ICP-MS Determination of Impurity Elements in V-Ti Magnetite

Twelve impurity elements, including As, Pb, Sn, Sb, Zr, Bi, Zn, Cu, Co, Ni, Cr and Mo, in vanadium and titanium bearing magnetite were determined by ICP-MS. Microwave assisted sample digestion with HF and HNO3 was shown to be very effective for dissolution the magnetite sample with high contents of TiO2, SiO2, V2O5 and Al2O3. Mass spectral interferences were eliminated by preparation of matrix blank solution with high purity iron, titanium and vanadium (65% Fe+20% TiO2+10% V2O5), and by selection of appropriate istopes for each of the analyte elements. Interference due to matrix effect was overcome by addition of rhodium solution as internal standard. Values of detection limit (3s/k) for the 12 elements were found in the range of 0.11 to 1.92 μg·L-1. Precision was tested by analyzing a same magnetite sample for 8 determinations, values of RSD′s calculated were all less than 5%. As shown by the results obtained by analyzing 4 CMR′s with the present method, good consistency with certified values was attained. In addition, the results of the 12 elements in V-Ti magnetite sample determined by this method were found to check quite well with the results found by ICP-AES.