JP2000335979A - Wet blowing material and method for executing the same material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a web blowing material scarcely generating dust and rebound loss onto the surface to be blown at ordinary temperature or warm or hot temperature and capable of providing a dense executed body having high durability and high adhesive ratio and adhesive strength, and provide a method for executing the above material. SOLUTION: This wet blowing material is obtained by compounding a refractory composition comprising 70-90 wt.% refractory aggregate in which <=10 wt.% aggregate is controlled to have >10 mm particle diameter and >=90 wt.% aggregate is controlled to have 10 mm 20 μm particle diameter and 10-30 wt.% refractory ultrafine powder having <20 μm particle diameter with a silicic alkali metal salt and an orthophosphoric acid alkali metal salt or an orthophosphoric acid alkaline earth metal salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet spraying material used for a furnace wall of various kilns and a method of applying the same.

[0002]

2. Description of the Related Art A wet spraying material comprising pumping a refractory material containing a binder component which has been previously kneaded with water, mixing it with a coagulant solution at a nozzle attached to the end of a hose, and blowing with high-pressure air. The construction method using the method does not require the construction formwork such as the construction using the cast material, has a feature that the dust generation and the rebound loss are less than the construction method using the dry spray material, and a dense construction body can be obtained. .

As an application method using a wet spraying material, for example, Japanese Patent Application Laid-Open No. 9-250880 discloses that a mixture of an amorphous refractory powder and a solvent is pumped to a nozzle and hardened into the kneaded material in the nozzle. Disclosed is a method for spraying an amorphous refractory, which comprises mixing an accelerator and spraying the mixture with a pressurized air on a construction surface.

Japanese Patent Application Laid-Open No. Hei 10-118762 discloses that 0.5 to 7% by weight of a phosphate, 3 to 20% by weight of a flow aid, and a balance of refractory aggregate and fine powder. A first component obtained by kneading 100% by weight of the solid content with water, wherein the water is present in an amount sufficient to achieve a pumpable consistency of the kneaded first component. A non-slump phosphate bond castable composition comprising one component and a second component coagulant added to the first component during construction is disclosed.

However, the conventional construction method described in the above publication presupposes the construction at normal temperature, the surface temperature of the surface to be sprayed exceeds 105 ° C., and the water in the construction body is heated. It is materially difficult to reduce the peeling of the water vapor generated due to the gas pressure to a level at which there is no practical problem.

Japanese Patent Laid-Open Publication No. Hei 10-96591 discloses that when a dense amorphous refractory is sprayed on a heated work piece, the spray thickness of the first layer is 10 to 30 mm, A hot spraying method for dense amorphous refractories, characterized in that the spray thickness of each layer is 30 to 100 mm.

Further, Japanese Patent Application Laid-Open No. 10-118762 discloses a method for wet spraying a cast refractory composition, wherein the cast refractory composition has a refractory aggregate 70 to 98 whose particle size has been adjusted to a particle size of 10 mm or less. % By weight and 2 to 30% by weight of refractory ultrafine powder having a particle size of 10 μm or less.
Using a cement-free material in which 0.01 to 1.0% by weight of a dispersant is externally added to 00% by weight, the above-mentioned refractory is kneaded with water or another kneading liquid and then flown. The product adjusted to the workability of the indentation softness is transported to a spray nozzle by a pressure pump, and the compressed air is compressed by the spray nozzle together with an alkali silicate and / or an alkali aluminate shape-retaining agent 0.1 to 1. A wet spraying method is disclosed in which weight percent (outer coat) is added in the form of an aqueous solution and spraying is performed. It is also described that an alkali silicate or an alkali aluminate is used as a shape-retaining agent, and in the description of the acidic dispersant, although hot working is referred to, basic examples including examples are also included. In general, it is assumed that the construction is carried out at normal temperature, and the addition rate of the shape-retaining agent is kept to a minimum necessary for exhibiting such strength that the water vapor pressure does not droop at room temperature below atmospheric pressure.

