Quantitative Characterization of Reaction Behavior between La‐Bearing FeCrAl Melt and CaO–SiO2‐Based Slags

Abstract

The reaction behavior between La‐bearing FeCrAl melt and CaO–SiO2‐based slags is quantitatively characterized based on industrial sampling, slag‐steel reaction simulation experiment, mass balance calculation, and thermodynamic theoretical analysis. In the results, it is shown that compared with FeCrAl melt, [La] in La‐bearing FeCrAl melt not only reacts with SiO2 in slags, but also promotes the reaction of [Al] with SiO2 and Na2O. The percentage of mass change of [La] after reaction with CaO–SiO2–Na2O–Al2O3 and CaO–SiO2–CaF2–Al2O3 slag is the highest increased by 92.43 wt%, and that of [Al] is the highest increased by 4.68 wt%. The percentages of mass change of SiO2, Na2O, and Al2O3 are the highest increased by 9.48, 2.91, and 52.86 wt%, respectively. Thermodynamic analysis shows that in FeCrAl melt, La not only increases the activity of itself, but also enhances the activity of Al to a certain extent, which is conducive to increasing the reaction degree between [Al] and Na2O and SiO2 in CaO–SiO2‐based slags. Moreover, the reaction behavior of CaO–SiO2–Na2O–Al2O3 and CaO–SiO2–CaF2–Al2O3 slags is compared and the main reasons are analyzed. The results of slag‐steel reaction simulation experiment are consistent with the trend of composition change of the mold flux in industrial sampling.