X射线荧光光谱法分析矿石样品时工作曲线的精确调整

Precise and Accurate Calibration of Working Curves in XRFS Analysis of Ore Samples

应用X射线荧光光谱法分析了矿石样品。将粉碎至粒径为0.088mm的矿样用模压法在32MPa压力条件下加压40s,压制成直径为40mm,厚度为3mm的片样。试验从生产线上选取15个各组分元素含量呈梯度分布的样品以抵消其基体效应,并选用一组已知样品制作工作曲线。以MXF-2400型X射线荧光光谱仪所附带的PC-MXF-E软件中的校正公式,通过化学计量学处理,包括拟合评估、遗传算法及收敛条件的满足等,达到了X射线荧光光谱法分析矿石样品时工作曲线的精确调整。应用此方法分析了3组地质样品,所测定的铜、铅、锌3种元素的含量与化学法所测得的结果完全一致,又用同一样片对其中的5项组分进行6次测定,所得测定值的相对标准偏差均小于1%。

Ore samples were analyzed by XRFS.Disc samples with 40 mm in diameter and 3 mm in thickness were prepared by pressing of sample powder（with size of 0.088 mm） with moulding press under 32 MPa for 40 s.Samples with components in mass fraction gradients were selected from production lines to overcome the matrix effects and a set of known samples were used for preparing the working curves.Based on the correction formula given in the PC-MXF-E soft-ware of MXF-2400 XRF spectrometer,chemometric manipulations of fitting evaluation,genetic algorithm and fulfilling conditions of convergence,were carried out to attain precise and accurate calibration of the working curves in XRFS analysis of ores.As shown in the analysis of three sets of geological samples,consistence between results of contents of Cu,Pb and Zn obtained by this method and by the chemical method were acquired and values of RSD′s（n=6） obtained for 5 elements were all less than 1%.