Activity of VO1.5 in CaO-SiO2-MgO-Al2O3 Slags at Low Vanadium Contents and Low Oxygen Pressures
2009 (English)In: Steel Research International, ISSN 1611-3683, Vol. 80, no 4, 251-255 p.Article in journal (Refereed) Published
In the present work, the gas-slag equilibration technique was employed for the measurement of the thermodynamic activity of vanadium oxide. The vanadium-containing slag kept in a platinum crucible was equilibrated with a gas mixture of CO, CO2 and Ar, with well-defined oxygen partial pressure at a pre-determined temperature. The slag sample was quenched and the composition of the final slag was determined by chemical analysis. From the value of the oxygen partial pressure, the thermodynamic activity of VO1.5 could be calculated using the value for the activity of vanadium in V-Pt alloy. The measurements were carried out in the temperature range 1823 similar to 1923K and the oxygen partial pressures employed were 10(-3), 10(-4), 10(-5) Pa. The present results show that the activity of vanadium(III) oxide in slag exhibits a negative deviation from ideality in the present composition range. With increasing basicity of the slag, the final content of vanadium oxide in the slag was found to show an initial increase followed by a constant content. The activities of vanadium(III) oxide did not exhibit any significant change with increasing temperature. The activity coefficient of vanadium(III) oxide decreased sharply with slag basicity approximately up to a basicity of 1, beyond which it showed a near-constant value. Increase in basicity was found to cause a change in the distribution of vanadium between the slag and the alloy phases even though this effect was less pronounced. From the present results, a mathematical relationship for estimating the vanadium content in slag for a given activity of vanadium in the molten metal phase was developed.
Place, publisher, year, edition, pages
2009. Vol. 80, no 4, 251-255 p.
equilibrium, activity, vanadium oxide, steel, melts, liquid-iron, melts, chromium
Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:kth:diva-18382DOI: 10.2374/sri08sp138ISI: 000265746700001ScopusID: 2-s2.0-67249117794OAI: oai:DiVA.org:kth-18382DiVA: diva2:336428
QC 201005252010-08-052010-08-052010-10-14Bibliographically approved