JP2000026169A - Apparatus and method for executing castable refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method and apparatus capable of executing a castable refractory excellent in structural homogeneity and free from dripping without limitation of executing thickness and places and capable of shortening the executing time without needing labor and time so much. SOLUTION: In this method for executing the castable refractory, water for kneading is added to the castable refractory comprising at least one refractory aggregate selected from refractory aggregates such as alumina, mullite, chamotte, silicon carbide, a ceramic fiber bulk and silica, at least one binder selected from binders such as alumina cement, hydraulic alumina and gypsum to obtain a wet mixture, then the wet mixture is sprayed onto the place to be executed by adding an agent for inhibiting the dripping just before executing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for casting castable refractories.

[0002]

2. Description of the Related Art Castable refractories are used, for example, as preheaters for cement production equipment, tundishes for steelmaking casting vessels, ladle, and lining materials for industrial furnaces represented by billet heating furnaces and soaking furnaces. used.

Heretofore, castable refractories have been mainly constructed by casting, but in recent years, spraying has also been practiced.

[0004] Pouring is a construction method in which a formwork is previously installed at a construction site, castable refractories are poured into the formwork and vibrated by a rod-shaped vibrator or the like, similarly to building concrete.

On the other hand, as the spraying, dry spraying is mainly performed in which dry powder is conveyed by air, and water is added at the tip of a nozzle to perform the spraying.

[0006] This dry spraying construction does not require kneading or formwork such as pouring, so that the construction can be simplified and the working time can be greatly reduced. For this reason, dry spraying is being widely adopted for castable construction of a cement preheater, repair material construction of a molten steel container, and the like.

[0007]

However, in dry spraying, the material conveyed by high-pressure air is
Water is added at the nozzle mouth. For this reason, water may not be evenly distributed in the material, and the uniformity of the structure of the construction body may be inferior, or the work environment may be deteriorated due to dust generation.

[0008] In order to solve the drawbacks of such dry spraying, wet spraying in which wet spraying is performed has been proposed.

In the wet spraying method, since the refractory which has been slurried in advance by a mixer or the like is transported and sprayed, the uniformity of the structure and the working environment are improved as compared with the dry spraying method.

However, in this wet spraying method, there is a problem of sagging, so that there is a limit on the thickness of the construction. In addition, for example, there are restrictions on the construction site, such as difficulty in constructing the ceiling.

An object of the present invention is to solve the above-mentioned problems of the prior art, to reduce the time required for construction without the need for labor, to achieve excellent tissue uniformity, to prevent dripping, and to reduce the thickness of the construction. It is an object of the present invention to provide a method and an apparatus for constructing castable refractories having no restrictions on the construction site and construction site.

[0012]

One of the solutions of the present invention is to provide one or more refractory aggregates selected from refractory aggregates such as alumina, mullite, chamotte, silicon carbide, ceramic fiber bulk, and silica. Kneading water is added to the castable refractory, which is composed of one or more binders selected from binders such as alumina cement, hydraulic alumina, and gypsum, and the mixture is wetted, and this is applied to the construction site. This is a method for constructing a castable refractory, characterized in that spraying is performed, and a dripping prevention material is added immediately before the spraying.

Another solution of the present invention is a kneading section (11) for adding kneading water to a castable refractory containing a refractory aggregate and a binder, and transporting the castable refractory in a wet state. And a castable pressure feeding part (21) for spraying from the discharge member (14) to the construction site, and for adding a dripping prevention material to the wet castable refractory near (15) the discharge member (14). This is a castable refractory construction apparatus provided with a dripping prevention material addition section (31).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A method for constructing a castable refractory according to the present invention comprises the steps of: adding kneading water to a castable refractory comprising a refractory aggregate and a binder to form a wet state;
This is sprayed to the construction site, and a dripping prevention material is added immediately before the spray construction.

As the refractory aggregate, at least one selected from refractory aggregates such as alumina, mullite, chamotte, silicon carbide, ceramic fiber bulk, and silica is used.

As the binder, one or more binders selected from alumina cement, hydraulic alumina, gypsum and the like are used.

Specific examples of castable refractories include conventional castables in which alumina cement is added as a binder to a refractory aggregate, and alumina fine powder or silica fine powder added to a fine powder portion to reduce the content of alumina cement. Reduced high strength castables (low cement castables)
Also, there are high heat-resistant castables in which alumina cement is changed to hydraulic alumina, and heat-insulating castables in which aggregate is replaced with ceramic fiber bulk.

