Determination of Se and Te by hydride generation-inductively coupled plasma mass spectrometry after mixed-acid digestion of tungsten ores

Abstract

Se and Te in tungsten ores are important parameters for exploring the metallogenetic process of tungsten ores; however, due to their high refractory, low abundance, extreme volatilization, as well as the complex matrix interference during analysis, it is a challenge to accurately determining their concentrations in tungsten ores. This study presents a method of combining hydride generation device with inductively coupled plasma mass spectrometry (HG-ICP-MS) to determine the contents of Se and Te in tungsten ores. As a pre-processing step, tungsten ores were dissolved in the mixture of HF + HNO3 + HClO4 and microwaved for digestion. The analytical results show that the main matrix components (K, Na, Ca, Mg, Fe, Mn and Pb) in tungsten ores have no interference, and the interference of W, Cu, Zn and Bi can be eliminate by adding an appropriate amount of Fe3+. The method was used to test 6 samples with different tungsten concentrations. Compared with the results of hydride generation atomic fluorescence spectrometry (HG-AFS) method, the mean values of HG-ICP-MS method showed a good consistency and the relative mean deviations of Se and Te contents were in the range of −5.2%­ to 6.2% and − 3.8%­ to 3.4%, respectively. The values of Se, Te and Te/Se ratio determined from various geological samples (30 soil and sediment samples, 30 granite samples, 25 poly-metallic sulfide ore samples and 29 tungsten ore samples) highlight their potential prospecting in the metallogenetic process of tungsten ores.