China Nonferrous Metallurgy

Due to the large amount of sulfur and silicon elements in bismuth concentrate, the silver content in bismuth concentrate can not be completely dissolved by aqua regis, resulting in incomplete sample dissolution, which may result in low measurement results. In this study, perchloric acid and ammonium bifluoride were added in sample pretreatment to dissolve sulfur and silicate compounds, and then the content of silver in bismuth concentrate was determined by flame atomic absorption spectrometer (AAS), which effectively solved the influence of high sulfur and silicon content in bismuth concentrate on sample dissolution and determination. During the test, bismuth concentrate was dissolved with 2.0mL perchloric acid, 0.2g ammonium bifluoride and aqua regis system. Under the condition of 20% HCl medium, the silver content of bismuth concentrate samples was measured by flame atomic absorption spectrometer. The results showed that the detection limit of this test method was 0.0066μg/mL. It is lower than the lower limit of 0.022μg/mL, which indicates that this test method is feasible and can meet the determination requirements of silver content in bismuth concentrate. The relative standard deviation (RSD, n=7) was 0.20% to 1.95%, and the recoveries were 97.7% to 105.0%. There is no obvious matrix effect interference in the synthetic element interference determination. The method is suitable for the determination of 50.0g/t~10000.0g/t silver in bismuth concentrate, which provides a more simple and practical method for enterprises and testing institutions to determine the silver content in bismuth concentrate.