Study On Geological Characteristics And Enrichment Mechanism Of REE In Xinmin Bauxite Deposit In Northern Guizhou Province

As one of the world's bulk minerals,bauxite and its associated resources have been studied by scholars in different fields?geology,industrial extraction and commercial utilization?.However,in the geological field,there are few reports on the homology of Al and REE,and the coupling relationship between the distribution of rare earth in the ore-bearing rock series and the geological characteristics of the direct roof and floor.Based on the understanding of the previous work,the Xinmin bauxite deposit in the North of Guizhou province is selected.By means of thin section identification,scanning electron microscopy,X-ray analysis?XRD?,electron probe and geochemistry,the geological characteristics and enrichment mechanism of rare earth in Xinmin bauxite deposit in Northern Guizhou province were studied.It focuses on whether Al and REE in Xinmin bauxite deposit have homology,and the influencing factors of rare earth bottom enrichment in ore-bearing rock series.Based on the above methods and internal data,combined with the previous research results,the following understanding is mainly obtained.In terms of rare earth enrichment geological characteristics,the spatial enrichment location of rare earth in the ore-bearing rock series is closely related to the thickness,distribution area and sedimentary environment of the karst palaeogeomorphology and ancient drainage basin of the direct floor,and the carbonaceous mudstone or inferior coal line of the direct roof.With the enhancement of weathering,in the evolution process of"source rock?mineralized geological body?various types of bauxite",rare earth enrichment in the early stage and loss in the later stage.Although in each type of bauxite,the enrichment characteristics of rare earth are slightly different.However,in the same type of bauxite,the total amount of rare earth in each sample is significantly different,among which the semi-soil-soil-bauxite and oolitic bauxite are the two most prominent natural types,which are mainly related to the strength of leaching,redox environment and the relative oscillation frequency of water.As the basic constituent unit of rock ores--minerals,the surface relationship between minerals and mineral assemblage and rare earth enrichment has the characteristics of"independent minerals of lithologic total rare earth content is high,the oolite green mud rock rich rare earth,oolite lenticular bauxite less rare earth,high aluminum bauxite less rare earth".It is affected by the degree of close ion potential between the main and rare earth cations.In the aspect of rare earth enrichment mechanism,the mineral genesis analysis,the geochemical characteristics of rare earth elements and the method of map?Ni-Cr?Ti O₂-Zr??Ce-?Eu?Sr/Cu-?REE?Sr/Ba-?REE??Ce-?REE?were adopted,and the previous research results were combined.It is considered that the Al and REE final material source may be consistent in Xinmin bauxite deposit.However,the direct material source is slightly different.Al mainly comes from mudstone in Hanjiadian group.The REE source is mainly the mudstone of Hanjiadian group and a small amount of limestone of Huanglong group.In terms of occurrence characteristics,rare earth elements not only exist in the form of independent minerals and cerium-containing mixtures,but also occur on the surface,interlayer domain and crystal lattice of layered silicate minerals in the form of isomorphic or ion adsorption.Besides,heavy minerals such as rare-earth rich zircon and rutile are also important carriers.Although the ore-bearing rock series is formed in the environment with the change of temperature,humidity and dry climate,the transition of sea and land,and the continuous exchange of redox,the associated rare earth elements are easier to be enriched in the environment of dry and hot climate,Marine deposition and reduction.Therefore,under the background that the sources of REE materials in the study area are basically the same,the concentration degree of REE in the bottom of the ore-bearing rocks is comprehensively influenced by geological characteristics of the direct top and bottom,petrologic characteristics of the ore-bearing rocks?rock ore structure,rock ore type and mineral or mineral association?,the occurrence state of REE and the enrichment environment of REE,which jointly determines the distribution characteristics of"spoon-like"enrichment in the bottom.At the same time,the above related research results or understanding provide certain theoretical support and important reference for the spatial distribution characteristics and resource potential analysis of rare earth rich geological bodies in the research area.Therefore,the lower than upper mineralized section in the study area is not only complex in the spatial distribution characteristics of rare-earth rich geological bodies,but also has greater potential for associated rare earth resources than the upper mineralized section.