ZIRCONIUM AND HAFNIUM DETERMINATION BY ENERGY-DISPERSIVE X-RAY-FLUORESCENCE WITH SOLID-PHASE PRECONCENTRATION

Two preconcentration methods has been developed for simultaneous deter mination of zirconium and hafnium by energy dispersive X-ray fluoresce nce (EDXRF). The first method is a liquid-solid extraction procedure w ith the use of an anionic exchange resin modified with xylenol orange. The second is a precipitation procedure carried out in the presence o f lanthanum. Both methods permit significant enhancement of sensitivit y in comparison with direct measurement in the aqueous phase. The appl icability of both procedures for the preconcentration of Zr and Hf pri or to their determination by EDXRF was demonstrated by analyzing synth etic mixtures and a sample of zirconium ore. The results obtained with the use of the modified resin show relative standard deviation of abo ut 4% and good agreement with those obtained by spectrographic analysi s. (C) 1997 Published by Elsevier Science B.V.