TWI681941B - Dry spray material for hot room, and dry spray construction method for hot room - Google Patents

Abstract

The purpose of the present invention is to improve adhesion, adhesion, and corrosion resistance in a dry spray material for hot room and a dry spray construction method for hot room. In order to achieve this goal, the hot dry spray construction method of the present invention is to send a complex containing a refractory material and a binder toward a nozzle through a pipe, and add water to the front end of the nozzle to perform hot spray. , Based on the total mass of 100% by mass of the refractory material and the binder, containing bitter clay limestone with a particle size of 1 mm or more, 10% by mass or more and 50% by mass or less, the amount of the water added is relative to the refractory material and the binding agent The total amount of the agent is 100% by mass, and its added percentage is 10% by mass or more and 50% by mass or less.

Description

Dry spray material for hot room, and dry spray construction method for hot room

The invention relates to a dry-type spray material (amorphous refractory) for hot-room repair suitable for hot-room repair of industrial kilns such as a molten steel pan and a furnace body (furnace wall) of an electric furnace and a construction method thereof.

Amorphous refractory, according to its use and use different construction methods. For example, when an amorphous refractory is used as a castable material for the lining of an industrial kiln, the construction is performed through a kneading process of refractory materials and water, a casting process, a curing process, and a drying process.

On the other hand, there are also cases where amorphous refractory is used as an injection material for the construction or repair of industrial kilns. In this case, the construction methods are roughly divided into wet spray construction methods and dry spray construction methods. The wet spray construction method is to use a mechanical kneading mechanism such as a kneading machine to thoroughly knead the spray material and water in advance, and then send the kneaded product to the nozzle by the pump. The front end part introduces air and a quick-setting agent and sprays. The dry spray construction method does not use a mechanical kneading mechanism, but adds water to the dry powder spray material at the tip of the nozzle to spray.

In general, spray construction using spray materials can be carried out in either hot or cold environments, and dry spray construction methods are applicable in both environments. However, the wet spray construction method is generally not applicable in a hot room environment. This is because, in the case of the wet spray construction method, prior mixing operations are required, so after the construction will occur: cleaning operations such as the mixing machine, the cleaning operation of the transfer hose used when pumping with the pump, etc. . Therefore, the spray construction in the hot room environment is not suitable for the wet construction method, and most of the simple construction methods, that is, the dry spray construction method are used.

The spray materials used in this dry spray construction method (amorphous refractory for dry spray) must allow the spray material to be applied to the surface to be applied during spraying, the spray material and the surface of the sprayed industrial kiln after operation The adhesion of the construction surface and the corrosion resistance of the sprayed material are improved.

As an amorphous refractory for dry spraying, Patent Document 1 discloses a spray material containing bitter soil limestone. However, as a result of hot spraying construction using spray materials containing bitter soil limestone, the present inventors found that adhesion, adhesion, and corrosion resistance are still insufficient.

[Patent Document 1] Japanese Unexamined Patent Publication No. 58-145660

[Problems to be solved by the invention]

The problem to be solved by the present invention is to improve the adhesion, adhesion and corrosion resistance in the dry spray material for hot room and the dry spray construction method for hot room. [Technical means to solve the problem]

According to an aspect of the present invention, the following dry spray material for hot room is provided. "A dry spray material for hot rooms, containing refractory materials and binders, In the total amount of 100% by mass of the refractory and the binder, it contains bitter soil limestone with a particle size of 1 mm or more, 10% by mass or more and 50% by mass or less. To the total amount of 100% by mass of the refractory material and the binder, water is added in an amount of 10% by mass or more and 50% by mass or less in an outer percentage. "

According to another aspect of the present invention, the following hot dry spray construction method is provided. "A hot-air dry spray construction method, which is to send a complex containing a refractory material and a binder toward the nozzle through a pipe, add water to the front end of the nozzle to perform hot-air spray, The compound is contained in 100% by mass of the total amount of the refractory material and the binder, and contains 10% by mass or more and 50% by mass or less of bitter clay limestone having a particle diameter of 1 mm or more, The added amount of the water is 100% by mass relative to the total amount of the refractory and the binder, and the added percentage thereof is 10% by mass or more and 50% by mass or less. " [Effect of invention]

