Simultaneous Determination of 14 Trace Elements in and Tin Ore with Open Acid Digestion by Inductively Coupled Plasma-Mass Spectrometry

Tungsten and tin ores have abundant paragenesis or associated elements with complicated composition. At present, the contents of these trace elements are detected respectively by the national standard methods for tungsten ore and tin ore, which have a great labour intensity and low efficiency. The tungsten ore and tin ore samples were dissolved by mixed acid at normal pressure and extracted by hydrochloric acid (50% HCl), and 14 trace elements of Li, Sc, Cr, Co, Ni, Cu, Pb, Zn, Rb, Mo, Cs, Sb, Bi and Th were simultaneously measured by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Three sample pre-treatment methods were compared among alkali fusion method, HCl-HNO₃-HF-HClO₄ method and HNO₃-HF-HClO₄ method. It was found that the HNO₃-HF-HClO₄ method is a simple operation and requires fewer reagents than traditional methods, which was chosen to dissolve the tungsten ore and tin ore samples. In the measurement, Rh and Re were selected as the internal standards to compensate for analytical signal drift. The results indicate that the detection limits of this method are 0.003-1.64 μg/g with a relative standard deviation (RSD, n=11) in the range of 0.1%-3.1%. The recovery rates were between 93.1%-104.3%. This method has been verified using practical tungsten and tin ore samples, and the results are in good agreement with the certified values. Comparing with the traditional treatment, this method has improved analysis efficiency, and is more suitable for analysis and detection of tungsten ore and tin ore samples in large batches.