JP2012082117A - Method for manufacturing monolithic fireproof kneaded material, and refractory construction object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of kneading uniformly by preventing aggregation of fireproof powder and grain, and obtaining an monolithic fireproof kneaded material having characteristics excellent in strength development, fluidity or the like, and to provide a refractory construction object formed by curing the obtained monolithic fireproof kneaded material.SOLUTION: In the method for manufacturing a monolithic fireproof kneaded material by kneading fireproof powder and grain containing ultrafine powder whose average particle size is ≤10 μm with a dispersant, at least a part of the ultrafine powder and the dispersant are added into water to acquire an ultrafine powder dispersion whose percentage by mass of ultrafine powder/(ultrafine powder plus water) is ≥5 mass% and ≤85 mass%, and the ultrafine powder dispersion and a residue of the fireproof powder and grain are kneaded together. The refractory construction object is obtained by pouring the obtained monolithic fireproof kneaded material into a prescribed form and by curing it.

Description

  The present invention relates to a method for producing an amorphous refractory kneaded material and a refractory construction body, and more specifically, to obtain a kneaded material of an amorphous refractory that is uniformly kneaded while preventing aggregation of the refractory powder particles. The present invention relates to a method for producing an amorphous refractory kneaded product, and a refractory construction body comprising the obtained amorphous refractory kneaded product.

  Refractories are indispensable in the field of handling high-temperature materials such as iron and steel manufacturing, and high durability of refractories is necessary for stabilizing production in various fields and reducing costs. In particular, amorphous refractories that are poured into a formwork and hardened or sprayed onto construction objects that require fire resistance are widely used because they are more versatile than regular refractories. It is extremely important to improve the durability and workability of the regular refractories.

  The amorphous refractory is generally obtained by first kneading a refractory powder such as alumina or magnesia together with water to obtain a kneaded product. This refractory powder has a particle size exceeding a few millimeters to an ultrafine powder of less than 1 μm. For example, in the case of sintered alumina, which is a typical example of a refractory powder, coarse particles having a particle diameter of 1 mm or more, Refractory raw materials having various particle sizes such as medium particles having a particle size of 75 μm or more and fine particles having a particle size of less than 75 μm are commercially available. Usually, the minimum sieve size that can be sieved is 45 μm, and ultrafine powders such as calcined alumina having an average particle size of 10 μm are commercially available. And according to the objective of making it an aggregate and improving the fluidity | liquidity of an amorphous refractory kneaded material, the mixture ratio of these refractory raw materials is determined, and it is set as a refractory powder granule.

  By the way, when obtaining an irregular refractory kneaded material, it is ideal that each of the particles constituting the refractory powder is dispersed as discrete primary particles. However, since the refractory powder particles include particles having a very small particle size such as fine particles and ultrafine particles, they are difficult to mix with water and easily aggregate to form secondary particles. Once secondary particles are formed, crushing to primary particles is not easy. Thus, a dispersing agent (also called a peptizer or a water reducing agent) that repels particles and prevents aggregation can be mixed with the refractory powder to make it difficult to form secondary particles. If the amount of the dispersant added increases, problems such as a decrease in the curability of the amorphous refractory kneaded product occur, and therefore the amount of the dispersant cannot be increased unnecessarily. Therefore, it is difficult to completely prevent the formation of secondary particles, and when actually obtaining an irregular refractory kneaded material, it is the fact that a large amount of fine and ultrafine powder is blended in anticipation of the inability to crush. It is.

  In such a situation, for example, a first refractory powder obtained by adding an ultrafine powder having a particle size of 10 μm or less to a powder having a particle size of 45 μm or less, and a second refractory powder comprising a powder having a coarser particle diameter than these. First, the first refractory powder is mixed while applying shearing force with a mixer or the like to loosen the secondary particles, and this is added to the second refractory powder and mixed. Thus, a method has been proposed in which the proportion of secondary particles formed by primary particles having a particle size of less than 45 μm is reduced (see Patent Document 1). Also proposed is a method of improving the dispersibility of fine powder by kneading ultrafine powder with an average particle size of 10 μm or less, a dispersant, and water into a slurry, adding this to the remainder of the refractory powder and kneading. (See Patent Document 2). However, there is still room for improvement in order to obtain an ideal amorphous refractory kneaded material in which the refractory powder particles are uniformly dispersed without being agglomerated.

