Post-mortem analysis of high alumina brick attacked by vanadium and titanium bearing slag after service in torpedo ladle

摘要

High alumina brick after service in a torpedo ladle was analysed by means of atomic emission spectroscopy, X-ray diffraction, electron probe microanalysis and thermochemical analysis in order to determine the corrosion mechanism during industrial application in a steel works. The results showed that slag containing vanadium and titanium oxide is more corrosive than common silica slags, and that this facilitates corrosion and penetration into the high alumina brick. Mineralogical observation confirmed that V_2O_5, TiO_2, MnO and FeO and MgO in the slag reacted with native phases presented in high alumina brick to form complex spinel, corundum and anorthite solid solution, etc. The dissolved content of V_2O_5 in the spinel decreased from 6.08 to 2.78 wt-% from the working face to the inner area. However, the FeO and MnO content in the spinel varied little with a slight increase in the TiO_2 content. The expansion coefficient mismatch between the penetrated zone and cold face zones, which results in densification spalling and increased porosity, play a key role in the failure of the high alumina brick.