According to the present invention, by limiting the content of bitter limestone and water of 1 mm or more to a specific range, the adhesion, adhesion, and corrosion resistance can be improved. As an effect of improving the adhesion and adhesiveness, specifically, first, water is volatilized to generate open pores in the construction body of the spray material, and then, the bitter soil limestone with a particle diameter of 1 mm or more is decomposed to generate carbon dioxide, and the carbon dioxide is used to generate Open stomata. That is, the passage through the construction body is generated in two stages, thereby obtaining quick-drying. In this way, dehydration from the interface between the construction body (spraying material) and the work body can be promoted, and the adhesion and adhesion can be improved.

The dry spray material for hot room of the present invention contains 100% by mass of refractory materials and binders (hereinafter referred to as "total amount") and contains 10% by mass or more of 50% by mass of bitter soil limestone with a particle diameter of 1 mm or more Below, with respect to the total amount of 100% by mass, water of 10% by mass or more and 50% by mass or less is added as an additional percentage.

該分解反應，是從約600℃開始，在約800℃結束。因此，當將本發明的熱間用乾式噴射材進行熱間噴射施工，如前述般，首先讓水揮發而在噴射材的施工體產生開放氣孔，然後，讓粒徑1mm以上的苦土石灰石分解而產生二氧化碳，利用該二氧化碳來產生開放氣孔。結果，能讓密合性及接著性提高。又「熱間」是指，被施工面的溫度大致600℃以上的環境。Bitter limestone (CaCO ₃ •MgCO ₃ ) with a particle size of 1 mm or more generates carbon dioxide (CO ₂ ) by the decomposition reaction of the following formula (1).

The decomposition reaction starts at about 600°C and ends at about 800°C. Therefore, when the hot spraying method of the present invention is performed with a dry spray material, as described above, first of all, the water is volatilized to generate open pores in the spray material construction, and then, the bitter soil limestone with a particle size of 1 mm or more is decomposed Carbon dioxide is generated, and the carbon dioxide is used to generate open pores. As a result, adhesion and adhesion can be improved. "Hot room" refers to an environment where the temperature of the work surface is approximately 600°C or higher.

When the content of the bitter soil limestone with a particle size of 1 mm or more is less than 10% by mass, a sufficient effect of improving adhesion and adhesion cannot be obtained. On the other hand, when the content of bitter earth limestone with a particle size of 1 mm or more exceeds 50% by mass, the carbon dioxide generated by the decomposition reaction becomes excessive, which reduces the adhesion and adhesion. In addition, the use of carbon dioxide produces more pores, which reduces the corrosion resistance. The content of bitter soil limestone having a particle diameter of 1 mm or more is preferably 20% by mass or more and 40% by mass or less in a total amount of 100% by mass.

The dry spray material for hot room of the present invention may contain bitter limestone with a particle size of less than 1 mm. However, when a large amount of bitter soil limestone with a particle size of less than 1mm is contained, the decomposition reaction of the bitter soil limestone with a particle size of less than 1mm (formula (1) above) will occur immediately after being attached to the surface to be constructed. The hydration reaction of CaO (the following formula (2)) generated by the decomposition reaction causes Ca ^{2+ to be} eluted in the construction. In this way, the viscosity of the slurry-like construction will increase early, and the wettability of the surface to be constructed will not be ensured to be hardened, and there is a concern that the adhesion will be reduced. Therefore, the content of bitter soil limestone with a particle size of less than 1 mm is preferably 25% by mass or less (including 0) in the total amount of 100% by mass.

