Determination of cadmium, chromium, lead, silver and gold in Venezuelan red mud by atomic absorption spectrometry

Abstract

Standard reference materials and Venezuelan red mud samples were analysed by graphite furnace atomic absorption spectrometry, using a L'vov platform, to determine the Cd, Cr, Pb, Ag and Au content. The determinations were performed on both dissolved and solid samples. Conventional and microwave wet acid digestion procedures were tried to achieve optimum sample dissolution. Solid samples were diluted with urea prior to analysis. The results obtained showed that the best dissolution procedure entails microwave heating in closed vessels in the presence of a mixture of concentrated hydrochloric, hydrofluoric and nitric acids (9 + 5 + 6). Analyses of both dissolved and solid samples afforded results with acceptable accuracy and precision.