JPH11199338A - Refractory for spraying repair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit accurate spray repair, thus sufficiently manifests the role of life prolongation for refractory by formulating a specific amount of carbon fiber to the raw materials for refractory and using a specific amount of an acidic sol solution as a binder. SOLUTION: This refractory for spray repair comprises 100 pts.wt. of raw materials for refractory with the maximum particle size of <=5 mm, 0.05-1 pts.wt. of carbon fiber, as the powdery components, and 1-10 pts.wt. of an acidic sol solution, as the liquid component. The raw material for refractory is at least one selected from the group consisting of alumina, silicon carbide, bauxite, chamotte, graphite and clay. The carbon fiber is preferably carbon fibers and/or graphite fibers of 2-7 mm length. The liquid component is, for example, alumina sol, silica sol, mullite sol and the like. In the wet type spraying repair, an alkali silicate salt solution with a pH of 8-13 is added to the repairing material and they are sprayed to the repairing sites.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a molten metal contact surface such as an inner surface of a tundish, an inner surface of a ladle, and a surface of a blast furnace tapping gutter;
The present invention relates to a refractory for spraying and repairing a hot gas contact surface such as a furnace wall of various processing furnaces such as a heating furnace and an annealing furnace, and a method therefor.

[0002]

2. Description of the Related Art Refractories constituting metal contact surfaces of molten metal containers and high temperature gas contact surfaces such as furnace walls of various processing furnaces are sprayed, poured, and patched regularly or when necessary. The repair method is carried out according to the above method, and the life of the refractory is extended.

[0003] Among these repair methods, the spraying method is widely used because unlike the pouring method, a large-scale repair can be performed in a short time without requiring an intermediate frame for construction. ing.

[0004] The spraying method is roughly divided into a dry method and a wet method.

[0005] In the case of the dry method, the compounded refractory powder is conveyed in a hose accompanied by high-pressure air, and water is added through a spray nozzle or mixed with a binder solution and sprayed at a construction site. The problem with the dry method is that it involves the generation of dust and a lot of rebound loss.

On the other hand, in a wet spraying method in which a slurry-like refractory material kneaded in advance is injected into a spraying machine or a compression pump and the inside of a hose is pressure-fed, a liquid binder for quick-setting is added and mixed at a nozzle portion. Has been done since ancient times. However, in this method, since the refractory material and the binder are not sufficiently mixed in the nozzle portion, the sprayed refractory material flows down from the sprayed repair portion, and the predetermined repair thickness and smoothness cannot be secured. And other troubles may occur.

[0007]

SUMMARY OF THE INVENTION The present invention solves or alleviates the problems of the prior art as described above, enables accurate spray repair, and is intended for the purpose of spray repair refractories. The main purpose is to fully fulfill the role of a refractory as a life extension treatment.

[0008]

As a result of repeated studies in view of the problems of the prior art, the present inventor has found that carbon fibers are used as a refractory raw material when repairing a predetermined repaired portion by wet spraying. It has been found that in the case of blending, the refractory material is prevented from running off and a predetermined repair thickness can be secured.

That is, the present invention provides the following spray repair refractory and spray repair method: Powder component and acid sol solution 1 to 100 parts by weight of refractory raw material having a maximum particle diameter of 5 mm or less and 0.05 to 1 part by weight of carbon fiber
Refractory for spray repair consisting of 10 parts by weight of liquid components.

[0010] 2. Refractory raw materials are alumina, silicon carbide,
Item 2. The spray repair refractory according to Item 1, which is at least one member selected from the group consisting of bauxite, chamotte, graphite, and clay.

3. Item 2. The spray repair refractory according to Item 1, wherein the carbon fiber is a carbon fiber having a length of 2 to 7 mm and / or a graphitized carbon fiber.

4. When performing wet spray repair using the refractory for spray repair according to item 1 above, an alkali silicate solution having a pH of 8 to 13 is added as a binder from a spray nozzle, and the refractory is rapidly bonded by a coagulation reaction. A spray repair method characterized by the following.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The spray repair refractories according to the present invention are of the conventional type except that a specific amount of carbon fiber is incorporated in the powder component and that an acidic sol solution is used as a binder. It is substantially the same as a wet repair refractory.

That is, regarding the powder component, first, at least one of the aggregate components such as alumina, silicon carbide, bauxite, chamotte, and spinel having a maximum particle diameter of 5 mm or less and the maximum particle diameter are determined according to the repaired part. A primary mixture is prepared by selecting at least one component of the fine powder part such as alumina fine powder, silicon carbide fine powder, graphite, clay, silica flour and the like having a particle size of 0.074 mm or less, adjusting the particle size, and mixing. The reason why the maximum particle size of the aggregate component is 5 mm or less is that when coarse particles are used, rebound loss at the time of spraying increases. The reason why the maximum particle diameter of the component of the fine powder is 0.074 mm or less is that when the maximum particle diameter is too large, the specific surface area of the fine powder relative to the aggregate is insufficient, and the required fluidity is obtained. It is not possible.

