Interaction between magnesia and graphite bricks in furnace producing vanadium nitride

Abstract

A cavity between magnesia bricks and graphite slabs was found in a commercial furnace produced vanadium nitride after a 13 months campaign. The magnesia, zirconia–corundum–mullite and hollow sphere Al₂O₃ bricks taken from the dismantled furnace were investigated by chemical analysis, XRD and SEM. It was found that the compositions of magnesia bricks, which contact with graphite slabs, were almost not changed but the thickness of remaining bricks was far lower than that of the original ones. Spinel was detected in used zirconia–corundum–mullite bricks and hollow sphere Al₂O₃ bricks, which were above MgO bricks. A mechanism of cavity formation was proposed. This result may be a new evidence of reaction mechanism between magnesia and graphite via gas phase.

Keywords:

• REACTION MECHANISM
• THERMODYNAMIC
• MAGNESIA BRICKS
• GRAPHITE SLABS
• GAS PHASE REACTION