Method for producing molten pig iron

Patent metadata

Field	Value
Publication number	US-2025179594-A1
Application number	US-202318842513-A
Country	US
Kind code	A1
Filing date	Feb 28, 2023
Priority date	Mar 7, 2022
Publication date	Jun 5, 2025
Grant date	—

Abstract

A method for producing molten pig iron includes a first step of producing carbon-material-containing agglomerated ore from an iron-containing and carbon-containing raw materials, a second step of blowing an oxygen-containing gas into the carbon-material-containing agglomerated ore to reduce and melt it, thereby producing molten pig iron, and a third step of bringing a carbon-containing gas containing carbon monoxide and carbon dioxide produced as a by-product of the reduction into contact with a porous material, thereby recovering carbon, in which in the first step, the carbon recovered in the third step is used for a part of or an entirety of the carbon-containing raw material. The method may include, instead of the second step, a reduction step of heating the carbon-material-containing agglomerated ore to 1160 to 1450° C., and then cooling the carbon-material-containing agglomerated ore to obtain reduced iron, and a step of melting the reduced iron to produce molten pig iron.

First claim

1 . A method for producing molten pig iron, comprising:
a first step of producing a carbon-material-containing agglomerated ore from an iron-containing raw material and a carbon-containing raw material; a second step of blowing an oxygen-containing gas into the carbon-material-containing agglomerated ore to reduce and melt the carbon-material-containing agglomerated ore, thereby producing molten pig iron; and a third step of bringing a carbon-containing gas containing carbon monoxide and carbon dioxide produced as a by-product of the reduction into contact with a porous material, thereby recovering carbon, characterized in that: in the first step, the carbon recovered in the third step is used for a part of or an entirety of the carbon-containing raw material.

2 . The method for producing molten pig iron according to claim 1 , comprising, instead of the second step:
a reduction step of obtaining reduced iron in which the carbon-material-containing agglomerated ore is heated to 1160 to 1450° C., reduced, melted, and then cooled, and a melting step of producing molten pig iron in which the reduced iron is melted.

3 . The method for producing molten pig iron according to claim 1 , wherein in the third step, the carbon-containing gas further contains a gas containing carbon monoxide and carbon dioxide produced as a by-product of a refining step of molten iron.

4 . The method for producing molten pig iron according to claim 1 , further comprising, before bringing the carbon-containing gas into contact with the porous material in the third step, supplying hydrogen to the carbon-containing gas and heating the carbon-containing gas to 800 to 1200° C. to convert the carbon dioxide contained in the carbon-containing gas to carbon monoxide.

5 . The method for producing molten pig iron according to claim 4 , further comprising, after heating the carbon-containing gas but before bringing the carbon-containing gas into contact with the porous material in the third step, removing water contained in the carbon-containing gas.

6 . The method for producing molten pig iron according to claim 5 , comprising removing water contained in the carbon-containing gas and water generated through a reforming reaction of the carbon-containing gas so as to satisfy the following expression (1):

[

Math
.

1

]



[

H
2

⁢
O

]

/

(

[

H
2

⁢
O

]

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[

H
2

]

)

<
0.1

(
1
)

where [H 2 O] represents a water concentration (volume %) in a reformed mixed gas, and [H 2 ] represents a hydrogen concentration (volume %) in the reformed mixed gas.

7 . The method for producing molten pig iron according to claim 1 , wherein in the third step, the porous material is iron, and a part of the recovered carbon is iron carbide.

8 . The method for producing molten pig iron according to claim 1 , wherein a particle size of the carbon-containing raw material is 100 μm or less.

9 . The method for producing molten pig iron according to claim 1 , wherein in the first step, the carbon-containing raw material further contains biomass.

10 . The method for producing molten pig iron according to claim 1 ,
wherein: the iron-containing raw material is iron ores, and the method further comprises a pretreatment step of subjecting the iron ores to heat treatment in a temperature range of 300° C. to 1000° C. before the first step.

11 . The method for producing molten pig iron according to claim 2 , wherein in the third step, the carbon-containing gas further contains a gas containing carbon monoxide and carbon dioxide produced as a by-product of a refining step of molten iron.

12 . The method for producing molten pig iron according to claim 2 , further comprising, before bringing the carbon-containing gas into contact with the porous material in the third step, supplying hydrogen to the carbon-containing gas and heating the carbon-containing gas to 800 to 1200° C. to convert the carbon dioxide contained in the carbon-containing gas to carbon monoxide.

13 . The method for producing molten pig iron according to claim 3 , further comprising, before bringing the carbon-containing gas into contact with the porous material in the third step, supplying hydrogen to the carbon-containing gas and heating the carbon-containing gas to 800 to 1200° C. to convert the carbon dioxide contained in the carbon-containing gas to carbon monoxide.

14 . The method for producing molten pig iron according to claim 11 , further comprising, before bringing the carbon-containing gas into contact with the porous material in the third step, supplying hydrogen to the carbon-containing gas and heating the carbon-containing gas to 800 to 1200° C. to convert the carbon dioxide contained in the carbon-containing gas to carbon monoxide.

15 . The method for producing molten pig iron according to claim 12 , further comprising, after heating the carbon-containing gas but before bringing the carbon-containing gas into contact with the porous material in the third step, removing water contained in the carbon-containing gas.

16 . The method for producing molten pig iron according to claim 13 , further comprising, after heating the carbon-containing gas but before bringing the carbon-containing gas into contact with the porous material in the third step, removing water contained in the carbon-containing gas.

17 . The method for producing molten pig iron according to claim 14 , further comprising, after heating the carbon-containing gas but before bringing the carbon-containing gas into contact with the porous material in the third step, removing water contained in the carbon-containing gas.

18 . A metho

Assignees

• Jfe Steel Corp

Inventors

• Iwami Yuji
• Higuchi Takahide
• Murakami Taichi

Classifications

• C21B2100/00

  Handling of exhaust gases produced during the manufacture of iron or steel · CPC title

• C21B2100/26

  by adding additional fuel in recirculation pipes · CPC title

• C22B1/02

  Roasting processes (C22B1/16 takes precedence) · CPC title

• C22B1/24

  Binding; Briquetting {; Granulating} · CPC title

• C22B1/16

  Sintering; Agglomerating · CPC title