Al2O3-based binders for corrosion resistance optimization of Al2O3–MgAl2O4 and Al2O3–MgO refractory castables

Effect of submicron spinel powders on the microstructure evolution and properties of alumina‐based refractory castables

“…In the slag layer (area I), the submicron spinel powders dissolve in the molten liquid and achieve supersaturation, leading to the further precipitation of spinel in the solid–liquid interface as a continuous and thicker spinel layer, as shown in Figure (A). Some authors have obtained similar findings . Furthermore, the Al 2 O 3 are also easy dissolved into slag through a liquid boundary layer at the alumina/slag interface .…”

“…When 5.6 wt% submicron spinel powders are added, the flow value of the castables reaches the maximum value of 230 mm. The flow properties of castables are known to be strongly influenced by the particle size distribution according to the Andreassen model . Considering the particle size distribution curves in Figure , it is assumed that submicron spinel powders are easier to fill into the pores and thus achieve close packing in the castables, resulting in the need for less amount of water.…”

“…When the castables containing 5.6 wt% submicron spinel powders are fired at 1873 K (1600°C), the maximum values of the CMOR and CCS are 45.8 and 293.1 MPa, respectively; these are 40.5% and 32.3% higher than those of castables containing 3.2 wt% submicron spinel powders. According to the particle size distribution theory, fine powders show a high packing density. Further, powders processed by high‐energy milling have higher reactivity, and submicron spinel with high reactivity promotes the sintering of the spinel and aggregate/matrix, leading to high bonding strength.…”

“…Mori reported that the addition of 10‐30 wt% alumina‐rich spinel resulted in superior slag resistance properties in alumina spinel castables, the life of castables was twice as long as that of high‐alumina bricks. Furthermore, the size of spinel powders was found to affect the mechanical properties and thermal shock properties of castables, wherein fine powders are more effective than coarse grains in resisting corrosion . Aksel reported that castables containing spinel powders had less cracks, resulting in high mechanical properties.…”

Research of Al2O3-SiC-C refractories as chromia-free lining for gasifier

“…6). It was obvious that new phases such as anorthite had formed in these areas [17][18][19]. Besides, a few iron and spinel particles could be found in the penetration layer.…”