Abstract
In order to reveal the kinetic behavior of the anodic reaction between FeO-CaO-SiO2(-P2O5) slags and solid iron, the interfacial impedance was measured by using AC impedance method, and factors on kinetics of the electrode reaction such as Warburg parameter and charge transfer resistance were determined.
The measurements were made in the frequency range from 0.01 Hz to 20 kHz at 1623K under an argon gas atmosphere by applying 60 mV DC potential between a working electrode and a counter electrode of iron crucible.
The Warburg parameter and the charge transfer resistance were of the order 10-7Ω m2 s-1/2 and 10-710-8 Ω m2, respectively. Both of them decreased with the increase of the CaO content in slag when the FeO content was constant and decreased with the addition of P2O5 to slag. This result shows that the mass transfer behaves as a rate-control step in the dissolution reaction of iron into FeO-CaO-SiO2(-P2O5) slag, as the charge transfer resistance is rather small.
