连续小波变换-X射线荧光光谱定量分析铁矿石中二价铁

Quantitative analysis of ferrous iron in iron ores by X-ray fluorescence spectrometry with continuous wavelet transform

二价铁是钢铁冶炼的重要指标,需要进行严格控制。常规二价铁检测采用化学湿法,方法相对繁琐、耗时长。随着分析仪器的发展和新的数据处理技术的出现,利用X射线荧光光谱法(XRF)结合连续小波变换图谱处理,能提升二价铁检测的效率。方法利用FeKβ图谱连续小波变换后系数的最大值与FeKβ净积分强度的比值来研究铁矿石中的铁价态。研究表明该比值只与Fe2+和Fe3+的相对含量有关,再利用铁矿石样品通过线性回归建立了该比值与FeO/T.Fe(二价铁与全铁含量之比)之间的关系,同时分析了小波函数选择、特征点选取、测量谱线等对检测结果精密度的影响。对两个铁矿石样品进行精密度考察,FeO测定结果的相对标准偏差(RSD,n=7)均小于3%;对铁矿石实际样品中FeO的测定结果与国标方法相一致;两种方法具有较好的可比性,实验方法可以作为新标准制定建立的技术基础。

The content of ferrous iron is an important index in iron and steel smelting, and should be strictly controlled. In the past, the ferrous iron is usually determined by chemical method which has some disadvantages such as tedious operation and time consumption. With the development of analytical instrument and the appearance of new data process techniques, the detection efficiency of ferrous iron can be improved by X-ray fluorescence spectrometry (XRF) combined with spectrum processing with continuous wavelet transform.The valence of iron in iron ore was studied using the ratio between coefficient maximum of FeKβ spectrum after continuous wavelet transform and the net integral strength of FeKβ spectrum. The results showed that this ratio was only related to the relative content of Fe 2+ and Fe 3+. Then the relationship between this ratio and FeO/T.Fe (the content ratio between ferrous iron and total ion) was established by linear regression using iron ore samples. The effect of wavelet function selection, characteristic point selection and testing spectral line on the precision of determination results was discussed. Two iron ore samples were used for precision test. The relative standard deviations (RSD, n =7) of determination results of FeO were both less than 3%. The determination results of FeO in actual iron ore sample were consistent with those obtained by national standard method. Two methods showed good comparability. The proposed method could provide technological base for the establishment of new standards.