Effect of stacking structure on the wettability of coal dust based on X-ray diffraction experiment

To investigate the effect of stacking structure on the wettability of coal dust,ten selected coal samples from China's different regions with different metamorphic grades were analyzed by X-ray diffraction. In combination with the dynamic contact angle determination results of the liquid-solid interface,the relationship between microcrystalline parameters and the wettability of coal dust was deduced. The results show that the inorganic mineral types gradually decrease with increasing metamorphic grade,and the more the primary mineral types are,the better the wettability of coal dust is,but the secondary minerals have no significant influence on the wettability of coal dust. For different coal types,the higher the metamorphic grade of coal is,the more the crystalline component is,the bigger the structural unit of aromatic microcrystals is,and the higher the aromatic ring condensation degree will be. While the coals with low-medium metamorphic grades have more amorphous components,which include hydrophilic alkyl side chains of small molecules,oxygen-containing functional groups,etc. With increasing stack degree and spread degree,the plane spacing decreases gradually,and the wettability of coal dust becomes worse. When the stack degree is 18.5 nm,the spread degree is 41.7 nm and the plane spacing is 0.898 nm,the wettability of coal dust will be the best. The closer the X-ray diffraction microcrystalline parameters are to the above combinations,the better the wettability of coal dust is.