JP4744066B2 - Indefinite refractory - Google Patents

Description

【００６３】
【表２】

【００６４】
【発明の効果】
以上の説明のように、本発明により高耐食性で高強度の不定形耐火物を得ることができる。これにより各種窯炉の耐火物ライニングの寿命を延長し、耐火物コストと鉄鋼などの製造コストを引き下げることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an irregular refractory for casting construction or the like.
[0002]
[Prior art]
A refractory for casting construction (hereinafter referred to as “a casting material”) used as a refractory for a molten steel container such as a ladle, a tundish, a vacuum degassing furnace, or a molten steel processing apparatus is widely used.
However, the use conditions of molten steel containers and molten steel processing equipment in recent years have continued to become severe due to rising molten steel temperature, extension of molten metal time, gas blowing stirring, etc., for example, high durability such as alumina-magnesia However, the service life is never sufficient, and there is a strong demand for a casting material with excellent durability.
[0003]
As an improvement measure, Patent Document 1 proposes an alumina-magnesia casting material in which aluminum lactate is added to a binder. Here, aluminum lactate is used as the binder, and the alumina cement and SiO that are CaO sources.₂ By removing the source silica, the effect of improving the resistance to melting loss and improving the heat spalling resistance by suppressing the sintering is obtained.
Patent Document 2 also proposes an alumina-magnesia casting material obtained by adding aluminum lactate to a binder as a material for wet spraying construction and excluding alumina cement as a CaO source.
[0004]
Further, Patent Document 3 describes one in which sodium silicate, sodium borosilicate, or potassium silicate is added as a measure for suppressing the strength reduction of the amorphous refractory containing no alumina cement.
Furthermore, Patent Document 4 describes an amorphous refractory material mainly composed of a zircon-containing magnesia aggregate and exhibiting strength in a medium to low temperature range by adding phosphate glass and borosilicate glass.
[0005]
[Patent Document 1]
JP-A-11-130550
[Patent Document 2]
Japanese Patent Laid-Open No. 10-194853
[Patent Document 3]
JP-A-5-213675
[Patent Document 4]
JP-A-6-144939
[0006]
[Problems to be solved by the invention]
Alumina cement is one of the typical binders for imparting strength to the casting material. However, CaO contained therein is a cause of impairing the corrosion resistance of the casting material. Therefore, casting materials which do not contain aluminum cement as described in Patent Document 1 and Patent Document 2 have been proposed. However, a common problem with casting materials that do not contain alumina cement is that the strength after firing at a medium to low temperature around 1000 ° C. (referred to as the strength in the medium to low temperature range) is low. Patent Document 3 describes the addition of sodium silicate, sodium borosilicate, and potassium silicate as means for solving this problem. However, sufficient effects cannot be obtained even with these means.
[0007]
On the other hand, as for the basic casting material, an amorphous refractory material that exhibits strength in a medium to low temperature range by adding phosphate glass and borosilicate glass as proposed in Patent Document 4 has been proposed. The added glass liquefies around 1000 ° C. and bonds magnesia to develop strength, but has a serious problem that the hot strength at 1400 ° C. or higher is remarkably lowered.
[0008]
An object of the present invention is to provide a highly durable amorphous refractory having an enhanced strength in the medium and low temperature range without impairing the hot strength of the highly corrosion-resistant cast material containing no alumina cement.
