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The improvement of industrial parameters like the basicity and sintering temperature and the selection of raw materials to form the acicular calcium ferrites become the hot topic in sintering production. However, the experimental with the sintering pot in the laboratory is still a main method up to now, no effective mathematical model or experience equations were developed. Factsage is a software for thermodynamic calculation in ironmaking and steelmaking. In present study, Factsage was used to calculate the liquid phases formulation during the sintering. The effect of the chemical compositions on the liquidus projection was also discussed. It was found that the content of liquid phase formed is about 25%-70% at 1 250°C due to their chemical composition. The more SiO2, the easier to form liquid phase. The experiments were carried out for the validation. It was found that the calculations of the mass of liquid phase generation cannot give a very good and accurate agreement with the measurement of the melting behavior of the sample quantificationally, however, for the ability of the liquid phase formation during the sintering, the calculations can give a good qualitative results, especially in the temperature of melting begin and the temperature of 50% shrinkage. The calculations reported in this study can be used to estimate the sintering behavior of the iron ores under a certain industrial condition to reduce the extra experiments. The experiments also shows that the calculations by Factsage can give some good explanations on the phenomenon of the melting behavior of different samples.

The effect of Fe-Si on the carbothermaic reduction of Panzhihua titanomagnetite concentrates were investigated under argon atmosphere by isothermal experiments at 1 623 K and non-isothermal experiments in the temperature range from room temperature to 1 723 K with a heating rate of 10 K/min, respectively. The morphology of reduced samples obtained by isothermal experiments was checked by scanning electron microscope. The results show that the addition of Fe-Si accelerates the carbothermic reduction rate of PTC. A part of silicon in the Fe-Si substitutes for carbon to participate the reduction of PTC. The addition of Fe-Si facilitates the nucleation and coalescence of metallic iron formed by reduction. A reaction mechanism for the carbothermic reduction of PTC with Fe-Si addition was proposed. The reduction process could be divided into three stages. In the first stage (lower than 1 273 K), the solid phase reactions with carbon and silicon as reductants are dominant. The exdothermic reduction by silicon, to a certain extent, promotes the reduction of PTC. In the second stage (1 273-1 423 K), the rate of reduction by CO is much faster than that of reduction by silicon, resulting in little influence of Fe-Si on the reduction of PTC. In the final stage, the reduction by silicon markedly occurs again, which further facilitates the coalescence of metallic iron and the reduction of PTC.