Effect of Ce2O3 and CaF2 on viscosity and structure of CaO-SiO2-CaF2-Ce2O3 slag

The influence of the growth of rare earth on the viscosity during the uniform cooling of CaO-SiO2-CaF2-Ce2O3 slag was investigated by the high temperature viscometer. The results show that Ce2O3 affects the viscosity variedly before and after the break temperature. At higher temperatures Ce2O3 reduces the viscosity. When the temperature is below the break temperature, at a Ce2O3 content of ≥3 mol%, a rare-earth crystalline phase is observed during the slag cooling process, and the break temperature progressively increases with the increase of Ce2O3 concentration. There are no crystallized rare earths in the slag under the condition of Ce2O3 concentration lower than 3 mol%. Too low or too high CaF2 content is found to be unfavorable for rare-earth crystallisation. The increase of Ce2O3 content facilitates the depolymerization of silica-oxygen tetrahedral structure. Ca‒F bond exists between structural units, weakening the flow resistance of structural units and lowering the viscosity of slag.