Rapid analysis of gold and sliver in blister copper by nitric acid digestion prior to determination by atomic absorption spectrometry

A rapid method for the analysis of gold and sliver in blister copper by atomic absorption spectrometry was proposed. Nitric acid was used to digest blister copper instead of commonly used sulfuric acid. This avoided forming the salt of copper sulfate in the filtration process when the volume of the mixture is very small. Thus, the time of filtration was saved. After filtrating, aqua regia was used to digest the residue and acidize the filter liquor. Two parts of gotten solution were directly determined by atomic absorption spectrometry. The cycle of analysis was shortened compared with sulfuric acid-fire assay. The proposed method was successfully applied to determine gold and sliver in blister copper, and the results were in good agreement with those obtained by lead fire assay.