Method and system of reducing non-ferrous metal content of scrap steel

Patent metadata

Field	Value
Publication number	US-11834728-B2
Application number	US-202217585131-A
Country	US
Kind code	B2
Filing date	Jan 26, 2022
Priority date	Jan 26, 2021
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

Methods of reducing copper metal content of shredded scrap steel are provided. The method includes continuously separating a first scrap steel fraction from an amount of scrap steel concurrently with separating a second fraction from the amount of scrap steel; continuously separating the second fraction and providing a nonmagnetic fraction and, concurrently, a third scrap steel fraction; grinding the nonmagnetic fraction followed by magnetic separation to provide a fourth scrap steel fraction and, concurrently, an enriched nonmagnetic fraction; continuously combining the first scrap steel fraction, the third scrap steel fraction, and the fourth scrap steel fraction to obtain a combined scrap steel product comprising scrap steel with reduced copper metal content; and introducing the combined scrap steel product to an electric arc furnace. Systems of reducing copper metal content of shredded scrap steel are also provided.

First claim

We claim:

1. A continuous method of reducing copper metal content of shredded scrap steel with non-ferrous material present therein, the method comprising:
continuously separating a first scrap steel fraction from an amount of scrap steel concurrently with separating a second fraction from the amount of scrap steel via a ballistic separator;
continuously magnetically separating the second fraction and providing a nonmagnetic fraction and, concurrently, a third scrap steel fraction;
grinding the nonmagnetic fraction followed by magnetic separation to provide a fourth scrap steel fraction and, concurrently, an enriched nonmagnetic metal fraction;
continuously combining the first scrap steel fraction, the third scrap steel fraction, and the fourth scrap steel fraction to obtain a combined scrap steel product comprising scrap steel with reduced copper metal content; and
introducing the combined scrap steel product to an electric arc furnace.

2. The method of claim 1 , wherein the copper metal content of the scrap steel is at least 0.30 weight percent copper.

3. The method of claim 1 , wherein the second fraction comprises iron and nonmagnetic material.

4. The method of claim 1 , wherein the nonmagnetic fraction is cryoground.

5. The method of claim 1 , wherein the enriched nonmagnetic metal fraction comprises one or more of stainless steel, copper, nickel, aluminum, manganese, chrome, gold, brass, and bronze.

6. The method of claim 1 , wherein the combined scrap steel product comprises less than or equal to 0.20 weight percent copper.

7. The method of claim 1 , further comprising separating a stainless steel enriched fraction from the enriched nonmagnetic metal fraction.

8. The method of claim 7 , wherein the combined scrap steel product and optionally the stainless steel enriched fraction comprises less than or equal to 0.20 weight percent copper.

9. The method of claim 7 , wherein the combined scrap steel product and optionally the stainless steel enriched fraction comprises between 0.16-0.19 weight percent copper.

10. The method of claim 7 , further comprising, prior to introducing the combined scrap steel product to the electric arc furnace, combining the stainless steel enriched fraction with the combined scrap steel product.

11. The method of claim 1 , further comprising, prior to introducing the combined scrap steel product to the electric arc furnace, combining the combined scrap steel product with at least one of pig iron or direct reduced iron (DRI).

12. The method of claim 1 , further comprising separating copper from the enriched nonmagnetic metal fraction to provide a separated, enriched copper product from the scrap steel.

13. A system for reducing copper metal content of shredded scrap steel, the system comprising:
a first separator configured to continuously receive an amount of scrap steel containing copper metal and to continuously provide a first scrap steel fraction with less than or equal to 0.20 weight percent copper and to provide a second fraction comprising iron and nonmagnetic material of greater than or equal to 0.50 weight percent copper;
a second separator configured to continuously receive the second fraction from the first separator and to provide a third scrap steel fraction and a nonmagnetic fraction; and
a third separator configured to continuously receive the nonmagnetic fraction and to provide a fourth scrap steel fraction and an enriched nonmagnetic metal fraction,
wherein the system is configured to continuously combine the first scrap steel fraction, the third scrap steel fraction, and the fourth scrap steel fraction and to obtain:
a combined scrap steel product having less than or equal to 0.20 weight percent copper, and
the enriched nonmagnetic metal fraction comprising copper and nonmagnetic metal.

14. The system of claim 13 , wherein the first separator comprises a shredded scrap steel ballistic separator.

15. The system of claim 13 , wherein the second separator comprises an electromagnetic separator.

16. The system of claim 13 , further comprising a grinder or cryogrinder configured to continuously receive the nonmagnetic fraction from the second separator.

17. The system of claim 13 , further comprising an electric arc furnace configured to receive the combined scrap steel product.

18. The system of claim 17 , wherein the system is further configured to combine the combined scrap steel product with at least one of pig iron or direct reduced iron (DRI) prior to introducing the combined scrap steel product to the electric arc furnace.

19. The system of claim 13 , wherein the system is further configured to provide a separated, enriched copper product from the scrap steel.

Assignees

• Nucor Corp

Inventors

• True Brad
• Hendrickson David W

Classifications

• C22B1/005 Primary

  Preliminary treatment of scrap (C22B1/02 - C22B1/26 take precedence) · CPC title

• C22B9/20

  Arc remelting · CPC title

• Y02P10/20

  Recycling · CPC title

• C22B7/005

  Separation by a physical processing technique only, e.g. by mechanical breaking · CPC title

• B03C1/247

  obtained by a rotating magnetic drum · CPC title