Al_(2)O_(3)-MgO계 캐스터블 내화물의 내침식성 향상 = Improvement of the corrosion resistance in Al_(2)O_(3)-MgO castables

다국어 초록 (Multilingual Abstract)

To improve the mechanical and chemical properties of unfired Al_(2)O_(3) castables which is widely used in metal line of steel-making ladle, the ρ-Al_(2)O_(3) and /or fine MgO was added as a matrix powders and the degree of spinel formation was studied. Because the spinel was formed at the contact areas between Al_(2)O_(3) and MgO particles and the volume of in-situ formed spinel increased more abnormally at the site of Al_(2)O_(3) particles than MgO side, Al_(2)O_(3) aggregates was more recommendable than MgO aggregates. And to compare the degree of spinel formation in the Al_(2)O_(3)-MgO castable refractories, ultrafine SiO_(2) and Al_(2)O_(3) powders were added and their effects on physical properties such as permanent volume expansion and cold crushing strength were examined.
For ρ-Al_(2)O_(3) binder, it could be replaced the alumina cement so that the CaO content could be reduced, but low compressive strength and firing shrinkage inhibit it's application to castables. But MgO powders should be added and the finer the MgO powder, the better the residual expansion and in-situ Spinel formation was observed. And due to Spinel formation and dense microstructure, CA_(6) phase would not formed around alumina aggregates during corrosion so that the corrosion resistance was much more increased.