Abstract: Alumina-spinel monolithic refractory having excellent spalling resistance, corrosion resistance and slag penetration resistance. The alumina-spinel refractory contains an alumina-spinel clinker having a MgO:Al.sub.2 O.sub.3 molar ratio ranging from 0.14:1.86 to 0.6:1.4 which can be simultaneously used with a spinel clinker having a close to theoretical composition with the balance consisting of an alumina material and alumina cement. Also, in order to inhibit the elongation of cracks an alumina crushed grain having a grain size ranging from 10 to 50 mm can be added to the alumina-spinel monolithic refractory.

Abstract: The present invention relates to a two-part gunning refractory composition wherein fine powders of a refractory aggregate and superfine refractory powders are previously made into the form of a slurry containing therein a deflocculant, thereby reducing the amount of aluminous cement and also reducing the amount of water to achieve a deposit applied by gunning having a quality comparable to one produced by casting.

Abstract: A low cement refractory gun mix is disclosed. The gun mix comprises a coarse refractory portion having a particle diameter of at least 74 microns and a fine powder portion having a particle diameter of at most 74 microns. The gun mix is prepared by forming the fine powder portion into a slurry and deflocculating it prior to mixing it with the coarse refractory portion rather than deflocculating it when it is introduced into a spray gun. The gun mix has an extremely low cement and water content. Accordingly, a sprayed deposit of high packing density can be obtained which is equal in quality with deposits produced by vibration molding or casting. The gun mix is appropriate for use in forming the entire work lining of containers for molten metal.