JP2006117453A - Metallic compound particle-containing organic resin binder and carbon-containing refractory using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic compound particle-containing an organic resin binder bringing the improvement of the thermal spalling resistance to carbon-containing refractory and the carbon-containing refractory using the organic resin binder. <P>SOLUTION: The organic resin binder contains 1-50 wt.% metallic compound particle (the particle of oxide, carbide, nitride, oxynitride or boride of a metal) having 0.02-10 μm average particle diameter. The carbon-containing refractory uses the organic resin binder The quantity of the metallic compound particle contained in the carbon-containing refractory is 0.01-8.0 wt.%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal compound particle-containing organic resin binder and a carbon-containing refractory using the organic resin binder, in particular, an organic resin binder containing metal compound particles having an average particle size of 0.02 to 10 microns, and The present invention relates to a carbon-containing refractory using the organic resin binder.

Carbon-containing refractories have features such as improved heat-resistant spalling properties due to the addition of carbonaceous raw materials, and also improved wettability to slag. It is important as a refractory that is indispensable now.
Carbon-containing refractories are also commonly used in immersion nozzles and long nozzles used in continuous casting.

In recent years, however, these carbon-containing refractories have been improved and their life has been extended. However, the use conditions of these refractories have become increasingly severe, and there has been a demand for higher durability. ing.
Under these circumstances, the carbon content in the refractory is, for example, about an immersion nozzle used in continuous casting, for example, the initial carbon content was about 30% by weight, but now it is about 20% by weight. Even things are being used. In addition, in furnaces used for secondary refining, in recent years, there has been a growing demand for ultra-low carbon steel production, and the need to suppress carbon pickup as much as possible has emerged, inevitably reducing the carbon content of refractories. Progressing. At present, carbon-containing refractories with a total carbon content of about 3% by weight have been used.

However, in the case of carbon-containing refractories, if the carbon content in the refractory is decreased, the heat-resistant spalling property becomes inferior. Etc., which is likely to occur.
In immersion nozzles and long nozzles used in continuous casting, if the amount of carbon in the alumina-carbon refractory material used is reduced, cracking due to thermal spalling at the initial stage of casting tends to occur. There are drawbacks. Further, magnesia-carbon bricks and alumina-magnesia-carbon bricks used for ladles also have a drawback that their surfaces are easily peeled off by heating and cooling during use.

In addition, even with conventional carbon-containing refractories that have a low carbon content, the occurrence of thermal spalling during use due to changes in operating conditions is unavoidable with current technology. The solution is a major issue for carbon-containing refractories.
In the present invention, “carbon content” means “amount of fixed carbon contained in the refractory” when used in the hot state, and includes an organic binder in addition to the carbon raw material. The carbon of origin is also included.

Various techniques have been proposed for improving the heat spalling resistance of carbon-containing refractories, but sufficient heat spalling resistance has not been obtained yet.
In general, the conventional carbon-containing refractories have a problem that the spalling resistance decreases as the carbon content is reduced. In order to solve this problem, studies have been made to improve the spalling resistance, particularly in the low carbon composition region.
For example, in the step of forming a refractory, there is a method of ensuring spalling resistance by lowering the filling property, increasing the porosity, and decreasing the elastic modulus. However, with such a technique, the denseness of the structure of the refractory is lowered and the corrosion resistance, wear resistance, oxidation resistance, etc. are deteriorated, and it is difficult to use such a refractory practically. It is.

  For example, Patent Document 1 (Japanese Patent Laid-Open No. 5-4861) and Patent Document 2 (Japanese Patent Laid-Open No. 9-87007), etc., as low-carbon carbon-containing refractories have a graphite content of less than 5% by weight. Examples are disclosed. This low-carbon carbon-containing refractory is superior to conventional low-carbon refractories in heat-resistant spalling, but in actual use, it is used by being heated from molten steel for a long time. There is a problem when the sintering of the refractory raw material progresses to increase the elastic modulus and the spalling resistance decreases.

