Determination of Silver, Lead, Cadmium, Mercury and Arsenic in Copper Concentrate by Inductively Coupled Plasma Atomic Emission Spectrometry with Microwave Digestion

A method for determination of silver, lead, cadmium, mercury and arsenic in copper concentrate by inductively coupled plasma atomic emission spectrometry (ICP-AES) with microwave digestion was established. Copper concentrate sample of 0.2 g that had been dried to constant weight was digested with 6 mL of hydrochloric acid, 2 mL of nitric acid and 0.5 mL of hydrofluoric acid according to the microwave digestion procedure. After that, it was cooled to room temperature, and the resulting solution was made its volume up to 100 mL with water, moreover, individual samples with high carbon content must be dry filtered to remove carbon. 328.068 nm of silver, 220.353 nm of lead, 214.438 nm of cadmium, 194.227 nm of mercury and 193.759 nm of arsenic were used as analytical spectral lines, and silver content of quality index and the contents of lead, cadmium, mercury and arsenic of environmental protection indexes were determined by ICP-AES. The interference of iron and copper elements was eliminated by iron and copper matrix matching. It was showed that the linear relationships between mass concentrations of silver, lead, cadmium, mercury and arsenic and their corresponding emission intensities were kept in the definite ranges, with detection limits (3s) of 0.001 5, 0.030, 0.014, 0.006 0 and 0.037 mg·L^-1, respectively. The proposed method was used for analyzing the national reference materials and capability verification samples, and the determined values were consistent with the certified values or median values, with RSDs (n=11) in the range of 0.63%-1.8%. The actual samples of copper concentrate were analyzed by this method, and the results were consistent with that of the standard methods.