The present invention relates to the selection of materials for methods for producing moulds (2) or cores (2) for foundry purposes. When selecting the core box material, a special ceramic, such as for example silicon carbide or silicon nitride, is used instead of metals such as steel or aluminium. It is essential for the inventionthat a material (7) for receiving the mixture (9) is introduced into a housing (3), the material consisting of silicon carbide or silicon nitride, that electrical energy is supplied to the material (7) by way of electrodes (10) arranged in/on the housing (3) and in this way heat is supplied, leading to curing of the mixture (9). This allows longer service lives to be achieved for the core boxes as a result of low abrasive wear.

The invention relates to core-shell particles for use as a filler for feeder compositions for producing feeders, comprising (a) a core which possesses one or more cavities and a wall surrounding these cavities, where the core (a) has an average diameter in the range from 0.15 to 0.45 mm, (b) a shell enclosing the core and consisting of or comprising (b1) particles comprising or consisting of a material from the group consisting of calcined kaolin or cordierite, where the particles (b1) have a d10 of at least 0.05 m and a d90 of at most 45 m, and also (b2) a binder which binds the particles (b1) to one another and to the core (a).

The invention relates to core-shell particles for use as a filler for feeder compositions for producing feeders, comprising (a) a core which possesses one or more cavities and a wall surrounding these cavities, where the core (a) has an average diameter in the range from 0.15 to 0.45 mm, (b) a shell enclosing the core and consisting of or comprising (b1) particles comprising or consisting of a material from the group consisting of calcined kaolin or cordierite, where the particles (b1) have a d10 of at least 0.05 m and a d90 of at most 45 m, and also (b2) a binder which binds the particles (b1) to one another and to the core (a).

The present invention relates to methods for forming bonded particulate refractory materials for use in metal-working, comprising the steps of providing a fine particulate metal oxide, providing an aqueous alkaline composition, providing a particulate refractory mould material, mixing the said fine particulate metal oxide, the said aqueous alkaline composition and the said particulate refractory mould material, and shooting the obtained mixture in a core shooter. Substantially all the water included in the obtained mixture is derived from the aqueous alkaline solution and optionally the surfactant. Also part of the present invention are materials and articles obtained according to the method, as well as particulate compositions for use in the method.

A structure for manufacturing castings, containing an inorganic fiber, a layered clay mineral, and an inorganic particle other than the layered clay mineral and having an organic content of 5 mass % or lower or having a mass loss of 5 mass % or lower when heated at 1000 C. for 30 minutes. The inorganic particle preferably contains one or more selected from obsidian, graphite, and mullite. The inorganic fiber preferably contains carbon fiber. The inorganic fiber preferably has an average length of 0.5 to 15 mm. The layered clay mineral preferably contains one or more selected from bentonite and montmorillonite.

A method of manufacturing molds and cores suitable for producing fiber composite bodies or cast parts of metal or plastic from a mold base material and a multicomponent binder by 3D printing includes pretreating the particulate mold base material with at least one silicon-organic compound having a polar hydrophilic end and a nonpolar hydrophobic end, forming a layer of the pretreated particulate mold base material, and applying the binder or at least one component of the binder in liquid form to the layer, wherein b. and c. are repeated.

A method of manufacturing molds and cores suitable for producing fiber composite bodies or cast parts of metal or plastic from a mold base material and a multicomponent binder by 3D printing includes pretreating the particulate mold base material with at least one silicon-organic compound having a polar hydrophilic end and a nonpolar hydrophobic end, forming a layer of the pretreated particulate mold base material, and applying the binder or at least one component of the binder in liquid form to the layer, wherein b. and c. are repeated.

The present invention intends to provide a gypsum-based embedding material composition for casting, the composition being useful as a rapid-heating type gypsum-based embedding material making it possible to provide a product with which leaving time is made short, which has never been realized in conventional products, and also intends to provide a method for producing the same. A gypsum-based embedding material composition for casting, the composition being a gypsum-based powdery embedding material composition for casting to be used for a rapid-heating type embedding material, the gypsum-based powdery embedding material composition being such that a set product is put into a high-temperature furnace, the set product obtained by adding a malaxation liquid into the composition to perform malaxation and then setting a resultant mixture, wherein the gypsum-based embedding material composition for casting contains as main components calcined gypsum, quartz, and cristobalite, and contains at least one co-pulverized material selected from a co-pulverized material of calcined gypsum and quartz, a co-pulverized material of calcined gypsum and cristobalite, or a co-pulverized material of calcined gypsum, quartz, and cristobalite, and a powdery moisture-retaining component or a liquid moisture-retaining component having a low water content, the composition having an average particle diameter of 30 m or less, and a method for producing the same.

Provided are: a coated sand having improved fluidity and being capable of improving a filling rate of a casting mold to be obtained; and a coated sand for advantageously manufacturing a casting mold having excellent strength, which coated sand provides a casting mold with good mold-releasability and collapsibility, gives cast products a favorable casting surface, and effectively improves sand adhesion on cast products. The coated sand is formed as a dry granular material having fluidity at room temperature, in which the surface of a refractory aggregate is coated with a solid layer of a water-soluble inorganic binder, and spherical particles of silicone resin having binder-repellency exist on the surface of the binder layer, or form a layer on the surface of the binder layer, a part of the spherical particles being not covered with the water-soluble inorganic binder and being exposed.

Provided are: a coated sand having improved fluidity and being capable of improving a filling rate of a casting mold to be obtained; and a coated sand for advantageously manufacturing a casting mold having excellent strength, which coated sand provides a casting mold with good mold-releasability and collapsibility, gives cast products a favorable casting surface, and effectively improves sand adhesion on cast products. The coated sand is formed as a dry granular material having fluidity at room temperature, in which the surface of a refractory aggregate is coated with a solid layer of a water-soluble inorganic binder, and spherical particles of silicone resin having binder-repellency exist on the surface of the binder layer, or form a layer on the surface of the binder layer, a part of the spherical particles being not covered with the water-soluble inorganic binder and being exposed.