JP2001012859A - Lining refractory for rotary kiln - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lining refractory for a rotary kiln, which realizes a stable cement coating at an earlier stage and can be readily set. SOLUTION: A rotary kiln has a lining structure in which the inner surface of a furnace of a lining refractory is provided with recess and protrusion. The lining refractory for the rotary kiln comprises refractory brick 15a wherein a portion of the inside of the furnace is formed with a recessed and protruded portions including a recess 13a and a protrusion 12a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refractory lining for a rotary kiln, and more particularly to a refractory lining for a cement rotary kiln.

[0002]

2. Description of the Related Art A cement rotary kiln is a facility for producing a cement clinker through a sintering reaction by charging fine powder materials such as limestone, clay and silica stone into a rotary kiln rotating at a high temperature. Its inner surface is lined with refractory.

[0003] The refractory lining in the sintering zone for sintering the fine powder raw material is exposed to a high temperature of about 1650 ° C, receives thermal stress, and undergoes a chemical reaction with the raw material and the like, resulting in deterioration of the composition. In addition, due to mechanical stress or the like due to rotation of the kiln, various spalling or erosion effects cause a decrease in durability and a short life. For this reason, in the firing zone of the rotary kiln, a highly durable "magnesia-chromium refractory" having improved spalling resistance and corrosion resistance is used as a refractory lining. Recently, a "chromium-free spinel refractory" having improved durability has been used as an environmental measure.

On the other hand, in order to further improve the durability of the above-mentioned refractories, during the production process of cement clinker,
Cement coating, in which the surface of the refractory lining is coated with cement clinker, has become indispensable. Therefore, it has been conventionally proposed to improve the composition of the refractory to promote cement coating, for example, the following (1) to (4)
A refractory lining having the following composition has been proposed.

(1) Japanese Unexamined Patent Publication No. Hei 5-238809 discloses that “magnesia-chromium bricks have a Fe ₂ O ₃ content of 3.5 to 10.0.
Wt%, CaO content: 1-3 wt%, Cr ₂ O ₃ content: 6-15
% By weight "is described. And
As a means to give the brick flexibility and to improve the coating adhesion, "2CaO.Fe ₂ O ₃ "
Is generated, and “4C” is generated near the interface between the brick and clinker.
there is described _{aO · Al 2 O 3 · Fe} 2 O 3 and magnesia-chromium-based brick were generated 2CaO · SiO ₂ ". However, this brick, flexibility, although coating adhesion increases (however, Although the adhesion of the coating is not sufficiently improved, there is a problem in that the strength and durability of the brick itself are considerably reduced and the life is not prolonged.

(2) Japanese Patent Application Laid-Open No. Hei 7-237960 discloses that “magnesia having an appropriate MgO content is mixed with 1 to 6% by weight of chromium oxide.
Magnesia-chromium refractory further containing 0.2 to 10% by weight of zirconia ", and the refractory has improved coating adhesion, corrosion resistance and spalling resistance. It is described as being suitable for use as a cement rotary kiln refractory because of its improved service life. However, in this refractory, although the corrosion resistance and spalling resistance of the refractory are improved, it is not possible to expect further improvement in the adhesion of the coating.

(3) JP-A-6-160014 discloses that "Rare earth oxides (Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ ) are contained in a spinel refractory and MgO-Al ₂ O ₃ The grain size of the spinel material
Spinel refractories containing rare earth oxides with a thickness of 0 μm or more ”
It is described that the refractory is suitable as a refractory for lining a cement kiln because the refractory increases the coating adhesion. However, this refractory is a refractory in the category of spinel quality,
Currently used “magnesia-chrome bricks”
In comparison with, the coating adhesion is considerably lower, and because it is a special formulation (additive addition), the cost is high,
There is a problem that.

(4) Japanese Patent Application Laid-Open No. 7-267720 discloses "a basic brick in which 1 to 5% by weight of alumina cement having a refractory degree of SK33 or more is added to a refractory material mainly composed of magnesia-magnesia spinel". It is described that by adding alumina cement in this way, a basic brick having excellent coating adhesion and hot strength can be obtained. However, this basic brick is intended to improve the coating adhesion, but the coating adhesion itself is not sufficient.

