JP3151202B2 - Refractory materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to refractory materials used for furnace materials and nozzles of furnaces such as steelmaking, steelmaking, and other nonferrous metals.

[Prior art]

For bricks such as furnace materials and nozzles that are in contact with molten metal such as molten steel, in order to minimize the erosion due to the molten metal and increase the number of serviceable times, bricks with low wettability to the molten metal are demanded. Conventionally, carbonaceous bricks have been used as bricks. Carbonaceous bricks have reduced wettability to molten metal due to carbonaceous materials. The refractory material used as a material for producing the carbonaceous brick is prepared by blending a carbon powder, a refractory aggregate, and a thermosetting resin serving as a binder, and mixing them.

[Problems to be solved by the invention]

However, carbon powder has poor mixing properties with refractory aggregates and thermosetting resins, so when compounding a large amount of carbon powder, it is necessary to increase the kneadability of the carbon powder by mixing a large amount of solvent. When a refractory material is prepared by blending such a large amount of solvent, a large amount of solvent is volatilized when the refractory material is formed to form a brick, and the porosity of the brick increases, and conversely, the molten metal becomes molten. However, the corrosion resistance, wear resistance, etc., of the steel sheet deteriorated. In addition, thermosetting resin used as a binder,
It is used in a liquid state to uniformly mix with a refractory aggregate having a large variation in particle size, and the refractory material is prepared as a kneaded material having a high viscosity. Therefore, if air is mixed into the refractory material during kneading during blending, it is difficult to remove the air, and there is a possibility that this air may be mixed when forming bricks. If air is mixed during molding in this way, when the molding pressure is applied, the air is compressed, but when the molding pressure is released, the air returns to the original volume, which may cause cracks in the bricks. The cracks may be enlarged during heating drying and curing, and may not be used as bricks. In addition, since the thermosetting resin is in a liquid state, during drying or hardening after molding into brick, the solvent or monomer etc. is volatilized and cracks occur, or in some cases explosion occurs due to rapid gas generation. There was also a risk of doing so. The present invention has been made in view of the above points, it is possible to uniformly blend carbonaceous powder without using a large amount of a solvent, and it is not necessary to use a liquid thing as a thermosetting resin binder. It is an object of the present invention to provide a refractory material capable of uniformly mixing an aggregate.

[Means for Solving the Problems]

