Analysis of ultra-low level rare earth elements in magnetite samples from banded iron formations using HR-ICP-MS after chemical separation

We have investigated two methods for the separation of rare earth elements (REEs) and Fe in magnetites from banded iron formations (BIFs), employing cation- and anion-exchange chromatography. The separated REEs were subsequently determined using a high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS). Our results indicated that 10 mL concentrated HCl was sufficient to completely separate all REES from Fe using anion exchange chromatography, whereas more than 30 mL of 6 mol L−1 HCl was required using cation-exchange. The recovery of REEs using both methods was 100% ± 5%. The procedure blanks for the REEs using the anion method were lower than those using the cation method. Our results indicated that the anion exchange method has advantages over cation exchange for the analysis of ultra-low level REEs in magnetites. The proposed methods were tested using the reference material FER-2.