Is removal of copper by electrolysis from copper minerals an appropriate method for determination of trace elements?

摘要

The trace elements content in the copper mineral chalcanthite (CuSO_4 ? 5H_2O) was determined using k_0-INAA before and after quantitative removal of copper. To avoid the interference of the matrix element, a method for electrolytic separation of copper was used. The distribution of 47 elements (with intermediate/medium and long-lived radionuclides) present in the studied mineral was investigated. The main advantage of the proposed method is the possibility to determine the content of several elements (Al, Dy, K, Mg, Mn, Pt, Re and V) via their short-lived nuclides after the electrolysis of Cu as a result of the elimination of interferences from the matrix element. In addition, the limit of detection for some elements (Ga, K and W) is lower in the electrolyzed solution compared to their corresponding values determined by k_0-INAA. However, the results showed that electrolysis was not an appropriate method for determination of some trace elements (As, Na, Sb, Pt and Zn) at low concentration level due to contamination from the Pt-electrode or inadequate purification of the glassware used, adsorption/ desorption on glassware (e.g. Na, Sb, Se), or losses during evaporation of the solution (heated to about 80 ℃) to ～2mL(e.g. Se).