X射线荧光光谱法测定工业硅中11种微量元素

通过定性半定量分析软件IQ⁺测定淀粉、甲基纤维素、硼酸、硬脂酸等常用粘结剂中微量元素含量,选择硼酸和硬脂酸做混合粘结剂,研磨压片法制备样品,用X射线荧光光谱仪(XRF)测定工业硅中铁、铝、钙、锰、镍、钛、铜、磷、镁、铬、钒的元素含量。块状工业硅样品用铁坩埚处理,使用筛网选取1～3 mm的颗粒作为待研磨样品。通过实验确定了最佳的样品和粘结剂比例为15 g工业硅试样加入3.0 g硼酸和0.20 g硬脂酸;条件试验表明,研磨时间达到120 s以后粒度效应明显减弱,在此条件下研磨压制成片后分析面坚固平滑。用工业硅系列标准样品制作校准曲线,并采用经验系数法进行校正;共存元素之间进行谱线重叠校正,由分析软件计算得到校准曲线的均方根偏差(RMS)小于方法要求的RMS值。样品精密度试验表明,工业硅样品中铁、铝、钙、锰、磷、镍、钒、钛、镁测定结果的相对标准偏差(RSD,n=11)一般在5%左右,铬元素的RSD最高,但也在9%以下。实验方法用于工业硅标准样品的分析,测定值与认定值一致;未知样品的检测结果也与电感耦合等离子体原子发射光谱法(ICP-AES)分析结果没有显著性差异。

Determination of eleven micro elements in industrial silicon by X-ray fluorescence spectrometry

The content of micro elements in common binders (including amylum, methylcellulose, boric acid and stearic acid) was determined by qualitative and semi-quantitative analysis software IQ⁺. The sample was prepared by grinding and powder pressed method using boric acid and stearic acid as mixed binder. The content of iron, aluminum, calcium, manganese, nickel, titanium, copper, phosphorus, magnesium, chromium and vanadium in industrial silicon was determined by X-ray fluorescence spectrometry (XRF). The block-type industrial silicon samples were treated using iron crucible. The particles with size of 1-3 mm passing through the screen were used as samples for grinding. The optimal ratio of sample and binder was obtained by experiments, i.e., 15 g of industrial silicon sample was mixed with 3.0 g of boric acid and 0.20 g of stearic acid. The conditional tests showed that the granularity effect was obviously reduced when the grinding time was more than 120 s. The surface for analysis after sample preparation was firm and smooth. The calibration curve was prepared using the series certified reference materials of industrial silicon and then corrected by empirical coefficient method. The spectral overlapping between coexisting elements was corrected. The root mean square deviation (RMS) of calibration curve obtained by analytical software was less than the RMS value required. The precision test results indicated that the relative standard deviations (RSD, n=11) of iron, aluminum, calcium, manganese, phosphorus, nickel, vanadium, titanium and magnesium in industrial silicon sample were about 5%. The RSD of chromium was highest, which was also less than 9%. The proposed method was applied to the analysis of industrial silicon standard samples, and the found results were consistent with the certified values. The determination results of unknown samples had no significant difference with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES).