Geochemical Characteristics And Formation Environment Of Rich Inertinite Coal In Hujiahe Mine

Due to its special high-carbon and macromolecular carbon network structure and natural inertia,the study of higher inertinite content coal is of great significance not only for the comprehensive utilization of coal resources,but also as a good evidence of catastrophic geological events.In this project,No.4 coal of Hujiahe Mine in the southern edge of ordos basin was selected as the research object,guided by the theories of coal geology,petrology,mineralogy and element geochemistry.By using the polarization microscope,XRD,XRF,ICP-MS,SEM-EDS techniques,28 samples of Hujiahe mine were tested and analyzed,and then the geochemical characteristics of No.4 coal in Hujiahe Mine were studied and its formation environment was discussed.The composition of coal,the glossiness for bitumen-grease,in No.4 coal of Hujiahe Mine is mainly dark coal,followed by bright coal.The microstructures of the No.4 coal were dominated by inertinite(66.97%),vitrinite(30.00%)and exinite(2.60%)were less.No.4 coal in hujiahe mine is of high quality coal with super low ash,high volatile content,super low sulfur and super high calorific value.The XRD spectrum showed that mineral mainly consists of quartz,kaolinite,calcite,dolomite,ankerite and pyrite.In addition,apatite,microcline,rutile,illite,sodium feldspar,zircon,strontianite,siderite and galena was also found by the SEM-EDS.The total content of constant elements in No.4 coal of Hujiahe Mine is not greater than that of China.The total content of trace elements in coal showed a loss,and only Pb element was slightly higher than the background value of world bituminous coal.The content of rare earth elements and the total amount of REY in coal are all lower than that of the United States,China,world and clark values.The light rare earth elements in no.4 coal are relatively enriched,and the overall performance is rich light and medium rare earth elements.According to the study on the coal facies of No.4 coal and the sensitive elements with indicating significance to the environment,it can be concluded that the coal of the rich inertinite in Hujiahe Mine belongs to inland facies sedimentation,and the coal forming environment is a dry oxidizing environment,and there may had been forest fire.The coal facies of No.4 is in dry forest peat swamp,the whole peat swamp is higher than the land diving surface,the water body is fresh water,and the hydrodynamic conditions of peat mire are weak and coal-forming plants were mainly woody plants.