The oxygen pressure of dilute Fe x O‐CaO‐Al 2 O 3 slag in equilibrium with liquid iron

The relationship between slag composition and oxygen partial pressure of dilute Fe x O‐CaO‐Al 2 O 3 slag in equilibrium with iron the activity of which is below 1 was extrapolated to give the oxygen partial pressure of a slag equilibrated with iron of the activity 1. In the process of extrapolation, the oxygen partial pressure and the activity of iron were unified to give a single thermodynamic quantity which is defined as: , where K ( x ) is the equilibrium constant for the formation reaction of Fe x O and is considered to be a function of x. The dependence of on the slag composition was obtained experimentally. On the other hand, it was found that the plot of against log a Fe has the slope −1 as expected from the theoretical consideration. The relation has been employed to estimate the composition of slag in equilibrium with liquid iron. Thus, the obtained composition is used to calculate the values of and of the slag in equilibrium with liquid iron.