Calculation And Plotting On Isothermal Section For FeO-CaO-TiO₂ Slag System

The phase diagram can denote the function relationship among the temperature, pressure force and the constitutes of the materials, which is used widely in the field of geology, physics, chemistry, chemical industry and metallurgy. It cost so much time and money to determinate a phase diagram by experiments, and this situation will be worse if there are more than one phase in the system. It is a good idea to get the phase diagram via calculating and doing experiments. The phase diagram of ternary system TiO2-CaO-FeO has not been reported. For the resource of titanium being made good use of , the study on this phase diagram is very important. The thermodynamics of the liquid phase is the core of the phase diagram. In this paper, the model of the thermodynamics was summed up and the characteristics and the suitable extension were concluded. Also , the action concentration of the The phase diagram of ternary system TiO2-CaO-FeO was be calculated by concurrent theory.A new method to calculate the isothermal section phase boundary was brought forward according to the relation among the activities of the quarter-phase boundary in the ternary system. And this paper calculated the isothermal section which has a interval of 100℃ from 1873K to 2273K of the ternary system TiO2-CaO-FeO. For the facility of the calculation, the isothermal section of the 1873K was been made as numeralization. The results of the calculation are as follows:(1) For the ternary system TiO2-CaO-FeO, according to the concurrent theory the possible structure cell was made certain, and the action concentration of the system was calculated.The isothermal section has five quarter-phase areas, three ternary phase areas and one liquid phase area. The isothermal section of 1973K has five quarter-phase areas, three ternary phase areas and one liquid phase. The isothermal section of 2073K has three quarter-phase areas and one liquid phase. The isothermal section of 2173K has two quarter-phase areas and one liquid phase. The isothermal section of 2273K has one quarter-phase area and one liquid phase.(3) the isothermal section of the 19872K was dealt according to numeralization. The program can distinguish which phase area the point of input is in, and can calculate the liquid phase quantity and solid phase quantity. The result of the calculation accords with the result from graphing method well.