"Chemical wear of Al2O3-MgO-C bricks by air and basic slags"

L.MUSANTE; P.G. GALLIANO; E. BRANDALEZE; V. MUÑOZ; A. G. TOMBA MARTINEZ

Congreso; UNITECR 2013; 2013

Al2O3-MgO-C (AMC) refractory bricks maintain their high consumption level in steelmaking plants due to their excellent properties. Besides the advantages associated to carbon flakes, i.e., the increment in thermal conductivity, thermal shock resistance and slag attack resistance, the formation of spinel (MgAl2O4) induces an expansion that helps to counterbalance the wear of the brick joint by reducing slag penetration. In this work, the oxidation and the corrosion resistance to a basic ladle slag of commercial AMC refractory bricks were evaluated. XRD, XRF, ICP-OES, DTA/TGA, density, porosity and permeability measurements, mercury intrusion porosimetry, and SEM/EDX were employed for the characterization of the refractories. The oxidation tests were performed in air between 700 and 1400°C (2 h) on cylinders ( .. in diameter, .. in height). Static corrosion tests were carried out on cubic specimens (50 mm in length) with a hole (35 mm in diameter, 30 in height) at 1400°C (2 h) in air. After test, the weight loss of oxidized samples was determined. Both types of specimens were cut in order to determine the wear of the samples. The corroded surfaces were ground and polished for image and SEM/EDS analyses in order to determine the refractory wear and the microstructure and composition of the slag-refractory interface, respectively. Decarburized areas were measured by image analysis and the mineralogical analysis of this area and the central region were performed by XRD on oxidized specimens. Differences between the oxidation and slag resistance of the studied materials were related to the composition and microstructure of each refractory.