关键词: 核磁共振, X射线光电子能谱, 粉体, 化学分析, 润湿性

Abstract: In order to analyze the low wettability about the bituminous coal dust with medium metamorphic grade from the microscopic aspect, taking Zhaolou gas-fat coal in Juye coalfield as the example, the methods of nuclear magnetic resonance and X-ray photoelectron spectroscopy were utilized to achieve the microscopic molecular structures, and the molecular parameters' influence on the wettability was investigated. According to the experimental results, the aromatic degree of the coal dust in Zhaolou mine was 0.77, and the content of aromatic structure was large, which mainly contained protonated aromatic ring. Moreover, chain alkanes and cycloalkanes side chains held the most part of aliphatic chain structures, also some methyl side chains were included. Ether group (C—O—C) was the first superficial oxygen-containing functional group of coal dust in Zhaolou mine. The second was carbonyl (C=O). The third was hydroxy (C—OH). The last was carboxyl (COOH). Moreover, the content ratio of the above four groups was about 4:2:2:1.5. Not only the aromatic degree of the coal dust was high, the size of aromatic cluster was large and the condensation degree was high, but also the alkyl side chains were few and short, which made the coal's molecular structure unit shows a strong hydrophobicity. However, the carboxyl (COOH) and hydroxy (C—OH), which contributed much to the surface hydrophilicity, only held 13.53% and 21.45% of the whole content of superficial oxygen-containing functional groups, respectively. Therefore, influenced by microscopic molecular structures, the coal dust of Zhaolou mine showed an overall characteristic of hydrophobicity and poor wettability.

Key words: NMR, XPS, powder, chemical analysis, wettability