Effects of the changes in interfacial properties of lignite under microwave irradiation on its slurry ability

Under a 900 W microwave power, the effects of different microwave irradiation times on the interfacial properties of lignite were investigated, the impact of these changes on lignite slurry ability was studied, and the changes in the oxygen-containing functional groups, pore structures, surface morphology and fractal dimension were also investigated through low-temperature nitrogen gas adsorption (LT-N₂GA), chemical titration method and scanning electron microscopy (SEM).The results show that with the increase of microwave irradiation time, the moisture content and dehydration rate of the coal samples gradually decrease; the content of oxygen-containing functional groups also dropp; the specific surface area of coal samples increase and then gradually reduce; the average pore diameter and pore volume decrease and then gradually increase; the surface of coal particles tended to be smooth and the fractal dimension decrease.All these changes contribute to the improvement in the lignite slurry ability, for example, the maximum solid loading of lignite increases from 51.3% to 54.6% after microwave irradiation for 12 min.