Determination of Multi-elements in Polymetallic Ores by ICP-OES with Mixed Acids and Nitric Acid Microwave Digestion

Different pretreatment methods should be used for quick and accurate determination of major and minor elements in different types of polymetallic ores. In this study, five types of polymetallic ores including Pb-Zn, Sn, Mo, V, and Cu-Ni polymetallic ores were collected from typical metallogenic areas of China. Comparison of microwave digestion using mixed acids of hydrochloric-nitric-perchloric-hydrofluoric-sulphuric acids with digestion using nitric acid only was performed. Nine elements, Cu, Pb, Zn, Sn, W, Mo, Mn, Ti, and V were determined by the Inductively Coupled Plasma-Optical Emission Spectrometry technique. Analytical results of National Standards Reference indicate that digestion with a mixture of five acids has a long digestion time and can simultaneously determine the 6 elements of Cu, Pb, Zn, Mo, Mn, and V. Digestion with nitric acid needs only 1 h and can determine 4 elements, Cu, Pb, Zn, and Mo. Two methods have good accuracy and precision (RSD < 5%) and low detection limits of 5.3-30 mg/kg, which are suitable for application in geological analyses. However, neither of these two methods are suitable for analyzing Sn, W, and Ti, because these elements cannot be digested completely by acids.