Showa Denko K.k.

Showa Denko Kabushiki Kaisha

Showda Denko K.k.

Shinichiro Tomikawa

Jun Tanaka

So Miyaishi

Hirokazu Miyazawa

Takeshi Iemura

Satoshi Yamaoka

Provided are a method for producing an alumina sintered compact satisfying the following (1) and (2), which comprises mixing and sintering an ilmenite powder and an alumina powder; the alumina sintered compact obtained according to the production method; and an abrasive grain and a grain stone.

Method for producing alumina sintered body, alumina sintered body, abrasive grains, and grindstone

Provided are an alumina sintered compact containing a titanium compound and an iron compound, wherein the total amount of the TiO-equivalent content of the titanium compound, the FeO-equivalent content of the iron compound and the alumina content is at least 98% by mass, the total amount of the TiO-equivalent content of the titanium compound and the FeO-equivalent content of the iron compound is from 5 to 13% by mass, and the ratio by mass of the TiO-equivalent content of the titanium compound to the FeO-equivalent content of the iron compound (TiO/FeO) is from 0.85/1.15 to 1.15/0.85; and an abrasive grain and a grain stone using the alumina sintered compact.

Alumina sintered body, abrasive grains, and grindstone

Provided are an alumina sintered compact containing a titanium compound and an iron compound, wherein FeTiAlOgrains exist in the grain boundary of the alumina grains and the mean grain size of the FeTiAlOgrains is from 3.4 to 7.0 &#x3bc;m; and an abrasive grain and a grain stone using the alumina sintered compact.

A roundish fused alumina particles having a mean particle size of 5 to 4,000 &#x3bc;m and a roundness of 0.85 or more, and a producing method thereof are provided. The method comprises removing edges of fused alumina particles by making the fused alumina particles collide with each other.

Roundish fused alumina particles, production process thereof, and resin composition containing the particles

An ultrafine mixed-crystal oxide, wherein the oxide has a change in absorbance of about 5 (/hr) or less when measured in such a manner that said oxide is dispersed at a concentration of 0.067% in a solvent of a 98% glycerin in which Sunset Yellow is dissolved at a concentration of 0.02%, thereby preparing a dispersion, and the dispersion is irradiated with a BLB lamp (ultraviolet light) with an intensity of 1.65 mW/cmto obtain said change in absorbance (&#x394;OD) at 490 nm.

Ultrafine mixed-crystal oxide, production process and use thereof

The invention provides a dry grinding system including grinding means for dry-grinding a material to be ground; first classification means for classifying a ground product obtained through the grinding means, into fine powder having a relatively small average particle size and coarse powder having a relatively large average particle size; second classification means for further classifying the coarse powder obtained through the first classification means, into find powder having a relatively small average particle size and coarse powder having a relatively large average particle size; and returning means for returning to the grinding means the coarse powder obtained through the second classification means. The invention enables production of a powder product having a desired average particle size at high efficiency.

Dry grinding system and dry grinding method

The invention provides a dry grinding system including grinding means for dry-grinding a material to be ground; first classification means for classifying a ground product obtained through the grinding means, into fine powder having a relatively small average particle size and coarse powder having a relatively large average particle size; second classification means for further classifying the coarse powder obtained through the first classification means, into fine powder having a relatively small average particle size and coarse powder having a relatively large average particle size; and returning means for returning to the grinding means the coarse powder obtained through the second classification means. The invention enables production of a powder product having a desired average particle size at high efficiency.

A process for producing an ultrafine mixed-crystal oxide characterized by producing an ultrafine mixed crystal oxide comprising primary particles in a mixed crystal state with a BET specific surface area of 10 to 200 m/g, comprising the step of subjecting a halogenated metal to high temperature oxidation with an oxidizing gas to produce a metal oxide by a vapor phase production method, wherein said halogenated metal is in the form of a mixed gas (a mixed halogenated metal gas) comprising at least two compounds having a different metal elements selected from the group consisting of chlorides, bromides, and iodides of titanium, silicon, and aluminum, and said mixed halogenated metal gas and said oxidizing gas are independently preheated to 500&#xb0; C. or more prior to a reaction, a ultrafine mixed crystal oxide obtained by the process, and use of the oxide.

The present invention provides a process for producing ultrafine particulate complex oxide containing titanium oxide, including vapor-phase producing a complex oxide containing titanium oxide having a BET specific surface area of about 5 to about 200 m /g, where a starting material gas containing titanium tetrachloride and an oxidizing gas are preheated to about 700&deg; C. or more, and are reacted with a solution or a slurry of a salt containing a metallic element. The present invention also provides an ultrafine particulate complex oxide containing titanium oxide obtained by the process, and use of the oxide.

Ultrafine particulate complex oxide containing titanium oxide

A process for producing an ultrafine mixed-crystal oxide characterized by producing an ultrafine mixed crystal oxide comprising primary particles in a mixed crystal state with a BET specific surface area of 10 to 200 m /g, comprising the step of subjecting a halogenated metal to high temperature oxidation with an oxidizing gas to produce a metal oxide by a vapor phase production method, wherein said halogenated metal is in the form of a mixed gas (a mixed halogenated metal gas) comprising at least two compounds having a different metal elements selected from the group consisting of chlorides, bromides, and iodides of titanium, silicon, and aluminum, and said mixed halogenated metal gas and said oxidizing gas are independently preheated to 500&deg; C. or more prior to a reaction, a ultrafine mixed crystal oxide obtained by the process, and use of the oxide.

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Shiojiri, Japan

Shinichiro Tomikawa