A refractory has the form of a dry, mineral batch of fire-resistant mineral materials combined in such a way that refractories which are long-term resistant to fayalite-containing slags, sulfidic melts (mattes), sulfates and non-ferrous metal melts and are used for refractory linings in industrial non-ferrous metal melting furnaces can be manufactured. The refractory at least contains: —at least one coarse-grained olivine raw material as the main component; —magnesia (MgO) meal; —at least one fire-resistant reagent which, during the melting process, acts (in situ) in a reducing manner on non-ferrous metal oxide melts and/or non-ferrous metal iron oxide melts and converts same into non-ferrous metal melts.

A refractory has the form of a dry, mineral batch of fire-resistant mineral materials combined in such a way that refractories which are long-term resistant to fayalite-containing slags, sulfidic melts (mattes), sulfates and non-ferrous metal melts and are used for refractory linings in industrial non-ferrous metal melting furnaces can be manufactured. The refractory at least contains: —at least one coarse-grained olivine raw material as the main component; —magnesia (MgO) meal; —at least one fire-resistant reagent which, during the melting process, acts (in situ) in a reducing manner on non-ferrous metal oxide melts and/or non-ferrous metal iron oxide melts and converts same into non-ferrous metal melts.

Embodiments of the present invention encompass methods of improving flow of dry materials. Embodiments of the present invention also encompass compositions with improved flow. Embodiments of the present invention also encompass methods of using the compositions with improved flow.

The invention concerns a batch for the production of a refractory magnesia-carbon product or a refractory alumina-magnesia-carbon product, a process for the production of a refractory magnesia-carbon product or a refractory alumina-magnesia-carbon product, a refractory magnesia-carbon product or a refractory alumina-magnesia-carbon product as well as the use of a magnesia-carbon product or a refractory alumina-magnesia-carbon product.

According to the invention, by setting the linear thermal expansion amount when a mold made of a molding sand is heated from a room temperature to 1000° C. to be not more than 0.9%, and the ratio (D/d) between the diameter of a slump (D) and the diameter of a slump cone (d) in a slump test of the molding sand having a hardening agent kneaded to be not less than 1.65, a molding sand preferable for use in a mold produced using the self-hardening type of three dimensional laminate molding sand mold, having low thermal expansibility preventing occurrence of a veining defect, and capable of forming a large and complicated shape can be obtained.

A powdery composition based on silica for ceramic welding, in particular by projection, comprising from 10 to 90% of a phase of siliceous particles comprise at least 80% by weight of cristobalite and at most 15% by weight of tridymite, based on the total weight of the composition, from 90 to 10% by weight of conventional additives forming a binding phase, based on the total weight of the composition, said siliceous particles having a d.sub.50 comprised between 350 and 800 μm, preferably between 400 and 500 μm.

A powdery composition based on silica for ceramic welding, in particular by projection, comprising from 10 to 90% of a phase of siliceous particles comprise at least 80% by weight of cristobalite and at most 15% by weight of tridymite, based on the total weight of the composition, from 90 to 10% by weight of conventional additives forming a binding phase, based on the total weight of the composition, said siliceous particles having a d.sub.50 comprised between 350 and 800 μm, preferably between 400 and 500 μm.

The invention relates to a refractory product, a batch for producing the product, a method for producing the product, and a use of the refractory product.

A spray material for hot and dry spray application with improved corrosion resistance, and a hot and dry spray application method with improved corrosion resistance. A hot and dry spray application method comprises pressure-feeding a mixture comprising a refractory material and a binder, toward a spraying nozzle via a pipe, and adding water to the mixture at a distal end of the spraying nozzle to apply a spray under a hot condition. The mixture contains magnesium limestone having a particle size of 0.075 mm to less than 1 mm, in an amount of 10 mass % to 50 mass %, in 100 mass % of a total amount of the refractory material and the binder. The content of magnesium limestone having a particle size of less than 0.075 mm in 100 mass % of the total amount of the refractory material and the binder is 35 mass % or less (including 0).

The invention concerns a refractory ceramic batch as well as a refractory ceramic product.