JPH06305844A - Mgo-resin-based monolithic refractory - Google Patents

Abstract

PURPOSE:To impart hot strength and corrosion resistance equivalent to that of shaped refractory to a monolithic refractory used for building or repairing various containers for molten metals. CONSTITUTION:This MgO-resin-based monolithic refractory contains 8-20 pts.wt. metal powder or alloy powder and 0.5-5 pts.wt. boron carbide and/or calcium boride based on 100 pts.wt. of the refractory material in the monolithic refractory using a liquid resin as a binder for MgO-based refractory material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MgO-resin type amorphous refractory used for building and repairing various molten metal containers.

[0002]

2. Description of the Related Art Alumina cement, phosphate, etc. have hitherto been used as a binder in an amorphous refractory having room temperature curing property. However, alumina cement has drawbacks such as a decrease in strength in the intermediate temperature range and a tendency to explode when heated. Further, a phosphate-based binder is not always preferable because of its difficulty in fire resistance and corrosion resistance and the quality of steel when it is used for steelmaking. Further, the disadvantage of the amorphous refractory using a basic material, which is weak in the thermal spalling peculiar to the basic material, cannot be overcome by any of these binders.

A carbon bond is known as a strong bond against thermal spalling. As the binder for forming this carbon bond, there are tar and pitch that have been conventionally used, and resin-based binders such as phenol resin that have been frequently used recently. However, carbon bonds are vulnerable to oxidization, and this problem of oxidization becomes a bottleneck in the case of amorphous refractories having a large porosity.

In order to suppress the oxidation of such carbon bonds, a standard refractory material is used, for example, Japanese Patent Laid-Open No. 62-2972.
As disclosed in Japanese Patent Publication No. 73, a method of adding metal powder to an amorphous refractory using a phenol resin is disclosed.
This method is to add 5% by weight or less of metal powder to improve the oxidation resistance and hot strength at the same time. However, the fixed refractory having a low porosity has sufficiently exhibited the oxidation resistance, but Since the regular refractory has a high porosity, it cannot be said that the oxidation resistance is sufficient with this amount of addition. If the addition amount of the metal powder is further increased, the spalling resistance and the corrosion resistance are deteriorated this time. Therefore, the addition amount was suppressed to 5% by weight or less.

Japanese Unexamined Patent Publication (Kokai) No. 62-297273 discloses a method in which a metal powder and calcium hexaboride are used together in a regular refractory material containing a carbon material. Also in this case, the addition amount of the metal powder is 5% by weight or less, and even if it is applied to an amorphous refractory having a high porosity, the oxidation resistance is a method insufficient. Previously, the present inventors have developed an irregular shaped refractory material in which a large amount of metal powder, the amount of which was limited in terms of deterioration of corrosion resistance, was added contrary to common sense (Japanese Patent Application No. 4-337603). This is a resin bond type amorphous refractory in which 8 to 20 parts by weight of metal powder or alloy powder is added to the refractory material, and in terms of oxidation resistance and strength, it exceeds conventional amorphous refractory and is close to regular refractory. It demonstrates its performance.

[0006]

The method of adding a large amount of the metal powder of Japanese Patent Application No. 4-337603 has brought performance exceeding the range of conventional amorphous refractories. The hot strength is inferior to that of a standard refractory material when used in a part such as a hot water contact part of a ladle or a ladle, and further hot strength is required.

[0007]

Means for Solving the Problems As a method for improving hot properties of amorphous refractories, the present inventors have found that by adding boron carbide or calcium boride in addition to a large amount of metal powder, It has succeeded in remarkably improving the strength. That is, the present invention relates to an amorphous refractory using a liquid resin as a binder for a MgO-based refractory material.
Metal powder or alloy powder 8 to 20 parts by weight, boron carbide and / or calcium boride 0.5 to 100 parts by weight
It is an MgO-resin type amorphous refractory material containing 5 parts by weight.

