Corrosion mechanism of MgO-C bricks used as linings in a vanadium extraction converter

To extend the service life of MgO-C bricks used as linings in vanadium extraction converters, their corrosion mechanism was investigated using stationary immersion and rotary crucible methods at 1673 K. The effects of oxides in vanadium slag were studied using the slag invasion method. The results showed that a decarburization layer was formed but was not effectively sintered under vanadium extraction conditions, resulting in it having a loose structure and poor binding strength. When slag-splashing technology was applied to protect the converter, the decarburization layer and slag-splashing layer easily fell off due to scouring by the molten pool. Consequently, the poor strength of the decarburization layer was the main reason for the poor anti-erosion performance of the MgO-C bricks and the weak effect of slag-splashing technology. In addition, higher contents of SiO₂ and TiO₂ in vanadium slag could form low melting point compounds and increase the thickness of the decarburization layer, thereby accelerating the MgO-C brick corrosion rate. Higher contents of FeO in the vanadium slag not only formed low melting point compounds but also caused a decarburization reaction with the MgO-C bricks. However, with increases of V₂O₃ in the slag, the formation of high melting point compounds decreased the corrosion rate and corrosion depths.