As described above, in the magnesia-chromium refractory conventionally proposed (see the above-mentioned prior arts (1) and (2)), the corrosion resistance and the spalling resistance are improved. However, the coating adhesion is not sufficiently improved. In addition, recently, there has been a problem that spinel refractories (see the above-mentioned prior arts (3) and (4)), whose use amount is increasing, have insufficient cohesive adhesion.

Therefore, in order to solve the above-mentioned problems and further promote the adhesiveness of the coating, the following “liner kiln lining structure” as described in the following (5) to (7) has been proposed.

(5) Japanese Patent Application Laid-Open No. 5-248767 discloses that "a boundary portion of a refractory material lined with a firing zone and a coaching detachable zone in a lining of a rotary kiln, a magcro brick and a spinel brick are rotary kilns. Of the rotary kiln having a “zebra structure” laminated in a striped shape in the axial direction ”.

(6) Japanese Patent Application Laid-Open No. 8-313159 discloses that "a spalling-resistant spinel-based refractory and a coating-adhering spinel-based refractory are alternately laminated in a rotary kiln firing zone. And a rotary kiln firing zone lining structure in which the inner surface of the rotary kiln furnace is made “irregular”.

(7) Japanese Utility Model Application Laid-Open No. 51-48153 discloses that “a part of each surface or at least two surfaces of the refractory lining facing the inside of the furnace and at least two of the four surfaces adjacent to the surface are used. A refractory lining for a cement rotary kiln in which the entire surface is covered with a metal mainly composed of iron is described.

[0014]

In the prior arts (1) to (4), the composition of the refractory is improved. In the prior arts (5) to (7), the refractory is used. Are all intended to promote cement coating, but each has advantages and disadvantages as described below.

In the prior arts (1) to (4), the formation of cement coating is good to some extent, but hot strength and corrosion resistance are sacrificed, or conversely, hot strength and corrosion resistance are improved. However, the cement coating was not sufficiently formed.

In the prior art (5) (see Japanese Patent Application Laid-Open No. Hei 5-248767), a "zebra structure" is used in which a magcro brick and a spinel brick are stuck together in the axial direction of a rotary kiln in a striped manner. However, although the coating can be adhered to the porcelain brick portion, the coating has a disadvantage in that the coating is hardly adhered to the spinel brick, and even if it adheres to a certain extent, it is peeled off.

In the prior art (6) (see Japanese Patent Application Laid-Open No. 8-313159), since the main material is spinel, no improvement in coating adhesion can be expected. Since it is constructed using firebricks of different shapes (seri bricks having different heights) in order to form it in a “shape”, there is a problem that it is complicated.

In the prior art (7) (see Japanese Utility Model Laid-Open Publication No. 51-48153), the iron plate reacts with MgO in the basic refractory brick to chemically and materially melt the iron plate. It is intended to improve the durability by generating a strong reactant "MgO.Fe ₂ O ₃ layer", thereby promoting the coating of the cement material on the inner peripheral surface of the lining refractory brick, It is not enough effect.

The present inventors have conducted intensive studies in order to solve the above-mentioned drawbacks and problems, and as a result, have completed the present invention.
-Refractory of the composition in the prior art of (4) or a refractory of other composition is used alone or in combination of two or more, stable coaching is obtained, and the refractory lining for rotary kiln has high workability. Is to provide.

That is, an object of the present invention is to provide a cement rotary kiln that has high workability, regardless of the refractory of any material and composition, in the refractory of the lining of the cement rotary kiln (particularly, the refractory used in the firing zone). To provide a refractory lining for rotary kilns that can produce complete cement coating at an early stage during initial firing (at the first temperature rise after lining construction), resulting in the development of a long-life rotary kiln Is to do.

[0021]

According to the present invention, there is provided a rotary kiln lining refractory comprising: a rotary kiln lining refractory;
The refractory lining is made of a refractory brick, and formed a concave or convex portion on a part or the whole of the furnace inner surface side of the refractory brick (claim 1), characterized by (specifying the invention), Thus, the refractory lining for a rotary kiln as described above is provided.

