JPH10316478A - Spraying work for dense monolithic refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of spraying work capable of giving dense monolithic refractories having a high density, mechanical strength and corrosion resistance without such problems as environmental aggravation due to rebound loss, deterioration of the quality of works due to moisture content increase, cumbersomeness of sweeping operation, and much waste of remaining materials. SOLUTION: This method of monolithic refractory composition spraying work using a spray machine comprises as follows: an air-carried monolithic refractory composition 12 is incorporated, before a spray nozzle 5, with such amounts of water and compressed air 9 for the work as to afford enough workability to be castable via a watering 1, and a flocculant or shape retentive agent 11 is added to the resultant composition at the spray nozzle part followed by conducting the objective spraying work; wherein the monolithic refractory composition comprises a dispersant and the main component composed of a refractory aggregate with particle size adjusted to <=10 mm, ultrafine refractory particles <=10 μm in size, and, as the case may be, cement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for spraying a dense amorphous refractory used as a lining material of a molten metal container such as a ladle, a tundish, a gutter or the like and an atmosphere furnace.

[0002]

2. Description of the Related Art In recent years, as the durability of a casting material has been improved, the lining material of a molten metal container has shifted from a brick to a casting material that can be easily constructed. However, with regard to labor saving, the casting method has a problem that the framing operation is still complicated. On the other hand, the spraying method does not require a formwork and allows for quick and local repairs, which contributes to further labor savings and allows for flexible repair plans. Therefore, the spraying method tends to increase.

[0003] The spraying method includes a dry spraying method, a semi-dry spraying method and a wet spraying method.

[0004] The dry spraying method is a method in which irregular refractory powder is conveyed to the tip of a spray nozzle by compressed air, and water is added at the nozzle portion to spray the powder. This method does not require a mixer for kneading and has advantages such as easy cleaning after use.However, the mixing of powder and water in the nozzle becomes uneven, so that the durability of the refractory material installed is reduced. There are problems such as inferiorness, rebound loss, and deterioration of the working environment due to dust generation. 58-137465 as a method to improve mixing of powder and water in the nozzle
No. and No. 58-137466. Both devices are of the same applicant, and in both cases, water is injected into the nozzle portion in two stages, and furthermore, the shape and arrangement of the water inlet at the tip portion are devised. However, after all, the mixing state of water and powder only within a short distance in the nozzle is still insufficient.

[0005] In the semi-dry spraying method, a part of the required construction water content is kneaded in advance with a powder of amorphous refractory by a mixer, and the mixture is pneumatically conveyed to a spraying nozzle using a dry spraying machine. In this method, the remaining solution or suspension containing water or a curing agent is added and sprayed. Examples of disclosure of this construction method include JP-A-61-111973 and JP-B-2-27.
No. 308, No. 6-17273, No. 5-63437, No. 5-21866. Although these construction methods show some improvement in terms of dust generation and reduction of rebound loss,
Basically, the water or aqueous solution and the material must be instantaneously mixed at the nozzle, so the degree of mixing is not good,
The amount of water is also easy to fluctuate. As a result, the adhesion of the spray material, the uniformity of the construction body, and the filling property are poor.

[0006] The wet spraying method is a method of spraying a mixture obtained by previously kneading the entire required amount of construction moisture with powder of an amorphous refractory. In this case, a small amount of an aqueous solution in which a curing modifier or a curing agent is dissolved may be added at the nozzle. Further, the wet spraying method is classified into an air conveying method and a pump conveying method according to a material conveying means.

[0007] Among the wet spraying methods, in particular, the dense refractory amorphous refractory composition is kneaded with water or other kneading liquid to adjust the workability of the softness, and is conveyed to a spray nozzle by a pressure pump. The method of performing wet spraying by adding a shape-retaining agent or coagulant in the form of an aqueous solution together with compressed air at the spray nozzle, compared to the conventional dry, semi-dry or wet spraying method, The applicant has previously filed several patent applications for such a wet spraying method (Japanese Patent Application Nos. 8-179913 and 8-179913). 269399 and Japanese Patent Application No. 8-293215
issue).

