JP2013032247A - Monolithic refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monolithic refractory that is less likely to cause the degradation in toughness in a high-temperature range of, for example, above 1,000°C even when an organic binder is used as a binder.SOLUTION: The monolithic refractory comprises: a refractory powder comprising a coarse particle region where the particle diameter is 1 mm or larger and a fine particle region where the particle diameter is smaller than 1 mm; and the organic binder. A burned olivine is formulated in the fine particle region. The amount of organic binder used is 1 to 20 mass% in outer percentage based on 100 mass% of the refractory powder.

Description

  The present invention relates to an amorphous refractory using an organic binder as a binder.

  Hereinafter, without limitation, the coating material used for forming the tundish coating layer will be described as an example of the amorphous refractory.

  The tundish used in continuous casting of steel has a structure in which a lining refractory is provided inside the iron skin. Furthermore, a coating layer may be formed on the surface of the lining refractory for the purpose of facilitating the processing of the remaining steel and protecting the lining refractory. The coating layer is made of a coating material that is an amorphous refractory.

  As shown in Patent Document 1, the coating material includes a refractory powder composed of a coarse particle region having a particle diameter of 1 mm or more and a fine particle region having a particle diameter of less than 1 mm, and a binder, as in other amorphous refractories. . A magnesia material is generally used for the refractory powder. As binders, inorganic binders such as sodium silicate and organic binders such as phenol resins are known.

JP 2006-7317 A JP 2000-176612 A JP-A-4-130066 Japanese Patent No. 4273099

  When the tundish is used, the coating layer reaches a temperature exceeding 1000 ° C. by receiving heat from the molten steel.

  The inorganic binder is effective for imparting strength in an intermediate temperature range of, for example, 600 ° C. to 1000 ° C., but is a low-melting substance, and therefore becomes a factor that decreases strength and corrosion resistance in a high temperature range exceeding 1000 ° C.

  The organic binder becomes a carbon bond by 1000 ° C. with the dissipation of volatile components contained therein. Since carbon bonds are not easily wetted by slag and are not low melting point substances, they are superior to the effect of imparting strength and corrosion resistance in a high temperature range exceeding 1000 ° C. compared to inorganic binders.

  However, even with carbon bonds, the stability of strength at high temperatures exceeding 1000 ° C. is never satisfactory. Carbon bonds are susceptible to degradation due to oxidation at high temperatures.

  The problem of carbon bond degradation at high temperatures is not limited to coating materials, and generally applies to amorphous refractories using an organic binder as a binder.

  In particular, the carbon bond is likely to be deteriorated in an oxidizing atmosphere, but the carbon bond can be decomposed or dissipated in a high temperature region even in a non-oxidizing atmosphere. Therefore, there has been a demand for an amorphous refractory having excellent strength stability in a high temperature range regardless of whether it is an oxidizing atmosphere or a non-oxidizing atmosphere.

  As a result of the research, the inventors of the present application have improved the stability of strength in the high temperature range by blending the fired olivine into the fine particle region having a particle size of less than 1 mm in the refractory powder even when using the organic binder. I found out. This is presumably because the fired olivine having a particle size of less than 1 mm is easily sintered because the particle size is fine, and the carbon bond is appropriately sintered in a high temperature range where the carbon bond is easily damaged, thereby contributing to the strength.

  Traditionally, olivine is known as a refractory powder in the technical field of refractories. However, there has been no example in which olivine having a particle size of less than 1 mm and previously baked in combination with an organic binder is used. This will be specifically described below.

  Patent Document 2 discloses an example in which olivine is used as an amorphous refractory as a coating material (see Table 1 of Patent Document 2). However, in Patent Document 2, it is not certain whether olivine has been previously baked. Even if this is baked in advance, since olivine is used only in a coarse particle region having a particle diameter of 1 mm or more, olivine is difficult to sinter, and it is difficult to contribute to imparting strength in a high temperature region.

  Patent document 3 is disclosing the example which mix | blended the olivine with a particle size of less than 1 mm with the amorphous refractory used for the casting construction of a molten metal container. However, in patent document 3, it is essential that olivine is unfired. Unfired olivine forms cracks in the structure due to volume expansion during use of the refractory, and is accompanied by the release of crystal water (see Patent Document 3, page 3, upper left column, line 2 to the upper right column, line 5). For this reason, the strength expression of a refractory is rather suppressed. Strength development due to sintering of olivine is exhibited only when olivine is pre-fired.

