A.l.m.t. Corporation

Sumitomo Electric Industries, Limited

Sumitomo Electric Hardmetal Corp.

Nagoya University

Kazuo Sasaya

Akihiko Ikegaya

Yoshiharu Yamamoto

Takayuki Fudo

Fumiatsu Sato

Syunsuke Yamanaka

Takahisa Iguchi

Akira Nakano

Takuya Okuno

Hideki Moriguchi

Kazuhiro Hirose

Takehiko Hayashi

Hideaki Ito

Takeshi Itakura

A powder containing tungsten carbide has an Fsss particle size of greater than or equal to 0.3 &#x3bc;m and less than or equal to 1.5 &#x3bc;m, and a content rate of the tungsten carbide of greater than or equal to 90% by mass. The powder has a crystallite size (average particle diameter) Y satisfying a relational expression of Y&#x2264;0.1&#xd7;X+0.20 (X: the Fsss particle size of the power containing tungsten carbide).

Powder containing tungsten carbide

Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.

Method for producing sodium tungstate, method for collecting tungsten, apparatus for producing sodium tungstate, and method for producing sodium tungstate aqueous solution

A method for producing an ammonium tungstate aqueous solution includes the steps of: adding sulfuric acid to a solution containing tungstate ions; bringing the solution having the sulfuric acid added therein, into contact with an anion exchange resin; and bringing the anion exchange resin into contact with an aqueous solution containing ammonium ions.

Method for producing ammonium tungstate aqueous solution

There are provided a cemented carbide high in thermal diffusivity and excellent in wear resistance, and a cutting tool including a base material formed of this cemented carbide. The cemented carbide is a WC based cemented carbide in which a hard phase mainly constituted of WC grains is bound by a binder phase mainly constituted of Co, and is used for a cutting tool. The binder phase is substantially constituted of Co, or Co and Ni. A total content of Co and Ni is not less than 4.5 mass % and not more than 15 mass %. In this cemented carbide, the WC grains have an average diameter of not less than 0.4 &#x3bc;m and not more than 4 &#x3bc;m.

Cemented carbide and cutting tool using same

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Toyama, Japan

Kazuo Sasaya