Research of wetting selectivity and wetting effect of imidazole ionic liquids on coal

Abstract

In order to reduce the amount of coal dust, it is necessary to select the optimal concentration of ionic liquid to achieve the most significant wetting effect for a specific coal sample. In this paper, different concentrations of imidazole ionic liquids [Bmim][Cl], [Bmim][BF4] and coal samples were selected. Through proximate analysis, ultimate analysis, coal micro-component analysis, the DSA25 optical droplet morphology analysis system, and Scanning electron microscope was used to study the wetting selectivity and wetting effect of ionic liquid on coal. The results show that the magnitude of the surface tension of the ionic liquid affects the size of the contact angle, and the key ion [Cl]− or [BF4]− that reduces the contact angle is not a single role but requires [Bmim]+ synergy. The change of the contact angle shows that [Bmim][Cl] has a significant wetting effect on #I (hvBb) when the concentration is 6%, and [Bmim][BF4] on #II (sa) and #III (hvAb) at 8% has the best wetting effect. Besides, the less vitreous group in the maceral content of coal sample, the more oxygen content in the element, the stronger wettability, meanwhile, the rougher the surface morphology of coal samples treated with ionic liquid, the stronger the water storage capacity and the better the wetting effect. This article provides the basis for different imidazole ionic liquids to select specific coal samples to improve coal mine wetting efficiency, which is of special significance to actual production.