JP7441103B2 - Spraying material - Google Patents

Description

The present invention relates to a spraying material used for forming or repairing linings of molten metal containers such as pig iron mixers, hot metal ladle, molten steel ladle, etc., high temperature furnaces, molten metal processing equipment, etc.

BACKGROUND ART Spraying is performed as a means of forming or repairing the lining of molten metal containers, high-temperature furnaces, molten metal processing equipment, and the like. Spraying construction is broadly divided into wet spraying construction and dry spraying construction. Wet spraying is a construction method in which a spraying material that has been prepared in advance into a slurry by adding construction water is sprayed with a quick-setting agent added inside a nozzle or a pressure pipe. On the other hand, dry spraying is a construction method in which the spraying material is conveyed with gas in a dry state, and construction water is added at the nozzle section before spraying.

The construction body formed by such spraying construction has a problem in that it tends to peel off due to sintering shrinkage when it is heated by molten metal heat or the like.
Conventionally, as a technique for suppressing peeling of a construction body due to sintering shrinkage, a technique is known in which residual expansivity is imparted to a sprayed material (construction body) by using Rouseki raw material (for example, Patent Document 1) .

Although the use of the Rouseki raw material reduces peeling of the constructed body, the present situation is that peeling of the constructed body still occurs.

Japanese Patent Application Publication No. 2001-114573

The problem to be solved by the present invention is to provide a technique for suppressing peeling of a construction body formed by spraying construction.

The present inventors conducted many spraying tests of spraying material containing Rouseki raw material and investigated in detail the peeling phenomenon of the constructed body. The residual expansion on the back side (low temperature side) of the construction body is small compared to It was found that the difference in expansion facilitated the peeling of the construction body. In other words, the Rouseki raw material exhibits large residual expansion in the temperature range on the operating side of the construction body (for example, a high temperature range of about 1450°C), but it shows a large residual expansion property in the temperature range on the back side of the construction body (for example, a low temperature range of about 1200 °C). It does not show much residual expansion. For this reason, if only the Rouseki raw material is used, there will be insufficient residual expansion on the back side (low temperature side) of the construction body, resulting in residual expansion between the working side (high temperature side) and the back side (low temperature side) of the construction body. The expansion difference increases. If the residual expansion difference is large, cracks are likely to occur in the construction body, particularly when the construction body is cooled after use, and the construction body is likely to peel off.

Therefore, the present inventors provided sufficient and appropriate residual expansion even on the back side (low temperature side) of the construction body, and the residual expansion between the working side (high temperature side) and the back side (low temperature side) of the construction body. Aiming to reduce the difference, we investigated the raw material composition of suitable spray materials for this purpose. As a result, by using a combination of specific amounts of Rouseki raw materials and sillimanite group raw materials with an average particle size of more than 1 mm, we found that both the working side (high temperature side) and the back side (low temperature side) of the construction body were sufficiently The present inventors have discovered that it is possible to ensure a good residual expansion property and to reduce the difference in residual expansion, and have completed the present invention.

That is, according to one aspect of the present invention, the following spray material is provided.
A spraying material containing a refractory raw material and a binder, which contains 1% by mass or more and 15% by mass or less of a Rouseki raw material with an average particle size of more than 1 mm in 100% by mass of the refractory raw material and binder, and a sillimanite group raw material. 1% by mass or more and 40% by mass or less, and further contains a total of 50% by mass or more and 90% by mass or less of one or more selected from mullite raw material, chamotte raw material, bauxite raw material, silicon carbide raw material, alumina raw material, and silica raw material. , spray material.

According to the spray material of the present invention, peeling of a construction body formed by spray construction can be suppressed.

An image diagram of an example of wet spraying construction.

The spraying material of the present invention contains a refractory raw material and a binder, and contains 1% by mass or more and 15% by mass or less of a Rouseki raw material with an average particle size of more than 1 mm in 100% by mass of the refractory raw material and binder, and contains a sillimanite group Contains 1% by mass or more and 40% by mass or less of raw materials.

