Provided is a refractory aggregate that is for casting sand and that comprises spherical refractory sintered particles artificially produced by a sintering method, and that can improve the fluidity of the casting sand and can achieve excellent mold strength. This refractory aggregate is for casting sand, comprises spherical refractory sintered particles artificially produced by a sintering method, is configured to have a roundness of at least 0.70 and an average particle size of 0.01-1.00 mm, and is configured such that the total volume of pores having a pore size of 2-10 μm as measured with a mercury intrusion porosimeter is in the range of 0.20-0.50 mL/g, and the amount of fine powder is additionally mixed such that the turbidity as measured by turbidimetry is at most 3000 NTU.
Provided is a refractory aggregate that is for casting sand and that comprises spherical refractory sintered particles artificially produced by a sintering method, and that can improve the fluidity of the casting sand and can achieve excellent mold strength. This refractory aggregate is for casting sand, comprises spherical refractory sintered particles artificially produced by a sintering method, is configured to have a roundness of at least 0.70 and an average particle size of 0.01-1.00 mm, and is configured such that the total volume of pores having a pore size of 2-10 μm as measured with a mercury intrusion porosimeter is in the range of 0.20-0.50 mL/g, and the amount of fine powder is additionally mixed such that the turbidity as measured by turbidimetry is at most 3000 NTU.
B22C 1/00 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules
B33Y 80/00 - Produits obtenus par fabrication additive
B33Y 70/00 - Matériaux spécialement adaptés à la fabrication additive
Provided is an effective method for reproducing molding sand that has been used in the making of a mold using an inorganic binder containing a liquid glass as the main component thereof from the mold that has been casted. In order to reproduce molding sand comprising artificial spherical refractory particles from a mold that is made using the molding sand and an inorganic binder containing a liquid glass as the main component thereof, the following steps are employed: a step of crushing the mold that has been used and simultaneously separating and removing a fine powder; a crushing/sizing step of sizing the ground product to obtain specific sized sand; a roasting step of subjecting the crushed/sized sand thus produced to a roasting treatment to cause the crystallization of a liquid glass component adhered to the surface of the sand; and a polishing step of mechanically polishing the crushed/sized sand that has been subjected to the roasting treatment to separate the crystallized liquid glass component on the surface of the sand, then collecting the crystallized liquid glass component thus separated using a dust collector and then removing the separated crystallized liquid glass component.
B22C 1/00 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules
B22C 5/00 - Machines ou dispositifs spécialement conçus pour la préparation ou la manutention des matériaux à mouler, dans la mesure où ils sont spécialement adaptés à cette fin
4.
METHOD FOR REGENERATING FLOWING MEDIUM IN FLUIDIZED BED FURNACE
B07B 4/02 - Séparation des solides, obtenue en soumettant leur mélange à des courants de gaz pendant que le mélange tombe
F23G 5/30 - Procédés ou appareils, p. ex. incinérateurs, spécialement adaptés à la combustion de déchets ou de combustibles pauvres avec combustion dans un lit fluidisé
B01J 8/24 - Procédés chimiques ou physiques en général, conduits en présence de fluides et de particules solidesAppareillage pour de tels procédés les particules étant fluidisées selon la technique du "lit fluidisé"
Provided are: a useful bed medium for a fluidized bed with good fluidity, the bed medium being usable in a fluidized bed furnace using biomass material and coal material as fuel; and a useful bed medium for a fluidized bed with good durability, the bed medium not easily forming an agglomerate of its particles, and being resistant to collapsing. The bed medium for a fluidized bed in a fluidized bed furnace for combusting or gasifying the fuel is formed of artificially-produced spherical refractory particles containing not less than 40% by weight of Al2O3 and not more than 60% by weight of SiO2 and having an apparent porosity of not more than 5%, and a ratio by weight of agglomerated particles in the bed medium is not more than 20% after three heat treatment tests on the bed medium at 900° C. for 2 hours under coexistence with the fuel.
F23C 10/01 - Appareils dans lesquels la combustion a lieu dans un lit fluidisé de combustible ou d'autres particules dans un lit fluidisé de particules catalytiques
F23G 5/30 - Procédés ou appareils, p. ex. incinérateurs, spécialement adaptés à la combustion de déchets ou de combustibles pauvres avec combustion dans un lit fluidisé
6.
Porous fired granulated body and method for manufacturing the same
A porous fired granulated body is formed by consolidating numerous alumina particles to each other while letting mainly interconnected pores remain in network form across an entire cross section of a granulated body particle. The pores have an inner diameter controlled by a droplet diameter of a pore forming agent and have numerous precipitated alumina crystals formed on inner surfaces thereof. Manufacture is performed by spraying the pore forming agent (emulsion) onto a raw material to form a coating layer of the pore forming agent on a surface of the raw material particle and controlling the inner diameter of the pores. A porous fired granulated body of alumina having a high specific surface area and having higher strength for the same specific surface area can thus be provided by a simple manufacturing method.
