Process for manufacturing reduced iron agglomerates

Patent metadata

Field	Value
Publication number	US-10144981-B2
Application number	US-201314377373-A
Country	US
Kind code	B2
Filing date	Feb 28, 2013
Priority date	Feb 28, 2012
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

A process for manufacturing reduced iron agglomerates which comprises introducing starting agglomerates that comprise both an iron oxide-containing material and a carbonaceous reducing agent onto the hearth of a moving-bed heating furnace, and heating the agglomerates to reduce the iron oxide contained in the agglomerates, wherein the iron oxide-containing material contained in the starting agglomerates has a mean particle diameter of 4 to 23 μm and contains at least 18% of particles having diameters of 10 μm or less. By the use of such starting agglomerates, the process attains: an improvement in the yield of reduced iron agglomerates having large particle diameters; a reduction in the manufacturing time, said reduction leading to an enhancement in the productivity; and a remarkable reduction in the content of impurities such as sulfur in the reduced-iron agglomerates.

First claim

The invention claimed is:

1. A method for manufacturing reduced iron agglomerates, the method comprising:
charging a compact comprising an iron oxide-containing material, a carbonaceous reducing agent, and a melting-point-adjusting agent onto a hearth of a moving-bed heating furnace,

heating the compact to reduce iron oxide in the compact; further heating the compact to at least partially melt the compact; and coalescing an iron component, thereby producing the reduced iron agglomerates, wherein
the iron oxide-containing material in the compact consists of iron ore,
the iron oxide-containing material has a mean particle diameter of 4 to 23 pm; and a proportion of particles with a particle diameter of 10 pm or less in the iron oxide-containing material is 18% by mass or more.

2. The method according to claim 1 , wherein the iron oxide-containing material located in a central portion of the compact has a mean particle diameter of from 4 to 23 μm.

3. The method according to claim 1 , wherein the compact is in the form of a pellet or briquette.

4. The method according to claim 1 , wherein the compact further comprises a binder, a MgO supply material, a sulfur component, dolomite, and/or a CaO supply material.

5. The method according to claim 1 , wherein the heating temperature is from 1200 to 1500° C.

6. The method according to claim 1 , wherein the heating was done in a nitrogen atmosphere.

7. The method according to claim 1 , wherein the melting-point-adjusting agent is limestone, fluorite, dolomite or a mixture there.

8. The method according to claim 1 , further comprising:
prior to said charging, pulverizing the iron oxide-containing material.

Assignees

• Kobe Steel Ltd

Inventors

• Kikuchi Shoichi
• Harada Takao
• Yoshida Shingo

Classifications

• C21B13/105

  Rotary hearth-type furnaces · CPC title

• C21B3/00

  General features in the manufacture of pig-iron (mixers for pig-iron C21C1/06) · CPC title

• C21B13/0046

  making metallised agglomerates or iron oxide · CPC title

• B22F9/22

  using gaseous reductors · CPC title

• C22B1/245 Primary

  with carbonaceous material for the production of coked agglomerates · CPC title