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 provides A magnesium oxide whisker in-situ formed MA spinel-reinforced magnesium oxide-based ceramic foam filter and a method for preparing the same. The method comprising: 1) preparing a ceramic slurry having a solid content of 60%-70% by dosing 15%-25% by mass of a nanometer alumina sol, 0.8%-1.5% by mass of a rheological agent, and the balance magnesium oxide ceramic powder comprising magnesium oxide whiskers, and then adding deionized water and ball milling to mix until uniform, and then vacuum degassing the mixture; 2) soaking a polyurethane foam template into the ceramic slurry, squeezing by a roller press the polyurethane foam template to remove redundant slurry therein to make a biscuit, and drying the biscuit by heating it to 80° C.-1200° C.; 3) putting the dried biscuit into a sintering furnace, elevating the temperature to 1400° C.-1600° C. and performing a high temperature sintering, cooling to the room temperature with the furnace to obtain the magnesium oxide-based ceramic foam filter.

A method for producing a sand mold includes mixing artificial sand with a furan resin composition including a furan resin precursor, preparing molding sand having the artificial sand and a surface-modified layer containing a resin cured product covering the artificial sand and including a curing agent attached to the surface-modified layer by mixing the curing agent including xylene sulfonic acid with the artificial sand with which the furan resin composition is mixed, and curing the furan resin composition, after mixing the artificial sand with the furan resin composition, and curing an added portion of the binder in the molding sand by adding the binder to the molding sand. In the step of curing the added portion of the binder, the curing agent for curing the furan resin composition is used also as a curing agent for curing the binder.

A spiral-orifice ceramic filter for metal casting, including spiral channels and two drain openings, where the spiral channels are distributed in a ceramic substrate in a staggered manner. By adoption of the spiral channel structure, molten metal may rotate to generate a centrifugal force while flowing forwards so as to promote separation of inclusions. The spiral-orifice ceramic filter for metal casting includes the following components: 90-95 wt % of MgO, 4-8 wt % of SiO.sub.2 and 2-4 wt % of ZrO.sub.2. Therefore, the spiral-orifice ceramic filter for metal casting has high strength under normal temperature and optional thermal impact resistance under high temperature, and may tolerate the impact of molten metal at 1700° C. or higher without break. The ceramic substrate and the spiral channel are superficially coated with one layer of functional oxide prepared from CaO.2Al.sub.2O.sub.3, CaO.6Al.sub.2O.sub.3, Al.sub.2O.sub.3, TiO.sub.2, or Re.sub.2O.sub.3.

A method of preparing a unique foundry premix composition that has a low bulk density of 30-45 lbs/ft.sup.3 and contains fine particles with an average particle size of 85-100 μm is described. The unique foundry premix composition is produced by using specially designed assemblies of mechanical equipment with improved efficiency so that the premix can be prepared at a site closer to a foundry. As a result, increase in premix density caused by handling and shipping across a long distance from a traditional premix manufacturing facility to a foundry can be suppressed; transportation cost can be saved; and safety would be of less concern. The use of the foundry premix composition to prepare a sand molding medium for casting molded articles is also described.

A sand additive for use in a “no bake” foundry mix composition having a polyurethane-based binder system reduces the amount of smoke emitted when molds and cores formed from the composition are exposed to molten metal, as compared to when the sand additive is not used. The sand additive comprises yellow iron oxide having the chemical formula Fe(OH).sub.3. It can also comprise at least one of red iron oxide, black iron oxide and wüstite. In such cases, the yellow iron oxide accounts for about 10 to about 40 weight percent of the combined weight of the yellow iron oxide, red iron oxide, black iron oxide and wüstite, and preferably, about 20 to about 30 weight percent of the combined weight of the yellow iron oxide, red iron oxide, black iron oxide and wüstite.

Disclosed is a method for manufacturing a hydraulic binder including a calcium aluminate, which involves: a) providing a composition including a lime C source compound and an alumina source compound, the composition including at most 95% lime C and alumina, and at least 23% alumina, by weight relative to the total weight of dry matter of the composition; b) placing the composition provided in step a) in a moisture-saturated environment, at a hydration temperature of between 40° C. and 150° C., so as to precipitate hydrated phases containing at least one aluminium oxide combined with a calcium oxide and with water; and c) subjecting the precipitates obtained in step b) to a baking temperature of between 200° C. and 1300° C., for at least 15 minutes.

A heat insulating plate (1), preferably a covering plate (5a;b), especially for thermal isolation of molten metal, especially of molten steel, in a metallurgical vessel (6), wherein the plate (3) includes a binding agent matrix (2) of at least one, set, temporary, organic binding material and aggregate grains (3) with and/or of biogenic silicic acid, preferably with and/or of rice husk ash, which grains (3) are incorporated into the binding agent matrix (2), and to a method for production of the plate (1) and its use.

A method of preparing a unique foundry premix composition that has a low bulk density of 30-45 lbs/ft.sup.3 and contains fine particles with an average particle size of 85-100 μm is described. The unique foundry premix composition is produced by using specially designed assemblies of mechanical equipment with improved efficiency so that the premix can be prepared at a site closer to a foundry. As a result, increase in premix density caused by handling and shipping across a long distance from a traditional premix manufacturing facility to a foundry can be suppressed; transportation cost can be saved; and safety would be of less concern. The use of the foundry premix composition to prepare a sand molding medium for casting molded articles is also described.

A molding material in a powder-fixing lamination method includes an aggregate and a powdery precursor of a binder that binds the aggregate mutually. The aggregate is a casting sand, and the powdery precursor contains a hardening component and a hardening accelerating component. A molded product is manufactured using the molding material.