Post-Mortem Investigation of a Steel Ladle Repair Mix Containing Porous Calcium Magnesium Aluminate Aggregates
As repair method for ladle walls shotcreting or casting are often chosen for big re-lining jobs. However, dry-gunning remains one of the most flexible and efficient repair method when smaller repairs are required. For all types of repair methods, beside the corrosion resistance of the material itself, also the bonding between the newly installed repair material and the remains of the previously used monolithic material is crucial for the total performance of the monolithic lining and its cost efficiency. While thick slag layers that stick on the surface must be removed prior to a repair job, it is often difficult to remove the thin layer of the castable that has been penetrated by slag. It often remains in place and serves as substrate for the repair material. In this paper, a post-mortem investigation is conducted on a newly developed dry-gunning mix that was installed in a steel ladle wall on top of a slag penetrated castable. The repair mix contains a newly designed porous aggregate as partly replacement for the dense alumina aggregate. This porous aggregate consists of magnesium aluminate and calcium aluminate microcrystals. The post-mortem study is investigating both, the corrosion of the dry-gunning mix in direct contact with steel and slag on the hot side as well as the microstructural changes at its interface to the slag penetrated castable that served as substrate for the repair mix.