  Patent Document 4 discloses an example in which a fired olivine having a particle diameter of less than 1 mm is used for an irregular refractory used for spray repair of an electric furnace for steel making (see Tables 2 and 3 of Patent Document 4). However, in patent document 4, all the binders are comprised with the inorganic binder. For this reason, the absolute amount of the inorganic binder used is naturally large, and a large amount of low-melting-point substances derived from the inorganic binder exist at high temperatures. Not.

  An object of the present invention is to provide an amorphous refractory which is less likely to cause a decrease in strength in a high temperature range exceeding 1000 ° C., for example, even though an organic binder is used as the binder.

  According to one aspect of the present invention, it includes a refractory powder composed of a coarse particle region having a particle size of 1 mm or more and a fine particle region having a particle size of less than 1 mm, and an organic binder, and the burned olivine is blended in the fine particle region, and There is provided an amorphous refractory having an organic binder used in an amount of 1% by mass to 20% by mass with respect to the refractory powder.

  In the high temperature range where the carbon bond derived from the organic binder is likely to deteriorate, the fired olivine having a particle size of less than 1 mm is appropriately sintered to increase the strength of the construction body. For this reason, in spite of using an organic binder, it can be made hard to produce the strength fall in a high temperature range.

It is a typical fragmentary sectional view of a tundish.

  Hereinafter, the amorphous refractory according to the embodiment will be specifically described. The amorphous refractory is formed by adding at least an organic binder to a refractory powder.

  The refractory powder consists of a coarse particle region having a particle diameter of 1 mm or more and a fine particle region having a particle diameter of less than 1 mm. The mass ratio between the coarse grain region and the fine grain region is not particularly defined, but will be determined by technical common knowledge of those skilled in the art from the viewpoint of bringing the grain size configuration close to the close-packed structure and obtaining practical corrosion resistance. Typically, 100% by mass of the refractory powder is preferably composed of a coarse particle region: 25 to 65% by mass and a fine particle region: 35 to 75% by mass.

  In the present specification, the particle size of the particle is d or more means that the particle is a particle size remaining on the sieve having an opening d defined in JIS-Z8801, and the particle size of the particle is less than d. Means a particle size passing through the same sieve.

  It is necessary to mix baked olivine in the fine particle region.

  In this specification, calcined olivine means a natural peridotite calcined at 800 ° C. or higher. Peridotite is a complex composed mainly of olivine, and can be accompanied by serpentinized part.

Peridotite is mainly composed of forsterite (2MgO · SiO ₂ ), enstatite (MgO · SiO ₂ ), firelite (2FeO · SiO ₂ ), and cervenine (3MgO · 2SiO ₂ · H ₂ O). Let it be a phase.

Peridotite starts the decomposition reaction shown in the following formulas (1) and (2) from about 800 ° C., for example.
2FeO.SiO ₂ + O ₂ → Fe ₂ O ₃ , Fe ₃ O ₄ + SiO ₂ (1)
3MgO · 2SiO ₂ · 2H ₂ O → Mg ₂ SiO ₄ + SiO ₂ + H ₂ O (2)

  The above equation (2) indicates the release of crystal water. If the release of crystal water occurs during the use of the refractory, the strength development of the refractory is suppressed. On the other hand, calcined olivine obtained by calcining peridotite at 800 ° C. or higher in advance has already released crystal water and is substantially free of crystal water, or at least the content of crystal water from the original peridotite. Less is. For this reason, the intensity | strength fall accompanying discharge | release of crystal water is not caused.

  Table 1 shows a specific example of the chemical composition of the baked olivine. In Table 1, Igloss represents loss on ignition.

As shown in Table 1, most of the fired olivine is MgO. The melting point of MgO is as high as 2850 ° C. However, since the calcination olivine has already finished the decomposition reaction represented by the above formulas (1) and (2) by calcination, the balance contains SiO ₂ and Fe ₂ O ₃ in a free form. As a result, the melting point of the fired olivine is the eutectic point of each component, and is much lower than the melting point of MgO. The melting point of the fired olivine is, for example, 1600 to 1800 ° C.

