Simultaneous Determination of Sn, W, Mo, Cu, Pb and Zn in Tin Ores by Inductively Coupled Plasma-Atomic Emission Spectrometry

The work involved to accurately determine the major and minor elements in tin ore, which contains large quantities of paragenetic and associated elements is extremely challenging. It is difficult to decomposed tin ore and the Sn, W and Mo are easily precipitated in HCl solution. A highly efficient analytic method which is capable of simultaneously determining Sn, W and Mo in tin ores by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) is reported in this paper. The ore samples are melted with Na₂O₂ and acidized by mixed tartaric acid, hydrochloric acid and hydrogen peroxide. Co is used as the internal standard element. The linear range of this present method is 0.00-40.0 mg/L, and the detection limits are 10 mg/kg for Sn, 30 mg/kg for W, 3.3 mg/kg for Mo, 12 mg/kg for Cu, 15 mg/kg for Pb and 40 mg/kg for Zn, respectively. The relative standard deviation (RSD,n=9) is less than 5.0%. All results of the National Standard Reference Materials determined by this method are consistent with the certified values. The samples can reach complete melting by using Na₂O₂ and the step to evaporate the HF acid to remove Si can be avoided, which results in reducing the processing time of samples. The application of mixed tartaric acid-hydrochloric acid-hydrogen peroxide system assists Sn, W and Mo to form stable complexations, which solves the problem of lower determining results due to forming precipitations of tungstenic acid, molybdic acid and stannic acid in HCl solution.