Abstract Measurements of the rate constant of CO2 dissociation on the surface of molten FexO-SiO2-Al2O3-Cu2O slag have been made by using the 13CO2-CO isotope exchange technique as a function of temperature and imposed equilibrium CO2/CO ratio. It is shown that the apparent first-order rate constant remains fixed with Cu2O content from 1 to 10 wt% at higher oxygen potentials. The rate constant becomes approximately 2 times higher after metallic copper is reduced from the slag. The effect of temperature in the range from 1200 to 1450 °C on the rate constant was also studied and the activation energy was 190 kJ/mole for slag of composition 60FexO-30SiO2-10Al2O3. In the presence of Cu metal, the activation energy was reduced to122 kJ/mole.On a effectue des mesures de la constante de vitesse de dissociation du CO2 a la surface de scorie de FexO-SiO2-Al2O3-Cu2O fondue en utilisant la technique d’echange de l’isotope 13CO2-CO en fonction de la temperature et du rapport d’equilibre impose de CO2/CO. On montre qu...