Oxygen Exchange Reaction between CO2-CO Gas and Molten Oxide Containing Iron Oxide

Abstract

Oxygen exchange reaction rates between CO 2 -CO gas and molten oxides containing iron oxide have been measured by isotope exchange technique with 18 O at 1 773 K with P CO 2 /P CO ϭ1. Measured results represent that the oxygen exchange reaction rates show the maximum values at the beginning of the reaction and sharply decrease within approximately 20 s, and then gradually decrease with the reaction time proceeds. These changes indicate that the rate-limiting step would change from the dissociative adsorption of oxygen on the surface of molten oxide in the initial stage of reaction to the mass transfer of oxide ion from the surface to the inside of molten oxide in the following stage. Based on the kinetic analysis of the oxygen exchange process, CO 2 dissociation rate constant, CO 2 re-formation rate constant and the mass transfer coefficient of oxide ion in molten oxides were calculated for the FeO x -CaO and FeO x -SiO 2 systems. Addition of CaO and SiO 2 to molten oxide increases and decreases the oxygen exchange reaction rate, respectively.

Interfacial Rate of CO2^|^ndash;CO Reaction with the Solid Iron and Iron Oxide by Isotope Exchange Technique at 1273 K

“…From the 1960s, the isotope exchange technique, as an effective experimental method to study the interfacial kinetics between gas and iron oxide, has been extensively used by many researchers in metallurgical field. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Recently, in order to meet the strong demand on the utilization of low grade iron ores and reduction of CO2 emission, the direct reduction of fine iron ore, as an innovative ironmaking process, has been given more attention. Therefore, the kinetics of CO2-CO reaction with the solid iron oxide became more important.…”