Kinetics of iron oxidation with CO2between 1300 and 1450 °C

Abstract

The paper describes measurements of the kinetics of iron oxidation in CO 2 -CO mixtures of various compositions in the temperature range of 1300 to 1450°C. The reaction product is solid wustite below and liquid iron saturated iron-oxygen melt above 1377°C, the incongruent melting temperature of iron saturated wustite. The experiments were carried out by measuring the weight increase during the oxidation of an iron specimen connected to a thermo-balance with a platinum wire. The specimen had the shape of a flat plate, and the oxidising gas flowed past this plate with a defined velocity. Among the experiments the flow velocities were varied. The rate law is linear in the beginning of the single experiment and later becomes parabolic. The linear law was interpreted as caused by two resistances connected in series: the transport of the oxidising gas through the adjacent gas boundary layer, and the phase boundary reaction at the oxide interface