1
Specification STAVE, BLAST FURNACE, AND BLAST FURNACE OPERATION METHOD
Field of the Invention
[0001]
The present invention relates to a stave, a blast furnace having the stave, and a blast furnace operation method.
Priority is claimed on Japanese Patent Application No. 2009-263589, filed November 19, 2009, the content of which is incorporated herein by reference.
Related Art
[0002]
Existing blast furnaces frequently use a structure in which a stave is provided inside an iron shell, and firebrick is provided inside the stave. The inner surface of the blast furnace is exposed to a charged material descending inside the furnace while exposed to extreme heat inside the furnace, and undergoes mechanical wear. And after the firebrick is worn and disappears within a certain period, the surface of the stave is damaged and worn. In order to address damage and wear, a structure in which concave portions are arranged on the surface of the stave inside the fiimace, and a refractory material is fitted into the concave portions is being developed (see Patent Document 1).
Reference Documents Patent Documents
[0003]
[Patent Document 1] Japanese Unexamined Patent Application, First

2 Publication No. 2001-49316
Summary of the Invention
Problems to be Solved by the Invention
[0004]
In the inner surface of the blast furnace, a bosh section and a belly section come into contact with a root portion of a high-temperature cohesive zone (a region where an ore in a charged material starts to be softened and molten, and ores in a semi-molten state are fused and connected into a plate shape), and undergoes damage or mechanical wear, particularly, due to high temperature. In regard to the high-temperat\ire cohesive zone, it can be said that the fitted refractory material has insufficient durability.
[0005]
An object of the invention is to provide a stave which is provided in each of a bosh section and a belly section that ensures high durability even in a root portion of a high-temperature cohesive zone, a blast furnace having the stave, and a blast fiimace operation method.
Methods for Solving the Problem
[0006]
The invention is made from the viewpoint of knowledge obtained from careful study by the inventors, that is, knowledge that an accretion layer has a protective fiinction against heat loads and wear in the root portion of the cohesive zone (self-lining effect).
Usually, in a period of single refractory life of about 15 years from blowing-in to blowing-out of the blast furnace, after a firebrick provided inside the blast furnace disappears due to damage or mechanical wear caused by heat shock in the comparatively

3 early years, about two or three years from blowing-in, an accretion layer resulting from a
charged material is produced in the vicinity of the surface of the stave inside the furnace.
In the invention, as a configuration for promoting the production of an accretion layer
(accretion) which covers the surface of the stave, from the viewpoint of knowledge
described above, the protrusions which protrude toward the inside of the furnace in the
surface of the stave inside the blast furnace are used. As the material for the stave body,
copper or copper-alloy having high heat conductivity and high heat flux capability is
used.
The invention has used the following means so as to solve the above-described problem and to attain an object. A specific configuration is as follows.
[0007]
(1) An aspect of the invention provides a stave which is provided in an irmer circumference of each of a bosh section and a belly section of a blast fiimace. The stave includes a copper or a copper-alloy stave body which has a reference surface facing an internal space of the blast furnace, and a plurality of protrusions which protrude from the reference surface toward an inside of the blast fiimace.
In this stave, the reference surface of the stave body is formed as the irmer surface of the blast fiimace, and when the cohesive zone of the charged material descends inside the blast fumace, the descending rate of the root portion of the cohesive zone (the region where an ore in the charged material starts to be softened and molten, and ores in a semi-molten state are fused and connected into a plate shape) of the charged material is reduced by protrusions which protrude from the reference surface toward the inside of the fumace. Accordingly, an accretion is cooled. In this way, it is possible to allow the accretion to grow along the reference surface of the stave body and to coat the reference surface with the accretion. As a result, the accretion serves as a protective

4 layer, and the reference surface is not directly exposed to the high-temperature cohesive
zone, thereby increasing heat resistance as a stave for a bosh section and a belly section.
In particular, in this stave, a copper or copper-alloy stave body having high heat conductivity and high heat flux capability is used. Accordingly, even if the coating of the reference surface peels off due to changes in the operating conditions of the blast furnace, or the like, the charged material which subsequently descends and includes ores in a semi-molten state is reduced in rate. The charged material is rapidly cooled and attached to the reference surface, thereby reproducing the coating layer of the accretion early. With the self-lining effect using the accretion, ample durability is obtained as a stave for a bosh section and a belly section.
[0008]
(2) It is preferable that the stave described in (1) further includes a cooling
channel of a stave body which is provided inside the stave body and through which a
fluid cooling the stave body flows, and cooling channels of protrusions which are
provided inside the protrusions and through which a fluid cooling the protrusions flows.
In this stave, since the material for the stave body is copper or copper-alloy having high heat conductivity and high heat flux capability, the protrusions are sufficiently cooled by the stave body cooling channel inside the stave body. Meanwhile, if the protrusion cooling channels are formed inside the protrusions to directly cool the protrusions, the temperature of the surface decreases, thereby further promoting the production of the accretion.
[0009]
(3) It is preferable that the stave described in (1) further includes a plurality of
stave body temperature detection units which are arranged along the reference surface
inside the stave body, and a protrusion temperature detection unit which is arranged

5 inside each protrusion.
In this stave, the thickness of the accretion layer on the reference surface of the stave body and the residual thickness of the stave body are estimated on the basis of the detection temperatures detected by the temperature detection units. Accordingly, it is possible to determine integrity of the stave body and the furnace profile. The cooling state of the stave or other parameters is adjusted on the basis of the determination result, appropriate growth of the accretion is achieved, and the thickness of the accretion layer on the reference surface of the stave body is appropriately adjusted. As a result, it is possible to protect the stave body against heat loads and wear and to prevent deterioration of the furnace profile due to excessive growth of the accretion. With the maintenance of an appropriate profile, it becomes possible to stabilize a blast furnace operation.
[0010]
(4) In the stave described in (1), it is preferable that a distance between adjacent protrusions is in the range of 500 to 1000 mm.
If the distance between adjacent protrusions is greater than 1000 mm, the accretion which is produced starting with the protrusion and attached may not be produced and attached in the vicinity of the lower end of the protrusion at the high position. For this reason, it is difficult to form the accretion layer at a predetermined thickness evenly over the entire reference surface between adjacent protrusions. Accordingly, it is difficult to obtain a sufficient self-lining effect for protection against heat loads and mechanical wear in the root portion of the cohesive zone. That is, it becomes difficult to protect the stave body.
If the distance between adjacent protrusions is smaller than 500 mm, the charged material which descends between adjacent protrusions and includes ores in a semi-molten

6 state is reduced in rate, and the accretion layer which is produced on the reference
surface during cooUng excessively increases in thickness. If the accretion layer is
produced to an excessive thickness, the accretion layer interferes with stable descent of
the charged material. When the accretion layer peels off due to changes in the operating
conditions of the blast furnace, or the like, this causes significant changes in the furnace
profile of the bosh section and the belly section. Accordingly, it is undesirable for
maintaining stable operation of the blast furnace.
[0011]
(5) In the stave described in (4), it is preferable that, in the bosh section, the protrusions are provided such that a relation between a protrusion amount El from the reference surface and a distance Dl between each protrusion and another adjacent protrusion satisfies Expression (A), in the belly section, the protrusions are provided such that a relation between a protrusion amount E2 from the reference surface and a distance D2 between each protrusion and another adjacent protrusion satisfies Expression (B). D1=E1 xtan[90°-(al-ei)] ...(A) D2 = E2 X tan(e2)=E2 x tan[90° - (a2 - 02)] ... (B)
[0012]
In Expressions, 91 is 75° which is the inclination angle of an accretion attached to the reference surface in the bosh section, 92 is 85° to 88° which is the inclination angle of an accretion attached to the reference surface in the belly section, al is 77° to 82° which is the inclination angle of the stave used in the bosh section, and a2 is 90° which is the inclination angle of the stave used in the belly section.
At present, a general charged material includes an ore-based charged material having a particle size of 8 to 25 mm and a coke-based charged material having a particle

