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    粉末压片-波长色散型X射线荧光光谱法测定废弃印刷线路板中10种金属元素的含量

    Determination of 10 Metal Elements in Waste Printed Circuit Boards by Wavelength Dispersive X-Ray Fluorescence Spectrometry with Powder Tablet

    • 摘要: 测定废弃印刷线路板(WPCBs)中金属元素含量的方法均需对样品进行消解,操作复杂耗时;X射线荧光光谱法无需样品消解,但由于缺少相似基体的标准样品而定量不准确。基于此,以与WPCBs在元素组成上较为相似的地质类标准物质作为本底物,按不同比例添加环氧树脂及铜粉制备一系列校准样品并绘制校准曲线,提出了题示研究。取WPCBs研磨,过200目(0.074 mm)筛,于105 ℃烘干,取上述样品5 g置于不锈钢模具中,加入硼酸镶边,用压片机(压力200 kPa,保压时间20 s)制成直径40 mm圆片,采用波长色散型X射线荧光光谱法(WD-XRF)测定其中银、钡、铬、铜、铁、锰、镍、铅、硅、钛等10种金属元素的含量。结果表明:各元素的质量分数在一定范围内与响应强度呈线性关系;方法用于分析其他校准样品,测定值的相对误差的绝对值不大于20%;方法用于测定2个实际WPCBs样品分析,硅的测定结果与氟硅酸钾容量法的基本一致,其他元素测定结果与电感耦合等离子体原子发射光谱法(ICP-AES)的基本一致。

       

      Abstract: The methods for determination of metal elements in waste printed circuit boards (WPCBs) required sample digestion, which was complex and time-consuming, while X-ray fluorescence spectrometry didn’t require sample digestion, but its quantification was inaccurate due to the lack of similar matrix standard samples. Based on this, geological standard materials with similar elemental composition to WPCBs were used as the substrate, and calibration curves were drawn with a series of calibration samples which prepared by adding epoxy resin and copper powder at different ratios into the above substrate. The study mentioned by the title was proposed. WPCBs was ground, passed through a 200 mesh (0.074 mm) sieve, and dried at 105 ℃. 5 g of the above sample was taken into a stainless steel mold, and boric acid was added to border. A circular discs with a diameter of 40 mm was made by a tablet machine with the pressure of 200 kPa and holding time of 20 s, and 10 metal elements, including silver, barium, chromium, copper, iron, manganese, nickel, lead, silicon, and titanium, were determined by wavelength dispersive X-ray fluorescence spectrometry (WD-XRF). As shown by the results, linear relationships between values of the mass fraction and the response intensity of the elements were kept in definite ranges. This method was used to analyze other calibration samples, and the absolute values of the relative error of the determined values were less than 20%. This method was used to analyze two actual WPCBs samples, the determination results of silicon were basically consistent with those by potassium fluorosilicate volumetric method, and the determination results of other elements were consistent with those by inductively coupled plasma atomic emission spectrometry (ICP-AES).

       

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