The present invention provides a useful fluidized medium for a fluidized bed, the fluidized medium having excellent fluidity and being suitable for use as a fluidized medium in a fluidized bed furnace that uses biomass material and coal as fuel. The present invention also provides a useful fluidized medium for a fluidized bed, the fluidized medium having excellent durability, not easily forming an aggregate of particles, and not being easily destroyed. Used as the fluidized medium for a fluidized bed in a fluidized bed furnace that is used to combust or gasify fuel comprising biomass material and/or coal is a fluidized medium that comprises artificially produced spherical refractory particles having a chemical composition comprising 40 wt% or more of Al2O3 and 60 wt% or less of SiO2, having an apparent porosity of 5% or less, and having a weight ratio of 20% or less of aggregated particles after a heating treatment test has been repeated three times at 900ºC×2 hours in coexistence with the fuel.
F23G 5/30 - Procédés ou appareils, p. ex. incinérateurs, spécialement adaptés à la combustion de déchets ou de combustibles pauvres avec combustion dans un lit fluidisé
F23C 10/18 - Appareils dans lesquels la combustion a lieu dans un lit fluidisé de combustible ou d'autres particules Parties constitutivesAccessoires
F23G 5/027 - Procédés ou appareils, p. ex. incinérateurs, spécialement adaptés à la combustion de déchets ou de combustibles pauvres comportant un traitement préalable par pyrolyse ou par gazéification
Porous burned granules produced by consolidating countless alumina particles so that mainly interconnected voids remain in a network state throughout the section of each granule particle (11). The voids (13) have diameters which have been regulated by the droplet diameter of a void-forming agent, and the inner surface has countless alumina crystals (15) deposited thereon. The void-forming agent (emulsion) is sprayed over a raw material to form a coating layer of the void-forming agent on the surface of the particles of the raw material, and the porous burned granules are produced therefrom while regulating the diameters of the voids. With such simple production process, it is possible to provide porous burned alumina granules having a large specific surface area and having even higher strength than ones having the same specific surface area.
To provide a ceramic aggregate for refractories, which enables a refractory to exhibit excellent spalling resistance. This ceramic aggregate for refractories is configured to have (a) a chemical composition that contains 50% by weight or more of Al2O3, 50% by weight or less of SiO2 and 10% by weight or less of impurities, (b) a columnar shape having a length in the major axis direction (L) of 100 mm or less, a length in the minor axis direction (D) of 3 mm or more and an aspect ratio (L/D) of 1.5 or more, and (c) a surface roughness (Ra) of 10 μm or less and a maximum height (Ry) of 100 μm or less.
Providing a method of modifying refractory particles used to produce a casting mold by using a furan resin as a binder, so as to effectively improve a strength of the casting mold and to reduce a required amount of the binder. An artificial aggregate which is artificially produced and which has an apparent porosity of not more than 5% is used as the refractory particles, and the artificial aggregate is subjected to a heat treatment at a temperature of 400-1500° C. for not shorter than one hour in a heating atmosphere having an oxygen concentration of not higher than 15%.
B22C 1/22 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules caractérisées par l'emploi des agents liantsMélange d'agents liants d'agents organiques de résines naturelles ou synthétiques
B22C 9/02 - Moules en sable ou moules analogues pour pièces coulées
C04B 35/626 - Préparation ou traitement des poudres individuellement ou par fournées
B22C 5/00 - Machines ou dispositifs spécialement conçus pour la préparation ou la manutention des matériaux à mouler, dans la mesure où ils sont spécialement adaptés à cette fin
C04B 35/107 - Réfractaires obtenus par coulée par fusion
The present invention addresses the problem of modifying refractory particles, which are to be molded through use of a furan resin as a binder, and thereby attaining an effective improvement in the strength of a mold and a reduction in binder consumption. This method for modifying refractory molding particles comprises: using, as refractory particles which are to be molded through use of a furan resin as a binder, an artificial aggregate which has been produced artificially and which has an apparent porosity of 5% or less; and heat-treating the artificial aggregate in a heating atmosphere having an oxygen concentration of 15% or less at a temperature of 400 to 1500ºC for one or more hours.
B22C 1/00 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules
B22C 1/22 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules caractérisées par l'emploi des agents liantsMélange d'agents liants d'agents organiques de résines naturelles ou synthétiques
B22C 5/00 - Machines ou dispositifs spécialement conçus pour la préparation ou la manutention des matériaux à mouler, dans la mesure où ils sont spécialement adaptés à cette fin
