KR101604259B1 - Powdery set-accelerating agent and method for spray application of monothilic refractory - Google Patents

Abstract

An object of the present invention is to improve the transportability of a rapid setting agent to be added to a refractory composition by air stream transportation at the time of injection molding of a monolithic refractory, and to improve the mixing property of the rapid setting agent and the refractory composition. The present invention relates to a refractory composition which is used at the time of spraying refractories and which is refractory composition is directed to a nozzle (13) through a pipe (17) And a second powder material as a refractory raw material, wherein the second powder material contains particles having a particle diameter exceeding 0.5 mm by 5 mass% or more and a particle diameter of 0.1 By mass or more and 30% by mass or more of particles having a particle diameter of at least 30 mm.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for spraying powdery metal particles,

The present invention relates to a method of spraying and spraying powdery quick-setting admixtures and amorphous refractories to be added to a refractory composition which is air-fed in a pipe at the time of spraying of a monolithic refractory.

A refractory is applied to the inner surface of the iron core in a molten metal vessel such as a ladle or a converter. The refractory is in an environment susceptible to breakdown by being subjected to melting loss due to the slag contained in the molten metal or by exposure to a thermal shock due to the entrance and exit of the molten metal. Therefore, when the refractory is broken, the irregular refractory is sprayed to repair the damaged part.

As a maintenance method of the damage-worn portion, there is known a construction method in which a required amount of construction water is added to a refractory composition constituting a monolithic refractory material, kneaded, air-jetted to a nozzle, , Patent Documents 1 and 2). Examples of the rapid setting used herein include calcium hydroxide, sodium aluminate, potassium aluminate, sodium silicate, potassium silicate, sodium phosphate and the like.

Patent Document 1: JP-A-2009-047317 Patent Document 2: Japanese Patent Application Laid-Open No. 2011-214762 Patent Document 3: Japanese Patent Application Laid-Open No. 2000-226268

In the above-described Patent Documents 1 and 2, the quick-setting agent is air-streamed in a pipe by an air compressor and is mixed with the refractory composition by a nozzle. At this time, since the rapid setting such as slaked lime is a fine powder of about 100 탆 or less, there is a problem that when the refractory composition is mixed with the refractory composition, the refractory composition is not well impregnated and the rapid setting and refractory composition are not sufficiently mixed.

In addition, since the quick-setting agent is fine, there is a tendency to be easily attached to the pipe. There is a problem that when the fine particles are adhered to the pipe, they deviate from the designed components as much as they are attached.

As to the problem that the rapid setting and the refractory composition are not sufficiently mixed, for example, in the case where the refractory composition is mixed with the refractory fine powder in the powder quick-setting admixture as shown in Patent Document 3, the refractory composition is uniformly mixed with the refractory composition Thereby stabilizing the spraying operation.

However, even in the method of Patent Document 3, the mixture ratio of the refractory composition and the powder quick-setting admixture is still insufficient and the adhesion rate is not improved in some cases. In the method of Patent Document 3, there is a problem that the suppression of adhesion of particulate matter in the piping is insufficient and the quick-setting agent is attached and closed in the piping.

A problem to be solved by the present invention is to improve the mixing property of the quick-setting and refractory composition when adding a rapid setting agent to the refractory composition by air stream transportation when spraying the irregular refractory material, and at the same time, .

In view of the above problems, the inventors of the present invention have found that the particle size of the refractory fine powder mixed in the powder quick-setting admixture has a large influence on the mixture of the refractory composition and the rapid setting agent and the adhesion in the pipe, By mixing at least 5 mass% of particles having a particle diameter of more than 0.5 mm and not less than 30 mass% of particles having a particle diameter of not less than 0.1 mm and not more than 5 mm, it is possible to improve the mixing property of the quick-setting and refractory composition, So that it is possible to prevent piping from adhering.

The gist of the present invention is as follows.