7 size of 20 to 55 mm which are alternately charged into the blast furnace in a layered
marmer. In the case of the stave which is provided in the bosh section in the vicinity of
the root portion of the cohesive zone of the charged material including ores in a
semi-molten state, the inclination angle 61 is substantially constant at 75°. al is the
inclination angle of the bosh section of the blast furnace, and in a usual blast furnace, al
is designed in a range of 77° to 82°. In the case of the stave which is provided in the
belly section, the inclination angle 92 is empirically estimated to be about 85° to 88°.
The inclination angle a2 of the belly section is 90° and is designed to be constant.
[0013]
In this stave, the protrusion amounts El and E2 and the distances Dl and D2 of the protrusions of the stave provided in the bosh section and the stave provided in the belly section satisfy the relations defined by Expression (A) and Expression (B). Accordingly, the charged material which descends inside the furnace and includes ores in a semi-molten state is reduced in rate, cooled, and attached to the reference surface R. Therefore, it is possible to efficiently coat the entire reference surface R with the growing accretion layer and to sufficiently protect the stave body against heat loads and wear.
Since the protrusion amounts El and E2 and the distances Dl and D2 of the protrusions of the stave provided in the bosh section and the stave provided in the belly section satisfy the relations defined by Expression (A) and Expression (B), it is possible to prevent the accretion layer from growing at an excessive thickness on the reference surface R. When the accretion layer peels off due to changes in the operating conditions of the blast furnace, or the like, it is possible to prevent significant changes in the furnace profile of the bosh section and the belly section, and to avoid trouble relating to the operation, such as deterioration of the descent of the charged material during a

8 blast furnace operation, making it possible to maintain stable operation of the blast
furnace for a long period of time.
[0014]
When the distances Dl and D2 between adjacent protrusions of the respective staves are set in a range of 500 to 1000 mm which is a desirable distance between the protrusions, the protrusion amounts El and E2 of the protrusions of the stave provided in the bosh section and the stave provided in the belly section are set from Dl and D2 and Expressions (A) and (B).
Since the protrusions of the stave of each of the bosh section and the belly section protrude from the reference surface toward the inside of the furnace, the protrusions are likely to be worn due to heat from the high-temperatvire charged material or abrasion. For this reason, from the viewpoint of the balance between the wear rate of the protrusions by the high-temperature charged material and the growth rate of the accretion on the reference surface by the protrusions, in order to sufficiently exhibit a durability improvement effect with self-lining of the stave body, it is preferable that the protrusion amounts El and E2 of the protrusions in both the staves of the bosh section and the belly section from the reference surface R are in a range of 50 to 150 mm.
[0015]
(6) In the stave described in (1), it is preferable that the protrusions are provided continuously or intermittently in a circumferential direction inside the blast furnace.
In this stave, with the protrusions provided continuously on the entire circumference along the circumferential direction inside the blast furnace, it is easy to appropriately maintain the circumference balance of the blast furnace, thereby satisfactorily maintaining the operation of the blast furnace.
The protrusions in the stave may be arranged intermittently (discontinuously) in

9 the circumferential direction of the blast furnace 1. In this case, although various
geometric patterns, such as a lattice pattern and a zigzag pattern, may be used, a
point-symmetrical structure taking into consideration the circumference balance is
preferably used.
[0016]
(7) In the stave described in (1), it is preferable that a plurality of grooves are
formed in the reference surface.
In this stave, a plurality of grooves are formed in the reference surface, making it possible to prevent heat inside the blast furnace from escaping outside the blast furnace.
(8) In the stave described in (7), it is preferable that a refractory material is
provided in concave portions that are formed by the reference surface and the protrusions,
and the grooves.
In this stave, the refractory material is provided in the concave portions and the grooves, making it possible to prevent damage to the stave body and the protrusions. It also becomes easy to form the furnace profile of the blast furnace.
[0017]
(9) Another aspect of the invention provides a blast furnace which includes the
stave described in any one of (1) to (8).
It is preferable that the stave which is provided in each of the bosh section and the belly section of the blast furnace according to another aspect of the invention is provided in a region of the belly section or the bosh section exposed to the root portion of the cohesive zone from the lower part of the shaft section of the blast fiimace.
In this blast fiamace, the stave is provided in a region of the bosh section or the belly section exposed to high temperature by the root portion of the cohesive zone.

10 Accordingly, in a period of single refractory life of usually 15 years from blowing-in to
blowing-out of the blast furnace, even after the firebrick provided inside the furnace
disappears due to damage or mechanical wear caused by heat shock in the comparatively
early years, about two or three years from blowing-in, it is possible to allow the charged
material to be attached to the reference surface of the stave body to form the accretion
layer. Therefore, it is possible to obtain the effect (self-lining effect) that the accretion
layer can perform protection against heat loads and wear in the root portion of the
cohesive zone.
[0018]
In the bosh section and the belly section of the blast furnace of the related art, in an operation period of about 15 years from blowing-in to blowing-out of the blast furnace, the firebrick and the stave are likely to be damaged and worn due to extreme heat in the root portion of the cohesive zone. For this reason, when there is a rapid change in the furnace profile, stable operation of the blast furnace becomes difficult.
In contrast, in the blast fiimace according to another aspect of the invention, the stave has a copper or copper-alloy stave body having high heat conductivity and high heat flux capability, and the protrusions which protrude from the reference surface toward the inside of the furnace. In particular, the stave is provided in a region of each of the bosh section and the belly section exposed to high temperature by the root portion of the cohesive zone inside the blast furnace. Therefore, it is possible to form the accretion layer on the reference surface early after the firebrick inside the furnace disappears in the comparatively early years, about two or three years from blowing-in of the blast furnace, and to stably maintain the accretion layer. As a result, it is possible to stably operate the blast furnace with little change in the fiimace profile, and to extend the life of the blast furnace.

11
[0019]
(10) In the blast furnace described in (9), it is preferable that a plurality of stave
body temperature detection units arranged along the reference surface and the protrusion
temperature detection unit arranged inside each protrusion are provided inside the stave
body of either the stave used in the bosh section or the stave used in the belly section, and
the blast furnace further includes an accretion estimation unit which estimates a thickness
of an accretion from the reference surface of the stave body and a residual thickness of
the stave body based on temperatures detected by the stave body temperature detection
units and the protrusion temperature detection unit.
In this blast furnace, the stave body temperature detection units and the protrusion temperature detection unit detect the temperature of the belly section or the bosh section from the lower part of the shaft section of the blast fiimace. The accretion estimation unit estimates the thickness of the accretion layer on the reference surface of the stave body and the residual thickness of the stave body on the basis of the detected temperatures. Therefore, it is possible to determine integrity of the furnace profile. The cooling state of the stave or other parameters is adjusted on the basis of the determination result, making it possible to prevent deterioration of the furnace profile due to excessive growth of the accretion. With the maintenance of an appropriate profile, it becomes possible to stabilize a blast furnace operation.
[0020]
(11) Still another aspect of the invention provides a blast furnace operation
method which operates the blast furnace described in (10). The blast furnace operation
method includes a temperature detection process which detects temperatures of the stave
body and the protrusions by the stave body temperature detection units and the protrusion
temperature detection unit, an accretion determination process which determins whether