[0022] The present invention also relates to the uneven portion, wherein a concave portion having a depth of 10 to 50 mm and a width of 10 to 50 mm is formed in a part of the refractory brick on the inner side of the furnace. -A concave portion having a depth of 0.5 to 5 mm is formed on the entire inner surface of the furnace of the refractory brick (Claim 3). It provides refractory lining.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below. Prior to that, the refractory lining for rotary kiln according to the present invention and its working effects will be described in detail in connection with the prior art.

Refractory lining of cement rotary kiln
The construction of (lining brick) is generally performed using a refractory of a highly durable material without making the inner peripheral surface uneven. Cement coating on the refractory lining (lining brick) starts to occur from the time the adhesion conditions are met due to the melting of the cement raw material, the surface condition of the lining brick, the mutual reactivity between the cement raw material and the lining brick, and the like. As one of the factors, roughness of the surface of the lining brick (unevenness generated by spalling, erosion, etc.) occupies a considerable weight. That is, starting from the rough surface of the brick, the adhesion of the cement raw material gradually grows, and a thick coating is formed.

Japanese Unexamined Patent Application Publication No. Hei 8-
Japanese Patent Publication No. 313159 describes a "lined structure having an uneven shape". That is, as described above, a "liner structure of a rotary kiln firing zone" is disclosed in which a concave portion on the inner surface of the furnace is made of a coating-adhering spinel refractory and a convex portion is made of a spalling-resistant spinel refractory. However, in this lining structure, since the main material is spinel, there is a problem that the coating adhesion is inferior to that of the magnesia-chromium refractory, and sufficient durability cannot be obtained.

Furthermore, in the lining structure described in the above-mentioned Japanese Patent Application Laid-Open No. 8-313159, as described below, as a means for forming the kiln inner surface in an “irregular shape”, fire bricks of different shapes (having a height of Since the construction is performed using different bricks, there is a problem that the construction is complicated.

Generally, as a means for applying a refractory lining of a rotary kiln, a machine construction method (such as a line chess construction method) in which a cell type brick is received in a frame on the inner peripheral surface of a shell and pressed and fixed by a beam. Has been done.

The "construction method for forming the inner surface of the kiln into an uneven shape" disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-313159 is performed by the mechanical construction method described above. This will be described with reference to FIG. FIG. 6 is a view for explaining a conventional method of constructing a refractory lining brick in a rotary kiln (construction method described in the above-mentioned Japanese Patent Application Laid-Open No. 8-313159), and [A] is a partial sectional view at the time of construction. [B] is a partially developed view of the inner surface of the furnace after construction.

In the construction method described in JP-A-8-313159, as shown in FIG. 6, a plurality of horizontal jelly refractory bricks having different heights (low seri bricks 2 and high seri bricks 3) are used. The concave portion 7 is formed by applying a base material (level adjusting material) 4 to a low-height horizontal jelly brick (low cellulite brick 2), setting the concave portion 7 and the convex portion 8 at the same level, and receiving the same by the frame 5. It must be pressed against the inner circumference of the beam with the beam 6. Therefore, there is a problem that work is very complicated and efficiency is low.

On the other hand, according to the present invention, as described above, a refractory brick is used as a refractory for lining a rotary kiln, and irregularities are formed on a part of or the entire inner surface of the furnace of the refractory brick. I do. That is, prior to the lining work, a refractory brick in which uneven portions are formed in advance is manufactured, and the refractory brick provided with the uneven portions is used for lining, thereby forming the uneven portion on the inner surface of the kiln.

Therefore, in the lining work, in the present invention,
Since the height (level) of the refractory brick to be used is constant, a level adjusting material such as a stock 4 (see FIG. 6 described above) as in the prior art (see JP-A-8-313159) is required. Without
There is an effect that the construction efficiency is extremely good.

