Interfacial kinetics of hydrogen with liquid slag containing iron oxide

Interfacial kinetics on the hydrogen reduction of liquid Fe _t O in Fe _t O-M _x O _y slag (M _x O _y = CaO, SiO₂, Al₂O₃, and TiO₂) has been studied at 1673 K. Because the rate of hydrogen reduction was very fast, the rate was controlled by gas-phase mass transfer under most of the experimental conditions. The effect of CaO or SiO₂ addition on the interfacial chemical reaction rate of hydrogen reduction was empirically evaluated as a function of the ferrous-ferric ratio in the slag. The observed interfacial chemical reaction rates in Fe _t O-CaO and Fe _t O-SiO₂ slags showed reasonable agreement with the estimated values. Most of the available literature data on the reduction rate of liquid iron oxide by solid carbon, hot metal, and reducing gases were also reviewed and compared with the results of the present work. It was found that the rate of hydrogen reduction of liquid iron oxide slag is much faster than that with other reducing agents such as solid carbon, carbon dissolved in the liquid iron, and CO gas. This article is based on a presentation made in the “Geoffrey Belton Memorial Symposium,” held in January 2000, in Sydney, Australia, under the joint sponsorship of ISS and TMS.