12 or not the thickness of the accretion and the residual thickness of the stave body
estimated by the accretion estimation unit are smaller than a predetermined value, and a
temperature control process which controUs a combustion temperature inside the blast
furnace or the temperatures of the stave body and the protrusions based on a
determination in the accretion determination step.
In this blast furnace operation method, first, in the temperature detection step, the temperatures of the stave body and the protrusions are detected. Next, in the accretion determination step, it is determined whether or not the thickness of the accretion and the residual thickness of the stave body estimated by the accretion estimation unit are smaller than a predetermined value. If the thickness of the accretion is equal to the predetermined value, the temperatures of the stave body and the protrusions are continuously detected.
When the thickness of the accretion is smaller than the predetermined value, in the temperature control step, cooling of the stave is enhanced, or the operating conditions or the charged material distribution are adjusted to decrease the temperature in the blast furnace. When the thickness of the accretion is greater than the predetermined value, in the temperature control step, in order to reduce the accretion, cooling of the stave is modified, or the operating conditions or the charged material distribution are adjusted to increase the temperature in the blast furnace.
That is, it is possible to perform operational adjustment such that the coating necessary for protecting the stave 10 provided in each of the bosh section and the belly section is formed in the stave.
Brief Description of the Drawings [0021]

13 FIG. 1 is a schematic view showing a blast furnace according to a first
embodiment of the invention.
FIG. 2 is a sectional view showing a stave provided in each of the bosh section and the belly section of the blast furnace.
FIG. 3 is a front view showing the stave of the blast furnace.
FIG. 4 A is a perspective sectional view showing the stave of the blast furnace.
FIG. 4B is a perspective sectional view showing a modification of the stave of the blast furnace.
FIG. 5 is a rear view showing the stave of the blast furnace.
FIG. 6 is a schematic view showing a temperature measurement system of the blast furnace.
FIG. 7 is a graph showing temperature measiarement of the blast furnace.
FIG. 8 is a schematic view showing a state where an accretion to the blast fiamace is deficient.
FIG. 9 is a schematic view showing a state where an accretion to the blast furnace is appropriate.
FIG. 10 is a schematic view showing a state where an accretion to the blast furnace is excessive.
FIG. 11 is a flowchart showing a process for a blast furnace operation method.
FIG. 12 is a sectional view showing a stave provided in each of a bosh section and a belly section according to a second embodiment of the invention.
FIG. 13 is a front view showing a stave in the bosh section and the belly section.
FIG. 14 is a rear view showing a stave in the bosh section and the belly section.
Detailed Description of the Invention

14 [0022]
Hereinafter, embodiments of the invention will be described with reference to the drawings. [First Embodiment]
Referring to FIG. 1, the blast furnace 1 has a cylindrical ftimace body 2 which is constructed on the foundation ground.
The furnace body 2 has a cylindrical shape, and is divided into a throat section SI, a shaft section S2, a belly section S3, a bosh section S4, a tuyere section S5, and a blast furnace bottom section 86 sequentially from an upper gas collection mantel 3. In general, the inner diameter of the shaft section S2 expands downward, the inner diameter of the belly section S3 is the maximum diameter, and the iimer diameter of the bosh section S4 is reduced downward.
[0023]
The furnace body 2 is usually provided with a charging apparatus in the gas collection mantel 3, and a granular charged material 4 is charged from the charging apparatus into the blast furnace 1. As the charged material 4, an ore-based charged material having a particle size of about 8 to 25 mm and a coke-based charged material having a particle size of about 20 to 55 mm are alternately charged. As a result, in the throat section SI and the shaft section S2 of the ftimace, a lumpy zone 4 A in which iron ore and coke are alternately laminated is formed.
In the furnace body 2, tuyeres 5 are provided at the upper part of the blast furnace bottom section S6, and hot blast 5A is supplied from the tuyeres 5. With the hot blast 5A, coke in the lumpy zone 4A is burned and further increases in temperature, and raceways 5B (spaces having a high void ratio where high-rate gas is supplied from the tuyeres 5 and coke before the tuyeres 5 is fluidized) are formed by high-temperature gas

15 in the vicinity of the tuyeres 5. With extreme heat of the raceways 5B, iron ore in the
lumpy zone 4A is molten.
[0024]
Coke burning and iron ore melting are sequentially carried out at the lower part of the lumpy zone 4 A, and a cohesive zone 4B having a substantially conical shape is formed from the bosh section S4 toward the lower part of the shaft section S2 in the furnace.
An iron coritent 6A molten in the cohesive zone 4B passes through a dripping zone 4C, drips toward the blast furnace bottom section S6, and is accumulated in the blast furnace bottom section S6 as molten iron 6B. Coke or the like which has not been burned in the cohesive zone 4B drips through the dripping zone 4C, is stacked in the blast fiimace bottom section S6, and forms a conical furnace core 4D on the molten iron 6B.
The fiimace body 2 is provided with a taphole 6 in the blast fiimace bottom section S6, and the molten iron 6B accumulated in the blast furnace bottom section S6 is taken out outside the blast furnace 1 through the taphole 6.
[0025]
The fumace body 2 has an iron shell 2A in the outermost circumference, and a stave or firebrick 2D for cooling is affixed inside the iron shell 2A.
A stave 2B for a shaft is pasted in a region S7 facing the intermediate lumpy zone 4 A from the upper part of the shaft section S2. In the region S7, since the granular charged material 4 in the lumpy zone 4A sequentially descends while coming into contact with the surface of the stave 2B, mechanical abrasion may occur in the surface of the stave 2B.
[0026]

16 A stave 2C for a bosh section and a belly section is arranged in the inner
circumference of a region S8 including the belly section S3 and the bosh section S4 from
the lower part of the shaft section S2. In the region S8, the root portion 30 of the
cohesive zone 4B (a region where ore in the charged material starts to be softened and
molten, ores in a semi-molten state are fiised and connected into a plate shape, and there
are fluctuations up and down by operation) made of the high-temperature charged
material 4 sequentially descends while coming into contact with the regions S8.
Accordingly, damage and mechanical abrasion may occur in the surface of the stave 2C
inside the blast furnace 1 due to high temperature.
If necessary, the firebrick 2D is affixed to the inner surface of the blast furnace 1 corresponding to the staves 2B and 2C. Firebrick 2E is stacked thick in the blast furnace bottom section S6 where high-temperature molten iron is retained.
The region S8 from the lower part of the shaft section S2 of the blast furnace 1 over the belly section S3 and the bosh section S4 comes into contact with the root portion 30 of the cohesive zone 4B. Accordingly, heat loads in the blast furnace 1 are particularly high, and a portion of the firebrick 2D provided in the inner surface of the blast ftimace 1 corresponding to the stave 2C disappears in the comparatively early years of the fiimace life, about two to three years from blowing-in.
[0027]
In this embodiment, as the stave 2C provided in each of the bosh section S4 and the belly section S3 shown in FIG. 1, the stave 10 of this embodiment shown in FIG. 2 is used.
It is particularly preferable that the stave 10 (hereinafter, simply referred to as the stave 10) of this embodiment provided in each of the bosh section S4 and the belly section S3 is pasted in the bosh section S4 and the belly section S3 in the region S8 from

17 the lower part of the shaft section S2 of the blast ftimace 1 shown in FIG. 1 over the belly
section S3 and the bosh section S4. In FIG. 2, on the basis of the shape of the bosh
section S4, the upper end of the bosh section S4 is inclined from the center of the blast
fiamace 1 toward the outside of the blast furnace 1, and the lower end of the bosh section
S4 is inclined from the center of the blast furnace 1 toward the inside of the blast furnace
1.
[0028]
In this embodiment of FIGS. 2, 3, 4A, 4B, and 5, the stave 10 includes a copper or copper-alloy stave body 11 which has the reference surface R facing the internal space of the blast furnace 1, and a plurality of protrusions 12 which protrude from the reference surface R toward the inside of the blast furnace 1. The stave 10 may be made of a casting which is casted using copper or copper alloy in a bulk manner.
The stave body 11 has a thin plate shape cut from a copper or copper-alloy plate material.
As shown in FIG. 4 A, a plurality of protrusions 12 are provided continuously in a horizontal direction in the surface of the stave body 11. FIG. 4 A is a diagram showing a state where grooves 21 are not shown. As shown in FIG. 2, a plane 13 one level below is formed between a plurality of protrusions 12. As shown in FIGS. 2 and 3, three grooves 21 are formed in the plane 13, and firebrick 15 is fitted into the grooves 21. A refractory material 13Ais provided in concave portions 22 formed by the plane 13 and the protrusions 12.
Instead of the firebrick 15, refractory castable may be used. The number of grooves 21 and the locations are not limited thereto.
The plane 13 is formed through cutting from the surface of the stave body 11, and the protrusions 12 are formed to be cut and left during cutting. The plane 13 is the

