WO2007100076A1

WO2007100076A1 - Rotary hearth

Info

Publication number: WO2007100076A1
Application number: PCT/JP2007/054005
Authority: WO
Inventors: Hiroshi Sugitatsu; Takao Umeki
Original assignee: Kabushiki Kaisha Kobe Seiko Sho
Priority date: 2006-03-03
Filing date: 2007-03-02
Publication date: 2007-09-07
Also published as: JP2007232334A; JP4069138B2

Abstract

A rotary hearth in which a foreign matter, e.g. material powder or refractory powder, entering a gap provided as an expansion allowance in the refractory of the rotary hearth can be removed easily, and the rotary hearth can be repaired easily. The rotary hearth comprises corner refractories (8, 9) arranged on the inner and outer circumferential sides, and a monolithic refractory (7) and expansion allowance blocks (11, 12) held between these corner refractories (8, 9) to constitute the hearth surface. A lower expansion allowance is provided between adjoining monolithic refractories (7), and recesses (17a, 17b) opening upward are formed in the upper part of each monolithic refractory (7) adjoining to the lower expansion allowance. The expansion allowance blocks (11, 12) are provided removably in respective recesses to straddle the lower expansion allowance, and upper expansion allowances (11a, 11b, 12a, 12b) are provided between the expansion allowance blocks (11, 12) and the inner circumferential surface of the recess in at least one monolithic refractory.

Description

Specification

Rotary hearth

Technical field

TECHNICAL FIELD [0001] The present invention relates to a fire hearth rotary hearth provided in a rotary hearth furnace. More specifically, the present invention relates to heating and reducing a carbonaceous material-containing workpiece comprising at least a metal oxide-containing material and a carbon-containing reducing material. The present invention relates to a rotary hearth of a rotary hearth furnace for producing reduced metal. Furthermore, this rotary hearth can also be applied to a rotary hearth furnace used for heating steel materials.

Background art

[0002] In recent years, the demand for reduced iron has been increasing as the production of steel materials by electric furnaces has become popular. This is due to the tight demand for scrap, which is the main raw material of the steel, and the demand for the production of high-grade steel in the electric furnace.

[0003] As one of the processes for producing the reduced iron, a step of mixing a powdered iron ore and a powdered coal or carbonaceous material such as coatas to produce an agglomerate, for example, a pellet or a plecket; A method including a step of charging the agglomerated material into a rotary hearth furnace and heating it to a high temperature to reduce iron oxide in the iron ore to produce solid metallic iron is attracting attention ( For example, JP-A-45-19569 and JP-A-11-279611).

Such a reduction method can be used not only for the production of metallic iron but also for the production of the non-ferrous metal by reduction of non-ferrous metal oxides such as Ni and Cr. In the following description, the production of metallic iron is taken as an example, but this does not mean that the present invention described in detail later is limited to the production of metallic iron. The present invention can also be applied to the production of other non-ferrous metals.

[0005] Next, an example of a method for producing reduced iron using a rotary hearth furnace will be described below with reference to FIG. FIG. 6 is a horizontal sectional view schematically showing a rotary hearth furnace for producing reduced iron. (1) Powdered iron oxide (iron ore, electric furnace dust, etc.) and powdered carbonaceous reductant (coal, cotas, etc.) are mixed and granulated. As a result, raw pellets or prickets (hereinafter collectively referred to as pellets) are produced. (2) These raw pellets are heated to a temperature range where combustible volatiles generated from the inside do not ignite as necessary. As a result, the water adhering to the raw pellets is removed, and the raw pellets become dry pellets. This step is unnecessary when the moisture of the raw pellets is low or when the drying is performed in a rotary hearth furnace.

(3) The raw pellets or dried pellets (raw material 20) are fed into the rotary hearth furnace 26 by using an appropriate charging device 23. Thereby, a pellet layer having a thickness of about 1 to 2 pellets is formed on the rotary hearth (hereinafter referred to as the hearth) 21.

(4) The pellet layer is reduced by radiant heating by combustion of the burner 27 installed in the upper part of the furnace. This reduction advances the metallization of the pellet layer.

(5) The metallized pellets are cooled by the cooler 28. As this cooling, cooling power by directly blowing gas onto the pellet or indirect cooling by a water cooling jacket is performed. After cooling, the pellets are discharged out of the furnace by the discharge device 22 after the mechanical strength that can withstand handling during and after discharge is developed.

(6) Immediately after discharging the metallized pellets (reduced iron 30), the next raw pellets or dried pellets (raw material 20) are charged. Thereafter, reduced iron is produced by repeating the above process.

Next, details of the above step (3) will be described in detail below with reference to FIG. FIG. 7 is a vertical sectional view showing a hearth structure of a rotary hearth furnace for producing reduced iron (hereinafter referred to as a rotary hearth furnace) according to a conventional example.

[0007] The rotary hearth furnace 1 includes a hood 33 including a ceiling 31 and inner and outer side walls 32, and an annular rotary hearth 10 disposed between the side walls 32. A large number of wheels 34 are attached to the lower part of the rotary hearth 10, and these wheels 34 are driven by a driving device (rotating at a constant speed on a track 35 circulated on the floor surface at a constant speed. (Not shown). Conversely, although not shown in the figure, the track is fixed to the bottom of the hearth 10 and wheels are arranged on the floor in a circular shape, and the drive device rotates the wheels at a constant speed. Sometimes.

