Method for producing molten iron using electric furnace

Patent metadata

Field	Value
Publication number	US-2024035102-A1
Application number	US-202017630025-A
Country	US
Kind code	A1
Filing date	Jun 22, 2020
Priority date	Sep 10, 2019
Publication date	Feb 1, 2024
Grant date	—

Abstract

An electric furnace with energy utilization efficiency at a low cost. In an electric furnace, a preheating chamber 2 with a melting chamber 1 is used to preheat iron scrap x, an exhaust gas generated in melting chamber 1 is passed through preheating chamber 2 filled with the iron scrap x to preheat the iron scrap x, the iron scrap x descends in the preheating chamber 2 to be supplied into melting chamber 1, and the iron scrap x is melted to obtain molten iron m. The iron scrap x is charged into preheating chamber 2 so that bulk density is not less than 0.50 t/m3 and less than 1.00 t/m3 and an iron scrap filling ratio HSC/HSF in the preheating chamber 2 is 0.5 to 0.8. A carbonaceous material is used for melting the iron scrap x, and oxygen and the carbonaceous material are blown into the melting chamber.

First claim

1 . A method for producing molten iron using an electric furnace comprising a melting chamber ( 1 ) for melting iron scrap by arc heating and a shaft-type preheating chamber ( 2 ) provided on and continuously with the melting chamber ( 1 ) and used to preheat the iron scrap, in which the iron scrap is sequentially charged into the preheating chamber ( 2 ) so that the preheating chamber ( 2 ) is filled with the iron scrap, an exhaust gas generated in the melting chamber ( 1 ) is passed through the preheating chamber ( 2 ) filled with the iron scrap so as to preheat the iron scrap, the iron scrap thus preheated is sequentially caused to descend in the preheating chamber ( 2 ) so as to be supplied into the melting chamber ( 1 ), and the iron scrap is melted in the melting chamber ( 1 ) to obtain molten iron,
wherein the iron scrap is charged into the preheating chamber ( 2 ) so that an apparent bulk density (P) of the iron scrap filled in the preheating chamber ( 2 ) is not less than 0.50 t/m 3 and less than 1.00 t/m 3 and an iron scrap filling ratio H SC /H SF in the preheating chamber ( 2 ) (where H SC denotes a filling height [m] of the iron scrap in the preheating chamber, and H SF denotes a preheating chamber interior height [m]) is 0.5 to 0.8, a carbonaceous material is used as an auxiliary heat source for melting the iron scrap in the melting chamber ( 1 ), and oxygen and the carbonaceous material are blown into the melting chamber ( 1 ) so that a carbon-oxygen ratio C/O (where C denotes a carbon amount [kg] in the carbonaceous material, and O denotes an oxygen blowing amount [Nm 3 ]) is not less than 0.70.

2 . The method for producing molten iron using an electric furnace according to claim 1 , wherein
an oxygen concentration in the preheating chamber ( 2 ) is less than 15 vol %.

3 . The method for producing molten iron using an electric furnace according to claim 1 , wherein
a blowing amount of the carbonaceous material into the melting chamber is 0.3 to 1.4 (kg/min) per ton of molten iron to be tapped, and the oxygen blowing amount is 20 to 40 (Nm 3 /hr) per ton of molten iron to be tapped.

4 . The method for producing molten iron using an electric furnace according to claim 1 , wherein
one or more auxiliary burners are installed in the melting chamber ( 1 ) and used to heat the iron scrap and molten iron in the melting chamber.

5 . The method for producing molten iron using an electric furnace according to claim 1 , wherein
in the electric furnace, the preheating chamber ( 2 ) is provided on and continuously with the melting chamber ( 1 ) at a position distant from an arc heating portion, and a scrap charge port ( 20 ) is provided at a top of the preheating chamber ( 2 ), and the iron scrap charged into the preheating chamber ( 2 ) through the scrap charge port ( 20 ) is filled in the preheating chamber ( 2 ) and in a space ( 1 a ) of the melting chamber ( 1 ) below the preheating chamber ( 2 ), and the iron scrap that is in the space ( 1 a ) is sequentially extruded toward the arc heating portion.

6 . The method for producing molten iron using an electric furnace according to claim 5 , wherein
the iron scrap in the space ( 1 a ) is sequentially extruded toward the arc heating portion by an extruder ( 3 ).

