【作者】 王文龙；

【导师】 王文峰；

【作者基本信息】 中国矿业大学 ， 地球化学， 2021， 硕士

【摘要】 煤中有害微量元素在利用过程中的迁移特性与其含量和赋存状态密切相关。伊犁盆地作为新疆规划的四大煤炭基地之一,进行煤中有害微量元素相关研究对区内煤洁净化利用具有重要意义。本文利用工业分析、全硫分析、电感耦合等离子体质谱法、原子荧光光谱、扫描电镜能谱分析等测试手段,对盆地南北缘西山窑组煤的煤岩煤质特征、矿物种类、有害微量元素含量进行了研究。综合煤地球化学、矿物学、统计学、沉积学的相关知识,对有害微量元素赋存特征、时空分布及地质控制因素进行了讨论。主要得到以下成果认识:(1)明确了伊犁盆地西山窑组煤的煤岩、煤质与矿物学特征。西山窑组煤呈现特低灰-低灰、中高挥发分-高挥发、特低硫-低硫的特点,煤化作用较低。煤显微组分以惰质组为主,镜质组次之,壳质组和矿物组占比较少。盆地北缘皮里青矿煤中矿物主要有黄铁矿、方解石、菱铁矿、石英、粘土矿物、锆石等;盆地南缘腾达矿煤中主要矿物为石膏、粘土矿物、石英、铁氧化物、含铁硫酸盐矿物等。(2)揭示了伊犁盆地西山窑组煤中有害微量元素的分布特征。西山窑组煤有害微量元素含量低于或接近中国煤和世界煤。盆地南缘与砂岩型铀矿眦临的腾达矿部分有害微量元素呈轻度富集,以中国煤中含量值为基底,Ni、As、Mo富集系数值为2.01、3.86、2.11;以世界煤中含量值为基底,Ni、Mo、Hg富集系数CC为2.11、2.95、2.25;盆地北缘远离砂岩型铀矿床的皮里青矿煤中各有害微量元素富集系数均低于2。西山窑组煤中有害微量元素含量高于八道湾组煤,与砂岩型铀矿有空间联系的煤中U、Mo、Cr、As、Ni、Se呈“轻度富集-异常富集”特征,显著高于未受影响的煤层。(3)揭示了研究区煤中有害微量元素的赋存特征。有害微量元素与煤中矿物组成关系密切,腾达矿有害元素矿物结合态比重高于皮里青矿。皮里青矿有害微量元素主要以盐酸溶态、有机结合态、硫化物结合态、硅铝酸盐结合态赋存;V、Co、U主要以盐酸溶态赋存,Th主要以硅铝酸盐结合态赋存,硫化物结合态是Cu的主要赋存形式。腾达矿有害微量元素赋存状态以硫化物结合态、离子交换态、盐酸溶态、有机结合态为主,占比均接近90%;V、Co、Ni、Cu、Zn、Ba、Pb主要以硫化物结合态赋存,Cr、Tl、Th主要以离子交换态赋存,Cr、Mo、Cd以有机结合态赋存的比例显著,U主要以盐酸溶态、硫化物结合态赋存。(4)阐述了影响研究区煤中有害微量元素分布赋存的主控地质因素。盆地西山窑组整体上为干旱森林沼泽条件下形成的含煤地层。较弱的水动力条件、稳定的泥炭堆积速率、酸性水体对泥炭沼泽中矿物质的溶出作用使得煤样呈现低灰低硫的特点。表生热液对煤层的叠加改造是腾达矿有害微量元素含量高于皮里青矿主要原因。成煤环境、陆源碎屑供给、表生热液作用、地下水作用是伊犁盆地各时代、各区域煤中有害微量元素赋存差异性的主控地质因素。更多还原