Further, in the present invention, the formation of the uneven portion is performed before the lining work, and the uneven portion is formed on the surface of the brick (a part or the entire surface on the inner side of the furnace) in the process of manufacturing the refractory brick. It is. Then, as a forming means, in a preferred embodiment of the present invention, when providing an uneven portion at the time of molding the brick (when forming an uneven portion on a part of the furnace inner surface side), it is only necessary to change the mold. Therefore, the workability is good (see “First Embodiment of Concavo-convex Shape” described later),
In the case of sand blasting (when the uneven portion is formed on the entire inner surface of the furnace), since the uneven portion can be formed in the state of the substrate, there is an effect that the operation can be performed in a short time. Second Embodiment of Part Shape ").

In the present invention, the material (composition) of the refractory brick to be used is not particularly limited.
(1) to (4) can be arbitrarily applied to the refractory brick of the composition used in the prior art or other composition of the refractory brick, by combining these refractory bricks alone or two or more, Coating layers of any thickness can be formed.

(Means for Lining “Refractory Brick with Irregularities”) Next, FIG. 1 shows an embodiment of a method for lining a “firebrick with irregularities” on a rotary kiln according to the present invention. It will be described based on the following. FIG. 1 is a view for explaining this construction method. FIG. 1 [A] is a partial sectional view of a lining structure of a rotary kiln at the time of construction, and [B] is a part of the lining structure. It is a development view.

The lining of the brick 15 provided with the concave and convex portions on the rotary kiln is carried out by a conventional mechanical construction method. As shown in FIG. ) Is reversed, placed along the inner periphery of the shell 1 and pressed by a beam 6 via a frame 5 for construction. As a result, uneven portions (the concave portion 13 and the convex portion 12) are formed on the inner surface of the rotary kiln. As described above, in the present invention, as described above, it is necessary to apply the stock 4 (see FIG. 5 described above) as in the related art, by providing the uneven portion (the concave portion 13 and the convex portion 12) on the refractory brick itself. Not
Work efficiency is greatly improved. By forming the uneven portion on the inner surface of the rotary kiln, cement coating is first formed in the concave portion 13, and the cement coating is grown and formed up to the convex portion 12 starting from the concave portion 13.

(Embodiment of Concavo-convex Portion) Next, the embodiment of the “fire-resistant brick provided with concavo-convex portion” used in the present invention will be described with reference to FIGS. I do. 2 to 4 are perspective views of a refractory brick showing the first embodiment of the uneven portion shape (when the uneven portion is provided on a part of the inner surface of the furnace), and FIG. FIG. 1 is a perspective view of a refractory brick showing the embodiment (in the case where an uneven portion is provided on the entire inner surface of the furnace).

(First Embodiment of Concavo-convex Portion) The first embodiment of the shape of the "refractory brick provided with concavo-convex portions" (concavo-convex portion shape) used in the present invention is a method of forming a part on the inner surface side of the furnace. This is an example in which an uneven portion is provided. That is, as shown in FIG.
a, the refractory brick 15a provided with the convex portion 12a), the "refractory brick 15b provided with the concave and convex portion (the concave portion 13b, the convex portion 12b)" shown in FIG. 3, and [A] to [E] in FIG. This is an example in which the "refractory bricks 15c to 15g having the concave and convex portions (recesses 13c to 13g and the convex portions 12c to 12g)" are shown, and the concave and convex portions (recesses 13a to 13g) are formed on a part of the furnace inner surface.

The refractory bricks 15b to 15g shown in FIGS.
In this case, as shown in FIG. 2, a refractory brick having a structure covered with an iron plate 9 may be used, and such a refractory brick is also included in the present invention. (Note that 11 in FIGS.
Is a back surface (shell surface) of the refractory brick, and 14 is a side surface of the refractory brick. Also, “A” and “B” in FIGS.
"C" and "D" indicate the dimensions of the corresponding portions of the refractory bricks 15a and 15b. )

In the first embodiment, the depths and widths of the refractory bricks 15a to 15g shown in FIGS. It is desirable to do. This will be described with reference to the refractory bricks 15a and 15b shown in FIGS. 2 and 3. A part of the inner side of the furnace has a recess 13a having a depth (a) of 10 to 50 mm and a width (b) of 10 to 50 mm. 13b is preferably formed. Within this range, cement coating is easily formed. On the other hand, if it is out of this range, it is difficult to form cement coating, and if the depth (a) and the width (b) are more than 50 mm, the spalling resistance is undesirably deteriorated. In addition, the formation of the recesses 13a and 13b in this range can be achieved by forming the recesses 13a and 13b by using a molding mold at the time of brick molding.
It can be easily and efficiently manufactured in a normal manufacturing process.

