超细粉末压片-X射线荧光光谱法测定磷矿石中12种组分

粉末压片法是一种理想的绿色环保制样方法,简单快速,但是粒度效应对测定结果的影响很大,限制了这种方法在很多领域的应用。为了解决粒度效应对粉末直接压片法的影响,实验利用超高速行星式超细碎样机,将磷矿石标准物质粉碎至微米级,采用粉末直接压片制样,利用波长色散X射线荧光光谱仪对磷矿石中12种组分(氟、五氧化二磷、二氧化硅、三氧化二铝、全三氧化二铁、氧化锰、二氧化钛、氧化锶、氧化钙、氧化锰、氧化钾、氧化钠)进行了测定。结果表明,将样品粉碎至微米级,能够有效地克服样品的粒度效应,获得了比较满意的结果;特别是将氟的测定范围提高到了10.68%,对轻组分氧化钾和氧化钠的测定结果也很好。采用多种磷矿石标准物质和人工配制标准物质制作校准曲线,各组分的均方根为0.001 1～0.53。校准曲线采用经验系数和康普顿散射线内标法校正组分间的吸收-增强效应,方法的检出限为3～282 μg/g。对两个磷矿石国家标准样品进行精密度考察,各组分测定结果的相对标准偏差(RSD,n=10)为0.17%～5.2%。对采用标准物质配制的混合标准样品进行准确度考察,测定值与参考值一致。

Determination of twelve components in phosphate ore by X-ray fluorescence spectrometry with ultra-fine powder tabletting

The pressed powder pellet method was an ideal, green and environment friendly sample preparation method. It was simple and rapid. However, the determination results were greatly affected by the granularity effect, limiting the application of this method in many fields. In order to solving the influence of granularity effect on direct tabletting of sample powder, the certified reference material of phosphate ore was grinded to micron size using the ultra-high-speed planetary superfine crusher. The sample was directly prepared with the powder. Then, the content of 12 components (fluorine, phosphorus pentoxide, silicon dioxide, aluminum oxide, total ferric oxide, manganese oxide, titanium dioxide, strontium oxide, calcium oxide, manganese oxide, potassium oxide and sodium oxide) in phosphate ore was determined by the wavelength dispersive X-ray fluorescence spectrometry. The results indicated that the crushing of sample into micron size could effectively overcome the granularity effect. The found results were satisfactory. Particularly, the determination range of fluorine was improved to 10.68%. The determination results of light components such as potassium oxide and sodium oxide were also good. The calibration curve was drawn by the certified reference material of phosphate ores and the artificially prepared standard materials. The root mean square (RMS) of components were between 0.001 1 and 0.53. The absorption-enhancing effect among components was corrected by the empirical coefficient and Compton scattering internal standard method. The detection limits of method were between 3 μg/g and 282 μg/g. The precision test was conducted using two national standard samples of phosphate ore. The relative standard deviations (RSD, n=10) were between 0.17% and 5.2%. The accuracy test was conducted by the mixed standard samples prepared using the certified reference materials. The found results were consistent with the reference values.