Hot repair spray material
Technical field
[0001]
　The present invention relates to a hot repair spray material which is used, for example, for hot repair of converter, degassing furnace, ladle, and other kiln furnace linings and is sprayed on a surface to be repaired together with construction water.
　In the present invention, “hot repair” refers to repair in a state where the temperature of the surface to be repaired is approximately 600° C. or higher.
Background technology
[0002]
　For example, in a converter, hot-melt repair of the melted portion of the lining is performed. As a hot repair method, there is known a method in which a spray material containing a refractory raw material and a binder is sprayed together with construction water on a melted portion of the lining.
[0003]
　Conventionally, spraying materials used in this method have often used phosphates and silicates as binders, but phosphates and silicates form low melting point compounds with slag. Therefore, it has the drawback of poor durability.
[0004]
　Therefore, in recent years, instead of a phosphate or a silicate for the purpose of imparting slag penetration resistance and strength to a spray-constructed body, a substance that forms a carbon bond hot, specifically carbon such as phenol resin Quality resin is used (for example, refer to Patent Document 1).
Advanced technical literature
Patent literature
[0005]
Patent Document 1: Japanese Patent Laid-Open No. 2010-235340
Summary of the invention
Problems to be Solved by the Invention
[0006]
　In Patent Document 1, in order to prevent the softening of the carbonaceous resin from being delayed, a part of the carbonaceous resin is blended together with the granulated powder in a state where the granulated product is formed. As long as it is formed, heat cannot be easily transferred to the carbonaceous resin. For this reason, the softening delay of the carbonaceous resin is unavoidable, and when the sprayed material reaches the surface to be repaired, it rebounds and there is a problem that the adhesion to the surface to be repaired is poor.
[0007]
　The problem to be solved by the present invention is to improve the adhesiveness to the surface to be repaired in the hot repair spray material.
Means for solving the problem
[0008]
　The present inventors considered that it is effective to use a phenol resin as the carbonaceous resin in order to improve the adhesiveness to the surface to be repaired (hereinafter, simply referred to as “adhesiveness”). That is, the phenol resin is likely to aggregate and exhibit proper viscosity (adhesiveness) at the moment of being sprayed on the surface to be repaired. Further, the present inventors have selected a magnesia raw material as a refractory raw material from the viewpoint of improving durability such as slag penetration resistance. Further, in order to solve the above-mentioned problems, the present inventors have made further studies by paying attention to the mixing ratio of the magnesia raw material and the phenol resin, particularly the mixing ratio of the ultrafine powder region, and have arrived at the present invention. ..
[0009]
　That is, according to one aspect of the present invention, the following hot repair spray material is provided.
　The content of the magnesia raw material is 65 mass% or more and 95 mass% or less, the phenol resin is 0.5 mass% or more and 10 mass% or less,
　and the content of the magnesia raw material having a particle size of less than 20 μm is 5 mass% or more and 30 mass% or less. Hereinafter, the content of the phenol resin having a particle size of less than 20 μm is 0.3% by mass or more and 9% by mass or less, and
　“the content of the magnesia raw material having the particle size of less than 20 μm/the content of the phenol resin having the particle size of less than 20 μm is included. Spraying material for hot repair with "amount" of 0.6 or more and 30 or less.
Effect of the invention
[0010]
　ADVANTAGE OF THE INVENTION According to this invention, the compounding ratio of the magnesia raw material and the phenol resin in a very active ultrafine powder area of ​​less than 20 μm is within a specific range, and the magnesia raw material and the phenol resin are well balanced in the ultrafine powder area. Since it exists, a matrix having an appropriate viscosity (adhesiveness) is formed at the moment of spraying, and a uniform carbon bond is formed in this matrix. This improves the adhesion.
MODE FOR CARRYING OUT THE INVENTION
[0011]
　The hot repairing spray material of the present invention contains 65 mass% or more and 95 mass% or less of a magnesia raw material and 0.5 mass% or more and 10 mass% or less of a phenol resin.
　When the content of the magnesia raw material is less than 65% by mass, durability such as corrosion resistance (slag penetration resistance) is deteriorated. When the content of the magnesia raw material exceeds 95% by mass, the content of the phenol resin becomes relatively small and the adhesiveness decreases.
　Further, if the content of the phenol resin is less than 0.5% by mass, the effect of forming a carbon bond is weakened and the adhesion is lowered. When the content of the phenol resin exceeds 10% by mass, a large amount of volatilization from the phenol resin causes the structure of the spray-applied body to become porous and the spray-applied body strength decreases.
[0012]
　As described above, the present invention limits the blending ratio of the magnesia raw material and the phenol resin in the ultrafine powder area where the particle diameter is less than 20 μm. That is, the content of the magnesia raw material having a particle size of less than 20 μm is 5% by mass or more and 30% by mass or less, and the content of the phenol resin having a particle size of less than 20 μm is 0.3% by mass or more and 9% by mass or less. The ratio “content of the magnesia raw material having a particle size of less than 20 μm/content of the phenol resin having a particle size of less than 20 μm” (hereinafter, this content ratio is simply referred to as “content ratio”) is 0.6 or more and 30 or more. It is the following. The reason for limiting the blending ratio such as the content ratio is as follows.
[0013]
　When the content of the magnesia raw material having a particle size of less than 20 μm is less than 5% by mass, the aggregating effect (adhesion retention function by agglomeration) of the ultrafine powder magnesia raw material is weakened and the adhesion is lowered. If the content of the magnesia raw material having a particle size of less than 20 μm exceeds 30% by mass, the aggregation effect becomes excessive and the viscosity becomes high, so the dischargeability at the time of spraying is deteriorated, and as a result, the adhesiveness also decreases.
[0014]
　If the content of the phenol resin having a particle size of less than 20 μm is less than 0.3% by mass, the reaction for forming a carbon bond will be delayed and the adhesion will be reduced. If the content of the phenolic resin having a particle size of less than 20 μm exceeds 9% by mass, it will float due to dust generation during spraying and the adhesiveness will decrease. Furthermore, since the suspended ultrafine powdered phenol resin burns, there is also the problem that the construction site cannot be seen.
[0015]
　When the content ratio is less than 0.6 (when there is much ultrafine powdered phenolic resin), the rate of volatilization of the phenolic resin becomes faster and the sprayed structure contracts at a stretch and the sprayed structure floats at the adhesive interface, resulting in poor adhesion. descend. Then, as the adhesive force is reduced, flaking occurs due to the dead weight of the spray-constructed body and the spray pressure. On the other hand, when the content ratio is more than 30 (when the amount of the ultrafine powdered phenolic resin is small), the strength after adhesion cannot be maintained and the sprayed construction body falls off. The preferable range of this content ratio is 0.6 or more and 20 or less.
[0016]
　As the magnesia raw material and the phenol resin used in the present invention, those generally used (commercially available) as a raw material for the hot repair spraying material can be used. The particle size composition of the magnesia raw material and the phenol resin may be adjusted so that the content of the particles having a particle size of less than 20 μm and the content ratio fall within the predetermined range described above. Here, in the hot repairing spray material of the present invention, a part of the magnesia raw material can be an aggregate, so that, for example, in the particle size region of less than 4 mm in particle size, the content and the content ratio of particles less than 20 μm are as described above. The particle size may be adjusted to fall within the predetermined range.
　The term "magnesia raw material" as used in the present invention refers to one having a MgO content of 60% by mass or more, and includes not only natural magnesia raw materials but also magnesia bricks and scraps of magnesia/carbon bricks.
　Further, the “particle size” in the present invention means a sieve mesh, and, for example, a particle size of less than 20 μm means one passing through a sieve mesh of 20 μm.
[0017]
　The hot repairing spray material of the present invention can contain pitch of 0.5% by mass or more and 10% by mass or less in addition to the magnesia raw material and the phenol resin. By including the pitch in an amount of 0.5% by mass or more and 10% by mass or less, the strength of the sprayed construction product is improved and the durability can be improved.
[0018]
　In addition to the magnesia raw material, phenolic resin and pitch, the hot repairing spray material of the present invention includes other refractory raw materials such as dolomite raw material and carbon raw material, metal powder, organic fiber, etc. A material generally used as a raw material of the material can be appropriately contained.
[0019]
　The hot repair spray material of the present invention is sprayed on the surface to be repaired together with the construction water in the same manner as the conventional hot repair spray material, but the spraying conditions such as the amount of construction water and the spraying method are the same as the conventional ones. Good.
Example
[0020]
　Table 1 shows the raw material composition and the evaluation results of the examples and comparative examples of the present invention. The evaluation items and evaluation methods in Examples and Comparative Examples are as follows. In Table 1, "other raw materials" are dolomite raw material, carbon raw material, and metal powder.
[0021]