A water sealing means 36 is provided between the rotary hearth 10 and the inner and outer side walls 32. This water The sealing means 36 is for blocking the atmosphere in the furnace from the outside air while allowing the rotary hearth 10 to freely rotate with respect to the hood 33. The water sealing means 36 shown in FIG. 7 includes an annular metal sealing trough 38. The seal trough 38 is provided along the lower inner surface of each side wall 32, and the seal trough 38 is filled with water 37. On the other hand, a cylindrical metal skirt 39 projecting downward is provided at the outer peripheral edge of the rotary hearth 10, and the bottom end of the skirt 39 is not in contact with the seal trough 38. Soaked in water 37.

[0009] Since the rotary hearth 10 is radiatively heated at a high temperature by the burner 42 installed in the hood 33 with the pellets 40 placed on the upper surface thereof, the hearth 10 has a refractory structure. 41 is adopted. The refractory structure 41 includes a heat-resistant refractory 41a constituting a lower layer portion and a heat-resistant refractory 41b constituting an upper layer portion laminated on the lower layer portion. Since the heating and cooling are repeated every short time (about 6 to 20 minutes) in the vicinity of the upper surface of the hearth 10 where the pellets 40 are placed, the refractory usually has spalling resistance. Is used.

[0010] In this rotary hearth furnace 1, there is a problem in that it is inevitable that powder foreign matter that also generates pellet 40 isotropic force is mixed with the pellet 40 into the furnace. The powder foreign matter is, for example, rolling of the pellet 40 itself when the pellet 40 is supplied to the rotary hearth 10, rubbing due to contact between the pellet 40 and the charging device, drop impact, explosion or fire resistance due to thermal shock. It occurs due to various factors, such as powder from the material, sand and mud brought in from the outside of the furnace during inspection. When the rotary hearth furnace 1 is cooled and the refractory 41 contracts, the powder foreign matter may enter a gap corresponding to the expansion margin of the heat-resistant refractory 41. When the rotary hearth furnace 1 rises in temperature again, the powder foreign matter that enters may inhibit the expansion of the refractory 41 and damage the refractory 41. When the refractory 41 was damaged, it was necessary to repair most of the refractory 41 on the 10th floor of the hearth, including removal of the powder foreign material that had entered the gap of the expansion margin.

[0011] Two conventional techniques proposed for solving such problems will be described below with reference to FIG. FIG. 8 is a partial plan view of the hearth of the rotary hearth furnace according to these conventional examples. [0012] In the first prior art, the inner portion of the annular rotary hearth 10 disposed between the inner peripheral wall and the outer peripheral wall of the rotary hearth furnace is formed of a refractory castable layer 55. . Further, a plurality of rows of fire bricks 73 and 74 are arranged at positions adjacent to the inner peripheral side and the outer peripheral side with respect to the fire resistant castable layer 55, respectively, and a predetermined interval is provided between the fire bricks 73 and 74. Gaps 57 and 58 are formed (see Patent Document 1). These gaps 57, 58 are capable of absorbing thermal expansion deformation of the refractory castable layer 55 and have a size capable of preventing small diameter pellets from entering the gaps 57, 58. Yes.

[0013] When the rotary hearth furnace is operated for a long time with a strong force, it is inevitable to generate fine powder foreign substances such as powder generated from the pellets or refractory release powder! Such fine powder can enter the gaps 57 and 58.

[0014] In the second prior art, the inner peripheral edge and the outer peripheral edge of the rotary hearth 10 shown in Fig. 8 are constituted by frame bodies 43, 44 formed by fireproof castable, and these frame bodies 43, 44 are respectively It is divided with predetermined gaps 51 and 52 at a plurality of locations in the circumferential direction. The gaps 51 and 52 are filled with a ceramic sheet or a ceramic blanket (see Patent Document 2).

[0015] However, even in the second prior art, when the rotary hearth furnace 1 is operated for a long period of time, a deviation of the furnace material due to the rolling of the rotary hearth 10, deterioration of the ceramic filler, etc. As a result, a gap may be formed in the gaps 51, 52, and fine powder may enter the gaps 51, 52. Like the above, this fine powder hinders the function of the expansion margin at the time of re-heating, and may cause damage to the refractory. If the refractory is damaged in this way, most of the refractory constituting the hearth 10 needs to be repaired.

Patent Document 1: Japanese Patent Laid-Open No. 2002-310565

Patent Document 2: JP-A-2002-310564

Disclosure of the invention

[0016] In view of the above circumstances, the object of the present invention is to remove a foreign material such as a raw material powder or a refractory powder that has entered a gap as an expansion margin provided in a refractory for a rotary hearth furnace. The object is to provide a rotary hearth that can be prepared and repaired. In order to achieve this object, a rotary hearth according to the present invention includes a hearth frame that is rotatably installed in the furnace of the rotary hearth furnace, an inner peripheral side portion and an outer periphery of the hearth frame. It on the side part A plurality of irregular refractories provided on the hearth frame between the inner peripheral corner refractories and the outer peripheral corner refractories disposed between the inner peripheral corner refractories and the outer peripheral corner refractories. An object and a plurality of expansion allowance blocks. A plurality of the irregular refractories are arranged in at least one of the radial direction and the circumferential direction of the rotation of the hearth frame, and among the irregular refractories, the irregular refractories adjacent to each other are arranged. The irregular refractory is disposed so that a lower expansion margin is provided therebetween, and is adjacent to the lower expansion margin and above the lower expansion margin of each irregular refractory. A recess is formed in the part and is opened upward. The expansion allowance block has at least one of the expansion allowance block and the expansion allowance block straddling the lower expansion allowance in the recesses of the adjoining irregular shape refractories among the irregular shape refractories. It is detachably mounted so as to secure an upper expansion margin between the inner peripheral surface of the concave portion of the irregular refractory.