With regard to workability, the above-mentioned wet spraying method has the advantage that the rebound loss and dust generation are small, and the water amount adjustment depending on the skill of the nozzleman is not required, so that the work is stable. Regarding the quality of the construction body,
Since the structure of the construction body is uniform and dense, the corrosion resistance and strength are remarkably superior to those of the conventional spraying method, and are comparable to the cast construction body.

However, in any of the above-mentioned wet spraying methods, the material kneaded by the mixer is conveyed to the nozzle using an air carrier or a pressure pump. Cleaning and removing operations of the used materials are complicated, and these materials must be discarded without being used, which is uneconomical.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problems of the conventional dry spraying method and semi-dry spraying method (deterioration of environment due to rebound loss, deterioration of construction quality due to increased moisture, etc.) and the like. , The problems of the semi-dry and wet spraying methods (complexity of spraying process, troublesome cleaning, uneconomics due to large waste material disposal, etc.) are eliminated, It is an object of the present invention to provide a spraying method capable of obtaining a dense amorphous refractory having high density, high strength and high corrosion resistance in terms of water content.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that during transporting the powder of the amorphous refractory composition to the nozzle portion by air, the applied moisture is reduced to a high pressure. The present inventors have discovered that uniform addition of the amorphous refractory composition and water can be achieved in a short time by virtue of its strong stirring action when added using compressed air, thus completing the present invention.

That is, the spraying method of the present invention is a method of applying an amorphous refractory composition by a spraying machine, and pours the air-conveyed amorphous refractory composition through a water ring just before the spray nozzle. It is characterized by adding a working water amount and compressed air to obtain a soft workability, and further adding a coagulant or a shape-retaining agent at a spray nozzle to perform spraying.

The main components of the amorphous refractory composition used in the present invention are 70 to 98% by weight of a refractory aggregate adjusted to a particle size of 10 mm or less and 2 to 30% by weight of a refractory ultrafine powder having a particle size of 10 μm or less. , And a dispersant is added to the above main component in an amount of 0.01 to 1% by weight.

Furthermore, the main component of the amorphous refractory composition used in the present invention is a refractory aggregate 62 to 9 adjusted to a particle size of 10 mm or less.
A total of 100% by weight of 7.2% by weight, 2 to 30% by weight of a refractory ultrafine powder having a particle size of 10 μm or less and 0.8 to 8% by weight of cement, and 0.01 to 1% by weight of a dispersant is externally added to the main component. It is characterized by the following.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

[1] Method for Adding Water and Compressed Air An example of the embodiment of the present invention will be specifically described with reference to FIG. The added moisture 10 and the compressed air 9 are added from the appropriate addition position 3 in front of the nozzle of the pneumatic transport pipe 8 of the amorphous refractory composition.

(1-A) Compressed air The compressed air 9 to be added is adjusted by the pressure regulating valve 4 and supplied through the water ring 1 together with the water to be added from the water inlet 7. The pressure of the compressed air 9 adjusted by the pressure adjusting valve 4 may be any pressure as long as it is higher than the internal pressure of the material conveying pipe.
For normal construction of tundish, gutter, etc., 2 kgf / cm ² or more is desirable. As is clear from FIG. 2, which shows the relationship between the compressed air pressure and the optimum amount of added water necessary for the construction, 2 kgf / cm ²
At a pressure lower than this, the optimum amount of added water necessary for the construction is very large, and good workability cannot be obtained. This is because at a pressure of less than 2 kgf / cm ^2, air and moisture do not reach the center of the amorphous refractory composition conveyed by air, and the mixing of powder and water is insufficient. Therefore, in order to infiltrate the water to the central portion in the pipe, it is necessary to increase the amount of water to be added, but this causes a decrease in the strength of the construction body.

(1-B) Added Water The added water 10 is added from the water inlet 7 to the transport path in the compressed air 9. Any water can be used as the added water, such as tap water, industrial water and return water, as long as no harmful substances that adversely affect the curing properties are mixed. It is sufficient that the pressure of the added water is approximately the same as the ordinary tap water pressure. If the water pressure is higher than the pressure of the compressed air, it can be added as it is. However, if the pressure is lower than the compressed air, there is a risk of backflow. Therefore, it is desirable to add the water using the ejector 6.

