APPARATUS FOR MANUFACTURING COMPACTED IRONS AND APPARATUS FOR MANUFACTURING MOLTEN IRON COMPRISING

THE SAME

Technical Field

The present invention relates to an apparatus for manufacturing compacted iron and an apparatus for manufacturing molten iron using the same, and more specifically to an apparatus for manufacturing compacted iron that is charged into a melter-gasifier and is smoothly melted therein and an apparatus for manufacturing molten iron including the same. Background Art

The iron and steel industry is a core industry that supplies the basic materials needed in construction and in the manufacture of automobiles, ships, home appliances, and many other products we use. It is also an industry with one of the longest histories that has progressed together with humanity. In an iron foundry, which plays a pivotal roll in the iron and steel industry, after molten iron, which is pig iron in a molten state, is produced by using iron ore and coal as raw materials, steel is produced from the molten iron and then supplied to customers. Currently, approximately 60% of the world''s iron production is produced using a blast furnace method that has been in development since the 14th century. According to the blast furnace method, iron ore, which has gone through a sintering process, and coke, which is produced using bituminous coal as a raw material, are charged into a blast furnace together and oxygen is supplied thereto to reduce the iron ore to iron, thereby manufacturing molten iron.

The blast furnace method, which is the most popular in plants for manufacturing molten iron, requires that raw materials have strength of at least a predetermined level and have grain sizes that can ensure permeability in the furnace, taking into account reaction characteristics. For that reason, as described above, coke that is obtained by processing specific raw coal is used as a carbon source to be used as a fuel and as a reducing agent. Also,

sintered ore that has gone through a successive agglomerating process is mainly used as an iron source.

Accordingly, the modern blast furnace method requires raw material preliminary processing equipment, such as coke manufacturing equipment and sintering equipment. That is, it is necessary to be equipped with subsidiary facilities in addition to the blast furnace, and to also have equipment for preventing and minimizing pollution generated from the subsidiary facilities. Therefore, there is a problem in that a heavy investment in the additional facilities and equipment leads to increased manufacturing costs.

In order to solve these problems with the blast furnace method, significant effort has been made in iron works all over the world to develop a smelting reduction process that produces molten iron by directly using raw coal as a fuel and a reducing agent and by directly using fine ore, which accounts for more than 80% of the world''s ore production.

An installation for manufacturing molten iron directly using raw coal and fine iron ore is disclosed in US Patent No. 5,534,046. The apparatus for manufacturing molten iron disclosed in US Patent No. 5,534,046 includes three-stage fluidized-bed reactors forming a bubbling fluidized bed therein, and a melter-gasifier connected thereto. The fine iron ore and additives at room temperature are charged into the first fluidized-bed reactor and successively go through three-stage fluidized-bed reactors. Since hot reducing gas produced from the melter-gasifier is supplied to the three-stage fluidized-bed reactors, the temperature of the iron ore and additives, which were at room temperature, is raised by contact with the hot reducing gas. Simultaneously, 90% or more of the iron ore and additives are reduced and 30% or more of them are sintered, and they are charged into the melter- gasifier.

A coal packed bed is formed in the melter-gasifier by supplying coal thereto. Therefore, iron ore and additives at room temperature are melted and slagged in the coal packed bed and are then discharged as molten iron and slag. The oxygen supplied from a plurality of tuyeres installed on the

outer wall of the melter-gasifier burns a coal packed bed and is converted to a hot reducing gas. Then, the hot reducing gas is supplied to the fluidized- bed reactors, thereby reducing iron ore and additives, and is exhausted outside. However, since a high speed gas flow is formed in the upper portion of the melter-gasifier included in the above-mentioned apparatus for manufacturing molten iron, there is a problem in that the fine reduced iron and sintered additives charged into the melter-gasifier are scattered and loosened. Furthermore, when fine reduced iron and sintered additives are charged into the melter-gasifier, there is a problem in that permeability of gas and liquid in the coal packed bed of the melter-gasifier cannot be ensured.

In order to solve the above problems, the method for briquetting fine reduced iron and plasticized additives and charging them into the melter- gasifier has been developed. In the above process for manufacturing molten iron, fine reduced iron and plasticized additives are molded into briquettes and then the briquettes are crushed to a suitable size. The crushed briquettes are charged into the melter-gasifier.