Brief Description of Drawings

FIG. 1 is a partial vertical sectional view showing a hearth structure of a rotary hearth furnace according to an embodiment of the present invention.

2 is a partial detailed cross-sectional view showing an enlarged portion A of FIG.

FIG. 3 is a partial plan view of a part of the rotary hearth 10 of FIG.

4 is a partial detailed cross-sectional view showing an enlarged view B-B in FIG.

FIG. 5 is a construction procedure diagram in which a partial surface layer of the hearth according to the embodiment of the present invention is viewed in cross section.

FIG. 6 is a horizontal sectional view schematically showing a rotary hearth furnace for producing reduced iron according to a conventional example.

FIG. 7 is a vertical sectional view showing a hearth structure of a rotary hearth furnace for producing reduced iron according to a conventional example.

FIG. 8 is a partial plan view of a hearth of a rotary hearth furnace according to a conventional example.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] A refractory structure of a rotary hearth furnace according to an embodiment of the present invention will be described below with reference to Figs. FIG. 1 is a partial vertical sectional view showing a hearth structure of a rotary hearth furnace according to an embodiment of the present invention, FIG. 2 is a partial detailed sectional view showing an enlarged portion A of FIG. 1, and FIG. 4 is a partial plan view of a part of the rotary hearth 10 in a plan view, and FIG. 4 is an enlarged view of the arrow BB in FIG. It is a detailed sectional view.

As shown in FIG. 1, a rotary hearth furnace 1 according to an embodiment of the present invention includes an inner peripheral wall 2 and an outer peripheral wall 3, and a rotary furnace provided between the inner peripheral wall 2 and the outer peripheral wall 3. With floor 10. This rotary hearth 10 has a refractory structure. Specifically, the hearth frame 4 that forms the framework of the rotary hearth 10, the plurality of heat-insulating castables 5, the plurality of heat-insulating bricks 6a, and the plurality of refractory bricks 6b provided on the hearth frame 4 in order from the bottom. , And a plurality of irregular-shaped refractories 7 and corner metal refractories 8, 9 made of precast blocks.

[0020] The hearth frame 4 is disposed so as to be rotatable around a vertical axis in the furnace. In this embodiment, the corner refractories 8 and 9 are made of a precast refractory. The corner refractories 8 and 9 are arranged on the hearth frame 4 at positions on the inner peripheral wall 2 side and on the outer peripheral wall 3 side. Each is arranged. In addition, the above-mentioned amorphous refractory 7 is disposed in a region sandwiched between the corner refractories 8 and 9.

[0021] The amorphous refractory 7 constitutes a surface portion of the rotary hearth 10, and is constituted by a castable refractory. A plurality of these irregular-shaped refractories 7 are arranged in both the radial direction and the circumferential direction of the rotation, and the first expansion block 11 and the second expansion block 12 are interposed between the irregular refractories 7. Is placed. These blocks 7, 11 and 12 may be precast fireproof blocks.

First, in the radial direction, the amorphous refractory 7 is arranged in two rows of the radially inner side and the radially outer side, and the amorphous refractory adjacent to each other in the radial direction. A third expansion allowance (lower radial expansion allowance) 13 as shown in FIG. 2 is secured between them. In this embodiment, the third expansion allowance 13 is constituted by a groove-shaped lower gap 13a in the circumferential direction of the rotation formed between the irregular refractories, and the irregular refractory. It is located near the center of the hearth in the radial direction of the lower layer of object 7. The width dimension S3 of the groove-like lower gap 13a is, for example, 12 mm.

[0023] Of each of the irregular refractories 7, a portion above the lower gap 13a and adjacent to the lower gap 13a from the radial direction is opened upward as shown in FIG. The first recess 17a is formed, and the first expansion block 11 is detachably mounted in the first recess 17a. In this embodiment, the first expansion block 11 is in the circumferential direction. The first inflating allowance block 11 is divided into a plurality of first recesses that straddle the lower gap 13a and are adjacent to the first inflating allowance block 11 in the radial direction and outside force respectively. The groove-like upper gap 11a and the lower gap l ib are arranged between the inner peripheral surface of 17a. Each of the groove-like gaps 11a and l ib has, for example, a shape with a width dimension S1 of 6 mm and a depth dimension hi of 65 mm. Further, the width dimension of the first expansion allowance block 11, in other words, the radial distance L1 between the upper gaps 11a and ib is, for example, 150 mm. One groove-like lower gap 13a forming the third expansion margin 13 is directly below the first expansion expansion block 11, that is, below the amorphous refractory 7 in the range of the distance L1 in the radial direction. It is preferably arranged so as to fit. Further, one of the groove-like gaps 11a and l ib may be omitted, and thermal expansion may be absorbed only by the other.