Japanese Unexamined Patent Publication (Kokai) No. 10-17374 discloses an amorphous refractory material used for wet hot spraying, such as MgO, CaO, Al ₂ O ₃ , SiO ₂ , or the like. A refractory aggregate composed of a combination of at least two or more species and a binder, wherein the refractory aggregate contains 10 wt% of a refractory material having a particle size of 45 μm or less.
~ 35 wt%, wherein the binder comprises at least 2
Disclosed is an amorphous refractory material for wet hot spraying, comprising an orthophosphate of a kind and an alkali silicate anhydride.

Furthermore, Japanese Patent Publication No. 45-12503 discloses mainly about 67 to 73% by weight of refractory particles not passing through a 100 mesh sieve, about 0.1% by weight of a plasticizer,
About 1-5% by weight of sodium dihydrogen orthophosphate and up to about 25% by weight of an active alkaline earth metal oxide containing compound passing through a 100 mesh sieve, wherein said alkaline earth metal oxide containing compound is At least sufficient to provide an alkaline earth metal oxide in an amount sufficient to react with half of the sodium dihydrogen orthophosphate to form the alkaline earth metal monohydrogen orthophosphate; Is comprised of inert refractory particles that pass through a 100 mesh sieve.

In Japanese Patent Publication No. 55-6598,
Gun spraying with sodium hexametaphosphate 1.5 to 5.5% by weight, slaked lime 0.1 to 10% by weight as CaO, no plasticizer, and the remainder as MgO, MgO-CaO-based basic aggregate Refractories are disclosed.

[0011]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a device having a high adhesion rate and a high adhesion strength with almost no dust or rebound loss on a surface to be sprayed at room temperature, warm or hot. An object of the present invention is to provide a wet spray material capable of obtaining a dense and highly durable construction body and a construction method thereof.

[0012]

That is, the present invention provides a 10 m
m is 10% by weight or less and the others have a particle size of 10 mm to 20 μm.
~ 90% by weight and a refractory ultrafine powder 1 having a particle size of less than 20 µm 1
A wet spraying material comprising a refractory composition containing 0 to 30% by weight of an alkali metal silicate and an alkali metal orthophosphate or an alkaline earth metal orthophosphate.

Further, the present invention provides the method for applying a wet spray material, wherein when the temperature of the surface to be sprayed is less than 105 ° C., the alkali metal silicate / alkali metal orthophosphate or the alkaline earth metal orthophosphate is used. The method for applying a wet spray material is characterized in that the addition ratio is more than 0.5 and less than 2.0.

Further, the present invention provides the method for applying a wet spray material, wherein when the temperature of the surface to be sprayed is 105 ° C. or more, the alkali metal silicate / alkali metal orthophosphate or the alkaline earth metal orthophosphate is used. The method for applying a wet spray material is characterized in that the addition ratio is 0.5 or less, or 2.0 or more.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The refractory aggregate used in the wet spraying material of the present invention comprises 1
Those having a particle size of more than 0 mm have a particle size of 10% by weight or less, preferably 5% by weight or less, and others have been adjusted to a particle size of 10 mm to 20 μm. The refractory aggregate is not particularly limited, but includes, for example, chamotte, rhorite, fused alumina, sintered alumina, bauxite, kyanite, andalusite, mullite, silica, spinel, magnesia, zircon, zirconia, One or more selected from the group consisting of silicon carbide and graphite can be used. In addition, the compounding ratio of the refractory aggregate having the above particle size configuration is in the range of 70 to 90% by weight, preferably 77 to 83% by weight.

The refractory ultrafine powder having a particle size of less than 20 μm used in the wet spraying material of the present invention is not particularly limited. For example, alumina, silica, mullite, titania, chromia, magnesia, zirconia, One or more of silicon carbide and carbon can be used. The mixing ratio of the refractory ultrafine powder is 10 to 30.
%, Preferably in the range of 17 to 23% by weight.
Here, when the blending ratio of the refractory ultrafine powder is less than 10% by weight, the adhesiveness of the kneaded material after kneading the materials is not preferable. On the other hand, if the mixing ratio exceeds 30% by weight, the flow resistance of the kneaded material increases, and it is necessary to add a large amount of water to suppress the flow resistance. It is not preferable because it cannot be formed.

