<Original Papers>On the Relation among Silicium, Carbon in the Molten Iron and CO-CO_2 Mixed Gas

In the previous report, the authors have proposed the following equation as the equilibrium relation of this system : [chemical formula] [chemical formula] and proposed the following equation in the range, 1,500～1,600℃ and 0.4～1% CO_2 in CO-CO_2 mixed gas under the condition of being saturated with SiO_2 : [chemical formula] [chemical formula] Maximum concentration of Si and C in the molten iron were about 4% and 0.9% respectively in this measurement and the solution obeyed Henry\u27s law approximately. But deviations from Henry\u27s law were expected at higher concentrations of these elements than the above. In order to ascertain these points, measurements were carried of out in the range, 1,450～1,500℃ and below 0.3% CO_2 in CO-CO_2 mixed gas. Thus, the authors ascertained that the activity coefficient of C in the molten iron increased but that of Si was constant, corresponding to the increase of these elements. Further, the temperature function of the equilibrium constant was respectively as follows : [chemical formula] [chemical formula