The present invention refers to a stable sodium and iron silicate solution that has a weight ratio of SiO.sub.2 to Na.sub.2O from 1.5 to 2.5 and a total percentage of solids, expressed by the sum of SiO.sub.2 and Na.sub.2O, from 20% to 55%. Said solution also has a soluble iron content, expressed by Fe, from 0.1% to 7%, and a water content from 38% to 79.9%. The present invention also refers to the process for preparing said stable solution of sodium and iron silicate, which comprises the steps of: (a) providing a siliceous material containing iron; (b) submitting said siliceous material containing iron to a hydrothermal treatment with caustic soda under high temperature and controlled pressure; and (c) filtering said reacted solution to separate the reacted portion of the hydrothermal treatment from the unreacted portion. Additionally, the present invention refers to the uses of said stable sodium and iron silicate solution.

Disclosed herein are embodiments of a coating composition for use in investment casting. The coating composition embodiments provide a solidified coat that can be as a mold for casting castable materials and that is easily removed from the casted material using water. The coating composition embodiments disclosed herein are reusable and are non-toxic and exhibit high thermal stability.

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.

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.

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.

With excellent heat retention of molten metal and better productivity/work environment, regardless of low-speed or high-speed, the usable die lubricant for die casting will be provided. An aqueous die lubricant for die casting in which a phyllosilicate mineral is dispersed at a concentration of 0.005 wt % or more and less than 5 wt % and has a particle diameter of 0.1 μm or less during the dispersion.

The invention relates to a binder, which contains water glass and further a phosphate or a borate or both. The invention further relates to a method for constructing molds and cores layer by layer, the molds and cores comprising a construction material mixture, which at least comprises a refractory molding base material, and the binder. In order to produce the molds and cores layer by layer in 3-D printing, the refractory molding base material is applied layer by layer and is selectively printed with the binder layer by layer, and consequently a body corresponding to the molds or cores is constructed and the molds or cores are released after the unbonded construction material mixture has been removed.

A method for inorganic binder casting including selecting a shape-forming material based on pre-determined manufacturing and shape characteristics, forming the shape-forming material by printing the shape-forming material using a plurality of additive material printers to form a casting mold, creating a liquid binder solution, the liquid binder solution configured to include at least 51% inorganic binder material by weight, the inorganic binder material having a weight ratio to the liquid binder solution between a range of 1.0 and 3.5, coating the shape-forming material with the liquid binder solution, substantially dehydrating the shape-forming material, pouring a hot liquid metal into the casting mold, and allowing said hot liquid metal to cool to form a molded part.

A method for inorganic binder casting including selecting a shape-forming material based on pre-determined manufacturing and shape characteristics, forming the shape-forming material by printing the shape-forming material using a plurality of additive material printers to form a casting mold, creating a liquid binder solution, the liquid binder solution configured to include at least 51% inorganic binder material by weight, the inorganic binder material having a weight ratio to the liquid binder solution between a range of 1.0 and 3.5, coating the shape-forming material with the liquid binder solution, substantially dehydrating the shape-forming material, pouring a hot liquid metal into the casting mold, and allowing said hot liquid metal to cool to form a molded part.

“Lost” cores for use high pressure die casting, the cores preferably having a water-soluble synthetic ceramic aggregate having an appropriate strength and tolerance for various casting pressures and temperatures, an inorganic binder having sodium silicate, an additive having particulate amorphous silicon dioxide, and a refractory coating, wherein the cores have the capacity to be removed from a casting by dissolution with water.