The amount of added water is a very important factor for obtaining a dense amorphous refractory, and the denseness improves as the water content of the construction body is reduced and the mixture is more uniformly mixed. Since the amorphous refractory composition powder is applied by spraying, it is necessary that the fluidity required for spraying is secured. The wet spraying method, in which the water content of the pouring softness is added and the mixture is sufficiently kneaded with a mixer, is an excellent method from this point of view, but has the drawback of complicated cleaning and a large amount of waste material as described above. have. The present invention can be carried out with the same moisture as the wet spraying method, and eliminates the disadvantages of the wet spraying method.

The amount of water added is defined as the amount of water that can be applied to the pneumatically-conveyed amorphous refractory composition to obtain the workability of the softness. The amount of water at which the workability of pouring softness is obtained is greatly affected by the particle size composition of the amorphous refractory composition used, the porosity of the refractory aggregate, and the like. In the present invention, the suitable amount of construction moisture is 4.5 to 9.0% by weight on the basis of 100% by weight of the amorphous refractory composition. If the added water content is less than 4.5% by weight, the flowability of the construction material is insufficient and unevenness of construction occurs, and if it exceeds 9.0% by weight, the workability of spraying such as running down is reduced and the strength of the construction body is reduced. Preferably it is 5.0 to 8.5% by weight.

(1-C) Addition position of water and compressed air A mixture of water and compressed air is added via a water ring 1 from a proper addition position 3 provided in the irregular shaped refractory composition conveying pipe 8. Appropriate addition position 3 is 1-5 before spray nozzle
m. As is clear from FIG. 3, which shows the relationship between the addition position of the mixture of moisture and compressed air and the amount of added water at which good workability is obtained, when the addition position is less than 1 m, the amorphous refractory composition is mixed with water. Due to lack of time, good workability cannot be obtained with a small amount of water. In order to obtain good workability even at less than 1 m, it is necessary to increase the amount of water added,
The strength of the refractory after construction decreases. Good mixing can be obtained when the addition position is 1 m or more. However, when the addition position is more than 5 m, the cleaning range of the transport pipe after the end of the operation is increased, which is complicated, and waste material is increased, which is uneconomical.

(1-D) Others The conveying pipe 8 for the amorphous refractory composition may be any conventional conveying pipe made of metal, rubber or synthetic resin. The water and the compressed air are supplied by the water ring 1 into the irregular shaped refractory composition powder in the transfer pipe 8.
It is more convenient to handle the transport pipe of the wet body to which the moisture and the compressed air are added by using a flexible pipe made of rubber or the like. The addition of the coagulant or the shape-retaining agent 11 is performed by the water ring 2 installed in the nozzle unit 5. These are preferably added in the form of an aqueous solution.

[2] Amorphous refractory composition In the present invention, any of an amorphous refractory composition containing no cement and an amorphous refractory composition containing cement can be used.

(2-A) In the case of the cement-free amorphous refractory composition The cement-free amorphous refractory composition contains, as a main component,
It contains (a) refractory aggregate and (b) ultrafine refractory powder, and
(c) It contains a dispersant.

(2-Aa) Fire-Resistant Aggregate The fire-resistant aggregate used in the present invention is electrofused alumina, sintered alumina, bauxite, kyanite, andalusite, mullite, chamotte, rhoite, silica stone, alumina −
It is at least one selected from the group consisting of magnesia spinel, magnesia, zircon, zirconia, silicon carbide, graphite, pitch, and the like, and two or more types can be used in combination as needed. The particle size of the refractory aggregate is 10 mm or less.
If it exceeds 10 mm, the reband loss during construction will increase. The blending amount of the refractory aggregate is preferably 70 to 98% by weight, more preferably 75 to 95% by weight, per 100% by weight of the refractory aggregate and the refractory ultrafine powder.

(2-Ab) Refractory Ultrafine Powder The refractory ultrafine powder is a group consisting of ultrafine powders of alumina, amorphous silica, silica, alumina, titania, mullite, zirconia, chromia, silicon carbide, carbon, clay and the like. Use at least one selected from
More than one species can be used in combination. The particle size of the refractory ultrafine powder is
10 μm or less. If the particle size exceeds 10 μm, the water reducing effect due to the combined use with the dispersant is small. When the particle size is 1 μm or less, the water reducing effect is remarkable, and thus it is preferable.

