Method for ironmaking by smelting reduction in stir-generated vortex

Patent metadata

Field	Value
Publication number	US-11091816-B2
Application number	US-201716318020-A
Country	US
Kind code	B2
Filing date	Apr 28, 2017
Priority date	Sep 27, 2016
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

A method for ironmaking by smelting reduction in a stir-generated vortex includes: (1) placing a pig iron in an induction furnace, and then heating the pig iron to a molten state to form a molten iron, and maintaining the molten iron to be greater than or equal to 1450° C.; (2) stirring a center of the molten iron to form a vortex with a height-to-diameter ratio of 0.5-2.5, and continuously performing stirring; (3) mixing and grinding on an iron-containing mineral, a reducing agent and a slag-forming agent in a mass ratio of 1:(0.1-0.15):(0.25-0.4) to obtain a powder mixture, spraying and blowing the powder mixture to a center of the vortex, performing a reduction reaction, and stopping the stirring after the molten iron and molten slags are obtained, wherein a waste gas is produced; and (4) discharging the molten iron and the molten slags respectively, and exhausting a treated waste gas.

First claim

What is claimed is:

1. A method for ironmaking by smelting reduction in a stir-generated vortex, comprising:
(1) placing a pig iron in an induction furnace, heating the pig iron to a molten state to form a molten iron, and maintaining a temperature of the molten iron to be greater than or equal to 1,450° C., wherein an amount of the pig iron is 5-20 vol % of an induction furnace body;
(2) stirring the molten iron to form a vortex with a height-to-diameter ratio of 0.5-2.5, and continuously performing stirring;
(3) spraying and blowing a mixture of an iron-containing mineral, a reducing agent and a slag-forming agent to a center of the vortex to cause a reduction reaction, and stopping stirring after molten iron and molten slags are obtained and a waste gas is produced, wherein a mass ratio of the iron-containing mineral, the reducing agent, and the slag-forming agent is 1:(0.1-0.15):(0.25-0.4); and
(4) discharging the molten iron and the molten slags respectively, and exhausting a treated waste gas.

2. The method according to claim 1 , wherein in the step (1), the induction furnace comprises a slag discharge opening and a molten iron discharge opening; the molten iron discharge opening is formed in a lower part on one side of the induction furnace, and the slag discharge opening is formed in an upper part on the other side of the induction furnace;
the induction furnace is provided with a stirring paddle, a stirring paddle lifting system, a powder spraying device, an air hood, a flue gas purifying system, a waste heat recovery system, and a washing tower, wherein the stirring paddle is arranged in the induction furnace, the stirring paddle lifting system is connected with the stirring paddle, the powder spraying device is arranged at a top on one side of the induction furnace, the air hood is arranged above the induction furnace, an inlet of the flue gas purifying system is connected with the air hood through a pipeline, an inlet of the waste heat recovery system is connected with an outlet of the flue gas purifying system through a pipeline, an inlet of the washing tower is connected with an outlet of the waste heat recovery system through a pipeline, an outlet of the washing tower communicates with atmosphere, and the stirring paddle lifting system is used for replacing the stirring paddle.

3. The method according to claim 2 , wherein the stirring paddle is a graphite stirring paddle.

4. The method according to claim 2 , wherein in the step (2), the stirring paddle is inserted to ⅓-½ of a liquid level of the molten iron for a center stirring with a center stirring speed of 50-200 r/min.

5. The method according to claim 1 , wherein in the step (3), the iron-containing mineral, the reducing agent and the slag-forming agent are mixed, ground, and then sprayed and blown to the center of the vortex through a powder spraying device.

6. The method according to claim 1 , wherein in the step (3), the iron-containing mineral is iron ore, the reducing agent is pulverized coal, and the slag-forming agent is calcium oxide.

7. The method according to claim 1 , wherein in the step (3), a reduction rate of the iron-containing mineral is greater than or equal to 95.5%, and an iron content in the molten slags is less than or equal to 0.35% by mass.

8. The method according to claim 2 , wherein in the step (4), the molten slags are placed in an upper layer and the molten iron is placed in a lower layer in the induction furnace, wherein the molten slags are discharged from the slag discharge opening and the molten iron is discharged from the molten iron discharge opening.

9. The method according to claim 2 , wherein the step (4), the waste gas is conveyed to the flue gas purifying system via the air hood for purification, a waste heat is then recovered through the waste heat recovery system.

Assignees

• Univ Northeastern

Inventors

• Zhang Ting An
• Liu Yan
• Dou Zhi He
• Zhang Zi Mu
• Lv Guo Zhi

Classifications

• C21C1/04 Primary

  Removing impurities other than carbon, phosphorus or sulfur · CPC title

• C21B2300/02

  Particular sequence of the process steps · CPC title

• C21B11/10 Primary

  in electric furnaces · CPC title

• Y02P10/25

  Process efficiency · CPC title

• H05B6/367

  for melting furnaces · CPC title