrations of coal dust. Four surfactants with seven levels were investigated under two initial coal dust concentrations. The results showed that all the three-factors could affect the suppression efficiency significantly. Surfactants gave higher efficiencies when the initial coal dust concentration was low. Sodium dodecyl sulphate (SDS) and cetyltrimethylammonium bromide (CTAB) performed better than other two surfactants regardless of the initial coal dust concentration. The limitations of this study were also analysed. The results of this study could be used by researches and industry to determine an effective surfactant for coal dust suppression.