X射线衍射-电子探针研究冀北铁岭组古风化壳稀土元素赋存状态  

Occurrence State of Rare Earth Elements in the Paleo-Weathering Crust of the Tieling Formation,Northern Hebei Province by X-Ray Diffraction and Electron Probe Microanalysis

作　　者：陈海燕 张运强 毛香菊[2] 李瑞红 CHEN Haiyan;ZHANG Yunqiang;MAO Xiangju;LI Ruihong(Langfang Natural Resources Comprehensive Survey Center,China Geological Survey,Langfang 065000,China;Zhengzhou Institute of Multipurpose Utilization of Mineral Resources,Chinese Academy of Geological Sciences,Zhengzhou 450006,China)

机构地区：[1]中国地质调查局廊坊自然资源综合调查中心,河北廊坊065000 [2]中国地质科学院郑州矿产综合利用研究所,河南郑州450006

出　　处：《岩矿测试》2024年第6期836-846,共11页Rock and Mineral Analysis

基　　金：中国地质调查局地质调查项目(DD20242942,DD20230383)。

摘　　要：近年来发现的古风化壳型稀土矿具有稳定、易于开采等优点,由于对其元素赋存状态的研究程度较低,制约了矿床富集机理的研究。本文采用逐级化学提取、X射线粉晶衍射、重砂鉴定、电子探针等测试技术,对铁岭组古风化壳稀土元素的赋存状态进行了系统研究。逐级化学提取显示古风化壳中稀土元素主要以矿物相存在,约占总含量的99.38%。水溶相、离子相及胶态沉积相中的稀土元素分别占比0.01%、0.22%和0.39%;X射线衍射分析显示古风化壳样品中的伊利石、伊蒙混层等黏土矿物可能吸附了极少量稀土元素;电子探针测试结果显示古风化壳样品中的锐钛矿、白钛矿和重晶石中含有0.1%左右的Ce、Nd、Sm等轻稀土元素。初步认为:古风化壳中稀土元素主体以矿物相存在,一部分以类质同象赋存于锐钛矿、白钛矿和重晶石中,其余则可能以纳米级微细颗粒存在于锐钛矿表面以及大量的黏土矿物中。极少量的离子态稀土元素可能吸附于伊利石、伊蒙混层等黏土矿物表面;呈水溶相及胶态沉积相中的稀土元素含量极低。本文对古风化壳稀土元素赋存状态的研究有助于优化开发利用工艺,为稀土资源的选冶利用提供数据基础。In recent years,the discovered paleo-weathering crustal rare earth ores have the advantages of stability and easy mining.However,due to the low degree of research on their element occurrence state,the study of the enrichment mechanism of the deposits is restricted.In this paper,the occurrence state of rare earth elements in the paleo-weathering crust of the Tieling Formation was systematically studied by using the techniques of stepwise chemical extraction,X-ray diffraction,heavy minerals identification,and electron probe microanalysis.Stepwise chemical extraction shows that rare earth elements in the paleo-weathering crust mainly exist in mineral phases,accounting for about 99.38%of the total content.The rare earth elements in aqueous solution,ionic phase,and colloidal deposition phase account for 0.01%,0.22%and 0.39%,respectively;X-ray diffraction analysis shows that a small amount of rare earth elements in the ionic adsorption state in the paleo-weathering crust samples may exist on the surface of clay minerals such as illite;electron probe microanalysis results show that the anatase,leucoxene and barite in the paleo-weathering crust samples contain about 0.1%of light rare earth elements such as Ce,Nd and Sm.In summary,it is preliminarily concluded that the main rare earth elements in the paleo-weathering crust exist in mineral phases,some of them exist in anatase,leucoxene and barite as similar images,and the rest may exist on the surface of anatase and a large number of clay minerals in nano-scale fine particles.A very small amount of ionic rare earth elements may be adsorbed on the surface of clay minerals such as illite and illite-smectite mixed layer.The content of rare earth elements in the water-soluble phase and colloidal sedimentary phase is very low.The study on the occurrence state of rare earth elements in the ancient weathering crust helps to optimize development and utilization technology and provides a theory for the selection and smelting utilization of rare earth resources.

关 键 词：铁岭组 古风化壳 稀土元素 赋存状态 X射线粉晶衍射 电子探针 

分 类 号：P575.1[天文地球—矿物学] O614.33[天文地球—地质学]