(1) The powder quick-setting admixture of the present invention is used at the time of spraying refractory material, and when the refractory composition is conveyed by air through a pipe toward the nozzle, it is added to the refractory composition by air stream transportation And a second powder material as a refractory raw material, wherein the second powder material has a particle diameter of not less than 5% by mass and a particle diameter of not less than 0.1 mm and not more than 5 By mass or more and 30% by mass or more.

(2) In the powdery quick-setting admixture of the present invention, it is preferable that in the above (1), the second powder material contains 10 mass% or more of particles having a particle diameter of 5 mm or less and more than 0.5 mm.

(3) In the powdery quick-setting admixture of the present invention, the ratio of the first powder material and the second powder material in the mass ratio of 1: 3 to 3: 1 in (1) or (2) It is preferable that the first powder material is contained in an amount of 25 to 75 mass% and the second powder material is contained in an amount of 75 to 25 mass% when the total amount of the second powder material is 100 mass%.

(4) In the powder quick-setting admixture of the present invention, the first powder material may be selected from the group consisting of calcium hydroxide, aluminate, silicate, magnesium hydroxide, Portland cement, , Calcium chloride, calcium oxide, calcium hydroxide, and sodium phosphate.

(5) In the powdery quick-setting admixture of the present invention, the second powder material may be any of alumina, silica, alumina-silica, alumina-spinel, alumina-magnesia Wherein the carbonaceous material is selected from the group consisting of silica, alumina, silica, alumina, silica, alumina, silicon carbide, alumina-silicon carbide-kaolin, magnesia, magnesia- It is preferably one or two or more refractory materials selected from the group consisting of mica, chromia-magnesia, magnesia-lime and magnesia-alumina.

(6) Another aspect of the present invention is a spraying method for spraying a monolithic refractory using the powder quick-setting admixture according to any one of (1) to (5) Or the powdery acetic anhydride is added into the piping in front of the nozzle by airflow conveyance.

According to the powdery powders of the present invention, since the second powder material contains 5 mass% or more of particles having a particle diameter exceeding 0.5 mm and 30 mass% or more of particles having a particle diameter of 0.1 mm or more, And as a result, it is possible to improve the mixing property of the powder quick-setting admixture and the refractory composition.

In addition, even when the first powder material is adhered to the piping, the first powder material having particle diameters larger than that of the first powder material and having a particle diameter of 0.1 mm or more exerts the effect of removing the first powder material adhered to the piping. Particularly, the effect is great in particles having a particle size exceeding 0.5 mm. This can prevent the first powder material from sticking into the piping.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing an example of a spraying and construction apparatus of a monolithic refractory to which powder quick-setting admixture of the present invention is applied.
2 is a graph showing the relationship between the deposition rate of the spraying material on the sprayed surface and the apparent porosity of the sprayed sprayed material.

First, the spraying work of the monolithic refractory to which the powder quick-setting admixture of the present invention is applied will be described.

1 is a schematic view showing an example of a spraying and setting apparatus for a monolithic refractory. The spraying apparatus 1 shown in Fig. 1 is an apparatus for injecting and spraying a monolithic refractory material on the inner wall surface of a ladle, a converter, etc., and is equipped with an airflow type material conveying means 11, a material kneading means 12, (13) and a quick-dispensing supply means (14), and each means is connected via piping (15), (16), (17), and (18).

The air flow type raw material conveying means 11 conveys the refractory composition constituting the monolithic refractory by an air stream with an air compressor or the like. The refractory composition is supplied from the tank, and the refractory composition is discharged from the pipe 15 by using the air stream by the air compressor, and the material is kneaded Is conveyed to the means (12). It is preferable that the flow rate in the pipe 15 is 10 (m / s) to 30 (m / s) in the range of 30 mm or more and 50 mm or less in the inside diameter of the pipe 15.

A pipe 16 is connected to the upstream side of the connection portion of the pipe 15 with the material kneading means 12 and an air compressor is connected to the upstream side of the pipe 16 although not shown. In the piping 16, mist-like water is fed using the air stream of the air compressor, and mist-like water is added to the refractory composition in the pipe 15 from the piping 16. That is, the air compressor and the pipe 16 function as means for adding water.

