Разработка методики рентгенофлуоресцентного определения содержаний Ta в горных породах разнообразного состава

Abstract

The technique has been developed for the quantification of small tantalum concentration in rocks with X-ray wavelength dispersive spectrometer TIGER (Bruker AXS, Germany). The optimum conditions have been chosen for registrating the characteristic radiation of tantalum and background positions. Ta L β 1 - line has been selected as an analytical line. To accurately determine the tantalum concentration the contribution of overlapping lines to the experimental intensity of the analytical line has taken into account. 1-2 g of sample has been pressed into tablet by the hydraulic press HTP-40. Metrological studies showed that the accuracy in the determination of tantalum contents for the developed technique meets the requirements for methods of III accuracy category. The Ta detection limits calculated for Ta L α and Ta L β lines considered, were 3.1 and 2.6 ppm, respectively. Ta concentration in granite pegmatite samples has been quantified. The samples of the highest tantalum content have been investigated by powder diffraction and X-ray microprobe analysis. The X-ray diffraction method turned out to be insensitive to the detection of mineral phase of tantalum niobates, while micro-XRF allowed detecting its presence in tourmaline grains. Key words : X-ray fluorescence analysis, WDXRF, determination of Ta, rocks, overlapping lines, empirical corrections method, powder diffraction. (Russian) DOI: http://dx.doi.org/10.15826/analitika.2014.18.1.002 D.S. Suvorova, E.V. Khudonogova, A.G. Revenko Institute of the Earth's crust SB RAS , Irkutsk , Russian Federation