铜精矿化学成分分析实验室间比对结果评价和离群值原因分析

铜精矿成分分析是判定其品质的重要手段,尤其是主元素铜的分析.目前,测定铜精矿中铜含量的主要分析方法有碘量法、电感耦合等离子体发射光谱法(ICP-OES)、火焰原子吸收光谱法(FAAS)、X射线荧光光谱法(XRF)、电解重量法等.为确保检测标准量值统一、准确、可靠,本文组织开展了铜精矿中铜镁铅锌的测定实验室间比对活动.通...

Evaluation of the Interlaboratory Comparison Results of the Chemical Composition of Copper Concentrates and Analysis of the Causes of Outliers

BACKGROUND: Composition analysis of copper concentrate is an important method to determine its quality, especially the analysis of the main element copper. Currently, the main analytical methods for the determination of copper content in copper concentrate include iodometry, inductively coupled plasma-optical emission spectrometry (ICP-OES), flame atomic absorption spectrometry (FAAS), X-ray fluorescence spectrometry (XRF), and electrolytic gravimetric methods.OBJECTIVES: To ensure the uniformity, accuracy, and reliability of the standard values, interlaboratory comparison activities for the determination of copper, magnesium, lead, and zinc in copper concentrate were organized.METHODS: Through the statistical analysis of the test results of the participating laboratories, the technical level and ability of the participating laboratories in the determination of copper, magnesium, lead, and zinc in copper concentrates were evaluated.RESULTS: The results showed that most laboratory results were satisfactory, the satisfaction rate of copper in the copper concentrate was 92.9%, and the average satisfaction rate of copper, magnesium, lead, and zinc was 89.0%. The outliers in a few laboratories were mainly attributed to sample pretreatment, lack of understanding and mastering of the analytical methods by the testing personnel, and other related factors, such as the instrument status.CONCLUSIONS: Because of incomplete sample decomposition, the alkali leaching method could not be used for pretreatment of copper concentrate. Additionally, the alkali fusion method is not recommended for copper concentrate pretreatment because of its complicated process and matrix interference. Acid dissolution titration is preferred as a pretreatment method for the determination of copper in the copper concentrate. The acid-dissolution ICP-OES method for simultaneous determination of Cu, Mg, Pb, and Zn in the copper concentrate is efficient and rapid with satisfactory results. However, further experiments are required to investigate their stabilities.