A framework for determining mineralogy and chemical composition of industrial mold powders

Abstract

Mold powders are essential in continuous casting of steel as they serve as a lubricant, protect the steel from oxidation, provide thermal insulation, absorb impurities, and control heat transfer between steel and mold. Industrial mold powders comprise various constituents and raw materials with distinct mineralogical and crystallographic features. This study presents a framework for accurate quantitative mineralogical analysis of SiO2–CaO–CaF2–Na2O–Al2O3 mold powders for peritectic steel grades. Advanced characterization techniques, including Scanning Electron Microscopy based Automated Mineralogy (SEM–AM), image analysis, and Electron Probe Microanalyzer (EPMA) were employed to identify and quantify mineralogical species. Quantitative X-Ray powder Diffraction (QXRD) was applied to determine amorphous content and crystalline phases, further confirming the mineralogy. A reference powder with known composition was prepared in the laboratory to validate the characterization techniques. Accurate analysis methods for bulk chemical composition measurements are proposed including X-Ray Fluorescence (XRF), Fluorine Ion Selective Electrode (FISE), Flame Atomic Absorption Spectrometry (F-AAS), and combustion analysis (LECO) with expansion of Simultaneous Thermal Analysis with Mass Spectrometry (STA–MS) to investigate free carbon and carbon-bearing components. Results demonstrate that this multimethodological framework is suitable for characterizing and quantifying raw materials with sufficient accuracy despite material complexity. Mineralogical analysis identified feldspars, pyroxenes, melilites, fluorides, carbonates, oxides, silicates, amorphous phases, and a free carbon source as the main constituents, and specific ratios of these raw materials are described. This work establishes quantitative mineralogical and chemical methodology that enables a more fundamental link between initial mold powder composition and thermophysical behavior.