A molding material in a powder-fixing lamination method includes an aggregate and a powdery precursor of a binder that binds the aggregate mutually. The aggregate is a casting sand, and the powdery precursor contains a hardening component and a hardening accelerating component. A molded product is manufactured using the molding material.

A curing agent for water glass molding comprises: ester; amorphous silica; and water. The amorphous silica is formed by means of a pyrolysis method and/or by means of a precipitation method. Also disclosed is a use of the curing agent for water glass molding in preparation of a casting mold and a mold core. Respective components of the curing agent comprising ester, amorphous silica and water are mixed at a high speed to form a suspension. Next, the suspension is applied to prepare a water glass self-hardening sand. The curing agent does not cause powder contamination, and can be measured and added conveniently. Also disclosed are a manufacturing method of the curing agent for water glass molding and a water glass self-hardening sand.

Purposes of the present invention are to provide a dry coated sand having a high degree of fluidity at the room temperature, a method of advantageously producing the coated sand, and a method of producing a casting mold having excellent properties, by using the coated sand. The dry coated sand is obtained by mixing an aqueous solution of a water glass used as a binder, with a heated refractory aggregate, whereby water in the aqueous solution is evaporated, and a coating layer of the binder is formed on surfaces of the refractory aggregate. A moisture percentage in the thus obtained dry coated sand is controlled so as to be not more than 0.5% by mass. The intended casting mold is obtained by filling a molding cavity of a forming mold, with the dry coated sand, and passing a steam through the coated sand, to solidify or cure the coated sand.

A sand mold-forming additive capable of making a sand mold-forming composition having excellent forming property and a sand mold having excellent moisture resistance is provided. The sand mold-forming additive contains 0.01-2.00 parts by weight of an inorganic alkali metal compound (B) per 100 parts by weight of anionic surfactant (A). The inorganic alkali metal compound (B) is at least one selected from sodium chloride and sodium sulfate. The ionic surfactant (A) is preferably at least one selected from alkyl sulfonic acid metal salts (A1), alkyl sulfuric acid metal salts (A2), and polyoxyalkylene alkyl ether sulfuric acid ester metal salts (A3).

The present invention relates to a dry refractory paint precursor composition comprising, 5 to 55 wt.-% mineral filler, 20 to 45 wt.-% glass frit comprising SiO.sub.2, Na.sub.2O, B.sub.2O.sub.3 and/or Al.sub.2O.sub.3, and 0.1 to 25 wt.-% of a binder selected from waterglass, cement and mixtures thereof, all based on the total weight of the composition. The invention further relates to refractory paints comprising said compositions, and to methods for preparing said paints.

The present invention relates to a dry refractory paint precursor composition comprising, 5 to 55 wt.-% mineral filler, 20 to 45 wt.-% glass frit comprising SiO.sub.2, Na.sub.2O, B.sub.2O.sub.3 and/or Al.sub.2O.sub.3, and 0.1 to 25 wt.-% of a binder selected from waterglass, cement and mixtures thereof, all based on the total weight of the composition. The invention further relates to refractory paints comprising said compositions, and to methods for preparing said paints.

Inorganic coated sand in a dry state having refractory aggregate; and an inorganic binder layer formed on a surface of the refractory aggregate, in which the inorganic binder layer contains a metasilicate hydrate.

Various embodiments of a slurry composition for investment casting and a method of forming such composition are disclosed. The slurry composition can include a refractory material, a binder, a solvent, and a thixotropic agent that includes fibrillated fibers. The slurry composition can also include a filler that includes glass bubbles.

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.

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.