Electric furnace and method for melting and reducing iron oxide-containing iron raw material

Patent metadata

Field	Value
Publication number	US-2021190427-A1
Application number	US-201816757276-A
Country	US
Kind code	A1
Filing date	Oct 17, 2018
Priority date	Oct 23, 2017
Publication date	Jun 24, 2021
Grant date	—

Abstract

This electric furnace includes one or more upper electrodes, one or more bottom-blowing tuyeres, a mechanical stirrer equipped with an impeller, and a charging device which injects an iron oxide-containing iron raw material.

First claim

1 . An electric furnace comprising:
one or more upper electrodes; one or more bottom-blowing tuyeres; a mechanical stirrer equipped with an impeller; and a charging device which injects an iron oxide-containing iron raw material.

2 . The electric furnace according to claim 1 , comprising:
three or more of the bottom-blowing tuyeres; and a plurality of the upper electrodes, wherein, when a straight line orthogonal to a shortest line segment of individual line segments connecting centers of the upper electrodes and a center of the impeller is drawn at a point closer to the impeller between two points that equally divide the shortest line segment into three parts in a plan view, centers of at least three bottom-blowing tuyeres among the respective bottom-blowing tuyeres are present closer to the respective upper electrodes than the orthogonal straight line.

3 . The electric furnace according to claim 2 ,
wherein, in the plan view, centers of all of the respective upper electrodes and a raw material injection opening of the charging device is present inside a polygonal shape connecting the respective centers of the three or more bottom-blowing tuyeres present closer to the respective upper electrodes than the orthogonal straight line.

4 . A method for melting and reducing an iron oxide-containing iron raw material in which the electric furnace according to claim 1 is used, the method comprising:
when the iron oxide-containing iron raw material having an iron metallization percentage of 45% or more and 95% or less is charged from the charging device and melted and reduced in the electric furnace in which molten metal is present, immersing and rotating the impeller of the mechanical stirrer in the molten metal, thereby stirring slag present on a surface of the molten metal and the molten metal.

5 . A method for melting and reducing an iron oxide-containing iron raw material in which the electric furnace according to claim 2 is used, the method comprising:
when the iron oxide-containing iron raw material having an iron metallization percentage of 45% or more and 95% or less is charged from the charging device and melted and reduced in the electric furnace in which molten metal is present, immersing and rotating the impeller of the mechanical stirrer in the molten metal, thereby stirring slag present on a surface of the molten metal and the molten metal.

6 . A method for melting and reducing an iron oxide-containing iron raw material in which the electric furnace according to claim 3 is used, the method comprising:
when the iron oxide-containing iron raw material having an iron metallization percentage of 45% or more and 95% or less is charged from the charging device and melted and reduced in the electric furnace in which molten metal is present, immersing and rotating the impeller of the mechanical stirrer in the molten metal, thereby stirring slag present on a surface of the molten metal and the molten metal.

Assignees

• Nippon Steel Corp

Inventors

• Taguchi Takahiro
• Yamazaki Tsuyoshi
• Kasahara Shuhei

Classifications

• Y02P10/20

  Recycling · CPC title

• C21C5/52

  Manufacture of steel in electric furnaces {(C21C5/005 takes precedence)} · CPC title

• F27B3/085 Primary

  Arc furnaces · CPC title

• F27D11/08

  Heating by electric discharge, e.g. arc discharge · CPC title

• F27D27/00 Primary

  Stirring devices for molten material (charging or discharging liquid or molten material F27D3/14) · CPC title