宁东煤田中部侏罗纪煤的矿物学特征

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。

Mineralogical of the Jurassic coals in the middle of Ningdong Coalfield

26 samples，including 25 coal-seam samples and one parting，were collected from 7 mines in NingdongCoalfield，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 Ningdong Coalfield is a medium volatile bituminous coal，with medium-ash，low-sulfur and low-medium calorific，the mineral 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，chamosite，quartz，and albite are origin from weathering productions of gneiss，granulite and granite in HelanMoutain.