  Patent Document 3 (Japanese Patent Laid-Open No. 11-322405) and Patent Document 4 (Japanese Patent Laid-Open No. 2004-107124) disclose a material using a spinel material in a refractory material containing less than 5% by weight of low carbon. Has been. However, both have the drawbacks that densification progresses due to heat received from the molten steel for a long time in actual use, resulting in a high elastic modulus, and heat resistant spalling properties are deteriorated. Therefore, it is difficult to say that stable heat spalling properties are obtained over a long period of time.

  In general, organic resin binders are generally used for the production of refractories, but technologies aimed at improving thermal characteristics, including improving heat spalling resistance by modifying these organic resin binders. Is also disclosed. For example, in Patent Document 5 (Japanese Patent Laid-Open No. 2002-226276), when carbonaceous powder is mixed in a refractory binder and used as a binder, strength characteristics are improved and oxidation characteristics are excellent. It is disclosed. However, this Patent Document 5 does not disclose an example of improving the heat resistant spalling property, and it is difficult to say that the heat resistant spalling property is improved.

  Further, Patent Document 6 (Japanese Patent Application Laid-Open No. 2002-316865) discloses a heat resistant scrub by dispersing carbon black or graphitized carbon black alone in an organic resin for refractory kneading and using the binder. A technique for improving the polling property is disclosed. According to the present technology, it is considered effective to improve the heat spalling resistance at a low carbon composition, but the addition of carbon black alone according to the present technology has a limit in improving the spalling resistance. Similarly, in Patent Document 7 (Japanese Patent Application Laid-Open No. 2004-67431), graphite particles obtained by heating and graphitizing carbon black, or one or more elements selected from metals, boron, and silicon in carbon black are used. A technique relating to a refractory using a binder for a refractory and a binder for the refractory, characterized in that a graphite particle obtained by heating a simple substance or a compound containing various elements is dispersed in an organic resin is disclosed. However, even with this technology, there is a limit to the improvement of the heat resistant sparing property.

  Patent Document 8 (Japanese Patent Laid-Open No. 3-54155) discloses a technique for improving the spall resistance by adding a substance that disappears by heating. However, the heat-dissipated material used in the present technology has a large diameter of 0.1 to 3.0 mm, and has a defect that the densification of the structure of the refractory is inhibited.

Japanese Patent Laid-Open No. 5-4861 (see Table 1) JP-A-9-87007 (refer to claim 1) Japanese Patent Laid-Open No. 11-322405 (see claim 6, paragraph [0058]) JP 2004-107124 A (refer to claim 1) JP 2002-226276 A (refer to claim 1) JP 2002-316865 A (refer to claim 1, paragraph [0024]) JP 2004-67431 A (see claims 1 and 2) Japanese Patent Laid-Open No. 3-54155 (see claim 1)

  The present invention aims to remedy the drawbacks and problems of the prior art described above, and provides “an organic resin binder containing metal compound particles and an organic resin binder that can improve the heat resistance of carbon-containing refractories” It is a technical problem (objective) to provide a “carbon-containing refractory using”.

The organic resin binder according to the present invention is characterized by “containing metal compound particles having an average particle size of 0.02 to 10 microns” (Claim 1), thereby solving the technical problem (object). It is what.
In addition, the organic resin binder according to the present invention includes “the content of the metal compound particles is 1 to 50% by weight” (Claim 2), “the metal compound particles are a metal oxide, carbide, nitriding. (Claim 3), "The melting point or decomposition temperature or sublimation temperature of the metal compound particles is 1500 ° C or higher" (Claim 4) ), “The organic resin binder is a phenol resin” (Claim 5) is a preferred embodiment of the organic resin binder according to the present invention.

  On the other hand, the carbon-containing refractory according to the present invention is characterized by “use of the organic resin binder” (Claim 6), thereby solving the technical problem (object). In the refractory, the content of the metal compound particles is 0.01 to 8.0% by weight (Claim 7), which is a preferred embodiment of the carbon-containing refractory according to the present invention. is there.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention will be further described together with the description.

  As a result of intensive studies, the present inventors have produced a refractory product using an organic resin binder such as phenol resin or furan resin in which fine metal compound particles are dispersed. The present invention has been completed by finding that the polling performance is greatly improved.