For the purpose of ensuring the removal of crystal water in the peridotite and the purpose of ensuring the formation of free SiO ₂ and Fe ₂ O ₃ as described above, the firing temperature of the peridotite is preferably 1000 ° C. or higher. 1200 degreeC or more is more preferable.

  The fired olivine blended in the fine particle region is easy to sinter because the particle size is as fine as less than 1 mm. Sintering refers to a phenomenon in which particles are bonded to each other by a solid-phase reaction without a liquid phase at a temperature lower than the melting point. In the case of a fired olivine having a particle size of less than 1 mm, for example, sintering occurs at a temperature of about 1000 to 1200 ° C. or lower, and the sintered state is maintained at least up to the melting point of the fired olivine.

  For this reason, the fired olivine having a particle size of less than 1 mm has an effect of increasing the strength of the construction body by sintering at least in the temperature range of about 1000 to 1200 ° C. to 1600 to 1800 ° C. This temperature range is a temperature range in which the carbon bond derived from the organic binder is likely to deteriorate.

  That is, according to this amorphous refractory, although the organic binder is used, the strength is supplemented by the sintering of the calcined olivine at least in the above temperature range. It can be made difficult to occur.

  Note that inorganic binders such as sodium phosphate and frit have a melting point that is too low and is already in a liquid phase at 1000 ° C., and it is difficult to exert an effect of imparting strength near 1000 ° C. In addition, refractory powders such as magnesia raw material, alumina raw material, and siliceous raw material have a melting point that is too high, and it is difficult to cause sintering at around 1000 ° C. even if blended in the fine particle region. Sintering in the above temperature range where carbon bonds are likely to be deteriorated is a unique effect when fired olivine is used in the fine particle region.

  The lower limit of the ratio of the baked olivine in the fine particle region is not particularly limited. However, in order to increase the certainty of the effect of imparting strength by the above-described fired olivine, it is preferable that 4% by mass or more of the fine particle region is occupied by the fired olivine.

  The upper limit of the ratio of the fired olivine in the fine particle region is not particularly limited, and the entire fine particle region may be composed of the fired olivine, or a refractory powder other than the fired olivine may be included in the fine particle region. However, by suppressing the ratio of the calcined olivine in the fine particle region to 53% by mass or less, oversintering of the calcined olivine can be suppressed, and the heat resistant spalling property can be kept good.

  When including a refractory powder other than calcined olivine in the fine-grained area, the grade of the material is not particularly limited. Calcia raw materials, alumina raw materials such as fused alumina and bauxite, spinel raw materials such as spinel clinker, other oxide raw materials, carbon black raw materials such as carbon black, silicon carbide raw materials, silicon nitride raw materials, other non One or more selected from oxide raw materials and used refractory wastes mainly composed of at least one of them can be used.

  When a refractory powder other than calcined olivine is included in the fine particle region, the remainder other than calcined olivine is preferably composed of a raw material having a melting point higher than that of calcined olivine. Thereby, the oversintering of the matrix part which consists of a fine-grain area can be suppressed, and the heat resistant spalling property can be improved. Conventional refractory powder, at least each of the raw materials exemplified above, has a higher melting point than calcined olivine. Among them, the magnesia raw material not only has a high melting point, but also contains MgO as the main component, similar to calcined olivine, so it contributes to improving the integrity and continuity of the structure of the matrix part composed of fine-grained areas and improving strength and corrosion resistance. To do.

  The raw material which comprises a coarse grain area | region is not specifically limited, For example, each raw material illustrated above can be used similarly to the case of a fine grain area | region.

However, it is preferable to mix baked olivine also in the coarse grain region. Thereby, the corrosion resistance is improved. This is because the fired olivine increases the viscosity of the slag by elution of the SiO ₂ component, forms a viscous protective film on the surface of the refractory, and has the effect of preventing the penetration of the slag. In addition, since fired olivine is blended in the fine-grained area, by combining fired olivine in the coarse-grained area, the integrity or continuity of the structure of the coarse-grained area and the fine-grained area is increased, and the strength and corrosion resistance are improved. Contribute to.

  In order to enhance the certainty of such an effect, it is preferable that 35% by mass or more of the coarse grain region is composed of baked olivine. The coarse grain region is coarse with a particle size of 1 mm or more and is hard to sinter compared to the fine grain region. Therefore, even if a large amount of fired olivine is used in the coarse grain region, the problem of oversintering does not occur.