Next, carbon fiber having a length of about 2 to 7 mm and a diameter of about 6 to 8 μm was added to 100 parts by weight of the obtained primary blend to 0.0 parts by weight.
About 5 to 1 part by weight (more preferably about 0.1 to 0.8 part by weight) is added and mixed to obtain the powder component of the present invention. Alternatively, a powder component may be obtained by directly mixing a predetermined ratio of an aggregate component, a fine powder component, and carbon fiber.

As the carbon fibers, those commercially available as carbon fibers (carbonized fibers) or graphitized carbon fibers can be used. The reason for using such carbon fibers is that they are excellent in fire resistance and corrosion resistance in terms of material, and also excellent in wettability with molten metal. Entangled with the raw materials,
This is because the flow of the attached refractory material is prevented, and smoothness or shape retention is ensured. As carbon fiber,
Graphitized carbon fibers are more preferred.

When the amount of carbon fiber added to the total amount of the aggregate portion and the fine powder portion is excessive, the strength of the repaired portion is reduced, whereas when the amount is too small, the shape of the repaired portion is reduced. Is reduced. If the carbon fiber length exceeds 7 mm,
The fibers become entangled with each other, making it difficult to disperse them uniformly in the powder component (and eventually in the repair part).
If it is less than 2 mm, entanglement with the refractory raw material is not sufficiently performed.

As the liquid component, a known alumina sol (for example, about 10 to 11% as Al2O3 solid content), silica sol, mullite sol, or the like is used. These sols do not agglomerate even when kneaded with the powder component, and exhibit fluidity suitable for pressure feeding after kneading. In the present invention, the powder component 10
1 to 10 parts by weight of the liquid component is used for 0 parts by weight.

The spray repair method according to the present invention is usually carried out as follows.

First, an acidic sol solution and a predetermined amount of water are added to a powder component and kneaded to impart fluidity to the kneaded product. Further, in order to enhance the fluidity of the kneaded material, a known peptizer such as sodium hexametaphosphate and sodium pyrophosphate may be used in combination.

Next, the obtained fluidized kneaded material is sent out through a hose by a wet spraying machine or a compression pump, and a quick-setting binder component composed of an alkali salt solution is added and mixed at a spraying nozzle portion. Spray. By this operation, the acidic sol solution and the alkali salt solution react rapidly, causing the refractory to condense within a short time, so that dust generation can be prevented and rebound loss can be reduced.

As the quick-setting binder component, an alkali salt solution having a pH of 8 to 13 is used. As the alkaline salt solution,
An aqueous solution of sodium silicate, an aqueous solution of potassium silicate, or a water glass mainly containing these silicates may, for example, be mentioned. The amount of the quick-setting binder component may be appropriately determined according to the repair location, the composition of the sprayed refractory (particularly, the amount of the acidic sol solution), and is not particularly limited. It is about 0.5-3%.

[0023]

According to the present invention, substantially no dust is generated at the time of spray repair, and rebound loss is extremely reduced. Further, a uniform and sufficiently thick adhesion layer is formed on the repaired portion, the strength of the repaired portion is extremely high, and the surface is smooth.

[0024]

EXAMPLES Examples 1 to 7, Comparative Examples 1 to 4 (wet spraying method) and Comparative Example 5 (dry spraying method) are shown below to further clarify the features of the present invention.

Examples 1 to 7 An alumina sol solution (3 parts by weight of Nissan Chemical Industry Co., Ltd. and 5 to 6 parts by weight of water) was kneaded as a liquid component with respect to 100 parts by weight of a powder component having the composition shown in Table 1. A fluid kneaded material is prepared by using a compression pump (manufactured by Mustang Co., Ltd.) and sent to a nozzle portion, where 2 parts by weight of a JIS No. 3 water glass aqueous solution is mixed, and a 1.2 m height × 1.8 m width is mixed. Graphite carbon fibers (trade name “Treca chop fiber T-008”, manufactured by Toray Industries, Inc.) were used as the carbon fibers.

Table 2 shows the results of the spray test.

Further, the obtained composition is 40 mm × 40 mm × 160 m
m mould, spray cured for 24 hours, demolded, 110
Table 3 shows the physical properties of the prisms dried at 24 ° C. for 24 hours.

