An ultra-low thermal mass refractory article includes fibers impregnated with a colloidal inorganic oxide. The refractory article has at least one of the following properties: (i) a density of 500 kg/m.sup.3 to 1500 kg/m.sup.3; (ii) a thermal conductivity of 1.0 Wm/K or less at 700° C.; and/or (iii) a linear thermal shrinkage at 1400° C. of less than 2.5%.

Disclosed is a method for preparing an uncalcined geopolymer-based refractory material. The method includes the steps of mixing a mineral powder, a fly ash, a metakaolin, and silicon carbide whiskers by ball milling to form a milled material; mixing the milled material with a sodium water glass solution and water to form a slurry; and curing the slurry to obtain the uncalcined geopolymer-based refractory material. The uncalcined geopolymer-based refractory material thus prepared contains a geopolymer matrix formed of the mineral powder, the fly ash, and the metakaolin and the silicon carbide whiskers embedded in the geopolymer matrix.

To improve the stability of spray application of a monolithic refractory in which a water injector is disposed in a material carrier pipe extending from a material supply device to a distal spray nozzle, and application water is injected from the water injector into a spray material that is being carried through the material carrier pipe, a ratio of a flow volume of an application water carrier gas for carrying the application water to be introduced into the water injector to a flow volume of a spray material carrier gas for carrying the spray material is set to 0.07 to 2, and a compressibility index of the spray material is set to 32% or less. Alternatively, a ratio of a flow volume of an application water carrier gas for carrying the application water to be introduced into the water injector to an application water volume is set to 100 to 1,000.

To improve the stability of spray application of a monolithic refractory in which a water injector is disposed in a material carrier pipe extending from a material supply device to a distal spray nozzle, and application water is injected from the water injector into a spray material that is being carried through the material carrier pipe, a ratio of a flow volume of an application water carrier gas for carrying the application water to be introduced into the water injector to a flow volume of a spray material carrier gas for carrying the spray material is set to 0.07 to 2, and a compressibility index of the spray material is set to 32% or less. Alternatively, a ratio of a flow volume of an application water carrier gas for carrying the application water to be introduced into the water injector to an application water volume is set to 100 to 1,000.

A process for the manufacture of a refractory block including more than 80% zirconia, in percentage by weight based on the oxides. The process includes the following successive stages: melting, under reducing conditions, of a charge including more than 50% zircon, in percentage by weight, such as to reduce the zircon and obtain a molten material, application of oxidizing conditions to the molten material, casting of the molten material, and cooling until at least partial solidification of the molten material in the form of a block. Also, the process can include heat treatment of the block.

The present invention relates to a process for the production of fiber-reinforced composite materials with an ultra-refractory, high tenacity, high ablation resistant matrix with self-healing properties, prepared from highly sinterable slurries. The composite material is produced using techniques of infiltration and drying at ambient pressure or under vacuum, and consolidated by sintering with or without the application of gas or mechanical pressure.

The present invention relates to a process for the production of fiber-reinforced composite materials with an ultra-refractory, high tenacity, high ablation resistant matrix with self-healing properties, prepared from highly sinterable slurries. The composite material is produced using techniques of infiltration and drying at ambient pressure or under vacuum, and consolidated by sintering with or without the application of gas or mechanical pressure.

A ceramic liner can include a monolithic body having a surface portion and a bulk portion. The surface portion can have a thickness less than the total thickness of the monolithic body. The monolithic body can include an amorphous phase. The amorphous phase can be discontinuous. At least one member of the discontinuous phase can be embedded in the surface portion. The bulk portion can be substantially free of the amorphous phase. A method of forming a ceramic liner can include providing a furnace with a coating and a bulk material of the ceramic liner and heating the bulk material and the coating. In an embodiment, a coated lining form can be used to provide the coating. In a particular embodiment, the coating can be transferred to the bulk material from the coated lining form.

A ceramic liner can include a monolithic body having a surface portion and a bulk portion. The surface portion can have a thickness less than the total thickness of the monolithic body. The monolithic body can include an amorphous phase. The amorphous phase can be discontinuous. At least one member of the discontinuous phase can be embedded in the surface portion. The bulk portion can be substantially free of the amorphous phase. A method of forming a ceramic liner can include providing a furnace with a coating and a bulk material of the ceramic liner and heating the bulk material and the coating. In an embodiment, a coated lining form can be used to provide the coating. In a particular embodiment, the coating can be transferred to the bulk material from the coated lining form.

A refractory composition including refractory aggregate, one or more matrix components, and silicate-coated set accelerator particles. The silicate-coated set accelerator particles can include one more of silicate-coated calcium hydroxide, magnesium hydroxide, calcium chloride, calcium carbonate, magnesium carbonate and calcium sulfate. Suitable silicate coatings include sodium silicate, potassium silicate, lithium silicate and mixtures thereof. A method of recovering an aged refractory composition, a settable composition and a method of manufacturing silicate-coated calcium hydroxide particles are also provided.