Study on wettability model of coal particles based on composition

In order to assess coal floatability, it is necessary to understand how different coal compositions affect particle-wetting behavior. In this study, the influence of different sizes and densities of particles on coal wettability was conducted, respectively. For this purpose, the coal compositions were explored via XRF and the wetting rising velocity experiment of each coal composition was investigated based on the capillary force. The contact angle decreases obviously with the decrease in particle size. The contact angle decreases as the coal particle density increases. The larger the contact angle, the worse the wettability. The coal compositions had a significant effect on the coal-wetting behavior. The content of organic substances decreased with the decrease in powder size. SiO2 had the highest content and the lowest contact angle among the inorganic oxygen-containing. Hydrogen bonds were created between the hydrogen and oxygen atoms on the surface. The stronger the hydrogen bonding force, the more tightly the water molecules adsorbed. Furthermore, the organic content decreased as the coal density increased. The increase in contaminants could be responsible for this phenomenon. The predictive wetting model between the coal compositions and the contact angle was established and its accuracy was evaluated. The predictive model is reliable at larger coal sizes and lower densities due to an average error at 7.2% of 0.35 mm and 10.61% of 1.35 g/cm3. The results provide some valuable insight into the efficient clean utilization of technology and pre-flotation feedback for coal processing.