JP 2008-156143 A JP-A-8-239276

  When the present inventors examined in detail about the method of the prior art mentioned above, when the former method (patent document 1) proposed, for example, is used, it is actually a grain in the first refractory granular material. Due to the presence of a powder having a diameter of 45 μm or less, it is difficult to proceed with the pulverization of the ultrafine powder having a particle diameter of 10 μm or less, and the ultrafine powder having a particle diameter of 10 μm or less is caught in a powder having a particle diameter of 45 μm or less. It was found that would form. On the other hand, in the latter method (Patent Document 2), about 5 to 6 wt% of kneading water is added to the outer periphery of about 15 parts of ultrafine powder and 0.03 to 0.1 part of a dispersant to form a slurry. Although it has been obtained (see Table 1 of Patent Document 2), the amount of the dispersing agent is excessively increased by this method, which is not suitable for economic efficiency, and there is a risk of poor curing of the refractory.

  Therefore, the present inventors have intensively studied about means for obtaining an irregular refractory kneaded material by uniformly kneading, preventing aggregation of refractory powder particles, particularly preventing aggregation of ultrafine powder having an average particle size of 10 μm or less. As a result, at least a part of the ultrafine powder and a dispersing agent are added to water and dispersed in advance to prepare an ultrafine powder dispersion, and this is added to the remainder of the refractory powder and kneaded. The present invention has been completed.

  Therefore, an object of the present invention is to provide a method capable of obtaining an amorphous refractory kneaded material that can be uniformly kneaded while preventing aggregation of the refractory powder and is excellent in properties such as strength development and fluidity. There is to do.

  Further, another object of the present invention is to cure the amorphous refractory kneaded material obtained above, which is economical, free from curing trouble, dense, high strength, and highly corrosion resistant refractory construction. To provide a body.

  That is, the present invention is a method for producing an amorphous refractory kneaded material by kneading a refractory powder containing an ultrafine powder having an average particle size of 10 μm or less and a dispersant, and comprising at least part of the ultrafine powder. And a dispersant are added to water to obtain an ultrafine powder dispersion having a mass percentage of ultrafine powder / (ultrafine powder + water) of 5% by mass or more and 85% by mass or less, and the ultrafine powder dispersion and the fire resistance. This is a method for producing an irregular refractory kneaded product, characterized by kneading the remainder of the powder and granule.

  Moreover, this invention is the refractory construction body which poured the amorphous refractory kneaded material obtained by the said method into the predetermined formwork, and was hardened.

  In the present invention, a refractory granular material containing an ultrafine powder having an average particle size of 10 μm or less is used. When this ultrafine powder is blended, the flowability of the irregular refractory kneaded product can be increased, and it can be easily filled into the mold, and the bubbles generated when it is poured can easily float and escape. Can be improved. Moreover, there exists an effect which raises the intensity | strength of the construction body obtained by hardening, or improves a durability by making a construction body dense. These effects are strongly manifested when the ultrafine powder is a primary particle, but the effect is lost when it is agglomerated to secondary particles. Therefore, the ultrafine powder is uniformly dispersed in the amorphous refractory kneaded product. And kneading. Here, the average particle diameter means a median diameter, and represents a particle diameter at which the mass cumulative value becomes 50% in the particle size distribution.

As the ultrafine powder having an average particle size of 10 μm or less, a powder generally used as a refractory material can be used. The types include, for example, alumina, silica, magnesia, titania, zirconia, yttria, SiC, B ₄ C, C, various cements, oxides such as aluminum, silicon, magnesium, carbonates, water Japanese, hydroxides, borides or carbides, as well as those made of metals such as Al, Si, etc. can be exemplified, and in addition, workability, construction body characteristics, etc. can be added as refractory powders. Including substances that can improve. Among these, in consideration of availability, calcined alumina, ultrafine silica (also referred to as silica flour, volatile silica, microsilica, etc.), spinel, and the like can be cited as suitable ultrafine powders.