  Usually, a phenol resin is common as an organic resin binder used for production of a carbon-containing refractory. The phenol resin is carbonized by heating, and the remaining carbon plays a role of connecting the raw materials constituting the brick and plays a role of developing the strength of the brick. The present inventors disperse fine particles such as metal oxides, carbides, borides, etc. in organic resins such as phenol resins and furan resins, which remain as fixed carbon even after heating. It has been found that when the resin is used as a binder for forming a carbon-containing refractory, the heat resistant spall property of the obtained refractory is greatly improved.

  Alumina-carbon bricks, magnesia-carbon bricks, etc. obtained by using the above resins are usually fired in a non-oxidizing atmosphere to be the final product, or may be unfired to be the final product. However, in any case, the carbonization of the organic resin binder in the brick proceeds and carbon remains due to the heat received from the molten steel during use. Then, a state in which very fine particles such as metal oxides and carbides are dispersed in the remaining carbon can be obtained.

  Since the metal compound particles are dispersed in the organic resin binder, the surface thereof is completely covered with the organic resin binder. Thereafter, since the organic resin binder is kneaded together with the refractory raw material, the fine particles of the metal compound are dispersed around the refractory raw material while being thinly coated with the organic resin binder. At this time, the fine particles of the metal compound are considered to be dispersed in the continuous organic resin binder film and dispersed in the particles alone. In the present invention, both of these states are considered. Is included.

The present inventors have described that the fine metal compound particles (fine metal compound particles present in the carbon remaining after the organic resin binder is carbonized) play a role in greatly improving the heat resistance spalling property of the refractory. I found out.
The reason why the heat-resistant spalling property is improved is considered to be that very fine metal compound particles have a stress relaxation effect when subjected to thermal shock.

  The present inventors have found that the stress relaxation function against such a thermal shock becomes higher when the fine particles of the metal compound are uniformly dispersed in the refractory. There is a thin film of carbonized and remaining fixed carbon around the fine particles of the metal compound, but the thermal expansion coefficient of the fine metal compound particles is the carbon obtained by carbonization of the organic resin binder present around it. Therefore, microcracks are generated around the metal compound particles by heating and cooling during firing and use. And the presence of this microcrack is considered to have improved the heat-resistant spall property.

  In addition, the carbonization of the organic resin binder proceeds, and the ratio of remaining as fixed carbon is not 100%, but varies depending on the type of organic resin binder, heating conditions, and the like, and varies between several% to 50%. It is common. For this reason, when the organic resin binder in which the metal compound particles are dispersed is heated, the periphery of the metal compound particles is not necessarily completely covered with the remaining carbon, and a part of the metal resin particles protrudes from the remaining carbon film. However, in the present invention, the presence of such metal compound particles is also included in the present invention. The effect of heat resistance is not reduced.

  In the present invention, since fine metal compound particles are used by being dispersed in an organic resin binder, it is possible to disperse the particles in the refractory much more uniformly as compared with the conventional method. This is considered to be the reason why the heat-resistant spall is greatly improved.

  The refractory raw material is usually kneaded at room temperature or under heating with a binder using a kneading machine such as a high speed mixer, wet pan, kneader or the like in the production process. At that time, the periphery of the refractory raw material is covered with a binder such as an added phenol resin. At this time, if fine particles such as alumina, silicon carbide and other oxides and carbides, which are metal compounds, are dispersed in advance in a binder such as a phenol resin to be added, these fine particles are placed around the refractory raw material. It becomes possible to coat uniformly.

Conventionally, when adding ultrafine raw materials of micron order, these ultrafine raw materials are generally kneaded in a mixer at the same time as other refractory raw material powders, and binders are those refractory raw materials. The powder was added after mixing or before mixing.
However, with such a conventional method, it is difficult to uniformly disperse the ultrafine powder raw material, and it is highly possible that the dust is collected from the dust collector during kneading and a predetermined amount is not kneaded. The present invention can also improve the non-uniform dispersibility of such an ultrafine raw material at the same time, and this is one of the features of the present invention.

