In the present study, the effect of fume silica content on preformed and in situ spinel containing alumina spinel castable was studied by varying fume silica content at 1 and 4 wt.%. Spinel content for preformed alumina spinel castables varied from 10 to 30 wt.% and MgO content for in situ alumina spinel castables varied from 2.8 to 8.4 wt.%, respectively, and the distribution coefficient (q value) was maintained at .21 and .29 as per Dinger and Funk model. Different castable compositions were processed as per conventional processing technique and further evaluated for densification and strength studies after heat treatment at 110, 1000, and 1550 • C. Fired samples at 1550 • C were further evaluated for the hot modulus of rupture study at 1400 • C and phase analysis study of the matrix phase. Also, the fired samples were studied for microstructural evaluation. K E Y W O R D Salumina spinel castable, calcium hexa-aluminate (CA 6 ), fume silica content, preformed and in situ spinel 1

Alumina‐spinel castable has excellent refractory properties, including high volume and thermal stability, good hot strength, and excellent resistance against corrosion, erosion, and thermal spalling. Excellent refractory properties have made it a preferred lining for steel ladles, reducing the erosion and corrosion of molten metal and slag and improving the ladle life and efficiency for decades. These castables are also significant for the replacement of chrome‐bearing refractories that cause several health hazards. The current review paper covers preformed and in situ spinel containing alumina castables. It focuses on the importance of these castables in the sidewall and bottom portion of the steel ladle in detail, the effect of spinel and MgO content, and the factors affecting castable properties. The review also covers the final properties of castable and the application areas of alumina‐spinel castable in steel ladle, purging plugs, and RH‐degasser.

The effect of adding yttria (Y 2 O 3 ) up to 2 wt.% on low cement high alumina castable is studied. Castable compositions with self-flowing and vibratable consistency (distribution coefficients, q = 0.21 and 0.29) are prepared using commercial raw materials and processed as per the conventional processing route, cured at 110°C, and fired at 1000 and 1550°C. An increase in yttria content is found to improve the physical and mechanical properties of castables for all temperatures. Phase analysis confirms the formation of the yttrium aluminate phase, and microstructural evaluation at 1550°C indicates enhanced bonding between the matrix and aggregate phase resulting in better density and strength properties.