  As for the refractory powder other than the ultrafine powder, a general refractory raw material can be used as in the case of the ultrafine powder, and the kind of refractory raw material as exemplified in the ultrafine powder can be used. Although they can be used, those having a particle size larger than the ultrafine powder are used. Preferably, sintered or fused alumina, sintered or fused magnesia, sintered or fused spinel, zircon, zirconia, meteorite, silica, chamotte, clay, wax, shale, bauxite, sillimanite, andalyu Carbon such as site, kayanite, mullite, alumina-zirconia, dolomite, SiC, graphite, etc. can be used, and coarse particles (for example, 1 mm or more), medium particles (also 75 μm or more), fine particles (also less than 75 μm), etc. It is preferable to mix appropriately so as to obtain an irregular refractory kneaded material according to the intended construction body while selecting those having different particle diameters. Specifically, alumina-silica, siliceous, alumina, alumina-magnesia, alumina-spinel, zirconia, zircon, semi-zircon, magnesia, magnesia-spinel, magnesia-C, alumina- What is necessary is just to determine the compounding composition of a refractory granular material including a particle size so that various amorphous refractory kneaded materials including C quality, alumina-SiC-C quality, etc. may be obtained.

  In producing an amorphous fire-resistant kneaded product, first, a part or all of the ultrafine powder and a dispersant are added to water to obtain an ultrafine powder dispersion in which the ultrafine powder is dispersed. At that time, the mass percentage of ultrafine powder / (ultrafine powder + water) (hereinafter referred to as dispersion concentration) is in the range of 5 mass% to 85 mass%, preferably 10 mass% to 50 mass%. Add ultrafine powder to If this mass percentage is less than 5% by mass, the effect of obtaining the ultrafine powder dispersion in advance and dispersing the ultrafine powder is not recognized, whereas if it exceeds 85% by mass, the ultrafine powder is precipitated, or It becomes impossible to sufficiently disperse the ultrafine powder, for example, it cannot be sufficiently pulverized. Therefore, the quality of the construction body may be slightly inferior compared with the case where the dispersion concentration is appropriate. Or an irregular-shaped refractory construction body may become denser more than necessary, an elastic modulus may rise, and it may become weak to a thermal shock. When using an emulsifier / disperser, if the dispersion concentration exceeds 50% by mass, the apparent viscosity or specific gravity of the dispersion is too high, and it becomes difficult to process with the disperser. In addition, when the ultrafine powder is contained in the refractory powder within the concentration range of the ultrafine dispersion, the whole may be used for forming the ultrafine dispersion, or only a part may be used. May be. Moreover, when the ultrafine powder of the quantity exceeding a density | concentration range is contained in a refractory granular material, the excess ultrafine powder should just be handled as the remainder of a refractory granular material.

  As the dispersant for forming the ultrafine powder dispersion, those generally used for producing an amorphous fireproof kneaded product can be used. For example, alkali metal phosphates such as sodium tripolyphosphate, sodium hexametaphosphate, sodium ultrapolyphosphate, and sodium acid hexametaphosphate, polycarboxylates such as sodium polycarboxylate, alkyl sulfonate, aromatic Examples thereof include sulfonate, sodium polyacrylate, sodium sulfonate, and the like, and one or more of these can be used. The concentration of the dispersant in the ultrafine powder dispersion is preferably 0.05% by mass or more and 0.6% by mass or less, more preferably 0.1% by mass, from the viewpoint of uniformly dispersing the ultrafine powder. The amount is preferably 0.6% by mass or less. In addition, a powdery thing may be used for a dispersing agent and a liquid thing may be used.

  In general, dispersants are not effective for all types of refractory powders. For example, an amorphous refractory mainly composed of alumina, which is currently mainstream, is kneaded using a dispersant having a high dispersion capacity with respect to alumina as a main component. On the other hand, in an alumina-magnesia-based amorphous refractory, generally, ultrafine silica is mainly added and kneaded as an ultrafine powder, but this ultrafine silica is well dispersed with a dispersant having a high effect on alumina. So far, ultrafine silica has not been able to obtain a relatively sufficient dispersion effect. Therefore, by forming the ultrafine powder dispersion in advance, at least a certain dispersion effect can be expected regardless of the type of the ultrafine powder, and in particular, the ultrafine powder dispersed in the ultrafine dispersion is an average. It can be said that the effect of using the ultrafine dispersion is sufficiently exhibited when the ultrafine silica having a particle size of 10 μm or less is included. That is, when the material of the amorphous refractory kneaded material is a material containing silica ultrafine powder such as alumina-magnesia, alumina-silica, alumina-SiC-C, for example, the silica ultrafine powder is as much as possible. A dispersion is desirable. Of course, it is desirable that the ultrafine alumina powder be a superfine powder dispersion as much as possible. That is, even when the ultrafine powder dispersed in the ultrafine powder dispersion is calcined alumina having an average particle size of 10 μm or less, the effect is sufficiently exhibited. Further, for example, two or more kinds may be dispersed so as to contain calcined alumina together with ultrafine silica.

