Determination of major and minor components in bauxite by X-ray fluorescence spectrometry with fusion sample preparation
The accurate determination of major and minor components in bauxite is of great significance for the assigning of bauxite grade as well as the selection of smelting and production parameters.The content range of more than ten major and minor components in bauxite is usually wide,and two or more analysis methods are commonly employed for the determination.In this study,the certified reference material of bauxite and three certified reference materials of clay having similar composition with bauxite were used to prepare the calibration curve.The matrix effect was corrected by the variation theoretical α coefficient.Spectra plus software was used for the correction of loss on ignition(LOI).The method for the determina-tion of major and minor components in bauxite(Al2O3,CaO,MgO,P2O5,Fe2O3,TiO2,MnO,SiO2,K2O and Na2O)by X-ray fluorescence spectrometry(XRF)with fusion sample preparation was established.The re-sults showed that the uniform and transparent beads could be prepared under the following experimental conditions:the mixed flux of lithium tetraborate-lithium metaborate(mass ratio of 67∶33)was used as the flux;the dilution ratio was controlled at 1∶23;1.0 g of lithium nitrate was added into the mixture of sam-ple and flux;the sample was peroxidized at 600 ℃ for 5 min and then fused at 1 075 ℃ for 10 min;total 50 mg of ammonium iodide was added in three batches as the release agent.The influence of two correction methods of loss on ignition(i.e.,Spectra plus software and sample calcination)on the determination re-sults of major and minor components in bauxite was investigated.The results showed that the results of two methods were basically consistent.One bauxite sample was determined in parallel for 11 times within one day by one analyst under same environment.The relative standard deviations(RSD,n=11)of determi-nation results were between 0.20％and 4.1％.It was also determined in parallel for 11 times within 15 days by different analysts under same environment.The RSDs of determination results were between 0.25％and 4.7％.The contents of major and minor components in two bauxite samples were determined according to the experimental method,and the results were basically consistent with those obtained by ti-tration or inductively coupled plasma atomic emission spectrometry(ICP-AES).
X-ray fluorescence spectrometry(XRF)fusion sample preparationbauxiteSpectra plus soft-wareloss on ignition correctionvariation theoretical α coefficient
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