Abstract: Described is a method of preparing a particulate refractory composition for use in the manufacture of foundry moulds and cores from spent foundry moulds or cores formed of refractory material and a binder containing water glass, the method comprising the following steps: providing broken material from spent foundry moulds or cores or preparing broken material from spent foundry moulds or cores, wherein the broken material comprises particles and/or aggregates of particles of refractory material having hardened water glass binder on their surface, mixing the broken material with particulate amorphous oxide comprising silicon dioxide in an amount of 85% by weight or more, based on the total amount of the particulate amorphous oxide, to give a mixture and subjecting the mixture to a heat treatment at a temperature of 400° C. or higher. Also described are a corresponding use, a reclamation mixture, and a method of making a foundry mould or core.

Abstract: Described is a method of preparing a particulate refractory composition for use in the manufacture of foundry moulds and cores from spent foundry moulds or cores formed of refractory material and a binder containing water glass, the method comprising the following steps: providing broken material from spent foundry moulds or cores or preparing broken material from spent foundry moulds or cores, wherein the broken material comprises particles and/or aggregates of particles of refractory material having hardened water glass binder on their surface, mixing the broken material with particulate amorphous oxide comprising silicon dioxide in an amount of 85% by weight or more, based on the total amount of the particulate amorphous oxide, to give a mixture and subjecting the mixture to a heat treatment at a temperature of 400° C. or higher. Also described are a corresponding use, a reclamation mixture, and a method of making a foundry mould or core.

Abstract: 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.

Abstract: 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.

Abstract: A description is given of a two-component binder system for use in the polyurethane cold box process, a mixture for curing by contacting with a tertiary amine, a method for producing a feeder, a foundry mold or a foundry core, and also feeders, foundry molds and foundry cores producible by this method, and the use of a two-component binder system of the invention or of a mixture of the invention for binding a mold raw material or a mixture of mold raw materials in the polyurethane cold box process.

Abstract: An arrangement for use in the production of a separable casting mold, preferably of a vertically separable casting mold is disclosed. The arrangement can include (i) a mold plate and/or a mold pattern, (ii) a feeder system having a feeder element and having a feeder insert, wherein feeder element and feeder insert delimit a feeder cavity for receiving liquid metal. The arrangement also includes one or more tipping prevention elements which are designed to counteract tipping of the feeder system out of the opening axis about the first end of the feeder element when, in the event of the feeder system being acted on with a force acting parallel to the opening axis and in the direction of the first end, the side wall deforms and the spacing between the first and second ends is reduced, wherein the one or more tipping prevention element(s) are/is spaced apart from the opening axis.

Abstract: This invention relates to a resin preparable by reaction of a phenol/formaldehyde novolak with tetraethyl orthosilicate in a mass ratio above 28:1, wherein the phenol of the phenol/formaldehyde novolak is substituted or unsubstituted hydroxybenzene or a mixture of two or more such phenols, and to a particulate material coated with said resin. Said particles can be used e.g. in the shell molding process for the production of shell molds and shell cores; and as proppants for use in the hydraulic fracturing process.

Abstract: This invention relates to a resin preparable by reaction of a phenol/formaldehyde novolak with tetraethyl orthosilicate in a mass ratio above 28:1, wherein the phenol of the phenol/formaldehyde novolak is substituted or unsubstituted hydroxybenzene or a mixture of two or more such phenols, and to a particulate material coated with said resin. Said particles can be used e.g. in the shell molding process for the production of shell molds and shell cores; and as proppants for use in the hydraulic fracturing process.