[0009]
[Means for Solving the Problems]
  Various inventions were accumulated to achieve the above-mentioned object, and the present invention was obtained. That is, P₂O₅0.1-3 mass%, CaO 0.5 mass% or less, SiO₂0.05 to 5% by mass, the total amount of lactic acid and glycolic acid is 0.005 to 1% by mass, and the balance is Al.₂O₃Amorphous refractory of alumina-magnesia, alumina-spinel, or alumina-magnesia-spinel composed of MgO and other inevitable components,By not blending alumina cement, the CaO is 0.5 mass% or less,
and,P₂O₅Ingredient is P₂O₅It is supplied by adding the contained powder.₂O₅The contained powder further contains Na₂O component, B₂O₃Contains either or both of the ingredients, P₂O₅As content in the contained powder, P₂O₅10 to 70% by mass, Na₂10-30% by mass of O, B₂O₃5-60 mass%, P₂O₅And Na₂O and B₂O₃Is 50% by mass or more,
  And, in a proportion of 100% by mass of the refractory aggregate composition, 3 to 15% by mass of alumina ultrafine powder having an average particle size of 1.5 μm or less, an iodine absorption of 20 iodine mg / g or more and an average particle size of 1 μm or less It is an amorphous refractory characterized by containing 0.01 to 3 mass% of light-burned magnesia fine powder.
  Furthermore, a peptizer, refractory coarse particles, a curing modifier, short metal fibers, organic fibers, ceramic fibers, carbon fibers, chromium ore, and a foaming agent may be added as a casting material.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention uses P as a casting material containing no alumina cement.₂ O_Five Mixing fine powder or particles (collectively referred to as “powder”) containing, the strength in the mid-low temperature range is expressed. This method does not decrease the hot strength of the casting material, but rather increases the corrosion resistance.
[0011]
In this specification, Al₂ O_Three , MgO and the like represented by chemical formulas represent chemical components and can be quantified by chemical analysis. On the other hand, what is written in katakana such as alumina and magnesia represents a substance that becomes a refractory raw material such as a mineral, that is, exists as one phase. In other words, the substance is in a state that becomes an actual refractory raw material that may contain inevitable impurities that can be taken out without chemical manipulation. For example, alumina has the mineral name Corundum, and magnesia has the mineral name Pericles. Those represented by chemical formulas can be identified and quantified by chemical analysis, and those represented by katakana can be identified and quantified by a method such as X-ray diffraction.
[0012]
Substances which are the main components of the refractory of the present invention are alumina (corundum), spinel, and magnesia (pericles). That is, the main chemical component is Al₂ O_Three Or / and MgO. Since the refractory composed of these main components has a high melting point and high corrosion resistance against slag and molten iron, alumina cement containing a CaO component that impairs these properties is not blended. In addition, even if it does not mix | blend a CaO component as an alumina cement, 0.5 mass% or less is contained as an impurity in a main component substance. However, this CaO component does not cause harm because it is compounded or dissolved in the main component material and is firmly taken in. For this reason, CaO contained by 0.5 mass% or less in the whole refractory is allowed.
[0013]
P₂ O_Five Components are added in a total amount of 0.1 to 3% by mass. This component promotes the sintering of main component materials such as alumina, spinel, and magnesia, and functions to develop strength in the mid-low temperature range. If it is less than 0.1% by mass, the intended strength is not exhibited, and if it is added in excess of 3% by mass, the corrosion resistance is reduced. The lower limit is preferably 0.3, and more preferably 0.5% by mass. By the way, peptizers are usually used for amorphous refractories.₂ O_Five In many cases, the component is contained in an amount of about 0.05% by mass, but this does not contribute to the strength development in the medium to low temperature range intended in the present invention.
[0014]
P₂ O_Five The component is added as a powder containing this component. The powder contains Na₂ O and / or B₂ O_Three Ingredients may be contained. The total content of these three components is desirably 50% by mass or more. Below this, strength is difficult to develop due to dilution effect by other components. P₂ O_Five Content 10-70 mass%, Na₂ O content 10-30% by mass, B₂ O_Three A material having a content of about 5 to 60% by mass is easy to use. It may be vitrified instead of crystalline.
[0015]
The refractory of the present invention is P₂ O_Five Despite containing ingredients, hot strength is high. This is clear when the present invention example D01 and the comparative example D13 in the examples described later are compared, and the difference from the prior art (for example, the invention described in Patent Document 4) is conspicuous. The cause is presumed as follows. That is, P₂ O_Five Coexists with CaO, the melting point tends to decrease.₂ O_Three Since such a tendency is weak, the refractory of the present invention containing almost no CaO does not decrease the hot strength, but rather P₂ O_Five The hot strength increases due to the sintering-promoting effect of the components.