Further, the wet spraying material of the present invention contains an alkali metal silicate and an alkali metal orthophosphate or an alkaline earth metal orthophosphate. Alkali metal silicates, alkali metal orthophosphates or alkaline earth metal orthophosphates are used alone in existing dry spraying materials and wet spraying materials, respectively. There is a feature. The effect of the present invention is not exerted even when an alkali metal silicate, an alkali metal orthophosphate or an alkaline earth metal orthophosphate is used alone.

The alkali metal silicate used in the present invention is specifically exemplified by sodium silicate No. 1 and potassium silicate. The additive amount of the alkali metal silicate is in the range of 0.3 to 4.0% by weight based on the total of 100% by weight of the refractory aggregate and the refractory ultrafine powder. Here, it is not preferable that the addition amount of the alkali metal silicate is less than 0.3% by weight because the adhesive strength is lowered, and if the addition amount exceeds 4.0% by weight, It is not preferable because the corrosion resistance is reduced.

When the alkali metal silicate is previously added to the refractory composition comprising the refractory aggregate and the refractory ultrafine powder and kneaded, a powder of the alkali metal silicate is added, and water is further added. It is also possible to knead the mixture, or to add and knead it using an aqueous solution of an alkali metal silicate and water. When the alkali metal silicate is added at the spray nozzle, an aqueous solution of the alkali metal silicate is used.

The alkali metal orthophosphate or alkaline earth metal orthophosphate (hereinafter referred to as "alkali metal orthophosphate") is preferably one having good reactivity with alkali metal silicate, but is particularly limited. Not something.
Specific examples of the alkali metal orthophosphate include sodium monophosphate and potassium potassium phosphate, and specific examples of the alkaline earth metal orthophosphate include calcium monophosphate and the like. . When the alkali metal orthophosphate or the like is previously added to the refractory composition comprising the refractory aggregate and the refractory ultrafine powder and kneaded, it is preferable to use the alkali metal orthophosphate as a powder, When the alkali metal orthophosphate is added by a spray nozzle, the concentration is 40 to 60% by weight, more preferably 45% by weight.
It is used as a 55% by weight aqueous solution.

The relationship between the concentration ratio of alkali silicate / alkali metal orthophosphate in an aqueous solution and the gelling property is 1
FIG. 1 shows an example of sodium silicate and sodium phosphate. FIG. 1 shows the relationship between the concentration of No. 1 sodium silicate, the concentration of first sodium phosphate and the gelation index in an aqueous solution in which No. 1 sodium silicate and sodium phosphate are mixed. Here, the gelation index, when gelling at room temperature, is an index of time until gelation, the longer the gelation time,
The gelation index takes a large value. When gelation does not occur at room temperature, the gelation index is derived taking into account the heating temperature until gelation and the time until gelation takes into account, and is a larger value than when gelation occurs at room temperature. The higher the gelation temperature and the longer the gelation time, the larger the gelation index. The concentration ratio of No. 1 sodium silicate and sodium phosphate monophosphate strongly influences the gelation index. In the region where the concentration ratio is close to 1, that is, when both are almost equal in amount added, gelation immediately occurs at normal temperature, The chemical conversion index shows a minimum value of 1. Regions where the concentration ratio is away from 1,
That is, when either one is large and the other is small, or 0.5 or less or 2.0 or more, the gel is not formed at normal temperature and a gel is generated by heating at 80 ° C. or more. At this time,
The gelation index takes a large value.

As described above, when the concentration ratio of alkali silicate / alkali metal orthophosphate is about 1, the gelation starts immediately at room temperature when the concentration ratio is approximately 1, and as the concentration ratio departs from 1, the gelation starts at room temperature. Gelation time is slow. In addition, the rate at which an aqueous solution changes to a gel is temperature dependent, with higher temperatures increasing the rate of gelation. From these facts, as the relationship between the temperature of the surface to be sprayed and the addition ratio, when the temperature of the surface to be sprayed is less than 105 ° C., the addition ratio of alkali silicate / alkali metal orthophosphate or the like is 0.5%. Beyond
Desirably, the temperature of the surface to be sprayed is 1
When the temperature is 05 ° C. or higher, the ratio of the alkali silicate / alkali metal orthophosphate is preferably 2.0 or more, or 0.5 or less.