Rouseki raw material is a natural raw material whose main components are pyrophyllite, quartz, etc. When heated, quartz undergoes volumetric expansion due to transformation from α-type to β-type, imparting residual expandability to the sprayed material. More specifically, as described above, the Rouseki raw material exhibits large residual expansion in the temperature range on the operating surface side of the construction body (for example, a high temperature range of about 1450° C.).
In order to fully exhibit the effect of the residual expandability of the Rouseki raw material, the particle size of the Rouseki raw material is set to an average particle size of more than 1 mm. Here, the average particle size of more than 1 mm means that when the Rouseki raw material is sieved and separated through a sieve with an opening of 1 mm, the mass of the Rouseki raw material remaining on the sieve exceeds the mass of the Rouseki raw material that has passed through the sieve. It refers to particle size.

In the present invention, in order to ensure sufficient and appropriate residual expansibility on the working surface side (high temperature side) of the construction body, a Rouseki raw material with an average particle size of more than 1 mm is used in an amount of 1% by mass or more and 15% by mass or less.
If the amount of Rouseki raw material with an average particle size of more than 1 mm is less than 1% by mass, shrinkage cracks will occur in the construction body due to insufficient residual expansion on the operating surface side (high temperature side) of the construction body, making the construction body easy to peel off. If the amount of Rouseki raw material with an average particle size of more than 1 mm exceeds 15% by mass, the refractoriness will decrease. Further, the residual expansion on the operating surface side (high temperature side) of the construction object becomes too large, making the construction object easy to peel off.
The amount (content) of the Rouseki raw material having an average particle size of more than 1 mm is preferably 3% by mass or more and 8% by mass or less in 100% by mass of the total amount of the refractory raw material and the binder.

Sillimanite group raw materials exhibit gradual residual expansion from low temperature to high temperature ranges. Therefore, in the present invention, in order to ensure sufficient and appropriate residual expandability on the back side (low temperature side) of the construction body, the sillimanite group raw material is used in an amount of 1% by mass or more and 40% by mass or less.
If the content of the sillimanite group raw material is less than 1% by mass, shrinkage cracks will occur in the construction body due to insufficient residual expansion on the back side (low temperature side) of the construction body, and the construction body will easily peel off. If the content of the sillimanite group raw material exceeds 40% by mass, the residual expansion on the back side (low temperature side) of the construction object becomes too large, making the construction object easy to peel off.
The usage amount (content) of the sillimanite group raw material is preferably 5% by mass or more and 20% by mass or less based on 100% by mass of the total amount of the refractory raw material and the binder.
There are three types of sillimanite group raw materials: andalusite raw material, kyanite raw material, and sillimanite raw material, and from the viewpoint of expansion behavior, andalusite raw material or sillimanite raw material is preferable, and andalusite raw material is most preferable.

In this way, in the present invention, by using a combination of specific amounts of Rouseki raw materials and sillimanite group raw materials with an average particle size of more than 1 mm, both the working side (high temperature side) and the back side (low temperature side) of the construction body are heated. It is possible to ensure sufficient and appropriate residual expansibility in the process, and it is possible to suppress peeling of the construction body.
In other words, when only Rouseki raw material with an average particle size of more than 1 mm is used, residual expansion on the back side (low temperature side) of the construction body is insufficient, and as a result, the working side (high temperature side) and back side (low temperature side) of the construction body are insufficient. The difference in residual expansion between the two sides increases. If the residual expansion difference is large, cracks are likely to occur in the construction body, particularly when the construction body is cooled after use, and the construction body is likely to peel off. Furthermore, when only the sillimanite group raw material is used, sufficient residual expansion cannot be obtained on the operating surface side (high temperature side) of the construction body, and as a result, the construction body is likely to peel off.

The spraying material of the present invention includes 1% to 15% by mass of Rouseki raw materials with an average particle size of more than 1 mm and 1% to 40% by mass of sillimanite group raw materials in 100% by mass of the refractory raw materials and binder. However, the remainder includes at least one type selected from alumina-siliceous raw materials other than Rouseki raw materials and sillimanite group raw materials (for example, mullite raw materials, chamotte raw materials, bauxite raw materials, etc.), silicon carbide raw materials, alumina raw materials, and silica raw materials. It can contain 50% by mass or more and 90% by mass or less in total.
In addition, in the spray material of the present invention, the particle size of the refractory raw material is coarse, medium, coarse, medium, Adjust to fine grain.

