Effect of welan gum and carbomer on foam and wetting properties of sodium alpha-olefin sulfonate for coal dust control

Abstract

Using foam to reduce coal dust is one of the effective means to control coal dust pollution. In this work, the solution and foam properties of foaming agents consisting of sodium alpha-olefin sulfonate (AOS), welan gum (WL) and carbomer (CBM) were investigated, the wetting ability of the composite system on coal dust was compared, and the adsorption mechanism among AOS, WL and CBM was analyzed. The results show that with the increase of AOS concentration, the viscosity of AOS/WL solutions decreases gradually and then becomes stable, while the viscosity of AOS/CBM solutions displays an opposite trend. The addition of WL and CBM promotes foam production at low AOS concentrations but inhibits it at high concentrations. Both WL and CBM can improve the liquid volume and half-life time of foam drainage of AOS solutions. The WL molecules spontaneously form a zipper network structure, making the foam liquid film significantly thicker and slightly enlarging the bubble size. The addition of CBM can form a viscoelastic surface layer on the Plateau borders, making foam less permeable and delaying the bubble Ostwald ripening. The wetting time of coal dust is extended after adding WL and CBM. These results can provide theoretical guidance for the formula study of foaming agents for coal dust suppression.