What are described is a process for producing casting molds, cores and mold base materials regenerated therefrom, a mixture for combination with a solution or dispersion comprising waterglass for production of casting molds and/or cores, a molding material mixture, a mold base material mixture, and a casting mold or a core. What is also described is the corresponding use of an amount of particulate sheet silicates having a d.sub.90 of less than 45 μm or a corresponding mixture as additive for production of a molding material mixture comprising waterglass and particulate amorphous silicon dioxide, which is cured by chemical reaction of constituents of the molding material mixture with one another, in the production of a casting mold or a core, to facilitate the breakdown and/or to increase the regeneratability of the casting mold or core.

An expandable aggregate mixture for a mold, which contains an aggregate, a water-soluble binder, a water-soluble foaming agent, water, and spherical metal oxide particles.

An expandable aggregate mixture for a mold, which contains an aggregate, a water-soluble binder, a water-soluble foaming agent, water, and spherical metal oxide particles.

A method for inorganic binder casting, comprising: selecting a Shape-Forming Material based on pre-determined manufacturing and shape characteristics, selecting a casting shape based on pre-determined design characteristics, and forming the Shape-Forming Material into a mold. The mold is coated with an inorganic binder solution at a pre-defined weight ratio and is dehydrated the Shape-Forming Material. The method further comprises pouring a hot liquid metal into the mold and allowing said hot liquid metal to cool to form a molded part. The Shape-Forming Material may be washed from said molded part with a solvent, the inorganic material and Shape-Forming Material reclaimed, reused, and the Shape-Forming Material reformed to a mold. The method further comprises recreating a liquid inorganic binder solution using the reclaimed inorganic material and recoating the Shape-Forming Material with the reclaimed inorganic binder solution.

A method of reusing core sand includes crushing a core used for casting into granules, the core includes water glass as a binder, and the water glass includes water-soluble water glass and water-insoluble water glass; heating the core; detaching the water glass from the core sand; and separating and collecting the core sand from a mixture of the water glass and the core sand.

What are described is a process for producing casting molds, cores and mold base materials regenerated therefrom, a mixture for combination with a solution or dispersion comprising waterglass for production of casting molds and/or cores, a molding material mixture, a mold base material mixture, and a casting mold or a core. What is also described is the corresponding use of an amount of particulate sheet silicates having a d.sub.90 of less than 45 μm or a corresponding mixture as additive for production of a molding material mixture comprising waterglass and particulate amorphous silicon dioxide, which is cured by chemical reaction of constituents of the molding material mixture with one another, in the production of a casting mold or a core, to facilitate the breakdown and/or to increase the regeneratability of the casting mold or core.

A method of reusing core sand includes crushing a core used for casting into granules, the core includes water glass as a binder, and the water glass includes water-soluble water glass and water-insoluble water glass; heating the core; detaching the water glass from the core sand; and separating and collecting the core sand from a mixture of the water glass and the core sand.

The invention relates to a composition for forming a casting mold, the composition containing heat-resistant inorganic particles; a waterglass-based binder; a surfactant; a silicon-containing compound; activated carbon powder and grain; and water; and the silicon-containing compound contains at least one of metal silicon and ferrosilicon.

The invention relates to a method for more quickly producing molds (2) or cores (2′) for foundry purposes by adapting the specific electrical resistance in the selection of the core box to the mixture (9) of a molding material and of a water-containing binder, which binder, when dissolved, forms an electrolyte and has a sufficient electrical conductivity. It is essential to the invention that an electrically conductive material (7) for holding the mixture (9) is introduced into an electrically non-conductive housing (3), wherein the specific electrical conductivity of the material (7) at operating temperature (7) at least approximately corresponds to the specific electrical conductivity of the mixture (9) at temperatures between 100° C. and 130° C., and that electrical energy and thus heat are supplied to the material (7) via electrodes (10) arranged in/on the housing (3) (resistance heating principle), leading to curing of the mixture (9). Depending on the sand core, up to 30% shorter cycle times can be achieved.

A description is given of a method for producing a molding material mixture or for producing a molding material mixture and a molding therefrom, preferably casting molds or cores, for use in the foundry industry, where the molding material mixture comprises a mold base material and a solution or dispersion comprising lithium-containing waterglass, comprising the following steps: (1) producing or providing a kit at least comprising as separate components: (K1) an aqueous solution or dispersion comprising waterglass and (K2a) a first waterglass-free solution or dispersion comprising lithium ions in solution in water, and also preferably (K2b) a second waterglass-free solution or dispersion, preferably comprising lithium ions in solution in water with a lower concentration than in component (K2a), and thereafter (2) producing a mixture of the mold base material with a fraction of component (K1) and with a fraction of component (K2a), and also optionally with a fraction of component (K2b). Further described is an aforementioned kit, more particularly for application in the method of the invention. An installation is specified as well for producing an intermediate solution or dispersion, comprising lithium-containing waterglass, for use in producing a molding material mixture or for producing a molding material mixture and a molding therefrom.