不同化学预处理对神府煤粉孔隙结构特征的影响

Different Chemical Pre-Treatment Affected to Pore Structure Features of Shenfu Fine Coal

为给制备煤基纳米复合材料提供参考,对利用酸脱灰、碱脱腐植酸、空气氧化3种化学预处理方法制备的神府脱灰煤样、脱灰脱腐植酸煤样和脱灰氧化煤样,采用低温液氮吸附试验对各煤样的孔隙结构特征进行了研究。结果表明:酸脱灰、碱脱腐植酸、空气氧化处理对煤粉的孔径分布有明显影响,化学预处理后煤粉的总孔容和比表面积均减小,平均孔径增大,各孔径段孔隙数量减少,其中微孔数量减少最为明显。化学预处理过程对煤样的孔隙类型影响较小,原煤样和预处理煤样均以一端封闭的不透气性孔为主。神府煤粉经过以上3种化学方法处理后,其比表面积和孔体积分形维数均减小,孔隙结构特征得以改善,煤粉孔隙系统复杂程度降低,更适合作为制备煤基功能复合材料的基体。

In order to provide the references for the preparation of the coal base nanocomposite,three chemical pre-treatment methods,in- cluding the ash removed method with acid, humic acid removed with alkali and air oxidization were applied to prepare the ash removed coal sample, ash and humic acid removed coal sample and ash removed oxidized coal sample from Shenfu coal and a study on the pore struc- tures of each coal sample was conducted with cryogenic liquid nitrogen adsorption experiment. The results showed that the ash removing with acid, humie acid removing with alkali and air oxidized treatment would remarkably affect to the pore diameter distribution of the fine coal.After the chemical pre-treatment,the total pore volume and the specific surface area of the fine coal both would be reduced,the aver- age pore diameter would be increased, the pore number at each pore diameter section would be reduced and the number of the micro pores would be reduced obviously.The chemical pre-treatment process would have less influence to the pore types of the coal sample and the raw coal sample and the pre-treated coal sample were all mainly non permeability pore with one end closed.After above three chemical treat- ments of the Shenfu fine coal, the specific surface area and the pore volume fractal dimension both would be reduced, the pore structure features would be improved, the complexity of the fine coal pore system would be reduced and the fine coal would be more suitable to pre- pare the coal based functional composite.