The material kneading means 12 stirs and kneads the material to which the water is added via the pipe 16 to the refractory composition carried by the air flow type material conveying means 11 and the nozzle 13 is kneaded by the material kneading means 12 The kneaded material is sprayed onto the construction surface. The kneaded material is discharged from the nozzle 13 by airflow in a pipe 17 having a length of 5 m to 20 m from the outlet of the material kneading means 12, for example.

The quick-setting dispensing means 14 conveys the powder quick-setting admixture to the air compressor or the like by an air current. Powdery quick-setting is air-fed through the pipe 18 and added to the refractory composition (kneaded material) in the nozzle 13 at the nozzle 13. The addition amount of the powdery quick-setting agent is about 0.5 to 10% by mass relative to 100% by mass of the refractory composition. It is preferable that the flow velocity in the pipe 18 in the range of 10 mm or more and 20 mm or less of the inside diameter of the pipe 18 is 10 (m / s) or more and 40 (m / s) or less.

The refractory composition used in the spraying and coating apparatus 1 is not particularly limited as far as it is a material of the main refractory material, and examples of the refractory composition include alumina, silica, alumina-silica, alumina-spinel, alumina-magnesia, The present invention relates to an alumina-silicon carbide-based alumina-silicon carbide-based composite oxide having an intrinsic nature, alumina-silicon carbide, alumina-silicon carbide-kaolin, magnesia, magnesia-kaonite, kaolin, silicon carbide, silicon nitride, zirconia, -Magnesia quality, magnesia-lime quality, magnesia-alumina quality and combinations thereof can be used without any problem. Normally, a material having a mineral composition similar to the refractory to be sprayed may be selected.

Next, the powder quick-setting admixture of the present invention added to the refractory composition will be described.

The powder quick-setting admixture of the present invention comprises a first powder material which hardens the refractory composition and a second powder material which is a refractory material having fire resistance.

In addition, the powdery quick-setting agent of the present invention needs to be dry powder. This is because when the water is added to the powder quick-setting admixture, the strength of the applied product is lowered.

Examples of the first powder material include calcium hydroxide, sodium aluminate (sodium aluminate, potassium aluminate, calcium aluminate), silicates (sodium silicate, potassium silicate), magnesium hydroxide, Portland cement, sulfuric acid alum, calcium carbonate, calcium chloride, calcium oxide, Calcium hydroxide, sodium phosphate or the like, or a combination thereof. It is preferable that the first powder material has a particle size of 0.075 mm or less in most cases.

The material of the second powder material is not particularly limited as long as it is a refractory raw material, and the same material as the above-described refractory composition can be used without any problem. For example, the second powder material may include alumina, silica, alumina-siliceous, alumina-spinel, alumina-magnesia, alumina-kaonite, alumina-silicon carbide, alumina-silicon carbide- A refractory material of each of magnesia-kaonite, kaonite, silicon carbide, silicon nitride, zirconium, chalcia, dromite, chromia, chrome-magnesia, magnesia-lime and magnesia- , And a refractory material which is a combination of these.

Hereinafter, the first powder material is referred to as slaked lime and the second powder material is referred to as alumina.

In the present invention, alumina contains not less than 5 mass% of particles having a particle diameter exceeding 0.5 mm and not less than 30 mass% of particles having a particle diameter of not less than 0.1 mm and not more than 5 mm.

