Kinetics of the Reaction of CO2/CO Gas Mixtures with Iron Oxide

The kinetics of the oxygen exchange reaction between carbon dioxide and carbon monoxide were measured on iron, wüstite, and magnetite surfaces. This was done through the use of an isotope exchange technique. The measured rate constants are dependent on the oxygen activity. This dependence is expressed by ka = koaO−m. The parameter m was found to have values between 0 and 1. It was found that, in the iron region, the apparent rate constant was independent of the oxygen partial pressure (i.e., m = 0) at 1123 K (850 °C) and that it was inversely dependent on the oxygen partial pressure (i.e., m = 1) for the magnetite region at 1123 K (850 °C) and 1268 K (995 °C). In the wüstite region, m was found to be equal to 0.51, 0.66, and 1.0 for the w1, w2, and w3 pseudo phases, respectively, at 1268 K (995 °C). At 1123 K (850 °C), in wüstite, m was found to be equal to 0.59 and to 1.0 for the w1′ and w3′ pseudo phases, respectively.