In the sprayed material of the present invention, the total amount of refractory raw materials with a particle size of 1 mm or more is 100% by mass, and within this 100% by mass, the Al ₂ O ₃ content is less than 90% by mass and mullite is used as a mineral. It is preferable that the content of the refractory raw material is 50% by mass or more. Examples of refractory raw materials with an Al ₂ O ₃ content of less than 90% by mass and containing mullite as a mineral (hereinafter referred to as "mullite-based raw materials") include mullite, chamotte, bauxite, etc.; Since it does not substantially contain corundum, it has a characteristic of having a low coefficient of thermal expansion in the temperature range on the operating surface side of the construction body (for example, a high temperature range of about 1450° C.). Therefore, by including 50% by mass or more of mullite-based raw materials in 100% by mass of refractory raw materials with a particle size of 1 mm or more, construction can be carried out in the temperature range of the operating surface side of the construction body (for example, a high temperature range of about 1450°C). Thermal expansion of the body can be suppressed. Thereby, the stress generated due to thermal expansion of the sprayed material under high temperature can be reduced, and peeling of the construction body can be further suppressed. Note that the upper limit of the content of the mullite-based raw material in the total amount of 100 mass% of the refractory raw materials having a particle size of 1 mm or more is not particularly limited, but may be, for example, about 85 mass%.

In addition, the particle size as used in the present invention refers to the size of the sieve mesh when the refractory raw material is sieved and separated, and for example, the refractory raw material with a particle size of 1 mm or more refers to the size of the sieve mesh with a sieve mesh of 1 mm. A refractory raw material with a particle size of less than 1 mm is a refractory raw material that does not pass through a sieve with a sieve mesh size of 1 mm.

As the binder in the spray material of the present invention, binders commonly used for spray materials such as alumina cement, hydraulic transition alumina, Portland cement, magnesia cement, silicates, and phosphates can be used. It is. Further, part or all of the binder may be one that forms a cohesive joint by combining fine magnesia powder with a particle size of 75 μm or less and ultrafine silica powder. Among the above-mentioned binders, it is preferable to use alumina cement because it has high early strength and excellent corrosion resistance.
The amount (content) of the binder to be used can be approximately 1% by mass or more and 15% by mass or less based on 100% by mass of the total amount of the refractory raw material and binder.

In addition to the above-mentioned refractory raw materials and binders, various additives such as dispersants, hardening modifiers, fibers, and thickeners can be used in the spray material of the present invention. In addition, in the present invention, these additives shall be added in an amount added to 100% by mass of the total amount of the refractory raw material and the binder, and the amount to be added shall also take into account common general knowledge within the range that does not impair the effects of the present invention. The decision shall be made accordingly.

The spraying material of the present invention can be widely applied to forming and repairing linings of molten metal containers such as pig iron cars, hot metal ladle, molten steel ladle, etc., high temperature furnaces, molten metal processing equipment, etc. It can be suitably applied to hot metal ladle. The spraying material of the present invention contains a raw material of Rouseki, and since the temperature of hot metal is lower than that of molten steel, the raw material of Rouseki softens and becomes semi-molten, deforming greatly under load and causing cracks in the construction body during the cooling stage. It is unlikely to cause any harmful effects such as Furthermore, since hot metal has a lower viscosity than molten steel, it can easily be inserted into cracks, so it is preferable to use a spray material that does not easily cause cracks, such as the one of the present invention, in a pig iron mixing car or a hot metal ladle.

The spray material of the present invention can be suitably used for wet spray construction between wet spray construction and dry spray construction. Wet spraying makes it easier to obtain a dense construction compared to dry spraying, and it is possible to ensure sufficient and appropriate residual expansion on both the operating side (high temperature side) and back side (low temperature side) of the construction. The effects of the invention can be significantly obtained.

