| In this thesis, Based on Molecular Interaction Volume Model (MIVM) and its pseudo-multicomponent approach, activities of components,Activity coefficient and phase equilibrium law in manganese ferroalloy smelt proceed researching., In the meantime, a predicted model about thermodynamics properties, including activities of components, activity coefficient and phase equilibrium law etc,is predicted, providing the necessary theoretical foundation and enrich and improve the thermodynamic data.In the alloy system, activity of Mn in Mn-C-Si, Mn-Fe-C, Mn-Fe-C-Si melt is predicted by the MIVM with both unsimplify and simplify the model parameters and the Unified Interaction Parameter Formula (UIPF) Whose predicted values are compared with experimental data. The results show that predicted values of MIVM are agree with experimental data and are overall better than the predicted value of UIPF. In the Mn-Fe-C system, the relative error of predicted value of MIVM is 8%, the relative error of predicted value of UIPF are different because of applied to different investigators parameters and between 6-14%,the average error is 10%; in the Mn-C-Si system, the relative error of predicted value of MIVM and UIPF is 10% and 28% respectively. in the Mn-Fe-C-Si system, the relative error of predicted value of MIVM and UIPF is 5% and 12% separately at xFe=0.05, the relative error of predicted value of MIVM and UIPF is 8% and 11% respectively at xFe=0.1. The results indicate that MIVM has good predictive ability in terms of predicted activities, and that UIPF is possibly replaced by MIVM in some degree.In the oxide slag system, based on the MIVM and its pseudo-multicomponent approach with both unsimplify and simplify the model parameters, the thesis predicts activities of component main slag system in the manganese ferroalloy smelt including five ternary systems, such as CaO-MnO-SiO2, CaO-MnO-Al2O3 etc, and three quaternary systems(CaO-MnO-Al2O3-SiO2 etc). The results show that the predicted values of MIVM are agree with experimental data.The relative error of predicted value of MIVM respectively is:in the CaO-MnO-SiO2 system, MnO is respectively 20%,18%;FeO is even 14%;MnO is even 28% and FeO is 8%,14%, in the MnO-FeO-SiO2 system; MnO is 54% and 50%, in MnO-Al2O3-SiO2 system, although the relative error of predicted value of MIVM is leading big, deviation of MnO is 0.0709,0.0689; FeO is 22%,19%, MnO is 14%,15% in MnO-FeO-TiO2 system; FeO is 19%,10% and MnO is 37%,30% in MnO-FeO-Al2O3-SiO2 system; the relative error of MnO predicted by MIVM is 27%,29% compared with Abraham’s experimental data and is even 27% compared with Kor’s experimental data in CaO-MnO-MgO-SiO2 system; Activity coefficient of MnO is 26%、18% and Activity of MnO is 26%、18% at and Activity coefficient and Activity of MnO is 26%、18% and MnO is even 27% in CaO-MnO-Al2O3-SiO2 system. The results indicated that MIVM has strong ability to predict the thermodynamic properties of slag. In some systems, MIVM Parameters can be simplified based on the reality that simplified predictied values is more accuracy than the no simplified ones.In equilibrium prediction, this thesis research on the Mn reaction equilibrium distribution coefficient and thermodynamic properties at equilibrium concentration of Mn through the production of manganese ferroalloy major CaO-MnO-SiO2 ternary slag system predicted by MIVM pseudo-multicomponent study. The concentration equilibrium of Mn agree good with the experimental data, and the relative error of predicted value of concentration equilibrium of Mn is 38%.Also on the system of dualistic basicity of LMn distribution coefficient was studied, it is concluded that with the increase of binary basicity of slag, LMn increased. Therefore, in actual operation, increasing slag basicity is beneficial to improve the utilization and recovery rate of Mn, it also consistent with the actual operation. The results show that MIVM has good predictive ability in terms of phase equilibrium thermodynamic properties. |
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