高分辨扫描电镜和X射线能谱Mapping技术研究碲矿物的成分和形态特征

Application of High-resolution Scanning Electron Microscope and X-ray Energy Dispersive Spectroscope Mapping Technique to Study the Composition and Morphology of Tellurium Minerals

X射线能谱元素像分析技术(EDS-Mapping)可直接观察岩石光片中目标元素的分布特征。本文采用高分辨扫描电镜及配置的X射线能谱仪综合分析技术,对山东归来庄金矿中碲元素和其他元素的分布特征和组合规律进行研究,定性确定含碲矿物、形态特征及其与其他矿物间的空间关系。结果表明,研究区金矿中含碲矿物有棱角状碲金银矿、碲化铅等,以浸染状形貌他形镶嵌于主矿物他形石英和片状云母之间,颗粒大小从几微米到几百微米极不均匀。对典型含碲矿物的微区成分进一步精确测定,得到碲金银矿和碲化铅的化学式为Ag_(0.85)Au_(2.55)Te_6和Pb_(0.52)Te_(0.48),其中碲金银矿成分明显异常。本文研究为稀散分布微细矿物的成分、形态分布及与围岩关系建立了一套先进实用的表征方法,可为含碲金矿的综合利用提供技术支持。

The X-ray Energy Dispersive Spectrometry EDS-Mapping technique can be used to directly observe distribution characteristic of elements in rock sections. The distribution characteristics and elemental assemblage of tellurium （Te） and some other elements （Au and Ag） from the Guilaizhuang gold field in Shandong Province of China were investigated by high resolution Scanning Electron Microscope （SEM） and X-ray Energy Dispersive Spectroscope （EDS） Mapping techniques and are presented in this paper. The morphological characteristics of possible Te minerals, as well as the spatial relationship between Te minerals and other minerals, were also qualitatively determined. The results show that the Te-bearing minerals in the Zhuojiazhuang gold deposit include angular sylvanite and altair, which were disseminated in the space between anhedral quartz and sheet muscovite. The Te-bearing minerals have particle sizes ranging from a few to hundreds of micrometers. Microanalysis of the Te-bearing minerals indicates that the chemical formulae of sylvanite and altaite are Ag0.85 Au2.55 Te6 and Pb0.52Te0.48, respectively. Sylvanite has an abnormal chemical composition. Through the study, an advanced and practical technique for analyzing the composition and the morphological characteristics of Te minerals and their relationship with wallrock was developed. This study also provides technique support for comprehensive utilization of Te-bearing gold minerals.