[0024] This structure makes it possible to prevent intrusion of powder foreign matter into the groove-like lower gap 13a constituting the third expansion margin 13, and facilitates inspection of the lower gap 13a as will be described later. To This inspection is performed by removing the first expansion allowance block 11 as necessary.

[0025] At this time, the groove-like upper gaps 11a, l ib forming the first expansion allowance block 11 and the groove-like lower gap 13a forming the third expansion allowance 13 do not overlap in the vertical direction. It is important to place it at the position. If the lower gaps 11a, l ib and the upper gap 13a overlap in the vertical direction, the groove depth at that position becomes deeper in the circumferential direction and the fireproof function is reduced. When a foreign powder enters, there is a limit to the removal of this foreign powder.

[0026] The refractory structure having the first expansion allowance block 11 and the third expansion allowance 13 as described above absorbs the thermal expansion in the radial direction of the hearth refractory. Further, in this structure, the powder foreign matter enters the groove-like upper gaps 1 la and ib formed on the inside and outside in the radial direction of the first expansion allowance block 11, so that the refractory is thermally expanded in the radial direction. Even if the function to absorb is hindered, it can be repaired by removing only the first expansion block 11.

[0027] It is preferable that the groove depth hi of each of the groove-like gaps 11a and l ib is set within a range of 10 to 500 mm. Further, it is set within a range of 30 to LOOmm. More preferred. The groove When the groove depth hi of the groove-like gaps 11a and l ib is less than 10 mm, the groove-like gaps 11a and l ib cannot exert the function as an allowance for expansion. When the groove depth h1 of the groove-like gaps 11a, l ib is less than 30 mm, it is difficult for these groove-like gaps 11a, l ib to expand and perform their functions. On the contrary, when the groove depth hi of the groove-like gap exceeds 100 mm, it is difficult to suck and remove the powder foreign matter that has entered the groove-like gaps 11a and ib. Suction removal is almost impossible.

[0028] The distance L1 between the two groove-like gaps 11a and l ib forming the first expansion allowance block 11 may be determined mainly from the viewpoint of facilitating inspection and repair. In general, the distance L1 is preferably set within a range of 10 to 1000 mm, and more preferably set within a range of 100 to 200 mm. If the distance L1 between the two groove-like gaps 11a and l ib is less than 100 mm, the groove-like gap is too close and easily damaged and difficult to inspect. If it is less than 10 mm, almost no inspection is possible. is there. In addition, when the distance L1 exceeds 200 mm, in particular when it exceeds 1000 mm, there is a region 7a of the hearth refractory structure to be repaired when powder foreign matter enters and adheres to the groove-like gaps 11a and ib. It becomes wide.

[0029] The groove width SI of the two groove-like gaps 11a, l ib forming the first expansion allowance block 11 is the thermal properties of the refractory used, the operating temperature, and the first expansion allowance block 11 It may be determined based on the number of installations. In general, it is preferably set within a range of 3 to 25 mm. This is because if the groove width SI of the groove-like gaps 11a and l ib is less than 3 mm, the function as an expansion margin cannot be exerted, and if it exceeds 25 mm, the fireproof function on the hearth structure is hindered.

The groove width S3 of the groove-like gap 13a that forms the third expansion margin 13 may be determined based on the thermal properties of the refractory used, the operating temperature, and the number of the expansion margins 13 installed. In general, it is preferably set within a range of 3 to 25 mm. If the groove width S3 of the groove-like gap 13a is less than 3 mm, the function as an expansion margin cannot be exhibited as in the case of the groove-like gaps 11a and l ib forming the first expansion allowance block 11. If it exceeds 25mm, the fireproof function on the hearth structure will be hindered.

[0031] The position of the first expansion allowance block 11 is not limited to the vicinity of the center of the hearth. If this position can absorb the thermal expansion of the refractory in the radial direction, the center of the hearth For example, a position between the corner refractories 8 and 9 and the adjacent amorphous refractory 7 may be used.

[0032] The number of columns of the first expansion allowance block 11 is not limited to one. If the number of the first expansion allowance block 11 is singular, if the thermal expansion in the radial direction of the refractory cannot be sufficiently absorbed, the first expansion block 11 is provided at a plurality of locations in the radial direction, for example, at a plurality of locations spaced by 1500 mm. 1 An expansion allowance block 11 may be provided. Such distributed arrangement of the expansion allowance blocks across multiple rows according to the degree of thermal expansion in the radial direction of the hearth refractory enables more effective absorption of the thermal expansion in the radial direction of the refractory. .

Next, the arrangement in the circumferential direction of the irregular refractory 7 will be described. A plurality of these irregular-shaped refractories 7 are arranged in the circumferential direction as shown in FIG. 3, and a second refractory 7 as shown in FIG. 4 is interposed between the irregular-shaped refractories adjacent to each other in the circumferential direction. Expansion margin (diameter downward expansion margin) 14 is secured. In this embodiment, the second expansion margin 14 is constituted by a lower gap 14a formed between the irregular refractories. The lower gap 14a has a groove shape extending in the radial direction of the rotation and has a groove width S2.

