Experimental Study On Effect Of Surface Active Ionic Liquids On Coal Dust Wettability

Coal dust has been still one of the main disasters in the coal industry.Study on dust control technology and materials based on aqueous solution has been the research hotspot of mine dust control,which has been focused more on reducing the surface tension of aqueous solution than essential change of the wettability of coal dust.Room temperature ionic liquids which have a more significant dissolution and destruction effect on coal structure than traditional reagents,can affect the physicochemical properties of surface microstructure of mine.Thus,based on the previous research,this paper has realized high wettability of coal dust by analyzing the surface active ionic liquid dual modified aqueous solution and the coal dust surface microstructure hydrophilic and hydrophobic characteristics,and the main work and results have been as follows.Firstly,six kinds of coal samples,which included lignite,bituminous coal and anthracite in three different degree of coalification,have been tested the contact angle with deionized water to macroscopically characterize the wettability of coal dust samples with different coalification degrees by using contact angle measurement instrument.And it has been found that moisture,fixed carbon,carbon and oxygen were the main factors affecting the wettability of coal dust,which moisture and oxygen were positively correlated with wettability and fixed carbon and carbon were negatively correlated with wettability.The differences in surface functional groups of coal dust samples with different coalification degrees was found by infrared spectroscopy and X-ray photoelectron spectroscopy,wettability,which wettability was correlated with oxygen-containing functional groups positively and aliphatic hydrocarbon functional groups negatively.Secondly,ten kinds of ionic liquids were used to analyze the surface tension by surface tensiometer,showing the surface activity characteristics of different ionic liquids.And it was found that surface tension of ionic liquids was less than that of deionized water in different degrees,indicating that these ionic liquids could effectively reduce the surface tension of water and enhance the wettability of aqueous solution to coal dust.Further the functionalized ionic liquids[HOEt MIm][NTf₂]and surface active ionic liquid[C₁₂MIm]Br has been choose optimally to test the contact angle between its solution and coal dust,showing that the contact angle between the ionic liquid solution and coal dust was smaller than that between coal dust and deionized water which[C₁₂MIm]Br solution had the smallest contact angle of and the strongest effect on wetting coal dust.Finally,the modification effect of ionic liquids of[HOEt MIm][NTf2]and[C₁₂MIm]Br on the wettability of coal dust with three different coalification degrees of lignite,bituminous coal and anthracite was analyzed,and the contact angles of the coal dust samples treated with two ionic liquid solutions and deionized water and two ionic liquid solutions were tested.And the results shown that the ionic liquid treatment was not conducive to the enhancement of wettability of lignite,but had a significant effect on the enhancement of wettability and solution absorbability performance of bituminous coal and anthracite coal.By infrared spectroscopy and X-ray photoelectron spectroscopy,it was found the hydrophilic groups increased and hydrophobic groups decreased on the face of coal dust samples treated with solutions and some ionic liquid remained on the surface of coal sample enhancing the wettability.In general,the effect of wettability of coal dust under the action of[C₁₂MIm]Br had the most significant enhancement.There are 35 figures,16 tables and 106 references in this paper.