白云鄂博主矿和东矿不同类型矿石中萤石矿物学特征

Mineralogical Characteristics of Fluorite in Different Kinds of Ores of Main and East Orebodies of Bayan Obo Deposit

通过野外工作采集白云鄂博主矿和东矿不同类型矿石,制成探针片后在显微镜下进行岩矿鉴定。从不同类型矿石样品中挑出萤石单矿物颗粒,分为两部分,一部分进行X射线粉晶衍射测试和稀土含量分析,另一部分按颜色深度分为浅色和深色两种,进行X射线衍射测试。测试结果表明,萤石在矿床中分布十分广泛,与其它矿物生长关系复杂,同稀土、铁等矿物的形成关系密切;本次工作不同类型矿石中萤石的稀土含量从高到低为:白云石型铌稀土铁矿石>霓石型铌稀土铁矿石>钠闪石型铌稀土铁矿石>条带状铌稀土铁矿石,与对应萤石晶胞参数呈反相关关系;同种类型矿石中,随着萤石颜色的加深,其本身的晶胞参数也增加,反映了其颜色与结构的相关性。

Bayan Obo deposit is the largest rare earth deposit in the world,and there are lots of fluorite resources at the same time.Although some exploration and process mineralogy work have been carried out on the fluorite,more mineralogical researches of fluorite are needed.Different kinds of ores were collected from main and east Orebodies of Bayan Obo through the field work.After the samples were made into microprobe slice,the rock-mineral determination was carried out under the microscope.The single mineral particles of fluorite were separated from different kinds of ores and divided into two parts.One part was used for X-ray powder diffraction test and REE content analysis,the other part was divided into two types of samples:light colour and dark,which were tested by X-ray powder diffraction separately.It is found that:(1)Fluorite is widely distributed in the deposit and has a complex relationship with other minerals,which is closely related to the formation of rare earth minerals,iron minerals.(2)According to the REE content in fluorite,the order is dolomite type Nb-REE-Fe ore>aegirine type Nb-REE-Fe ore>riebeckite type Nb-REE-Fe ore>banded type Nb-REE-Fe ore,which is contrary to the lattice constants.(3)In the same type of ore,the lattice constants of fluorite increase with the deepening of the color of fluorite,which reflects the correlation between the color and structure.