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Simultaneous determination of rare earths by x‐ray fluorescence spectrometry using a fundamental parameters method

Abstract:

Concentrates extracted from a lateritic mineral deposit were analysed for their rare earth (RE) content by energy‐dispersive x‐ray fluorescence (XRF) spectrometry. The L emission lines of the lanthanides were excited with the 22.1 keV Ag K radiation from an annular Cd‐109 radioisotope source. The problem of the extensive overlap of the L lines were solved by the AXIL program for deconvolution of XRF spectra. Individual REs were quantified by preparing semi‐transparent pellets of the concentrate with starch which served as dilutant and binder. This allowed correction for sample absorption with the light matrix program of the QXAS analysis package based on the fundamental parameter method. The method allowed the simultaneous determination of 12 rare earths contained in the sample, with a reproducibility of 2.0–29% and accuracy in the range 1.5–24% relative error without the use of standard materials. Detection limits achieved were in the range of 340 ppm for the heavy REs and 4000 ppm for the light REs. Copyright © 1993 John Wiley & Sons Ltd.