Effect of the colloidal zirconia on corrosion resistance of low-cemented alumina mixes against steel slag

Abstract

The corrosion resistance of the low-cement alumina base refractory against the slag of the electric arc furnace using zirconia was studied. Colloidal zirconia was replaced at the expense of the calcium aluminate cement by 1, 2, and 4 wt.% (C1, C2, and C4). The Andreasen coefficient of q = 0.23 was used to provide a reference sample with the 5 wt.% of the cement. The corrosion tests at 1620°C for 2 h were done and penetration zones were analyzed. In the case of samples prepared by colloidal zirconia, the penetration zone was enlarged due to the created porosity. The corrosion resistance of the C2 sample was improved. The new-formed calcium aluminate phase acts as a protective layer in the C2 sample. In the case of the C4 sample, the weight percentage of the calcium aluminate phase was significantly reduced. This can be related to the concentration gradient of calcium oxide in the slag and the matrix composition. However, the existence of the zircon phase in the C4 sample showed that the zirconia can react with the SiO2, leads to a lower temperature phase, and improve the corrosion resistance.

Keywords

• colloidal zirconia
• corrosion resistance
• alumina mixes
• microstructure