Determination of Major and Minor Elements in Ferroniobium by X-Ray Fluorescence Spectrometry with Pre-Oxidation and Fusion Sample Preparation

To simplify the cumbersome steps in traditional wet method as well as solve the problems of crucible corrosion, large matrix effect, and poor accuracy of niobium element determined by X-ray fluorescence spectrometry for detection of major and minor elements in ferroniobium, the conditions of pre-oxidation and instrument working were optimized. Lithium tetraborate, lithium carbonate, and vanadium pentoxide were used for pre-oxidation, lithium tetraborate was used for preparation of glass sheets by fusion, and X-ray fluorescence spectrometry was used to quickly determine niobium, silicon, phosphorus, aluminum and titanium elements, simultaneously. The 2.000 0 g of lithium tetraborate, 1.000 0 g of lithium carbonate, 0.500 0 g of vanadium pentoxide, and 0.200 0 g of sample were mixed thoroughly, and pre-oxidized at 950 ℃ for 30-40 min. After cooling to form a solid ball, the mixture was placed into a platinum yellow crucible containing 4.000 0 g of lithium tetraborate, and 0.225 g of 300 g·L^-1 potassium iodide solution was added dropwise. The above mixture was pre-melted for 120 s, melted for 720 s, and settled for 10 s at 1 050 ℃. Glass sheets were formed and demolded after cooling, and determination was carried out according to the optimized instrument working conditions. It was shown that linear relationships between values of the mass fraction and the fluorescence intensity of the 5 elements were kept in definite ranges, with correlation coefficients greater than 0.999 0. RSDs (n=6) of the determined values of the 5 elements in standard samples were found in the range of 0.26%-1.5%. The proposed method was applied to the analysis of standard samples and self-made standard samples. Compared with the outsourced determined values, the absolute values of biases were within the allowable tolerance range specified by the series standards GB/T 3654—2019.