  The coarse particle region preferably contains particles having a particle size of 3 mm or more. Even if cracks occur in the refractory, propagation of the particles can be prevented. Although the maximum particle size of the coarse grain region is not particularly limited, for example, 10 mm or less is preferable, and 8 mm or less is more preferable.

  The amount of the organic binder used is required to be 1% by mass or more and 20% by mass or less based on 100% by mass of the refractory powder. This is because if it is less than 1% by mass, the minimum strength as a construction body cannot be secured. Moreover, it is because volume stability will deteriorate and a crack will be produced when it exceeds 20 mass%. In addition, the ratio of the organic binder to 100% by mass of the refractory powder is preferably 2% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 6% by mass or less.

  As the organic binder, a substance that forms a carbon bond with heat, for example, one or more selected from resins, saccharides, pitch, tar, and other bitumen can be used. Examples of the resin include phenol resin, furan resin, epoxy resin, melamine resin, and terpene resin. A curing agent such as hexamethylenetetramine may be used in combination with the resin. In this case, the curing agent is also included in the concept of the organic binder. Examples of the saccharide include monosaccharides such as glucose, fructose, galactose, and mannose, and disaccharides such as sucrose, maltose, lactose, cellobiose, and trehalose. Pitch and tar may be either petroleum-based or coal-based. A solvent containing, for example, a polyhydric alcohol may be used together with the resin and pitch, and in this case, the solvent is also included in the concept of the organic binder. When pitch and resin are used in combination, a solvent compatible with both is preferable.

  An inorganic binder may be used in combination with the organic binder. As the inorganic binder, for example, one or more selected from silicate, phosphate, boric acid, borate, borax, frit, and cement can be used. Examples of the silicate include sodium silicate, potassium silicate, and calcium silicate. Examples of the phosphate include sodium hexametaphosphate, sodium pyrophosphate, sodium tetrapolyphosphate, sodium tripolyphosphate, sodium ultraphosphate, potassium phosphate, lithium phosphate, calcium phosphate, magnesium phosphate, and aluminum phosphate. Examples of the cement include alumina cement, magnesia cement, and Portland cement. A frit is a glass powder obtained by melting, quenching and pulverizing a starting material containing at least one selected from silicates, phosphates, lithium carbonate, sodium fluoride, and borates. And borosilicate glass and zircon glass.

  The melting point of the inorganic binder is less than 1000 ° C., typically 300 to 900 ° C., and by itself, the bond form cannot be maintained in a high temperature range exceeding 1000 ° C., so that there is almost no effect of imparting strength.

  However, in this embodiment, the inorganic binder is used not for the purpose of forming a bond but for the purpose of promoting the sintering of the fired olivine. That is, by using the inorganic binder, sintering is started from a low temperature, specifically, for example, about 700 to 800 ° C. due to a decrease in the interfacial energy of the baked olivine particles in the fine particle region. For this reason, the temperature range where intensity | strength is provided by the baking olivine of a fine particle area expands. For example, even when the deterioration of the carbon bond can start from 1000 ° C. or lower, such as when the present refractory is used in an oxidizing atmosphere, a decrease in strength can be suppressed.

  When the inorganic binder is used for the purpose of accelerating the sintering of the fired olivine, the amount used is 50% by mass or less in the proportion of the binder. With this addition amount, the decrease in corrosion resistance accompanying the generation of the low melting point substance can be ignored.

  The amorphous refractory may be composed only of the refractory powder and the binder, but may further include other additives.

  Examples of the other additive include one or more selected from organic fibers, metal fibers, metal powders, viscosity modifiers, and dispersants. Examples of the organic fiber include vinylon fiber, polyethylene fiber, polypropylene fiber, and pulp fiber, which have an effect of improving workability, heat insulation, and stress relaxation between heat. Examples of the metal fiber include stainless steel fiber, Fe fiber, Cu fiber, Al fiber, and Ni fiber. Examples of the metal powder include Fe powder, Cu powder, Al powder, metal Si powder, and Fe—Si alloy powder. Viscosity modifiers include kerosene, heavy oil, creosote oil, anthracene oil and other coal or petroleum-based oils, vegetable oils, animal oils, ethers, lactams such as caprolactam, acetanilides such as acetanilide and acetoacetanilide, and butylphenol. Examples include alkylphenols. The viscosity modifier has the effect of preventing dust generation and promoting flow. From the concept of viscosity modifier, the solvent used in the binder described above is excluded. Examples of the dispersant include an anionic modified lignin lignin sulfonate and β-naphthalene sulfonate.

