Grains for the production of a sintered refractory product, a batch for the production of a sintered refractory product, a process for the production of a sintered refractory product and a sintered refractory product

A foamed lightweight monolithic refractory castable is provided. The castable includes one or more refractory aggregates as a main constituent, one or more foaming additives in a range of 0.1 wt % to 3.0 wt %, one or more cellulosic powder air-entraining additives in a range of 0.005 wt % to 2.0 wt %, one or more binders in a range of 1 wt % to 40 wt %, and one or more superplasticizers in a range of 0.05 wt % to 0.5 wt %. The refractory aggregates include at least one of alumina and silica. The foaming additives include at least one of alkylbenzene sulfonates, alkene sulfonates, and hydroxylalkane sulfates. The superplasticizers include at least one of sodium polyacrylates, naphthalene sulfonates, polyethylene glycols, polycarboxylates, polyacrylates, and polycarboxylate ethers.

The use of magnesium oxide, reactive alumina and aluminium oxide as a base provides for a new erosion-resistant material upon sintering.

A porous refractory in the K.sub.2O—SiO.sub.2—B.sub.2O.sub.3 system is formed by chemical direct foaming by heating to over 600° C., resulting in adherent black or white foam. The foam can function as highly porous thermal insulation, a high or low thermal emissivity surface, as a sealant for deteriorated refractory surfaces, as a filler for pockmarks/holes/gaps or as a bonding agent for parts with large gaps between them.

A porous refractory in the K.sub.2O—SiO.sub.2—B.sub.2O.sub.3 system is formed by chemical direct foaming by heating to over 600° C., resulting in adherent black or white foam. The foam can function as highly porous thermal insulation, a high or low thermal emissivity surface, as a sealant for deteriorated refractory surfaces, as a filler for pockmarks/holes/gaps or as a bonding agent for parts with large gaps between them.

The use of magnesium oxide, reactive alumina and aluminium oxide as a base provides for a new erosion-resistant material upon sintering.

A glass furnace including an additive-containing product including an additive selected from: phosphorus compounds other than glasses and vitroceramics, tungsten compounds other than glasses and vitroceramics, molybdenum compounds other than glasses and vitroceramics, iron in the form of metal, aluminum in the form of metal, silicon in the form of metal, and their mixtures, silicon carbide, boron carbide, silicon nitride, boron nitride, glasses including elemental phosphorus and/or iron and/or tungsten and/or molybdenum, vitroceramics including elemental phosphorus and/or iron and/or tungsten and/or molybdenum, and their mixtures, and having the following chemical analysis, exclusively of the additive, as a percentage by weight on the basis of the oxides: Cr.sub.2O.sub.32%, and Cr.sub.2O.sub.3+Al.sub.2O.sub.3+CaO+ZrO.sub.2+MgO+Fe.sub.2O.sub.3+SiO.sub.2+TiO.sub.290%, and Cr.sub.2O.sub.3+Al.sub.2O.sub.3+MgO60%, the content by weight of additive being in the range 0.01% to 6%.

A method of making a refractory article is provided. The method includes: a) mixing a binder system, a refractory charge, and a second colloidal binder to form an aqueous slurry; b) casting the aqueous slurry into a mold; c) subjecting the mold containing the aqueous slurry to a temperature that is lower than a slurry casting temperature for a time sufficient to form a green strength article; and d) firing the green strength article at a temperature of at least 450 C. for a time sufficient to achieve thermal homogeneity, thereby forming a refractory article. Refractory articles made in accordance with the method have a unique combination of pore structure and mechanical properties.

Processes of forming or repairing a structure for use in high temperature applications may include intermixing a sodium nitrite (NaNO.sub.2) additive with a refractory material; and applying the refractory material to a structure surface.

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.