Simultaneous Determination of 15 Elements in Lead-Zinc Ore by Inductively Coupled Plasma-Atomic Emission Spectrometry

The process of sample preparation is affected by many different factors in multi-element determination for lead-zinc ore. However, single-factor experiment design cannot provide a reasonable solution for the simultaneous optimization of multiple-factor experiments. In this study, minerals were dissolved by hydrochloric acid-nitric acid. The effect of digestion conditions was studied. Ratio and volume of the mixed acids as well as time and temperature of the digestion were optimized by orthogonal test and range analysis. The conditions of digestion were optimized as: ratio and volume of the mixed acids at 3:1 and 10 mL, respectively, time and temperature of the digestion of 120 min and 90℃, respectively. The contents of 15 major and trace elements (Pb, Zn, Cu, Mn, As, Ag, Bi, Cd, Co, Ni, Ga, In, Mo, Ge and Sb) were determined simultaneously by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). Under optimal conditions, the method was verified by certified national reference material GBW 07165. The results show that the precision (RSD, n=12) and accuracy are less than 5% for most elements, and the detection limit is 0.0019-0.048 μg/g. In addition, as the lead-zinc ore usually exits in the form of sulfide, the accuracy and feasibility of the method can be verified by a series of national standard sulfide materials. The results were consistent with the certified values within uncertainties. After using the proposed method to analyze large quantities of lead-zinc ore samples collected from Hunan, the qualification rates for standard samples and blind samples are 100% and 97%, respectively. This method optimizes the experimental conditions, and solves the complex problem of sample pretreatment. The method has many advantages, including low consumption of reagents, green environment and simultaneous determination of multi-elements, which indicates that it is an accurate and practical method to simultaneously determine the content of lead and zinc.