Distribution And Enrichment Characteristics Of Beneficial Trace Elements Of Coal In Datong Mining Area

The study of beneficial elements in the coal has great significance for the development and utilization of these elements.In this paper,172 samples from 23 mining areas and 3 outcrops in Datong mining area were subjected to ICP-MS,XRD analysis,sequential chemical extract and other experiments to study the content,enrichment feature and occurrence characteristics of beneficial elements in coal in this area.(1)Revealed the distribution law of beneficial trace elements in coal in Datong mining area.The content of Li,Ga,Th,Sr,La,Ce,Er,Rb,Sc,and U in Datong mining area are higher than those in Chinese coal,and the content of Cs,V,Ge,Pr,Nd,Sm,Eu,and Gd of coal in Datong mining area is lower than that in China.The content of Li,Ga,Th,Sr,V,U and REE in Datong mining area is higher than that in the world coal,and the content of Rb,Cs,V,Ge in Datong mining area is lower than that in the world coal content.The overall content of beneficial elements such as Li and Ga in Shan No.4,No.5,No.3-5 and No.3 coal seams gradually decreased;the overall distribution of REE was contrary to it;Li,Ga,Th,U,V and Sr,Tm,Yb,Y,Ho,Er,Lu,Tb,Dy,Sc are higher in the Carboniferous-Permian than in the Jurassic,and the distribution of other elements is opposite;the Datong mining area presents HREE Enrichment,LREE loss status.(2)Clarified the occurrence state of beneficial trace elements in coal in Datong mining area.In this paper,the six types of beneficial elements in coal are analyzed through a stepwise chemical extraction experiment.The results show that: in the water-soluble state,except Co,the content of other elements is less than 10%;in the ion-exchange state,except Ni,In addition to the four elements Rb,Sr,and Cs,the content of the remaining elements is less than 10%;in the carbonate-bound state,except for the elements of V,Co,and Ga,the content of the ion exchange state of the remaining elements is less than 10%;In the combined state,the content of Co element exceeds 20%,the content of V,Sr,U element exceeds 10%,and the content of other elements is less than 10%;in the silicate combined state,except for Co element,the remaining elements The content of bound state of silicate exceeds 20%;in the residual state,the residual state content of all elements is higher,and the residual state content of Ni,Gs,Rb,Sr,U exceeds 30%.Correlation analysis and cluster analysis results show that the four elements Th,U,Ga,Li are mainly present in clay minerals and organic matter,and some may be present in sulfate minerals and carbonate minerals;V,Sr elements are mainly present in Clay minerals and organic matter;Rb,Cs,Ge,Co,Ni elements are mainly present in clay minerals and organic matter,and a small amount is present in sulfide and carbonate minerals.(3)The enrichment characteristics and enrichment factors of beneficial trace elements in coal in Datong mining area are revealed.The enrichment degree of Ga and Th in coal in Datong mining area is higher than that in Chinese coal,and the remaining elements are not enriched.The enrichment degree of Li,Ga,Th,Y,La,Ce,Er,and Yb in coal in Datong mining area is higher than that in the world,and the enrichment degree of other elements is not.Li,Ga,Th,U,V,Sr and rare earth elements as a whole are deficient in the Jurassic strata compared to the Carboniferous-Permian strata;Rb,Cs,Ge,Co,Ni are relatively less carboniferous in the Jurassic strata-The Permian stratum is rich in content.The accumulation factors of beneficial trace elements in coal in Datong mining area mainly include sedimentary material sources,paleogeographic depositional environment,tectonism,magmatism and organic matter.