准噶尔煤田阜康矿区小黄山煤矿煤的矿物学特征

Mineralogical characteristics in No.6 coal seam from Xiaohuangshan Coal Mine of Fukang Mining Area,Junggar Coal Field

煤中矿物类型及组合特征对煤炭的加工利用具有重要意义,其决定了煤在燃烧、气化、液化等方面的性质。为了使准噶尔盆地阜康矿区的煤炭资源得到清洁高效利用,采集发育在小黄山煤矿6号煤的11个样品,对其进行工业分析、全硫分析和发热量分析,运用X射线荧光光谱、低温灰-X射线衍射、电子探针对煤灰中的常量元素、煤中的矿物进行了分析,并研究其成因。研究结果表明:小黄山煤矿6号煤层属中高挥发分、特低灰分、特低硫,特高热值煤。煤灰中Na_(2)O相对质量分数为10.91%,具有顶部和底部高中部低的特征,分析表明煤中的矿物并非Na的主要来源,煤中的Na部分可能来自于表土层中的Na,地表水在下渗透过程中将其带入到煤层中,部分可能来源于中生代地层中具有超压的Na_(2)SO_(4)型水。低温灰化后主要矿物组成为白云石、片钠铝石、石英、钠长石、黏土矿物、方解石及少量的磷灰石、针铁矿等。片钠铝石是由煤化过程中产生的CO_(2)与硅铝酸盐矿物反应形成,白云石和方解石作为后生矿物由煤化过程中产生的CO和CO_(2)与赋存在煤中的流体反应形成。磷灰石作为后生矿物由热液活动或者是有机物分解过程释放出的磷在适当的化学条件下再沉淀形成,针铁矿为煤中铁的硫化物被氧化形成。

Minerals in coal are of great significance in determining coal properties,washing,combustion,gasification and liquefaction.In or⁃der to realize the clean and efficient utilization of coal resource in Fukang,11 coal samples were collected from Xiaohuangshan Mine in Fu⁃kang area.Proximate,total sulfur and gross calorific value were analyzed for these coal samples.The composition,and micro-topography of samples were studied by X-ray fluorescence(XRF),low-temperature ashing-X-ray diffraction(LTA-XRD)and electron probe microana⁃lyzer(EPMA).The results indicate that the No.6 coal of Xiaohuangshan Mine are characterized by low moisture,medium-high volatiles,low ash,and low sulfur coals.The average content of Na_(2)O in the ash of No.6 coal seam samples was 10.91%,which was characterized by high content of Na_(2)O in the top and bottom coal seams and low content of Na_(2)O in the middle.The analysis showed that the minerals in coal were not the source of Na.Part of the Na in the coal may come from the topsoil,which was carried into the coal seam by the surface water in the process of infiltration.The other part may come from the overpressured Na_(2)SO_(4)water in Mesozoic strata.The mineral composition(low temperature ashes)is as follows:dolomite,dawsonite,quartz,albite,clay minerals,and calcite.In addition,a trace of apatite and gogethite also found by the electron probe microanalyzer.It is speculated that during the peat depositional period,silicate minerals were carried to the peat swamp by water and reacted with CO_(2)released from the coalification process to form dawsonite.Dolomite and calcite in coal are formed from CO and CO_(2),which are produced from coalification process,reacting with the fluid in coal.The apatite may either be formed by migration of hydrothermal solutions or from local remobilization of phosphate,formed earlier within the coal seam or associated strata.Gogethite is the oxidation product of iron sulfides in coal.