The refractory material according to the present invention is a self-curing carbon powder and a self-curing carbon powder compacted with a thermosetting resin binder, and a self-curing refractory aggregate in which a refractory aggregate is combined with a thermosetting resin binder. The self-curing carbon powder and the self-curing refractory aggregate particles are characterized in that the content of the thermosetting resin binder is different, and the present invention is described in detail below. explain. The self-curing carbon powder particles are obtained by consolidating the carbon powder with a thermosetting resin as a binder, that is, by coating the carbon powder particles thinly with the thermosetting resin and aggregating through the thermosetting resin. It is prepared by solidifying carbon powder to obtain a solid powder. Here, as the carbon powder, any carbonaceous powder that can be generally used, for example, natural graphite, artificial graphite, carbon black, coke powder, charcoal powder, chaff charcoal, etc. can be used. These may be used alone or in combination of two or more. The particle size of the carbon powder is not particularly limited, but is preferably about 1 to 200 μm. The thermosetting resin used as the binder is not particularly limited, but a thermosetting resin which is cured by heating or the like, that is, a thermosetting resin having a self-curing property in a semi-cured state (so-called B-stage state) is used. Among them, a phenol resin, a melamine resin, a furan resin and the like are preferable among the thermosetting resins. In preparing the self-curing carbon powder, the carbon powder and the thermosetting resin are charged into a kneader such as a pressure kneader, kneaded with a solvent such as water or alcohol, and then the kneaded material is kneaded. The extruded product is put into an extruder, extruded while being further kneaded, and the extruded product is dried and crushed. Further, when preparing the self-curing carbon powder, the thermosetting resin can be attached to the surface of the carbon powder at the same time as preparing the initial condensate of the thermosetting resin. This was filed by the present applicant in Japanese Patent Application No. 61-
For example, in preparing an initial condensate of a phenolic resin, a phenol and an aldehyde are reacted in a reaction vessel while mixing with a carbon powder in the presence of a catalyst. The phenol resin is uniformly adhered to the surface of the powder, and the phenol resin is separated by filtration and dried to obtain a self-hardening carbon powder as a spherical powder. For melamine resin and furan resin, self-hardening carbon powder can be obtained in the same manner as in this method. In the case of melamine resin, a self-hardening carbon powder can be obtained as a spherical powder like a phenol resin, but in the case of a furan resin, generally spherical powder cannot be prepared. Therefore, it is used after freeze-drying. Carbon powder, particularly graphite, generally has poor wettability with a resin.When preparing a self-curing carbon powder by kneading a carbon powder and a resin with a kneader as in the former method, the carbon powder is uniformly dispersed. It is difficult to mix a large amount of carbon powder together with the carbon powder, but as in the latter method, the carbon powder is mixed at the same time as the thermosetting resin is synthesized to prepare self-curing carbon powder granules If you do, there is no such problem,
It is possible to easily prepare a self-hardening carbon powder in which carbon powder is uniformly dispersed and a large amount of carbon powder is blended. Therefore, in the present invention, the method for preparing the self-curing carbon powder is not particularly limited, but the latter method is more preferable. In preparing the self-hardening carbon powder as described above, it is preferable that the carbon powder be contained in an amount of 30% by weight or more. The upper limit of the amount of the carbon powder is not particularly set, but it is possible to mix the carbon powder up to about 99% by weight. If the carbon powder content is less than 30% by weight, the effect of reducing the wetting with the molten metal by mixing the carbon powder becomes insufficient, and if the carbon powder content is less than 30% by weight, the content of the thermosetting resin is reduced. Becomes 70% by weight or more,
A gas component generated by carbonization of the thermosetting resin when the brick is fired may increase the porosity of the brick and reduce the durability. Further, the size of the self-hardening carbon powder is not particularly limited, but is preferably in the range of about 5 to 2000 μm. The self-hardening carbon powder may be mixed with powder such as alumina and magnesia, if necessary, in addition to the carbon powder. A material or the like can be added. The self-curing refractory aggregate particles are prepared as solid fluid particles by compounding the refractory aggregate and a thermosetting resin binder. Here, as the refractory aggregate, magnesia, maguro, dromag, zircon, spinel, silica sand and the like can be used, and it is not particularly limited, but the particle size is preferably about 100 μm to 10 mm. The thermosetting resin used as the binder for the self-curing refractory aggregate particles is also not particularly limited, but is cured by heating or the like in the same manner as the binder for the self-curing carbon powder, that is, the self-curing property. A thermosetting resin having a semi-cured state is used, and a phenol resin, a melamine resin, a furan resin, or the like is preferable as in the binder of the self-curing carbon powder. The self-curing refractory aggregate particles may be prepared by mixing with a thermosetting resin binder and drying and pulverizing, but the surface of the refractory aggregate is coated with a thermosetting resin, and the form of resin-coated particles is used. It is preferable to use it after preparing it. In preparing the self-curing refractory aggregate particles by coating the refractory aggregate with a thermosetting resin binder, a dry hot coating method, a cold coating method, a semi-hot coating method,
