Revisiting CA6 formation in cement-bonded alumina-spinel refractory castables

Effect of reclaimed bauxite on andalusite-based refractory castables for tundish applications

“…As such, the observed decrease in the bulk density with an increase in the amount of grog is likely to affect such high-temperature properties of the castable. As a result, it is important to further optimize the amounts of grog, reactive calcined alumina, and microsilica addition to enhance the packing density, and the nature and amount of bonding phases in the formulated castables (Pivinskii, 1998;Zawrah and Khalil, 2001;Parr, Fryda, and Wöhrmeyer, 2013;Sadik, El-Amraniand, and Albizane, 2014;Tomba-Martinez et al, 2017). Table VII shows the chemical composition of the slag used in the static corrosion tests.…”

“…Furthermore, it can be inferred that the slagcastable interaction occurred via the slag penetrating through the available pathways (open pores, cracks, phase boundaries, etc. ), with the degree of penetration being controlled by the bulk density and apparent porosity of the castables (Pivinskii, 1998;Zawrah and Khalil, 2001;Poirier et al, 2008;Braulio et al, 2011;Sako, Braulio, and Pandolfelli, 2012;Parr, Fryda, and Wöhrmeyer, 2013;Kumar et al, 2014;Sadik, El-Amraniand, and Albizane, 2014;Tomba-Martinez et al, 2017). Thus, the corrosion behaviour indicates the need to further optimize the bulk density and open porosity properties of the formulated castables.…”

“…The volume and distribution of the mullite and corundum phases is particularly critical to the performance of the formulated castables. Mullite, in particular, provides chemical stability to resist corrosion attack, and as such, the better corrosion resistance of S1, S2, and S3 can be attributed to the increased amounts of these phases in the castables (Zawrah and Khalil, 2001;Rebouillat and Rigaud, 2002;Garbers-Craig, 2008;Abou-Sekkina et al, 2011;Frulli, 2016;Tomba-Martinez et al, 2017). Although S4 was expected to have higher resistance to slag attack due to the greater amounts of mullite and corundum phases, the integrity of the formulation was negated by synergistic effects of poor physicochemical properties such as bulk density and open porosity (Kumar et al, 2014).…”

Preparation of Al2O3@CaCO3 aggregates and its effects on the thermal shock resistance of Al2O3‐MgO castables

“…Platelet-or plate-like calcium hexaaluminate (CaAl 12 O 16 , often denoted as CA 6 ) is widely used as toughening phase in ceramic matrix composites because of its special morphology, which is prone to make cracks propagate along its cleavage face, and the crack propagation path becomes tortuous and the internal thermal stress is buffered. [10][11][12] Many studies have found that platelet-or plate-like CA 6 can be produced by introducing Ca 2+ in different forms into castables, which can effectively improve the TSR of refractory castables.…”

Formation of ferrospinel layer at the corroded interface between Al2O3‐spinel refractory and molten steel in RH refining ladle

“…CaO in the castable's matrix (from calcium aluminate cement) leads to the formation of CaO-Al 2 O 3 -SiO 2 low-melting phases, degrading its creep and corrosion resistance. [22][23][24] Given this, a variety of new bonding systems, including hydratable aluminas, gels, and phosphates, were used instead to develop cement-free corundum-spinel castables with further improved corrosion resistance. 1,[25][26][27] Obviously, previous studies mainly focused on the interactions between refractory castables and molten slag in the various refining ladles.…”