　The spray material of each example was sprayed on a vertical surface (surface to be repaired) of a magnesia carbon brick heated to about 1000° C. by using a conventional dry spraying machine to form a spraying work body. The amount of construction water added was 20 to 40% by mass when applied to 100% by mass of the spray material.
　Adhesiveness is evaluated by the adhesion ratio of the sprayed material to the surface to be repaired, and when the ratio of the amount of the sprayed material to the surface to be repaired is 80 mass% or more, ◯ (good), 60 mass% or more When the content was less than 80% by mass, it was evaluated as Δ (OK), and when it was less than 60% by mass, it was evaluated as X (impossible).
[0022]
Using
　a rotary erosion tester, a sample of a predetermined size cut out from a spray-constructed body was eroded at 1650 to 1700°C for 5 hours using a C/S = 3.4 converter slag and steel slag as an erosion agent. Let The maximum amount of erosion loss in each example was measured and the reciprocal thereof was calculated, and the relative value was calculated with the reciprocal of Example 1 being 100. The larger this relative value, the better the corrosion resistance. In the evaluation of corrosion resistance, when this relative value was 80 or more, it was evaluated as ◯ (good), when it was 70 or more and less than 80, it was evaluated as Δ (acceptable), and when it was less than 70, it was evaluated as x (impossible).
[0023]

