Effects of preparation parameters on the wetting features of surfactant-magnetized water for dust control in Luwa mine, China

To effectively improve the wetting ability of water used for coal dust suppression in China's Luwa mine, surfactant-magnetized water was proposed because of the synergy between magnetization and surfactants. The wetting features of this product were systematically studied under various preparation parameters. In addition to the surface tension and contact angle, the capillary force and spreading work were used to better evaluate the product's solution wettability (The latter two parameters reflected the permeation and spreading ability between the solution and coal dust, respectively.). The results showed that the surfactant-magnetized water generated by adding a compounding solution (containing 0.03 wt% surfactant and 0.05 wt% NaAc) and passing the solution through a 350 mT magnetic field at a water velocity of 4 m/s had the optimum capacity to wet coal dust, and increased the spreading work by 94.9% (to -2.56 mN/m) compared to that of untreated water, and decreased the contact angle to 25.47 degrees. To easily optimize the preparation parameters of surfactant magnetized water, an evaluation system of solution wettability was constructed on the basis of the contact angle, wettability improvement ratio and spreading work of the solution. Field testing proved that the dust suppression efficiency of the optimized surfactant-magnetized water exceeded 84% and was much higher than that of the water spray alone, significantly reducing the dust concentration at the working face. (C) 2017 Elsevier B.V. All rights reserved.