Kinetic Model for the Reaction between Iron Oxide in Molten Slag and Carbon in Molten Iron via CO-CO₂ Bubble

Abstract

The kinetic model for the reaction between iron oxide in molten slag and carbon in molten iron was developed, assuming CO and CO₂ in the bubble on slag/metal interface was a ferrying medium for oxygen. The overall reaction was combination of two reactions : reduction of FeO by CO and oxidation of the carbon by CO₂.
The slag/gas and gas/metal interfacial area were evaluated by calculating the shape of the bubbles and their occupying area on the slag/metal interface. The shape of the bubble was calculated assuming mechanical balance of surface and interfacial tensions and gravity. The bubble occupancy area was estimated by simulating the growth and detachment of the bubbles on slag/metal interface. The calculated results are that the ratio of the slag/gas interfacial area to gas/metal is greater than 5, and that gas/metal interfacial area is less than 30% of apparent slag/metal interface.
Assuming the rate limiting step is either of the interfacial reactions, the overall reaction rate was calculated. The calculated rate is slower than published experimental data, as far as using GRAENZDOERFFER et al.'s equation and Sain-Belton's equation for the interfacial reaction rates. It suggests that the two stage reaction mechanism could not be adequate one within this model.