Determination Of 16 Major And Minor Elements In Silicate Rock By Wavelength X-ray Fluorescence Spectrometry With Sample Fusion

The total percentage analysis of silicate rock is not only an effective measure for the quality check and analysis of analytical workers,but also provides geological researchers with basic and regular information on geology.The accurate analysis of ten major components in silicate rock,SiO₂,Al₂O₃,TFe2O3,Ca O,Mg O,K₂O,TiO₂,Mn O,Na2 O and P2O5 is an area of great concern to the analytical workers.In recent years,XRF method has replaced the traditional chemical analysis methods in daily analysis because of its advantages such as simple melting,multi element simultaneous measurement and accurate measurement results.Accuracy and precision of the analytical results for major and minor in silicate rock by the X-ray fluorescence spectrometry with fused sample preparation can be seriously affected by the type of silicate rock samples being analysed and the complex components it contains.The specific research is as follows:（1）First of all,the standard curve of XRF method testing samples must be established before using the standard curve analysis.sample results depend heavily on the accuracy of the application of standard material standard,so to establish a standard curve must have the appropriate standard material as a support.Wavelength dispersive X-ray fluorescence spectrometer,meanwhile,highly automated,programming,testing process,the instrument test background and pulse height analyzer（PHD）set a greater influence on the accuracy of analysis results.Therefore,Background and PHD settings are difficult and important in measurement conditions.In the study,the paper choose 17 silicate rock the national certified reference materials to ensure the best possible matrix reference materials to establish the standard curve of the sample matrix is consistent with the actual samples.A reasonable background setting condition was selected for the analysis and of 16 major and minor components in the sample of silicate rocks.（2）The pape selects the mixture of lithium tetraborate and lithium metaborate has been used as flux.In order to successfully prepared the glass bead with high precision,melting on the influence of melt quality and flux,flux and sample dilution ratio,oxidant,complex sample experiment started.The silicate samples were tested by melting XRF method in the study.Among them,the preparation of molten is critical,and the quality of the preparation determines the accuracy and precision of the analysis results.The fused pellet has been made as follows: the mixture of lithium tetraborate and lithium metaborate（Li2B4O7:Li BO2:Li F=12:22）has been used as flux,lithium nitrate has been used as oxidant,Lithium bromide as release agent,and dilution ratio has 10:1 after roasted in1100℃,melting into the glass is transparent and smooth,uniform.The calibration curve was corrected by the method of D·J model theoretical alpha coefficient to the matrix effect and spectral overlap between elements.Determination of 16 components including SiO₂,Al₂O₃,TFe2O3,Ca O,Mg O,K₂O,TiO₂,Mn O,Na2 O,P2O5,SO3,Ba O,V2O5,Cr₂O₃,Sr and Zr in silicate rock by X-ray fluorescence spectrometry with fused pellet was established.（3）Through a series of test conditions selection and correction,The validity of the method was substantiated by analyzing the national primary silicate rock reference materials（GBW07121、GBW07123）,the relative standard deviations（RSD）were from 0.06% to 3.19%.Analysis results of the national primary silicate rock reference materials（GBW07102、GBW07122、GBW07835）,Which do not participate in regression were basically in good agreement with certified values.We selected 21 silicate rock samples to Central Lab Institute of Geophysical & Geochemical Exploration,CAGS（National Laboratory Accreditation）,The two units of analysis results for the ten major components are in conformity with the 《Standard for quality control of laboratory test of Geology and mineral》（DZ/T0130—2006）.the determination of ignition loss and Fe O content by chemical method,then add% and all the results achieved the 《standard》 of first levels: 99.3% 100.7%.Due to incomplete oxidation of sulfur at low valence state and volatilization of SO42-from S in high temperature melting process,SO3 content test has not obtained satisfactory results,and will be the focus of efforts in future work.