The subject matter of the invention is mold material mixtures for producing molds or cores for metal casting, consisting of at least one refractory base mold material, a binder and an additive based on factice. The invention also relates to a component system, a method for producing molds and cores using the mold material mixtures or the component system respectively, and to molds and cores produced by said method.

A method of casting an article from a molten metal including: admitting molten metal to a mould formed from a foundry sand comprising a blend of silica sand and a zircon aggregate, the zircon aggregate exhibiting a sharp rise in linear thermal expansion coefficient in a temperature band above 1200 C. and up to 1600 C.; and cooling the mould and molten metal to solidify the molten metal and form a cast article, wherein one or more surfaces of the mould, or of a portion of the mould, in contact with the molten metal are uncoated.

A method of casting an article from a molten metal including: admitting molten metal to a mould formed from a foundry sand comprising a blend of silica sand and a zircon aggregate, the zircon aggregate exhibiting a sharp rise in linear thermal expansion coefficient in a temperature band above 1200 C. and up to 1600 C.; and cooling the mould and molten metal to solidify the molten metal and form a cast article, wherein one or more surfaces of the mould, or of a portion of the mould, in contact with the molten metal are uncoated.

A method of forming a dry molding sand additive may include recovering a non-sand fraction from a foundry waste material and adding the non-sand fraction to a dry molding sand additive formulation to form a dry molding sand additive. Adding the non-sand fraction to the dry molding sand additive formulation may reduce the amount of fresh clay and carbon to produce the dry molding sand additive. A method of forming a molding sand additive may include recovering a waste molding sand additive composition having a clay or carbon content differing from a desired clay and carbon content, recycling the waste molding sand additive as a raw material in production of a fresh molding sand additive, and adjusting the amount of fresh clay or carbon added during production of the fresh molding sand additive to achieve the desired clay and carbon content.

A method of forming a dry molding sand additive may include recovering a non-sand fraction from a foundry waste material and adding the non-sand fraction to a dry molding sand additive formulation to form a dry molding sand additive. Adding the non-sand fraction to the dry molding sand additive formulation may reduce the amount of fresh clay and carbon to produce the dry molding sand additive. A method of forming a molding sand additive may include recovering a waste molding sand additive composition having a clay or carbon content differing from a desired clay and carbon content, recycling the waste molding sand additive as a raw material in production of a fresh molding sand additive, and adjusting the amount of fresh clay or carbon added during production of the fresh molding sand additive to achieve the desired clay and carbon content.

Compositions useful for green sandcasting are discussed, as well as methods of preparing and using such compositions. Binder compositions may comprise a carbonaceous material, an inorganic binding agent, and a high aspect ratio silicate, wherein at least one of the carbonaceous material or the inorganic material in the binder composition may be oxidized. For example, the inorganic binding agent may be oxidized with a ratio of ferrous iron (Fe.sup.2+) to ferric iron (Fe.sup.3+) less than 1.2. or less than 1. Green sand prepared from such binder compositions may exhibit a reduction in emissions during sandcasting.

Compositions useful for green sandcasting are discussed, as well as methods of preparing and using such compositions. Binder compositions may comprise a carbonaceous material, an inorganic binding agent, and a high aspect ratio silicate, wherein at least one of the carbonaceous material or the inorganic material in the binder composition may be oxidized. For example, the inorganic binding agent may be oxidized with a ratio of ferrous iron (Fe.sup.2+) to ferric iron (Fe.sup.3+) less than 1.2. or less than 1. Green sand prepared from such binder compositions may exhibit a reduction in emissions during sandcasting.

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 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 a method of producing an article selected from the group consisting of casting mold, core, feeder and molding compound for production of part of a casting mold, core or feeder, comprising the following steps: (S1) producing or providing in the foundry: a first component (A), comprising a first binder component (b1) of a binder system and an amount of a first mold base material and, spatially separated therefrom, a second component (B), comprising a second binder component (b2) of the binder system and an amount of a second mold base material wherein the first binder component (b1) and the second binder component (b2) are suitable for chemical reaction with one another and for curing of a mixture of the first component (A) and the second component (B), (S2) mixing by contacting the first component (A) and the second component (B) in a particular mass ratio, so as to result in a self-curing molding compound.