Interfacial reaction between CO2-CO gas and molten iron oxide containing P2O5

Abstract

The interfacial reaction between CO2-CO gas and molten iron oxide containing P2O5 was investigated by the 13CO2-CO isotope exchange technique at 1773 K with CO2/CO=1.0. The apparent rate constant rapidly decreased with the addition of P2O5 up to 2.86 mol pct PO2.5 and the Fe3+/Fe2+ ratio kept constant at approximately 0.2. By the classic site blockage model, in which the reaction only occurs on the vacant sites, and the modified site blockage model, in which the reaction occurs on the vacant sites and the sites occupied by phosphorus simultaneously, the effect of the addition of P2O5 was analyzed and the reaction mechanism of CO2 dissociation was discussed. It may be concluded that the dissociation of the adsorbed CO2 molecule is reasonable as a rate-determining step and that the effect of phosphorus on the interfacial reaction is caused by the decrease in the number of active sites with the increase of phosphorus content as a surface active element in molten iron oxide.