  When dispersing ultrafine powder and dispersant in water, in addition to stirring by human power, a rotating stirrer that rotates a stirrer, a device that rotates, vibrates or swings, a device that stirs with bubbles Alternatively, an apparatus that can collide the liquid discharged from the nozzle and stir with the collision energy may be used. Preferably, an emulsifying disperser is used for finishing after using these apparatuses or alone. The emulsification disperser is mainly used in the fields of food production, paint / ink production, and the like, and is an apparatus for dispersing powder particles in a liquid. The emulsification disperser has, for example, a cup type, a cylindrical type, or a single or a plurality of stators having an uneven disk shape, and a cup type, a cylindrical type, or an uneven shape that is fitted or opposed to the stator with a narrow clearance. Since one or a plurality of disk-shaped rotors are provided and shear stress is generated between them, the ultrafine powder can be dispersed and crushed while applying a greater shearing force. Further, when obtaining the ultrafine powder dispersion, it is preferable to add the ultrafine powder after dissolving the dispersant in water, thereby reliably eliminating the possibility that the ultrafine powder aggregates. Even if the entire amount of the dispersant is not dissolved in water, it is considered that if a part of the dispersant is dissolved, it is considered that there is an effect of preventing aggregation of the ultrafine powder. Although fine powder may be added, it is preferable to add the ultrafine powder by dissolving the total amount of the dispersant in water.

  For kneading the ultrafine powder dispersion and the remainder of the refractory powder granules, those generally used for kneading when obtaining an amorphous refractory can be used. Specifically, flat mixers (mortar mixers, trade name vortex mixers, trade name turbo mixers, etc.), universal mixers, pot mixers, ribbon mixers, biaxial kneader mixers, trade names high function mixers, trade names omni mixers, products A name dicross mixer, a brand name Eirich mixer, etc. can be mentioned, but are not limited thereto. The irregular refractory kneaded material obtained by kneading can be poured into a mold or the like by, for example, a conventional method, and if necessary, shaken and molded, cured, and cured to obtain a construction body. Moreover, you may spray the obtained amorphous refractory kneaded material on a refractory object. The obtained construction body may be dried or sintered as necessary.

  In obtaining an amorphous refractory kneaded product, the mixing ratio of the ultrafine powder dispersion and the remainder of the refractory powder granules can be appropriately determined according to the intended use of the refractory construction body, its material, etc. As an index, it can be determined by the moisture content of the irregular refractory kneaded product and the dispersion concentration of the ultrafine powder dispersion. That is, the water content is determined by material design considering the required fluidity and necessary characteristics of the construction body in addition to the particle size blending of the whole amorphous refractory kneaded product and the properties of the dispersant. In general, the moisture content of the irregular refractory kneaded material is about 4 to 6% by mass as an outer shell, and this range can be used as a guide. Since it is better for the moisture content to be small in order to obtain a dense construction body, it is desirable to increase the dispersion concentration of the ultrafine powder dispersion. On the other hand, when thermal shock resistance is required, it is preferable to reduce the dispersion concentration of the ultrafine powder dispersion to increase the water content. As described above, when the concentration of the ultrafine powder dispersion is high, the construction body becomes vulnerable to thermal shock.For example, when obtaining an irregular refractory kneaded material that forms a refractory construction body used for the hot water contact part of a molten steel ladle. The dispersion concentration of the ultrafine powder dispersion is, for example, 30% by mass or less, and the remainder of the ultrafine powder is preferably kneaded according to the refractory powder. Further, when denseness is required as in a molten steel ladle tuyere, for example, it is preferably 30% by mass or more, and the remainder of the ultrafine powder is kneaded according to the refractory powder.

