JP6795773B1 - Baking repair material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a baking repair material having excellent spreadability in heat by further improving expandability by means other than a fluidization accelerator. Baking repair materials according to the present invention include non-baked olivine 5 to 60% by mass, magnesia 10 to 65% by mass, coal tar pitch 9 to 20% by mass, p-octylphenol of 5% by mass or less, and 30% by mass. Contains less than% iron powder. [Selection diagram] None

Description

The present invention relates to a baking repair material for hot repairing various smelting furnaces, molten metal containers, and the like.

Hot baking materials are used as repair materials to be applied to damaged parts of various refining furnaces such as converters. As such a hot baking material, a powder or granular material obtained by mixing a fire-resistant raw material such as magnesia and a binder that forms a carbon bond with heat is put into a damaged part in the furnace, melted and developed by the heat in the furnace, and baked for repair. (Patent Document 1, Patent Document 2).

Japanese Unexamined Patent Publication No. 2008-285379 Japanese Unexamined Patent Publication No. 11-278948

Patent Document 1 discloses a baking repair material containing 0.1 to 1% by weight of a fluidization accelerator with respect to 1% by weight of a binder that forms a carbon bond hot. Further, Patent Document 2 discloses a baking repair material using 10% by weight or less of polyhydric alcohol, heavy oil, light oil, creosote oil, anthracene oil, wax oil and the like as a fluidization accelerator. All of these prior documents recognize the issue of improving expandability. However, the effect of the fluidization accelerator alone was still insufficient.

Therefore, an object to be solved by the present invention is to provide a baking repair material having excellent expandability in heat by further improving expandability by means other than a fluidization accelerator.

As a result of various studies, the present inventors have focused on the fact that the influence of the type of aggregate on the expandability of the baked material has not yet been investigated. Therefore, when the effects of various aggregates on the expandability of the baked material were investigated, it was found that good expandability can be obtained when non-fired olivine is used. The reason is not necessarily clear, but it is considered that the porosity of the uncalcined olivine is lower than the porosity of the magnesia clinker, so that the absorption of the binder component is reduced, and thus the flow effect of the binder can be sufficiently exerted. Further, since the unfired olivine contains water of crystallization and releases the water of crystallization hotly, it is considered that the binder is agitated hotly and the flow effect of the binder is further enhanced. The porosity of the unfired olivine is generally smaller than the porosity of the calcined olivine, for example, 3% by volume or less.

The baking repair material according to the present invention is non-fired olivine 5 to 60% by mass, magnesia 10 to 65% by mass, coal tar pitch 9 to 20% by mass, 5% by mass or less of p-octylphenol , and 30 % by mass or less of iron. It is characterized by containing powder and aluminum powder of 5% by mass or less .

According to this configuration, a baking repair material having excellent hot deployability can be obtained. In addition, the corrosion resistance of the baking repair material can be improved.

Hereinafter, preferred embodiments of the present invention will be described. However, the scope of the present invention is not limited by the preferred embodiments described below.

Baking repairing material according to the present invention, as one embodiment, prior SL aluminum powder is preferably a powder of at least one of aluminum metal and aluminum alloys.

According to this configuration, the corrosion resistance of the baking repair material can be improved.

Further features and advantages of the present invention will be further clarified by the following illustration of exemplary and non-limiting embodiments.

Hereinafter, embodiments of the baking repair material according to the present invention will be described. The baking repair material according to the present invention includes non-firing olivine, magnesia, coal tar pitch, p-octylphenol, and iron powder. Further, an aluminum material may be optionally included. Hereinafter, each component will be described.

The baking repair material according to the present invention contains 5 to 60% by mass of unfired olivine. Here, if the content of the unfired olivine is less than 5% by mass, the expandability of the baking repair material may decrease. On the other hand, if the content of the non-fired olivine exceeds 60% by mass, the porosity of the work piece after baking becomes excessively high, and the corrosion resistance of the baking repair material may decrease. The particle size of the non-fired olivine is preferably adjusted to coarse, medium, and fine so that the baked repair material structure has a densely packed structure. This point is the same as the conventional material.

The baking repair material according to the present invention contains 10 to 65% by mass of magnesia. Here, if the content of magnesia is less than 10% by mass, the expandability is significantly deteriorated, so that the repair material does not spread and does not adhere to the repaired portion, and it solidifies and continues to burn, so that it takes time to cure. On the other hand, when the content of magnesia exceeds 65% by mass, the expandability is inferior.