The compounding amount of the refractory ultrafine powder is 2 to 30% by weight based on 100% by weight of the refractory aggregate and the refractory ultrafine powder. If it is less than 2% by weight, the water reducing effect is small, and if it exceeds 30% by weight, the amount of construction water increases and the shrinkage when heated and fired after the refractory construction is increased. The preferred amount of the refractory ultrafine powder is 5 to 25% by weight.

(2-Ac) Dispersant As the dispersant, an alkali metal salt of condensed phosphoric acid such as sodium hexametaphosphate and an alkali metal salt of silicic acid, or an organic acid such as carboxylic acid, humic acid, alkylsulfonic acid and aromatic sulfonic acid can be used. One or more of acids and alkali metal salts thereof are used. The amount of dispersant added is irregular refractory composition 100
It is 0.01 to 1% by weight based on the weight%. If the added amount of the dispersant is less than 0.01% by weight, a sufficient dispersing effect on the refractory ultrafine powder cannot be obtained, and if it exceeds 1% by weight, an optimum dispersion state cannot be obtained. A preferred amount of the dispersant is 0.03
0.8% by weight.

(2-Ad) Other components Other components that can be blended with the amorphous refractory composition include:
Fibers such as inorganic or metal for improving the strength, metal aluminum powder as an anti-explosion agent at the time of drying, oxycarboxylates, and organic fibers are available. More metal silicon,
Powdery sintering aids such as ferrosilicon and antioxidants such as boron carbide can also be used.

[2-B] In the case of the amorphous refractory composition containing cement The amorphous refractory composition containing cement includes (a) a refractory aggregate, (b) a refractory ultrafine powder, and (c) It contains a main component consisting of cement and (d) a dispersant.

(2-Ba) Refractory aggregate The type and particle size of the refractory aggregate used in the present invention are (2-Aa)
It is the same as described in. The amount of refractory aggregate is from 62 to 100% by weight of refractory aggregate + refractory ultrafine powder + cement.
97.2% by weight. For the same reason as described above, the preferred amount of the refractory aggregate is 69 to 94% by weight.

(2-Bb) Refractory ultrafine powder The type and particle size of the refractory ultrafine powder are the same as those described in (2-Ab). The compounding amount of the refractory ultrafine powder is 2 to 30% by weight per 100% by weight of refractory aggregate + refractory ultrafine powder + cement. Further, for the same reason as described above, the preferable amount of the refractory ultrafine powder is 5 to 25% by weight.

(2-Bc) Cement Cement is added to improve the strength of the construction body. Any kind of cement can be used as long as it is useful for improving the strength, but it is preferable to use alumina cement from the viewpoint of fire resistance. Alumina cement is JI
S Classes 1, 2, and 3 are suitable. The amount of cement is 0.8 to 8% by weight per 100% by weight of refractory aggregate + refractory ultrafine powder + cement. If it is less than 0.8% by weight, the effect of improving strength is not sufficient, and if it exceeds 8% by weight, the corrosion resistance of the construction body is greatly reduced. Preferably it is 1 to 6% by weight.

(2-Bd) Dispersant The type of dispersant is the same as described in (2-Ac). The amount of dispersant added is refractory aggregate + refractory ultrafine powder + cement 10
It is 0.01 to 1% by weight per 0% by weight. Further, for the same reason as described above, the preferable addition amount of the dispersant is 0.03
0.8% by weight.

(2-Be) Other components Other components that can be blended with the amorphous refractory composition include (2-A-
As described in d), there are fibers such as inorganic and metal for improving strength, metal aluminum powder as an anti-explosion agent, oxycarboxylate and organic fibers. Further, there are powdery sintering aids such as metallic silicon and ferrosilicon and antioxidants such as boron carbide.

[3] Coagulant and Shape Retaining Agent (3-A) Coagulant H ⁺ , OH ^- ion or Mg ²⁺ , B
divalent or trivalent cations or anions such as a ²⁺ , Ca ²⁺ , Al ³⁺ , SO ₄ ²⁻ , CO ₃ ²⁻ , Cr ₂ O ₇ ²⁻ (opposite to the surface charge of the refractory ultrafine powder) It is preferable to use an electrolyte that elutes), for example, magnesium chloride, calcium chloride, barium chloride, aluminum chloride, magnesium sulfate, aluminum sulfate, aluminum nitrate, sodium sulfate, potassium dichromate, Examples include calcium hydroxide, sulfuric acid, and sodium hydroxide.