[0016]
SiO₂ Is derived from silica-based raw materials such as volatile silica and meteorite. In particular, volatile silica is added for the purpose of suppressing magnesia hydration during curing and drying of the amorphous refractory construction body, imparting appropriate creep properties at high temperatures, and improving corrosion resistance if appropriate. SiO in refractories₂ If the amount of the component is less than 0.05% by mass, magnesia hydrates, and problems such as destruction of the refractory due to insufficient creep properties occur, and if it exceeds 5% by mass, corrosion resistance deteriorates. It limits to the range of 0.05-5 mass%.
[0017]
When both alumina and magnesia are contained, they react with each other during heat reception during use to produce spinel, and the refractory expands at that time, which may destroy the irregular refractory construction body. To prevent this, SiO₂ Is required to be 0.5 mass% or more. The upper limit may be 5% by mass in the same manner due to the decrease in corrosion resistance.
[0018]
The total amount of lactic acid and glycolic acid is 0.005 to 1% by mass. This is an amount corresponding to the added amount of 0.01 to 2% by mass of aluminum lactate, aluminum glycolate, aluminum glycolate and the like described later. Aluminum lactate, aluminum glycolate, and aluminum glycolate act as binders (binders) of the main component, give alumina refractory construction body a strength after curing and drying instead of alumina cement, and curing drying Occasionally, microcracks are generated to provide air permeability and absorb the thermal expansion of the refractory itself, thereby improving the spall resistance and providing an appropriate creep property.
[0019]
Aluminum lactate, aluminum glycolate, and aluminum glycolate are composed of lactic acid, glycolic acid, and aluminum ions (or aluminum oxide in terms of oxides), so the amount of lactic acid or glycolic acid is aluminum lactate, aluminum glycolate, glycol glycol Less than the amount of aluminum oxide added. If the total amount of lactic acid and glycolic acid is less than 0.005% by mass (that is, the total amount of aluminum lactate, aluminum glycolate and aluminum lactate is less than 0.01% by mass), the strength after curing is insufficient. At the same time, there is no effect of generating microcracks, and the accompanying effect is not obtained. Moreover, when it exceeds 1 mass% (that is, when the total amount of aluminum lactate, aluminum glycol glycolate, and aluminum glycolate exceeds 2 mass%), cracks due to curing shrinkage occur, and the corrosion resistance of the refractory decreases.
[0020]
If the amount of lactic acid and glycolic acid in the refractory is managed, the performance of the refractory can be managed and grasped more accurately than the addition ratio of aluminum lactate, aluminum glycolate, aluminum glycolate and the like to be described later. This is because commercially available aluminum lactate, aluminum lactate glycolate, and aluminum glycolate contain diluents and extenders, and the amount of components such as aluminum lactate is not constant.
[0021]
In the present invention, the following method was used as a method for measuring the amounts of lactic acid and glycolic acid in the refractory. That is, in accordance with the dissolution test method for soil etc. of Environment Agency Notification No. 46, a sample of 2 mm or less and a pure water adjusted to pH 5.8 to 6.3 is 10% by mass / volume ratio (50 g of sample and 500 ml of pure water). Mix at a ratio and shake continuously for 6 hours at room temperature and normal pressure using a shaker (shaking width 4-5 cm, 200 times per minute). This solution was allowed to stand for 30 minutes, and then the supernatant obtained by centrifuging at about 3000 revolutions per minute was filtered through a membrane filter having a pore size of 0.45 μm to obtain a measurement solution. This was measured by capillary zone electrophoresis or high performance liquid chromatography. In capillary zone electrophoresis, fused silica capillaries were used, and sample injection was performed by the drop method. Detection was based on ultraviolet absorption by the on-column method. In the high performance liquid chromatograph method, a normal column having an inner diameter of 3 to 4 mm was used, and the ultraviolet absorbance was measured at a flow rate of about 0.5 to 2 ml / min. The detection sensitivity is superior to capillary electrophoresis. The difference between the two results was within 20%.
