酸洗脱灰处理对新疆和丰低阶煤结构和萃取性能的影响

对新疆和丰低阶煤样进行酸洗脱灰处理，通过相关表征，分析了脱灰处理对煤样主体结构、石油醚和CS₂萃取性能的影响。FT-IR表征表明，煤样经酸洗脱灰处理，结构仅发生了微弱改变，酸洗煤样（AC）仅在1712 cm^-1处出现了较弱的原煤样（RC）所没有的羧酸类C=O吸收峰。由TG-DTG表征可知，酸洗使得煤中小分子键断裂，但并未破坏煤样的大分子网络主体结构。以石油醚（PE）和CS₂为溶剂对RC和AC两煤样进行常温两级超声萃取的研究表明，AC煤样的PE和CS₂萃取率均高于RC煤样，分别从0.16%和0.53%（RC煤样）增加到0.17%和0.64%，且萃取速率也更大，显著降低了煤样的溶剂萃取次数。萃取物的FT-IR和GC-MS分析表明，酸洗处理不仅能有效脱除煤样中的杂原子，且使得煤样CS₂萃取物的种类增加。另外，由萃余物TG-DTG结果可知，超声萃取主要是一个物理溶胀过程，并没有破坏煤样的大分子主体结构。

Influence of acid treatment on the structure and extraction performance of Xinjiang Hefeng low-rank coal

The acid treatment experiment to remove the inorganic minerals in Xinjiang Hefeng low-rank coal was conducted, and the effects of deashing treatment on the main structure of coal sample and its extraction performance by petroleum ether and CS₂ were analyzed by instrumental characterizations. The FT-IR results show that the main structure of the treated coal changes slightly compared with the untreated one. And the acid-washed coal sample (AC) presents a very weak absorption peak at 1712 cm^-1 attributed to carboxylic acid (C=O), which could not be observed in the raw coal sample (RC). It can also be seen from TG-DTG characterization that the process of acid treatment results in a cleavage of small molecular bonds in the coal without destroying the macromolecular network structure. The performance of two-stage ultrasonic extraction of RC and AC samples with petroleum ether (PE) and CS₂ as solvents proposes that the extraction proportions of PE and CS₂ of AC sample are higher than that of RC sample, from 0.16% and 0.53% (RC) to 0.17% and 0.64%, respectively, and the extraction rate of AC sample is larger than that of RC sample, reducing the number of solvent extraction operation significantly.FT-IR and GC-MS analysis of the extracts shows that the acid treatment not only effectively removes the heteroatoms in the coal sample, but also increases the type of CS₂ extracts. In addition, from the results of TG-DTG for the residues, it can be noted that the ultrasonic extraction is a physical swelling process, and does not destroy the macromolecular structure of the coal sample.