It is considered that the model of the aggregation mechanism of the present invention corresponds to isoelectric aggregation (charge neutralization type aggregation) and Schultz-Hardy type aggregation. In addition, in most cases, hydrogen ions (or hydroxide ions) are potential determining ions in metal oxides. However, aggregation caused by adding a small amount of potential determining ions to annihilate the repulsive force of the electric double layer is considered. Isoelectric coagulation. In addition, the electrolyte does not affect the particles at all (by adsorption, etc.), but increases the ionic strength of the medium, compresses the electric double layer of the particles, and causes the electric repulsion to be relatively weaker than the cohesion. Schult agglutination
It is called z-Hardy type coagulation or simply coagulation. Agglomerates formed by Schultz-Hardy type condensation are relatively dense.

In the present invention, these coagulants are added to a wet material obtained by adding moisture and compressed air to an amorphous refractory composition at a blowing nozzle. The flocculant is preferably used in the form of an aqueous solution. The addition amount of the aqueous coagulant solution depends on the concentration of the solution, but the irregular refractory composition (refractory aggregate + refractory ultrafine powder,
Or refractory aggregate + refractory ultrafine powder + cement) 100% by weight
On the other hand, 0.1 to 1.5% by weight is appropriate. If the amount of the coagulant added is less than 0.1% by weight, the coagulation effect is small,
If it exceeds 1.5% by weight, the compactness of the construction body will be reduced. The preferred addition amount of the flocculant is 0.2 to 1.3% by weight. The addition of the aqueous coagulant solution is preferably supplied by a metering pump that operates in synchronization with the amount of the amorphous refractory composition.

The concentration of the aqueous coagulant solution is preferably 20 to 50% by weight. Therefore, the amount of the coagulant added on a solid basis is preferably 0.02 to 0.75% by weight. If the amount of coagulant added (based on solid content) is less than 0.02% by weight, the coagulation effect is small, and if it exceeds 0.75% by weight, the denseness of the structure of the construction decreases (the bulk density of the construction decreases). A more preferable addition amount (based on solid content) of the flocculant is 0.03 to 0.5% by weight.

(3-B) Shape Retaining Agent In the present invention, an alkali silicate, an alkali aluminate, or the like can be used as the shape retaining agent instead of the above-mentioned coagulant. The shape-retaining agent imparts the function of eliminating the fluidity of the water-containing irregular-shaped refractory composition at the moment of spraying and imparting shape retention. It is preferable to use an alkali silicate or an alkali aluminate as the shape-retaining agent. This shape-retaining agent is preferably added in the form of an aqueous solution.

As the alkali silicate, SiO ₂ / R ₂ O (however,
Preferably, the molar ratio of R ₂ O is an alkali metal oxide) is 2.0 to 3.3. The alkali aluminate preferably has a molar ratio of R ₂ O / Al ₂ O ₃ (where R ₂ O is an alkali metal oxide) of 1 to 3.

The amount of the shape-retaining agent to be added is affected by the working surface temperature and needs to be increased as the working surface temperature increases. 0.1 to 1% by weight. If it is less than 0.1% by weight, the effect of imparting shape retention is small, and if it is 1% by weight or more, the alkali component increases and the corrosion resistance decreases. The preferred amount of the shape-retaining agent is 0.15 to 0.8% by weight.

When the shape-retaining agent is used in the form of an aqueous solution, its concentration is suitably from 25 to 50% by weight. The addition of the aqueous solution of the shape-retaining agent is preferably supplied by a metering pump synchronized with the amount of the amorphous refractory composition.

[0044]

The present invention will be described more specifically with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

Examples 1 to 6 and Comparative Examples 1 to 8 The spray application method of the present invention was compared with the conventional dry application method, semi-dry application method and wet application method. The composition of the amorphous refractory composition used is as shown in Table 1.

