Occurrence Characteristics And Enrichment Mechanism Of Germanium And Gallium In Coal

With the depletion of traditional rare metal deposits,coal-bearing associated metal deposits have received much attention.The western region is an important energy resource connection area in China,and the associated elements in coal has also attracted attention.However,the distribution law and enrichment mechanism of beneficial metal deposits in coal are still unclear.In addition,with the development of large coal bases in the western region,the accumulation of huge quantities of coal gangue has increased year by year due to low comprehensive utilization rate,which has increased the burden of ecological environment.In response to the above scientific problems,this thesis is comprehensively applied the theories of geology,petrology,mineralogy and geochemistry,using polarized light microscopy,XRD,XRF,ICP-MS and SEM-EDX analysis methods,taking the Muli and Zhundong coalfields as the research object,and focusing on the occurrence characteristics and enrichment mechanism of germanium and gallium in coal.The following innovative results have been achieved:The distribution characteristics of the beneficial element gallium in coal of Qinghai Muli and Xinjiang Zhudong coalfields are clarified.It is found that the Ga content in the eastern coal is higher than that in the central and western regions of Muli coalfield,and the Ga is enriched in the Chaidaer and Qugugou coal mines samples.The Ga content is higher in the northeastern and southwestern parts of the Zhundong coalfield.the Ga element is mainly present in Aluminosilicate minerals(mainly kaolinite)with a certain affinity with organic matter in coal.It reveals the enrichment characteristics of the beneficial elements Ga and Ge in coal in the coal-producing area of Northwest China and divides the favorable area of metallogenesis.It is found that the abnormal distribution area is mainly in the Zhundong coalfield,the average content of Ga reaches the cut-off grade(30?g/g)in the coal samples of Zhundong coalfield.The average content of Ge in coal is close to the cut-off grade(20?g/g).Some mining areas have Ga anomalies in the Muli coalfield in Qinghai,but they are mainly concentrated in the top,bottom and parting of coal seams.The enrichment mechanism of the beneficial element gallium in coal in the study area is revealed,and the metallogenic model of associated with coal and gallium is proposed.The enrichment of Ga in coal is mainly controlled by the properties of the parent rock in the terrestrial area,coal-forming plants,peat bog water medium conditions,paleoclimate conditions and source transport form.The migration and enrichment of trace element Ga is controlled by the major element Al,and the weathering of Al-riched volcanic rock produces a positively charged Al(OH)₃colloid,which is carried by the water flow to the peat swamp and coagulined with the negatively charged colloidal Si O₂and humic acid,resulting in the enrichment of Ga in coal.The research achievements provide a scientific basis for the comprehensive utilization of coal resources and the large-scale disposal in the western China.