Kawasaki Steel Corporation

Nippon Sheet Glass Company, Limited

Kawasaki Steel Corporation, Technical Research Division

Fukuo Aratani

Yasuhiko Sakaguchi

Noriyoshi Yuge

Hiroyuki Baba

Naomichi Nakamura

Yoshiei Kato

Kazuhiro Hanazawa

Tetsuro Kawahara

Kazuhiro Uchino

Mitsugi Yoshiyagawa

Kunio Miyata

Masamichi Abe

Tsuyoshi Fukutake

Masato Ishizaki

Kyojiro Kaneko

Process and apparatus for refining silicon by treatment in a graphite vessel with irradiation with an electron beam while removing impurity elements by evaporation. A single graphite vessel is used, or plural graphite vessels are arranged in sequence. During treatment in successive graphite vessels, molten silicon is poured in succession from one vessel to another. Use of graphite vessels improves heat efficiency, prevents contamination and produces refined silicon containing very low contents of impurities.

Process and apparatus for refining silicon

Process and apparatus for manufacturing polycrystalline silicon, and

A process for producing high-purity silicon for solar cells continuously directly from inexpensive silicon containing a comparatively large amount of impurities. This process comprises melting continuously supplied raw material silicon in a bottomless crucible placed in an induction coil, while blowing a hot plasma gas incorporated with an oxygen-containing substance on the surface of the melt for purification, and continuously discharging the solidified silicon downward from said bottomless crucible, with at least an axial part of said bottomless crucible being divided into a plurality of electrically conductive pieces spaced circumferentially.

Production of high-purity silicon ingot

High-yield preparation of high-purity metallic silicon at is performed by subjecting a stream of oxides of silicon (e.g. in an aerosol) to reaction heat in the presence of a mixture of a material of the group including silicon carbide and silicon dioxide; and a material of the group including carbon and carbon-containing substance. Preferably, silicon oxide produced by the reaction is scavenged from exhaust gas leaving the reaction chamber, re-condensed, and returned to the reaction chamber.

Method and apparatus for preparing high-purity metallic silicon

Disclosed herein are a method and apparatus for purifying silicon, which are suitable for economical and mass production of high-purity silicon for solar cells from regular-grade silicon containing boron and carbon in large quantities. The method comprises directing a plasma jet stream of an inert gas toward the surface of molten silicon held in a container lined with silica or a silica-based refractory. For improved purification, the inert gas as the plasma gas is mixed with 0.1-10 vol % steam and/or less than 1 g of silica powder per liter of the inert gas at normal state. Alternatively, the container may have a bottom opening and is provided with an electrode having a cooling means underneath the bottom of the container, with the electrode and the cathode of the plasma torch connected to a power source for plasma generation, so that the plasma jet and electron beam are directed toward the surface of molten silicon.

Method and apparatus for purifying silicon

Method for producing high-purity metallic silicon and apparatus therefor

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Chiba, Japan

Fukuo Aratani