[0034] Of each of the irregular refractories, a portion above the lower gap 14a and adjacent to the lower gap 14a from the circumferential direction is opened upward as shown in FIG. A second recess 17b is formed, and the second expansion allowance block 12 is detachably mounted on the second recess 17b. In this embodiment, the second expansion allowance block 12 extends linearly in the radial direction within the area between the corner refractories 8, 9, straddling the lower gap 14a, and A groove-shaped upper gap 12a and an upper gap 12b are secured between the second expanding and squeezing block 12 and the inner peripheral surface of the second recess 17b adjacent from the inner side and the outer side in the circumferential direction. Placed.

[0035] The groove-like gaps 12a and 12b are located at a distance L2 from each other in the radial direction. Like the groove-like upper gaps 11a, ib on both sides of the first expansion allowance block 11, the width S2 of each of the groove-like upper gaps 12a, 12b is, for example, 6 mm, the depth h2 is, for example, 65 mm, and the distance L2 is an example For example, it is set to 150mm. The groove 12a for forming the fourth expansion margin 14 is formed on both sides of the second expansion margin block 12 at a position where the second expansion margin block 12 is substantially equally divided at a pitch p in the circumferential direction. Distance between two groove-like gaps 12a, 12b L2 (for example If it is within the range of 150 mm), it is arranged so as to fit in the lower layer of the irregular refractory 7. Further, one of the groove-like gaps 12a and 12b may be omitted, and thermal expansion may be absorbed only by the other.

[0036] This structure makes it possible to prevent intrusion of powder foreign matter into the groove-like lower gap 14a constituting the fourth expansion margin 14, and facilitates inspection of the lower gap 14a as will be described later. To This inspection can be performed by removing the second expansion allowance block 12 as necessary.

[0037] At this time, circumferential positions where the groove-like upper gaps 12a, 12b constituting the second expansion allowance block 12 and the groove-like lower gap 14a constituting the fourth inflation allowance 14 do not overlap in the vertical direction. It is essential that the first expansion expansion block 11 and the groove-like gap 13a constituting each third expansion expansion block 13 are the same as described above. If the groove-like upper gaps 12a, 12b and the groove-like lower gap 14a overlap in the vertical direction, the groove depth at that position becomes deeper in the radial direction, and the fireproof function is reduced. This is because there is a limit to the removal of powdered foreign matter when it enters the gap.

[0038] The groove depth h2 of the two groove-like gaps 12a, 12b on both sides of the second expansion allowance block 12 is within the range of 10 to 500 mm for the same reason as the first expansion allowance block 11. Furthermore, it is preferable to be set in the range of 30 to: LOOmm.

[0039] Further, the groove width S2 and the distance L2 of the groove-like gaps 12a and 12b forming the second expansion allowance block 12 have the same viewpoint force as the first expansion allowance block 11 described above. It only has to be done. Specifically, the groove width S2 is preferably set within a range of 3 to 25 mm, and the interval L2 within a range of 10 to: LOOOmm. Further, the interval L2 is set within a range of 100 to 200 mm. More preferred ,.

[0040] The number of the second expansion allowance block 12 is appropriately determined depending on the size of the rotary hearth furnace 1, the thermal properties of the refractory used, and the operating temperature. In general, it is preferable that a plurality of second expansion allowance blocks 12 be arranged at a pitch p of 100 to 1 OOOOmm in the circumferential direction, preferably at a pitch p of 500 to 4000 mm. If the second expansion allowance block 12 is singular, for example, it becomes difficult to absorb the thermal expansion of the hearth refractory at the position opposite to the second expansion allowance block 12 (rotation symmetry side). It is. [0041] Further, the groove width S4 of the groove-like gap 14a forming the fourth expansion margin 14 is also determined based on the thermal properties of the refractory used, the operating temperature, and the number of installation formulas of the fourth expansion margin 14. However, for the same reason as the third expansion allowance 13, it is usually preferable to set within the range of 3 to 25 mm.

[0042] Each of the expansion margins may be constituted by the gaps as described above, and is sandwiched between the adjacent amorphous refractories 7 of the amorphous refractories 7 and has fire resistance. You may include a lower refractory stretchable material that can stretch in the adjacent direction! As the lower refractory stretch material, for example, an inorganic fiber refractory is suitable. An example of repair procedure for a rotary hearth that uses such a lower refractory expansion / contraction material is shown in Fig. 2, which is a perspective view of a part of the surface layer of the hearth in a cross section. This will be described in detail below with reference to FIG.

[0043] Step 1: The irregular refractory 7 in the area to be repaired in the hearth 10 is removed, thereby exposing the upper surface of the refractory brick 6b in the area. Oil paper 15 is spread on the exposed upper surface of the refractory brick 6b. This is to prevent a castable refractory for forming a split frame, which is poured onto the upper surface of the refractory brick 6b as described later, from entering the gaps between the refractory brick 6b and the corner refractory 8 and 9. is there.

Step 2: A fiber board 113 and a plurality of fiber boards 114 are arranged on the oil paper 15.

The fiber board 113 constitutes the third expansion margin, has a width S3, extends in the circumferential direction, and is disposed at a corresponding radial position. Each of the fiber boards 114 constitutes a fourth expansion margin, has a width S4, extends in the radial direction, and is disposed at a corresponding circumferential position.

