REACTION-KINETICS OF CO2-H2O GAS-MIXTURES WITH LIQUID FE-C ALLOYS

The rate of decarburization of carbon-saturated liquid iron with CO2-H 2O gas mixtures has been studied to better understand the reaction mec hanism between liquid iron containing carbon with post-combusted gas i n an iron bath smelting reactor. The measurements were done under cond itions in which the effect of mass transfer is negligible. The experim ental temperature was 1 773 K and the sulfur content in the metal was fixed at 0.2 mass%. The rate was measured for a partial pressure of CO 2 in the range of 0.5 to 1 atm for CO2-Ar, 0.7 to 0.9 atm for CO2-H2O and 0 to 0.95 atm for CO2-5%H2O-Ar gas mixtures. The measured rates ag reed well with the predicted rates by assuming an ideal additivity of CO2 and H2O reaction rates individually measured in previous work. It was concluded that there were no special effects retarding or accelera ting the reaction rate with liquid iron and the rates were simply addi tive. It was also found that iron oxide did not form on the surface as long as the surface concentration of carbon did not become very low. The critical carbon content at which FeO forms on the surface was expr essed as a function of partial pressure of oxidant, sulfur content in the metal, mass transfer coefficient and temperature and was found to be in agreement with experimental observations.