18 reference surface R of the stave 10, and the protrusions 12 protrude from the reference
surface R of the stave 10.
[0029]
When the stave 10 is affixed in the blast furnace 1, as shown in FIG. 4A, the protrusions 12 is provided continuously along the circumferential direction in the blast furnace 1, and in the blast furnace 1, the protrusions 12 of the stave 10 are formed in a complete ring shape.
As shown in FIG. 4B, the protrusions 12 may be arranged intermittently (discontinuously) along the circumferential direction in the blast furnace 1. In this case, although various geometric patterns, such as a lattice pattern and a zigzag pattern, may be used, a point-symmetrical structure taking into consideration the circumference balance is preferably used. FIG. 4B is a diagram showing a state where grooves 21 are not shown.
As shown in FIG. 2, bolt receiving portions 11A for mounting in the blast furnace 1 are formed in the rear surface of the stave body 11.
[0030]
As shown in FIG. 2, the stave 10 includes a stave body cooling duct (stave body cooling channel) 16 which is provided inside the stave body 11 and through which a fluid for cooling the stave body 11 flows, and protrusion cooling ducts (protrusion cooling channels) 17 which are provided inside the protrusions 12 and through which a fluid for cooling the protrusions 12 flows.
Connection ports 16 A which are connected to the stave body cooling duct 16 are provided in the rear surface of the stave body 11, and connection ports 17A which are connected to the protrusion cooling ducts 17 are provided.
The stave body cooling duct 16 is arranged along the plane 13 in the

19 circumferential direction and the height direction of the blast furnace 1, such that the
plane 13 as the reference surface R of the stave 10 for the bosh section S4 and the belly
section S3 can be cooled by cooling water supplied from the connection ports 16A.
As shown in FIG. 3, the protrusion cooling ducts 17 are arranged to be inserted into the protrusions 12 along the circumferential direction in the blast furnace 1, such that the protrusions 12 can be cooled by cooling water supplied from the connection ports 17 A.
[0031]
It is preferable that a front end surface 12a of each protrusion 12 is coated with a TiN, Tie, WC, or Ti-Al-N-based high-hardness material.
A distance D between adjacent protrusions 12 is in the range of 500 to 1000 mm.
If the distance D between adjacent protrusions 12 is greater than 1000 mm, an accretion 19 which is produced starting with the protrusion and attached may not be produced and attached in the vicinity of the lower end of the protrusion at the high position. For this reason, it is difficult to form an accretion layer (accretion) at a predetermined thickness evenly over the entire reference surface R between adjacent protrusions, making it difficult to sufficiently obtain a self-lining effect of protecting the stave body against heat loads and wear in the root portion 30 of the cohesive zone 4B.
If the distance D between adjacent protrusions 12 is smaller than 500 mm, the charged material 4 which descends between adjacent protrusions and includes ores in a semi-molten state is reduced in rate, and the accretion layer which is produced on the reference surface R during cooling excessively increases in thickness. If the accretion layer is produced to an excessive thickness, the accretion layer interferes with stable descent of the charged material 4. When the accretion layer peels off due to changes in

20 the operating conditions of the blast furnace, or the Uke, this causes significant changes
in the furnace profile of the bosh section S4 and the belly section S3. Accordingly, it is
undesirable for maintaining stable operation of the blast furnace.
[0032]
In the bosh section S4, the protrusions 12 are provided such that the relation between a protrusion amount El from the reference surface R and a distance Dl between each protrusion 12 and another adjacent protrusion 12 satisfies Expression (A). In the belly section S3, the protrusions 12 are provided such that the relation between a protrusion amount E2 from the reference surface R and a distance D2 between each protrusion 12 and another adjacent protrusion 12 satisfies Expression (B). Dl=Elxtan[90°-(al-ei)] ... (A) D2=E2xtan(e2)=E2xtan[9O°-(a2-02)] ...(B)
[0033]
9 (Gl, 02) is the inclination angle of the accretion attached to the reference surface R. At present, the general charged material 4 includes an ore-based charged material having a particle size of 8 to 25 mm and a coke-based charged material having a particle size of 20 to 55 mm which are alternately charged into the blast fiimace. In the bosh section S4 which is provided in the vicinity of the root portion 30 of the cohesive zone 4B of the charged material 4 including ores in a semi-molten state, the inclination angle 01 of the accretion 19 attached to the reference surface R of the stave 10 is substantially constant at 75°. al is the inclination angle of the bosh section S4 of the blast furnace, and in the usual blast furnace 1, is designed to be in a range of 77 to 82°.
The protrusions 12 are provided such that the protrusion amounts El and E2 and the distances Dl and D2 satisfy the relations defined by Expressions (A) and (B), such

21 that the charged material 4 which descends inside the blast furnace 1 and includes ores in
a semi-molten state is reduced in rate, cooled, and attached to the reference surface R.
Therefore, it is possible to efficiently coat the entire reference surface R with a naturally
growing accretion layer, and to sufficiently protect the stave body against heat loads and
wear.
[0034]
The protrusions 12 are provided such that the protrusion amounts El and E2 and the distances Dl and D2 satisfy the relations defined by Expressions (A) and (B), such that it is possible to prevent an accretion layer from growing at an excessive thickness on the reference surface R. When the accretion layer peels off due to changes in the operating conditions of the blast furnace 1, or the like, it is possible to prevent significant changes in the furnace profile of the blast furnace 1 of the bosh section S4 and the belly section S3, and to avoid trouble relating to the operation, such as deterioration of the descent of the charged material 4 during a blast furnace operation, making it possible to maintain stable operation of the blast furnace for a long period of time.
The protrusion amounts El and E2 of the protrusions 12 are as follows. That is, the distances Dl and D2 between adjacent protrusions 12 of the stave for the bosh section and the stave for the belly section are set in the range of 500 to 1000 mm which is the desirable distance between the protrusions 12. The protrusion amounts El and E2 of the protrusions 12 are calculated by Dl and D2, Expression (A), and Expression (B).
Since the protrusions 12 protrude from the reference surface R toward the inside of the blast furnace 1, the protrusions 12 are likely to be worn due to damage or mechanical abrasion caused by extreme heat from the high-temperature charged material 4. For this reason, from the viewpoint of the balance between the wear rate of the protrusions 12 by the high-temperature charged material 4 and the growth rate of the