  In the present invention, since the ultrafine powder is uniformly dispersed in advance in the ultrafine powder dispersion, the amount of the dispersant used in the irregular refractory kneaded product can be suppressed to the minimum necessary, and preferably the irregular shape. The ratio of the dispersant in the refractory kneaded material is preferably 0.0025% by mass or more and 0.05% by mass or less, and more preferably 0.005% by mass or more and 0.04% by mass or less. This not only provides an economic advantage, but also prevents the refractory powder from agglomerating while suppressing the poor curing of the irregular refractory kneaded product and eliminating the risk of reducing the strength of the refractory construction body. Can be kneaded uniformly. In addition, in an irregular refractory kneaded material that forms a refractory construction body used for blast furnace slag, molten steel ladle, tundish, lance, etc., the proportion of ultrafine powder in the refractory powder is 1% by mass or more and 30% by mass. % Or less, preferably 3% by mass or more and 15% by mass or less, more preferably 5% by mass or more and 10% by mass or less. Since the ultrafine powder is uniformly dispersed in the ultrafine dispersion, the function of the ultrafine powder can be maximized, and the fluidity of the amorphous refractory kneaded material can be sufficiently ensured at the above blending ratio. A refractory construction body excellent in durability and strength can be obtained. In particular, since the refractory construction body obtained by the present invention has a denser structure that prevents the aggregation of ultrafine powder, it is generally said that the strength of the refractory construction body is said to decrease. It has excellent characteristics even in hot strength at room temperature or normal temperature strength after firing at the same temperature.

  According to the present invention, it is possible to uniformly knead agglomerates of refractory powder particles, and it is possible to obtain an amorphous refractory kneaded material excellent in properties such as strength development and fluidity. In particular, in the method for producing an irregular refractory kneaded product of the present invention, an ultrafine powder having an average particle size of 10 μm or less is dispersed in advance together with a dispersant to obtain an ultrafine powder dispersion. The function of the ultrafine powder and the dispersant can be exerted to the maximum without fear of forming secondary particles by covering with a diameter. In addition, the amorphous refractory kneaded product obtained by the present invention has good workability and is suitable for obtaining a refractory construction body excellent in strength and durability.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not restrict | limited to the following content.

[Ultrafine powder dispersion confirmation test]
A dispersion test solution was prepared by adding 1280 g of calcined alumina having a median diameter of 0.6 μm to 3000 g of an aqueous solution containing 0.1 mass% sodium hexametaphosphate. Here, the median diameter of calcined alumina is a particle diameter at which the cumulative curve of the particle size distribution expressed in mass is 50% by mass. First, the dispersion test liquid was stirred for 5 minutes with a rotary stirrer (twisted cruciform blade, outer diameter of blade 50 mm) at a rotation speed of 150 rpm, and then a laser diffraction particle size distribution analyzer (SALD-3000S manufactured by Shimadzu Corporation) When the median diameter of the calcined alumina in the dispersion test solution was examined with no ultrasonic dispersion, the median diameter was 2 μm.

  Next, the dispersion test liquid after stirring with this rotary type stirring device was passed once through an emulsifying disperser (MDN304, manufactured by Taiyo Kiko Co., Ltd.) having a rotational speed of 10000 rpm each having three pairs of rotors and stators, in the same manner as described above. When the median diameter of the calcined alumina was examined, the median diameter was 0.7 μm. In addition, the dispersion test liquid after stirring with the rotary type stirring device is separated from the emulsification disperser once in a device (HJP25005 made by Sugino Machine) that stirs the liquid sprayed from the fine nozzles arranged opposite to each other. Then, the median diameter of the calcined alumina was examined in the same manner as described above, and the median diameter was 0.7 μm. As a result of the above, the ultrafine powder in the dispersion test liquid can be pulverized to primary particles with a rotary stirrer, and the subsequent agglomeration can be prevented. It was confirmed that the ultrafine powder can be dispersed and crushed.

