Mitsubishi Aluminum Company, Ltd.

Stella Chemifa Kabushiki Kaisha

Hashimoto Chemical Co., Ltd.

Other

Hiroto Izumi

Hirohisa Kikuyama

Tadahiro Ohmi

Matagoro Maeno

Yutaka Mikasa

Yoshinori Nakagawa

Kazuo Chiba

Hideo Kume

Shinji Hashiguchi

Hirofumi Yazaki

Kazuhito Yamane

Masahide Waki

Kenji Aoki

Masatsugu Kawawaki

Yuko Murakami

Masayuki Miyashita

Takanobu Kujime

Fumiaki Aono

Akiyoshi Kosuge

Toshiharu Tabata

An object of the present invention is to provide a method for purifying a highly pure niobium compound and/or tantalum compound, the method enabling the purification of a highly pure niobium compound and tantalum compound in a simplified manner at a low cost. The object is met by providing a method comprising adding an organic solvent to an aqueous solution containing a niobium compound and/or tantalum compound together with impurities, and then performing extraction via the solution. A niobium compound and/or tantalum compound dissolved in a solution is allowed to precipitate, and said aqueous solution is obtained by dissolving the precipitate in water.

Purification method for producing high purity niobium compound and/or tantalum compound

The present invention provides a method enabling the high purification of a niobium compound and/or tantalum compound in a simplified manner at a low cost. This is accomplished by providing a method enabling the high purification of a niobium compound and/or tantalum compound comprising the steps of preparing a solution containing niobium and/or tantalum, allowing a precipitate comprising niobium and/or tantalum to develop, separating the precipitate by filtration from the filtrate, converting the precipitate to a liquid melt or taking the filtrate, and separating a niobium compound from a tantalum compound or vice versa by utilizing the difference in solubility to the solvent between the niobium compound and the tantalum compound.

A stainless steel with a passive state fluorinated film formed thereon, which is easy to construct and does not produce particles even when it is welded, and a device using the same. The stainless steel does not cause leakage even when said film is formed on a sealing surface of a joint and a valve seat surface. The stainless steel is characterized in that at least a part of the surface coated with a passive state fluorinated film not thicker than 190&angst; consisting of a metal fluoride as a main component.

Stainless steel having passive fluoride film formed thereon and equipment manufactured therefrom

A hydrogen containing material comprises a first compound including hydrogen containing material and fluoride, and a second compound including a metal which becomes highly reactive with hydrogen when the metal becomes a compound including fluorine, and a compound including fluorine. The first compound and the second compound are integrally formed into a one-piece layer on the surface of the hydrogen containing material. The metal which becomes highly reactive with hydrogen when the metal becomes a compound including fluorine is at least one metal selected from a rare earth metal, rare earth alloy, Fe, Al, Mg, Ca, Mn, Zn, Zr, Li, or alloys comprising these elements.

Highly activated hydrogen containing material and method for producing the material

A metal material characterized in that the material comprises a substrate metal, a film comprising a nickel fluoride layer and formed on the substrate metal, and a film comprising a carbon layer and formed on the film.

Metal material formed with fluorocarbon film, process for preparing the

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Izumiootsu, Japan

Hiroto Izumi