Comparative Examples 1 to 4 Comparative Examples 1 to 4 in which any of the provisions relating to the materials used in Table 1 were outside the scope of the present invention (see below) were prepared in the same manner as in Examples 1 to 7. The test was performed. The results are shown in Tables 2 and 3.

* Comparative Example 1: The maximum particle size of alumina is 8 to 5 mm
* Comparative Example 2: When the blending amount of carbon fiber is 2.0 parts by weight * Comparative Example 3: When the length of carbon fiber is 7 to 15 mm * Comparative Example 4: Refractory raw material is maximum When containing mullite coarse particles with a particle size of 8 to 5 mm.

Comparative Example 5 100 parts by weight of the powder material shown in Table 1 was conveyed to the spraying nozzle by compressed air using a dry spraying machine (lead gun manufactured by Pribrico), and 8 parts by weight of water was supplied to the nozzle. Was mixed and sprayed.

[0031]

[Table 1]

[0032]

[Table 2]

* Note 1: Fluidity flow value: JIS R5 of kneaded material
Value measured by 201 (mm).

* Note 2: Dust generation by spraying, hose passage property, nozzle discharge property, adhesion and swelling property were measured by applying 200 kg of each composition to an iron plate surface 1.2 m high x 1.8 m wide. It was sprayed by the method and evaluated by feel and appearance.

* Note 3: Rebound dross: When 200 kg of each composition was sprayed onto the surface of an iron plate having a height of 1.2 m and a width of 1.8 m, the weight of the object that rebounded and weighed was measured. ) / Test amount (200kg) × 10
0 was set.

[0036]

[Table 3]

* Note 4: All were measured according to JIS R2553.

[Consideration of Test Results] Examples 1 to 7
According to this, a composition having excellent fluidity, easy spraying operation, and low rebound loss is obtained. In particular, according to Examples 3 and 5, which use a relatively large amount of carbon fiber, extremely good results are obtained.

The composition of Comparative Example 1 contains coarse alumina particles having a particle size of 5 mm or more. In this case, since the liquid component is added and kneaded in advance, unlike the case of the dry method, there is no generation of dust and relatively little rebound loss.
However, since the powder component contains coarse particles, compared to Example 3 of the present invention, the fluidity after kneading is low, the passability in the spray conveying hose is poor, and the rebound loss is also large. , Low strength.

In the composition of Comparative Example 2, since the amount of the carbon fiber was too large, appropriate fluidity could not be obtained, and the composition could not be conveyed by a wet method. there were.

The composition of Comparative Example 3 had a carbon fiber length of 7 m.
m or more, the carbon fibers are entangled, the fluidity flow value is low, the permeability in the spraying transfer hose is poor, and the strength of the dried product is low.

Since the composition of Comparative Example 4 contains mullite coarse particles having a maximum particle size of 5 mm or more, the flowability after kneading is lower than that of Example 5 of the present invention, and Passability is poor and there are many rebound dross.

In Comparative Example 5 by the dry method, rebound loss is extremely large.

On the other hand, according to the method of the present invention shown in Examples 1 to 7, the fluidity flow value is high, the spraying property is excellent, and the strength of the dried product is also excellent.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ax Tomiyoshi 111-1 Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd. Inside Kure Works (72) Inventor Noriyuki Inoue 56 God of Mifunemachiyama, Toyota-shi, Aichi Prefecture Japan Nippon Crucible Co., Ltd. Inside the Mifune Plant (72) Inventor Nobuyuki Izumoto 56 Mifunemachiyama God, Toyota City, Aichi Prefecture Japan Crucible Co., Ltd. Inside the Mifune Plant (72) Inventor Maki Kajiwara 56 Mifunemachi God, Toyota City, Aichi Prefecture 56 Japan Crucible Co., Ltd. in the factory

Claims (4)

[Claims] 1. A spray repair comprising a powder component comprising 100 parts by weight of a refractory raw material having a maximum particle diameter of 5 mm or less and 0.05 to 1 part by weight of carbon fiber and a liquid component of 1 to 10 parts by weight of an acidic sol solution. Refractory. 2. The refractory for spray repair according to claim 1, wherein the refractory raw material is at least one selected from the group consisting of alumina, silicon carbide, bauxite, chamotte, graphite and clay. 3. The spray repair refractory according to claim 1, wherein the carbon fiber is a carbon fiber having a length of 2 to 7 mm and / or a graphitized carbon fiber. 4. When performing wet spray repair using the spray repair refractory according to claim 1, an alkali silicate solution having a pH of 8 to 13 is added as a binder from a spray nozzle, and a coagulation reaction is performed. A spray repair method characterized by rapidly bonding refractories.