It can be performed by a powdered solvent method or the like. In the dry hot coating method, the solid resin is added to the heated refractory aggregate, mixed, heated by sand to melt the solid resin, wet the surface of the sand with the molten resin and coated, and then hold the mixture. This is a method of obtaining a self-hardening refractory aggregate particle which is cooled while being cooled and is granular. Cold coating method
In this method, a resin is dissolved in a solvent such as methanol to form a liquid, which is added to the refractory aggregate, mixed, and then the solvent is volatilized to obtain self-hardening refractory aggregate particles. The semi-hot coating method uses a resin dissolved in
In this method, self-hardening refractory aggregate particles are obtained by adding and mixing to a refractory aggregate heated to about ° C. The powder solvent method is a method of pulverizing a solid resin, adding the pulverized resin to a refractory aggregate, further adding a solvent such as methanol, and mixing the resulting mixture to obtain self-curing refractory aggregate particles. In any of the methods described above, granulated and free-flowing self-curing refractory aggregate particles can be obtained, but a dry hot coating method is preferred in terms of workability and the like. In addition, various kinds of coupling agents such as a curing agent, other silane coupling agents for making the refractory aggregate and the resin compatible with each other as necessary in the mixing for preparing the self-curing refractory aggregate particles, and stearic acid. Bones such as calcium can be added. The size of the self-curing refractory aggregate thus prepared is not particularly limited, but is preferably in the range of about 100 μm to 10 mm. Further, in the self-curing refractory aggregate particles, the content of the thermosetting resin binder is not particularly limited, 1.
It is preferable to adjust so as to be contained in the range of 0 to 10% by weight. Since the self-curing carbon powder and the self-curing refractory aggregate particles prepared as described above are both solid particles, they can be mixed uniformly at an arbitrary ratio according to the purpose. Thus, the refractory material according to the present invention can be prepared. In such mixing, since the carbon powder is prepared as a self-curing carbon powder solidified by a thermosetting resin binder, the carbon powder is scattered during the mixing, thereby deteriorating the working environment. It can prevent such a thing, and can prepare a high refractory material with a high carbon powder content without the need to mix a large amount of solvent as in the case of directly blending carbon powder. It is. The refractory material prepared by mixing the self-hardening carbon powder and the self-hardening refractory aggregate particles in this manner is filled in a mold, tamped, or molded by pressing, and further, The brick can be formed by drying and curing in a furnace, and the brick can be cured or fired by the heat of the molten metal at the time of use. At this time, if necessary, a small amount of a lubricant such as water, ethylene glycol, oil or the like may be mixed with the refractory material to form a semi-dry or wet state, and the brick may be molded and hardened in the same manner as described above. Thus, a brick prepared using the refractory material according to the present invention can reduce the wettability with the molten metal because carbon powder is blended, and can enhance corrosion resistance and wear resistance. It is. Further, since it is not necessary to mix a large amount of solvent in the refractory material, there is no possibility that the porosity of the brick is increased due to the volatilization of the solvent and the corrosion resistance, abrasion resistance and the like are reduced. The thermosetting resin binder is contained in the self-hardening carbon powder and the self-hardening refractory aggregate,
Since it is not necessary to mix a liquid thermosetting resin binder, such as when a refractory material is prepared as a highly viscous kneaded material by mixing a liquid thermosetting resin binder,
When air is mixed in, it does not become difficult to come out, and there is no danger of cracking due to air being mixed into bricks, and drying and hardening after molding into bricks as in the case of liquid thermosetting resin In this case, there is no danger that the solvent, monomer or the like volatilizes to cause cracks, or explosion occurs due to rapid generation of gas. Here, in the present invention, the content of the thermosetting resin binder of the self-hardening carbon powder and the self-hardening refractory aggregate is not the same, and is adjusted so as to be different in both. Things. When the content of the thermosetting resin binder between the self-hardening carbon powder and the self-hardening refractory aggregate particles is made different as described above, uneven sea-island due to the difference in the amount of the binder in the formed bricks. A pattern is generated, and the portions having different amounts of binder differ in both strength and thermal expansion. And if the entire brick is molded with a uniform binder amount, if cracks occur, the cracks are likely to propagate from one end to the other and become large. It is possible to prevent the propagation of cracks from stopping at the boundary between different portions and prevent the cracks from propagating to the ends and becoming large. If the crack propagates from one end to the other and forms, the brick will be damaged by the crack and the molten metal will flow out, which is very dangerous, but the self-hardening carbon powder and the self-hardening refractory By adjusting the content of the thermosetting resin binder in the aggregate particles to be different, such a situation can be effectively prevented. Because the carbon powder has a larger specific surface area than the refractory aggregate, the content of the thermosetting resin binder is generally higher in the self-hardening carbon powder granules than in the self-hardening refractory aggregate particles. In order to effectively reduce the propagation of cracks as described above, the difference in the binder content is preferably 5% by weight or more.