Thus, the powder quick-setting admixture according to the present invention has characteristics that it is easy to get into the refractory composition as compared with the powder quick-setting admixture containing alumina-free powder extrudate or alumina but not satisfying the above conditions. This property is attributed to the presence of a predetermined amount or more of particles of 0.1 mm or more contained in alumina. One of the specific reasons is that the grain size of 0.1 mm or more contained in alumina is larger than that of most of the slaked lime. Furthermore, alumina has a larger weight than slaked lime. Therefore, the particles of 0.1 mm or more contained in the alumina at a predetermined amount or more have higher kinetic energy than the calcium hydroxide. Therefore, the particles of 0.1 mm or more contained in alumina are more likely to be embedded in the refractory composition than the slaked lime. Further, since the particles exceeding 0.5 mm are present in a predetermined amount or more, the kinetic energy of the entire quick-setting agent is further increased, and the particles are likely to be embedded in the refractory composition. In addition, the slaked lime has the property that it is easy to dig into the irregular part of the alumina because most of the particles are less than 0.075 mm in the differential area. Therefore, the slaked lime has a property of being impregnated into the refractory composition together with particles of 0.1 mm or more of alumina.

That is, the powdery quick-setting admixture according to the present invention has characteristics that it is likely to be stuck in the refractory composition as compared with the powdery quick-setting admixture containing no alumina. Thereby exhibiting an effect of improving the mixing property of the powdery quick-setting agent and the refractory composition.

In addition, the particles of 0.1 mm or more contained in alumina exhibit an effect of removing the slaked lime attached to the piping because the particle diameter is larger than that of the slaked lime of the differential region. Therefore, alumina needs to contain particles of 0.1 mm or more. Furthermore, when particles exceeding 0.5 mm are transported by air current in a piping, the kinetic energy is large when the rapid setting agent is transported, so that particles having a diameter exceeding 0.5 mm are present in a predetermined amount or more, so that piping adhesion can be prevented very effectively.

If the content of particles of 0.1 mm or more and 5 mm or less in alumina is less than 30 mass% or less than 5 mass%, the above-mentioned effects can not be sufficiently obtained. The alumina preferably contains coarse particles in order to remarkably exert the above-mentioned effect of splitting and peeling. Specifically, the alumina preferably contains at least 10 mass% or more of particles exceeding 0.5 mm in particle diameter with respect to 100 mass% .

The upper limit of the particle size of the coarse particles in alumina is preferably 5 mm. The upper limit of the particle diameter of the coarse particles in alumina is limited by the diameter of the pipe 18. Here, the diameter of the pipe 18 is preferably about 10 mm or more and 20 mm or less. If the diameter of the pipe 18 is less than 10 mm, the diameter of the pipe 18 is small, so that the powder quick-setting admixture tends to be clogged. When the diameter of the pipe 18 exceeds 20 mm, it is necessary to increase the flow rate of the airflow (air flow rate) for airflow control of the particle accelerator accompanying the increase of the diameter. When the air flow rate is increased, there is a problem that the air blows out the sprayed material on the surface to be sprayed, thereby deteriorating the adhesion of the sprayed material. Therefore, the diameter of the pipe 18 is preferably 10 mm or more and 20 mm or less. When the diameter of the pipe 18 is 10 mm, when the particle diameter of the alumina exceeds 5 mm, the alumina tends to be occluded by the pipe 18. Therefore, the particle size of alumina is preferably 5 mm or less.

In addition, even when alumina having a particle diameter exceeding 5 mm is contained, if the content of the powder exceeding 5 mm in the rapid setting of the powder is less than 30 mass%, the alumina is less likely to be clogged and is practically usable.

There is no upper limit to the content of the coarse particles in the alumina exceeding the grain size of 0.1 mm or more or the grain size of 0.5 mm, and the alumina may be all coarse particles having a grain size of 0.1 mm or more or a grain size exceeding 0.5 mm. Even if alumina does not contain fine particles, fine particles are usually contained in the refractory composition, and the added amount of alumina is very small with respect to the refractory composition, so that the quality of the sprayed product is not adversely affected.

In the powder quick-setting admixture of the present invention, the blending ratio of the slaked lime and alumina is 1: 3 to 3: 1 in mass ratio, in other words, when the sum of the slaked lime and alumina is 100 mass%, the slaked lime is 25 to 75 mass% By mass to 25% by mass. If the content of the slaked lime is less than 25 mass%, the component to cure the refractory composition is insufficient, so that the adhesion rate to the construction surface tends to decrease. On the other hand, if the content ratio of alumina is less than 25% by mass, the air flowability may deteriorate and the powder metallurgy may adhere to the piping in the piping to occlude the piping.