The refractory material used in the present invention is M
As a gO-based refractory material, known magnesia refractory materials such as electro-fused magnesia clinker, sintered magnesia clinker, and natural magnesia clinker alone, or with these materials, synthetic and natural dolomite clinker, magcalcia clinker, magnesia / alumina spinel It can also be used as a mixture with. These refractory materials are MgO
Is preferably 50% by weight or more from the viewpoint of slag corrosion resistance. Further, in the present invention, a carbonaceous material may be used in combination because of its high oxidation resistance.

Further, in the case of an irregular shaped refractory, particularly in the case of castable, the refractory material, metal powder,
The addition of coarse aggregate to a composition composed of a resinous binder is particularly effective in preventing the generation and propagation of cracks during use. This coarse aggregate has a particle size of 5 mm or more, and crushed clinker, granules, brick scraps, etc. can be used, and the material is selected according to the refractory material to be used. 30-200 parts by weight is appropriate for 100 parts by weight of refractory material.

The binder of the present invention uses a liquid resin. The resin as a binder exhibits excellent carbonization rate and bond strength particularly when used in combination with a carbon material, and, unlike tar and pitch, has an optional curability such as room temperature curing or thermosetting. Recently, it is used not only for standard refractories but also for irregular refractories. As the type of resin, in addition to thermosetting resins such as resole type phenolic resins, it is usually used for refractories of thermoplastic resins such as novolak type phenolic resins that become thermosetting when used in combination with a curing agent such as hexamine. What you have can be used arbitrarily.

In order to make these resins room temperature curable, it is possible to add an alkali compound or an alkaline earth compound as a curing accelerator. The liquid resin used also serves as a wetter, and there are a liquid resin itself and a liquid resin in which a solid resin is dissolved in an appropriate solvent such as ethylene glycol. It is also possible to further dilute this liquid substance with a solvent before use.

One of the features of the present invention is that a large amount of metal powder is used. As the metal powder, aluminum, silicon, magnesium, calcium and the like are single or mutual alloys, and specifically, Al, Mg, Si, Al-Mg, Ca-S.
i, Al-Si, Al-Si-Mg, Ca-Si-Mg, Ca-Si-Mg-Al
And so on. The amount used is 8 to 20 parts by weight, preferably 10 parts by weight or more, based on 100 parts by weight of the refractory material. If the amount used is less than 8 parts by weight, improvement in oxidation resistance and strength is insufficient, and if it exceeds 20 parts by weight, further improvement in oxidation resistance and strength cannot be expected, and stress relaxation function decreases. Therefore, in addition to problems in spalling resistance, corrosion resistance also decreases, which is not preferable.

Another feature of the present invention is the use of boron carbide and calcium boride alone or in a mixture of both with a large amount of metal powder. The amount used is 0.5-5 parts by weight per 100 parts by weight of refractory material. If the amount used is 0.5 parts by weight or less, sufficient hot strength cannot be obtained,
If it is 5 parts by weight or more, the corrosion resistance decreases, which is not preferable. The amorphous refractory of the present invention can be used not only for the conventional construction of various containers for hot metal and molten steel in the form of castables, stamps, plastics and mortars, but also for repairs. The method for producing the amorphous refractory material of the present invention is the same as the conventional method. That is, it is manufactured by appropriately adding a conventional dispersant, a deflocculant, etc. according to the kind of the raw material refractory material, metal powder, and amorphous refractory, and adding a liquid resin binder.

[0014]

[Function] The metal powder added to the refractory material reacts with oxygen in the pores of the brick and also binds to the unstable portion of the carbonaceous end of the binder to prevent the reaction of these carbonaceous materials with oxygen. . Further, when a carbonaceous material such as graphite is used, it also serves to prevent this oxidation. At the same time, when aluminum is used as the metal powder, the pores are blocked by volume expansion when it becomes a carbide or oxide, and further when forming magnesia and spinel, so that diffusion of oxygen and slag from the outside of the construction body can be prevented. Cut off and bring the construction body oxidation resistance, corrosion resistance and strength improvement. The effect of adding this metal powder is that the porosity is
With an amorphous refractory that reaches 20%, addition of 5 parts by weight or less does not occur due to free inflow of oxidizing components such as oxygen, and it becomes possible only by using a large amount of metal powder.

