A method for producing molten pig iron into an electrical smelting unit

Patent metadata

Field	Value
Publication number	US-2026022430-A1
Application number	US-202218997165-A
Country	US
Kind code	A1
Filing date	Jul 29, 2022
Priority date	Jul 29, 2022
Publication date	Jan 22, 2026
Grant date	—

Abstract

A method of manufacturing molten pig iron into an electrical smelting unit. The method includes the following successive steps: providing a directly reduced iron product, feeding the DRI product into the smelting unit, feeding together with the DRI product at least one steel or ironmaking by-product-based material including at least 10% in weight of slag forming agents, and melting the DRI product and the at least one steel or ironmaking by-product-based material to produce molten pig iron. A steel manufacturing method using the pig iron is also provided.

First claim

1 - 11 . (canceled)

12 . A method for manufacturing molten pig iron in an electrical smelting unit, the method comprising the following steps of:
providing a directly reduced iron product; feeding the DRI product into the smelting unit; feeding, together with the DRI product, at a least one steel or ironmaking by-product-based material comprising at least 10% in weight of slag forming agents; and melting the DRI product and the at least one steel or ironmaking by-product-based material to produce molten pig iron.

13 . The method according to claim 12 wherein the steel or iron-making by-products forming the by-product-based material are chosen from at least one of the group consisting of: sinter dust, steelmaking sludges or dusts, smelting sludges or dusts, secondary metallurgy slag, electric arc furnace slag, basic oxygen furnace slag, mill scale and any of their combinations.

14 . The method according to claim 12 wherein the by-product-based material further includes an iron content upper than 20% in weight, at least a part of the iron being in an oxidized form.

15 . The method according to claim 12 wherein the slag forming agents are chosen from at least one of the group consisting of: CaO, lime, alumina, magnesia, aluminosilicate and any of their combinations.

16 . The method according to claim 12 wherein the steel or ironmaking by-product-based material is fed as briquettes or pellets.

17 . The method according to claim 16 wherein the briquettes or pellets are prepared according to the following methods:
crushing of steel or ironmaking by-products;
sieving of the crushed steel or ironmaking by-products;
mixing of the sieved steel or ironmaking by-products in appropriate amounts to reach a targeted composition of the steel or ironmaking by-product-based material; and
briquetting or pelletizing of the mixture.

18 . The method according to claim 12 wherein a carbon-containing material is also fed to the smelting unit.

19 . The method according to claim 18 wherein the carbon containing material is added in an amount sufficient to reach a final carbon content of 4.0 to 4.5% in weight in the pig iron.

20 . The method according to claim 12 wherein the DRI product is manufactured using a reducing gas containing at least 50% in volume of hydrogen before being loaded in said smelting furnace.

21 . A method for manufacturing steel employing the method as recited in claim 12 comprising the steps of:
transferring the pig iron from the smelting furnace to a converter; and
lowering a carbon content of the pig iron to a value below 2.1 percent in weight by blowing oxygen to obtain liquid steel.

22 . The method for manufacturing steel according to claim 21 wherein ferrous scraps are added to the pig iron in the converter, the ferrous scraps being melted.

Assignees

• Arcelormittal

Inventors

• Huber Jean-Christophe
• Sanchez Mathieu
• Deplechin Simon Pierre

Classifications

• C21C5/28

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

• C21B3/04 Primary

  Recovery of by-products, e.g. slag · CPC title

• C21B11/10 Primary

  in electric furnaces · CPC title

• C21B2200/00

  Recycling of non-gaseous waste material · CPC title

• C21B13/143

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