Furthermore, in the case where the powder quick-setting admixture composed of only the first powder material such as slaked lime is kept in the storage tank for storage or is stored in the quick-dis- charge supply means 14 in Fig. 1 at the time of construction, The powder quick-setting admixture is solidified and the air stream can not be conveyed. Therefore, the powder can not be stored and maintained for only about several hours to one day. However, when the powder quick-setting admixture of the present invention is used, It is possible to preserve and maintain the state in which the powder quick-setting admixture is not solidified and the air current can be conveyed for a long period of time even if the first powder material is prevented from being cured and kept for more than one week continuously.

<Examples>

A construction test was conducted by the spraying apparatus of Fig. In the test, alumina raw materials whose particle size was adjusted as a refractory composition were used and various powders of rapid setting agents shown in Table 1 were added. The addition amount of the powder quick-setting admixture was set to 3% by mass relative to 100% by mass of the refractory composition.

As the powder quick-setting admixture, slaked lime and alumina having a particle diameter of 0.075 mm or less were used as the first powder material, and molten alumina having a predetermined particle size distribution as shown in Table 1 was used as the second powder material.

For the evaluation of the test, the degree of occlusion and adhesion rate in the piping was evaluated. It has a property that the deposition rate is improved when the mixing property of the powdery quick-setting agent and the refractory composition is improved. Therefore, the adhesion rate was also evaluated as an evaluation item. Specifically, the evaluation of the degree of occlusion in the piping was evaluated by the clogging rate due to powder quick-setting of the cross section of the pipe 18 in Fig. 1 in which the powdery quick-setting agent was air-fed. ∘ is the occlusion rate 0%, △ is the occlusion rate 10% or less, and X is the occlusion rate 100%. The adherence rate was evaluated as &quot; adhesion ratio (%) = weight of the applied body adhering to the construction surface / (weight of injection raw material (unshaped refractory) discharged from the nozzle) x 100 &quot;.

A construction temperature of 900 占 폚 and a construction flow rate (output flow rate of an air compressor not shown connected to the air flow type material conveyance means 11 through a conveyance path) of 4 to 5 (m ³ / min), the conveying speed of the refractory composition was 20 (m / s), and the feeding speed of the powder quick-setting admixture was 25 (m / s).

2 is a graph showing the relationship between the deposition rate and the apparent porosity of a spray-applied body obtained by varying the particle size distribution of fused alumina by setting the mass ratio of the slaked powder and the fused alumina to 1: 1 by using the spraying apparatus of FIG. / RTI &gt; From FIG. 2, it can be seen that when the deposition rate is 80% or more, the apparent porosity is stabilized at a low level, and a good applied body can be obtained. In the comprehensive evaluation, (1) the degree of occlusion in the pipe was rated as?, The rate of adhesion was 80% or more as?, (2) the degree of occlusion in the pipe was? Or? X or less, and the adhesion rate is 75% or less.

As shown in Table 1, in all of Examples 1 to 6, Examples 8 to 10 and Examples 14 and 15, the overall evaluation was ◎ and good results were obtained.

In Example 7, the overall evaluation was &amp; cir &amp; In Example 7, it is presumed that the proportion of slaked lime accounts for 20% by mass or less of the sum of the slaked lime and the molten alumina, so that the adhesion rate is slightly decreased due to insufficient components for hardening the refractory composition. However, Example 7 is superior to Comparative Example described later in the comprehensive evaluation, and therefore, it is a practically usable level except for a severe environment.

