Investigation of CaO/Al2O3 Mass Ratio on the Properties and Structure of Ce2O3-Containing CaO-Al2O3-based Tundish Flux

The properties and structure of Ce2O3-containing CaO-Al2O3-based tundish flux with different w(CaO)/w(Al2O3) have been investigated by hemispherical melting point method, the rotating cylinder method, and Raman spectroscopy, respectively. Results suggested that the melting temperature decreased from 1 340 degrees C to 1 309 degrees C, softening temperature from 1 337 degrees C to 1 304 degrees C, while the fluidity temperature changed not profound as the w(CaO)/w(Al2O3) from 0.9 to 1.3. The melting properties remained relatively steady when w(CaO)/w(Al2O3) was above 1.1. An increase in the w(CaO)/w(Al2O3) led to a decrease in viscosity, breaking temperature, and activation energy. A good property of the slag with w(CaO)/w(Al2O3) ranged from 1.1-1.3 in the current work. The main structural units of the AlO4-tetrahedral were Q(A)(l)(2), Q(A)(l)(3), and Q(A)(l)(4), while the major structural units of SiO4-tetrahedral were Q(Si)(0), Q(Si)(1), in the current system. With the increasing w(CaO)/w(Al2O3), the polymerized units Q(A)(l)(3), and Q(Al)(4), were modified to Q(Al)(2), in aluminate structure. In silicate structure, the Q(Si)(1) unit was modified to Q(Si)(0) with the increasing w(CaO)/w(Al2O3). CaO could exert a stronger ability to stabilize the AlO4-tetrahedral unit in the current melts. Meanwhile, the increase of NBO/T and Lambda(corr) indicated the decrease of DOP in the melt.