(Second Embodiment of Concavo-convex Portion) As shown in FIG. 5, the second embodiment of the shape of the “fire-resistant brick provided with concavo-convex portion” used in the present invention is as shown in FIG. This is a refractory brick 15h in which an uneven portion 15 'is provided on the entire inner surface of the furnace.
(Note that 11 in FIG. 5 is the back surface (shell surface) of the refractory brick, and 14 is the side surface of the refractory brick.
"B", "C", and "D" indicate the dimensions of the relevant portion of the refractory brick 15h. )

In the second embodiment, the refractory brick 15h
As a means for forming the uneven portion 15 ′ on the entire surface on the inner side of the furnace, the refractory brick 15 h can be formed by sandblasting on the brick before or after firing, and particularly when the refractory brick 15 h is performed in the state of the base before firing, The formation of the concavo-convex portion 15 'can be extremely easily performed.

Also in the second embodiment, the refractory brick 15
It is desirable that the depth (a ′) of the recess formed on the entire surface of h be within a certain range, and it is preferable that the recess be 0.5 to 5 mm. By forming a concave portion within this range, cement coating is easily formed. depth
If (a ′) does not reach 0.5 mm, it is difficult to expect a sufficient effect, and if it exceeds 5 mm, it becomes difficult to form the concave portion by sandblasting as a means for forming the uneven portion 15 ′. Is not preferred.

As a means for forming the uneven portion on the refractory brick, as described above, a method of forming the uneven portion by using a molding mold at the time of forming the brick (first embodiment) A method of forming uneven portions by sand blasting (second embodiment) can be adopted, and then dried and fired to produce a refractory brick having uneven portions. In addition, in the second embodiment, a fire-resistant brick having an uneven portion can also be manufactured by a method of forming an uneven portion on the fired brick by sandblasting.

In the present invention, magnesia-chromium or spinel is mainly used as a material of the refractory brick. Among them, magnesia-chromium brick is particularly preferable, because the reason for the adhesion of the coating is that of magnesia-chrome. It is because it is excellent in the point. However, in the present invention, the material of the refractory brick is not particularly limited, and as described above, the refractory brick or a refractory brick of another material can be arbitrarily used. Alternatively, two or more kinds can be used in combination.

The refractory brick made of the above-mentioned material can be lined with a single material or in a composite structure such as a zebra structure. Further, the refractory brick provided with the concave and convex portions of the present invention may be appropriately combined with a normal refractory brick having no concave and convex portions, and these are all included in the present invention.

[0046]

Next, the present invention will be described in detail with reference to examples of the present invention. However, the present invention is not limited to the following examples 1 to 3.

(Example 1) 1) Molding of refractory brick: After being formed by a molding frame, dried and fired, a brick having a shape shown in FIG. 2 was produced. Overall size (A × B × C × D); 114 × 125 × 230 × 230
(mm) depth of the recess (a); 35 (mm) recess width (b); 25 (mm) 2) Material: spinel alone composition; MgO 79 wt%, Al ₂ O ₃ 17 wt% 3) L Type iron plate: thickness 2mm (l-type iron plate may be used)

(Example 2) 1) Molding of a refractory brick: After forming with a molding mold, drying and firing were performed to produce a brick having a shape shown in FIG. Overall size (A × B × C × D); 114 × 125 × 230 × 230
(mm) Depth of recess (a); 20 (mm) Width of recess (b); 20 (mm) 2) Material: magnesia-chromium Composition: 77% by weight of MgO 11% by weight of Cr ₂ O ₃

