Geochemical Characteristics Of NO.4 Coal In Mengcun Mine

This paper takes the No.4 coal of Mengcun Coal Mine in Binchang Mining Area as the research object.Guided by knowledge theories such as coal petrology,mineralogy,and inorganic geochemistry,industrial analysis,total sulfur analysis and calorific value analysis were performed on the samples taken.Using the experimental instruments,such as inductively coupled plasma mass spectrometry?ICP-MS?,optical microscopy,low temperature ashing-X-ray diffractometry?LTA-XRD?,X-ray fluorescence spectrometry?XRF?,scanning electron microscopy?SEM?and and energy dispersive spectroscopy?EDX?.The mineralogical characteristics,coal petrological characteristics,trace element characteristics and organic geochemical characteristics of the samples were studied.The results show:No.4 coal in Mengcun Coal Mine is mainly semi-dark coal and dark coal.Asphalt luster,stepped fracture,strip-like structure,hard and brittle.The microscopic components of the sample were dominant in the inert group?71.05%?,the vitrinite group?27.90%?was less,and the chitin group?1.05%?was the least,the rest were clay minerals.The coal-forming environment is a dry oxidizing environment,and the peat swamp type is a dry forest peat swamp.The groundwater dynamic conditions are weak,and the coal-forming plants are mainly woody plants.The main mineral types in No.4 coal of Mengcun Coal Mine include clay minerals,carbonate minerals,sulfide minerals and oxide minerals.The clay minerals are mainly kaolinite.It is observed in the microscope that the clay minerals are mostly disseminated in the matrix vitrinite,or in the cell filling state in the silky body.The carbonate mineral is mainly calcite,and the calcite is usually distributed in veins or filled in the organic cell cavity.Sulfide minerals are mainly pyrite,mostly tuberculous,occasionally filled with cells.Oxide minerals are mainly quartz,occasionally rutile.Quartz is mainly composed of terrestrial quartz crumbs,sub-angular,associated with finely dispersed clay minerals or distributed in matrix vitrinite.Rutile is often distributed in the matrix vitrinite or interstitial space with granular aggregates,often associated with clay minerals and pyrite.The average content of the constant elements in the sample is lower than the background value of the element content in Chinese coal.Except that the Na₂O content is within the normal range,the other constant elements are in a loss state.Except for the normal content of Sr and Ba in Mengcun No.4 coal seam,the other elements are in a loss state.The content of rare earth elements contained in the sample is lower than the Chinese value,the world value and the upper crust value,indicating that the rare earth elements in the study area are relatively depleted.Comprehensive judgment of various parameters of rare earth elements is rich in light rare earth.