Kinetic Studies on Evaporation of Liquid Vanadium Oxide, VO _x (Where x = 4 or 5)

As part of the Swedish National Eco-steel project, the present work was carried out with a view to study the evaporation of vanadium as V₂O₅ with a focus on the health hazards. The evaporation rate was followed by monitoring the mass loss from liquid V₂O₅ melts by thermogravimetric analysis (TGA) in the temperature range 1723 K to 1873 K (1450 °C to 1600 °C). The studies were carried out under three different oxygen partial pressures, viz, oxygen, air, or CO₂. The experiments were carried out in the isothermal mode. The Arrhenius activation energies for the evaporation reaction in different atmospheres were calculated from the results. A mathematical model was developed in order to describe the kinetics of the evaporation process. Good agreement could be achieved between the mathematical model and the experimental results. Evaporation coefficients and enthalpies in different atmospheres were also estimated. The present results may also have implications in recovering vanadium values from different vanadium sources.