In the present invention, the amount of water added during spraying is as described above, and the added percentage is 10% by mass or more and 50% by mass or less with respect to the total amount of 100% by mass. When the amount of water added is less than 10% by mass, the spray material and water cannot be fully mixed, and spray construction cannot be performed. In addition, in the state of the hot room, because the amount of water is small, the water volatilizes immediately, and the heat is easily transferred to the construction body, which causes the decomposition reaction of the bitter soil limestone with a particle diameter of 1 mm or more to be excessively early, and the production of carbon dioxide is excessively early, which causes Compatibility and adhesion are reduced. On the other hand, when the amount of water added exceeds 50% by mass, the open pores generated by the volatilization of water and the open pores generated by the carbon dioxide generated from the bitter soil limestone with a particle diameter of 1 mm or more will cause excessive opening. Porosity reduces corrosion resistance. The amount of water added is preferably 20% by mass or more and 40% by mass or less relative to the total amount of 100% by mass.

The dry spray material for hot room of the present invention, as a refractory material other than bitter soil limestone, may contain various refractory materials generally used in the spray material, and considering its compatibility with bitter soil limestone, its main body is preferably Alkaline refractory materials (alkaline oxides) such as magnesium oxide, olivine (Olivine), used magnesium oxide, and carbon brick scraps. As a refractory material other than the alkaline refractory material, alumina or the like may be contained.

The binder can be used as a bonding material and generally used in dry spray materials. For example, silicates such as sodium silicate, phosphates, asphalt, powdered resin, and alumina cement can be cited. In addition, the usage amount (content) of the bonding material may be the same as that of a general dry spray material, and for example, it is 1% by mass or more and 10% by mass or less in a total amount of 100% by mass.

In addition, additives can also be used in the binder. As additives, various additives such as hardeners, dispersants, and thickeners can be used. For example, slaked lime can be used as a hardener, phosphate can be used as a dispersant, and clay can be used as a thickener.

The above-mentioned dry spray material for hot room of the present invention is suitable for the hot spray dry spray construction method. In this construction method, the complex containing the aforementioned refractory material and binder is pressure-fed toward the nozzle through a pipe. Water is added to the front end of the nozzle to perform inter-heat injection. [Example]

Table 1 and Table 2 show the material composition and evaluation results of the examples and comparative examples of the dry spray material for hot room of the present invention. In Table 1 and Table 2, the "others" of the binder are clay, slaked lime, dispersant, etc. The evaluation items and evaluation methods are as follows.

<Corrosion resistance> The dry spray material for hot room of each example was sprayed from the nozzle at a spray amount of 15 kg/min toward the surface of the magnesia brick heated to 1000°C as the surface to be worked for 1 minute. At this time, the amount of water added to the tip of the nozzle is set to the amount shown in each example of Table 1 and Table 2. That is, the "addition amount of water" shown in Table 1 and Table 2 is an addition amount that is an added percentage with respect to the total amount of 100% by mass. By performing spraying for 1 minute, a sprayed structure including a sprayed material structure having a thickness of approximately 50 mm was obtained. For a sample of a predetermined size cut out from the sprayed structure, a rotary erosion tester was used, with converter slag of C/S=3.5 as an erosion agent, and erosion was conducted at 1650 to 1700°C for 3 hours. The maximum erosion of each example was measured, and the relative amount when the maximum erosion of Example 1 was 100 was determined. The following three-level evaluation was performed, that is, the case where the relative amount was 100 or less was evaluated as ◎ (excellent), the case where it exceeded 100 and 110 or less was evaluated as ○ (good), and the case where it exceeded 110 was evaluated as × (impossible).

＜Adhesiveness＞ For the sprayed constructions of each example obtained according to the aforementioned method, the shear stress between the construction of the sprayed material and the magnesia brick was measured, and the relative value when the shearing stress of Example 1 was 100 was calculated, and the following 3 Grade evaluation, that is, the case where the relative value is 100 or more is evaluated as ◎ (excellent), the case where it exceeds 70 and less than 100 is evaluated as ○ (good), and the case where it is 70 or less is evaluated as × (impossible).