  Hereinafter, a tundish dry coating method using the above-described amorphous refractory as a coating material will be described.

  1A to 1D are schematic partial cross-sectional views of a tundish. The tundish has a structure in which a lining refractory 2 is provided inside the iron skin 1.

  As shown in FIG. 1 (a), first, an indeterminate refractory 4 is spread on the bottom of the tundish in powder form without adding water, and after leveling, the core is placed in the tundish. 3 is inserted. The core 3 has a hollow container shape having an outer surface shape corresponding to the inner surface shape of the tundish, and is made of a metal plate such as an iron plate, for example.

  Next, as shown in FIG.1 (b), the amorphous refractory 4 is filled into the clearance gap between the side surface of a tundish, and the core 3 with the powder form, without adding water to this. When filling the irregular refractory 4, it is preferable to apply vibration to the irregular refractory 4 in order to reduce the gap and densely fill.

  This completes the preparation of the state in which the amorphous refractory is filled in powder form without adding water between the core 3 inserted into the tundish and the lining refractory 2 of the tundish.

  In the case where the coating layer is formed only on the side surface of the tundish, it is not necessary to spread the amorphous refractory on the bottom surface of the tundish as shown in FIG.

  Next, as shown in FIG. 1C, the amorphous refractory 4 is heated to 100 to 400 ° C. from the inside of the core 3 through the core 3. For the heating, for example, a burner or a warm air machine is used. The heating time is, for example, 2 to 20 minutes. By this heating, the organic binder in the amorphous refractory 4 is softened and expresses shape retention.

  Next, as shown in FIG. 1 (d), the core 3 is removed from the tundish. Thereby, the coating layer 5 is obtained.

  Next, the tundish is put into use. When the tundish is used, the temperature of the coating layer 5 reaches a temperature exceeding 1000 ° C. by receiving heat from the molten steel. Thereby, the organic binder in the coating layer 5 is carbon-bonded, and strength is imparted to the coating layer 5.

  However, carbon bonds are liable to be deteriorated by oxidation in a high temperature range exceeding 1000 ° C. Since the thickness of the coating layer 5 is as thin as about 5 to 100 mm, it is particularly important to stabilize the strength of the coating layer 5. In this respect, the sintered olivine having a particle diameter of less than 1 mm in the coating layer 5 is sintered in a temperature range where the carbon bond is likely to be oxidized, and the coating layer 5 is given strength, thereby stabilizing the strength of the coating layer 5. Can be achieved.

  Next, when the coating layer 5 is worn out by continuing use of the tundish, the coating layer is formed again. For that purpose, first, after the use of the tundish is stopped, the remaining steel and the residue of the coating layer 5 formed previously are removed from the surface of the lining refractory 2, and the above-described procedure is repeated again.

  Note that the method of applying the amorphous refractory to the tundish lining refractory is not particularly limited to the dry coating method described above. It is also possible to add water to the amorphous refractory and spray or trowel on the lining refractory.

  However, when water is used for construction in the coating layer application, the amorphous refractory and the lining refractory are in close contact with each other during construction, resulting in excessive seizure of the amorphous refractory on the lining refractory. Cheap. Since the present irregular refractory contains a fired olivine having a particle size of less than 1 mm which is easy to sinter, the seizure tends to be excessive.

  The coating layer is desired to have a small amount of seizure to the base, that is, the lining refractory, unlike an ordinary refractory for repair, such as a baked repair material, from the viewpoint of easy removal. When this amorphous refractory is used to form a coating layer, the dry coating method can be used to prevent the adhesion between the amorphous refractory and the lining refractory from becoming too high during construction. In spite of containing a fired olivine having a particle size of less than 1 mm, which is easy to cause, excessive seizure to the lining refractory 2 can be made difficult to occur.

