粉末压片-X-射线荧光光谱法分析砂岩型铀矿制样中粘结剂用量的探讨

由于砂岩型铀矿的成矿特性，样品粉末的内聚力小，采用直接压片法有时难以成型，样片表面常见裂纹，上机测量易碎裂。混合压片法适应性强，制样成功率高，但常见的问题是样品经粘结剂稀释会影响元素的检出限及结果的准确性。本文对粉末压片-X射线荧光光谱法测定砂岩型铀矿地质样品时，前期制样中添加粘结剂的比例进行了研究。试验按照不同比例在铀矿石标准物质GBW04101、GBW04102中添加粘结剂，在扫描电镜下观察到随着粘结剂用量的增加样片表面的光滑度及致密度都呈上升趋势，在X-射线荧光光谱仪上对主量元素进行测定后发现X射线强度在粘结剂添加量大于0.2 g时明显下降，经与GBW04101、GBW04102标准值进行对比后优选出粘结剂与样品的最佳比例为1：20，在此比例下制成的样片光滑平整，不易碎裂，用粉末压片-X射线荧光光谱法进行测定，标准物质测定结果的相对误差为0.56%～6.76 %，相对标准偏差(RSD，n=12)为0.013 %～7.68 %，均达到了《地质矿产实验室测试质量管理规范》DZ/T 0130-2006的要求。本文为粉末压片-X射线荧光光谱法分析砂岩型铀矿地质样品提供了可靠的实验参考依据。

Analysis of Binder Content in Sandstone Type Uranium Ore Sample Preparation by Powder Tablet X-ray Fluorescence Spectrometry

ABSTRACT Due to the mineralization characteristics of sandstone type uranium deposits, the cohesive force of sample powder is small, and it is sometimes difficult to form using direct compression method. The surface of the sample is often cracked, and it is easy to break when measured on the machine. The mixed compression method has strong adaptability and a high success rate in sample preparation, but a common problem is that diluting the sample with adhesive can affect the detection limit of elements and the accuracy of the results. In this paper, the proportion of binder added in the early sample preparation for the determination of sandstone type uranium ore geological samples by powder tablet pressing X-ray fluorescence spectrometry is studied. In the test, binders were added to uranium ore reference materials GBW04101 and GBW04102 in different proportions.Under scanning electron microscope, it was observed that the smoothness and density of the sample surface increased with the increase of the amount of binder. After measuring the main elements on the X-ray fluorescence spectrometer, it was found that the X-ray intensity decreased significantly when the amount of binder was greater than 0.2 G After comparing the standard values of GBW04102, the optimal ratio of binder to sample is 1:20. The sample prepared under this ratio is smooth and flat and not easy to break. It is determined by powder tablet pressing X-ray fluorescence spectrometry. The relative error of the determination results of reference materials is 0.56% ~ 6.76%, and the relative standard deviation (RSD, n = 12) is 0.013% ~ 7.68%, All of them have met the requirements of quality management specification for laboratory testing of Geology and mineral resources (DZ / T 0130-2006). This paper provides a reliable experimental reference for the analysis of geological samples of sandstone type uranium deposits by powder tablet pressing X-ray fluorescence spectrometry.KEY WORDS: sandstone type uranium deposit; powder tablet pressing method; binder; X-ray fluorescence spectrometer