In this case, since the crusher, which is used for crushing the briquettes, crushes briquettes in a hot environmental condition, thermal deformation and crack occur to the crusher. Therefore, since a period of exchanging installations is short, there is problem in that it is difficult to use it in a long term.

DISCLOSURE Technical Problem The present invention is contrived to improve durability of a crusher and extend a period of exchanging installations, thereby reducing a consuming time for operating of exchanging installations and improving workability. Technical Solution An apparatus for manufacturing compacted iron according to an embodiment of the present invention includes at least one pair of molding rolls that compress fine materials and manufacture compacted iron, and a

crusher that crushes the compacted iron manufactured in the molding rolls. The crusher includes a shaft that is provided with a cooling passage, and a roll that is provided with protrusions on an outer radial surface thereof and surrounds the shaft to be combined therewith. The roll may include a shoulder that surrounds the shaft, and the protrusions may be arranged to be spaced apart from each other along a longitudinal direction of the shaft on the shoulder.

The shoulder may include grooves that are formed between the protrusions such that the grooves absorb a thermal deformation of the protrusions. The grooves may substantially have a cross-sectional shape of a rectangle.

The protrusions may be arranged in an area having a width that is less than a width along a longitudinal direction of the shaft of the shoulder.

The cooling passage may be arranged in an area having a width that is greater than a width of an area where the protrusions are arranged.

The cooling passage may be formed in a center axis of the shaft and surround the shaft with a spiral shape.

The roll may be made of one body. The protrusions may substantially have a cross-sectional shape of a rectangle. A wear resistant coating film may be formed on a surface of the protrusions.

The fine materials may include fine direct reduced iron and plasticized additives.

The apparatus for manufacturing compacted iron may further include a second crusher that crushes the crushed compacted iron in the crusher again such that a grain size distribution of the compacted iron is controlled.

Meanwhile, an apparatus for manufacturing molten iron according to the present invention includes an apparatus for manufacturing compacted iron that compacts fine materials, and a melter-gasifier into which the compacted iron manufactured in the apparatus for manufacturing compacted iron is charged. The melter-gasifier melts the compacted iron. The apparatus for manufacturing compacted iron includes at least one pair of

molding rolls that compress fine direct reduced iron and manufacture compacted iron, and a crusher that crushes the compacted iron manufactured in the molding rolls. The crusher includes a shaft that is provided with a cooling passage, and a roll that is provided with a plurality of protrusions on an outer radial surface thereof and surrounds the shaft. Advantageous Effects

Hot wear resistance and hot tensile strength of the crusher are largely improved and a period of exchanging the crushers is extended, and thereby process cost can be saved and efficiency of the process can be improved. DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of an apparatus for manufacturing compacted iron according to an embodiment of the present invention.

FIG. 2 is a perspective view of a crusher according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the crusher according to an embodiment of the present invention.

FIG. 4 is a schematic view of the apparatus for manufacturing molten iron according to an embodiment of the present invention.

BEST MODE Exemplary embodiments of the present invention will be explained in detail below with reference to the attached drawings. The embodiments of trie present invention are merely to illustrate the present invention and the present invention is not limited thereto.

FIG. 1 schematically shows an apparatus for manufacturing compacted iron 100 according to an embodiment of the present invention.

FIG. 1 schematically shows an apparatus for compacting and crushing fine direct reduced iron (DRI) and manufacturing compacted iron. A structure of the apparatus for manufacturing compacted iron 100 shown in FIG. 1 is merely to illustrate the present invention and the present invention is not limited thereto. Therefore, the apparatus for manufacturing compacted iron

100 can be formed as other structures.

Particularly, although only fine direct reduced iron as fine materials

is shown to be charged into a charging device 11 in FIG. 1, this is merely to illustrate the present invention and the present invention is not limited thereto. Therefore, the fine materials may further contain plasticized additives that plasticize the fine direct reduced iron. As shown in FIG. 1, the apparatus for manufacturing compacted iron

100 includes a charging device 11, a pair of molding rolls 20, a crusher 30, and a second crusher 40. In addition, the apparatus for manufacturing compacted iron 100 includes a level control device 13, an open/close type valve 15, a charging hopper 25, and a guide chute 29 if necessary. The charging device 11 variably controls an amount of the fine direct reduced iron charged from an upper side thereof to be 60 tons or less per hour while discharging it into a lower side thereof and supplying it to the pair of molding rolls 20. As described above, since a large amount of fine direct reduced iron can be treated, the compacted iron can be continuously manufactured.