  In Tables 2-4, the structure and evaluation result of an amorphous refractory by an Example and a comparative example are shown. In Tables 2 to 4, those shown in Table 1 were used as the baked olivines in the fine grain region and the coarse grain region.

  Hereinafter, the evaluation items in Tables 2 to 4 will be described.

  Hot strength: A frame having an internal size of 30 × 30 × 120 mm was filled with an amorphous refractory and dried at 200 ° C. Then, the amorphous refractory obtained by removing the frame was evaluated. Specifically, the bending strength at a span of 100 mm was measured in a hot state at 1200 ° C., and relative evaluation was performed in four stages of ◎, ◯, Δ, and × based on the hot bending strength. In the four-stage relative evaluation, the evaluation results are excellent in the order of ◎, ○, Δ, and ×.

  Heat resistant spalling property: A sample filled with an irregular refractory, heated at 1000 ° C for 10 minutes and solidified is repeatedly immersed in molten steel at 1500 ° C and left at room temperature, causing the sample to collapse. The number of repetitions was measured. Depending on the number of repetitions, relative evaluation was performed in four stages of ◎, ○, Δ, and ×. In the four-stage relative evaluation, the evaluation results are excellent in the order of ◎, ○, Δ, and ×.

  Corrosion resistance: An erosion test using a high-frequency induction furnace was performed on a sample which was filled with an irregular refractory and heated at 1000 ° C. for 10 minutes to solidify. As the erodant, a combination of converter slag and steel slabs at a mass ratio of 1: 1 was used, and after erosion at 1500 ° C. for 3 hours, the average erosion dimension was measured. Relative evaluation was made in four stages of ◎, ○, Δ, and × depending on the average erosion dimension. In the four-stage relative evaluation, the evaluation results are excellent in the order of ◎, ○, Δ, and ×.

  Table 2 shows the results of various changes in the proportion of the burned olivine in the fine particle region.

  Example 1 is a comparative example in which no calcined olivine is blended in the fine particle region. As shown in Example 2, even when the ratio of the calcined olivine in the fine particle region is as small as 4% by mass, the effect of improving the hot strength at 1200 ° C. is seen as compared with Example 1. As shown in Examples 3 to 6, when the ratio of the baked olivine in the fine particle region is 18% by mass or more, the effect of improving the hot strength at 1200 ° C. becomes remarkable.

Moreover, when the ratio of the baked olivine in the fine particle region was 18% by mass or more, the corrosion resistance was improved as compared with the cases where the ratio of the burned olivine in the fine particle region was 0% by mass and 4% by mass. This is thought to be due to the fact that the burned olivine increased the viscosity of the erodant by elution of SiO ₂ and formed a thick protective film on the surface of the refractory, thereby preventing the penetration of the erodant. .

  However, as shown in Example 6, when the ratio of the baked olivine in the fine particle region exceeds 53% by mass, the heat resistant spalling property is lowered. This is thought to be because the sintering by the fired olivine in the fine particle region became excessive. Considering the above results comprehensively, it is preferable that the ratio of the burned olivine in the fine particle region is 4 mass% or more and 53 mass% or less.

  Table 3 shows the results of various changes in the amounts of organic and inorganic binders used in the binder, based on Example 3 in Table 2.

  As shown in Example 7, when the organic binder is less than 1% by mass with respect to 100% by mass of the refractory powder, the amount of carbon bond formed is too small and the hot strength at 1200 ° C. is reduced. At the same time, heat-resistant spalling properties and corrosion resistance decreased.

  Further, in Example 7, since all of the binder was an inorganic binder, no effect of improving the hot strength at 1200 ° C. was observed even though the fine particle region contained baked olivine. This is because the relative amount of the inorganic binder used is too large, and a large amount of liquid phase derived from the low-melting-point material is generated hot, so that the fired olivine exhibits the effect of strength development by sintering. It is thought that it was not possible.

  Example 19 is an amorphous refractory containing an organic binder of 25% by mass on the basis of 100% by mass of the refractory powder. In this case, since the amount of the organic binder is relatively larger than the case of containing an organic binder of 20% by mass or less on the basis of 100% by mass of the refractory powder, shrinkage or expansion during carbonization or decomposition is caused. As a result, the volume stability deteriorates and cracks occur.