To disperse the metal compound particles in the organic resin binder, a solvent that easily diffuses into the organic resin binder used is used. First, the fine particles of the metal compound are dispersed in the solvent to prepare a primary dispersion solution. To do. Thereafter, this primary dispersion solution is added to an organic resin binder such as a phenol resin to produce an organic resin binder in which fine particles of a metal compound are dispersed.
The solvent used here is not particularly limited as long as it can diffuse into the organic resin binder. Use organic solvents such as ethanol, ethylene glycol, propanol and other alcohols, ethyl acetate and other esters, toluene, xylene and other aromatic hydrocarbons, kerosene and other aliphatic hydrocarbons, and ketones as solvents. It is possible to select them together. Water can also be used as a solvent.

The primary dispersion solution can be sufficiently added to the organic resin binder at room temperature, but can also be carried out under heating. In particular, when the organic resin binder has a high viscosity and is difficult to mix with the primary dispersion solution, it is effective to perform under heating.
When dispersing the metal compound particles in a solvent, it is effective to use a dispersant. Furthermore, using a mechanical method such as ultrasonic vibration is also effective for dispersion. Also, a mechanical mixing method such as a ball mill or a vibration mill can be used effectively.

Carbon-containing refractories such as alumina-carbon, magnesia-carbon, and spinel-carbon are produced using the organic resin binder in which the metal compound particles thus produced are dispersed.
The final product form of the carbon-containing refractory includes an unfired product that becomes a product only by drying after molding, and a fired product obtained by firing in a non-oxidizing atmosphere once after molding. In addition, an amorphous refractory material that is used without being molded is also mentioned as its product form.

  For products that are used only for drying after molding, the brick is heated by receiving heat from the molten steel during use, and the carbonization of the organic resin binder in the brick progresses due to the heat. Remains as carbon. And the particle | grains of the metal compound contained in this organic resin binder remain in carbon with which the binder remained as fixed carbon content. In addition, since the entire amount of the organic resin binder does not remain as fixed carbon, some of the metal compound particles added in the organic resin binder may be in direct contact with other refractory raw materials. The fine metal compound particles thus introduced serve to improve the heat-resistant spalling property of the refractory.

  On the other hand, for those that are fired once in a non-oxidizing atmosphere after molding, the organic resin used as the binder at the time of firing is carbonized, and the remaining fixed carbon contains fine particles of the metal compound. Become.

  The average particle size of the metal compound particles used in the present invention is preferably 10 microns or less, and preferably 2 microns or less. If it exceeds 10 microns, the effect of improving the heat resistance sparing property is remarkably reduced, which is inappropriate. On the other hand, in the case of ultrafine particles having an average particle size of less than 0.02 microns, it is difficult to disperse the particles in a solvent or in an organic resin binder. Therefore, the average particle size of 0.02 to 10 microns is preferable as the particle size of the metal compound particles used in the present invention.

As the metal compound to be used, a metal oxide, carbide, boride, nitride, oxynitride, or a mixture thereof can be suitably used. The melting point or decomposition temperature or sublimation temperature of these metal compounds is preferably 1500 ° C. or higher. When the temperature is lower than 1500 ° C., these metal compound particles may be melted by receiving heat from the molten steel. In that case, the structure of the metal compound particles is greatly changed and the bonding between the particles occurs. The disadvantage that the effect cannot be obtained occurs, which is not preferable. The compound decomposition caused by heat, for example CaCO ₃ or MgCO ₃ or the like, but the decomposition temperature of 1500 ° C. or less, the melting point of the metal compound produced by decomposition (CaO, MgO) is at 1500 ° C. or higher, such These compounds can be used without any problem in the present invention.

Examples of the metal compound particles suitably used in the present invention include Al ₂ O ₃ , SiO ₂ , MgO, CaO, ZrO ₂ , 3Al ₂ O ₃ .2SiO ₂ , SiC, TiC, BN, B ₄ C, and Si _3. N _{4 and the} like can be mentioned, but the present invention is not limited to these compounds. Furthermore, those metal compounds can be suitably used even if they are crystalline or amorphous.

