Method for recycling iron-containing by-products discharged from coal-based molten ironmaking process, system therefor, and reduced iron agglomeration system

Patent metadata

Field	Value
Publication number	US-2016024611-A1
Application number	US-201414773848-A
Country	US
Kind code	A1
Filing date	Mar 26, 2014
Priority date	Mar 26, 2013
Publication date	Jan 28, 2016
Grant date	—

Abstract

There is provided a method and system for recycling by-products containing large amounts of useful components and discharged in the form of dust and sludge from a coal-based molten iron making process to reuse the by-products in a reduced iron agglomeration process. The system includes: a fluidized reduction furnace reducing fine iron ore; a reduced iron tank connected to the fluidized reduction furnace through a reduced iron discharge pipe for storing the reduced iron and supplying the reduced iron in an agglomeration system; an agglomeration system agglomerating the reduced iron transferred from the reduced iron tank; and a transfer unit transferring compactions of by-products discharged from a molten iron making process through a by-product supply pipe. The compactions of the by-products are supplied to at least one selected from the group consisting of the fluidized reduction furnace, the reduced iron supply pipe, and the reduced iron tank.

First claim

1 . A method for recycling iron-containing by-products discharged from a molten iron making process in the form of dust and sludge containing moisture, the method comprising:
agglomerating the by-products discharged from the molten iron making process to form by-product compactions; and forming reduced iron compactions by mixing reduced iron with the by-product compactions and agglomerating the reduced iron mixed with the by-product compactions.

2 . The method of claim 1 , wherein the agglomerating of the by-products comprises:
drying a portion or all of the sludge; preparing a by-product mixture having a predetermined moisture content by mixing the dried sludge with the dust or with the dust and remaining sludge; agglomerating the by-product mixture to form agglomerated by-products; and drying the agglomerated by-products to form by-product compactions.

3 . The method of claim 2 , wherein the drying of the portion or all of the sludge comprises adding the dust to the portion or all of the sludge.

4 . The method of claim 2 , wherein the by-product mixture has a moisture content of 30 wt % or less.

5 . (canceled)

6 . (canceled)

7 . The method of claim 1 , wherein the by-product compactions have a moisture content of 5 wt % or less.

8 . (canceled)

9 . (canceled)

10 . The method of claim 2 , wherein after the drying of the agglomerated by-products, the method further comprises sorting the by-product compactions to separate by-product compactions having a particle size of 1 mm to 10 mm.

11 . (canceled)

12 . The method of claim 1 , wherein in the forming of the reduced iron compactions, the by-product compactions and the reduced iron are mixed at a weight ratio greater than 0:10 but equal to or less than 9:1.

13 . The method of claim 1 , wherein the reduced iron is obtained by reducing iron ore in a reduction furnace under a reducing atmosphere.

14 . The method of claim 1 , wherein the forming of the reduced iron compactions comprises:
reducing iron ore in a fluidized reduction furnace under a reducing atmosphere so as to form reduced iron; discharging the reduced iron through a reduction furnace discharge pipe; storing the reduced iron in a reduced iron tank; supplying the reduced iron from the reduced iron tank to a forceful transfer tank through a reduced iron supply pipe; and supplying the reduced iron to an agglomeration device to agglomerate the reduced iron, wherein the by-product compactions are supplied to one or more of the above-listed operations and mixed with the reduced iron.

15 . (canceled)

16 . The method of claim 14 , further comprising mixing the reduced iron with the by-product compactions by supplying the by-product compactions to one or more of the fluidized reduction furnace, the reduction furnace discharge pipe, and the reduced iron tank.

17 . The method of claim 14 , further comprising mixing the reduced iron with the by-product compactions by supplying the by-product compactions to one or both of the reduced iron supply pipe and the forceful transfer tank.

18 . (canceled)

19 . A system for agglomerating iron-containing by-products discharged from a molten iron making process in the form of dust and sludge containing moisture, the system comprising:
a sludge dryer receiving the sludge through a pipe and drying the sludge; a by-product agglomeration device receiving the dust and the sludge dried by the sludge dryer respectively through pipes and mixing and agglomerating the dust and sludge to form agglomerated by-products; and a compaction dryer receiving the agglomerated by-products from the by-product agglomeration system and removing moisture from the agglomerated by-products to form by-product compactions.

20 . The system of claim 19 , wherein the sludge dryer comprises an additional pipe to receive the dust and mixes and dries the sludge and the dust.

21 . The system of claim 19 , wherein the by-product agglomeration device is an agitating device, a briquetting device, a pelletizer, or an extruder.

22 . The system of claim 19 , wherein the by-product agglomeration device comprises an additional pipe through which the sludge containing moisture is supplied.

23 . (canceled)

24 . The system of claim 19 , further comprising a classifier sorting the by-product compactions according to particle sizes of the by-product compactions and returning fine or coarse by-product compactions to the by-product agglomeration system through a pipe.

25 . A system for agglomerating reduced iron obtained by reducing fine iron ore in a molten iron making process, the system comprising:
a fluidized reduction furnace reducing iron ore to produce reduced iron; a reduced iron tank connected to the fluidized reduction furnace through a reduction furnace discharge pipe and storing the reduced iron discharged from the fluidized reduction furnace; a forceful transfer tank connected to the reduced iron tank through a reduced iron supply pipe and supplying the reduced iron from the reduced iron tank to an agglomeration system; a reduced iron agglomeration device agglomerating the reduced iron supplied from the forceful transfer tank; and a by-product supply pipe through which by-product compactions produced by agglomerating by-products discharged from a molten iron making process are transferred to the reduced iron agglomeration system.

26 . The system of claim 25 , wherein the by-product supply pipe is connected to at least one selected from the group consisting of the fluidized reduction furnace, the reduction furnace discharge pipe, and the reduced iron tank.

27 . The system of claim 25 , wherein the by-product supply pipe is connected to at least one selected from the group consisting of the reduced iron supply pipe and the forceful transfer tank.

28 . The system of claim 25 , further comprising a transfer unit transferring the by-product compactions by using a flow of carrier gas, gravity, or a mechanical device.

29 . (canceled)

30 . (canceled)

31 . (canceled)

32 . (canceled)

Assignees

• Posco

Inventors

• Cho Min-Young
• Kim Hyun-Soo
• Lee Dal-Hoi
• Lee Jong-Yeol
• Yoon Shi-Kyung
• Choi Moo-Eob
• Ko Chang-Kuk

Classifications

• C22B1/242

  with binders · CPC title

• C21B13/004

  in a continuous way by reduction from ores · CPC title

• C21B13/0033

  In fluidised bed furnaces or apparatus containing a dispersion of the material · CPC title

• C22B1/16 Primary

  Sintering; Agglomerating · CPC title

• C22B7/02

  Working-up flue dust · CPC title