JPH0718658B2 - Hot repair method for molten metal container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a molten metal container such as a converter or a ladle by using a horizontal part of the container, a part that can be made horizontal, or a core. The present invention relates to a method of hot repairing a portion capable of accumulating a repair material (hereinafter referred to as a horizontal portion).

[Conventional technology]

The method by spraying was generally used for hot repair of converters. However, the spray repair method has a problem in corrosion resistance due to the restrictions on the construction because it uses a mixture containing a small amount of coarse particles. As a method for solving this, a method has been developed and put into practical use in which a repair material and water are put into a slurry state for repairing a horizontal portion of a converter and boil-filled by the heat retained by the converter (Japanese Patent Publication No. 57-41671). issue).

This hot repair method is also a very effective method as long as the temperature of the converter is high at 1000 ° C or higher. But the furnace temperature is 400-100
It was found that the tissue strength of the repaired body decreased in the intermediate temperature range of 0 ° C, and a method of making a slurry with a mixture of water and alcohol was developed as a solution to the problem (JP-A-57-136976).
issue).

[Problems to be solved by the invention]

In spite of the above efforts, the repaired body has a lower strength than bricks, and the occurrence of cracks and peeling cannot be avoided.

On the other hand, a casting material that uses coarse particles with a particle size of 50 to 90 mm has been developed to prevent the occurrence of cracks and peeling in a basic ladle (Japanese Patent Publication No. 60-28783). Even if an attempt is made to apply it to the hot repair method, coarse particles will settle during boiling, resulting in particle separation. Further, when the carbonaceous material was mixed into the refractory material other than the coarse particles, the result was that the carbonaceous material was not well compatible with the coarse particles and that peeling occurred.

[Means for solving problems]

When coarse particles are added to a refractory material containing carbonaceous material and it is boil-filled at the point where repair is required in the converter, it is possible to obtain a dense packing without causing the separation of the coarse particles, and also during use. As a result of repeated studies on repair methods that do not cause cracks or peeling, it was found that 30-50 weight parts of coarse particles mainly composed of magnesia with a particle size of 50-130 mm, porosity of 15% or more, and MgO content of 80 weight% or more were selected. With respect to 100 parts by weight of the carbon-containing basic refractory composition containing,
The present invention solves the problems by adding 8 to 15 parts by weight of a mixture of water and alcohol to form a slurry, throwing it into a repaired portion of a molten metal container, and boiling-filling it with the heat retained in the container. Is completed.

[Action]

The hot repair method of the present invention uses a mixture of water and alcohol, and makes the addition amount less than that in the case of not using coarse particles, and makes the boiling time the minimum time at which sufficient filling is achieved, whereby the coarse A dense packing is obtained while preventing separation of grains. Further, since the boiling time is shorter than that of the conventional repair method, the repair time is shortened.

Furthermore, by using coarse particles with a large porosity, the refractory material containing carbonaceous material other than the coarse particles and the binder component enter into the pores on the surface of the coarse particles during the boiling and are hardened. Bonding with other refractory materials is strengthened, the strength of the repaired body is improved, and cracks and peeling are prevented.

One of the characteristics of the coarse particles used in the hot repair method of the present invention is that the porosity thereof is 15%. By using coarse particles having a large porosity, the slurry enters the pores on the surface of the coarse particles together with the refractory material and the binder component containing the carbonaceous material other than the coarse particles during boiling, and the liquid component evaporates, Only the solid content remains in the pores, and by hardening there, the refractory material that entered the coarse particles and the refractory material outside the coarse particles become a continuous body, and the bond between the coarse particles and other refractory materials is strengthened, It improves the strength of the repaired body and prevents cracks and peeling. When the porosity is 15% or less, the pore diameter is inevitably small, and it becomes difficult for the refractory material containing the carbonaceous material other than the coarse particles and the binder component to enter into the pores of the coarse particles together with the liquid, which is preferable. Absent.

Coarse-grained material has a MgO content of 80% by weight or more,
Magnesia, dolomite, or a mixture of these with other refractory materials is used. The one that does not contain carbon
It is preferable because the above-mentioned slurry easily enters the pores.
If the content of MgO is less than 80% by weight, the slag corrosion resistance is lowered, which is not preferable. The size of coarse particles is 50 to 130 mm. If the particle size is 130 mm or more, the coarse particles are too large to sufficiently fill other refractory materials between the coarse particles, and if the particle size is 50 mm or less, the ability to prevent crack propagation and stress concentration due to the coarse particles is insufficient.

The amount of coarse particles used is 30 to 50% by weight of the solid content in the repair material. If this amount is 50% by weight or more, the coarse particles become too large, the coarse particles come into contact with each other, and it is not desirable because the other refractory materials are insufficiently filled. However, the amount of other refractory materials increases, the liquid content inevitably increases, the boiling time also increases, and separation of coarse particles easily occurs.

As a method for producing this coarse particle, a method of granulating with a granulator,
There are methods such as crushing bricks, but if the porosity is 15% or more, the strength of coarse particles tends to decrease. The best way to obtain coarse grains with high porosity without lowering the strength is to crush and use the used bricks of magnesia bricks and stabilized dolomite bricks used in the converter. In particular, it is most preferable to crush and use permanent magnesia waste brick.