The baking repair material according to the present invention contains a coal tar pitch of 9 to 20% by mass. The coal tar pitch fluidizes at high temperatures and then forms carbon bonds, thus acting as a binder that imparts corrosion resistance and adhesive strength to the baked repair material. Here, if the content of the coal tar pitch is less than 9% by mass, the expandability, adhesiveness and corrosion resistance of the baking repair material may decrease. As the amount of coal tar pitch added is larger, the expandability of the baking repair material is improved and the carbon bonds formed are increased, so that the adhesiveness and corrosion resistance of the baking repair material are improved. However, if the amount of coal tar pitch added exceeds 20% by mass, the burning time of the baking repair material becomes long, so that the time required for curing the baking repair material may become excessively long.

The baking repair material according to the present invention contains 5% by mass or less of p-octylphenol. Since p-octylphenol has a lipophilic octyl group and a hydrophilic hydroxy group, it has an effect of improving the compatibility between coal tar and aggregate and enhancing the expandability of the baking repair material. The effect of improving the expandability by adding p-octylphenol can be obtained by adding a very small amount of p-octylphenol, but it is more preferable to add 1% by mass or more of p-octylphenol. When the baking repair material is baked, p-octylphenol is burned and removed, and becomes a hole in the construction body after baking. Therefore, if the amount of p-octylphenol added exceeds 5% by mass, the porosity of the work piece after baking may increase and the corrosion resistance may decrease. In view of the above matters, it is preferable that the content of p-octylphenol in the baking repair material according to the present invention is 1 to 5% by mass.

The baking repair material according to the present invention contains 30% by mass or less of iron powder. Since iron powder has a high thermal conductivity, the addition of iron powder increases the thermal conductivity of the baking repair material, and the material temperature rises faster when the baking repair material flows between heat and receives heat. This promotes carbonization of the binder and can significantly reduce the curing time. The effect of increasing the thermal conductivity by adding iron powder can be obtained by adding a small amount of iron powder, but it is more preferable to add 5% by mass or more of iron powder. On the other hand, if the iron powder content exceeds 30% by mass, the iron powder may settle and hinder the adhesion between the baking repair material and the material to be repaired, resulting in a decrease in corrosion resistance. In view of the above matters, it is preferable that the iron powder content in the baking repair material according to the present invention is 5 to 30% by mass.

The baking repair material according to the present invention preferably further contains 5% by mass or less of an aluminum material. Here, the aluminum material is at least one of aluminum and an aluminum alloy. Corrosion resistance of the baking repair material can be improved by adding the aluminum material. The effect of improving the corrosion resistance by adding the aluminum material can be obtained by adding a small amount of the aluminum material, but it is more preferable to add 1% by mass or more of the aluminum material. Further, if the content of the aluminum material exceeds 5% by mass, the corrosion resistance of the baking repair material may decrease. In view of the above matters, it is more preferable that the content of the aluminum material in the baking repair material according to the present invention is 1 to 5% by mass.

The baking repair material according to the present invention can be obtained by mixing the above-mentioned constituent components by a known method.

The baking repair material according to the present invention can be used in a repair method for hot repairing various smelting furnaces, molten metal containers, etc., similarly to known baking repair materials.

It should be understood that with respect to other configurations, the embodiments disclosed herein are exemplary in all respects and the scope of the invention is not limited thereto. Those skilled in the art will be able to easily understand that modifications can be made as appropriate without departing from the spirit of the present invention. Therefore, another embodiment modified without departing from the spirit of the present invention is naturally included in the scope of the present invention.

Examples and comparative examples are shown below, and the present invention will be described in more detail.

[Material used]
Commercially available non-fired olivine, magnesia, coal tar pitch, p-octylphenol, iron powder, and aluminum powder (example of aluminum material) were used in each case.

[Sample preparation]
Each material weighed according to the composition shown in Tables 1 to 5 described later was put in a bag and mixed well to obtain a baking repair material of each example of Examples and Comparative Examples.

In Examples 1 to 6 and Comparative Examples 1 to 3 (Table 1), the content of uncalcined olivine was changed. In Examples 7 and 8 and Comparative Examples 4 and 5 (Table 2), the coal tar pitch content was varied. In Examples 9 and 10 and Comparative Examples 6 and 7 (Table 3), the iron powder content was changed. In Examples 11 and 12 and Comparative Examples 8 and 9 (Table 4), the content of p-octylphenol was changed. In Examples 13 and 14 and Comparative Example 10 (Table 5), the content of aluminum powder was changed.