In Examples 11, 12, and 13, the overall evaluation was &amp; cir &amp; It is presumed that Examples 11, 12, and 13 have increased tendency to be occluded in the pipe 18 from those containing more than 5 mm of the fused alumina. However, in Examples 11, 12 and 13, the overall evaluation was &amp; cir &amp;

In any of Comparative Examples 1 to 3, the proportion of particles having a particle diameter of 0.1 mm or more and 5 mm or less in the fused alumina was less than 30% by mass, the evaluation of the pipe plugging property was lowered, and the adhesion rate also decreased. In Comparative Example 3, it is estimated that the ratio of the total amount of the alumina to the total amount of the slaked lime and the fused alumina was as low as 20 mass%, which is considered to be the cause of the evaluation of the pipe plugging property and the decrease in the adhesion rate.

In Comparative Example 4, the proportion of the particles exceeding 0.5 mm in diameter to the fused alumina is less than 5 mass%. Therefore, the evaluation of the pipe clogging property was deteriorated and the adhesion rate also decreased.

Comparative Example 5 is an example in which only calcium hydroxide is contained in the powder quick-setting admixture. In this case, the powder quick-setting admixture is hard to be poured into the refractory composition, so that the powder quick-setting admixture and the refractory composition are not sufficiently mixed, and thus the evaluation of the pipe clogging property and the adhesion rate are decreased.

From the above, it is important that the second powder material contains 5 mass% or more of particles having a particle diameter exceeding 0.5 mm and 30 mass% or more of particles having a particle diameter of 0.1 mm or more. The second powder material preferably has a particle diameter of 5 mm or less and contains particles of more than 0.5 mm in an amount of 10 mass% or more.

In addition, in the example, the powder quick-setting supply was maintained and maintained for more than one week in the quick-disinfecting and feeding means 14 shown in Fig. 1, but the powder quick-setting was not solidified,

&Lt; Industrial applicability >

The powder quick-setting admixture of the present invention can be used as a powder feedstock to be used as a feedstock in a variety of fields such as a converter, a ladle, a blast furnace, a barrel, a mixed iron car, an electric furnace, a secondary refining furnace, a tundish, It can be widely used for injection molding of irregular refractories to be used for lining repair or initial lining of molten metal containers such as incinerators, cement plants, cracks, heating furnaces, and the like. The powder quick-setting admixture of the present invention can be used for both hot and cold application.

1 spraying device
11 air flow type material conveying means
12 Material Mixing Means
13 nozzle
14 Level Payment Means
15, 16, 17, 18 piping

Claims (6)

A powdery quick-setting admixture which is used at the time of spraying refractories and added to the refractory composition by airflow in front of the nozzle or nozzle when the refractory composition is conveyed in an air stream by directing the refractory composition through a pipe,
A first powder material for curing the refractory composition,
And a second powder material which is a refractory raw material,
Wherein the second powder material contains 5 mass% or more of particles having a particle diameter exceeding 0.5 mm and 30 mass% or more of particles having a particle diameter of 0.1 mm or more. The powdery quick-setting material according to claim 1, wherein the second powder material has a particle diameter of 5 mm or less and contains particles of more than 0.5 mm at 10 mass% or more. The powder quick-setting admixture according to claim 1 or 2, wherein the first powder material and the second powder material are contained in a mass ratio of 1: 3 to 3: 1. The method of claim 1 or 2, wherein the first powder material is selected from the group consisting of calcium hydroxide, aluminate, silicate, magnesium hydroxide, Portland cement, alumina sulfate, calcium carbonate, calcium chloride, calcium oxide, calcium hydroxide, Or two or more kinds of powders. The method of claim 1 or 2, wherein the second powder material is selected from the group consisting of alumina, silica, alumina-silica, alumina-spinel, alumina-magnesia, alumina- -Carbene, zirconia, zirconia, zirconia, dolomite, chromia, chromia-magnesia, magnesia-lime and magnesia-alumina Wherein the refractory material is one or more refractory materials selected from the group consisting of a refractory material and a refractory material. A method for spraying and spraying a monolithic refractory using the powder quick-setting admixture according to claim 1 or 2, comprising the steps of: spraying the refractory composition, which is airflown through a pipe and discharged from a nozzle, into the piping in the nozzle or in front of the nozzle By weight based on the weight of the refractory material.

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