That is, the method for applying the wet spray material of the present invention is as follows.
When the temperature of the surface to be sprayed is less than 105 ° C., the addition ratio of the alkali metal silicate / alkali metal orthophosphate or the alkaline earth metal orthophosphate exceeds 0.5 to 2.0%.
And the temperature of the surface to be sprayed is 105
When the temperature is not lower than ° C., the addition ratio of alkali metal silicate / alkali metal orthophosphate or alkaline earth metal orthophosphate is 0.5 or less, or 2.0 or more. .

The alkali silicate and the alkali metal orthophosphate can be added to the refractory composition or added as an aqueous solution using a spray nozzle.

Hereinafter, the method for applying the wet spray material of the present invention will be specifically described. As a first method, the refractory composition 1
The alkali silicate is added in an amount of 0.3 to 4.0% by weight with respect to 00% by weight, kneaded with water or other kneading liquid so as to be soft enough to be pumped, and transported to a spray nozzle.
In the spray nozzle, an aqueous solution of an alkali metal orthophosphate mixed with compressed air is added in an amount of 0.3 to 4.0% by weight as an alkali metal orthophosphate or the like, and is sprayed together with the kneaded material.

As a second method, the refractory composition 100
0.3 to 0.3% by weight of alkali metal orthophosphate
After adding 4.0% by weight, the mixture is kneaded with water or another kneading liquid so as to be soft enough to be pumped and pumped, and is transported to a spray nozzle. In the spray nozzle, 0.3 to 4.0% by weight of an alkali silicate aqueous solution mixed with compressed air is added as an alkali silicate and sprayed together with the kneaded material.

In the first and second methods, of the alkali silicate and the alkali metal orthophosphate, etc., the one with the larger addition amount is added to the refractory composition in advance, and the smaller one is added as an aqueous solution with a spray nozzle. Is preferred.

As a third method, the refractory composition 100
0.3 to 4.0% by weight of alkali silicate with respect to% by weight,
0.3 to 4.0% by weight of an alkali metal orthophosphate is added, adjusted to a softness enough to be pumped with water or other mixed liquid, kneaded, transported to a spray nozzle, and blown by compressed air. wear. This method is preferably applied to hot spraying. This method has an advantage that a pump for sending an aqueous solution is not required.

[0029]

The following examples further illustrate the wet spraying material of the present invention, but it should be understood that the present invention is not limited to these examples. EXAMPLES In Examples 1 to 12 of the present invention shown in Tables 1 and 2, a predetermined amount of sodium silicate 1 was added to 100% by weight of a refractory composition mainly composed of a chamotte and a fused alumina raw material whose particle size had been adjusted in advance.
And kneaded with a mixer at a water content of 14 to 15% by weight. For the kneaded material pumped to the spray nozzle,
Aqueous sodium phosphate aqueous solution (concentration: 50% by weight) was added together with the compressed air in an amount of 1 to 8% by weight, and the additive amount ratio of anhydrous sodium silicate / sodium primary phosphate (hereinafter referred to as S / P ratio) was set at 0.
13 to 8. The panel surface temperature immediately before spraying was measured at room temperature (about 20 ° C), 200 ° C, 40
The temperature was set to 0 ° C. and 600 ° C., and the kneaded material was sprayed with compressed air onto a panel about 1 m away from the nozzle.

The observation and measurement items in the spray test are as follows. The degree of dust generation was "Fine" when almost water vapor alone, "Notable" when the panel was cloudy and difficult to see due to dust from the spraying material, and "Low", "Medium" and "High" in the middle. . Peeling indicates a state away from the surface to be sprayed, "None" indicates no state at all, "Fine" indicates hardly confirmable, "Notable" indicates a total of about 1/2 or more of the spray area, intermediate Are "small", "medium" and "many". Adhesive strength is "low" by adjusting the force when peeling off the construction body after the test,
"Medium" and "High" were used. In addition, most of them fell off during spraying,
When it was not possible to determine the adhesive strength, it was judged as "falling off". The adhesion rate (α%) is calculated by the following formula: W1 is the weight of the material that has fallen without bonding after the test, and W2 is the adhesive material that has been peeled off.
α = W2 / (W1 + W2) × 100.

