Improving coal powder wettability using electrolyte assisted surfactant solution

Evidence has shown that the prevalence of Coal Worker's Pneumoconiosis (CWP) has been increasing among coal workers due to over-exposure to coal dust. Water spray is a widely used approach to suppress the coal dust in underground coal mines. The high surface tension of water prevents the water droplets to effectively capture coal particles. Although the addition of surfactant into water has been implemented in the mining industry to increase dust suppression efficiency. However, it is still a challenge to most of the mining industries for meeting the latest regulation. Studies have shown that the suppression efficiency could be improved significantly by using the surfactant with the addition of electrolyte. Thus, the selection of an optimum compounding solution is important. In this study, a standardised sink test method, which is reliable and accurate, was first proposed for evaluating the wettability of surfactant solutions. After that, the established standardised sink test method together with the commonly used surface tension test is used to evaluate the effectiveness of adding four different electrolytes to three types of surfactants. The finding of this paper provides the insight of an easy-conduct sink test method which may benefit other researchers who conduct similar tests. And the result reveals that the addition of electrolyte can significantly improve the coal powder wettability in anionic and cationic surfactant solutions. This study provides a starting point for the development of a more efficient low-cost dust suppression solutions.