Study on wetting mechanism of nonionic silicone surfactant on coal dust

Coal dust disasters are serious in coal mining. The use of nonionic surfactants can effectively improve the wettability of coal dust and reduce the content of suspended coal dust in the air. For the problem of low wettability of ordinary surfactants, this paper selects silicone surfactants with high surface activity and low surface tension to improve the wetting ability of coal dust. To explore the wettability of nonionic silicone surfactants on coal dust, the effects of six nonionic silicone surfactants on the wettability of coal dust surfaces were studied by experiments. The test objects were four kinds of coal samples with different metamorphic degrees. The surface tension, wetting time, and contact angle experiments were carried out, and the critical micelle concentration and the expansion coefficient of the coal surface were calculated. The wetting time of the compound solution was measured to verify the synergistic effect of the compound solution. The results show that: 6 # has the best wetting effect on coal dust, followed by 4 # and 2 #; The order of surface tension is: 1 # < 3 # < 4 # < 6 # < 5 # < 2 #, the surface tension of 1 # is the lowest (19.962 mN/m); 1 # and 4 # are easier to spread on the surface of coal dust, the spreading coefficient of coking coal is the largest and the contact angle is the smallest, which is 18.8°. The 4 # and 6 # with a mass ratio of 8:2 were compounded. The compound surfactant solution had a significant synergistic effect. Compared with the monomer surfactant solution, the wettability of long-flame coal and coking coal increased by 15.14% and 10.00%, respectively. The results of this study can provide reference and experimental support for the development of high-efficiency dust suppressants based on silicone surfactants.