X射线荧光光谱法分析铁矿石中19种组分

Determination of nineteen components in iron ore by X-ray fluorescence spectrometry

选用铁矿石试样与混合熔剂（四硼酸锂-偏硼酸锂-溴化锂）、稀释比为l：12、1000℃熔融25min制备熔片，应用X射线荧光光谱法（XRF）测试铁矿石中全铁、二氧化硅、三氧化二铝、氧化钙、氧化镁、氧化锰、二氧化钛、磷、硫、氧化钾、氧化钠、五氧化二钒、铬、镍、铜、锌、砷、铅、氧化钡等19种组分。通过标准物质、光谱纯物质、人工合成样品及化学定值样品制作校准曲线并进行分段回归。添加氧化钴作内标校正元素铁，应用康普顿散射线校正铜、锌、砷、铅，采用经验系数法校正其他14种组分，可有效克服测定各类铁矿石中各组分时基体效应的影响。对铁矿石样品进行精密度试验考察，各组分测定结果的相对标准偏差（RSD，n=11）在0．13％～7．7％之间；对标准样品及未知样品进行准确度考察，测定值与认定值或湿法值一致。

The iron ore sample is prepared by fusion method under the following conditions:the mixed flux(lithium tetraborate-lithium metaborate-lithium bromide),the dilution ratio of 1∶12,and fusion at 1 000℃for 25 min.The content of 19 components in iron ore were determined by X-ray fluorescence spectrometry(XRF),including total iron,silicon dioxide,aluminum oxide,calcium oxide,magnesium oxide,manganese oxide,titanium dioxide,phosphorus,sulfur,potassium oxide,sodium oxide,vanadium pentoxide,chromium,nickel,copper,zinc,arsenic,lead and barium oxide.The calibration curves were prepared and piecewise regressed using the certified reference materials,spectral purity materials,artificially synthesized samples and samples which were certified by chemical method.The cobalt oxide was added as the internal standard to correct the determination of total iron.The elements of copper,zinc,arsenic and lead were corrected by the Compton scattering line.Other 14 components were corrected by the empirical coefficient method.The matrix effect could be effectively eliminated.The precision test of iron ore sample was conducted.The relative standard deviations(RSD,n=11)were between 0.13% and7.7%.The accuracy tests of standard sample and unknown sample were also conducted.The found results were consistent with the certified values or those obtained by the wet method.