  As described above, according to the results shown in Table 3, the organic binder needs to be 1% by mass or more and 20% by mass or less based on 100% by mass of the refractory powder. This is because if it is less than 1% by mass, the minimum strength as a construction body cannot be secured. Moreover, it is because volume stability will deteriorate and a crack will be produced when it exceeds 20 mass%. In addition, the ratio of the organic binder to 100% by mass of the refractory powder is preferably 2% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 6% by mass or less.

  Table 4 shows the result of variously changing the ratio of the baked olivine in the coarse grain region based on Example 11 in Table 3.

When 35% by mass or more of the coarse grain region is composed of calcined olivine, a further improvement effect of corrosion resistance is observed. This is presumably because the baked olivine in the coarse-grained area formed a highly viscous silicate film by elution of SiO ₂ , which showed the effect of suppressing the penetration of the erodant into the matrix part.

  As mentioned above, although the specific example of this invention was demonstrated, this invention is not limited to this. For example, it will be apparent to those skilled in the art that various combinations and improvements are possible.

  The amorphous refractory of the present invention is not limited to a tundish, for example, a converter, an AOD furnace, a VOD furnace, an RH-type or DH-type vacuum degassing furnace, other refining furnaces, an electric furnace, a ladle, a cocoon, etc. It can be widely used for forming or repairing the lining of pots, brewers and other molten metal containers.

  The use environment after the construction of the amorphous refractory according to the present invention may be an oxidizing atmosphere or a non-oxidizing atmosphere. In particular, since the carbon bond is likely to be deteriorated in an oxidizing atmosphere, the present invention is particularly significant for use in an oxidizing atmosphere.

  The amorphous refractory of the present invention can be used for both warm construction and hot construction. In this specification, the hot construction means a case where the temperature of the construction target surface is 600 ° C. or higher, and the warm construction means a case where the temperature of the construction target surface is normal temperature to less than 600 ° C.

  As an example specific to the warm construction method, an amorphous refractory was filled in powder form without adding water between the core inserted into the molten metal container and the lining refractory of the molten metal container. There is a dry coating method having a step of preparing a state and a step of removing the core from the molten metal container after heating the amorphous refractory through the core. In addition, examples of methods specific to the warm construction method include troweling, stamping, and ramming.

  As an example peculiar to the hot construction method, there is a method in which the amorphous refractory is packed in a combustible bag such as a flexible bag or a vinyl bag and thrown into a construction target site.

  As an example that can be applied to both hot construction and warm construction, there is a spray construction method in which the amorphous refractory is fed into a hollow tube, air-flowed, and sprayed onto a construction target surface. In the spray construction method, water may be added to the amorphous refractory in the hollow tube and / or in the nozzle connected to the tip of the hollow tube. Even when water is used for the construction, the water shall be excluded from the constituent requirements of the amorphous refractory. Moreover, you may add the inorganic binder as a structural requirement of this amorphous refractory within the hollow tube and / or the nozzle connected to the front-end | tip of the hollow tube.

  The properties of the amorphous refractory are not particularly limited. By using a powdery binder, for example, a powdered phenol resin, the amorphous refractory can be powdered. In addition, for example, by using a liquid as a part of the binder or using a small amount of a viscosity modifier, the amorphous refractory can be made wet enough to carry air current. . In addition, the amorphous refractory can be made into a slurry or kneaded clay by using a liquid binder, or using a viscosity modifier in combination even if the binder is powdery. . It will be apparent to those skilled in the art that the properties of the irregular refractory can be adjusted according to the construction method.

  DESCRIPTION OF SYMBOLS 1 ... Iron skin, 2 ... Lined refractory material, 3 ... Core, 4 ... Amorphous refractory material, 5 ... Coating layer.

Claims (3)

  A refractory powder composed of a coarse particle region having a particle diameter of 1 mm or more and a fine particle region having a particle diameter of less than 1 mm, and an organic binder, and calcined olivine is blended in the fine particle region, and the amount of the organic binder used is An amorphous refractory that is 1% by mass to 20% by mass with respect to 100% by mass of the refractory powder.   The amorphous refractory according to claim 1, wherein the coarse grain region is also mixed with fired olivine, and 35 mass% or more of the coarse grain region is composed of the fired olivine.   A tundish obtained by forming the amorphous refractory according to claim 1 or 2 on a coating layer by a dry coating method.

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