On the other hand, boron carbide and calcium boride are
It oxidizes itself to form boron oxide, which reacts with magnesia to form glass and 3MgO.B ₂ O ₃ to form new bonds between refractory materials to improve hot strength and at the same time, stress relaxation function. By this, the adverse effect of adding a large amount of metal is removed and it contributes to spalling resistance. These boron carbide and calcium boride are effective alone, but when they are used together, they are more effective and the corrosion resistance is also improved.

Further, the coexistence of the metal powder with boron carbide or calcium boride has a function of emphasizing the above-mentioned respective actions. That is, the presence of the boron compound promotes spinelization of oxidation products of the metal powder, and the metal powder promotes bond formation between the refractory materials. Furthermore, the slag penetration of basic refractory materials is also characterized by the volume expansion when the metal powder becomes an oxide and the decrease in the pore size due to the formation of new bonds between the refractory materials, and the metal powder and carbonization in the slag. The increase in the slag viscosity due to the dissolution of the oxide formed from boron or calcium boride can be prevented to a considerable extent.

[0017]

[Example] An amorphous refractory having a composition containing a magnesia clinker as a base material as shown in Table 1 was constructed. The construction body
Table 1 also shows the measured values of the physical properties after heat treatment at 1000 ° C. for 3 hours, the oxidation test at 1000 ° C. for 3 hours, and the results of the rotary erosion test with the slag having a basicity (C / S) of 3.4. Note that Examples 1 to 3 and Comparative Example 1 are castable magnesia, Examples 5 and Comparative Example 2 are castable carbon magnesia, Example 4 is a magnesia carbon stamp material, and Example 6 is magnesia. The same amount of coarse aggregate is added. In both Examples and Comparative Examples, workability such as fluidity and curability was good, and there was no problem.

[0018]

[Table 1]

As shown in Table 1, as compared with a sample (Comparative Example 1) in which a large amount of metal powder was added but no boron carbide or calcium boride was added, a sample containing boron carbide or calcium boride was added. In each of the inventions (Examples 1 and 2), it can be seen that the hot strength is excellent because the densification of the construction body is promoted. Regarding the corrosion resistance, the amount of erosion due to the basic slag was improved by the combined addition of metal powder and boron carbide or calcium boride, and the addition of boron carbide and calcium boride together to the metal powder (Example 3) resulted in erosion loss. The amount is significantly reduced.

The above results can be said to be the same for the magnesia-carbon based materials (Examples 4 and 5 and Comparative Example 2). When the amorphous refractory of the present invention was used in the bottom of a replaceable converter, the amount of wear of the conventional regular refractory 0.8 to
We were able to achieve the same level of 0.9 mm / ch and bottom life of 2000 ch. For this reason, the conventional man-hours required for stacking the standard refractory material of 320 hours / person can be reduced to 50 hours / person in the present invention using the irregular-shaped refractory material.

[0021]

EFFECTS OF THE INVENTION According to the present invention, since the metal powder and the boron carbide and calcium boride are added to the irregular shaped refractory in a combined manner, the densification of the construction body is improved, and the hot strength and the corrosion resistance can be improved. . As a result, it becomes possible to extend the life of the irregular refractory to the same level as the regular refractory, and the effect is great.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B22D 41/02 C 7511-4E F27D 1/00 N 7603-4K (72) Inventor Shigeyuki Takanaga Bizen City, Okayama Prefecture Koto Nishi No. 433-2 (72) Inventor Yasutoshi Mizuta No. 67 Nagaoka, Okayama-shi, Okayama 53 (72) Inventor Ichiro Yamashita 1155 Shinzoku, Bizen-shi, Okayama

Claims (1)

[Claims] 1. An amorphous refractory using a liquid resin as a binder for an MgO-based refractory material, wherein 8 to 20 parts by weight of metal powder or alloy powder, 100 parts by weight of refractory material, boron carbide and / or boride is used. An MgO-resin-based amorphous refractory material characterized by containing 0.5 to 5 parts by weight of calcium.