Method of continuous manufacturing of solidified steelmaking slag and associated device

Patent metadata

Field	Value
Publication number	US-11708302-B2
Application number	US-201716650595-A
Country	US
Kind code	B2
Filing date	Sep 28, 2017
Priority date	Sep 28, 2017
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

A method of continuous manufacturing of solidified steelmaking slag including the steps of solidifying molten steelmaking slag comprising at least 2% in weight of free lime so as to produce solidified slag particles having a diameter below 1 mm, the molten steelmaking slag being put in contact with at least a first carbonation gas during such solidification, cooling the solidified slag particles down to a temperature below or equal to 300° C., in a closed chamber, the solidified slag particles being put in contact with at least one second carbonation gas during such cooling. The invention is also related to an associated device.

First claim

What is claimed is:

1. A method of continuous manufacturing of solidified steelmaking slag comprising the steps of:
solidifying molten steelmaking slag including at least 2% in weight of free lime so as to produce solidified slag particles having a diameter below 1 mm, the molten steelmaking slag being put in contact with at least a first carbonation gas during such solidification, the first carbonation gas includes at least 20% in volume of CO 2 , between 5 and 30% in volume of CO, between 1 and 55% in volume of H 2 , between 1 and 55% in volume of N 2 and between 1 and 5% in volume of O 2 ; and
cooling the solidified slag particles down to a temperature below or equal to 300° C., in a closed chamber, the solidified slag particles being put in contact with at least one second carbonation gas during such cooling.

2. The method as recited in claim 1 wherein the first carbonation gas includes at least 50% in volume of CO 2 .

3. The method as recited in claim 1 wherein the first carbonation gas includes steam.

4. The method as recited in claim 3 wherein the first carbonation gas includes at least 20% in volume of steam.

5. The method as recited in claim 1 wherein the second carbonation gas includes at least 25% in volume of CO 2 .

6. The method as recited in claim 1 wherein the second carbonation gas is maintained at a temperature comprised between 300 and 500° C. during the cooling step.

7. The method as recited in claim 1 wherein the second carbonation gas includes steam.

8. The method as recited in claim 7 wherein the second carbonation gas includes at least 25% in volume of steam.

9. The method as recited in claim 1 wherein the cooling rate of solidified slag particles is between 1 and 100° C./min during the cooling step.

10. The method as recited in claim 1 wherein the solidified slag particles are kept in motion during the cooling step.

11. The method as recited in claim 10 wherein the solidified slag particles are kept in motion during the cooling step by injection of a third gas into the closed chamber.

12. The method as recited in claim 11 wherein the third gas includes at least 20% in volume of CO 2 .

13. The method as recited in claim 1 further comprising exhausting at least a part of the gases inside the closed chamber and collecting the exhausted gases to be recycled as the first carbonation gas, the second carbonation gas or a third gas for keeping the solidified slag particles in motion.

14. The method as recited in claim 1 wherein the first carbonation gas, the second carbonation gas or at least a third gas for keeping the solidified slag particles in motion includes exhausts gases from ironmaking, steelmaking, sintering or coking plant.

15. The method as recited in claim 1 wherein the second carbonation gas includes at least 25% in volume of CO 2 , between 5 and 30% in volume of CO, between 1 and 55% in volume of H 2 , between 1 and 55% in volume of N 2 , and between 1 and 5% in volume of O 2 .

16. The method as recited in claim 1 wherein a stay time within the closed chamber is below 30 minutes.

17. The method as recited in claim 1 wherein at least 60% of free lime of the molten steelmaking slag is transformed into calcium carbonates.

18. The method as recited in claim 1 , wherein said solidifying and cooling is performed in comprising:
a closed chamber, the closed chamber including:
a solidification device able to produce solidified slag particles having a diameter inferior or equal to 1 mm;
a bottom porous wall; and
gas injectors for injecting the at least first carbonation gas and the at least one second carbonation gas.

19. The method as recited in claim 18 further comprising an exhaust gas collector and a gas recirculator.

20. The method as recited in claim 18 wherein the solidification device is an atomizer.

21. The method as recited in claim 18 wherein the solidification device is a granulator.

22. The method as recited in claim 18 wherein at least one of the injectors is connected to an ironmaking, steelmaking, sintering or coking plant.

23. A method of continuous manufacturing of solidified steelmaking slag comprising the steps of:
solidifying molten steelmaking slag including at least 2% in weight of free lime so as to produce solidified slag particles having a diameter below 1 mm, the molten steelmaking slag being put in contact with at least a first carbonation gas during such solidification; and
cooling the solidified slag particles down to a temperature below or equal to 300° C., in a closed chamber, the solidified slag particles being put in contact with at least one second carbonation gas during such cooling, wherein the second carbonation gas includes at least 25% in volume of CO 2 , between 5 and 30% in volume of CO, between 1 and 55% in volume of H 2 , between 1 and 55% in volume of N 2 , and between 1 and 5% in volume of O 2 .

Assignees

• Arcelormittal

Inventors

• De Coninck Eric
• Infante Ivonne
• Mattos Dos Santos Rafael
• Ounoughene Ghania
• Van Gerven Thomas

Classifications

• C04B5/00 Primary

  Treatment of  {metallurgical}  slag  (manufacture of slag wool C03B; in, or for, the production of metals C21B, C22B); Artificial stone from molten  {metallurgical}  slag  {(other cast stone C04B32/005; mechanical aspects B28B1/54)} · CPC title

• C21B3/08 Primary

  Cooling slag · CPC title

• C22B7/04 Primary

  Working-up slag · CPC title

• C21B2400/024

  with the direct use of steam or liquid coolants, e.g. water · CPC title

• C21B2400/026

  using air, inert gases or removable conductive bodies · CPC title