Kinetics of the reaction of C2H6, CH4-CO2 and CO-CO2-O-2 gases with liquidiron

The kinetics of several gas-metal reactions relevant to bath smelting have been investigated. The rate of carburization of liguid iron by C2H6 gas was measured between 1 400 and 1 600 degrees C under conditions in which parti al pressure of C2H6 was in the range of 0.016 to 0.04 atm and sulfur conten t in the iron was in the range of 0.003 to 0.5 wt%. The experimental result s indicate that the rate is controlled by the dissociation of C2H6 on the s urface of iron and gas phase mass transfer in Series. The gas phase mass tr ansfer can be corrected with reasonable accuracy and the chemical rate cons tants were obtained. The rate was retarded by sulfur in liquid iron and the re was evidence of a large residual rate at high sulfur contents. The rate of carburization of pure liquid iron (a(s)=0.01) by CH4-CO2 gas mixture was measured at 1 600 degrees C under conditions at which the rate is controll ed by gas phase mass transfer and chemical reaction in series. The gas was 6% CH4 and up to 2.5 % CO2 in Ar. It was concluded that CH4 and CO2 reached the surface of the iron before they reacted with each other and carburizat ion by CH4 and decarburization by CO2 occurred independently for the presen t experimental conditions. The rate of decarburization of carbon saturated liquid iron by CO-CO2-O-2 gas mixture was measured at 1 600 degrees C. The partial pressure of O-2 in 90%CO/10%CO2 gas was in the range of 0 to 0.03 a tm and sulfur content in the metal was 0.1 wt%. The measured rate shows tha t the gases reached the surface of metal before they reacted with each othe r and decarburization by CO2 and O-2 proceeded independently at a high gas flow rate (5 l/min), but there may have been some gas phase reaction at low er flow rate (2 l/min).