粉末压片-X射线荧光光谱法测定高炉除尘灰中钾铅锌砷

以粉末压片制样,采用X射线荧光光谱法(XRF)测试高炉除尘灰中氧化钾、铅、锌和砷含量。对样品除碳方式、样品粒度、分析谱线、光学背景等条件进行了优化。试验发现:热电灰在500 ℃灼烧2 h、瓦斯灰在600 ℃灼烧3 h的除碳方式,可消除试样中高含量碳的干扰;样品粒度小于125 μm时测定结果的精密度较好;以Pb-Lβ、As-Kβ,、K-Kα、Zn-Kα作为分析谱线可避免光谱干扰;对钾和锌元素,采用一点法扣背景,而对于铅和砷元素,采用两点法扣除背景可克服光学背景干扰;以铁矿石标准样品和经原子吸收光谱法(AAS)定值并经灰分校正的高炉灰样品作为校准样品绘制校准曲线,4组分的线性相关系数(R²)在0.998 5～0.999 8之间。对一个高炉热电灰样品进行精密度考察,结果的相对标准偏差(RSD,n=7)均不超过1%。对一组高炉除尘灰样品进行对比分析,4组分的测试结果同AAS相符。

Determination of potassium,lead, zinc and arsenic in blast furnace dust by X-ray fluorescence spectrometry with pressed powder pellet

The content of potassium oxide, lead, zinc and arsenic was determined by X-ray fluorescence spectrometry (XRF) with pressed powder pellet. The conditions including decarbonizing manner, sample granularity, analytical lines and optical background were optimized. It was found that: the interference from high content carbon in the sample could be removed through burning thermoelectric ash at 500 ℃ for 2 h and gas ash at 600 ℃ for 3 h; the results precision was fine when the sample granularity was smaller than 125 μm; and spectral interference could be avoided with Pb-Lβ, As-Kβ, K-Kα, Zn-Kα as analytical lines; background interference could be overcome with one point background deduction for K and Zn and two-point background deduction for Pb and As; when the iron ore certified reference materials and the blast furnace dust sample which were certified by atomic absorption spectrometry and calibrated by ash were used as calibration sample to establish calibration curve, the linear correlation coefficient (R²) of four components were 0.998 5-0.999 8. Precision test was conducted on a blast furnace thermoelectric ash. The relative standard deviation (RSD, n=7) was not more than 1%. A group of blast furnace dust samples were analyzed and compared. The results of the four components were consistent with those obtained by atomic absorption spectrometry.