Equilibrium between Dissolved Oxygen in Liquid Iron and H2-H2O Gas Mixtures

A number of experimental studies have been made on the equilibrium of the reaction between dissolved oxygen in liquid iron and H2-H2O gas mixtures by many investigators. However, certain discrepancies are still found among their results when several recent observations are compared with the earlier works by Fontana and Chipman and subsequently Dastur and Chipman which have been generally accepted. In order to ascertain the sources of these discrepancies, in the present work, a series of preliminary experiments were made on the effect of thermal diffusion and of the sampling methods for oxygen in liquid iron upon the equilibrium constant. Taking these observations into consideration, a careful study to determine the equilibrium constant has been carried out over a wide range of oxygen contents in the liquid iron. The experimental results are represented as follows: O+H2(g)=H2O(g) K1=PH2O⁄PH2·fO·[%O] logK1=7040⁄T−3.224 log fO=(−1750⁄T+0.76)·[%O] From the data obtained in the range of comparatively higher concentrations of oxygen by using an alumina crucible, the saturation values of oxygen in liquid iron in the presence of alumina were estimated approximately as follows: log[%O]Al2O3=−3560⁄T+1.19.