Application Skills on Determination of Geological Sample by X-ray Fluorescence Spectrometry

Abstract

X-ray Fluorescence Spectrometry (XRF) has such advantages as simple sample preparation, green environmental protection and the simultaneous determination of multiple elements and is widely used in the exploration geochemistry analysis field. Pressed Powder X-ray Fluorescence is the dominant method for its rapid and economic application. However, when large quantities of samples are being tested, if the analysts' measurements conditions are improperly selected or the working curve correction is unreasonable, gross error will be caused in the measurement result. The technology problems encountered in the test of a certain element in geological samples is given a detailed analysis and discussed in this paper. Vanadium is chosen as an example, indicating that the choice of SC detector expounds the importance of correct selection of measurement conditions. For example, the detection of iron in silicate describes the effect of regression curves which work differently on the measurement results. For the determination of low content of niobium and tantalum in geological samples, work curves should be reasonably returned according to the practical situation, and the samples after testing should be compared with chemical methods, then the result can be considered as consistent. In soil, stream sediment, rocks and other geological samples, mutual interference between elements exists. The common rock forming element titanium was used as an example to prove that aluminum and iron in samples does have the absorption and enhancement effect on the spectral lines of titanium. For common carbonate samples, in the measuring of chloride and chromium the enhanced absorption effect of calcium oxide must be considered, and calcium oxide must be added as its enhanced absorption correction term, in order to ensure reliable measurement results. Finally, the problem of pollution of sulfur and the preventive measures were also analyzed. Some common measurement problem of silicate, carbonate in geological samples is presented, and the solution to the actual production is discussed.

Keywords

• geological sample
• x-ray fluorescence spectrometry
• measurement conditions
• standard curve
• correction term