矿物药麦饭石偏光显微特征及其X射线衍射指纹图谱分析

Analysis of Polarizing Microscopic Characteristics and X-ray Diffraction Fingerprint of Mineral Medicine Maifanitum

目的:分析不同产地麦饭石样品的偏光显微特征、物相组成及其相对含量,并建立麦饭石粉晶X射线衍射(XRD)Fourier特征指纹图谱。方法:选择26批麦饭石样品,利用偏光显微镜观察单偏光、正交偏光下样品粉末及磨片的显微特征,通过粉晶XRD技术分析主要物相组成及其相对含量,并建立麦饭石XRD Fourier特征指纹图谱。XRD入射光源为Cu靶Kβ辐射,光管电压和光管电流分别为40 kV和40 mA,发散狭缝1°,散射狭缝1°,接收狭缝0.2 mm,扫描速度5°·min^(-1),持续扫描,扫描范围5~90°(2θ),步长0.02°。结果:获得了麦饭石粉末、磨片的偏光显微特征图,其主要物相组成为斜长石、石英和钾长石,少数样品尚含有伊利石、黄铁矿、铁白云石、方解石、铁闪石及绿泥石等。长石类物相相对总质量分数、石英相对质量分数分别在61.9%~82.4%、12.6%~33.6%。建立了以13个共有峰为特征指纹信息的麦饭石XRD Fourier指纹图谱分析方法,均值相关系数法计算的相似度0.9209~0.9977,均值夹角余弦法计算的相似度0.9405~0.9984,中位数相关系数法计算的相似度0.9211~0.9975,中位数夹角余弦法计算的相似度0.9475~0.9982。结论:麦饭石的偏光显微鉴别特征主要为斜长石、石英及钾长石,且粉晶XRD Fourier指纹图谱分析技术可用于麦饭石的鉴别。

Objective:To analyze the polarized light microscopic characteristics,the composition of physical phases and their relative contents of Maifanitum from different origins,and to establish the Fourier characteristic fingerprint of Maifanitum powder crystals by X-ray diffraction(XRD).Method:A total of 26 batches of Maifanitum samples were selected,and the microscopic characteristics of the sample powders and grinding flakes were observed by polarized light microscopy under single polarized light and orthogonal polarized light,and the main phase compositions and their relative contents were analyzed by powder crystal XRD technique,and the XRD Fourier characteristic fingerprint of Maifanitum was established.The incident light source of XRD was Cu target Kβradiation,the light tube voltage and light tube current were 40 kV and 40 mA,respectively,the divergence slit was 1°,the scattering slit was 1°,the receiving slit was 0.2 mm,the scanning speed was 5°·min-1 with continuous scanning and scanning range of 5-90°(2θ),and the step length was 0.02°.Result:The polarized light micrographs of powders and grinding flakes of Maifanitum were obtained,and the main phases were plagioclase,potassium feldspar and quartz,and a few samples also contained illite,pyrite,iron dolomite,calcite,iron amphibole and chlorite,etc.The relative total content of feldspar phases was 61.9%-82.4%,and the relative content of quartz was 12.6%-33.6%.The XRD Fourier fingerprint analysis method of Maifanitum with 13 common peaks as the characteristic fingerprint information was established,and the similarity calculated by the mean correlation coefficient method was 0.9209-0.9977,the similarity calculated by the mean angle cosine method was 0.9405-0.9984,the similarity calculated by the median correlation coefficient method was 0.9211-0.9975,and the similarity calculated by the median angle cosine method was 0.9475-0.9982.Conclusion:The polarized light microscopic identification characteristics of Maifanitum are mainly plagioclase,quartz and potassium feldspar,and the technique of powder crystal XRD Fourier fingerprint analysis can be used for the identification of Maifanitum.