Direct reduced iron (dri) heat treatment, products formed therefrom, and use thereof

Patent metadata

Field	Value
Publication number	US-2019085420-A1
Application number	US-201816138022-A
Country	US
Kind code	A1
Filing date	Sep 21, 2018
Priority date	Sep 21, 2017
Publication date	Mar 21, 2019
Grant date	—

Abstract

Heat treatment of DRI is performed in order to form a DRI product with a metallic shell around at least a portion of the DRI. The heat treatment may be delivered through the use of a plasma torch, a gas burner, an oven, or any other like heat source. The heat treatment may heat the DRI for a fraction of a second and quickly cool the DRI in order to melt the surface and form the metallic shell without vaporizing a significant portion of the DRI and without losing a significant amount of the latent energy in the DRI. During storage and transport of the DRI product, the DRI product is less likely to fracture, the DRI product has less exposed surface area of DRI, and results in reduced DRI fines and/or DRI dust cause by the DRI product rubbing together when compared to traditional types of DRI.

First claim

What is claimed is:

1 . A method of forming a direct reduced iron (DRI) product, comprising:
heating DRI at a temperature for a time to melt at least a portion of an outer surface of the DRI; and wherein the heating results in the DRI product having a DRI core and a metallic outer shell formed around at least the portion of the outer surface of the DRI core.

2 . The method of claim 1 , further comprising direct reducing iron ore using a reducing gas or carbon source to form the DRI.

3 . The method of claim 1 , wherein the heating comprises passing the DRI through a heat source, wherein a temperature of the heating ranges between 440 degrees Fahrenheit to 20,000 degrees Fahrenheit.

4 . The method of claim 3 , wherein passing the DRI through the heat source comprises dropping the DRI and using gravity, or providing a motive force.

5 . The method of claim 1 , wherein the heating is performed through a plasma torch.

6 . The method of claim 1 , wherein the heating is performed by passing the DRI through a gas burner, an oven, or any other conductive or radiant heat source.

7 . The method of claim 1 , wherein the time exposed to the temperature ranges from 0.05 to 5 seconds.

8 . The method of claim 1 , wherein the DRI is one or more DRI pellets.

9 . The method of claim 1 , wherein the DRI product has a diameter ranging from 3 mm to 20 mm.

10 . The method of claim 1 , further comprising:
pre-heating the DRI before performing the heating at the temperature for the time to melt at least the portion of the outer surface of the DRI.

11 . A direct reduced iron (DRI) product, comprising:
a DRI core formed from DRI; and a metallic outer shell formed around at least a portion of the DRI core.

12 . The DRI product of claim 11 , wherein the metallic outer shell is formed by heating the DRI at a temperature for a time to melt at least a portion of the outer surface of the DRI; and wherein the heating results in the DRI product having the DRI core and the metallic outer shell formed around at least a portion of the DRI core.

13 . The DRI product of claim 11 , wherein the DRI is formed by direct reducing iron ore using a reducing gas or carbon source.

14 . The DRI product of claim 12 , wherein the heating comprises passing the DRI through a heat source, wherein a temperature of the heating ranges between 440 degrees Fahrenheit to 20,000 degrees Fahrenheit.

15 . The DRI product of claim 14 , wherein the passing the DRI through the heat source comprises dropping the DRI and using gravity, or providing a motive force.

16 . The DRI product of claim 12 , wherein the heating is performed through a plasma torch.

17 . The DRI product of claim 12 , wherein the heating is performed by passing the DRI through a gas burner, an oven, or any other conductive or radiant heat source.

18 . The DRI product of claim 12 , wherein the time exposed to the temperature ranges from 0.05 to 5 seconds.

19 . The DRI product of claim 12 , wherein the DRI is one or more DRI pellets.

20 . The DRI product of claim 11 , wherein the DRI product has a diameter ranging from 3 mm to 20 mm.

Assignees

• Nucor Corp

Inventors

• True Bradford Granger
• Hendrickson David William

Classifications

• C21B13/0046 Primary

  making metallised agglomerates or iron oxide · CPC title

• C21B13/0093

  Protecting against oxidation · CPC title

• C21B13/143

  Injection of partially reduced ore into a molten bath · CPC title

• C21B13/12

  in electric furnaces · CPC title

• C21B13/0086 Primary

  Conditioning, transformation of reduced iron ores · CPC title