Determination of High Content Silver in Lead Powder by Flame Atomic Absorption Spectrometry under Hydrochloric Acid Medium

Abstract

Some lead powder has a high content of silver (>1000 μg/g), organic matter and sulfur, which will result in lower Ag content during wet pretreatment because Ag is insoluble, easy to wrap, and easy to precipitate. In view of these problems, the digestion method was optimized and the optimum conditions for analyzing silver in lead concentrate were determined and are reported in this paper. Sulphur was removed by hydrochloric acid. The sample was then dissolved in nitric acid-hydrofluoric acid-perchloric acid. In 20% hydrochloric acid medium, silver content was determined by the Flame Atomic Absorption Spectrometer at the wavelength of 328.07 nm. Under these conditions, the samples are completely digested, the extract liquid is clear and no precipitation remains. The method was tested by the lead powder national standards (GBW07167 and GBW07172) and standard sample Pb-3. The method has a precision of 1.0%-3.2% (RSD, n=12). The relative error between these results and certified values is less than 1%. The stability of the sample solution prepared by this method was good, the analysis was rapid and the silver content up to 3000 μg/g can also be measured.

Keywords

• lead concentrates powder
• silver
• acid dissolution
• flame atomic absorption spectrometry