The fine materials can be manufactured by passing mixtures of iron ore and additives through a fluidized-bed reduction reactor. The fine materials manufactured as in the above method can be supplied to the charging device 11. The charging device 11 can restore the fine materials having a temperature of 7000C or more and a volume specific gravity of about 2ton/m3. Since a discharging pressure of a final fluidized-bed reduction reactor is about 3 bar and a flux thereof is about 3000m3/ h, hot fine materials are transferred by pressure to the charging device 11. The compacted iron can be manufactured by only using hot fine direct reduced iron without plasticized additives. However, the plasticized additives are used in order for the fine direct reduced iron to stick to an inner side of the fluidized-bed reduction reactor. The fine materials may include plasticized additives of a range from about 3wt% to about 20wt% .

The level control device 13 is installed below the charging device 11. The level control device 13 detects a level of the fine materials stored in the charging device 11 and interrupts transportation of the fine materials from the fluidized-bed reduction reactor or controls a transportation amount

thereof if the level reaches a predetermined value. In addition, the open/ close type valve 15 is installed below the charging device 11. The open/ close type valve 15 includes an open/close type plate 15a for opening and closing a lower end of the charging device 11 and an oil pressure actuator 15b for controlling the open/close type plate 15a. An amount of the fine materials entering from the charging device 11 to the charging hopper 25 is controlled by using the open/close type valve 15.

The charging hopper 25 is located above a gap formed between the pair of molding rolls 20, thereby charging the fine materials into the gap formed between the pair of molding rolls 20. As described above, since the fine materials are continuously charged by using the charging hopper 25, a large amount of compacted iron can be continuously manufactured by using the pair of molding rolls 20.

The pair of molding rolls 20 include two molding rolls 20a and 20b. The pair of molding rolls 20 are connected to the charging device 11 located thereabove, thereby compressing the fine materials charged from the charging device 11. Since two molding rolls 20a and 20b rotate toward a lower direction to be opposite to each other, continuous connected compacted iron can be manufactured by compressing the fine materials. More specifically, among the pair of molding rolls 20, the first molding roll 20a is installed to be fixed while the second molding roll 20b is installed to be movable in order to prevent the pair of molding rolls 20 from malfunctioning by charging a large amount of the fine materials thereto. An axis of the second molding roll 20b is supported by an oil pressure cylinder 27 etc., and thereby the second molding roll 20b is installed to be capable of moving in a horizontal direction toward the first molding roll 20a. Therefore, even if a large amount of the fine materials are charged, the compacted iron can be continuously manufactured since the second molding roll 20b can variably and elastically move in a horizontal direction toward the first molding roll 20a.

The molding rolls 20 operate by offsetting protrusions formed on a surface of the first molding roll 20a offset with those formed on a surface of

the second molding roll 20b, and thereby corrugated compacted iron is manufactured. Therefore, the compacted iron can be easily crushed in a following process. When the compacted iron is manufactured using the above-described method, the volume in a width direction of the molding roll is increased, thereby increasing productivity. The corrugated compacted iron manufactured as described above is guided by a guide chute 29, and then is coarsely crushed in the crusher 30. The guide chute 29 continuously guides the compacted iron manufactured in the pair of molding rolls 20 to the crusher 30. The compacted iron is coarsely crushed in the crusher 30. The crusher 30 can crush corrugated compacted iron to an average grain size of 50mm or less. Here, if the corrugated compacted iron is crushed to have an average grain size of over 50mm, a severe load is applied to the second crusher 40, and thereby the second crusher 40 can be out of order. Therefore, the corrugated compacted iron is crushed to have an average grain size of 50mm or less. As described above, the corrugated compacted iron is crushed to be manufactured to have an indeterminate form, and thereby it is suitable to be used in the melter-gasifier.

The coarsely crushed compacted iron as described above enters into the second crusher 40 and is then crushed again in the second crusher 40. The second crusher 40 is connected to the crusher 30, and thereby the corrugated compacted iron that is coarsely crushed in the crusher 30 is crushed again in the second crusher 40 such that a grain size distribution of the compacted iron is controlled after the corrugated compacted iron is coarsely crushed in the crusher 30.