Further, in the spray material of the present invention, the contents of the Rouseki raw material and the Sillimanite group raw material can be adjusted as appropriate depending on the construction conditions. For example, when used in wet spraying construction, the contents of the Rouseki raw material and the sillimanite group raw material can be reduced because a dense construction body is easily obtained as described above. That is, in a dense construction body, the above effects are likely to be obtained even if the Rouseki raw material and the Sillimanite group raw material are used in small amounts. On the other hand, even in wet spraying construction, when using it as a hot spraying material under conditions of high ambient temperature, the amount of construction water added becomes large and the construction body becomes porous, so the amount of Rouseki raw material and sillimanite group raw material added is Make it relatively large.

FIG. 1 is an image diagram of an example of wet spraying construction. The spraying material, which has been prepared in advance into a slurry by adding construction water, is force-fed into the nozzle 1 through the pressure-feeding pipe 5. The spraying material is sprayed from the nozzle 1 while adding the quick-setting agent with compressed air from the quick-setting agent introduction pipe 2 connected near the tip of the nozzle 1. Then, a sprayed construction body (construction body) 4 is formed on a wall surface 3 to be sprayed (for example, a wear brick of a pig iron mixer or a hot metal ladle).
In addition, in FIG. 1, the quick-setting agent is added inside the nozzle 1, but it may be added inside the pressure feeding pipe 5 behind the nozzle 1.

The quick setting agent added within the nozzle 1 or through the pressure feed pipe 5 behind the nozzle 1 may be either liquid or powder.
The liquid quick-setting agent is an aqueous solution of sodium aluminate, potassium aluminate, sodium silicate, sodium phosphate, or the like. Further, these liquid rapid setting agents are combined with a cationic or anionic flocculant, if necessary.
Examples of powder quick-setting agents include sodium aluminate, potassium aluminate, sodium silicate, sodium phosphate, sodium carbonate, calcium chloride, calcium hydroxide, calcium oxide, calcium aluminate, magnesium hydroxide, Portland cement, and sulfuric acid. It is one or more types selected from soil, etc.

The quick-setting agent can be added to the spray material using compressed air. Further, the powder quick setting agent can also be added in a mixed state with the fine refractory powder. It should be noted that the quick setting agent added in the nozzle or in the pressure pipe behind the nozzle and the refractory fine powder mixed therein are not included in the concept of refractory raw material and binder as used in the present invention.

The amount of construction water added to adjust the sprayed material into a slurry form is preferably 5% by mass or more and 15% by mass or less based on 100% by mass of the entire sprayed material. In addition, the amount of quick-setting agent added to the sprayed material (including construction water) adjusted to the shape of slurry is preferably 0.5% by mass or more and 3% by mass or less in terms of external application from the viewpoint of adhesion of the sprayed material.

The sprayed material, which has been prepared in advance into a slurry by adding 10% by mass of construction water to the total of 100% by mass of each example formulation (refractory raw material and binder) shown in Table 1, is pumped using a piston method. The following evaluations were made for the constructed body obtained by force-feeding with a pump, adding 2% by mass of the quick-setting agent to the outside using compressed air at the nozzle, and spraying it onto a refractory vertical wall.
In addition, in Table 1, "other refractory raw materials" refers to alumina-siliceous raw materials other than the alumina-siliceous raw materials listed in the same table (for example, mullite raw materials with a particle size of less than 1 mm), silicon carbide raw materials, alumina raw materials, and silica raw materials. One or more types selected from.

<Residual line change rate>
It was measured at 1200°C and 1450°C in accordance with JIS-2554. 1200°C assumes the temperature on the back side of the construction body during use, and 1450°C assumes the temperature on the operating side of the construction body during use. Specifically, the evaluation was based on the following criteria.
Residual line change rate at 1200℃ ◎ (Excellent): -0.2 or more and less than 0.2, ○ (Good): -0.3 or more and less than -0.2, △ (Acceptable): -0.5 or more -0 Less than .3 or 0.2 or more and less than 0.5, × (impossible): less than -0.5 or 0.5 or more (unit: %)
Residual linear change rate at 1450°C ◎ (Excellent): 0 or more and less than 0.5, ○ (Good): 0.5 or more and less than 1, △ (Acceptable): 1 or more and less than 2 or -0.5 or more and less than 0, × (Not allowed): 2 or more or less than -0.5 (unit: %)

