The experimental procedure to reduce contamination of the slag by reaction with crucible in a rotating crucible furnace has been described.
The distribution of oxygen between molten iron and lime-iron oxide slags has been determined and used to calculated activities of Fe_tO, CaO in the system.
The solubility of oxygen in a molten iron at 1560°C under pure iron oxide slag or lime saturatediron oxide slag conforms to the results of other investigators.
When the lime content is less than 0.23 mole fraction, the activity of iron oxide, which is defined as the ratio of the observed oxygen content of the metal to that under pure iron oxide slag, deviates slightly positive from Raoult's law.
In the range of lime content more than 0.23 mole fraction, it reveals negative deviation, which is increased with lime content. Iron oxide activity in the lime saturated iron oxide slag is 0.45 at 1560°C.
It has been determined that α-function for Fe_tO defined as logγFe_tO/(1-NFe_to) ² is a linear func-tion of lime content, that is, αFe_to=1.0-4.3 NCao.
Taking the components of the system as Fe_tO, CaO, the activity of lime has been calculated from the Gibbs-Duhem equation.