褐煤经微波改性后界面性质的变化对其成浆性的影响

在900 W功率下考察了不同微波辐照时间对褐煤界面性质的影响,同时考察了这些变化对褐煤成浆性的影响。利用化学滴定法、低温氮吸附法和扫描电镜,探讨了煤样的表面含氧官能团、孔隙结构、表面形貌及分形维数在微波辐照后的变化。试验结果表明:随着微波辐照时间的增加,褐煤的含水率及脱水速率逐渐降低;褐煤表面含氧官能团含量逐渐降低;煤样的比表面积先升高后逐渐降低,平均孔径和孔体积均先降低然后再逐渐升高;煤粒表面逐渐趋于平整光滑;煤样孔隙的分形维数逐渐减小。将这些煤样制浆后发现褐煤的定黏浓度由原煤的51.3%上升到微波辐照12 min时的54.58%。

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-N2GA),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.