摘要： 在使用能量色散X射线荧光光谱仪定量分析钼铜矿中低含量Cu和Mo元素过程中，X光管的原级谱对测量结果影响非常大。为了降低这一影响，采用蒙特卡洛软件模拟了用Ag，Cu和Mo，Ti三种材质的滤片，在不同厚度情况下对原级谱的影响。模拟结果显示，1 mm Ti滤片测铜钼元素效果优于0.2 mm Ag滤片、0.02 mm Cu和0.1 mm Mo滤片。根据模拟结果，在实验室用三种滤片对样品进行了实测，谱线图对比显示，用Cu+Mo作滤片测钼元素时，本底计数大于200，用Ag和Ti作滤片测钼元素，几乎没有本底影响。但相同的样品，用Ti作滤片测得钼最高计数为800左右，而用Ag作滤片时测得钼最高计数为300左右。由此可见，用Ti作滤片测钼元素时，X光管原级谱对被测量元素的干扰影响小，其本底低于用银滤片和铜钼滤片。Ti滤片在降低本底影响的同时，钼的计数率最高，说明射线强度损失最少。用Cu+Mo作滤片测铜元素时，铜最高计数为300，用Ag作滤片时铜最高计数为180左右，而用Ti作滤片铜最高计数为500左右。由此可见，在铜元素含量较低时，用Ti作滤片测铜元素，铜的计数率最高，射线强度损失最少。通过公式计算显示：用1 mm Ti滤片测钼铜矿中铜的检出限为5.63 mg·kg-1，钼的检出限为1.39 mg·kg-1，检出限明显降低。采用不同含量的标准样品进行测量与化学分析拟合, 通过工作曲线可见，高、低含量的样品均具有良好的线性关系，误差水平符合正常化学分析误差标准, R2为0.99及以上，说明1 mm Ti滤片测量精密度高。同一个样品进行多次重复测量，其Cu元素的RSD(%)=0.59，Mo元素的RSD(%)=0.3，均小于1，表明仪器测量稳定性好，样品测试结果具有重现性。研究结果为使用能量色散X射线荧光光谱仪测定钼铜矿中的钼和铜滤光片的选择及其厚度的确定提供了可信的依据，推荐选用1 mm Ti滤片。经过实际现场的检验。该方法稳定可靠，具有重要的实际应用价值。
关键词：能量色散X射线荧光光谱仪；原级谱；铜钼元素；滤光片；检出限
Abstract：In the process of quantitative analysis of low content of Cu and Mo in molybdenum-copper ore by energy dispersive X-ray fluorescence spectrometry, the original spectrum of X-ray tube has a great influence on the measurement results. In order to reduce this effect, Monte Carlo software was used to simulate the influence of filters of Ag, Cu+Mo and Ti on the original spectrum under different thickness conditions. The simulation results showed that the effect of measuring copper and molybdenum elements with 1mmTi filter is better than that of 0. 2mm Ag filter, which is better than the case of using 0.02 mm Cu and 0.1 mm Mo as filters. According to the simulation results, the thickness of the three kinds of filters was measured. By comparing atlas of spectrolines showed that When Cu+Mo is used as a filter to measure molybdenum, the background count is greater than 200, and when using Ag and Ti as a filter, the molybdenum element is measured, and there is almost no background influence. However, for the same sample, the highest count of molybdenum was about 800 when Ti was used as the filter, and the highest count of molybdenum was about 300 when using Ag as the filter. It can be seen that when the molybdenum element is measured by using Ti as a filter, the original spectrum of the X-ray tube has little influence on the interference of the measuring element, and the background thereof is lower than that of the silver filter and the copper-molybdenum filter. The Ti filter has the highest count rate of molybdenum while reducing the background effect, indicating that the ray strength loss is the least. When Cu+Mo is used as a filter to measure copper, the highest count of copper is 300. When using Ag as a filter, the highest count of copper is about 180, while the highest count of copper using the filter is about 500. It can be seen that when the content of copper is low, the use of Ti as a filter to measure copper elements has the highest count rate of copper and the least loss of ray strength. The calculation by formula showed that the detection limit of copper in molybdenum-copper ore is 5.63 mg·kg-1 with 1 mm Ti filter, and the detection limit of molybdenum is 1.39 mg·kg-1, and the detection limit is significantly reduced. Using different standard samples for measurement andchemical analysis fitting, the working curve shows that the high and low content samples have a good linear relationship, the error level meets the normal chemical analysis error standard, R2 is 0.99 and above, indicating that 1 mm Ti is passed. The measurement results by using 1 mm Ti filter are highly Precision. Selecting any one of the production samples for repeated measurements, the RSD (%) of the Cu element is 0.59, and the RSD (%) of the Mo element is 0.3, which is less than 1, indicating that the instrument has good measurement stability and the sample test results are reproducible. In this paper, the determination of molybdenum and copper in molybdenum copperore by energy dispersive X-ray fluorescence spectrometry, Monte Carlo simulation analysis provides a credible basis for the selection of filters and the determination of their thickness. A 1 mm Ti filter was selected and tested on-site. The method is stable and reliable and has important practical application value.