22 accretion on the reference surface R by the protrusions 12, in order to sufficiently exhibit
a durability improvement effect with self-lining of the stave body, it is preferable that the
protrusion amounts El and E2 of the protrusions 12 in both the stave 10 of the bosh
section S4 and the stave 10 of the belly section S3 from the reference surface R are in the
range of 50 to 150 mm.
[0035]
Firebrick 13A is provided in the concave portions 22 between the protrusions 12. The firebrick 13 A is used to protect the reference surface R of the stave 10 in each of the bosh section S4 and the belly section S3 from heat shock during a high-fuel-ratio (high-heat-load) operation during bio wing-in of the blast furnace 1. The firebrick 13 A may usually disappear due to damage or mechanical wear caused by heat shock in the early years, about two or three years from blowing-in.
In the bosh section and the belly section of the blast furnace of the related art, in a period of single refractory life from blowing-in to blowing-out of the blast furnace, when the furnace profile rapidly changes because the firebrick and the stave are damaged and worn due to extreme heat in the root portion 30 of the cohesive zone 4B, stable operation of the blast furnace becomes difficult.
[0036]
In contrast, in this embodiment, the stave 10 has the copper or copper-alloy stave body 11 having high heat conductivity and high heat flux capability, and the protrusions 12 which protrude from the reference surface R toward the inside of the blast furnace 1, and the stave 10 is provided in the inner circumference of each of the bosh section S4 and the belly section S3. In particular, the stave 10 is provided in a region of each of the bosh section S4 and the belly section S3 exposed to high temperature by the root portion 30 of the cohesive zone. Accordingly, even if the firebrick 13 A disappears

23 in the comparatively early years of the fiimace life, about two or three years from
blowing-in, it is possible to produce the accretion layer made of the charged material 4
on the reference surface R early, and to reduce changes of the furnace profile. With the
self-lining effect when producing an appropriate accretion on the surface of the stave 10
inside the blast fiimace 1 early, it becomes possible to extend the life of the bosh section
and the belly section contributing to the furnace life in the related art while maintaining
stable operation for a long period of time.
[0037]
As shown in FIG. 6, a plurality of stave body temperature sensors (stave body temperature detection units) 91a, 91b, and 91c are arranged along the reference surface R inside the stave body 11, and a protrusion temperature sensor (protrusion temperature detection unit) 92 is arranged inside each protrusion 12.
The blast furnace 1 includes an accretion estimation unit 95 which estimates the thickness of the accretion from the reference surface R of the stave body 11 and the residual thickness of the stave body 11 on the basis of the temperatures detected by the stave body temperature sensors 91a to 91c and the protrusion temperature sensor 92.
The stave body temperature sensors 91a to 91c are embedded in the plane 13 as the reference surface R of the stave 10 of each of the bosh section S4 and the belly section S3 along the height direction of the blast furnace 1. Outputs TW1, TW2, and TW3 from the stave body temperature sensors 91a to 91c are output to the outside, and the temperature TW (for example, as the average value of the outputs or variation in the average value) of the plane 13 is obtained.
The protrusion temperature sensor 92 is embedded in the protrusion 12, and an output TL is output to the outside. The outputs TW (TWl, TW2, and TW3) and TL are connected to a control device 94 of the blast furnace 1 through an interface 93 placed

24 outside the blast furnace 1. The accretion determination unit 95 is incorporated in the
control device 94, and determines the state of the accretion on the reference surface R of
the stave body 11 in the bosh section S4 and the belly section S3 on the basis of the
temperatures from the stave body temperature sensors 91a to 91c and the protrusion
temperature sensor 92.
It should suffice that the stave body temperature sensors 91a to 91c and the protrusion temperature sensor 92 are provided in the stave 10 of either the bosh section S4 or the belly section S3.
[0038]
The stave body temperature sensors 91a to 91c (TW=TW1, TW2, and TW3) are embedded on the lower side of the plane 13 as the reference surface R of the stave 10 in each of the bosh section S4 and the belly section S3. As shown in FIG. 8, in a state where the accretion 19 is deficient, the temperature in the blast fiimace 1 is detected sensitively at a high temperature. Meanwhile, as shown in FIGS. 9 and 10, if the accretion 19 grows on the plane 13, the protrusion 12 is covered with the accretion 19, such that the detection temperature is gradually transited to a low-temperature side and the variation in the detection temperature is detected insensitively.
The temperature sensor 92 (TL) is embedded in the fi"ont end surface of the protrusion 12. As shown in FIG. 8, in a state where the accretion 19 is deficient or as shown in FIG. 9, in a state where the protrusion 12 is not covered with the accretion 19, the temperature in the blast furnace 1 is detected sensitively at a high temperature. Meanwhile, as shown in FIG. 10, when the accretion 19 grows and covers the protrusion 12, the detection temperature is gradually transited to a low-temperature side and the variation in the detection temperature is detected insensitively.
[0039]

25 Next, a method of operating the blast furnace 1 will be described with reference
to a flowchart of FIG. 11.
First, the temperature of the stave body 11 and the temperature of the protrusion 12 are detected by the stave body temperature sensors 91a to 91c and the protrusion temperature sensor 92 (S11: temperature detection step).
Next, it is determined whether or not the thickness of the accretion 19 and the residual thickness of the stave body 11 estimated by the accretion estimation unit 95 are smaller than a predetermined value (S12: accretion determination step). That is, the accretion determination unit 95 monitors the outputs from the temperature sensors 91a to 91c and 92, and determines the production state of the accretion 19 on the basis of the temperatures TW (TWl, TW2, and TW3) and TL from the temperature sensors 91a to 91c and 92. The predetermined value is the thickness from the plane 13 shown in FIG. 9 to a position indicated by a two-dot-chain line, and in this embodiment, the depth of the concave portion 22 of the stave 10.
A specific determination method in the accretion determination unit 95 will be described with reference to FIG. 7.
In a time zone Al, the detection temperatures TW (TWl, TW2, and TW3) and TL are both high. Accordingly, the accretion determination unit 95 determines a state (the state of FIG. 8) where the accretion 19 is deficient, that is, smaller in thickness than the predetermined value (S12-1).
In a time zone A2, while the detection temperature TL makes sensitive movement (variation range WL, WWl, WW2, WW3) at a high temperature, the detection temperature TW (TWl, TW2, and TW3) is gradually or sequentially transited to a low-temperature side. In this case, the accretion determination unit 95 determines an appropriate state (the state of FIG. 9) where the accretion 19 has grown smoothly

26 (SI 2-2). Thereafter, the temperature of the stave body 11 and the temperature of the
protrusion 12 are measured again (Sll).
In FIG. 9, the appropriate state of the accretion 19 corresponds to a state (a transition state to an optimum state after the middle of the period A2) indicated by a solid line to a state (a most appropriate sate at the end of the period A) indicated by a two-dot-chain line. As shown in FIG. 7, the optimum state used herein refers to a period from the time tl at which the temperature TW3 detected by the stave body temperature sensor 91c starts to fall to the time t2 at which the temperature TL detected by the protrusion temperature sensor 92 starts to fall.
In a time zone A3, the detection temperature TL gradually decreases to a low-temperature side, and makes insensitive movement at a lower temperature (variation range WL'). Therefore, in this case, all the detection temperatures TW (TWl, TW2, and TW3) and TL are in a very insensitive state (variation range WL', WWl', WW2', and WW3') at a low temperature. Accordingly, the accretion determination unit 95 determines a state (the state of FIG. 10) where the accretion 19 is excessive, that is, greater in thickness than the predetermined value (S12-3).
[0040]
When the accretion 19 is deficient (SI2-1), the combustion temperature in the blast furnace 1 or the temperatures of the stave body 11 and the protrusion 12 are controlled such that the accretion 19 grows. Specifically, cooling of the stave 10 is enhanced with an increase in the flow rate of cooling water, or the operating conditions or the charged material distribution are adjusted to decrease the temperature in the furnace (S13: temperature control step).
Meanwhile, when it is determined that the accretion 19 is excessive (S12-3), the combustion temperature in the blast furnace 1 or the temperatures of the stave body 11