<Residual expansion difference>
Evaluation was made based on the difference in residual line change rate at 1200°C and 1450°C. Specifically, the evaluation was based on the following criteria.
◎ (Excellent): Less than 0.7 〇 (Good): 0.7 or more and less than 1.3, △ (Acceptable): 1.3 or more and less than 2.5, × (Not good): 2.5 or more

<Thermal expansion coefficient>
Measured at 1450°C in accordance with JIS-R2207. Specifically, the evaluation was based on the following criteria.
◎ (excellent): 0.5 or less, 〇 (good): over 0.5 and 0.75 or less, △ (acceptable): over 0.75 and 1 or less, × (impossible): over 1 (unit: %)

<Hot strength>
Measurement was performed in accordance with JIS-R2553 in an atmosphere maintained at an ambient temperature of 1450 degrees. Specifically, the evaluation was based on the following criteria.
◎ (Excellent): 0.5 or more, ○ (Good): 0.3 or more and less than 0.5, △ (Acceptable): 0.1 or more and less than 0.3, × (Unacceptable): Less than 0.1 (Unit: MPa)

<Comprehensive evaluation>
Based on the results of each of the above evaluations, the following criteria were used for evaluation.
◎ (Excellent): When all evaluations are ◎, 〇 (Good): When there is no × and at least one ○ or △, × (Poor): When there is at least one ×

As shown in Table 1, Examples 1 to 10 falling within the scope of the present invention had an overall evaluation of ◎ (excellent) or ○ (good), and good evaluation results were obtained. That is, in Examples 1 to 10, sufficient and appropriate residual expansion properties can be ensured at both 1200°C and 1450°C, and the difference in residual expansion is also small, so peeling of the constructed body can be suppressed in the actual use environment. It is judged that.

Comparative Example 1 is an example that does not contain any sillimanite group raw material. The residual linear change rate at 1200°C was small, resulting in a large residual expansion difference.
Comparative Example 2 is an example that does not contain Rouseki raw material. The residual line change rate at 1450°C became smaller.
Comparative Example 3 is an example in which the content of Rouseki raw material is large. The residual line change rate at 1450°C became too large. In addition, the fire resistance decreased and the hot strength decreased.
Comparative Example 4 is an example in which the content of the sillimanite group raw material is high. The residual line change rate at 1200°C became too large.
As described above, in Comparative Examples 1 to 4, sufficient and appropriate residual expansibility cannot be ensured at both 1200° C. and 1450° C., so it is judged that peeling of the constructed body cannot be suppressed in the actual use environment.

1 Nozzle 2 Rapid setting agent introduction pipe 3 Wall surface 4 Sprayed construction body (construction body)
5 Pressure feed pipe

Claims (5)

A spray material containing a refractory raw material and a binder,
The total amount of the refractory raw material and binder is 100% by mass, contains 1% by mass or more and 15% by mass or less of Rouseki raw material with an average particle size of more than 1 mm, and contains 1% by mass or more and 40% by mass or less of sillimanite group raw material, Furthermore, a spray material containing a total of 50% by mass or more and 90% by mass or less of one or more selected from mullite raw material, chamotte raw material, bauxite raw material, silicon carbide raw material, alumina raw material, and silica raw material. In the total amount of 100% by mass of the refractory raw material and the binder, the Rouseki raw material with an average particle size of more than 1 mm is contained at 3% by mass or more and 8% by mass or less, and the sillimanite group raw material is contained at 5% by mass or more and 20% by mass or less. , the spray material according to claim 1. The total amount of refractory raw materials with a particle size of 1 mm or more is 100% by mass, and in this 100% by mass, mullite is used as a mullite-based raw material with an Al ₂ O ₃ content of less than 90% by mass and containing mullite as a mineral. The spray material according to claim 1 or 2, comprising a total of 50% by mass or more of one or more selected from raw materials, chamotte raw materials, and bauxite raw materials . The spray material according to any one of claims 1 to 3, which is applied to a pig iron mixing car or a hot metal ladle. The spraying material according to any one of claims 1 to 4, which is used for wet spraying construction.

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