【Example】

The invention will now be illustrated by way of examples. <Production Example 1 of Self-Curing Carbon Granules> A reaction vessel was charged with 770 parts by weight of phenol, 1328 parts by weight of 37% formalin, and 80 parts by weight of hexamethylenetetramine, and further, flaky graphite powder having an average particle size of 5 μm. 1362
90 parts by weight, 60 minutes while mixing and stirring
The reaction was continued for 3 hours. This was cooled, filtered and dried to obtain a spherical self-hardening carbon powder. This self-hardening carbon powder had an average particle diameter of 130 μm and a graphite powder content of 65% by weight. <Production Example 2 of Self-Curable Carbon Powder> 742 parts by weight of flaky graphite powder having an average particle size of 5 μm was placed in a pressure kneader, and 615 parts by weight of a 65% methanol solution of a solid resol type phenol resin was added thereto. This was kneaded for 30 minutes. After the kneading, the mixture was air-dried to disperse methanol, then placed in a drier set at 45 ° C., dried for 2 hours, and further pulverized by a coarse pulverizer to obtain self-hardening carbon powder particles. This self-hardening carbon powder has a particle size of 1 mm
It was under, and the content of graphite powder was 65% by weight. <Production Example 1 of Self-Curing Refractory Aggregate Particles> 1000 parts by weight of electrofused magnesia having an average particle size of 200 μm was heated to 160 ° C. or more in a heating furnace, and the mixture was charged into a mixer.
Adjusted to 50 to 160 ° C., at the same time as starting kneading with a mixer, 30 parts by weight of a solid novolak type phenolic resin was added, and then 60 seconds later, 15 parts by weight of water and 4.5 parts by weight of hexamethylenetetramine were added, 30 seconds after confirming the collapse, 1 part by weight of calcium stearate is added,
Then, after 30 seconds, the self-hardening refractory aggregate particles in which the surface of the refractory aggregate was coated with a phenol resin were obtained. The self-curing refractory aggregate particles had an average particle size of 210 μm and a content of electrofused magnesia of 96.6% by weight. <Production Example 2 of Self-Curing Refractory Aggregate Particles> In the same manner as in Production Example 1 above, except that futurary silica sand having an average particle size of 173 μ was used instead of electrofused magnesia, the average particle size was 180 μm. Thus, self-hardening refractory aggregate particles having a silica sand content of 96.6% by weight were obtained. Examples 1-1 to 1-3 <Production Example 1 of Self-Curing Carbon Powder>
The same as that obtained in Production Example 1> of self-curing refractory aggregate
Refractory materials were prepared by mixing at the ratios shown in the table. 150 g of this refractory material was weighed, filled into a mold having a cavity having a diameter of 45 mmφ, and subjected to pressure molding at 200 kgf / cm ² . This molded product was placed in a blow dryer set at 150 ° C. in advance, dried and cured for 2 hours, cooled once, placed again in a blow dryer set at 250 ° C., after-cured for 2 hours, and tested. I got a brick for it. The test piece thus obtained was measured for bulk specific gravity. Comparative Example 1 Self-curing refractory aggregate particles were not blended, and only the self-curing carbon powder was used. Thereafter, a brick for a test piece was prepared in the same manner as in "Examples 1-1 to 1-3". Obtained. Conventional Example 1 300 parts by weight of flaky graphite powder having an average particle size of 5 μm and 700 g of electrofused magnesia having an average particle size of 200 μm were put into a kneader.
Furthermore, a liquid novolak type phenol resin containing 30% by weight of ethylene glycol (having a viscosity of 15.5 Pa ·
35 parts by weight of s) and 5 parts by weight of hexamethylenetetramine as a curing agent were added and mixed for 30 minutes. The resulting composition was a kneaded material that adhered to the hands. This product was weighed and weighed at 150 parts by weight.
In the same manner as in "-3", molding, drying and curing were performed to obtain a brick for a test piece. Examples 2-1 to 2-5 <Production Example 1 of Self-Curing Carbon Powder>
The same as that obtained in Production Example 2> of self-curing refractory aggregate
The mixture was mixed for 2 minutes using a universal mixer at the ratios shown in the table, and water was added in the amount shown in Table 2 and mixed for 5 minutes to prepare a refractory material. The obtained refractory material hardly adhered to the hand even when grasped by hand. 150 g of this refractory material was weighed, placed in a mold having a diameter of 45 mmφ, and pressed to a height of 55 mm. This was dried and cured in the same manner as in "Examples 1-1 to 1-3" to obtain a brick for a test piece. Comparative Examples 2-1 and 2-2 Only the self-curing carbon particles were used without blending the self-curing refractory aggregate particles (Comparative Example 2-1) or without blending the self-curing carbon particles. Using only self-hardening refractory aggregate particles (Comparative Example 2
-2) Then, bricks for test pieces were obtained in the same manner as in "Examples 2-1 to 2-5". Conventional Example 2 Using the compound obtained in Conventional Example 1, "Examples 2-1 to 2-
In the same manner as in 5), the resin was molded to a height of 55 mm, and dried and cured in the same manner to obtain a brick for a test piece. Examples 3-1 to 3-5 <Production Example 2 of Self-Curable Carbon Granules>
The same as that obtained in Production Example 2> of self-hardening refractory aggregate
Mix for 2 minutes with a universal mixer at the ratios shown in the table, and add ethylene glycol in the amount shown in Table 2 to obtain 5
Mix for minutes to prepare the refractory material. The obtained refractory material hardly adhered to the hand even when grasped by hand.
Then, using this refractory material, "Examples 2-1 to 2-
In the same manner as in 5), the resin was molded to a height of 55 mm, and dried and cured in the same manner to obtain a brick for a test piece. Comparative Examples 3-1 and 3-2 Only the self-curing carbon powder was used without blending the self-curing refractory aggregate particles (Comparative Example 3-1), or the self-curing carbon powder was not blended. Using only self-hardening refractory aggregate particles (Comparative Example 3
-2) Then, bricks for test pieces were obtained in the same manner as in "Examples 3-1 to 3-5". The linear expansion coefficient, bulk specific gravity, and compressive strength of each test piece brick obtained by after-cueing at 250 ° C. as described above were measured. In addition, bricks for each test piece must be
It was placed in an electric furnace set at 1000 ° C. for 5 minutes, fired, taken out, visually checked for cracks, and immediately put into water to be rapidly cooled. The quenched test piece was taken out, and the spalling resistance was observed by visually checking for cracks.