27 and the protrusion 12 are controlled such that the accretion 19 decreases. Specifically,
cooling of the stave 10 in each of the bosh section S4 and the belly section S3 is modified,
or the operating conditions or the charged material distributed are adjusted to increase the
temperature in the blast furnace 1 (S13: temperature control step).
After temperature control, the temperature of the stave body 11 and the temperature of the protrusion 12 are measured again (Sll).
[0041]
In FIG. 9, at present, the general charged material 4 includes an ore-based charged material having a particle size of 8 to 25 mm and a coke-based charged material having a particle size of 20 to 55 mm which are alternately charged into the blast fiimace. In the stave 10 which is provided in the bosh section S4 in the vicinity of the root portion 30 of the cohesive zone 4B made of the charged material 4 including ores in a semi-molten state, it is confirmed that, when the accretion 19 grows smoothly, the inclination angle 91 of the accretion 19 attached to the reference surface R is about 75°. Meanwhile, while the previous actual blast fiimace examination result shows that, with the occurrence of a large amount of powder due to disintegration during reduction of the charged material state or the like or changes in pressure on the charged material side due to the fiimace body profile, it is difficult to confirm the inclination angle 92 of the accretion 19 in stave 10 of the belly section S3, it is supposed that the inclination angle 02 is in the range of about 85° to 88°.
[0042]
The state of the accretion 19 is determined by the accretion determination unit 95, and a step based on the determination result is performed, thereby forming a desired layer of the accretion 19 in the stave 10. That is, an operator of the blast furnace 1 can perform operational adjustment such that a coating necessary for protecting the stave 10

28 in each of the bosh section S4 and the belly section S3 is formed in the stave 10.
[0043]
According to this embodiment described above, the following effects are obtained.
The stave 10 which is provided in each of the bosh section S4 and the belly section S3 arranged particularly in a region exposed to the root portion 30 of the cohesive zone 4B in the irmer surface of the blast furnace 1 includes the copper or copper-alloy stave body 11 which has the plane 13 inside the blast furnace 1 as the reference surface R, and the protrusions 12 which protrude from the reference surface toward the inside of the furnace. Accordingly, the root portion 30 of the cohesive zone 4B of the charged material 4 descending inside the blast furnace 1 and including ores in a semi-molten state is reduced in rate and cooled, and the accretion 19 grows along the reference surface R. Therefore, it is possible to coat the reference surface R with the accretion 19.
As a result, the accretion 19 serves as a protective layer, and the reference surface R is not directly exposed to the root portion 30 of the high-temperature cohesive zone 4B, thereby increasing heat resistance as the stave 10 in the bosh section S4 and the belly section S3.
[0044]
In particular, in this embodiment, the copper or copper-alloy stave body 11 having high heat conductivity and high heat flux capability is used. Accordingly, even if the coating of the reference surface R peels off due to changes in the operating conditions of the blast furnace 1, or the like, the charged material 4 which subsequently descends and includes ores in a semi-molten state is reduced in rate. The charged material 4 is rapidly cooled and attached to the reference surface R, thereby reproducing the coating layer of the accretion 19 early. With the self-lining effect using the

29 accretion 19, ample durability is obtained as the stave 2C (10) in the bosh section S4 and
the belly section S3.
[0045]
In the stave 10 of the bosh section S4 and the belly section S3, the protrusion cooling duct 17 is also formed in the protrusion 12 along with the stave body cooling duct 16 formed inside the stave body 11. In the stave 10 of this embodiment in the bosh section S4 and the belly section S3, since the stave body 11 is made of copper or copper alloy having high heat conductivity and high heat flux capability, the protrusion is sufficiently cooled only by the stave body cooling duct 16 inside the stave body 11. Meanwhile, if the protrusion cooling duct 17 is also formed in the protrusion 12 to directly cool the protrusion 12, the temperature of the reference surface R of the stave body 11 decreases, thereby further promoting the production of the accretion 19.
[0046]
In the stave 10 of the bosh section S4 and the belly section S3, the temperature sensors 91a to 91c and 92 are provided in the plane 13 as the reference surface R and a portion of the protrusion 12, and the thickness of the accretion 19 and the residual thickness of the stave body 11 are estimated by the accretion determination unit 95, thereby determining integrity of the furnace profile outside the blast furnace 1.
The cooling state of the stave 10 of the bosh section S4 and the belly section S3 or other parameters is adjusted on the basis of the determination result by the accretion determination unit 95. Accordingly, it is possible to achieve appropriate growth of the accretion 19. In this way, the thickness of the accretion layer on the reference surface R of the stave body 11 is appropriately adjusted, thereby protecting the stave body against heat loads and wear and preventing deterioration of the furnace profile due to excessive growth of the accretion 19. With the maintenance of an appropriate profile, it is

30 possible to stabilize a blast furnace operation.
[0047]
In the stave 10 of the bosh section S4 and the belly section S3, the distance between adjacent protrusions 12 is in the range of 500 to 1000 mm.
If the distance between adjacent protrusions 12 is greater than 1000 mm, the accretion 19 which is produced starting with the protrusion 12 and attached may not be produced and attached in the vicinity of the lower end of the protrusion 12 at the high position. For this reason, it is difficult to form the accretion layer at a predetermined thickness evenly over the entire reference surface R between adjacent protrusions 12, making it difficult to sufficiently obtain a self-lining effect of protecting the stave body 11 against heat loads and wear by the root portion 30 of the cohesive zone 4B. Meanwhile, in the stave 10 of this embodiment, in the bosh section S4 and the belly section S3 in which the distance between adjacent protrusions 12 is in the range of 500 to 1000 mm, it is possible to avoid this problem.
[0048]
If the distance between adjacent protrusion 12 is smaller than 500 mm, the charged material 4 which descends between adjacent protrusions 12 and includes ores in a semi-molten state is reduced in rate, and the accretion layer which is produced on the reference surface R during cooling excessively increases in thickness. If the accretion layer is produced at an excessive thickness, the accretion layer interferes with stable descent of the charged material 4. When the accretion layer peels of due to changes in the operating conditions of the blast furnace 1, or the like, this causes significant changes of the furnace profile of the bosh section S4 and the belly section S3. Accordingly, it is undesirable for maintaining stable operation of the blast fiimace. Meanwhile, in the stave 10 of this embodiment in the bosh section S4 and the belly section S3 in which the

31 distance between adjacent protrusions 12 is in the range of 500 to 1000 mm, it is possible
to avoid this problem.
[0049]
In the stave 10 of the bosh section S4 and the belly section S3, the protrusions 12 of the stave 10 of the bosh section S4 are provided such that the relation between'the protrusion amount El from the reference surface R and the distance Dl between adjacent protrusions 12 satisfies Expression (A). The protrusions 12 of the stave 10 of the belly section S3 are provided such that the relation between the protrusion amount E2 from the reference surface R and the distance D2 between adjacent protrusions 12 satisfies Expression (B).
Dl=Elxtan[90°-(al-e2)] ... (A) D2=E2xtan(e2)=E2xtan[90°-(a2-e2)] ...(B)
[0050]
G (91, 92) is the inclination angle of the accretion attached to the reference surface R. At present, the general charged material 4 includes an ore-based charged material having a particle size of 8 to 25 mm and a coke-based charged material having a particle size of 20 to 55 mm which are alternately charged into the blast furnace 1. The inclination angle 9 of the stave 10 of the bosh section S4 in the vicinity of the root portion 30 of the cohesive zone 4B of the charged material 4 including ores in a semi-molten state is substantially constant at 75°. In this case, al is the inclination angle of the bosh section S4 of the blast furnace, and in the usual blast furnace 1, al is designed in the range of 77 to 82°. The inclination angle 92 of the stave 10 of the belly section S3 is empirically estimated to be about 85 to 88°, and the inclination angle a2 of the belly section S3 is designed to be constant at 90°.

