Abstract

CaO and CaF₂ are important slag constituents and additive materials in secondary metallurgy. Optimization of the quantity of these compounds has a key role in adjusting the slag chemistry for optimal refining properties. In this study, the CaO and CaF₂ content of the slag has been analyzed with optical emissions from an industrial ladle furnace measured through the casting spout. Molecular optical emissions from CaO and CaF were observed directly from the molten bath and the arc, whereas atomic emission lines from the slag components were detected in the arc spectra. Optical emissions from CaO, CaF, and atomic calcium lines have been correlated with the CaO and CaF₂ content of the slag. The CaO and CaF₂ content of the slag could be evaluated from the spectra ranging from 10 to 41 min before the X-ray fluorescence (XRF) analysis was finished. The mean differences between the OES and XRF analysis were 0.59 % and 0.61 % for CaF₂, and 2.19 % and 0.67 % for CaO when using the spectra from the molten bath and the arc, respectively. The method has the potential to work as an in situ online measurement system due to real-time data acquisition and fast computation times.