【Abstract】 The migration characteristics of hazardous trace elements in coal are closely related to their content and occurrence during utilization.Yili Basin is one of the four coal bases planned in Xinjiang.It is of great significance to study the hazardous trace elements in coal for the clean utilization in the region.In this paper,by means of industrial analysis,total sulfur analysis,ICP-MS,AFS,SEM analysis and other testing methods,the characteristics of coal rock and coal quality,mineral types and contents of trace hazardous elements of the Xishanyao Formation coal in the northern and southern margin of the basin were studied.Based on the knowledge of coal geochemistry,mineralogy,statistics and sedimentology,the occurrence characteristics,spatial and temporal distribution and geological control factors of hazardous trace elements were discussed.The main achievements are as follows:(1)The characteristics of coal rock,coal quality and mineralogy of Xishanyao Formation in Yili Basin were defined.The coal of Xishanyao Formation is characterized by ultra-low to low ash,medium-high to high volatile matter,ultra-low to low sulfur and low coalification.The coal macerals are dominated by inertinite,followed by vitrinite,exinite and mineral.The main minerals of Piliqing coalfield in the northern margin of the basin are pyrite,calcite,siderite,quartz,clay minerals,zircon,etc.The main minerals of Tengda coalfield in the southern margin of the basin are gypsum,clay minerals,quartz,Feoxides,Fe-bearing sulfate minerals,etc.(2)The distribution characteristics of hazardous trace elements in coal of Xishanyao Formation in Yili Basin were revealed.The contents of hazardous trace elements in coal of Xishanyao Formation are lower than or close to those of Chinese coal and world coal.Some hazardous trace elements of Tengda coalfield in the southern margin of the basin,which is close to the sandstone-type uranium deposits,are slightly enriched,and the Concentration Coefficient(CC1=Sample/Chinese coal)of Ni,As and Mo are 2.01,3.86 and 2.11 respectively for Chinese coal,and the Concentration Coefficient(CC2=Sample/World coal)of Ni,Mo and Hg are 2.11,2.95 and 2.25 respectively for Chinese coal.Concentration Coefficient(CC)of all hazardous trace elements of Piliqing coalfield in the northern margin of the basin,which is far away from sandstone-type uranium deposits in the southern basin,are lower than 2.The content of hazardous trace elements in the coal of Xishanyao Formation is higher than that in the coal of Badaowan Formation.The contents of U,Mo,Cr,As,Ni and Se in the coal with spatial connection with sandstone-type uranium deposit show the characteristics of "slightly enriched to abnormally enriched",which is significantly higher than that in the coal seam without influence.(3)The occurrence characteristics of hazardous trace elements in the coal of study area were revealed.There is a close relationship between the hazardous trace elements and the mineral composition in the coal,and the proportion of the hazardous elements bonded to minerals in Tengda coalfield is higher than that in Piliqing coalfield.The occurrence states of hazardous trace elements in Piliqing coal are mainly hydrochloric acid dissolved state,organic bound state,sulfide bound state and silicate aluminate bound state.V,Co and U mainly occur in the dissolved form of hydrochloric acid,Th mainly occur in the combined form of silicate aluminate,and Cu mainly occur in the combined form of sulfide.The main occurrence states of hazardous elements in Tengda coalfield are sulfide bound state,ion-exchange state,hydrochloric acid dissolved state and organic bound state,accounting for nearly 90%.V,Co,Ni,Cu,Zn,Ba and Pb mainly occur in sulfide bound state,Cr,Tl and Th mainly occur in ion-exchange state,Cr,Mo and Cd mainly occur in organic bound state in significant proportion,U mainly occurs in hydrochloric acid dissolved state and sulfide bound state.(4)The main geological control factors affecting the distribution and occurrence of hazardous trace elements in coal of study area were expounded.The Xishanyao Formation in Yili basin is a coal bearing stratum formed under the condition of arid forest-swamp.Weak hydrodynamic conditions,stable peat accumulation rate and acid water dissolution of minerals in peat swamp make the coal samples appear low ash and low sulfur.The superimposed modification of coal seam by superthermal fluid is the main reason that the content of hazardous trace elements in Tengda coalfield is higher than that in Piliqing coalfield.Coal-forming environment,terrigenous detritus supply,superthermal fluid action and groundwater are the main geological factors controlling the difference of occurrence of hazardous trace elements in coal of different regions and ages in Yili basin.更多还原