32 Since the protrusions 12 are provided such that the protrusion amounts El and
E2 and the distances Dl and D2 satisfy the relations defined by Expressions (A) and (B),
the charged material 4 which descends inside the blast furnace 1 and includes ores in a
semi-molten state is reduced in rate. Accordingly, the charged material 4 is cooled and
attached to the reference surface R, thereby efficiently coating the entire reference
surface R with a naturally growing accretion layer and sufficiently protecting the stave
body 11 against heat loads and wear.
[0051]
The protrusions 12 are provided such that the protrusion amounts El and E2 and the distances Dl and D2 satisfy the relations defined by Expressions (A) and (B). Accordingly, when the accretion layer grows at an excessive thickness on the reference surface R, and the accretion layer peels off due to changes in the operating conditions of the blast furnace, or the like, it is possible to prevent deterioration of the profile of the inner surface of the blast fiimace 1 in the bosh section S4 and the belly section S3, and to avoid trouble relating to the operation, such as deterioration of the descent of the charged material 4 during a blast fiimace operation, making it possible to maintain stable operation of the blast furnace for a long period of time.
When the distances Dl and D2 between adjacent protrusions of the stave 10 in the bosh section S4 and the stave 10 in the belly section S3 are set in the range of 500 to 1000 mm which is the desirable distance between the protrusions 12, the protrusion amounts El and E2 of the protrusions 12 are set from Dl and D2 and Expressions (A) and (B).
Since the protrusions 12 protrude from the reference surface R toward the inside of the furnace, the protrusions 12 are likely to be worn due to heat from the high-temperature charged material 4 or abrasion. For this reason, from the viewpoint of

33 the balance between the wear rate of the protrusions 12 by the high-temperature charged
material 4 and the growth rate of the accretion on the reference surface R by the
protrusions 12, in both the stave 10 of the bosh section S4 and the stave 10 of the belly
section S3, it is desirable that the protrusion amounts El and E2 of the protrusions 11
from the reference surface R are 50 to 150 mm. In this way, if the protrusion amounts
El and E2 are adjusted, it is possible to sufficiently exhibit the durability improvement
effect with the self-lining effect of the stave body 11.
[0052]
Since the protrusions 12 have a surface coating using a high-hardness material, it is possible to prevent the protrusions 12 itself from being abraded. Accordingly, it is possible to stably maintain durability performance for a long period of time as the stave 10 of the bosh section S4 and the belly section S3.
Since the protrusions 12 are formed integrally with the stave body 11, manufacturing of the protrusions 12 is facilitated. Processing is also simplified for the formation the protrusion cooling duct 17 in the protrusion 12.
Since the firebrick 13A is provided in the concave portion 22 between the protrusions 12, it becomes easy to endure heat shock (high-fuel-ratio operation) during blowing-in of the blast furnace 1 in which the accretion 19 does not grow. Moreover, in a period of single refractory life of about 15 years from blowing-in to blowing-out of the blast furnace, even after the firebrick 13 A disappears due to damage or mechanical wear caused by heat shock in the comparatively early years, about two or three years from blowing-in, the layer of the accretion 19 in which the charged material 4 is attached to the reference surface R of the stave body 11 is produced early. With the accretion layer, it becomes possible to protect the stave body 11 against heat loads and wear by the root portion 30 of the cohesive zone 4B (self-lining effect), making it possible to perform

34 stable operation for a long period of time.
[0053]
In this embodiment, the stave 10 of the bosh section S4 and the belly section S3 is used as the stave 2C, thereby increasing heat shock resistance and abrasion resistance with the self-lining effect on the reference surface R of the stave body 11.
In particular, the stave 10 of this embodiment in the bosh section S4 and the belly section S3 is arranged as the stave 2C of the region S8 from the lower part of the shaft section S2 of the blast furnace 1 over the belly section S3 and the bosh section S4. Accordingly, when the root portion 30 of the cohesive zone 4B made of the high-temperature charged material 4 in the cohesive zone 4B sequentially descends while coming into contact with the surface of the stave 2C, with the protrusions 12 of the stave 10 of the bosh section S4 and the belly section S3, the accretion 19 is reduced in rate. In this way, the accretion 19 is rapidly cooled, and the coating of the accretion layer is formed on the reference surface R early.
Accordingly, even after the firebrick provided inside the blast furnace 1 disappears due to damage or mechanical wear caused by heat shock in the comparatively early years of the furnace life, about two or three years from blowing-in of the blast furnace 1, the accretion layer is formed on the reference surface R, thereby suppressing the transmission of the high temperature from the cohesive zone 4B to suppress damage and wear to the reference surface R.
[0054]
That is, in the region S8 with which the root portion 30 of the cohesive zone 4B made of the high-temperature charged material 4 comes into contact, the firebrick is damaged and worn due to extreme heat in the comparatively early years of the furnace life, about two or three years from blowing-in of the blast furnace 1, and the furnace

35 profile undergoes rapid changes, making it difficult to perform stable operation of the
blast furnace 1. In contrast, in the blast furnace 1 of this embodiment, the stave 10
including the copper or copper-alloy stave body 11 having high heat conductivity and
high heat flux capability and the protrusions 12 protruding from the reference surface R
toward the inside of the furnace are provided, in particular, in a region exposed to high
temperature by the root portion 30 of the cohesive zone 4B in the bosh section S4 and the
belly section S inside the blast fiimace 1. Accordingly, even if the firebrick inside the
blast furnace 1 disappears in the comparatively early years of the furnace life, about two
or three years from blowing-in of the blast furnace 1, it is possible to produce the
accretion layer earlier on the reference surface R for the remaining ten years or more.
In this way, the accretion layer is stably maintained to reduce changes in the furnace
profile, thereby stably performing the operation of the blast furnace 1 for a long period of
time and considerably extending the life of the blast furnace 1.
[0055]
In the blast furnace 1, the protrusions 12 of the stave 10 in the bosh section S4 and the belly section S3 arranged inside the blast furnace 1 are provided continuously in the entire circumference of the blast furnace 1, making it easy to appropriately maintain the circumference balance of the blast furnace 1. It is possible to satisfactorily maintain the operation of the blast furnace 1.
Since the blast furnace 1 has the accretion determination unit 95 in the control device 94, it is possible to determine the state of the accretion 19 on the basis of the detection temperatures TW (TWl, TW2, and TW3) and TL from the temperature sensors 91a to 91c and 92 of the stave 10 in the bosh section S4 and the belly section S3. The control device 94 adjusts the operation state of the blast furnace 1 with reference to the determination result, thereby obtain an appropriate coating on the reference surface R of

36 the stave body 11.
[0056] [Second Embodiment]
FIGS. 12, 13, and 14 show a second embodiment of the invention.
A stave 20 of this embodiment for a bosh section and a belly section is used as the stave 2C of the region S8 from the lower part of the shaft section S2 over the belly section S3 and the bosh section S4 in the blast fiamace 1 of the foregoing first embodiment. The configuration of the blast furnace 1 is the same as in the foregoing first embodiment, and the stave 20 of this embodiment in the bosh section S4 and the belly section S3 has the same basic configuration as the stave 10 of the foregoing first embodiment in the bosh section S4 and the belly section S3. Accordingly, the same parts as those of the stave 10 of the foregoing first embodiment will not be described, and only different parts will be described here.
In FIGS. 12, 13, and 14, the stave 20 in the bosh section S4 and the belly section S3 includes a stave body 11, bolt receiving portions 11 A, protrusions 12, plane 13, firebrick 15, a stave body cooling duct 16, and cormection ports 16A which are the same as those in the stave 10 of the foregoing first embodiment in the bosh section S4 and the belly section S3. In the stave 10 of the foregoing first embodiment, the protrusion cooling duct 17 formed inside each protrusion 12 and the connection ports 17A are not shown.
[0057]
In this embodiment, it is possible to obtain the same effects as in the foregoing first embodiment. Since there is no protrusion cooling duct 17 formed inside each protrusion 12, local cooling of the protrusions 12 is not obtained.
From this point, in the stave 10 of the foregoing first embodiment for a bosh

