Effects of Li2O on crystallization of highly basic CaO-SiO2-CaF2 based mold fluxes

MasterMold flux has to retain low viscosity and adequate crystallization temperature to improve the quality of steel product during continuous casting. In this research, Effects of Li2O on crystallization behavior of CaO-SiO2-CaF2 based mold flux with basicity 1.7 have been investigated from kinetic and structural aspect. From iso-thermal crystallization kinetic analysis, it was revealed that all of samples have negative activation energy of crystallization which means crystallization is governed by nucleation. Also, it is observed that Li2O changes instantaneous nucleation to homogeneous nucleation and reduces crystallization temperature substantially. These results correspond with structural analysis which is done by Raman spectroscopy and Solid state MAS NMR spectroscopy, that Li cation is bound with F anion retarding crystallization of cuspidine crystal (Ca4Si2F2O7). In summary, addition of Li2O in highly basic mold flux is suitable for control of crystallization temperature and viscosity