Structure and viscosity of slags containing cerium oxide

Abstract

The effect of cerium oxide on the viscosity and crystallization temperature of slags of the CaO–SiO₂–Ce₂O₃–Al₂O₃–MgO oxide system is studied using an electrovibrational viscometer. The structural characteristics of hardened slag samples are studied using a Raman microscope-spectrometer. The results demonstrate that the viscosity and crystallization temperature of the slags are considerably reduced upon adding cerium oxide. An increase in content of Ce₂O₃ from 0% to 15% facilitates decrease in slag viscosity from 0.4 to 0.2 Pa ∙ s at 1500 °C and reduction in crystallization temperature from 1485 °C to 1397 °C. The structural analysis results reveal that the main form of polymerization of the [SiO₄]-tetrahedra in the silicate regions are the structural units ${Q}_{\mathrm{Si}}^{0}$, ${Q}_{\mathrm{Si}}^{1}$, and ${Q}_{\mathrm{Si}}^{2}$ for the slags with 0%, 5%, and 10% Ce₂O₃, respectively, except for the slag with 15% Ce₂O₃, for which we noted only 2 units ${Q}_{\mathrm{Si}}^{0}$ and ${Q}_{\mathrm{Si}}^{1}$, which shows structural simplification. A second characteristic peak appears with increase in content of cerium oxide, corresponding to the [AlO₆]-octahedral unit, which also indicates structure simplification. The degree of melt polymerization decreases from 0.83 to 0.52 with increase in content of cerium oxide, which explains the decrease in viscosity and crystallization temperature. Cerium oxide is used as a structure modifier to reduce the slag viscosity.