Structure of the organic crystallite unit in coal as determined by X-ray diffraction

X-ray diffraction （XRD） was used to study the structure of the organic crystallite unit （La, Lo doo2） in coals collected from Henan and Shanxi Provinces. XRD patterns of coal were collected in a step-scan mode （0.1 °/step） over an angular range of 2-90° （20）, allowing 8 s at each step. The structure of the crystallite unit was determined from the Scherrer equation and peak parameters deduced from whole pattern fitting. The results show that the structure of the crystallite unit in coal is mainly controlled by the coal rank. As the coal rank increases the average diameter of a coal crystallite unit （La） increases, the interlayer spacing （doo2） decreases slightly, and the average height of a coal crystallite unit （Lc） increases at first but then decreases. A new diffraction peak from the crystallite unit in coal was found at a low scattering angle in the XRD pattern （2-10~）. This suggests a structure with an inter-layer spacing from 1.9 to 2.8 nm exists in coal crystallites.

具有膨胀特性膏体充填材料的物理力学特性研究

针对煤矿采空区膏体充填材料无法充分接顶的现状,运用X射线衍射仪(XRD)及X射线荧光光谱分析仪(XRF)对膨润土、煤矸石、粉煤灰等膏体充填材料进行化学物相分析,结合自制的膨胀测定仪器,分析检测不同膨润土掺入比的膏体材料膨胀率随时间的变化关系,并对不同养护龄期下的膏体试件进行力学性能测试与微观水化机理研究。结果表明:配比P04为最优配比,即胶结料∶膨润土∶煤矸石∶粉煤灰为1∶0.6∶3∶4,质量浓度为72%,28d单轴抗压强度为4.85 MPa,膨胀率为2.25%。P04膏体衍射谱图表明,不同龄期的水化产物各物质含量各不相同,在水化初期8h内即生成一定量的钙矾石,28d生成大量的C-S-H凝胶。