Study On Migration Mechanism And Efficient Utilization Of H8 Carbonate Rare Earth Elements In Bayan Obo

Based on the theoretical knowledge of petrology,mineralogy,Raman spectroscopy,electromagnetism and Mineral processing,and previous studies,in this thesis selects five major rare earth minerals in the Bayan Obo deposit.The distribution characteristics,chemical composition,mineral structure,and efficient utilization of rare earth resources were studied.Focus on the combination of Raman spectroscopy and traditional technology to study the Raman spectroscopy characteristics of rare earth and surrounding minerals from an in-situ perspective.Discover and discuss the genesis,migration,and enrichment mechanism of the Banyan Obo deposit.1.According to the automatic mineralogical analysis of TIMA（Tescan Integrated Mineral Analyzer）,bastnaesite in massive iron rare earth ore is filled in the iron mineral aggregate in the form of disseminated,scattered,or banded.The immiscibility between iron minerals and barite solution is obvious,which indicates that the migration and enrichment of rare earth elements are greatly influenced by barite solution.The banded rare earth ores can be divided into barite type and fluorite type,and barite type occurs in iron mineral aggregates in striped veinlets.A small amount of barite melt is filled,which indicates that the metallogenic system has entered the stage of barite mineralization decline,which is consistent with the previous research conclusions.However,fluorite-type rare earth mineralization is related to apatite solution,and rare earth minerals at least undergo strong metasomatism of fluorine-rich and phosphorus-rich solution.There are two kinds of rare earth ores of aegirine type:disseminated and banded.Comprehensive analysis shows that some rare earths in minerals exist in apatite inclusions,which shows the‘dissolution-reprecipitation’effect of apatite solution.Under the strong F-Na metasomatism,minerals rich in rare earth and niobium are formed.Rare earths in dolomite-type rare earth ores are distributed in dispersed or irregular veins,disseminated,patchy and banded aggregates,and iron mineralization and rare earth mineralization are obvious.2.The earth analysis of trace elements in the Bayan Obo mine shows that the standardized distribution of dolomite-type rare earths shows a stable linear law,which is quite different from other types.From the analysis of the overall distribution law,they all show the characteristics of high enrichment of light rare earth and relative loss of heavy rare earth,indicating that the rare earth elements in the deposit come from the same source.Taking dolomite-type rare earth ore as the standard base mineral,the migration law of main micro,quantity,and rare earth elements during hydrothermal alteration and metasomatism of the deposit is studied.The study shows that during hydrothermal alteration of the deposit,the hydrothermal fluid containing Na,K,Mg,Ca,and Fe elements altered the contact rocks.And interact with a hydrothermal solution containing F,P,and S elements to bring in or bring out rare earth elements in different degrees.The analysis shows that rare earth mineralization is driven by multi-stage dissolution,reactivation,and reprecipitation of molten fluid,and the rare earth elements constantly migrate,eventually forming different types of rare earth mineralization zones.3.By using Raman spectrum analysis technology,the variation of polarization plane orientation of mineral crystals caused by the Raman laser is analyzed.Summarize the growth orientation relationship of mineral crystals and judge the multi-stage mineralization of rare earth minerals.By studying the Raman spectra of apatite minerals,it is found that apatite in the deposit is hydroxyapatite minerals.It shows that there is water or hydroxyl when the apatite solution is mineralized during mineralization.It has a great influence on adjacent minerals,but the distance does not.Combined with previous research results,it is found that the Raman band of apatite at1523cm^-1（ν₁）is the characteristic peak of cyanobacteria.From the point of view of Raman spectroscopy,it is shown that the rich dolomite has the biological mineralization stage of rare earth minerals,and the rare earth-rich mineralization has the possibility of sedimentary genesis.Using Raman 3D-Mapping imaging technology to study ore-forming solutions,it is found that barite minerals have three different crystal forms.It shows that there are at least three mineralization periods in the stage of sulfate solution affecting rare earth mineralization.From the particle morphology of rare earth minerals,it can be seen that rare earth mineralization takes a long time,and sulfate-rich fluid plays a key role in the activation,migration,and mineralization of rare earth elements.4.The occurrence characteristics of the Bayan Obo mine and the co-occurrence degree of rare earth elements are analyzed,and the separability of minerals and the occurrence law of rare earth and gangue are studied.A separation and enrichment theory was proposed by comprehensively applying the basic methods of mineral processing.By using XRF sorting technology,high-grade rare earth minerals are obtained from the concentrate and high-grade iron minerals are obtained from the tailings.The experimental results show that the rare earth minerals after XRF enrichment and magnetic separation can obtain a double‘50%’beneficiation index superior to that of Baotou Steel,and rare earth concentrates with a rare earth grade of 69.62%and a recovery rate of 70.57%can be obtained.Meanwhile,a new beneficiation process is established to effectively recover and protect the existing rare earth resources.To sum up,the mechanism of migration and enrichment of rare earth elements and the ore-forming solution is deeply analyzed by combining TIMA with Raman spectroscopy,and the evidence of multi-stage mineralization of minerals is intuitively judged by using the particularity of Raman peak of minerals.Combined with the observation results of mineralogy and spectroscopy,it is proved for the first time that Bayan Obo apatite exists as hydroxyapatite,and recently it is possible that there is sedimentary origin in the mineralization of the Bayan Obo deposit.For the comprehensive utilization of rare earth mineral resources,XRF separation technology is put forward,which has important practical significance and application prospects for the efficient utilization of rare earth.