(Example 3) 1) Molding of refractory brick: After forming unevenness by sandblasting on an operation surface in a state of a base brick, it was fired to produce a brick having a shape shown in FIG. Overall size (A × B × C × D); 90 × 100 × 230 × 230
(mm) depth of the recess (a '); 0.5~5 (mm ) 2) Material: Magnesia chrome quality composition; MgO 77 wt% Cr ₂ O ₃ 11 wt%

[0050]

As described above in detail, the present invention uses a refractory brick as a refractory for lining a rotary kiln,
An uneven portion is formed on part or the entire surface of the refractory brick, and the unevenness is formed on the inner surface side of the rotary kiln by lining the refractory brick provided with the uneven portion. As described above, in the present invention, the roughening of the furnace inner surface that occurs during the operation of the rotary kiln is artificially made,
Coating adhesion is easily generated. And, in the present invention, since the height of the refractory brick to be used is constant when applying the refractory brick to the rotary kiln, no special jig is required for holding the brick, and the construction efficiency is extremely good. This produces the effect.
For this reason, it is advantageous also in terms of manufacturing and construction costs.

Further, in the present invention, in the process of manufacturing a refractory brick, an uneven portion is formed on the brick itself. As a forming means, when the uneven portion is provided at the time of molding the brick, a special work process is required. Can be easily formed by a normal process using a molding die, and in the case of sandblasting, since the uneven portion can be formed in a base state, it can be performed in a short time.

Further, in the present invention, the material (composition) of the refractory brick to be used is arbitrary, and the refractory brick can be of any thickness by combining two or more refractory bricks of a single material or different materials (composition). Can be formed.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view for explaining a method of lining a “refractory brick having an uneven portion” on a rotary kiln according to the present invention;
FIG. 1A is a partial cross-sectional view of a lining structure of a rotary kiln at the time of construction, and FIG. 1B is a partially developed view of the lining structure.

FIG. 2 is a perspective view of a “firebrick having an uneven portion” according to the present invention, which is an example of the first embodiment.

FIG. 3 is a perspective view of a refractory brick showing another example of the first embodiment, which is the “refractory brick having uneven portions” of the present invention.

FIG. 4 is a perspective view of a “fire-resistant brick having an uneven portion” according to the present invention, which is another example of the first embodiment.

FIG. 5 is a perspective view of a “firebrick having an uneven portion” according to the present invention, showing a second embodiment of the firebrick.

6A and 6B are views for explaining a conventional method for applying a refractory lining to a rotary kiln, in which [A] is a partial cross-sectional view at the time of construction, and [B] is a partial development view of a furnace inner surface after the construction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shell 2 Low seri brick 3 High seri brick 4 Rootstock (level adjustment material) 5 Frame 6 Beam 7 Concave part 8 Convex part 9 Iron plate 11 Back (shell surface) 12, 12a-12g Convex part 13, 13a-13g Concave part 14 Side surface 15, 15a to 15g, 15h Brick provided with unevenness 15 'Unevenness a, a' Depth of recess b Width of recess

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadami Ishihara 2-2-1 Otemachi, Chiyoda-ku, Tokyo Shinagawa Kawashiro Brick Co., Ltd. (72) Inventor Akira Ueno 2-2-2, Otemachi, Chiyoda-ku, Tokyo No.1 item Kawashira Brick Co., Ltd. F term (reference) 4G012 KA08 4K051 AA03 AA09 AB03 DA03 4K061 AA08 BA01 BA05 CA17 CA23 EA08

Claims (3)

[Claims] In a lining structure in which a furnace inner surface of a refractory lining of a rotary kiln is formed with irregularities, the lining refractory is made of a refractory brick, and a part or the entire surface of the refractory brick on the inner side of the furnace is irregular. A refractory lining for a rotary kiln, characterized by forming a part. 2. The rotary kiln lining according to claim 1, wherein the concave / convex portion has a concave portion having a depth of 10 to 50 mm and a width of 10 to 50 mm formed in a part of the inner surface of the furnace of the refractory brick. Refractory. 3. The refractory lining for a rotary kiln according to claim 1, wherein the concave and convex portion has a concave portion having a depth of 0.5 to 5 mm formed on the entire surface of the refractory brick on the inner side of the furnace.