Step 3: A plurality of molds 16 a are disposed on the fiber board 113 and a plurality of molds 16 b are disposed on the fiber board 114. As will be described later, the mold 16a includes a fiber plate 11 la constituting the first expansion allowance block 11 and the first expansion allowances on both sides thereof when the irregular refractory 7 is formed by pouring a castable refractory. , 11 lb to secure the space for placement. Each mold 16a is made of, for example, styrene foam, and has a width corresponding to the sum of the distance L 1 between the fiber boards 111a and 111b and the width S 1 (= L 1 +2 XS 1), and the fiber board. 111a, 111b has a height higher than hi, has an arc shape that curves along the circumference, and is sequentially arranged on the fiber board 13 while being connected to each other in the circumferential direction. Is done. The mold 16b is for securing a space for arranging the second expansion allowance block 12 and the fiber boards 112a and 112b constituting the second expansion allowances on both sides thereof. Each mold 16b also has, for example, a polystyrene foam force, and has a width corresponding to the sum of the distance L2 between the fiber boards 112a and 112b and its width S2 (= L2 + 2 X S2) and the height of the fiber boards 112a and 112b. It has a height of h2 or more, extends linearly in the radial direction, and is disposed on the fiber board 14 at positions on both sides of the mold 16a in the radial direction.

Step S4: The amorphous refractory 7 having a predetermined thickness is formed in the hearth space on the oil paper 15 in a region other than the molds 16a and 16b and the fiber boards 113 and 114. This molding is performed, for example, by pouring a castable refractory into the region, firing and drying the castable refractory. Thereafter, the molds 16a and 16b are removed. By this removal, a first recess 17a which is a groove space extending in the circumferential direction and a second recess 17b which is a groove space extending in the radial direction are obtained. The fiber plates 111a and 111b are arranged in the circumferential direction along both side surfaces of the first recess 17a, and the fiber plates 112a and 112b are arranged in the radial direction along both side surfaces of the second recess 17b. The

Step S5: A first inflatable spar block 11 and a second inflatable spar block 12 are formed by pouring castable refractory into the recesses 17a and 17b to a predetermined thickness. Finally, the entire construction area is heated and dried to complete the construction.

[0048] Examples of the fibers constituting each fiber board include ceramic fibers such as alumina fibers and inorganic fibers such as carbon fibers. In addition to such fiberboard, blankets and felts can also be used.

[0049] The fact that each expansion allowance is constituted by the lower refractory stretchable material as described above enhances work efficiency. This is because the amount of powder generated by misalignment or deterioration of the hearth refractory enters between the irregular refractories 7 is reduced, and the repair interval of the refractory structure is extended accordingly.

[0050] Next, a coping method and effect in the case where a powder foreign matter enters the gap constituting the expansion margin of the rotary hearth according to the present invention will be specifically described below with reference to FIG.

In the structure shown in FIG. 3, as described above, in the surface layer portion of the irregular refractory 7, a plurality of first expansion allowance blocks 11 are arranged in the circumferential direction in one row in the radial direction, These first expansion allowance blocks 11 have two groove-like gaps 11a and l ib extending in the circumferential direction. It is sandwiched between.

[0052] In this structure, when, for example, regular inspection confirms that a foreign powder has entered the groove-like upper gaps 11a, ib on both sides of the first expansion allowance block 11 in the shaded area, The powder foreign matter in the groove-like upper gap 11a, l ib is removed by suction with a vacuum cleaner or the like. Since the groove depth hi of the groove-like gaps 11a and l ib is limited, most of the powdered foreign substances therein can be removed by suction.

[0053] When a long period of time has passed since a foreign substance such as powder has intruded while the force is applied, the foreign substance enters the surface of the irregular refractory 7 or the first expansion allowance block 11 within the groove-like upper gap. Since it adheres, it is difficult to remove the foreign matter by suction. When this situation is reached, the first expansion allowance block 11 in the shaded area is destroyed and removed. The removal of the first expansion allowance block 11 facilitates the removal of the powder foreign matter that has entered the groove-like upper gaps 11a and ib. Therefore, in this case, only the first expansion allowance block 11 in the shaded area needs to be repaired.

[0054] If the hearth refractory is thermally expanded in the radial direction and the corner refractories 8 and 9 are pressed while the powder foreign matter has entered the groove gaps 11a and l ib in the shaded area, the corner refractories 8 and 9 are pressed. Even if the one refractory 8 or 9 is damaged, the parts that are damaged inside the corner refractories 8 and 9 are the first expansion allowance block 11 in the shaded area and the shaded area. Only the irregular refractories 7a and 7b sandwiching the first expansion block 11 are provided. Therefore, it is only necessary to remove and repair only these irregular shaped refractories 7a and 7b and replace the damaged corner refractories. This allows for savings in repair materials and a significant reduction in construction effort.

[0055] In FIG. 3, the procedure is the same as that described above even when it is confirmed that powder foreign matter has entered the groove-like gaps 12a and 12b on both sides of the second expansion allowance block 12 in the shaded area. . That is, for the same reason as described above, the powder foreign matter in the groove-like gaps 12a and 12b in the shaded area can be removed by suction. The second expansion allowance block 12 may be removed. After the removal, it is sufficient to repair only the expansion allowance block 12 in the shaded area after removing the powder foreign matter that has entered the groove-like gaps 12a and 12b. [0056] Also, even if the hearth refractory expands in the circumferential direction with the powder foreign matter remaining and pushes the hearth refractory to cause damage, the expansion allowance block 12 in the hatched area, Only the irregular shaped refractories 7c and 7d adjacent to this need only be removed and repaired, so that repair materials can be saved and construction labor can be greatly reduced.

