MODELING AND EXPERIMENTAL-STUDY OF GASEOUS OXIDATION OF LIQUID-IRON ALLOYS

On the basis of the experimental results and thermodynamic and kinetic theories, a system reaction model was developed for liquid iron react ing with O-2/CO2/CO/N-2 gases. For verification of the model, laborato ry-scale experiments using a levitation melting technique were carried out on the kinetics of simultaneous oxidation of carbon, silicon, and manganese in a liquid metal droplet by oxygen and/or carbon dioxide i n nitrogen gas. Both reaction model predictions and experiments show t hat for medium- or high-carbon (1.64 and 3.38 pct carbon, respectively ) liquid iron, oxidation of silicon and manganese occurs at 1873 K onl y after cessation of the vigorous decarburization reaction, but that t hey proceed from the beginning in a low-carbon (0.4 pct carbon) run. T he oxidation of silicon was accompanied by oxidation of manganese beca use of the reduction of the activity of manganese oxide once an oxide formed on the surface of the metal droplet. In a low-temperature run ( <1633 K), the metal surface was covered by a solid or very viscous oxi de layer and the reaction proceeds far more slowly. The reaction model does not interpret reaction behavior at lower temperature because dif fusion in the oxide layer may be the rate-controlling step, and this m echanism has not been included in the model.