宁东煤田中部侏罗纪煤的矿物学特征

Mineralogical of the Jurassic coals in the middle of Ningdong Coalfield

样品采自鄂尔多斯盆地西部宁东煤田的7个井田,共26个样品,包括25个煤样和1个矸石样。对所采的25个煤样做了工业分析、全硫分析和发热量分析,并运用低温灰化-X射线衍射(LTA-XRD)仪、光学显微镜、扫描电镜(SEM)以及能谱仪(EDS)等设备对样品矿物成分、化学成分、微形貌特征等方面进行了研究,探讨了煤中矿物的物质来源。研究表明,宁东煤田中部侏罗纪煤属中等挥发分煤,具有中灰、低硫、中低发热量的特征,其(低温灰化后)矿物组成为:33.1%高岭石、22.8%伊利石、21.5%石英、13.2%钠长石、6.6%鲕绿泥石、2.8%方解石。另外在扫描电镜下还发现了极少量的黄铁矿、菱铁矿、钛铁矿、黄铜矿、锆石。高岭石、伊利石、鲕绿泥石、石英、钠长石源自贺兰山脉片麻岩、麻粒岩和花岗岩的风化产物。

26 samples, including 25 coal-seam samples and one parting, were collected from 7 mines in Ningdong- Coalfield, Ordos Basin, China. Proximate, total sulfur and gross calorific value were analyzed of the 25 coal samples. The composition, chemical composition and micro-topography of samples were studied by low-temperature ashing-X-ray diffraction （LTA-XRD） ,optical microscopy,scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）. The sources of minerals in coal were discussed. The results indicate that Jurassic coal in middle part of Ning- dong Coalfield is a medium volatile bituminous coal, with medium-ash,low-sulfur and low-medium calorific, the miner- al composition （ low temperature ashes） is as follows ：33.1% kaolinite,22.8% illite,21.5% quartz, 13.2% albite, 6.6% chamosite,2.8% calcite. In addition, a trace of pyrite, siderite, ilmenite, chalcopyrite, zircon also found by the scanning electron microscope. Kaolinite, illite, ehamosite, quartz, and albite are origin from weathering productions of gneiss,granulite and granite in HelanMoutain.