Application Of Modern Microbeam Analysis Techniques In Study Of Micro Minerals

We often have difficulties in reaserch on mineralgy and ore smelting of many important deposits considering the complicated mineral structure and small particle size of ore minerals.In this paper,the comprehensive information of domestic and foreign advanced mineral microbeam analysis method were gathered,and minerals in10um?50um of gold deposits with telluride minerals like Sandaowanzi,Beidagou,Daxintun in China's Heilongjiang province and Dong Ping in He Bei province were reaserched by try using these microbeam analysis method,aiming to find a series of analysis methods fit for fine-grained minerals in chemical component,physical phase and crystal structure.In the aspect of chemical composition analysis,A set of complementary major element,microelement and trace element analysis system which is in-situ and nondestructive for the mineral thin sections is formed by scanning electron microscope(SEM),electron probe microanalysis(EPMA),ion microprobe mass spectrometer(SIMS),laser ablation inductively coupled plasma mass spectrometry(LA ICP MS),scanning nuclear microprobe(SNM)and synchrotron radiation X-ray fluorescence microprobe(SRXRF micro-probe).SEM can analyze main elements whose content is more than 1%in the sample with nanoscale spatial resolution,EPMA can analyze main elements which content is more than 0.01%with spatial resolution after SEM,the sensitivity of SIMS,LA ICP MS,SNM and SRXRF micro-probe have been reached 10^-6?10^-10 and can analyze trace elements which content was less than ppm but with a poor spatial resolution.In the aspect of analysis of phase identification,microbeam X-ray diffraction(XRD)is the most effective and direct phase analysis method.General XRD can identify mineral phase which particle size is greater than 50 um,while when the mineral particle size is smaller than the X-Ray beam spot and multiple mineral phase are analysised together,the experimental result is not so accurate,but we can increase the experiment time to collect more diffraction signal;Synchrotron radiation microbeam XRD can identify mineral phase which particle size is greater than 1 um and the result is accurate,while the experimental facilities is the state-level large-scale experiment device and the experiment application need to pass strict examination and approval.In the aspect of crystallographic structural analysis,crystallographic structural can be analysised by X-ray diffraction structure refinement and electron diffraction technique of Transmission Electron Microscopy(TEM).Software named JADE can parse mineral crystal cell parameters and GSAS can work out mineral atom coordinates on the basis of X-ray diffraction and build the model of the crystal structure in the Dimond;High Resolution Transmission Electron Microscopy(HRTEM)can not only parse mineral crystal cell parameters but also mineral high resolution atom image on the base of nanoscale sample preparation technique named Focused ion beam(FIB).Analysis of phase identification was conducted on the probable new mineral"Au₂Te"by Microbeam X-ray diffraction(XRD),EPMA and SEM,results show that"Au₂Te"is not a independent mineral but a mineral intergrowth texture consists of native gold and calaverite which looks like about 50 nm filaments respectively.