As described above, in the rotary hearth according to the present invention, a plurality of amorphous refractories and a plurality of expansion allowances are provided on the hearth frame between the inner corner refractory and the outer corner refractory. A block is provided. A plurality of the irregular refractories are arranged in at least one of the radial direction and the circumferential direction of rotation of the hearth frame, and among the irregular refractories, the irregular refractories adjacent to each other are arranged. The irregular-shaped refractory is arranged so that a lower expansion margin is provided between the upper and lower expansion margins of each irregular refractory and with respect to the lower expansion margin. A concave portion opened upward is formed in the adjacent portion. The expansion allowance block is formed in a recess of adjacent irregular refractories among the irregular refractories, and the expansion allowance block straddles the lower expansion allowance and at least one of the expansion allowance blocks. The refractory is placed so as to be attachable and detachable so as to ensure an upward expansion margin with the inner peripheral surface of the concave portion of the regular refractory.

[0058] In this rotary hearth, if it is confirmed that any foreign powder has entered the upper expansion margin, it is sufficient to repair only the expansion margin block corresponding to the upper expansion margin. This makes it possible to save repair materials, save repair time and shorten the construction period. In addition, since the lower expansion margin between the irregular refractories is located immediately below the expansion margin block, entry of foreign matter into the lower expansion margin can be prevented. Therefore, the thermal expansion of the lower layer of the amorphous refractory is not hindered.

[0059] Specifically, a plurality of the amorphous refractories are arranged at least in the radial direction of the rotation, and the radial refractories are adjacent to each other in the radial direction among the irregular refractories. The irregular refractory is arranged so that a lower expansion margin is provided, and the concave portion is arranged in the radial direction with respect to the radial lower expansion margin of each irregular refractory. A first recess formed in an adjacent portion, wherein the expansion allowance block is disposed in the first recess of the amorphous refractory adjacent to each other in the radial direction in the amorphous refractory. The first recess of at least one amorphous refractory that straddles the lower expansion margin In the case of including a first expansion allowance block that is detachably mounted so as to secure the radially upward expansion allowance between the inner peripheral surface of the non-circular refractory in the radial direction. Inhibition of expansion is prevented.

[0060] Further, a plurality of the irregular refractories are arranged at least in the circumferential direction of the rotation, and among the irregular refractories, between the irregular refractories adjacent to each other in the circumferential direction, The irregular refractory is arranged so that a side expansion margin is provided, and the concave portion is formed in a portion adjacent to the circumferential direction with respect to the lower expansion margin in the circumferential direction as the concave portion. The expansion allowance block extends across the lower expansion allowance in the circumferential direction in the second recesses of the irregular refractories adjacent to each other in the circumferential direction among the irregular refractories. And a plurality of second expansion allowance blocks each detachably mounted so as to secure an upper expansion allowance in the circumferential direction between the inner peripheral surface of the second recess of the at least one irregular refractory. In the case of including The thermal expansion of monolithic refractories is it can be prevented that the inhibition of.

[0061] Further, a plurality of the irregular refractories are arranged in the radial direction in addition to the circumferential direction of the rotation, and among the irregular refractories, between the irregular refractories adjacent to each other in the radial direction. The irregular refractory is disposed so that a lower expansion margin in the radial direction is provided in the radial direction, and the lower expansion of the irregular refractory in the radial direction is included as the concave portion in addition to the second concave portion. A first recessed portion formed in a portion adjacent to the radial direction with respect to the margin, wherein the expansion squeeze block is divided in the circumferential direction of the irregular refractory in addition to the second expansion squeeze block A plurality of first expansion squeeze blocks divided in the circumferential direction at the same location, and these first expansion squeeze blocks are non-adjacent ones of the irregular refractories adjacent to each other in the radial direction. In the first recess of the regular refractory, If it is detachably mounted so as to secure an upper expansion margin in the radial direction across the expansion margin and between the inner peripheral surface of the concave portion of at least one irregular refractory, the radial direction and In both circumferential directions, the thermal expansion of the amorphous refractory is prevented from being inhibited.

[0062] Further, the lower expansion margin includes a lower gap formed between adjacent amorphous refractories among the irregular refractories, and has a depth of 30 mm or more and 1 OO mm or less. If it has a size, even if foreign matter enters the lower gap, the foreign matter is absorbed. It is relatively easy to pull and remove, and even if the suction removal becomes impossible, the size of the expansion allowance block to be removed can be minimized.

[0063] Further, when the upper expansion margin includes an upper gap, and the upper gap has a depth dimension of 30 mm or more and 100 mm or less, even if a foreign object enters the upper gap, the removal is removed. Can be easily performed.

[0064] In addition, the lower expansion margin is sandwiched between adjacent amorphous refractories among the irregular refractories, and has a fire resistance and can expand and contract in the adjacent direction. A material including an elastic material or the upper expansion margin is sandwiched between the expansion expansion block and an inner peripheral surface of at least one concave portion adjacent to the expansion margin block, and has fire resistance and expands and contracts in the adjacent direction. In the case of including a possible upper refractory expansion / contraction material, it is possible to suppress powder foreign matter entering the groove-like gap while securing the expansion margin, thereby extending the interval of suction removal and repair work of intruding foreign matter. be able to.

