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).

Compositions useful for foundry processes such as green sand casting are discussed. The compositions may comprise an aggregate, at least one inorganic binding agent, and at least one high aspect ratio silicate. For example, the composition may comprise sand, one or more clay materials serving as a binding agent, and a high aspect ratio silicate chosen from mica, talc, or a combination thereof. The composition may be formed into a green sand mold for use in casting molded articles. Incorporation of the high aspect ratio silicate may help to improve the quality of the casted article.

Compositions useful for foundry processes such as green sand casting are discussed. The compositions may comprise an aggregate, at least one inorganic binding agent, and at least one high aspect ratio silicate. For example, the composition may comprise sand, one or more clay materials serving as a binding agent, and a high aspect ratio silicate chosen from mica, talc, or a combination thereof. The composition may be formed into a green sand mold for use in casting molded articles. Incorporation of the high aspect ratio silicate may help to improve the quality of the casted article.

A composition which comprises a soluble or partially soluble phosphate, a refractory material and less than 1% of an oxide or hydroxide of magnesium or calcium. The composition may be mixed with water to form an investment casting slurry into which a wax pattern may be dipped. Slurry coated onto the pattern may be set by applying a stucco composition which comprises an oxide or hydroxide of magnesium or calcium. Coats of set slurry may be built up on the pattern to form an investment casting shell.

The invention relates to an aqueous alkaline binder composition for curing with carbon dioxide gas, comprising a negatively charged or uncharged phenol-aldehyde resin, comprising phenol groups, which is selected from the group consisting of resoles and mixtures comprising one or more resoles and also one or more novolacs, an oxyanion selected from the group consisting of borate ions, aluminate ions, stannate ions, zirconate ions, titanate ions, and mixtures thereof, for forming a stable complex with the resole phenol-aldehyde resin, and one or more silanes in a total amount in the range from 2.5 to 10 wt %, based on the total mass of the binder composition, where the total molar to amount of the phenol groups of the phenol-aldehyde resin in the aqueous alkaline binder composition is in the range from 1 to 3 mol/kg, based on the total mass of the aqueous alkaline binder composition. The invention relates, moreover, to a corresponding use, to a molding mixture for producing a foundry mold, and also to a corresponding method for producing a foundry mold, and to a corresponding foundry mold.

The invention relates to mold material mixtures containing an oxide of aluminum and an oxide of zirconium as particulate mixed metal oxide, in combination with refractory mold base materials and a water glass-based binder system. The mold material mixtures, also in the form of multicomponent systems, are used for the production of molds and cores for the foundry industry.

The invention describes a process for obtaining clay having improved characteristics that comprises incorporating an inorganic matrix onto an organic matrix at determined proportions. The industrial clay obtained is malleable and highly resistant to compression and strain, of great use in the industry of prototype elaboration.

The present invention relates to the use of closed-pore microspheres of expanded perlite as a filler for producing moldings for the foundry industry, to a composition for producing moldings for the foundry industry, comprising closed-pore microspheres of expanded perlite as a filler, and a binder, the binder being selected from the group consisting of water glass, phenol-formaldehyde resins, two-component systems comprising as reactants a polyisocyanate and a polyol component containing free hydroxyl groups (OH groups), and starch, and also to moldings for the foundry industry and to a process for producing a molding for the foundry industry.

The invention relates to mold material mixtures containing at least one aluminum oxide in the alpha phase and/or at least one aluminum/silicon mixed oxide, except for aluminum/silicon mixed oxides having a layered silicate structure, as a particulate metal oxide, in combination with refractory mold base materials and a water glass-based binder system. The mold material mixtures are used for the production of molds and cores for the foundry industry.

A slurry for forming a mold includes a silica sol as a dispersion medium and niobia-stabilized zirconia dispersed in the silica sol.