Improved Quasi-regular Solution Model In Binary Metallurgical Slag System

In this thesis, based on the experiment values of activity in binary molten slag reported in published literature, the activity of every component in eight binary molten slag systems were validated. The total average error of two components is 2.6% and 2.5% separately that was got. And the reliability of experiment dates has been evaluated. The relative error of every component in B2O3-SiO2 (1-2) system is S1*(1723K)=7.3%, S2*(1723K)=7.4% and S1*(1823K)=14%,S2* (1823K)=12%. The relative error of every component in other seven systems is below 6%. Therefore by the validation of Gibbs-Duhem equation, the experiment dates in other seven binary molten slag systems except B2O3-SiO2 at different temperature is reliable. The infinitesimal activity coefficient is one of the most important thermodynamic parament, so the infinitesimal activity coefficient of every component is calculated in this thesis.Seven binary molten slag systems in the whole concentration and twelve binary molten slag systems existing saturation concentration are calculated by the application of regular solution model, sub-regular solution model and quasi-regular solution model. For the systems in the whole concentration, the total average relative error of every component is 8.9% and 6.9% separately by the application of regular solution model,3.2% and 4.1% separately by the application of sub-regular solution model and 7.4% and 7.7 separately by the application of quasi-regular solution model. For the system existing saturation concentration the total average relative error of every component is 48% and 3461% separately by the application of regular solution model,16% and 1088% separately by the application of sub-regular solution model and 48% and 1089% separately by the application of quasi-regular solution model. Modified quasi-regular solution model has been got based on sub-regular solution model and quasi-regular solution model. The parameter of regular solution model Q can be denoted a function of concentration and temperature. The three parameters of the model are fitted by the experiment dates of activity in two temperatures. The binary molten slag systems have been calculated by the application of the model. For the seven molten slag systems in the whole concentration, the total average relative error is 3.2% and 4.0% separately. And for the ten binary molten slag systems existing saturation concentration, the total average relative error is 19% and 1015%. By the comparer of calculated result by the application of regular solution model, sub-regular solution model, quasi-regular solution model and modified quasi-regular solution model, The modified quasi-regular solution model is a little superior than the sub-regular solution model, the sub-regular solution model is superior than quasi-regular solution model and the three models are much superior than regular solution model.Further more, one ternary molten slag system of FeO-Fe2O3-SiO2 and two quarter molten slag systems of FeO-Fe2O3-SiO2-CaO and FeO-Fe2O3-SiO2-NiO are fitted. Eight pairs of international energy have been got and the activity of FetO is calculated. The average relative error of calculated dates and experiment dates in FeO-Fe2O3-SiO2 system is 3.9%. That is to say, the results calculated are agreement with experiment dates. The average relative error of calculated dates and experiment dates in FeO-Fe2O3-SiO2 system is 18%. That is to say, the results calculated are approaching experiment dates. Because there are not the experiment dates of activity of FetO in FeO-Fe2O3-SiO2-NiO, the result of comparer of activity can not been got.