Dowa Mining Co., Ltd.

Takashi Ohgami

Kishio Tayama

Hiroshi Miura

Hidekazu Kato

Takeharu Yamamura

Kanichi Okuda

A high purity silver wire for use in recording, acoustic or image transmission applications. The high purity silver wire is made of high purity silver containing sulfur, iron, copper, palladium, gold and lead impurities in an amount such that no one of the sulfur, iron, copper, palladium, gold and lead impurities individually exceeds 0.5 ppmw, and wherein all other impurities are present in a total amount of less than 1 ppmw.

High-purity silver wires for use in recording, acoustic or image transmission applications

In a process for separating impurities from a raw gallium material containing impurities, a process for refining gallium comprising progressively solidifying a raw gallium material provided in a liquid state inside a vessel while applying stirring, such that the diameter of the tubular solidification boundary gradually advances from the inner wall plane of the vessel towards the center of the vessel to reduce the diameter of the tubular solidification boundary, and separating the liquid phase remaining in the central portion of the vessel from the solidified phase before the entire raw material inside the vessel is solidified. The process above is repeated as required by using, as the raw gallium material, the solidified phase from which the liquid phase is separated. A metallic gallium favorably used for the preparation of a compound semiconductor can be obtained by analyzing the impurity concentration of the impurity-concentrated Ga separated from the solidified layer.

High purity gallium for preparation of compound semiconductor, and method and apparatus for purifying the same

An apparatus for producing a high-purity silver material. The apparatus includes an electric furnace. The electric furnace has an outer cylinder which encloses an inner cylinder. The outer cylinder is capable of being evacuated with a vacuum pump. A recovery mold is disposed within the inner cylinder. An aspiration table is connected to a central portion of the recovery mold. A feed crucible is disposed above the recovery mold and is connected to the aspiration table. A cooling trap is disposed below the recovery mold. A water-cooling flange is disposed below the cooling mold.

Apparatus for producing high-purity silver materials

A process for producing a high-purity silver material comprising placing a silver feed in a crucible disposed in a furnace comprising an inner cylinder which encloses the crucible and an outer cylinder which encloses the inner cylinder; heating the silver feed at a temperature not lower than 1065&deg; C. and at a pressure not higher than 0.1 Pa such that the silver evaporates and condenses on the ceiling of the inner cylinder to yield silver particles; and collecting silver particles in a recovery mold disposed beneath the crucible and within the inner cylinder, such that gold, copper and other impurities having a lower vapor pressure than silver remain within the crucible, whereas sulfur, sodium and the other impurities having a higher vapor pressure than silver are withdrawn by a vacuum pump and are then introduced into a cooling trap disposed beneath the recovery mold, such that the higher vapor pressure impurities are solidified in the cooling trap.

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Tokyo, Japan

Takashi Ohgami