Abstract：Taphole clay is a kind of amorphous functional refractory material. The determination of Fe2O3, Al2O3 and CaO contents is helpful to control the product quality. There are many impurity components in the taphole clay, and the presence of silicon nitride and silicon carbide leads to the difficulty of fusion sample preparation, which limits the application of X-ray fluorescence spectrometry in the analysis of taphole clay materials. In this study, the impurity components were firstly decomposed followed by fusion sample preparation. Lithium hydroxide was used to decompose silicon nitride, while sodium nitrate and barium peroxide were used to decompose silicon carbide. Then lithium tetraborate-lithium metaborate mixed flux was used as the reaction base to isolate reactants and neutralize the excessive strong bases. Finally, the sample was fused to prepare the pieces. A method for the analysis of iron oxide, aluminum oxide and calcium oxide in taphole clay by X-ray fluorescence spectrometry with fusion sample preparation was established. The product of hot alkali reaction was analyzed by oxygen-nitrogen analyzer, and the optimum ratio of taphole clay to lithium hydroxide was determined. The test samples were characterized by blank experiments, contrast experiment, scanning electron microscopy (SEM), X-ray diffraction (XRD) and image Mapping. The results showed that lithium tetraborate could neutralize lithium hydroxide completely after melting at high temperature, and the main product of lithium metaborate was conducive to the analysis by X-ray fluorescence spectrometry. Lithium hydroxide could effectively decompose silicon nitride, avoiding the phenomenon of component aggregation caused by silicon nitride particles. So that the surface of the melt piece was clean and smooth. The contents of iron oxide, aluminum oxide and calcium oxide in taphole clay product samples were determined according to the experimental method, and the relative standard deviations (RSD, n=10) of determination results were between 0.28% and 4.6%. The differences between fluoride replacement EDTA titration method and inductively coupled plasma emission spectrometry method were both within the tolerance range of GB/T 6900-2016.
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