Table 1 Composition No. component ratio (% by weight) 1 2 3 [A] Refractory aggregate fused alumina (more than 5 mm) ⁽¹⁾ 17 17-fused alumina (5 mm or less) ⁽²⁾ 35 35 40 Fused alumina (1 mm or less) ⁽³⁾ 16 16 18 Silicon carbide ⁽⁴⁾ 18 18 18 Pitch ⁽⁵⁾ 2 2 2 [B] Refractory ultrafine powder Alumina ultrafine powder ⁽⁶⁾ 5 8 10 Amorphous silica ^{(7 )} 3 3 3 Carbon black ⁽⁸⁾ 1 1 1 Clay ⁽⁹⁾ 1-2 [C] Alumina cement ⁽¹⁰⁾ 206 Total of [A] + [B] + [C] 100 100 100 Dispersant Hexametaphosphoric acid Soda ⁽¹¹⁾ 0.1 0.1-Others Metallic aluminum ⁽¹²⁾ 0.5 0.5 0.5 Notes: (1) Particle size is more than 5mm and less than 10mm, unit: wt%. (2) Particle size of more than 1 mm and 5 mm or less, unit: weight%. (3) Particle size 1 mm or less, unit: wt%. (4) Particle size of 150 μm or less, unit: wt%. (5) Particle size 1 mm or less, unit: wt%. (6) Particle size 10 μm or less, unit: wt%. (7) Particle size 1 μm or less, unit: weight%. (8) Particle size 1 μm or less, unit: weight%. (9) Particle size 10 μm or less, unit: wt%. (10) Class 1 JIS, unit: wt%. (11) Particle size 0.5 mm or less, unit:% by weight (outside). (12) Particle size 0.5mm or less, unit: wt% (outer coat).

Using the amorphous refractory compositions shown in Table 1, the method of the present invention and the conventional method were used. Table 2 shows the construction method, the types and amounts of the coagulant and the shape-retaining agent used, and the properties of the construction body after construction.

Table 2 Examples Working method 1 2 3 4 5 6 Amorphous refractory composition ⁽¹⁾ Formula 1 Formula 1 Formula 2 Formula 2 Formula 2 Formula 2 Working method ⁽²⁾ The present invention The present invention The present invention The present invention Present invention Moisture addition position (m) ⁽³⁾ 1.5 2.0 2.0 2.0 3.0 3.0 Moisture content (%) ⁽⁴⁾ 5.5 5.3 5.1 5.1 5.1 5.1 Compressed air pressure for moisture addition ⁽⁵⁾ 3.0 3.0 3.0 3.0 3.0 3.0 agent sodium silicate aqueous solution ⁽⁶⁾ 0.2 - 0.2 - - - coagulant ⁽⁷⁾ CaCl ₂ aqueous solution - 0.5 - 0.5 - - MgSO ₄ solution - - - - 0.6 - AlCl ₃ solution - - - - - 0.7 construction of characteristics ^{( 8)} Bulk specific gravity (1000 ° C) 2.85 2.87 2.84 2.82 2.87 2.85 Bulk specific gravity (1500 ° C) 2.88 2.89 2.86 2.88 2.90 2.89 Hot bending strength 25 28 29 33 31 30 Waste material disposal amount ⁽⁹⁾ 1.00 1.21 1.25 1.20 1.24 1.22 Rebound loss ⁽¹⁰⁾ ○ ○ ○ ○ ○ ○

[0049] Table 2 (continued) Comparative Example construction methods 1 2 3 4 monolithic refractory composition ⁽¹⁾ Formula 3 Formula 1 Formula 2 Formula 1 construction method ⁽²⁾ Dry Dry Dry half dry moisture addition position (m) ^{(3 )} 0 0 0 0 Water content (%) ⁽⁴⁾ 11.0 9.5 9.0 7.8 (1.9) Compressed air pressure for water addition ⁽⁵⁾ ----Shape retention agent Sodium silicate aqueous solution ⁽⁶⁾ -0.2 0.2 0.2 Coagulant ⁽⁷⁾ CaCl ₂ aqueous solution----MgSO ₄ aqueous solution----AlCl ₃ aqueous solution---- Characteristics of the construction ⁽⁸⁾ Bulk specific gravity (1000 ° C) 2.66--2.70 Bulk specific gravity (1500 ° C) 2.67-- 2.71 Hot bending strength 10 − − 13 Waste material waste ⁽⁹⁾ 0.35 0.38 0.35 9.2 Rebound loss ⁽¹⁰⁾ ▲ ▲ ▲ △

