Effect of Li2O on melt crystallization of CaO-SiO2-CaF2 based glasses

This paper presents the effects of Li2O on the kinetics and structural aspects of the Cuspidine (Ca4Si2F2O7) crystallization behavior of CaO-SiO2-CaF2 glass (basicity 1.7). In order to elucidate the crystallization characteristics during differential scanning calorimetry (DSC) measurements, the kinetic parameters have been determined using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation. The crystallization rate constant and negative activation energy thus calculated indicated that the limiting step of crystallization was nucleation. Also, Raman spectroscopy and Solid-state MAS NMR spectroscopy analyses indicated that lithium could interact with fluorine, thereby disturbing the interaction between calcium and fluorine. This retards Cuspidine nucleation at the initial stage of melt crystallization. These findings on CaO-SiO2-CaF2-based glass lubricants can be used to optimize essential properties such as viscosity and crystallization temperature during continuous casting of steels.