全自动制样-X射线荧光光谱法测定硅铁中硅

采用全自动制样,建立了X射线荧光光谱法(XRF)快速测定硅铁中硅的方法。通过对比X-ray专用助磨剂、进口助磨剂、微晶纤维素、硬脂酸等几种助磨剂在制作硅铁压片时的使用效果,确定使用X-ray专用助磨剂作为硅铁压片添加剂,样品与助磨剂的添加比例为9:1(质量比);全自动制样机制备硅铁压片时,样品初始粒度要求过160目筛网(孔径96 μm)、研磨时间为130 s、压力为35 t、保压时间为20 s。用上述方法可以得到结构均匀致密、外表平整光滑的硅铁压片。采用不同时期的多个生产样合并为一个管理样,与购买的硅铁标样配制校准曲线标样,校准曲线硅含量范围能够满足测定要求,并有效消除矿物效应对测定的影响。采用实验方法测定硅铁中硅,分析结果同SN/T 1014.1—2001的氟硅酸钾滴定法相吻合,相对标准偏差(RSD,n=11)小于0.2%。

Determination of silicon in ferrosilicon by X-ray fluorescence spectrometry after fully-automatic sample preparation

The rapid determination method of silicon in ferrosilicon by X-ray fluorescence spectrometry (XRF) after fully-automatic sample preparation was established. The effect of several grinding aids (including specific grinding aid for XRF analysis, imported grinding aid, microcrystalline cellulose and stearic acid) on pressed ferrosilicon sample was compared. The specific grinding aid for XRF analysis was selected as additive for sample preparation of ferrosilicon. The addition ratio of sample and grinding aid was 9:1 (mass ratio). During the preparation of ferrosilicon sample by fully-automatic machine, the initial particle size of sample should pass through 160-mesh screen (particle size of 96 μm). The grinding time was 130 s, the pressure was 35 t and the pressure keeping time was 20 s. The ferrosilicon sample with uniform and dense structure and smooth surface could be obtained. Several production samples from different stages were combined as one control sample, which was used to prepare calibration curve with purchased ferrosilicon standard sample. The content range of silicon in calibration curve could meet determination requirements. The influence of mineral effect on determination could be effectively eliminated. The proposed method was applied to the determination of silicon in ferrosilicon. The found results were consistent with those obtained by SN/T 1014.1—2001 potassium fluosilicate titration method. The relative standard deviation (RSD, n=11) was less than 0.2%.