Steel decarburization using carbon dioxide

Patent metadata

Field	Value
Publication number	US-11970748-B2
Application number	US-202017428936-A
Country	US
Kind code	B2
Filing date	Feb 12, 2020
Priority date	Feb 13, 2019
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

A process to decarburize steel can include contacting molten iron-containing material with a carbon dioxide in an electric arc furnace, a ladle furnace, or a vacuum degassing unit, or a combination thereof to decarburize at least a portion of the molten iron-containing material. The molten iron-containing material is preferably molten iron oxide.

First claim

The invention claimed is:

1. A process to decarburize steel, the process comprising:
contacting a molten iron-containing material with a carbon dioxide (CO 2 ) containing gas to decarburize at least a portion of the molten iron-containing material; and
producing a steel material from the decarburized iron-containing material;
wherein the steel material has a carbon content of less than 0.5 wt. % based on the total weight of the steel; and
wherein the molten iron-containing material is molten iron oxide.

2. The process of claim 1 , further comprising the step of introducing carbon particles to the molten iron-containing material via a carbon inlet.

3. The process of claim 1 , wherein the CO 2 containing gas is provided during a primary steel processing step of melting direct reduced iron, pig iron, iron ore, scrap iron, or any combination thereof.

4. The process of claim 1 , further comprising agitating the molten iron containing material with the CO 2 containing gas.

5. The process of claim 1 , further comprising contacting the molten iron-containing material with an oxygen (O 2 ) containing gas.

6. The process of claim 5 , further comprising providing the CO 2 containing gas in a direction opposite of the flow the oxygen (O 2 ) containing gas.

7. The process of claim 1 , wherein the contact of the molten iron-containing material and CO 2 containing gas is a secondary steel processing step.

8. The process of claim 7 , wherein the molten iron-containing material comprises molten slag on a top portion of a molten iron oxide material and the method further comprises providing the CO 2 containing gas to a bottom portion of the molten iron oxide material.

9. The process of claim 1 , wherein the molten iron-containing material is molten iron oxide and the process further comprises contacting the molten iron oxide material and CO 2 containing gas under a reduced pressure.

10. The process of claim 9 , wherein the reduced pressure is a third steel processing step.

11. The process of claim 9 , further comprising agitating the molten iron oxide with the CO 2 containing gas.

12. The process of claim 1 , wherein the CO 2 containing gas includes nitrogen (N 2 ), argon (Ar), or both.

13. A process to decarbonize iron-containing material, the process comprising:
(a) contacting an iron-containing material with a carbon dioxide (CO 2 ) containing gas to at least partially decarbonize the iron-containing material;
(b) providing the at least partially decarbonized iron-containing material to a secondary steel process and contacting the iron-containing material with a CO 2 containing gas to produce a decarbonized iron containing material having a carbon content lower than the decarbonized iron-containing material of step (a); and
(c) contacting the decarbonized iron containing material of step (b) with a CO 2 containing gas under a reduced pressure to produce a decarbonized steel material having a carbon content lower than the decarbonized iron containing material of step (b);
wherein the decarbonized iron-containing material of step (b) and/or step (c) is a steel material having a carbon content of less than 0.5 wt %.

14. The process of claim 13 , wherein step (a) is performed in an electric arc furnace, step (b) is performed in a ladle furnace, and step (c) is performed in a ladle vacuum degassing unit.

15. The process of claim 14 , further comprising providing the CO 2 containing gas to a bottom portion of the EAF, a bottom portion of the ladle furnace, a bottom portion of the ladle vacuum degassing unit, or any combination thereof.

16. The process of claim 13 , wherein the decarbonized iron-containing material of step (b) and/or step (c) is a steel material having a carbon content of less than 0.05 wt.

17. The process of claim 13 , further comprising contacting the iron-containing material of step (a) with an oxygen containing gas.

18. The process of claim 17 , further comprising simultaneous or substantially simultaneous contacting the iron-containing material with the CO 2 containing gas and the O 2 containing gas.

19. A process to decarburize steel, the process comprising:
producing a decarburized iron-containing material by decarburizing at least a portion of molten iron-containing material which comprises carbon by contacting the molten iron-containing material with a carbon dioxide (CO 2 ) containing gas; and
producing a steel material from the decarburized iron-containing material;
wherein the steel material has a carbon content of less than 0.5 wt. % based on the total weight of the steel; and
wherein a vacuum gassing treatment is not necessary to yield the steel material.

Assignees

• Sabic Global Technologies Bv

Inventors

• Al-Harbi Mansour

Classifications

• C21D3/04 Primary

  Decarburising · CPC title

• C21C7/068 Primary

  Decarburising · CPC title

• C21C7/10

  Handling in a vacuum · CPC title

• C21C7/072

  Treatment with gases (C21C7/06, C21C7/064, C21C7/068 take precedence) · CPC title

• C21C5/52

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