The Conductivity and the Crystallization of Perovskite (CaTiO_3) from Ti-bearing Blast Furnace Slag Studied by A.C. Impedance Method

摘要

The conductivities of a Ti-bearing blast furnace slag (with 23 TiO_2) and the synthetic slag consisting of CaO-SiO_2-Al_2O_3_TiO_2-MgO were measured accurately in the temperature range of 1653-1733K by A. C. impedance method. The relationships between the conductivity and temperature were obtained as: Ink = 14.212 - 24820/T for the Ti-bearing blast furnace slag and Ink = 8.557 - 1586/T for the synthetic slag (unit of k:Ω ~(-1).cm~(-1) in the temperature range of 1703-1733K. Perovskite phase (CatiO_3) could precipitate from these slags during slag cooling process. The temperature at which CatiO_3 started to crystallize was determined a s1693 K. Rate constants and activation energy for the formation reaction of CatiO_3 were calculated based on the data of conductivity and the first order kinetic equation. Dissociation reactions of the Al_2O_3 and TiO_2 could take place due to the crystallization of perovskite phase and the variation of the basicity of the basicity of the slag. The rate constants and the activation energy for the dissociation reactions were also calculated.