The invention concerns a method of manufacturing a shell mould (1) with several layers (2, 3, 4, 5), including at least one contact layer (2), from a model (6) of wax or other similar material of a part to be manufactured, the method comprising a step of dipping the model (6) into a contact slip forming the contact layer (2) and comprising an inorganic or organic binder and a powder, wherein the powder is a mullite-zirconia composite.

Apparatus and methods for making a sand core in a core box are provided. According to one embodiment, the method includes introducing into a cavity of the core box a sand-binder mixture, the sand-binder mixture being introduced into the cavity through an inlet conduit of the core box. Pressurized air is then introduced into the cavity while a flow rate of the pressurized air is measured in a first air flow path upstream the core box. A control unit automatically alters the degree of opening of an electronically controlled flow regulator located in a second air flow path located downstream an outlet conduit of the core box depending on the measured flow rate to regulate the flow of pressurized air into the cavity of the core box.

Apparatus and methods for making a sand core in a core box are provided. According to one embodiment, the method includes introducing into a cavity of the core box a sand-binder mixture, the sand-binder mixture being introduced into the cavity through an inlet conduit of the core box. Pressurized air is then introduced into the cavity while a flow rate of the pressurized air is measured in a first air flow path upstream the core box. A control unit automatically alters the degree of opening of an electronically controlled flow regulator located in a second air flow path located downstream an outlet conduit of the core box depending on the measured flow rate to regulate the flow of pressurized air into the cavity of the core box.

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, where the total molar 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, and where the phenol-aldehyde resin possesses an average molecular weight (Mw) in the range from 750 to 1200 g/mol, determined by means of gel permeation chromatography. The invention relates, moreover, to a corresponding use, to a molding mixture for producing a foundry molding, and also to a corresponding method for producing a foundry molding, and to a corresponding foundry molding.

A method for manufacturing a structure from a granular material, called sand, in particular a mold. A layer of sand is deposited. The layer of sand is selectively agglomerated by spraying, using a spray nozzle, an inorganic binder having an M2SiO3 type (meta)silicate dissolved in a solvent. Prior to the spraying, the inorganic binder is heated to a temperature to confer on it a viscosity less than 0.2 Pa.Math.s. A device for implementing the method is provided.

Various embodiments of making an investment casting mold are disclosed. The method includes coating a sacrificial pattern with a prime layer that includes a first refractory slurry and a first refractory stucco; at least partially hardening the prime layer; and coating the prime layer with an intermediate layer that includes a second refractory slurry and a second refractory stucco. The method further includes at least partially hardening the intermediate layer; coating the intermediate layer with a first backup layer that includes a first thixotropic agent, the first thixotropic agent including a first polymer emulsion; coating the first backup layer with a second backup layer that includes a second thixotropic agent, the second thixotropic agent including a second polymer emulsion; and at least partially hardening the first backup layer and the second backup layer.

Clay materials useful as binding agents in green sandcasting and other molding processes are discussed, as well as methods of preparing such clay materials. The clay materials may be chemically treated. For example, a natural clay may be combined with one or more reducing agents, such that an amount of iron present as ferric iron (Fe.sup.3+) in the natural clay is at least partially reduced to ferrous iron (Fe.sup.2+) in the chemically-treated clay. The chemically-treated clay may exhibit greater water absorption, binding properties, and/or sintering properties as compared to an untreated, natural clay.

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.