Determination of the Rate of CO2-CO Reaction with Magnetite by Isotope Exchange Technique

To clarify the mechanism and get the accurate kinetic parameters of CO2CO reaction with magnetite, 13CO2CO isotope exchange technique was used to determine the rate constants of CO2 dissociation on the surface of magnetite from 1073 to 1373?K. The real interfacial rate constant was estimated by considering the gas phase mass transfer along a plate. The relationship of the rate constant and CO2/CO ratio was expressed by the formula of kc?=?k0 (CO2/CO)-1-m, m represents the effect of CO2/CO ratio on the activity of oxygen in iron oxide. The apparent activation energy of the reaction between CO2CO gas and magnetite was calculated to 161, 175?+-?15, 198, and 197?+-?16?kJ?mol-1 for CO2/CO ratios of 4.0, 5.0, 6.0, and 10.0, respectively. This dependence relationship may be caused by the decrease of free electron in magnetite phase with the increase of CO2/CO ratio.