Analysis of cerium oxide by arc atomic emission spectrometry

Abstract

Materials based on rare earth elements (REE) are of great importance due to their unique chemical and physical properties, but the effectiveness of their use depends on the quality of raw materials. Therefore, further development of the methods of analytical control in relation to rare-earth materials is aimed at increasing the accuracy and sensitivity of the methods, as well as at expanding the nomenclature and concentration range of the determined elements. Cerium oxide is used in glasses, ceramics, catalysts, phosphors, composite and scintillation materials, as well as in medicine. The problem of developing a new arc spectral method is extremely urgent to match modern requirements for the accuracy and sensitivity of the impurity determination for monitoring the purity of cerium oxide. A technique for arc atomic emission analysis of cerium oxide which meets modern requirements for the accuracy and sensitivity of the impurity determination has been developed. The range of impurities to be determined is significantly expanded compared to the standardized technique of the 1970s. The goal of this work is to study and develop a modern method for arc optical emission spectral analysis of cerium oxide using the instrumental capabilities of the atomic emission complex «Grand Globula». To specify compromise conditions for the determination of 15 REE impurities and 19 elements more, analytical lines were selected and the dependence of their intensity on the operating mode of the generator, the shape and size of the electrodes, the interelectrode distance, the ratio of the masses of the analyzed sample and graphite powder, as well as on the presence of various carriers (Ga2O3, NaCl, NaF, KCl, S, GeO) was analyzed. Application of the considered methodological approach to the selection of conditions made it possible to develop a method for spectral analysis of cerium oxide without preliminary dissolution of the sample with an extended range of determinable impurities. When studying the curves of the impurity evaporation, an exposure time was chosen to be sufficient for their complete evaporation (100 – 120 sec). The study has shown the 0promising character and feasibility of the developed arc spectral techniques applicable to the analysis of REE-based materials as an alternative to the methods for analysis of solutions. The metrological characteristics of the proposed procedure for the analysis of cerium oxide were evaluated in comparison with the standardized technique.