Chemical wear of Al 2 O 3 –MgO–C bricks by air and basic slag

Thermomechanical behaviour of Al2O3–MgO–C refractories under non-oxidizing atmosphere

“…A significant decrease of the apparent Young's modulus and the mechanical strength is displayed in AMC1 and AMC3 plots as the testing temperature rose to 700 1C, which is expected taking into account the chemical and textural alterations taking place in the materials above 300 1C. According to results of a previous study on the oxidation of these refractories [28], graphite oxidation began before 700 1C in AMC1, but not in AMC3. This fact was confirmed in the post-testing inspection of specimens: a slight superficial decarburization was observed in AMC1, which was almost imperceptible in AMC3.…”

“…This fact could be related to a possible reduction in open porosity in the outer layers of the cylinders due to the formation of sub-products such as soot (from: 2CO-CO 2 þ C (s) ) [26] and the closure of open micropores by resin transformation [27]. The higher susceptibility to oxidation manifested by AMC1 and AMC2 refractories, and the way this process advances in this range of temperature (which has been previously reported by the authors [28]), brings support to this hypothesis. On the other hand, AMC3 retained values of open porosity smaller than those of the other two refractories up to 1000 1C, when it matched them.…”

“…The positive effect of these reactions could be offset by other processes occurring simultaneously. In the case of AMC1, which showed more advanced reactions, there was a deceleration in the advance of graphite oxidation [28], which is a low resistant component. Meanwhile, the graphite loss was manifest only between 700 and 1000 1C in AMC3.…”

“…On the other hand, the mechanical strength dropped (from the same causes mentioned above for the other two materials), together with a significant drop in the fracture strain. Possible justification for this behavior is found in the fact that AMC2 lost a proportion of graphite somewhat higher than AMC1 at 700 1C [28]. The loss of this component reduces the capacity of the structure to deform and could compensate for the increase in this ability due to its higher porosity.…”

Microstructure, properties, and application of low carbon Al2O3‐C refractories used as submerged entry nozzles

“…It is worth noting that a homogeneous reaction front was formed at the F I G U R E 1 0 X-ray diffraction patterns of the corroded refractories extracted from the slag line of submerged entry nozzles displayed in Figure 8 interface, suggesting an improved corrosion resistance of the matrix. 33 Additionally, a higher amount of SiC phase was also detected for the low carbon refractory, as shown in Figure 10, which displayed a more dense distribution in the matrix (Figure 11). EDX analysis showed that the liquid phase near the interface contained 16.30 wt% CaO, 34.92 wt% Al 2 O 3 , 35.00 wt% SiO 2 , 1.41 wt% MgO, 5.02 wt% Na 2 O, 2.02 wt% Fe 2 O 3 , and 3.51 wt% F, being different from the initial slag.…”