In the production of a carbon-containing refractory, there are usually many examples in which a phenol resin is used, but the phenol resin can also be suitably used in the present invention. The phenol resin has excellent wettability to the carbon raw material, and is suitable as an organic resin binder for carbon-containing refractory. There are two types of phenolic resins, a thermosetting type (resole type) and a thermoplastic type (novolak type), and any type can be suitably used in the present invention.
Examples of the resin that is carbonized by heating and remains carbon content include, for example, furan resin, epoxy resin, melamine resin, urea resin, etc. other than phenol resin, but in the present invention, the type is not limited. Absent.

  The addition amount of the metal compound particles is suitably in the range of 1 to 50% by weight with respect to the organic resin binder. If it exceeds 50% by weight, it is difficult to disperse the metal compound particles in the organic resin binder, which is inappropriate. On the other hand, when the amount is less than 1% by weight, the amount of the organic resin binder added to add the necessary amount of metal compound particles to the carbon-containing refractory becomes excessive, which is inappropriate.

  A final addition amount of the metal compound particles contained in the carbon-containing refractory and added by dispersion in the organic resin binder is suitably 0.01 to 8% by weight. When the content is less than 0.01% by weight, it is difficult to obtain the effect of improving the heat resistance spalling property. On the other hand, when the content exceeds 8% by weight, the amount of the organic resin binder to be added becomes excessive, and the denseness of the brick decreases. Inappropriate. Moreover, when exceeding 8 weight%, the case where it is inferior to the corrosion resistance and oxidation resistance of a carbon containing refractory material arises, and it is unsuitable.

  In the present invention, the type and particle size of the raw materials used in the production of the carbon-containing refractory are not particularly limited, and conventionally used refractory raw materials can be suitably used. For example, taking carbon-containing refractories for continuous casting as an example, alumina-silica-carbon and zirconia-carbon refractories are generally used, but the types and particle sizes of these raw materials are limited. Not what you want. The same applies to magnesia-carbon refractories, alumina-silicon carbide-carbon refractories, alumina-spinel-carbon refractories, and the like, which are used as lining materials for molten steel pans and hot metal pans. These refractories are generally used in combination with a small amount of metal powder, glass powder, pitch, carbide, boride, etc., but these small amounts of additives are also preferably used in the present invention. be able to.

  In addition, regarding the production method such as kneading, molding, drying, and firing, the production method is not limited in the present invention, and a conventional method can be suitably used.

A feature of the present invention is that fine metal compound particles are dispersed in an organic resin used as a binder in a stage where a carbon-containing refractory is formed, whereby a carbon-containing refractory is formed. In a stage where is used at a high temperature, fine metal compound particles are introduced into fixed carbon formed by carbonization of the binder.
That is, in the present invention, since the metal compound particles are dispersed in advance in an organic resin binder such as phenol resin, these fine particles can be uniformly coated around the refractory raw material. This is a major feature of the present invention, which is why the heat-resistant spalling properties can be greatly improved.

  Next, although the Example of this invention is given with a comparative example and this invention is demonstrated concretely, this invention is not limited by the following Examples.

(Examples 1-6, Comparative Examples 1-7)
The organic resin binder of Examples 1-6 was produced with the content shown in Table 1.
Moreover, the organic resin binder of Comparative Examples 1-6 (the organic resin binder outside the scope of the present invention) was prepared with the contents shown in Table 2, and the organic resin binder of Comparative Example 7 with the contents shown in Table 2 (organic resin). An example of a binder alone, in which no metal compound particles were added, was prepared.

(Examples 7 to 10, Comparative Examples 8 to 12)
The immersion nozzles of the alumina-silica-carbon materials of Examples 7 to 10 and Comparative Examples 8 to 12 were manufactured with the contents shown in Table 3. The shape of the manufactured immersion nozzle is shown in FIG.
The immersion nozzle prepared the alumina-silica-carbon-based kneaded material with the formulation shown in Table 3, and applied this to the site of the main body 1 (the site other than the powder line 2) shown in FIG. For the powder line part 2, a separately prepared zirconia-carbon material was applied.

