波长色散X射线荧光光谱法快速测定铂铑合金中铂和铑的含量

摘要

Background: Pt-Rh alloy is widely used in industry. Therefore, it is of importance to determine the content of platinum and rhodium in Pt-Rh alloy rapidly. Purpose:This study aim is to establish a rapid and accurate analysis method for the Pt-Rh alloy measurement. Methods: Wavelength dispersive X-ray fluorescence (XRF) spectrometry was applied to the measurement of platinum and rhodium in Pt-Rh alloy by setting 60 kV, 50 mA as excitation conditions, and using 100mm brass filter, 300mm pitch collimator, PX10 analyzer crystal and scintillation detector to measure Laline of Pt and Kaline of Rh for analysis. In order to eliminate interference caused by sample cup mask, collimator mask of 27 mm in diameter were taken for measurement. The empirical coefficient method was used to correct matrix effect and set up calibration curves of Pt and Rh. Results:The calibration curves have better linear correlations and less K and RMS (Root Mean Square) values. The experimental results show that the relative errors of Pt and Rh are less than 0.09%and 0.54%, the relative standard deviations are 0.11%and 0.17%(n=10), and the detection limits are 208mg·g−1 and 37mg·g−1, respectively. The measurement time of one single sample is only 74 s. The relative errors of Pt and Rh in preparation of Pt-Rh alloy measured by this method contrast the formula values are less than 0.06% and 0.20%, respectively. The contents of Rh in samples of diluting and smelting Pt-Rh alloy are measured. Compared with the calculated value, the relative error is less than 0.29%. Conclusion: This method can meet the demand of analyzing large quantities of Pt-Rh alloy samples and provide accurate and reliable scientific data for production practice.%采用波长色散X射线荧光(X-ray fluorescence, XRF)光谱法对铂铑合金中Pt和Rh的含量进行测定，建立了一种Pt和Rh的分析测量方法。实验设定波长色散XRF光谱仪激发电压为60 kV、电流为50 mA，采用100mm的黄铜滤光片、间距300mm的准直器、PX10分光晶体和闪烁探测器对Pt的La线和Rh的Ka线进行分析测量；为消除样品杯罩产生的干扰使用直径27 mm的准直器面罩。应用经验系数法对基体效应进行了校正，建立了Pt和Rh的校正曲线，其K值和RMS值（均方根偏差）较小，线性相关性较好。分析结果表明， Pt 和 Rh 的相对误差分别小于0.09%和0.54%，相对标准偏差分别为0.11%和0.17%(n=10)，检出限分别为208mg·g−1和37mg·g−1，该方法能准确可靠地测定铂铑合金中Pt和Rh的含量，单样分析时间仅需74 s。将该方法应用到铂铑合金配制生产过程中，Pt和Rh的测定结果与配方值的相对误差分别小于0.06%和0.20%。在铂铑合金稀释熔炼中，对稀释后样品的Rh含量进行测量，其测量结果与计算值的相对误差低于0.29%。该方法能够满足大批量铂铑合金样品的分析需求，为生产实践提供准确可靠的科学数据。