Application of the addition of ionic liquids using a complex wetting agent to enhance dust control efficiency during coal mining

(a) Capillary rise height for each wetting agent (b) Contact angle curves of the droplets on the coal sample. [Display omitted] •The compound process of isotropic ionic and anisotropy ionic was optimized.•The effect of wetting ability for the different wetting agents were analyzed.•The ionic liquid obviously improved the effect of the wetting agent.•The dust effect of the circular nozzle was better than the ellipse nozzle. This study investigates the effects of a compound method that involves the use of anionic, cationic and nonionic surfactants. The compound composition of the isotropic ionic and compound across of the anisotropy ionic process was proposed. An ionic liquid was introduced as an auxiliary agent to improve wetting characteristics of the mixture, resulting in a compound of wetting agent A～I. Wetting agent A and E were selected because they were more effective than others by the capillary rise method. The contact angle on Da Ning coal sample was tested. For droplets of pure water, the contact angle was 72.1°. For droplets of wetting agent A, the contact angle was 23.5°. For droplets of wetting agent E, the contact angle was 14.4°. The effect of wetting ability for the wetting agents were analyzed, and four other coal sample test results were compared. In order to test the application effect of the wetting agents. The high-pressure spray system were analyzed and developed, an adjustable nozzle and wind scooper were designed with a secondary atomization function, which improved the ability to capture dust. The application results showed that the ionic liquid improved the dust effect. The atomization effect of the circular nozzle was better than that of ellipse nozzle. When wetting agent E was added, the dust efficiency reached 90%, and the respiratory dust efficiency reached 87%. The new spray system consumes 30% less water than a traditional system, produces smaller droplets, and achieves higher dust control efficiency.