Oxidation of Fe-V Melts Under CO2-O-2 Gas Mixtures
2010 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 41, no 5, 1042-1051 p.Article in journal (Refereed) Published
The oxidation mechanism of liquid Fe-V alloys with V content from 5 to 20 mass pct under different oxygen partial pressures using CO2-O-2 mixtures with CO2 varying from 80 pct to 100 pct was investigated by thermogravimetric analysis between 1823 K and 1923 K (1550 degrees C and 1650 degrees C). The products after oxidation were identified by scanning electron microscopy energy-dispersive spectrograph and X-ray diffraction. The results indicate that the oxidation process can be divided into the following steps: an apparent incubation period, followed by a chemical reaction step with a transition step before the reaction, and diffusion as the last stage. At the initial stage, a period of slow mass increase was observed that could be attributed to possible oxygen dissolution in the liquid iron-vanadium coupled with the vaporization of V2O. The length of this period increased with increasing temperature as well as vanadium content in the melt and decreased with increasing oxygen partial pressure of the oxidant gas. This analysis was followed by a region of chemical oxidation. The oxidation rate increased with the increase of the O-2 ratio in the CO2-O-2 gas mixtures. During the final stage, the oxidation seemed to proceed with the diffusion of oxygen through the product layer to the reaction front. The Arrhenius activation energies for chemical reaction and diffusion were calculated, and kinetic equations for various steps were setup to describe the experimental results. The transition from one reaction mechanism to the next was described mathematically as mixed-control equations. Thus, uniform kinetic equations have been setup that could simulate the experimental results with good precision.
Place, publisher, year, edition, pages
2010. Vol. 41, no 5, 1042-1051 p.
liquid-iron, vanadium, equilibrium, spinels, oxygen, slags
Metallurgy and Metallic Materials Materials Engineering
IdentifiersURN: urn:nbn:se:kth:diva-27945DOI: 10.1007/s11663-010-9391-3ISI: 000284333700014OAI: oai:DiVA.org:kth-27945DiVA: diva2:383235
QC 201101042011-01-042011-01-032014-06-13Bibliographically approved