[Example 1]
As shown in Table 1, as the refractory granular material, sintered alumina (3 types of particle size 5 mm or less, 150 μm or less, 45 μm or less), sintered magnesia (particle size 75 to 45 μm), calcined alumina (2 types of median diameter 5 μm and 1 μm), ultra fine silica (median diameter 1 μm), and first type alumina cement (particle size 45 μm or less) are prepared, and sodium hexametaphosphate (powder) ) Was prepared, and an irregular refractory kneaded material according to Example 1 was produced as follows.

  First, with respect to 700 g of water (corresponding to 7% by mass with respect to the refractory powder), 170 g (calculated refractory powder) of calcined alumina having a median diameter of 5 μm and calcined alumina having a median diameter of 1 μm. And 3 g of the dispersing agent (corresponding to 0.03 mass% on the outer side of the refractory powder) at the same time, and this was used in the dispersion confirmation test. The mixture was stirred for 3 minutes with a rotary stirring device having the same rotational speed of 150 rpm to obtain an ultrafine powder dispersion. The mass percentage of “ultrafine powder / (ultrafine powder + water)” in the ultrafine powder dispersion is 32.6% by mass.

  Next, the remaining part of the refractory powder particles described in the column of powder particles in Table 1 was mixed by air for 1 minute using a universal kneader (25 AM-Qr manufactured by Dalton), and then the ultrafine powder obtained above The dispersion was added and kneaded for an additional 3 minutes to obtain an alumina amorphous refractory kneaded product. About the obtained amorphous fireproof kneaded material, the free flow and the tap flow were measured according to the procedure of the flow test of JIS-R2521. Moreover, the obtained irregular refractory kneaded material was poured into a mold and molded by shaking at 1.5 G for 1 minute. Then, after curing at room temperature for 24 hours, the frame was removed and dried at 110 ° C. for 24 hours, and the bulk specific gravity, porosity, and bending strength were measured. Among these, the bulk specific gravity and the porosity were measured according to JIS-R2205 using a 40 mm × 40 mm × 40 mm sample. The bending strength was measured with a span of 100 mm using a sample having a cross section of 40 mm × 40 mm and a length of 160 mm. About bending strength, the value after baking the sample after drying for 6 hours at 1000 degreeC was also measured. These results are shown in Table 1.

[Example 2]
In obtaining an ultrafine powder dispersion, first, 3 g of a dispersant was dissolved in 700 g of water using a rotary stirrer having a rotation speed of 150 rpm, and then calcined alumina having a median diameter of 5 μm and calcined alumina having a median diameter of 1 μm. Was added in the same manner as in Example 1 except that the mixture was further stirred for 3 minutes with a rotary stirrer having a rotational speed of 150 rpm, to produce an alumina refractory kneaded material according to Example 2. The obtained amorphous fireproof kneaded material was measured in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
The ultrafine powder dispersion obtained in Example 2 was further processed once at a rotational speed of 10,000 rpm using the same emulsification disperser used in the above dispersion confirmation test to prepare an ultrafine powder dispersion according to Example 3. did. An alumina amorphous refractory kneaded material according to Example 3 was obtained in the same manner as Example 2 except that this ultrafine powder dispersion was used. The obtained amorphous fireproof kneaded material was measured in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
In obtaining an ultrafine powder dispersion, first, 2.5 g of a dispersant was dissolved in 600 g of water using a rotary stirrer having a rotation speed of 150 rpm, and then 100 g of ultrafine silica having a median diameter of 1 μm was added. The mixture was stirred for 3 minutes with a rotary stirrer having a rotational speed of 150 rpm. Subsequently, this stirred liquid was further processed once at a rotational speed of 10,000 rpm using an emulsifying disperser to prepare an ultrafine powder dispersion of Example 4. Next, using a universal kneader, the remaining portion of the refractory powder particles listed in the column of powder particles in Table 1 is mixed by air for 1 minute, and then the obtained ultrafine powder dispersion is added and kneaded for 3 minutes. Thus, an alumina-magnesia amorphous refractory kneaded material according to Example 4 was obtained. The obtained amorphous fireproof kneaded material was measured in the same manner as in Example 1. The results are shown in Table 1.

