P. Korgul et al., MICROSTRUCTURAL ANALYSIS OF CORRODED ALUMINA-SPINEL CASTABLE REFRACTORIES, Journal of the European Ceramic Society, 17(1), 1997, pp. 77-84
Microstructural analysis indicates that the corrosion of alumina-spine
l castables by a liquid steel ladle slag involves initial reaction of
CaO in the slag with alumina fines in the refractory bond. The slag be
comes saturated in CaO and Al2O3 and CA(2) is precipitated from it alo
ng with other calcium aluminates. The spinel fines and grains in the r
efractory take up the MnO/FeO/Fe2O3 from the slag, which becomes silic
a-rich as CA(2) is precipitated and highly viscous. The thickness of t
he remnant slag layer on the corroded samples indicates the viscosity
of the liquid slag under the test conditions. Further into the refract
ory CA(6) is formed, firstly crystallized with a tabular morphology in
dense regions and then with a similar morphology in more porous regio
ns. Deeper still in the refractory CA(6) takes a whisker/needle habit
suggesting some vapour-phase reaction. MgO-rich spinel-alumina castabl
es undergo less corrosion under these conditions as dissolution of MgO
leads to a viscous MgO-rich slag which is less corrosive to the Al2O3
components of the refractory. (C) 1996 Elsevier Science Limited.