7 . The method for producing molten iron using an electric furnace according to claim 2 , wherein
a blowing amount of the carbonaceous material into the melting chamber ( 1 ) is 0.3 to 1.4 (kg/min) per ton of molten iron to be tapped, and the oxygen blowing amount is 20 to 40 (Nm 3 /hr) per ton of molten iron to be tapped.

8 . The method for producing molten iron using an electric furnace according to claim 2 , wherein
one or more auxiliary burners are installed in the melting chamber ( 1 ) and used to heat the iron scrap and molten iron in the melting chamber.

9 . The method for producing molten iron using an electric furnace according to claim 3 , wherein
one or more auxiliary burners are installed in the melting chamber ( 1 ) and used to heat the iron scrap and molten iron in the melting chamber.

10 . The method for producing molten iron using an electric furnace according to claim 7 , wherein
one or more auxiliary burners are installed in the melting chamber ( 1 ) and used to heat the iron scrap and molten iron in the melting chamber.

11 . The method for producing molten iron using an electric furnace according to claim 2 , wherein
in the electric furnace, the preheating chamber ( 2 ) is provided on and continuously with the melting chamber ( 1 ) at a position distant from an arc heating portion, and a scrap charge port ( 20 ) is provided at a top of the preheating chamber ( 2 ), and the iron scrap charged into the preheating chamber ( 2 ) through the scrap charge port ( 20 ) is filled in the preheating chamber ( 2 ) and in a space ( 1 a ) of the melting chamber ( 1 ) below the preheating chamber ( 2 ), and the iron scrap that is in the space ( 1 a ) is sequentially extruded toward the arc heating portion.

12 . The method for producing molten iron using an electric furnace according to claim 3 , wherein
in the electric furnace, the preheating chamber ( 2 ) is provided on and continuously with the melting chamber ( 1 ) at a position distant from an arc heating portion, and a scrap charge port ( 20 ) is provided at a top of the preheating chamber ( 2 ), and the iron scrap charged into the preheating chamber ( 2 ) through the scrap charge port ( 20 ) is filled in the preheating chamber ( 2 ) and in a space ( 1 a ) of the melting chamber ( 1 ) below the preheating chamber ( 2 ), and the iron scrap that is in the space ( 1 a ) is sequentially extruded toward the arc heating portion.

13 . The method for producing molten iron using an electric furnace according to claim 4 , wherein
in the electric furnace, the preheating chamber ( 2 ) is provided on and continuously with the melting chamber ( 1 ) at a position distant from an arc heating portion, and a scrap charge port ( 20 ) is provided at a top of the preheating chamber ( 2 ), and the iron scrap charged into the preheating chamber ( 2 ) through the scrap charge port ( 20 ) is filled in the preheating chamber ( 2 ) and in a space ( 1 a ) of the melting chamber ( 1 ) below the preheating chamber ( 2 ), and the iron scrap that is in the space ( 1 a ) is sequentially extruded toward the arc heating portion.

14 . The method for producing molten iron using an electric furnace according to claim 7 , wherein
in the electric furnace, the preheating chamber ( 2 ) is provided on and continuously with the melting chamber ( 1 ) at a position distant from an arc heating portion, and a scrap charge port ( 20 ) is provided at a top of the preheating chamber ( 2 ), and the iron scrap charged into the preheating chamber ( 2 ) through the scrap charge port ( 20 ) is filled in the preheating chamber ( 2 ) and in a space ( 1 a ) of the melting chamber ( 1 ) below the preheating chamber ( 2 ), and the iron scrap that is in the space ( 1 a ) is sequentially extruded toward the arc heating portion.

15 . The method for producing molten iron using an electric furnace according to claim 8 , wherein
in the electric furnace, the preheating chamber ( 2 ) is provided on and continuously with the melting chamber ( 1 ) at a position distant from an arc heating portion, and a scrap charge port ( 20 ) is provided at a top of the preheating chamber ( 2 ), and the iron scrap charged into the preheating chamber ( 2 ) through the scrap charge port ( 20 ) is filled in the preheating chamber ( 2 ) and in a space ( 1 a ) of the m

Assignees

• Jfe Steel Corp

Inventors

• Miwa Yoshihiro
• Tsutsumi Koichi
• Sumi Ikuhiro

Classifications

• F27D13/002

  Preheating scrap · CPC title

• C21C5/565

  Preheating of scrap · CPC title

• F27B3/18

  Arrangements of devices for charging · CPC title

• Y02P10/20

  Recycling · CPC title

• C21B11/10 Primary

  in electric furnaces · CPC title