Study On Mass Action Concentration Of TiO₂ And Slag Viscosity For Ti-containing Slag

The percentage of TiO₂ in the titanium-vanidium-magenite located in Sichuan-Panxi in China is considerable high. TiO₂ has a significant influence on blast furnace smelting process. At reducing condition, high melting-point matter, such as a serial of low oxide containing Ti and TiC(3 140℃),TiN(2 930℃) as well as Ti(C,N), are produced. Physicochemical properties of slag could be modified by these matters. And special performance of slag containing Ti is related to thermodynamics property of TiO₂-activity. Therefore, it is necessary to study activity of TiO₂ and establish its thermodynamics model and compared calculated values with measured ones. Important support is provided for further study of various physicochemical properties slag containing Ti.By summarizing published activity of thermodynamic model, the paper concludes properties and application range of some thermodynamic models at present. For different thermodynamic calculation models, activity has different calculation methods. But the reports were few concerning thermodynamic calculation model of TiO₂-containing system, especially multicomponent slag system. Aiming at this problem, and according to the characteristics of coexistence theory , in which mass action concentration(N) is the concen -tration obeying mass active law, and can be widely applied to multicomponent slag system. Thermodynamic models are established with theory and practice meaning.FeO-MnO-TiO₂ system, CaO- SiO₂-TiO₂ system, CaO-Al2_O3-SiO₂-TiO₂ system as well as CaO-MgO-SiO₂-Al2_O3- TiO₂ system are regarded as research objects. According to coexistence theory, structural units are determined and mass action concentrations calculation model of every system are established. Corresponding calculation programs are written by means of programming language Matlab5.3, resolving non-linear equations. Calculated results are mass action concentrations. Main conclusions are as follows:(1) For FeO-MnO-TiO₂ system, according to coexistence theory, the mass action concentrations of the slag contents have been calculated after slag units are determined. And with these results, application program is formulated by means of programming language Visual Basic6.0 with visual surface. Iso-mass action concentrations of TiO₂ are plotted at 1 748.15K and 1 773.15K.(2) For CaO-SiO₂-TiO₂ system, mass action concentrations model and viscosity model are created. And application program is formulated by means of programming language Visual Basic6.0 with visual surface. Iso-mass action concentrations of TiO₂ are plotted at 1 773.15K and 1 673.15K.(3) For CaO-Al2_O3-SiO₂-TiO₂ system, mass action concentrations model and viscosity model are produced. Curve for mass action concentrations of TiO₂ with composition is plotted at 1 673.15K. With the increase of TiO₂ in slag, mass action concentrations increased.(4) For CaO-MgO-SiO₂-Al2_O3-TiO₂ slag system, mass action concentrations model are established. In terms of curve for mass action concentrations of TiO₂ in slag with composition calculated result is, which fits measured values, , predicted by Li Daozhao well. In conclusion, on the basis of analysis structure for ternary system to quinary system containing TiO₂, mass action concentrations model are established, according to coexistence theory. Comparing calculated values with measured data, the results present that coexistence theory could be applied to slag containing Ti.