Dissolution Behavior of Al₂O₃ in Refining Slags Containing Ce₂O₃

Abstract

The effects of rotating speed, temperature and slag composition on the dissolution rate of alumina rod in molten CaO–SiO₂–Al₂O₃–MgO and CaO–SiO₂–Al₂O₃–MgO–Ce₂O₃ slag were investigated by the rotating cylinder method in the temperature range of 1793 K to 1853 K. It was indicated that faster rotating speed and higher temperature would result in an increasing of dissolution rate of alumina. The concentration profiles of Al, Ca, Ce etc. in the boundary layer as well as slag were determined by EDS analysis. Based on these results, the mechanism of dissolution of Al₂O₃ rod in Ce₂O₃ containing slag was discussed, and the apparent activation energy in the dissolving process were obtained in the range of 233–418 kJ/mol. The addition of Ce₂O₃ initially increased the dissolution rate of Al₂O₃, while hindered afterwards, which is explained from the view point of mass transfer coefficient.