滇东南建水铌稀土矿成矿元素含量与赋存状态

The Content and Occurrence State of Ore-forming Elements in the Jianshui Niobium-rare Earth Ore, Southeastern Yunnan

为查明滇东南建水铌稀土矿成矿元素的含量与赋存状态,矿区详查中对霞石正长岩风化壳的矿体进行了人工重砂分析、X-射线衍射分析、MLA分析、电子探针分析、化学多元素分析。将分析测试中得出的各种矿物的成矿元素质量分数,换算成不同矿物的成矿元素质量分数在矿石中所占比例,根据成矿元素在不同矿物中赋存的一般规律进行成矿元素赋存状态的研究。成矿元素以稀土元素、Nb2O5为主,有Ga2O3伴生。矿石中稀土元素全相质量分数为0.201%,主要赋存在稀土矿物和黏土类矿物中。离子相稀土元素赋存于高岭石类、云母类矿物中,质量分数为0.088%~0.101%,占全相比例的36.066%~41.394%。轻稀土元素与重稀土元素的全相、离子相比值分别为4.674、1.514~1.590,属轻稀土富集型。矿石中Nb2O5的质量分数为0.050%,主要赋存于含铌矿物和正长石中。赋存于黏土类和云母类中的Nb可能属离子相,Nb2O5质量分数分别为0.007%、0.003%,分别占矿石中总量的14.000%、6.000%。矿石中Ga2O3的质量分数为0.007%,主要赋存于正长石类、黏土类、云母类矿物中,黏土类、云母类矿物中Ga可能有一部分属离子相。与成矿母岩相比较,矿石中稀土元素、Nb2O5、Ga2O3均有不同程度富集。富集有2种途径:成矿母岩风化过程中易溶组分流失使有用矿物含量增高;有用组分呈离子吸附状态富集于黏土类、云母类矿物之中。

In order to find out the content and occurrence state of ore-forming elements in the Jianshui niobium-rare earth ore in southeastern Yunnan,artificial heavy sand analysis,X-ray diffraction analysis,MLA,electron probe analysis and multi-element chemical analysis were carried out in the ore body of the nepheline syenite weathering crust in the detailed investigation of the mining area.In this paper,the mass fractions of ore-forming elements of various minerals obtained from the analyses were first converted into the proportions of the ore-forming elements of different minerals in the ore,and according to the general regularity of ore-forming elements occurrence in different minerals,the occurrence states of ore-forming elements were further studied.The ore-forming elements are mainly rare earth elements and Nb2O5,accompanied by Ga2O3.The total mass fraction of rare earth elements in ore is 0.201%,which is mainly distributed in rare earth minerals and clay minerals.The ionic phase rare earth elements are present in kaolinite and mica minerals with a mass fraction of 0.088%to 0.101%,accounting for 36.066%to 41.394%of the all phase rare earth in the ore.The all phase rare earth ratio of the light rare earth element and the heavy rare earth element is 4.674,and ionic phase rare earth ratio of the light rare earth element and the heavy rare earth element is 1.514 to 1.590.The ore samples are light rare earth enriched type.The mass fraction of Nb2O5 in the ore is 0.050%,mainly in the niobium-containing minerals and feldspar.Niobium in the clay and mica may belong to the ionic phase.The mass fraction of Nb2O5 is 0.007%and 0.003%for clay and mica,respectively,accounting for 14.000%and 6.000%of Nb2O5 in the ore.The mass fraction of Ga2O3 in the ore is 0.007%,which is mainly found in feldspar,clay and mica minerals.Gallium in the clay and mica minerals may be part of the ionic phase.Compared with the ore-forming parent rock,rare earth elements,Nb2O5 and Ga2O3 in the ore have different degrees of enrichment.There are two ways to make them enriched:firstly,the loss of soluble components in the weathering process of the parent rock resulted in increasing the content of useful minerals,and secondly,the useful components are enriched in clay and mica minerals in the state of ion adsorption.