ICP EMISSION SPECTROMETRIC ANALYSIS OF RARE-EARTH ELEMENTS IN PERMANENT-MAGNET ALLOYS

An analytical method for the determination of rare earth elements (REE ) in a NdFeB permanent magnet alloy by ICP emission spectrometry is de scribed. Spectral interferences, arising from overlapping, as well as matrix effects have been studied. Considering spectral interferences, sensitivities of spectral lines, background intensities and the chemic al composition of the sample investigated, optimum spectral lines for each REE have been selected. Because of an unfavourable concentration ratio in samples of a NdFeB permanent magnet alloy, a preliminary sepa ration of matrix elements from rare earth elements by ion chromatograp hy is necessary. Different modes of elution (isocratic and gradient) w ith alpha-hydroxy-isobutyric acid and different columns (NUCLEOSIL, SU LFOPROPYL SI-100, DIONEX HPIC-CS3) have been tested. Optimum separatio n conditions have been chosen for each element and the separation effi ciency at equal or different concentrations of the selected elements h ave been established. Although the separation of REEs resulted in part ly overlapping peaks, the ratio between analyte and interferent is imp roved and the spectral interferences are diminished. The results obtai ned are in good agreement with certified values.