The reason why the anti-sagging material is added immediately before spraying is to eliminate the need for minute adjustment of the amount of the anti-sagging material and to prevent troubles hardening in the middle of the piping system. That is, it is not necessary to finely adjust the amount of the anti-sagging material in accordance with conditions such as the transport distance, time, temperature, and the like from kneading to construction.

According to the construction method of the present invention, excellent tissue uniformity and work environment can be enjoyed. In addition, since the thickness of the construction and the construction site are not limited, construction for a wide range of uses is possible.

As the sagging prevention material, a water-absorbing polymer or a mixture of a water-absorbing polymer and a curing accelerator can be used.

The water-absorbing polymer rapidly absorbs the kneading water, remarkably increases the viscosity of the castable refractory, and provides high adhesiveness.

As the water-absorbing polymer of the sagging prevention material, a granular or powdery acrylic water-absorbing polymer can be used.

The amount of the powdery water-absorbing polymer to be added is preferably 0.001 to 2% by weight in external ratio.

If the amount is less than 0.001% by weight,
Poor water absorption may cause dripping or falling off. On the other hand, when the amount exceeds 2% by weight, the structure of the sprayed body becomes porous and the strength properties may be reduced.

In the case of an acrylic water-absorbing polymer, the absorbability to a solution containing an electrolyte substance is affected by the type and concentration of the electrolyte. That is, in the neutral region, 5
It shows the maximum water absorption of 00 times, but the water absorption decreases on the acidic or alkaline side.

For this reason, the amount of the polymer to be added must be examined in some detail depending on the type of the binder. For example, when alumina cement is mainly used as a binder, the amount of addition of the polymer is inevitably large, and when hydraulic alumina is mainly used, the amount of addition is small.

The water-absorbing polymer refers to an acrylic water-absorbing resin.
It absorbs water 0 times and swells to become a gel. And once absorbed water does not release even if some pressure is applied.

As the setting accelerator to be mixed with the anti-sagging material, calcium hydroxide, lithium carbonate, sodium carbonate,
One or more selected from potassium carbonate and sodium aluminate can be used.

Since the setting accelerator reacts and hardens the sprayed construction body, the dripping prevention effect is enhanced. As a result, the construction thickness can be further increased.

The water-absorbing polymer and the setting accelerator can be used by mixing two or more kinds in advance with a predetermined composition. However, in the construction of a part such as a side wall or a hearth which does not necessarily require quick-hardening, there is no problem even if only the water-absorbing polymer is added and the setting accelerator is not added.

When both are mixed and added, the setting accelerator is preferably added in the form of a powder in an amount of 0.005 to 1% by weight.

In this case, if the amount is less than 0.005% by weight, the effect of accelerating the setting may not be sufficient. Conversely,
When the addition amount exceeds 1% by weight, the effect of accelerating the setting is too large, and it may be difficult to finish the surface of the construction body.

The casting apparatus for castable refractories according to the present invention conveys a castable refractory in a wet state, and a kneading section for adding kneading water to the castable refractory containing the refractory aggregate and the binder and kneading the mixture. A castable pressure-feeding section for spraying from the discharge member to the work site; and a dripping prevention material addition section for adding a dripping prevention material to the castable refractory in a wet state near the discharge member.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing one embodiment of a castable refractory construction apparatus according to the present invention.

The castable refractory construction apparatus 10 comprises a kneading unit 11, a castable pressure feeding unit 21, and a dripping preventing material adding unit 31.

The kneading section 11 can be constituted using a usual mortar mixer or the like. In the kneading section 11, kneading water is added to the castable refractory obtained by adding the binder to the refractory aggregate, and the mixture is kneaded to prepare a castable refractory in a uniform wet state.

The castable pumping section 21 includes the pumping device 12.
, A pipe 13, and a discharge member 14. Kneading part 1
The castable refractory in the wet state prepared in Step 6 is transported to the discharge member 14 by the castable pumping section 21, and spraying is performed from the discharge member 14 toward a work site.

As the pressure feeding device 12, a squeeze pump or a piston pump can be used.

The pipe 13 is an iron or rubber hose.

The discharge member 14 can be constituted by using a spray nozzle 14.

In front of the spray nozzle 14, a merging section 15
Is provided. The junction 15 connects the pipe 13 of the castable pressure feeding section and the pipe 18 of the dripping preventing material addition section 31.

The anti-sag material adding section 31 is for adding the anti-sag material to the castable refractory in a wet state. The sagging prevention material prevents the castable refractory material from dripping from the construction site.

The dripping preventing material adding section 31 is provided in the transport device 1
6, a pipe 18, and a compressed air source 17. The sagging prevention material inserted into the conveying device 16 is sent to the junction 15 by air pressure, where it is uniformly added to the wet castable refractory.