[Example 5]
In obtaining an ultrafine powder dispersion, first, 2.5 g of a dispersant was dissolved in 600 g of water using a rotary stirrer having a rotation speed of 150 rpm, and then calcined alumina having a median diameter of 5 μm and temporary median having a median diameter of 1 μm. 120 g of each baked alumina and 100 g of ultrafine silica having a median diameter of 1 μm were added, and the mixture was further stirred for 3 minutes with a rotary stirrer having a rotational speed of 150 rpm. Subsequently, this stirred liquid was further processed once at a rotational speed of 10,000 rpm using an emulsifying disperser to prepare an ultrafine powder dispersion of Example 5. Next, using a universal kneader, the remaining portion of the refractory powder particles listed in the column of powder particles in Table 1 is mixed by air for 1 minute, and then the obtained ultrafine powder dispersion is added and kneaded for 3 minutes. Thus, an alumina-magnesia amorphous refractory kneaded material according to Example 5 was obtained. The obtained amorphous fireproof kneaded material was measured in the same manner as in Example 1. The results are shown in Table 1.

[Example 6]
In obtaining an ultrafine powder dispersion, first, 2.5 g of a dispersant was dissolved in 600 g of water using a rotary stirrer having a rotation speed of 150 rpm, then 300 g of calcined alumina having a median diameter of 5 μm and a median diameter of 1 μm. 200 g of the calcined alumina and 100 g of ultrafine silica having a median diameter of 1 μm were added, and the mixture was further stirred for 3 minutes with a rotary stirrer having a rotation speed of 150 rpm to prepare an ultrafine dispersion of Example 6. Next, using a universal kneader, the remaining portion of the refractory powder particles listed in the column of powder particles in Table 1 is mixed by air for 1 minute, and then the obtained ultrafine powder dispersion is added and kneaded for 3 minutes. Thus, an alumina-magnesia amorphous refractory kneaded material according to Example 6 was obtained. The obtained amorphous fireproof kneaded material was measured in the same manner as in Example 1. The results are shown in Table 1.

[Example 7]
In obtaining an ultrafine powder dispersion, first, 3 g of a dispersant was dissolved in 600 g of water using a rotary stirrer having a rotational speed of 150 rpm, and then 900 g of calcined alumina having a median diameter of 5 μm and a temporary media having a median diameter of 1 μm were obtained. 600 g of calcined alumina was added, and the mixture was further stirred for 3 minutes with a rotary stirrer having a rotation speed of 150 rpm to prepare an ultrafine powder dispersion of Example 7. Next, using a universal kneader, the remaining portion of the refractory powder particles listed in the column of powder particles in Table 1 is mixed by air for 1 minute, and then the obtained ultrafine powder dispersion is added and kneaded for 3 minutes. Thus, an amorphous amorphous refractory kneaded material according to Example 7 was obtained. The obtained amorphous fireproof kneaded material was measured in the same manner as in Example 1. The results are shown in Table 1.

[Example 8]
In obtaining an ultrafine powder dispersion, first, 3 g of a dispersant was dissolved in 600 g of water using a rotary stirrer having a rotational speed of 150 rpm, and then 1200 g of calcined alumina having a median diameter of 5 μm and temporary media having a median diameter of 1 μm were obtained. 800 g of baked alumina was added, and the mixture was further stirred for 3 minutes with a rotary stirrer having a rotation speed of 150 rpm to prepare an ultrafine powder dispersion of Example 8. Next, using a universal kneader, the remaining portion of the refractory powder particles listed in the column of powder particles in Table 1 is mixed by air for 1 minute, and then the obtained ultrafine powder dispersion is added and kneaded for 3 minutes. Thus, an amorphous amorphous refractory kneaded material according to Example 7 was obtained. The obtained amorphous fireproof kneaded material was measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Examples 1-4]
Comparative Examples 1, 3, and 4 are examples in which all raw materials were kneaded with a universal kneader. First, the refractory powder granules and the dispersant shown in Table 2 were mixed by air using a universal kneader for 1 minute, and then water was added and kneaded for 3 minutes to produce an amorphous refractory kneaded product. . Comparative Example 2 is an example in which pre-kneading was performed by adding sintered alumina (particle size of 45 μm or less) and alumina cement (particle size of 45 μm or less) together with calcined alumina. First, a dispersing agent was added to these and air-mixed for 1 minute in a universal kneader, and then water was added and kneaded for another 3 minutes. When adding water and kneading, the number of rotations of the stirring bar was doubled. The obtained kneaded liquid was added to the remainder of the refractory particles shown in Table 1 and kneaded for 3 minutes at normal rotation (peripheral speed of about 1 m / s) to produce an amorphous refractory kneaded product. The irregular refractory kneaded materials obtained in Comparative Examples 1 to 4 were measured in the same manner as in Example 1. The results are shown in Table 2. In the pre-kneading in Comparative Example 2, sintered alumina and alumina cement exceeding 10 μm were included and the concentration was high, so that the rotary stirrer used in the examples could not be used.