Next, each embodiment will be described. Examples 1 to 4 of the present invention in Table 1 show spraying conditions when the S / P ratio was changed to 8 to 3. Dust generation is "fine" of almost only steam at each temperature. Peeling was “absent” at 20 ° C., “significant to many” at 200 ° C., and “medium” at 400 ° C. and 600 ° C. Adhesive strength is low below 200 ° C,
At 0 ° C., each of the present invention products is high. Adhesion ratio: S / P ratio = 8-6
In the products 1 and 2 of the present invention, since they do not immediately cure at 200 ° C. or lower, they are as low as 43 to 44%,
When the temperature reaches 00 ° C., the content becomes 84 to 88%. The product 3 of the present invention having an S / P ratio of 4 was low at 20 ° C., but 85 to 200 ° C. or higher.
87%. In Example 4 where the S / P ratio = 3, the temperature increases from 45% to 78% from 20 ° C. to 400 ° C., but decreases to 67% at 600 ° C. The products 5 and 6 of the present invention in Table 1 and the products 7 and 8 of the present invention in Table 2 show spraying conditions when the S / P ratio was changed to 0.13 to 0.33. Dust generation is "fine" of almost only steam at each temperature. Peeling was “none” at 20 ° C., “many” at 200 ° C., and “medium” at 400 ° C. and 600 ° C. Adhesive strength is low below 200 ° C, but 40
At 0 ° C. and 600 ° C., each of the products of the present invention is high. Adhesion rate is S / P
In the present invention products 5 to 7 having a ratio of 0.13 to 0.25, the composition does not cure at room temperature, and is as low as 43 to 48%.
And becomes lower as the temperature becomes higher.
In the case of the product 8 of the present invention having an S / P ratio = 0.33, 6
It is 9%, but at other temperatures it is 50% or less.

The products 9 to 12 of the present invention in Table 2 have S / P ratios of 2
This is the spraying condition when the value is changed to 4.6. Dust generation is "fine" of almost only steam at each temperature. 3. S / P ratio
The product 12 of the present invention 6 and the product 11 of the present invention having an S / P ratio of 3.3
The curing time is slow and runs down at 20 ° C.
At ℃, adhesive strength is low and peeling is large. At 400 ° C,
Adhesion at the interface is observed, but runs off at a certain thickness or more. At 600 ° C., there is little peeling, the bonding strength is high, and the bonding ratio is 88 to 92%. S / P ratio 2.6
The product 10 of the present invention and the product 9 of the present invention having an S / P ratio of 2.0 have a relatively short curing time and a moderate adhesive strength, but are adhered even at 20 ° C. At 200 [deg.] C., the degree of adhesion is 77 to 88% with moderate peeling and adhesive strength. At 400 ° C., each factor is in the most balanced state, there is little peeling,
The bonding strength is high, and the bonding ratio is 94 to 96%. 600
When the temperature reaches ℃, the peeling is small and the bonding strength is high, but the bonding rate is slightly lowered to 76 to 82%.

[0033]

[Table 1]

[0034]

[Table 2]

Next, comparative products shown in Table 3 will be described. Comparative products 1 and 2 are wet spray materials when sodium silicate and sodium phosphate monobasic are used alone. Although dusting is hardly observed in any case, the adhesive strength is low, and the peeling is remarkably increased at 400 ° C. or higher for Comparative Product 1 and 200 ° C. or higher for Comparative Product 2. When the peeling is “absolute” to “low”, the adhesion ratio is 92 to 95%, and when the peeling is “significant”, most of the adhesive falls off from the majority during the test and becomes 55 to 10% or less. Comparative product 3
Is a silicate bond dry spray material, and Comparative Product 4 is a phosphate bond dry spray material. Dust generation and peeling increase as the temperature increases. In the comparative product 3, the adhesive strength gradually increases as the temperature increases, but the adhesive rate decreases moderately from 76% to 65%. In the comparative product 4, the adhesive strength gradually increased as the temperature increased, and the adhesive rate reached the maximum value of 82 at 200 ° C.
%, And slightly lower at room temperature or at 400 ° C. or higher.