【The invention's effect】

As described above, the present invention relates to a self-curing carbon powder particle in which carbon powder is consolidated with a thermosetting resin binder, and a self-curing refractory aggregate particle in which refractory aggregate is combined with a thermosetting resin binder. Since the carbon powder is prepared as a self-curing carbon powder solidified by a thermosetting resin binder, as in the case of directly blending the carbon powder, The carbon powder can be uniformly mixed without the need to mix a large amount of solvent, and the molded brick does not become porous due to volatilization of the solvent, and the corrosion resistance and abrasion resistance to the molten metal can be increased. Since the refractory aggregate is prepared as self-curing refractory aggregate particles combined with a thermosetting resin binder, the refractory aggregate can be used without the need to mix a liquid thermosetting resin binder. Can be blended together, as in the case of blending a liquid thermosetting resin binder to prepare a refractory material as a highly viscous kneaded material, it does not become difficult to remove when air is mixed in, This eliminates the risk of cracking due to the incorporation of air.
In addition, since the content of the thermosetting resin binder is different between the self-hardening carbon powder and the self-hardening refractory aggregate, the unevenness due to the difference in the amount of the binder in the molded brick is not uniform.
Even if an island pattern occurs, even if a crack occurs in the brick, the propagation of the crack stops at the boundary of the portion with a different binder amount and can prevent the crack from spreading to the end and becoming large. It is.

Claims (1)

(57) [Claims] 1. A self-curing carbon powder body in which carbon powder is consolidated with a thermosetting resin binder, and a self-curing refractory aggregate particle in which a refractory aggregate is combined with a thermosetting resin binder. A material for refractories, characterized in that the content of the thermosetting resin binder is different between the self-hardening carbon powder and the self-hardening refractory aggregate.