  About the result of the said Example and a comparative example, when the Examples 1-3 which have the same composition composition of a refractory powder granule and the comparative example 1-2 which has obtained the same alumina non-flammable refractory kneaded material are compared, about a dispersing agent is about. In spite of the inclusion of 3 times, all of the amorphous refractory kneaded materials of Examples 1 to 3 were excellent in fluidity and showed high bending strength after curing. Specifically, the irregular refractory kneaded materials of Examples 1 to 3 have a higher flow than those of Comparative Examples 1 to 2, and have a low porosity and high strength, and are excellent when used as a construction body. It was confirmed. The same can be said when Examples 4 to 6 and Comparative Example 3 in which an alumina-magnesia amorphous refractory kneaded material is obtained are compared. In Examples 4 to 6, the amount of the dispersant added was 1/4 compared to Comparative Example 3, but the amorphous refractory kneaded material of Examples 4 to 6 had a higher flow than that of Comparative Example 3. In addition, it has been confirmed that it has a high bulk specific gravity, a low porosity and a high strength, and is excellent when used as a construction body. In particular, when the results of Examples 4 to 6 and Comparative Example 3 are compared, the effectiveness of the ultrafine powder dispersion in which ultrafine silica is dispersed is obvious at a glance, and the degree of dispersion of the ultrafine powder having an average particle size of 10 μm or less. Can greatly affect the quality of the irregular refractory kneaded material. The same applies to Examples 7 to 8 and Comparative Example 4. That is, compared with the comparative example 4, Examples 7-8 were high flow, high bulk specific gravity, low porosity, and high intensity | strength. However, when compared with Example 7, Example 8 had slightly low bulk specific gravity, high porosity, and low strength. This is thought to be because the concentration of the ultrafine powder dispersion was as high as 80%.

Claims (8)

  A method for producing an amorphous refractory kneaded material by kneading a refractory powder containing ultrafine powder having an average particle size of 10 μm or less and a dispersant, wherein at least a part of the ultrafine powder and the dispersant are mixed with water. In addition, an ultrafine powder dispersion having a mass percentage of ultrafine powder / (ultrafine powder + water) of 5 mass% to 85 mass% is obtained, and the ultrafine powder dispersion and the remainder of the refractory powder are obtained. A method for producing an irregular refractory kneaded material, characterized by kneading.   The method for producing an amorphous refractory kneaded product according to claim 1, wherein after dissolving the dispersant in water, at least a part of the ultrafine powder is added to obtain an ultrafine powder dispersion.   The method for producing an amorphous refractory kneaded product according to claim 1 or 2, wherein the concentration of the dispersant in the ultrafine powder dispersion is 0.05% by mass or more and 0.6% by mass or less.   The method for producing an amorphous refractory kneaded product according to any one of claims 1 to 3, wherein an ultrafine powder dispersion is obtained using an emulsifying disperser.   The method for producing an amorphous refractory kneaded product according to any one of claims 1 to 4, wherein a ratio of the ultrafine powder in the refractory powder is 1% by mass or more and 30% by mass or less.   The method for producing an amorphous refractory kneaded product according to any one of claims 1 to 5, wherein the proportion of the dispersant in the amorphous refractory kneaded product is 0.0025% by mass or more and 0.05% by mass or less.   The method for producing an amorphous refractory kneaded product according to any one of claims 1 to 6, wherein the ultrafine powder dispersed in the ultrafine powder dispersion contains ultrafine silica having an average particle size of 10 µm or less.   The refractory construction body which poured and hardened the amorphous refractory kneaded material obtained by the method in any one of Claims 1-7 in a predetermined formwork.