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To understand the thermodynamic characteristics of the reaction between Al and SiO 2 during the continuous casting process of the high-aluminum steel, the activity coefficients of SiO 2 and MnO in molten slags of (18-43%) CaO-(33-64%) SiO 2 -(9-21%) Al 2 O 3 -(2-3%) MgO-( < 2.4%) MnO were measured at 1 400°C, 1 450°C and 1 500°C by the experiments of the Si and Mn equilibrium between liquid copper and molten slag in the graphite crucible under the mixed gas atmosphere of CO and Ar. The effects of SiO 2 , Al 2 O 3 , the basicity, the radio of CaO/Al 2 O 3 and the temperature on the activity coefficients of SiO 2 and MnO in molten slag were discussed. The quadratic regression relationships among the activity coefficient of SiO 2 or MnO, the concentration of component, the basicity and the temperature were investigated by the regression analysis method.

In order to study the effect of matrix metal species on the kinetics of the reaction of Si02 and MnO reduced by C in molten copper with carbon saturated, the experiment, in which a preliminary slag with the composition of 38%CaO-38%SiO2-20%Al2O3-2%MnO-2%MgO that was placed in a graphite crucible and reacted with pure metallic copper at 1450°C under the atmosphere of pure CO, was carried out. The kinetics of both the reactions of Si02 and MnO in molten slag reduced by C in molten copper with carbon-saturated (2[C]sat.in Cu + (SiO2) = 2CO(g) + [Si]in Cu and [C]sat.in Cu + (MnO) = CO(g) + [Mn]in Cu) have been studied by studying the changes of the concentration of Si and Mn in molten copper with carbon-saturated, and the reaction order and reaction rate constant of the two reactions have been obtained. The results show that: (1) The reaction of SiO2 reduced by C is 0.5th order reaction while it is -0.5th order reaction for MnO; (2) The reaction rate constant of the reduction of SiO2 reduced by C in molten copper with carbon-saturated is 7.50×l0−6 mass%0.5·s−1, while that of MnO reduced by C in molten copper with carbon-saturated is 5.52x10−6 mass%1.5·s−1; (3) In this study, the reactions of SiO2 and MnO reduced by C in molten copper with carbon-saturated is a slow reaction and the time for the reaction equilibrium is more than 22 hours.