[0036]

[Table 3]

Next, the surface temperature of the surface to be sprayed is raised from 20 ° C. to 4 ° C.
Up to 00 ° C., the product 9 of the present invention which has little peeling and a high adhesion
The apparent porosity after drying at 105 ° C. was measured for each of the products 11 and 12 of the present invention, which had little peeling at 10 and 600 ° C. and had a high adhesion rate, and for comparison, samples after the spray test at each temperature in Comparative Products 1 and 4. did. Table 4 shows the obtained results. There is no statistically significant difference between the four types of the present invention, and the apparent porosity slightly increases as the temperature of each of the present products increases. On the other hand, although the apparent porosity of the comparative product 1 is the smallest,
The difference from the product of the present invention was small. At 400 ° C. or higher, a sample that could be used for measurement could not be obtained. In the case of the comparative product 4, the apparent porosity was very large at any temperature, and it was found that a dense structure was not formed.

[0038]

[Table 4]

[0039]

According to the present invention, it is possible to provide a denser and more durable material than a dry spray material without requiring a construction frame or a curing time unlike a conventional casting method. The advantage of wet spraying, that is, the addition ratio is adjusted with the same binder, which is the greatest feature of the present invention, while maintaining a dense and uniform construction body with a high adhesion rate that hardly generates dust and rebound loss Just by doing, it became possible to work in a wide temperature range from normal temperature to warm and hot. As a result, there is no need to distinguish between a wet spraying method and a normal method, a warm method, and a hot method, and since there is no need for a construction frame or curing time, labor saving,
It has become possible to provide a refractory having high durability in a short time at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the concentration of sodium silicate No. 1, the concentration of sodium phosphate first and the gelation index in an aqueous solution in which sodium silicate 1 and sodium phosphate 1 are mixed.

Continuation of front page (72) Inventor Ichiro Hattori 2-1-1 Otemachi, Chiyoda-ku, Tokyo Shinagawa White Brick Co., Ltd. F-term (reference) 4G033 AA02 AA03 AA06 AA07 AA09 AA10 AA12 AA15 AA17 AA24 AB03 AB04 BA02 4K051 AB03 BE03 LA01 LA12

Claims (9)

[Claims] 1. 70 to 90% by weight of a refractory aggregate having a particle size exceeding 10 mm and not more than 10% by weight, and others having a particle size of 10 to 20 μm, and a particle size of 20 μm.
A refractory composition containing less than 10 to 30% by weight of a refractory ultrafine powder of less than 10% by weight of an alkali metal silicate and an alkali metal orthophosphate or an alkaline earth metal orthophosphate. Spraying material. 2. The addition amount of the alkali silicate and the alkali metal orthophosphate or the alkaline earth metal orthophosphate is 0.3 to 4.0, respectively, based on 100% by weight of the refractory composition.
The wet spray material according to claim 1, which is in the range of% by weight. 3. The group of refractory aggregates comprising chamotte, rholite, fused alumina, sintered alumina, bauxite, kyanite, andalusite, mullite, silica, spinel, magnesia, zircon, silicon carbide and graphite. And at least one selected from the group consisting of alumina, silica, mullite, titania, chromia, zirconia, silicon carbide, and carbon. The wet spray material according to claim 1 or 2. 4. The wet spray material according to claim 1, further comprising a curing modifier, a dispersant, a fiber and / or a metal. 5. The wet spray material according to claim 1, wherein the alkali metal silicate is sodium silicate 1 or potassium silicate. 6. The method of claim 1, wherein the alkali metal orthophosphate is sodium phosphate monobasic or potassium phosphate monobasic and the alkaline earth metal orthophosphate is calcium monophosphate.
The described wet spray material. 7. The method according to claim 1, wherein the temperature of the surface to be sprayed is 10 or more.
When the temperature is lower than 5 ° C., the ratio of the alkali metal silicate to the alkali metal orthophosphate or the alkaline earth metal orthophosphate is more than 0.5 and less than 2.0. Construction method. 8. The method for applying a wet spray material according to claim 1, wherein the temperature of the surface to be sprayed is 10 or more.
When the temperature is 5 ° C. or higher, the addition ratio of alkali metal silicate / alkali metal orthophosphate or alkaline earth metal orthophosphate is 0.5 or less, or 2.0 or more. Construction method. 9. Among the alkali metal silicate and the alkali metal orthophosphate or the alkaline earth metal orthophosphate, a larger amount is added to the wet spraying material, and a smaller amount is added as an aqueous solution by a nozzle. The method for applying a wet spray material according to claim 7.