[Sample evaluation]
The expandability, curing time, adhesiveness, and corrosion resistance of the baking repair materials of each of the Examples and Comparative Examples were evaluated by the following methods. In addition, a comprehensive evaluation was performed based on the evaluation of the above four items.
Comprehensive evaluation A: A has 4 items, or A has 3 items and B has 1 item. Comprehensive evaluation B: A has 2 items and B has 2 items. Comprehensive evaluation C: Comprehensive evaluations A, B, and Items that do not correspond to D Comprehensive evaluation D: Items that have one or more items of D

《Expansion evaluation》
800 g of the baking repair agent was put onto the castable test plate in the furnace kept at 1000 ° C. After extinguishing the fire, the board was taken out and the diameter at which the baking material spread was measured. It is recognized that the larger the diameter, the higher the expandability. The relationship between the symbols in the table and the diameter in the expansiveness evaluation is shown below.
A: 250 mm or more B: 210 mm or more and less than 250 mm C: 180 mm or more and less than 210 mm D: less than 180 mm

《Adhesion evaluation》
A castable test plate having an area of 0.01 m ² was heated in a box-type furnace until the surface temperature of the test plate reached 1000 ° C. An iron cylindrical metal frame (inner diameter 70 mm, height 20 mm) was placed on a heated test plate, 150 g of a sample was put into the metal frame, and the sample was held as it was until the fire was extinguished. After the test plate after extinguishing the fire was taken out and cooled, a load was applied from the side surface of the iron cylindrical metal frame, and the maximum load at which the baking repair material was peeled off from the test plate was measured. The maximum load was divided by the adhesive area to obtain the value of the adhesive strength. The relationship between the symbols in the table and the adhesive strength is shown below.
A: 2.0 MPa or more B: 1.5 MPa or more and less than 2.0 MPa C: 1.0 MPa or more and less than 1.5 MPa D: less than 1.0 MPa

<< Curing time evaluation >>
In the adhesiveness evaluation test, the time required for the baking repair material to extinguish the fire was measured as the curing time. The relationship between the symbols in the table and the curing time is shown below.
A: Less than 4 minutes B: 4 minutes or more and less than 5 minutes C: 5 minutes or more and less than 6 minutes D: 6 minutes or more

<< Corrosion resistance evaluation >>
The sample was filled in a refractory container, fired at 1000 ° C. for 3 hours, and then cut into a predetermined shape to prepare a test sample. In the rotary drum erosion test apparatus, the slag (CaO / SiO2 = 3) and the baking repair material were kept at 1650 ° C. for 3 hours. After the test, the sample was cut in a direction perpendicular to the working surface, and the erosion area of the cut surface was measured. The erosion index represents the erosion area when the erosion area of Comparative Example 1 is 100. It is recognized that the smaller the erosion index, the higher the corrosion resistance. The relationship between the symbols in the table and the erosion index is shown below.
A: Less than 90 B: 90 or more and less than 100 C: 100 or more and less than 110 D: 110 or more

〔Test results〕
Tables 1 to 5 show the compositions and evaluation results of each of the baking repair materials of Examples and Comparative Examples. Examples 1 to 6 containing a preferable amount of unfired olivine, magnesia, and coal tar pitch have better expandability, adhesiveness, and hardening as compared with Comparative Examples 1 to 3 in which the content of unfired olivine or magnesia is small. Shown the time.

Table 1: Relationship between the content of unfired olivine and the evaluation results

Examples 7 and 8 containing a preferred amount of coal tar pitch showed good corrosion resistance. On the other hand, Comparative Example 4 in which the content of coal tar pitch was smaller than the preferable range had inferior corrosion resistance to Examples 7 and 8. Further, Comparative Example 5 in which the coal tar pitch content was larger than the preferable range showed high corrosion resistance, but the curing time was long.

Table 2: Relationship between coal tar pitch content and evaluation results

Examples 9 and 10 containing a preferable amount of iron powder showed good corrosion resistance. On the other hand, Comparative Examples 6 and 7 in which the iron powder content was not in the preferable range were inferior in corrosion resistance.

Table 3: Relationship between iron powder content and evaluation results

Examples 11 and 12 containing a preferable amount of p-octylphenol showed good corrosion resistance. On the other hand, Comparative Examples 8 and 9 in which the content of p-octylphenol was not in the preferable range were inferior in corrosion resistance.

Table 4: Relationship between p-octylphenol content and evaluation results

Examples 13 and 14, which contained a preferable amount of aluminum powder, showed good corrosion resistance. On the other hand, Comparative Example 10 in which the content of the aluminum powder was not in the preferable range was inferior in corrosion resistance.

Table 5: Relationship between aluminum powder content and evaluation results

As described above, it is clear that the baking repair material according to the present invention is excellent in deployability by improving expandability, and further improves corrosion resistance and adhesiveness.

The present invention can be used as a baking repair material for hot repairing various refining furnaces, molten metal containers, etc., for example.

Claims (2)

Non-fired olivine 5-60% by mass, magnesia 10-65% by mass, coal tar pitch 9-20% by mass, 5% by mass or less p-octylphenol , 30 % by mass or less iron powder and 5% by mass or less aluminum powder Baking repair material including. Before SL aluminum powder, baking repairing material according to claim 1, wherein the powder comprising at least one aluminum metal and aluminum alloys.