The invention relates to a method for producing lost cores or molded parts for the production of cast parts, in which a basic molding material is mixed with an alkali silicate or water glass binder and a lost core or a molded part for the production of cast parts is formed using a core shooter in a core box, wherein the alkali silicate or water glass binder contains an alkali silicate or water glass solution having a modulus of 1.5 to 3.5 and natural and/or synthetic additives in a proportion of 0.1 to 25% by weight measured with respect to the total amount of binder, with a particle size of less than 5 m and the natural and/or synthetic additives are at least aluminum silicate, magnesium silicate and sodium aluminum silicate, each having a proportion of 1 to 5% by weight measured with respect to the total amount of binder. The lost core or the other molded part is formed in an unheated core box, and the lost core thus formed or the molded part is cured using hot air.

A method of reusing core sand includes crushing a core used for casting into granules; heating the granules at a temperature of 300 C. to 550 C.; causing the heated granules to collide against each other such that water glass used as a binder detaches from the core sand; and blowing air into a mixture of the water glass and the core sand, which are detached from each other, such that the core sand is separated and collected from the mixture due to a difference in specific gravity between the water glass and the core sand.

The invention relates to lithium-containing molding material mixtures comprising a refractory main molding material, an inorganic binder, and amorphous silicon dioxide as an additive in the production of molds and cores for metal casting. The invention further relates to a method for producing molds and cores using the molding material mixtures and to molds and cores produced according to the method.

A surfactant composition for a foamed sand including 80 to 99.8 mass % of a compound (A) represented by formula (1); 0.1 to 10 mass % of a compound (B) represented by formula (2); and 0.1 to 10 mass % of an amphoteric surfactant (C):
R.sup.1O-(EO).sub.nSO.sub.3M.sup.1(1)
wherein R.sup.1 represents a hydrocarbon group having 6 to 22 carbons, EO represents oxyethylene group, n is 1 to 10, and M.sup.1 represents an alkali metal, an alkaline earth metal, ammonium or an organic ammonium;
R.sup.2OSO.sub.3M.sup.2(2)
wherein R.sup.2 represents a hydrocarbon group having 6 to 22 carbons, and M.sup.2 represents an alkali metal, an alkaline earth metal, ammonium or an organic ammonium.

What are described are the use of a refractory coating composition for production of cores for diecasting, a kit for production of cores for use in diecasting, a method of producing cores for use in diecasting, cores for use in diecasting, and the use of such cores in diecasting, especially of lightweight metals.

The present invention relates to methods for the layered construction of molds and cores that include refractory molding base material, a hydrophobized metal oxide as solids and a binder containing at least water glass in the form of an aqueous alkali silicate solution. The methods involve applying a refractory molding base material in layers and selectively print the molds and cores using the binder. The present invention further relates to molds or cores produced in accordance with these methods.

A description is given of the use of an additive mixture (A) for combination with a solution or dispersion (B) comprising waterglass, for producing a moulding material mixture for producing articles from the group consisting of foundry moulds and foundry cores; a multi-component binder system comprising (A) an additive mixture and (B) a solution or dispersion comprising waterglass; a moulding material mixture comprising a mould base material (C) and also components (A) and (B) of such a multi-component binder system; a method for producing an article from the group consisting of foundry moulds and foundry cores; articles from the group consisting of foundry moulds and foundry cores; and the use of such an article for metal casting, preferably for light metal casting, more particularly for aluminium casting.

A composition for making cores and a process for metal casting, the composition comprising: a particulate refractory material; an inorganic binder comprising at least one alkali metal silicate; a pozzolanic additive; and a lustrous carbon former. The process includes forming a core from the composition and assembling a mould comprising the core and supplying molten metal.

The invention relates to molding material mixtures containing barium sulfate in combination with refractory basic molding materials and a waterglass-based binder system for producing casting molds and cores for the foundry industry in order to obtain cast pieces, in particular aluminum ones, which have an improved cast surface.

The invention relates to molding material mixtures containing a molding base material, water glass, amorphous silicon dioxide and an oxidic boron compound, and the production of molds and cores, in particular for metal casting.