The second crusher 40 crushes the coarsely crushed compacted iron again, and thereby a grain size distribution of the compacted iron is controlled. The second crusher 40 includes a pair of crushing rolls 40a and 40b installed to be spaced apart from each other. The pair of crushing rolls 40a and 40b can be one body or can be separated as disk types.

When compacted iron with a grain size that is suitably distributed is charged into a melter-gasifier, melting ability and permeability can be

suitably maintained during melting and slagging of the compacted iron after it is supplied to the melter-gasifier. In addition, an oxygen tuyere attached to a lower portion of the melter-gasifier can be prevented from being damaged by being melted. Therefore, an improvement of efficiency and productivity of a process for manufacturing molten iron can be contrived.

A structure of the crusher 30 provided in the apparatus for manufacturing compacted iron 100 of FIG. 1 will be explained in detail below with reference to FIGs. 2 and 3. The structure of the crusher 30 is merely to illustrate the present invention and the present invention is not limited thereto.

FIG. 2 is a schematic perspective view of the crusher 30 included in the apparatus for manufacturing compacted iron 100 of FIG. 1. As shown in FIG. 2, the crusher 30 includes a shaft 32 provided with a cooling passage 32a and a roll 34 surrounding the shaft 32 to be combined therewith. Protrusions 34b are formed on an outer radial surface of the roll 34. Since the roll 34 is made of one body, it is simple to fix and maintain the roll 34 and is little damaged during the crushing process.

The roll 34 includes a shoulder 34a surrounding the shaft 32, and the protrusions 34b are arranged to be spaced apart from each other along a longitudinal direction of the shaft 32 on the shoulder 34a. The protrusions 34b form a column while being arranged to be on a surface of the roll 34 with a constant interval therebetween. The protrusions 34b substantially have a cross-sectional shape of a rectangle. Since a wear resistant coating film is formed on a surface of the protrusions 34b, abrasion of the protrusions 34 b can be prevented.

FIG. 3 shows a schematic cross-section of the roll 34 for explaining a passage formed in the shaft 32. As shown in FIG. 3, the protrusions 34b are arranged in an area with a width that is less than a width along a longitudinal direction of the shaft 32 of the shoulder 34a. More specifically, the protrusions 34b are arranged on an about a center portion of the shoulder 34a. The protrusions 34b are not arranged at edges of the shoulder 34a.

In addition, a cooling passage 32a formed on an outer surface of the

shaft 32 is arranged in an area with a width that is greater than that of an area where the protrusions 34b are arranged. That is, the cooling passage

32a is arranged to have a width that is greater than that of an area where the protrusions 34 are formed. Therefore, protrusions 34b at both ends of the shoulder 34a where thermal stress is particularly high during operation can be more effectively cooled.

The cooling passage 32a is formed in an axis of the shaft 32 and has a spiral shape to surround an outer surface of the shaft 32. Therefore, after the cooling water enters into the axis of the shaft 32 and flows between the shaft 32 and the shoulder 34a in a spiral manner, thereby cooling the protrusions 34b, it is discharged in an opposite direction of the axis of the shaft from which it enters.

Meanwhile, a groove 34c is formed between the protrusions 34b of tiie shoulder 34a, and thereby the protrusions 34b are thermally expanded by high temperature to absorb deformed portions during operation. The groove 34c can be formed to substantially have a cross-sectional shape of a rectangle.

FIG. 4 schematically shows an apparatus for manufacturing molten iron 1000 including the apparatus for manufacturing compacted iron 100 of FIG. 1. FIG. 4 schematically shows a process for manufacturing molten iron using the compacted iron manufactured in the apparatus for manufacturing compacted iron.

As shown in FIG. 4, the compacted iron with a grain size distribution that is suitably controlled is supplied to the melter-gasifier 70 through a hot transferring device 50. The apparatus for manufacturing molten iron 100 further includes the hot transferring device 50 and the melter-gasifier 70 in addition to the above-described apparatus for manufacturing compacted iron

100. The hot transferring device 50 is thermally insulated from the outside in order to raise thermal efficiency of the crushed compacted iron and maintain the compacted iron at a high temperature. Since a structure of the hot transferring device 50 can be easily understood by those skilled in the art, a detailed description thereof is omitted.

Lumped coal or coal briquettes are supplied to the melter-gasifier 70.

For example, the lumped coal can be coal with a grain size of over 8mm.

