POST-MORTEM ANALYSIS OF ALUMINA-MAGNESIA-CARBON REFRACTORY MATERIAL OF STEELMAKING USE

In this work, the post-mortem study of an alumina-magnesia-carbon (AMC) brick that was used in the bottom of a steelmaking ladle was carried out by scan electronic microscopy coupled with X-Ray dispersive energy spectroscopy (SEM/EDS), X-ray diffraction, differential thermal (DTA) and thermogravimetric (TGA) analyses, and density and porosity measurements. Samples were cut to different distances from the working face brick and the results are compared with those obtained in the characterization of the virgin material (unused), in order to determine the degradation of the refractory in service. The formation of new faces that evidences the interaction whit slag during the service of material was observed. Besides, it was determined that: the resin used as binder pirolyzes in service, the post-mortem material retains at least part of the initial content of graphite, and the magnesia contained in the refractory reacts completely during the use of brick producing MgAl2O4 spinel.