1999 Volume 39 Issue 11 Pages 1116-1119
The conductivities of a Ti-bearing blast furnace slag (with 23 % TiO2) and the synthetic slag consisting of CaO-SiO2-Al2O3-TiO2-MgO were measured accurately in the temperature range of 1 653-1 733 K by A. C. impedance method. The relationships between the conductivity and temperature were obtained as: lnκ=14.212-24 820/T for the Ti-bearing blast furnace slag and lnκ=8.557-15 860/T for the synthetic slag(unit of κ: Ω-1·cm-1) in the temperature range of 1 703-1 733 K. Perovskite phase (CaTiO3) could precipitate from these slags during slag cooling process. The temperature at which CaTiO3 started to crystallize was determined as 1 693 K. Rate constants and activation energy for the formation reaction of CaTiO3 were calculated based on the data of conductivity and the first order kinetic equation. Dissociation reactions of Al2O3 and TiO2 could take place due to the crystallization of perovskite phase and the variation of the basicity of the slag. The rate constants and the activation energy for the dissociation reactions were also calculated.