The coal is collected from a production site. For example, the coal briquettes can be molded to be compressed by a press from coal with a grain size of 8mm or less. The coal is collected from a production site.

After the lumped coal or coal briquettes are charged into the melter- gasifier 70 and oxygen O2 is supplied to melt the compacted iron, the molten iron is discharged through a tap. Using the above-described method, molten iron with a good quality can be easily manufactured. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

WHAT IS CALIMED IS

1. An apparatus for manufacturing compacted iron, the apparatus comprising: at least one pair of molding rolls that compress fine materials and manufacture compacted iron; and a crusher that crushes the compacted iron manufactured in the molding rolls, and wherein the crusher comprises a shaft that is provided with a cooling passage, and a roll that is provided with protrusions on an outer radial surface thereof and surrounds the shaft to be combined therewith.

2. The apparatus of Claim 1, wherein the roll comprises a shoulder that surrounds the shaft, and wherein the protrusions are arranged to be spaced apart from each other along a longitudinal direction of the shaft on the shoulder.

3. The apparatus of Claim 2, wherein the shoulder comprises grooves that are formed between the protrusions such that the grooves absorb a thermal deformation of the protrusions.

4. The apparatus of Claim 3, wherein the grooves substantially have a cross-sectional shape of a rectangle.

5. The apparatus of Claim 2, wherein the protrusions are arranged in an area having a width that is less than a width along a longitudinal direction of the shaft of the shoulder.

6. The apparatus of Claim 5, wherein the cooling passage is arranged in an area having a width that is greater than a width of an area where the protrusions are arranged.

7. The apparatus of Claim 6, wherein the cooling passage is formed in a center axis of the shaft and surrounds the shaft with a spiral shape.

8. The apparatus of Claim 1, wherein the roll is made of one body.

9. The apparatus of Claim 1, wherein the protrusions substantially have a cross-sectional shape of a rectangle.

10. The apparatus of Claim 1, wherein a wear resistant coating film is formed on a surface of the protrusions.

11. The apparatus of Claim 1, wherein the fine materials comprise fine direct reduced iron and plastidzed additives.

12. The apparatus of Claim 1 further comprising a second crusher that crushes the crushed compacted iron in the crusher again such that a grain size distribution of the compacted iron is controlled.

13. An apparatus for manufacturing molten iron, the apparatus comprising: an apparatus for manufacturing compacted iron that compacts fine materials; and a melter-gasifier into which the compacted iron manufactured in the apparatus for manufacturing compacted iron is charged, the melter-gasifier melting the compacted iron, wherein the apparatus for manufacturing compacted iron comprises at least one pair of molding rolls that compress fine direct reduced iron and manufacture compacted iron, and a crusher that crushes the compacted iron manufactured in the molding rolls, and

wherein the crusher comprises a shaft that is provided with a cooling passage, and a roll that is provided with a plurality of protrusions on an outer radial surface thereof and surrounds the shaft.

14. The apparatus of Claim 13, wherein the roll comprises a shoulder that surrounds the shaft, and wherein the protrusions are arranged to be spaced apart from each other along a direction of the shaft on the shoulder.

15. The apparatus of Claim 14, wherein the shoulder comprises grooves that are formed between the protrusions such that the grooves absorb a thermal deformation of the protrusions.

16. The apparatus of Claim 15, wherein the grooves are formed on both sides of the roll.

17. The apparatus of Claim 14, wherein the protrusions are arranged on the shoulder in an area having a width that is less than a width of the shoulder.

18. The apparatus of Claim 17, wherein the cooling passage is arranged in an area having a width that is greater than a width of an area where the protrusions are arranged.

19. The apparatus of Claim 18, wherein the cooling passage is formed in a center axis of the shaft and surrounds the shaft with a spiral shape.

20. The apparatus of Claim 13, wherein the roll is made of one body.

21. The apparatus of Claim 13, wherein the protrusions substantially have a cross-sectional shape of a rectangle.

22. The apparatus of Claim 13, wherein a wear resistant coating film is formed on a surface of the protrusions.

23. The apparatus of Claim 13, wherein the fine materials comprise fine direct reduced iron and plasticized additives.

24. The apparatus of Claim 13 further comprising a second crusher that crushes the crushed compacted iron in the crusher again such that a grain size distribution of the compacted iron is controlled.

25 An apparatus for manufacturing compacted iron and molten iron, substantially herein described with reference to the foregoing examples and drawings.