[0050] Table 2 (continued) Comparative Example construction methods 5 6 7 monolithic refractory composition ⁽¹⁾ Formula 2 Formula 1 Formula 2 construction method ⁽²⁾ semi-dry wet wet moisture addition position (m) ⁽³⁾ 2.0 - - added water content (%) ⁽⁴⁾ 7.5 5.3 5.1 (1.9) water added for compressed air ⁽⁵⁾ - - - shape retention imparting agent sodium silicate aqueous solution ⁽⁶⁾ 0.2 0.2 - coagulant ⁽⁷⁾ CaCl ₂ aqueous solution - - 0.5 MgSO ₄ solution - - - AlCl ₃ solution - - - characteristics of the construction body ⁽⁸⁾ bulk density (1000 ° C.) 2.58 2.85 2.87 bulk density (1500 ° C.) 2.64 2.87 2.88 amount of waste hot flexural strength 16 28 30 residual material ⁽⁹⁾ 9.45 9.88 9.18 Rebound loss ⁽¹⁰⁾ △ ○ ○

Note (1) Formulation of the amorphous refractory composition shown in Table 1. (2) The contents of each indication of the construction method are as follows. The present invention: the spraying method of the present invention. Dry type: Dry spraying method (conveying gas to the nozzle, adding water at the nozzle and constructing with carrier air). Semi-dry type: Semi-dry spraying method (approximately 25% by weight of the total added water is added and mixed by a kneading machine, air-conveyed, and about 75% by weight of the remaining water is added at the nozzle or just before the nozzle. Add a shape-retaining agent or coagulant and work with carrier air). Wet type: Wet spraying method (add water and mix with a kneader, pump by pump, add additive or coagulant together with compressed air at nozzle part, and work with compressed air.) (3) Water addition position Is represented by a distance (unit: m) from the nozzle portion. The present invention: the distance before the nozzle portion. Dry spraying method: added at the nozzle (0 m). Semi-dry spraying method: The remaining water content is added at the nozzle portion and just before the nozzle (0 m). Wet spraying: Water is mixed in advance and transported by a pump (-). (4) Moisture content that can be applied: wt% (amorphous refractory composition
Outside weight for 100% by weight. In the case of the semi-dry spraying method, the value in the parentheses is the premix moisture content). (5) Unit: kgf / cm ² . (6) Concentration 35%, unit:% by weight (based on solid content, externally applied). (7) Concentration 2.7 mol / liter, unit:% by weight (outside). (8) After the construction, the construction was cut out and measured. Bulk specific gravity (no unit): Measured after firing based on JIS-R2553. Hot bending strength (unit: kgf / cm ² ): measured at 1500 ° C. (9) Relative weight ratio when Example 1 is set to 1.0. (10) Evaluation was made based on the following criteria. ：: Rebound loss is small and good. Δ: Rebound loss is slightly large and slightly poor. ▲: Many rebound loss, poor.

Examples 1 to 6 are the results of the present invention,
The amount of water addition required for construction was small, and the strength of the construction body after construction was sufficient. In addition, the amount of residual material after construction is small and rebound loss is small.

On the other hand, Comparative Example 1 is an experimental example by a conventional dry spraying method using Formulation 3. However, since the mixing state of powder and water is poor, the required amount of water becomes extremely large.
The strength of the construction body was insufficient. Although the amount of residual material after construction was small, the reband loss was large and it was defective. Comparative Examples 2 and 3 are experimental examples using Formulations 1 and 2 containing a dispersant. Although the required water content is slightly reduced as compared with the conventional dry spraying method (Comparative Example 1), the mixing state is still poor.
Since the excess water portion and the powder portion coexist, the material peeled off on the construction surface despite the addition of the shape-retaining agent, making construction impossible.

Comparative Example 4 is an experimental example using the semi-dry spraying method, but the required amount of water is slightly large and the strength of the construction body is not sufficient. In addition, the amount of residual material after construction was extremely large. Comparative Example 5 is an experimental example in which water was added in front of the nozzle by a semi-dry spraying method. However, since the mixing of water was not sufficient, the required amount of water was large and the strength of the construction body was not sufficient. Also, the amount of residual material waste is very large. Comparative Examples 6 and 7 are experimental examples by the wet spraying method, in which the required water content was small and the strength of the construction body was sufficient, but the amount of remaining material after construction was extremely large.