The raw materials were kneaded using a kneader, and the obtained kneaded material was filled into a rubber mold and then molded using CIP at a pressure of 1200 kg / cm ² . The obtained molded body was dried at 200 ° C. for 3 hours and then fired at 1100 ° C. for 2 hours in a non-oxidizing atmosphere. After firing, the sample was trimmed to obtain an immersion nozzle for a spalling test.
Moreover, a block-shaped sample was produced under the same conditions as above using a part of the kneaded material, and used as a sample for quality measurement.

  A spalling test by hot metal immersion was performed using the immersion nozzle after processing. In the spalling test, in a hot metal held at 1600 ° C., it was charged from room temperature so as to be immersed from the lower end of the immersion nozzle to the center of the powder line part 2, held for 3 minutes, then taken out and air-cooled. did. The results are shown in Table 3. Further, “apparent porosity (%)”, “bulk specific gravity”, and “bending strength (MPa)” were measured as “quality after firing”, and the results are shown in Table 3.

As shown in “Results of Spalling Test” in Table 3, no cracks were observed in the immersion nozzles of the inventive examples (Examples 7 to 10). On the other hand, about the immersion nozzle of Comparative Examples 9-12, it was confirmed that the crack has generate | occur | produced in the discharge hole part. Among these, the immersion nozzle of Comparative Example 10 is an example in which a large amount (22% by weight) of the organic resin binder (organic resin binder containing 40% of BN) of Example 4 was used, and BN (metal compound particles) was used. This is a comparative example containing 8.8% by weight (22 × 40 = 8.8) and a large amount of BN. As shown in Table 3 as “Remarks”, cracks were observed during drying after molding. It was.
In the immersion nozzle of Comparative Example 8, no crack was observed, but as shown in Table 3 as “Remarks”, it was confirmed that the bending strength after firing was extremely low. Further, any immersion nozzles of Comparative Examples 9, 11, and 12 are different from the immersion nozzles of the inventive examples (Examples 7 to 10) as shown in the “post-firing quality” section of Table 3 in bending strength. Showed a low trend.

(Examples 11-15, Comparative Examples 13-16)
Magnesia-carbon bricks of Examples 11 to 15 and Comparative Examples 13 to 16 were produced with the contents shown in Table 4. That is, the formulations shown in Table 4 were kneaded with a wet pan, and the obtained kneaded product was molded at a pressure of 1500 Kg / cm ² to obtain a molded body having a shape of 100 × 200 × 250 (mm). The molded body was dried at 200 ° C. for 5 hours and then fired at 1000 ° C. for 5 hours. The following various tests were implemented using the obtained fired body.

(1) Spalling resistance test A 40 × 40 × 250 (mm) -shaped sample for spalling test was cut out from the obtained fired body. Using this sample, it was immersed in hot metal held at 1500 ° C. After holding for 3 minutes, it was taken out and air-cooled, and cut after cooling. The amount of cracks observed on the cut surface after cutting was measured and digitized. The results are shown in the “Spalling resistance” section of Table 4. Note that a higher value indicates poorer spalling resistance.
(2) Oxidation resistance test A sample having a shape of 50 x 50 x 50 (mm) was cut out from the fired body, held in the atmosphere at 1300 ° C for 3 hours, then cooled, and the sample was cut. The thickness of the decarburized layer on the cut surface was measured and the oxidation resistance was evaluated. The results are shown in the “Oxidation resistance (mm)” section of Table 4.
(3) Corrosion Resistance Test A 40 × 40 × 250 (mm) shape sample was cut out from the fired body, and a slag erosion test was performed at 1600 ° C. using slag having a basicity of 3.0. After the test, the erosion depth of the slag line part was measured to evaluate the corrosion resistance. The results are shown in the “Corrosion resistance (mm)” section of Table 4.
(4) Others About the fired body, “apparent porosity (%)” and “compressive strength (MPa)” were measured as “post-fired quality”, and the results are shown in Table 4.

