Abstract
In this study, a CaO–SiO2–Al2O3-based continuous casting mold flux was designed using the FactSage thermodynamics software to determine the composition range of CaF2. The viscosity characteristics of the mold flux were determined using a rotating viscometer. The results show that the constant temperature viscosity at 1300 °C decreases gradually as CaF2 content is increased from 3% to 11% in the CaO–SiO2–Al2O3-based slag. Viscosity is reduced from 0.854 to 0.241 Pa·s, viscous the flow activation energy is reduced from 157.74 to 114.34 kJ·mol−1, and the break temperature is reduced from 1280 to 1180 °C. Furthermore, when the CaF2 content is increased from 3% to 11%, the number of nonbridging fluorine bonds (Al–F structure and Si–F structure) in the melt increases to 287, the number of bridging fluorine bonds (Al–F–Al structure, Si–F–Si structure, and Si–F–Si structure) is only 17, and the network rupture of fluorine ions in the system is larger than the network formation. Consequently, both the degree of polymerization and viscosity are reduced.
Highlights
The main component of fluorite is CaF2, which is added as an auxiliary material in the steel continuous casting production to improve the lubrication and partial heat transfer between a crystallizer and a solidified shell [1,2]
The thermodynamic calculations showed that the CaF2 content should be controlled within the range ofFigure below12
(1) The thermodynamic calculations showed that the CaF
Summary
The main component of fluorite is CaF2 , which is added as an auxiliary material in the steel continuous casting production to improve the lubrication and partial heat transfer between a crystallizer and a solidified shell [1,2]. Gao et al [10] used Raman spectroscopy to determine the effect of fluorine on the structure of a CaO–SiO2 –Al2 O3 –Na2 O–CaF2 continuous casting mold flux and reported that the number of nonbridging oxygen ions in Si–O and Al–O tetrahedra increased and the degree of polymerization decreased. Wang et al [16] studied the crystallization behavior of protective slag in a CaO–SiO2 –Al2 O3 slag system in CaF2 and pointed out that after the mass fraction of CaF2 was increased to a specific amount, the fluorine ion was converted to a certain degree due to the network forming effect. A CaO–SiO2 –Al2 O3 -based mold flux was designed using the FactSage thermodynamics software to determine the composition range of CaF2. That we understand the microstructure of fluorine, we can use molecular dynamics to explore the microcosmic aspects of combinations of alternatives to fluorine that are composed of one or more elements
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