Claims

The scope of the claims

[1] A rotary hearth provided in a rotary hearth furnace,

A hearth frame rotatably installed in the furnace of the rotary hearth furnace;

An inner peripheral corner refractory and an outer peripheral corner refractory respectively disposed on the inner peripheral portion and the outer peripheral portion of the hearth frame;

A plurality of inflatable refractories and a plurality of expansion allowance blocks made of a refractory provided on the hearth frame between the inner peripheral corner refractories and the outer peripheral corner refractories,

A plurality of the irregular refractories are arranged in at least one of the radial direction and the circumferential direction of the rotation of the hearth frame, and the irregular refractories adjacent to each other among these irregular refractories. The irregular refractory is arranged so that a lower expansion margin is provided between the refractories, and the lower expansion margin of each irregular refractory is higher than the lower expansion margin. A recess opened upward is formed in a portion adjacent to the expansion refractory block, and the expansion squeeze block is provided in the recess of the amorphous refractory adjacent to each other among the irregular refractory. It is detachably mounted so that an upper expansion margin is secured between the expansion expansion block straddling the lower expansion expansion margin and the inner peripheral surface of the concave portion of at least one irregular refractory.

[2] In the rotary hearth according to claim 1,

A plurality of the irregular refractories are arranged at least in the radial direction of the rotation, and a lower expansion margin is provided between the irregular refractories adjacent to each other in the radial direction among the irregular refractories. And the concave portion is formed in a portion adjacent to the radial direction with respect to a lower expansion margin in the radial direction of each of the irregular refractory materials. Including a first recess,

The expansion allowance block spans at least one of the irregularly shaped refractories, straddling the lower expansion margin in the radial direction in the first recesses of the irregularly shaped refractories adjacent to each other in the radial direction. A first expansion allowance block that is detachably mounted so as to secure the radially upward expansion allowance between the inner peripheral surface of the first recess of the object.

[3] In the rotary hearth according to claim 1, A plurality of the irregular refractories are arranged at least in the circumferential direction of the rotation, and a lower expansion margin is provided between the irregular refractories adjacent to each other in the circumferential direction among the irregular refractories. In addition, the irregular refractory is disposed, and the recess is formed in a portion adjacent to the circumferential direction of the irregular refractory with respect to a lower expansion margin in the circumferential direction. Including a second recess,

The expansion margin block spans the lower expansion margin in the circumferential direction in the second recesses of the irregular refractories adjacent to each other in the circumferential direction among the irregular refractories and at least one irregular refractory. A plurality of second expansion allowance blocks that are detachably mounted so as to ensure the upper expansion allowance in the circumferential direction between the inner peripheral surface of the second recess of the object.

[4] In the rotary hearth according to claim 3,

A plurality of the irregular refractories are arranged in the radial direction in addition to the circumferential direction of the rotation, and among the irregular refractories, the irregular refractories adjacent to each other in the radial direction are arranged in the radial direction. The irregular refractory is arranged so that a lower expansion margin is provided, and, in addition to the second recess, as the concave portion, the radial lower expansion margin of each irregular refractory in the radial direction is provided. A first recess formed in a portion adjacent to the radial direction with respect to the expansion squeeze block, in addition to the second expansion squeeze block, in addition to the circumferential division of the irregular refractory A plurality of first expansion and squeeze blocks divided in the circumferential direction at these locations, and these first expansion and squeeze blocks are the first of the irregular refractories that are adjacent to each other in the radial direction. 1 Place the lower expansion margin in the radial direction in the recess. Wherein at white upper expansion in the radius direction direction it is removably mounted so as to be secured between the inner peripheral surface of the recess of Gikatsu at least one of the monolithic refractories.

[5] In the rotary hearth according to any one of claims 1 to 4,

The lower expansion margin includes a lower gap formed between the amorphous refractories adjacent to each other among the irregular refractories.

[6] In the rotary hearth according to claim 5,

The lower gap has a depth dimension of 30 mm or more and 100 mm or less.

[7] In the rotary hearth according to any one of claims 1 to 6, The lower expansion margin includes a lower refractory material that is sandwiched between adjacent amorphous refractories among the irregular refractories, has fire resistance, and can expand and contract in the adjacent direction. A rotary hearth characterized by that.

[8] In the rotary hearth according to claim 7,

The rotary hearth characterized in that the lower refractory stretchable material is an inorganic fiber refractory.

[9] In the rotary hearth according to any one of claims 1 to 8,

The rotary hearth is characterized in that the upper expansion margin includes an upper gap formed between the expansion expansion block and an inner peripheral surface of at least one concave portion adjacent thereto.

[10] In the rotary hearth according to claim 9,

The rotary hearth is characterized in that the upper gap has a depth dimension of 30 mm or more and 100 mm or less.

[11] In the rotary hearth according to claim 9 or 10,

The rotary hearth is characterized in that an upper gap between both sides of the upper expansion allowance block is 100 mm or more and 200 mm or less.

[12] In the rotary hearth according to any one of claims 1 to 11,

The upper inflatable margin is sandwiched between the inflatable margin block and an inner peripheral surface of at least one concave portion adjacent thereto, and has an upper fireproof stretchable material that has fire resistance and can be expanded and contracted in the adjacent direction. A rotary hearth characterized by including.

[13] In the rotary hearth according to claim 12,

The rotary hearth characterized in that the upper refractory stretchable material is an inorganic fiber refractory.