As refractory materials other than coarse grains, there are basic refractory materials mainly containing magnesia and carbon materials such as graphite, pitch, and solid phenol resin. Addition of carbon material prevents slag from entering the basic refractory material and improves corrosion resistance. The amount of the carbon material used is 1 to 30 parts by weight based on 100 parts by weight of the refractory material.

The second feature of the present invention is to use a mixture of water and alcohol, and to add 8 to 15 parts by weight to 100 parts by weight of solid content. That is, the amount of liquid is made smaller than in the case where coarse particles are not used, and the boiling time is set to the minimum time at which sufficient filling is achieved, whereby fine particles are obtained while preventing the separation of coarse particles. This liquid volume is 8% by weight
When the amount is less than the above, the boiling time is short and the filling is insufficient, and when the amount exceeds 15% by weight, the boiling time becomes longer and the coarse particles settle.

Using alcohol, while maintaining the fluidity of the slurry, while ensuring sufficient boiling in the intermediate temperature range of the converter,
This is because the boiling is accelerated to shorten the boiling flow time, and moreover, the slurry can easily enter the coarse particles. Further, it also has an effect of suppressing the hydrolysis of the condensed phosphate of the binder. The alcohol used is not particularly limited, but monohydric alcohols such as methanol, ethanol, propanol and butanol are preferable. The mixing ratio of water and alcohol is 95-70: 5-30.

Furthermore, since the boiling time is short, the repair time is shorter and more efficient than in the case of the conventional repair method, and at the same time, since the furnace is not cooled, the adverse effect on the bricks can be reduced.

In the present invention, a condensed phosphate as a binder, for example, pyrophosphate, tripolyphosphate, tetrapolyphosphate,
Metaphosphate, ultraphosphate, etc. are used. The amount used is 1 to 10% by weight in the solid matter.

The repair method of the present invention is a method in which coarse particles, other refractory materials and a binder are simply mixed and placed in a polyethylene bag or the like, a mixed solution of water and alcohol is added, and a horizontal portion of the converter, for example, the bottom of the furnace. Then, the liquid is poured into a repairable portion of a portion that can be leveled, for example, a charging wall or a portion that can store the liquid using a core or the like. Of course, you may use suitable methods other than throwing. Then, the liquid begins to boil with the heat of the furnace, and when the filling of the refractory materials other than the coarse particles into the coarse particles and the penetration into the coarse particles are completed, the boiling ends and the hardening begins. . According to the method of the present invention, even if the coarse particles and other refractory materials are not sufficiently mixed in advance, the mixture and the filling can be satisfactorily performed by boiling.

〔Example〕

Examples 1 to 4 Slurries having the materials shown in Table 1 were placed in an electric furnace framed with refractory bricks and heated and held at 600 ° C, and the slurry was boiled and cured. The coarse particles were obtained by crushing permanent magnesia bricks after use in a converter and sieving them into 50 to 130 mm, and had a porosity of 18% and a compressive strength of 750 Kg / cm ² .

The cured product was taken out after cooling and its physical properties were measured. The results are shown in Table 1.

As a comparative example, the results of the same experiment using the one not using coarse grains and the magnesia brick having a porosity of 12% are shown.

Example 5 At the time of repairing the bottom of the converter, the same material as in Example 1 was put into a polyethylene bag, charged into a repaired part, and cured by boiling.
The time required for the repair was only 8 minutes including the time for charging the material into the bag. On the other hand, in the case of the material of Comparative Example 1, the same operation required 20 minutes.

As a result of operating the converter and receiving steel, the material of Example 1 showed a durability of 8 times, whereas the material of Comparative Example 1 had to be repaired 3 times. It was

〔The invention's effect〕

As shown in Examples 1 to 4, the repairing method of the present invention has better particle dispersion and higher strength after curing than the conventional methods. This is a result of using coarse particles having a high porosity, which is a feature of the present invention, and reducing the amount of the mixed liquid of water and alcohol.

Further, the results of using it in the actual furnace also showed that the repair time was shortened and the durability was improved as shown in Example 5, and the excellence of the present invention was proved.

Continuation of the front page (72) Aina Shiraishi, 1st Fuji-cho, Hirohata-ku, Himeji-shi, Hyogo Pref., Nippon Steel Corporation Hirohata Works (72) Inventor Akira Watanabe 102-12 Shiomikami, Okayama-shi, Okayama (72) Inventor Takeo Okamura 628 Ouchi, Bizen City, Okayama Prefecture (72) Inventor Ichiro Yamashita 783 Uraibe, Bizen City, Okayama Prefecture (56) References JP-A-58-136976 (JP, A)

Claims (2)

[Claims] 1. Coarse grains containing magnesia as a main component having a particle size of 50 to 130 mm, a porosity of 15% or more, and an MgO content of 80% by weight or more.
To 100 parts by weight of the carbon-containing basic refractory composition containing 50 to 50% by weight, 8 to 15 parts by weight of a mixture of water and alcohol is added to form a slurry, and the slurry is thrown into a repaired portion of the molten metal container. A hot repair method for a molten metal container, which comprises boil-filling the container with heat retained in the container. 2. The hot repair method for a molten metal container according to claim 1, wherein the coarse particles are waste materials of magnesia brick or stabilized dolomite brick used in a converter.