37 section and a belly section, local cooling of the protrusions 12 is obtained. Accordingly,
since temperature control around the protrusions 12 is effectively performed, it is best to
adjust the accretion 19. In the stave 20 of this embodiment for a bosh section and a
belly section, since there is no protrusion cooling duct 17, it is possible to simplify the
structure and to reduce manufacturing costs as much. It can be said that it is preferable
to use the stave 20 of the second embodiment in a region, in which there is little demand
for adjustment of the accretion 19, on the reference surface of the stave body.
[0058] [Modifications]
The invention is not limited to the foregoing first and second embodiments, and includes modifications or the like within the scope capable of achieving the object of the invention.
The stave 10 or 20 of each embodiment in the bosh section S4 and the belly section S3 is provided in the bosh section S4 from the region S8 where the stave 2C is affixed. The stave body 11 is configured such that, on the basis of the shape of the bosh section S4, the upper end is inclined toward the outside of the fiimace and the lower end is inclined toward the inside of the furnace. The stave of the belly section S3 is applied to the belly section S3 from the region S8. For this reason, the stave body 11 is not inclined and the reference surface R is formed vertically on the basis of the belly section S3.
[0059]
Although in the foregoing embodiments, when the stave 10 or 20 of the bosh section S4 and the belly section S3 is arranged inside the blast furnace 1, the protrusions 12 of the stave 10 or 20 in the bosh section S4 and the belly section S3 are provided continuously in the circumferential direction of the blast furnace 1 in a ring shape, the

38 protrusions 12 may be in a discontinuous ring shape, or may be arranged in a zigzag
pattern at different heights or at sequentially changing heights. In the operation of the
blast furnace 1, the circumference balance is important, and it is necessary to take into
consideration such that symmetry is obtained relative to the center of the blast furnace 1.
[0060]
Although in the foregoing embodiments, the protrusions 12 of the stave 10 in the bosh section S4 and the belly section S3 are subjected to surface coating using a high-hardness material or the protrusions 12 itself are molded using a high-hardness material, it is not necessary to use a high-hardness material. Meanwhile, since the protrusions 12 protrude from the reference surface R of the stave body of the stave 10 or 20 and are likely to be abraded by the charged material 4, it is desirable to secure abrasion resistance using a high-hardness material.
In the foregoing embodiments, before the stave 10 or 20 is provided inside the blast furnace 1, protective firebrick may be pasted between the protrusions 12 to protect the reference surface R against heat shock during blowing-in.
The arrangement and sectional shape of the protrusions 12, the arrangement of the stave body cooling duct 16 and the protrusion cooling duct 17, and the installation positions of the temperature sensors 91a to 91c and 92, the number of the temperature sensors 91a to 91c and 92, the overall shape, dimension, and the like of the stave 10 or 20 in the bosh section S4 and the belly section S3 may be appropriately selected when implementation.
Although a configuration in which the grooves 21 are formed in the reference surface R of the stave 10 or 20 has been described, the grooves 21 may not be provided. That is, although a plurality of grooves 21 are formed in the reference surface R, making it possible to prevent heat inside the blast furnace 1 from escaping outside the blast

39 furnace 1, if there is no problem even if heat escapes outside, the grooves 21 may not be
provided.
Description of the Reference Symbols [0061]
1: blast furnace 2: furnace body 2A: iron shell 2B, 2C: stave 2D, 2E: firebrick 3: gas collection mantel 4: charged material 4A: lumpy zone 4B: cohesive zone 4C: dripping zone 4D: furnace core 5: tuyere 5A: hot blast 5B: raceway 6: taphole 6A: iron content 6B: molten iron 10,20: stave
11: copper or copper-alloy stave body 11 A: bolt receiving portion

40 12: protrusion
13: plane
15: firebrick
16,17: stave body cooling duct
16A, 17A: connection port
19: accretion
91 a to 91 c, 92: temperature sensor
93: interface
94: control device
95: accretion determination unit
D1,D2: distance
E1, E2: protrusion amount
R: reference surface
S1: throat section
S2: shaft section
S3: belly section
S4: bosh section
S5: tuyere section
S6: blast furnace bottom section
S7: installation region of stave for shaft
S8: installation region of stave for bosh section and belly section
TL, TW, TWl, TW2, TW3: detection temperature
9,61,62: inclination angle on inner surface of blast fiimace of accretion
attached to reference surface R
al, a2: angle of stave for bosh section and belly section

41 CLAIMS
1. A stave which is provided in an inner circumference of each of a bosh
section and a belly section of a blast fiimace, the stave comprising:
a copper or a copper-alloy stave body which has a reference surface facing an internal space of the blast furnace; and
a plurality of protrusions which protrude from the reference surface toward an inside of the blast furnace.
2. The stave according to claim 1, further comprising:
a cooling channel of a stave body which is provided inside the stave body and through which a fluid cooling the stave body flows; and
cooling channels of protrusions which are provided inside the protrusions and through which a fluid cooling the protrusions flows.
3. The stave according to claim 1, further comprising:
a plurality of stave body temperature detection units which are arranged along the reference surface inside the stave body; and
a protrusion temperature detection unit which is arranged inside each protrusion.
4. The stave according to claim 1,
wherein a distance between adjacent protrusions is in the range of 500 to 1000 mm.
5. The stave according to claim 4,

42 wherein, in the bosh section, the protrusions are provided such that a relation
between a protrusion amount El from the reference surface and a distance Dl between
each protrusion and another adjacent protrusion satisfies Expression (A), and
in the belly section, the protrusions are provided such that a relation between a protrusion amount E2 from the reference surface and a distance D2 between each protrusion and another adjacent protrusion satisfies Expression (B): Dl = El X tan[90° - (al - 61)] ... (A) D2 = E2 X tan(e2) = E2 x tan[90° - (a2 - 62)] ... (B)
wherein, 91 is 75° which is an inclination angle of an accretion attached to the reference surface in the bosh section,
62 is 85° to 88° which is an inclination angle of an accretion attached to the reference surface in the belly section,
al is 77° to 82° which is an inclination angle of the stave used in the bosh section, and
a2 is 90° which is an inclination angle of the stave used in the belly section.
6. The stave according to claim 1,
wherein the protrusions are provided continuously or intermittently in a circumferential direction inside the blast furnace.
7. The stave according to claim 1,
wherein a plurality of grooves are formed in the reference surface.
8. The stave according to claim 7,

43 wherein a refractory material is provided in concave portions that are formed by
the reference surface and the protrusions, and the grooves.
9. A blast furnace comprising:
the stave according to any one of claims 1 to 8.
10. The blast furnace according to claim 9, wherein:
a plurality of stave body temperature detection units arranged along the reference surface and the protrusion temperature detection unit arranged inside each protrusion are provided inside the stave body of either the stave used in the bosh section or the stave used in the belly section; and
the blast furnace further comprises an accretion estimation unit which estimates a thickness of an accretion from the reference surface of the stave body and a residual thickness of the stave body based on temperatures detected by the stave body temperature detection units and the protrusion temperature detection unit.
11. A blast furnace operation method which operates the blast fiimace
according to claim 10, the blast furnace operation method comprising:
a temperature detection process which detects temperatures of the stave body and the protrusions by the stave body temperature detection units and the protrusion temperature detection unit;
an accretion determination process which determins whether or not the thickness of the accretion and the residual thickness of the stave body estimated by the accretion estimation unit are smaller than a predetermined value; and
a temperature control process which controUs a combustion temperature inside

44 the blast furnace or the temperatures of the stave body and the protrusions based on a
determination in the accretion determination step.
Dated this 07/05/2012 ( ^
(HWS™ESH(RAI^HAUDHURY) ' OFIIEIVWRY & SAGAR
ATTORNEY FOR THE |IPPLICANT[S]