Production method of granular metallic iron

Patent metadata

Field	Value
Publication number	US-10407744-B2
Application number	US-201515310483-A
Country	US
Kind code	B2
Filing date	May 13, 2015
Priority date	May 15, 2014
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

This method is for producing granular metallic iron in which the relation between the mass ratio (mass %) of the volatile matter content contained in a carbonaceous reducing agent and the average gas flow rate (m/s) of the ambient gas in a heating furnace fulfills expression (1). Mass ratio of volatile matter content≤−4.62×average gas flow rate+46.7 . . . (1)

First claim

The invention claimed is:

1. A method for producing granular metallic iron, the method comprising:
agglomerating a mixture comprising an iron oxide-containing material and a carbonaceous reducing agent to obtain an agglomerate;
charging the agglomerate onto a hearth of a heating furnace and heating it, thereby reducing iron oxide in the agglomerate to obtain reduced iron; and
melting the reduced iron by further heating to cause the reduced iron to coalesce, thereby producing the granular metallic iron,
wherein, when the agglomerate is heated on the hearth of the heating furnace, an average gas flow rate of an atmospheric gas in the heating furnace is 0.340 in/sec or more, and a relationship between a mass ratio (%) by mass) of a volatile matter contained in the carbonaceous reducing agent and the average gas flow rate (m/sec) satisfies formula (1):
Mass ratio of volatile matter≤−4.62×average gas flow rate+46.7  (1).

2. The method according to claim 1 , wherein an oxygen amount/fixed carbon amount ratio is from 1.46 to 2.67, where the oxygen amount represents an amount of oxygen by mass percentage derived from the iron oxide-containing material and the fixed carbon amount represents an amount of fixed carbon by mass percentage derived from the carbonaceous reducing agent.

3. The method according to claim 1 , wherein the mixture further comprises a melting-point controlling agent.

4. The method according to claim 2 , wherein the mixture further comprises a melting-point controlling agent.

Assignees

• Kobe Steel Ltd

Inventors

• O Shorin
• Ito Shuzo

Classifications

• C22B1/245

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

• C22B1/24

  Binding; Briquetting {; Granulating} · CPC title

• C21B13/12 Primary

  in electric furnaces · CPC title

• C21B13/105

  Rotary hearth-type furnaces · CPC title

• C21B13/0066

  Preliminary conditioning of the solid carbonaceous reductant · CPC title