The spray nozzle 14 is arranged, for example, as shown in FIG. 1 toward the wall surface 19, and spraying is performed on a predetermined portion of the wall surface 19. The wall surface 19 is not particularly limited, and may be a side wall or a ceiling.

Examples 1 to 5 A refractory aggregate composed of at least one of alumina, mullite, chamotte, silicon carbide, magnesia, ceramic fiber bulk, fumed silica, and alumina cement and hydraulic alumina as binders Was added alone or in combination to obtain mixed powders of Examples 1 to 5. Table 1 shows their composition.

A predetermined amount of water was added to the obtained mixed powder and kneaded with a mortar mixer.

200 kg of this was put into the transfer pump hopper of the pressure feeding device, and the maximum discharge pressure was 5.0 M inside the metal hose.
It was conveyed at Pa, and a dripping inhibitor was added at the junction of the spray nozzle mouth. As shown in Table 1, a water-absorbing polymer and a powder obtained by mixing a water-absorbing polymer and a setting accelerator were used as the anti-sagging agent.
Added in ² .

The castable to which the anti-sagging agent was added was sprayed from the spray nozzle onto the wall of the simulated metal casing.

As a result, it was confirmed that all castables were free from material dripping and had a work thickness of 200 mm or more and good workability of 98% or more being adhered.

[0050]Comparative Examples 1 to 5  In the same manner as in Examples 1 to 5, a mixed powder having the composition shown in Table 1 was prepared.
It was prepared and sprayed under the same conditions as in Examples 1 to 5.
However, in Comparative Examples 1 to 5, it hangs down at the mouth of the spray nozzle.
No anti-fall material is added, or
It was added in a range outside the new amount.

As a result, poor construction such as dripping was observed.

[0052]

[Table 1]

[0053]

According to the method for constructing a castable refractory of the present invention, a uniform and high-strength construction can be obtained, and the service life can be extended twice or more as compared with a conventional dry spray construction. This is as durable as pouring.

Also, unlike the pouring work, the installation time of the mold and the curing time are not required, so that the working time can be reduced to 1/2 to １ ／ as compared with the pouring work.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an embodiment of a castable refractory construction apparatus according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 Castable refractory construction equipment 11 Castable refractory kneading part 12 Pumping device 13 Pipe 14 Discharge member 15 Merging part 16 Conveying device 17 Compressed air supply source 18 Pipe 19 Wall surface 20 Construction body 21 Castable refractory pressure feeding part 31 Anti-dripping material Transport unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (reference) C04B 103: 44 F term (reference) 4G012 MB23 MB26 PA03 PA11 PA12 PA14 PA15 PB03 PB04 PB08 PB11 PB31 PC04 PD02 PE04 4G033 AA02 AA06 AA10 AA12 AA17 AB01 AB02 AB12 AB23 BA01 BA02 4K051 LA02 LA12

Claims (7)

[Claims] At least one refractory aggregate selected from alumina, mullite, chamotte, silicon carbide, ceramic fiber bulk, and refractory aggregates such as silica, and a bond such as alumina cement, hydraulic alumina and gypsum. Kneading water is added to the castable refractory composed of one or more binders selected from the materials to make it wet, and this is sprayed to the work site, and immediately before the spraying work A method for constructing a castable refractory, comprising adding a sagging prevention material. 2. The method for constructing a castable refractory according to claim 1, wherein the sagging prevention material comprises a water-absorbing polymer or a mixture of a water-absorbing polymer and a curing accelerator. 3. The method according to claim 2, wherein the water-absorbent polymer is a granular or powdery acrylic water-absorbent polymer. 4. The method for constructing a castable refractory according to claim 3, wherein the amount of the powdery water-absorbing polymer to be added is 0.001 to 2% by weight. 5. The method according to claim 2, wherein the setting accelerator mixed with the water-absorbing polymer is at least one selected from calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate and sodium aluminate. The construction method of the castable refractory described. 6. The addition amount of the setting accelerator is 0.005 as an external ratio.
The method for constructing a castable refractory according to claim 5, wherein the amount is from 1 to 1% by weight. 7. A kneading section (11) for adding kneading water and kneading a castable refractory containing a refractory aggregate and a binder.
A castable pressure-feeding unit (21) for transporting the wet castable refractory and spraying it from the discharge member (14) to the work site; and a wet castable refractory near (15) the discharge member (14). A castable refractory construction apparatus comprising a dripping preventing material addition section (31) for adding a dripping preventing material to a thing.