  From Table 4, it can be seen that Examples 11 to 15 (carbon-containing refractories according to the present invention) are excellent in spalling resistance and have excellent characteristics in corrosion resistance and oxidation resistance.

(Examples 16 and 17, Comparative Example 17)
The long nozzles for continuous casting of Examples 16 and 17 and Comparative Example 17 were produced with the contents shown in Table 5. That is, a long nozzle for continuous casting (Examples 16 and 17) to which the formulation shown in Examples 8 and 9 was applied and a long nozzle (Comparative Example 17) to which the formulation shown in Comparative Example 12 was applied were prepared. The blends of Examples 16 and 17 and Comparative Example 17 were applied to the entire long nozzle.

The long nozzles of Examples 16 and 17 and Comparative Example 17 were kneaded by a kneader, and the obtained kneaded material was filled into a rubber mold and then molded with CIP at a pressure of 1200 kg / cm ² , and then at 200 ° C. for 5 hours. After drying, baking was performed at 1000 ° C. for 5 hours in a non-oxidizing atmosphere. After firing, the sample was processed with a lathe and then coated with an antioxidant to obtain a final product. And this long nozzle is attached to a ladle having a capacity of 220 t, and max. Up to 12 ch was used. The casting time for 1ch was about 35 minutes.

  Table 5 shows the results of using 10 long nozzles to which each formulation was applied. As a result, as shown in the “Usage results” section of Table 5, the long nozzles of Examples 16 and 17 had max. It was used without any problems without vertical cracks in use up to 12ch. On the other hand, in the long nozzle of Comparative Example 17, two of the ten nozzles had vertical cracks in the main body at the first channel of the initial casting. From this result, it was found that the carbon-containing refractory according to the present invention has an excellent effect in terms of spalling resistance.

(Example 18, Comparative Example 18)
As Example 18, a magnesia-carbon brick to which the formulation used in Example 13 was applied was produced. In addition, as Comparative Example 18, a magnesia-carbon brick to which the formulation used in Comparative Example 15 was applied was produced.
The obtained magnesia-carbon bricks of Example 18 and Comparative Example 18 were applied to a slag line portion of a 220 t molten steel pan and used in an actual furnace.

The molten steel pan to which the magnesia-carbon brick of Example 18 was applied showed the durability up to 60 ch, and was repaired as planned. On the other hand, in the pan in which the magnesia-carbon brick of Comparative Example 18 was applied to the slag line portion, the surface peeling of the brick partially occurred at the stage where 20 ch was used. This surface peeling is presumed to have occurred due to thermal spalling during repeated use of the molten steel pan. Although this molten steel pan was used continuously thereafter, the slag line part was greatly damaged due to the influence of peeling when 45ch was used, and it was repaired at a stage where it did not reach the plan.
From the above, it has been clarified that the carbon-containing refractory of the present invention is excellent in heat-resistant spall property.

  As described in detail above, the present invention provides a `` metal compound particle-containing organic resin binder and a carbon-containing refractory using the organic resin binder '' that brings about an improvement in heat resistance of the carbon-containing refractory. Its availability is very remarkable.

It is a figure which shows the shape of an immersion nozzle.

Explanation of symbols

1 Body part 2 Powder line part

Claims (7)

An organic resin binder comprising metal compound particles having an average particle size of 0.02 to 10 microns. The organic resin binder according to claim 1, wherein the content of the metal compound particles is 1 to 50% by weight. The organic resin binder according to claim 1 or 2, wherein the metal compound particles are made of at least one selected from metal oxides, carbides, nitrides, oxynitrides, and borides. The organic resin binder according to any one of claims 1 to 3, wherein the melting point or decomposition temperature or sublimation temperature of the metal compound particles is 1500 ° C or higher. The organic resin binder according to any one of claims 1 to 4, wherein the organic resin binder is a phenol resin. A carbon-containing refractory using the organic resin binder according to any one of claims 1 to 5. The carbon-containing refractory according to claim 6, wherein the content of the metal compound particles is 0.01 to 8.0% by weight.

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