　A sample having a predetermined size cut out from the sprayed body was measured for compressive strength at room temperature in accordance with JIS R2575, and a relative value was obtained with the compressive strength of Example 1 being 100. The larger this relative value is, the higher the strength of the sprayed construction body is. In the evaluation of the strength of the sprayed construction body, when this relative value was 80 or more, it was evaluated as ◯ (good), when it was 70 or more and less than 80, it was evaluated as Δ (acceptable), and when it was less than 70, it was evaluated as x (impossible).
[0024]

　The nozzle tip of the dry sprayer was visually observed at the time of spraying, and the case of discharging without pulsation was rated as ◯ (good), and the case of pulsation was rated as x (not possible).
[0025]

　When all of the evaluation items are all ○, it is ○ (good), when △ is 1 to 3 and the others are ○, it is Δ (OK), and when one of them is ×, it is ×. (No)
[0026]
[Table 1]

[0027]
　As shown in Table 1, in Examples 1 to 6 which are within the scope of the present invention, the adhesion evaluation was good (good) or good (good), and the overall evaluation was also good.
[0028]
　Comparative Example 1 is an example in which the content of the magnesia raw material is small. Since there are few magnesia raw materials that contribute to the improvement of corrosion resistance (slag penetration resistance), sufficient corrosion resistance cannot be obtained.
　Comparative Example 2 is an example in which the content of the magnesia raw material is large. The content of the phenolic resin was relatively small, and the adhesiveness was so low that a sufficient sprayed product could not be obtained. Therefore, a sample for evaluating the corrosion resistance and the strength of the sprayed construction body could not be obtained.
[0029]
　Comparative Example 3 is an example in which the content of the magnesia raw material having a particle size of less than 20 μm is small. The cohesive effect of the magnesia raw material having a particle size of less than 20 μm was weakened, and the adhesion was lowered.
　Comparative Example 4 is an example in which the content of the magnesia raw material having a particle size of less than 20 μm is large. The agglomeration effect became excessive and the dischargeability at the time of spraying was deteriorated. As a result, the adhesiveness was so low that a sufficient sprayed product could not be obtained. Therefore, a sample for evaluating the corrosion resistance and the strength of the sprayed construction body could not be obtained.
[0030]
　Comparative Example 5 is an example in which the content of the phenol resin is low and the content ratio is high (the content of the phenol resin having a particle size of less than 20 μm is low). Since the amount of the phenolic resin that contributes to the improvement of the adhesiveness was small, the adhesiveness was so low that a sufficient sprayed product could not be obtained. Therefore, a sample for evaluating the corrosion resistance and the strength of the sprayed construction body could not be obtained.
　Comparative Example 6 is an example in which the content of the phenol resin is large and the content ratio is low (the content of the phenol resin having a particle size of less than 20 μm is large). The volatilization rate of the phenol resin was increased, and the phenol resin having a particle size of less than 20 μm floated due to dust generation during spraying, resulting in a decrease in adhesion.
The scope of the claims
[Request item 1]
　The content of the magnesia raw material is 65 mass% or more and 95 mass% or less, the phenol resin is 0.5 mass% or more and 10 mass% or less,
　and the content of the magnesia raw material having a particle size of less than 20 μm is 5 mass% or more and 30 mass% or less. Hereinafter, the content of the phenol resin having a particle size of less than 20 μm is 0.3% by mass or more and 9% by mass or less, and
　“the content of the magnesia raw material having the particle size of less than 20 μm/the content of the phenol resin having the particle size of less than 20 μm is included. Spraying material for hot repair with "amount" of 0.6 or more and 30 or less.
[Request item 2]
　The hot repairing spray material according to claim 1, which contains 0.5% by mass or more and 10% by mass or less of pitch.
[Request item 3]
　The hot repairing spray material according to claim 1 or 2, wherein "content of the magnesia raw material having a particle size of less than 20 µm/content of the phenol resin having a particle size of less than 20 µm" is 0.6 or more and 20 or less.