Effect of P2O5 addition on the rate of CO2 dissociation on the surface of FetO-base molten oxides

For clarification of the surface active effect of P2O5 in the reaction kinetics and mechanism of the various metallurgical processes, the effect of P2O5 addition on the reaction rate of CO2 dissociation on the surface of the FetO, FetO-CaO (mol%FetO:mol%CaO=6:4), FetO-SiO2 (mol%FetO:mol%SiO2=7:3), and FetOCaO-SiO2 (mol%FetO=35, mol%CaO/mol%SiO2=1.13-1.27 and 1.36-1.47) melts was investigated at 1773 K with P-CO2/P-CO=1 by using isotope exchange technique. The rate constant decreased with increasing P2O5 content of melts and the residual rate constant was observed at high P2O5 content. However, the change of the Fe3+/Fe2+ ratio of molten oxide was not observed. Results were analyzed by using site blockage model of P2O5 and it was concluded that the rate controlling step of CO2 dissociation was the dissociation reaction of adsorbed CO2 molecule on the surface of molten oxides.