<adequacy> As shown in the upper part of FIG. 1, a 15 mm interval is set in the center of a magnesia-shaped magnesia brick (yolk-shaped brick), and after the cast compound is cast, cured, and dried, as shown in the lower part of FIG. 1, The test piece was obtained by sintering at 1400°C for 3 hours with a load of 0.25 MPa applied from the tip of the yolk-shaped brick. The kneaded material was added to the spray material of each example by adding water corresponding to the amount of water added and kneading. Made. For the test pieces of each example, the flexural strength of the adjoining surface was measured by a 3-point bending test to obtain the relative value when the flexural strength of Example 1 was 100, and the following three-level evaluation was performed, that is, the relative value A case of 100 or more was evaluated as ◎ (excellent), a case of more than 60 and less than 100 was evaluated as ○ (good), and a case of 60 or less was evaluated as × (impossible). The evaluation of the adhesion is an index indicating the strength of the adhesion between the injection material and the surface to be applied after the operation in the industrial kiln after injection in actual injection construction.

<Comprehensive evaluation> The following three-level evaluation was performed, that is, in the above-mentioned evaluations, ◎ 2 or more cases were evaluated as ◎ (excellent), ○ 2 or more cases were evaluated as ○ (good), and 1 of them was × Is evaluated as × (impossible) in the case of and the unmeasured case. This comprehensive evaluation is an index indicating the durability of the actual spray construction.

Examples 1 to 11 shown in Table 1 are dry spray materials for hot rooms within the scope of the present invention. The comprehensive evaluations were both ◎ (excellent) or ○ (good), and good results were obtained.

Comparative Example 1 in Table 2 is an example in which the content of bitter soil limestone with a particle size of 1 mm or more is small. The effect of improving adhesion and adhesion cannot be sufficiently obtained, and the evaluation of adhesion and adhesion is × (impossible). Comparative Example 2 is an example in which the content of bitter soil limestone with a particle size of 1 mm or more is large. Too much carbon dioxide reduces adhesion and adhesion, and corrosion resistance also decreases.

Comparative Example 3 is an example in which the amount of water added is small. Spray construction cannot be carried out and cannot be measured. Comparative Example 4 is an example in which the amount of water added is large. The open pores become too much and the corrosion resistance decreases.

Comparative example 5 is an example in which calcined dolomite is used instead of bitter limestone. Because calcined dolomite has strong digestibility, it becomes unmeasured. Comparative Example 6 is an example in which limestone is used instead of bitter soil limestone. Limestone (CaCO ₃ ) produces low-melting compounds and reduces corrosion resistance.

FIG. 1 is an explanatory diagram showing an evaluation method of adhesion.

Claims (4)

A dry spray material for hot room, which contains refractory material and binder, In the total amount of 100% by mass of the refractory and the binder, it contains bitter soil limestone with a particle size of 1 mm or more, 10% by mass or more and 50% by mass or less. To the total amount of 100% by mass of the refractory and the binder, 10% by mass or more and 50% by mass or less of water are added in addition to the percentage. The dry spray material for hot room according to claim 1, wherein, In the total mass of 100% by mass of the refractory material and the binder, the content of bitter soil limestone with a particle size of less than 1 mm is 25% by mass or less (including 0). The dry spray material for hot room according to claim 1 or 2, wherein, In the total amount of 100% by mass of the refractory and the binder, the content of the bitter soil limestone with a particle size of 1 mm or more is 20% by mass or more and 40% by mass or less, The added amount of the water is 20% by mass or more and 40% by mass or less with respect to the total amount of the refractory material and the binder, which is 100% by mass. A hot-air dry spray construction method, which is to send a complex containing a refractory material and a binder toward a nozzle through a pipe, add water to the front end of the nozzle, and spray in a hot space. The compound is contained in 100% by mass of the total amount of the refractory material and the binder, and contains 10% by mass or more and 50% by mass or less of bitter clay limestone having a particle diameter of 1 mm or more, The added amount of the water is 10% by mass or more and 50% by mass or less with respect to the total amount of the refractory and the binder being 100% by mass, and the added percentage.

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