Example 7 Using the amorphous refractory composition of Formulation 2, spraying was carried out under the same conditions as in Example 6 except that the compressed air pressure was changed. The optimum amount of added water necessary for the construction at each compressed air pressure was determined.
The results are shown in FIG. As is clear from FIG. 2, 2 kgf / cm
^When the pressure became less than ^{2, the} optimum amount of added water required for the construction greatly increased.

Example 8 Using the amorphous refractory composition of Formulation 2, spraying was performed under the same conditions as in Example 3 except that the position of addition of the mixture of moisture and compressed air was changed by the apparatus shown in FIG. The optimum amount of added water necessary for the construction at each water addition position was determined. The results are shown in FIG. As is clear from FIG. 3, when the addition position was less than 1 m, the optimum amount of added water required for construction increased.

[0057]

As described in detail above, the spraying method of the present invention can be applied to a cement-free amorphous refractory composition having a conventional particle size composition and composition or a cement-containing amorphous refractory composition. The powder to which the agent has been added is conveyed by air and poured through a water ring before the spray nozzle, and the amount of water that provides soft workability is added with high-pressure compressed air. Alternatively, a coagulant is added for construction. According to the construction method of the present invention, problems such as a conventional dry construction method and a semi-dry spray method, such as deterioration of the environment due to rebound loss and deterioration of the construction body due to increased moisture, and a complicated blowing device, or cleaning The problems with wet spraying and semi-dry spraying, such as troublesome and large amounts of residual material, have been solved. Irregular refractories are obtained.

[Brief description of the drawings]

FIG. 1 is a construction procedure diagram schematically showing an example of a spraying construction method of the present invention.

FIG. 2 is a graph showing the required amount of added water to obtain fluidity that allows the amorphous refractory composition to be applied when the added compressed air pressure is changed.

FIG. 3 is a graph showing a relationship between a water addition position and a required amount of added water for obtaining fluidity that enables the amorphous refractory composition to be applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Watering 2 ... Water ring 3 ... Moisture and compressed air addition hole 4 ... Compressed air pressure adjustment valve 5 ... Spray nozzle 6 ... Ejector 7 ... Water addition hole 8 ... irregular-shaped refractory composition transport pipe 9 ... compressed air 10 ... moisture 11 ... flocculant or shape-retaining agent 12 ... irregular-shaped refractory composition

Claims (6)

[Claims] 1. A method of applying an amorphous refractory composition by a spraying machine, wherein the moisture is poured into the air-conveyed amorphous refractory composition through a water ring in front of a spray nozzle to obtain soft workability. A spraying method comprising adding an amount and compressed air, and further adding a coagulant or a shape-retaining agent at a spray nozzle to perform spraying. 2. The spraying method according to claim 1, wherein the main component of the amorphous refractory composition is 70 to 98% by weight of a refractory aggregate whose particle size is adjusted to 10 mm or less, and the refractory material has a particle size of 10 μm or less. A spraying method, comprising a total of 100% by weight of 2 to 30% by weight of an ultrafine powder, and further adding 0.01 to 1.0% by weight of a dispersing agent to the main component. 3. The spraying method according to claim 1, wherein the main component of the refractory composition is 62 to 97.2% by weight of a refractory aggregate whose particle size is adjusted to 10 mm or less, and the refractory has a particle size of 10 μm or less. Spraying characterized by comprising a total of 100% by weight of 2 to 30% by weight of a water-soluble ultrafine powder and 0.8 to 8% by weight of cement, and further adding 0.01 to 1% by weight of a dispersing agent to the above-mentioned main component. Construction method. 4. The spraying method according to claim 1, wherein an alkali silicate or an alkali aluminate is added as the shape-retaining agent. 5. The spraying method according to claim 1, wherein the pressure of the compressed air is 2 kgf / cm ² or more. 6. The spraying method according to claim 1, wherein a position where the moisture and the compressed air are added is 1 to 5 m before the spray nozzle. Installation method.