Nippon Steel Corporation

Mayumi Okimori

Tomoaki Tanaka

Kensuke Shimomura

Gaku Ogawa

Hiroshi Iwasaki

Hiroaki Morishige

Hironori Takano

Tadashi Imoto

Masaru Sadachika

Nobuyuki Makino

Kenji Abe

A vacuum/reduced pressure refining vessel (,) is connected, by an upstream duct (,) to a dry dust collector (,) that uses a filter (,). The dry dust collector (,) is connected to a reduced pressure evacuating apparatus (,) by a downstream duct (,), and a block valve (,) is provided in the upstream duct (,). At the start of a vacuum/reduced pressure refining treatment, a non-oxidizing gas is injected into the upstream duct at a position that is upstream of the block valve (,) to substantially replace the oxygen in the upstream duct and to hermetically close the upstream duct. After the hermetically closed state has been established in the upstream duct, the block valve (,) is opened and operation of the dry dust collector (,) is started. At the end of the vacuum/reduced pressure refining treatment, the block valve (,) is closed and only the non-oxidizing gas is injected into the upstream duct to return the pressure, and then the upstream duct is opened to atmospheric air, and preferably an open port on the side of the dry dust collector (,) is closed during a waiting period from the end of the vacuum/reduced pressure refining treatment until the start of the next vacuum/reduced pressure refining treatment.

Method for vacuum/reduced-pressure refining and facility for vacuum/reduced-pressure refining

Vacuum refining furnace

Growing community of inventors

Hikari, Japan

Mayumi Okimori