[0022]
  Inevitable ingredients are iron oxide, MnO, TiO₂, Na₂ O, V ₂O₅, C and other elements having stable nuclides, or compounds such as oxides, both of which adversely affect the corrosion resistance and the like, and are desirably 5% by mass or less.
[0023]
In the refractory of the present invention, particularly excellent characteristics can be obtained by appropriately blending alumina, spinel, magnesia, and silica, which are main component substances, and further blending in consideration of the following points. That is, 3 to 15% by mass of alumina ultrafine powder having an average particle size of 1.5 μm or less, and 0.01 to 2 mass in total of one or more of aluminum lactate, aluminum glycolate, and aluminum glycolate. %, And a light-burned magnesia fine powder having an iodine adsorption amount of 20 iodine mg / g or more and an average particle diameter of 1 μm or less is contained in an amount of 0.01 to 3 mass%. The intention is that the strength after curing is ensured by ultrafine alumina powder, aluminum lactate, aluminum glycolate, and aluminum glycolate, and cracking during curing is suppressed by lightly burned magnesia fine powder.
[0024]
The alumina ultrafine powder imparts strength to the construction body due to its cohesive force. In addition, since the structure is densified, corrosion resistance and slag infiltration resistance are improved. The average particle size of 1.5 μm or less is to increase the filling property of the matrix part of the construction body structure, thereby eliminating the extra space between the particles, and the aluminum lactate, aluminum glycolate, and aluminum glycolate described later. It is for making the effect of this invention which prevents the shrinkage crack accompanying gelling more reliable.
[0025]
  The amount of the ultrafine alumina powder is 3 to 15% by mass with respect to 100% by mass of the refractory aggregate composition, and the average particle size is 1.5 μm or less. If the proportion of the ultrafine alumina powder is less than 3% by mass, the effect of preventing the shrinkage crack of the construction body is inferior.To doOr spalling resistance decreases.
[0026]
The use of calcined alumina is preferable because the ultrafine alumina powder is easily available from commercial products. The calcined alumina is known in various particle sizes. In the present invention, as long as 3 to 15% by mass of alumina ultrafine powder having an average particle diameter of 1.5 μm or less is used, alumina ultrafine powder having other particle diameters may be combined. Moreover, you may combine multiple alumina ultrafine powder from which a particle size differs in the range of an average particle size of 1.5 micrometers or less.
[0027]
Aluminum lactate, aluminum glycolate, and aluminum glycolate function as a binder that hardens the cast material during curing by gelation by reaction with construction water, and the structure of the construction body is expanded and contracted by the gelation. To form fine cracks. As described above, the microcracks remain in the structure when the construction body is dried and heated, and thus effectively work to impart air permeability, absorb expansion, and reduce thermal stress.
[0028]
Aluminum lactate, aluminum glycolate, or aluminum glycolate may be added as a powder and kneaded with other raw materials, or may be added after previously defrosting with water.
Aluminum lactate includes, for example, aluminum lactate in a narrow sense, and includes basic aluminum lactate, aluminum citrate lactate, and the like as described in JP-A-9-194264, for example. For example, basic aluminum lactate is produced by reacting water-soluble aluminum with carbonate or carbonate and lactic acid. Al for aluminum lactate₂ O_Three / Lactic acid having a molar ratio of 0.3 to 2 is preferable, but is not limited thereto.
[0029]
Aluminum glycolate is included in a broad sense of aluminum lactate. For example, it can be obtained by making glycolic acid, which is an organic acid, into an aluminum lactate salt and drying it. Al₂ O_Three Although / (lactic acid + glycolic acid) is preferably 0.3 to 2 in terms of molar ratio, it is not limited thereto.
[0030]
Aluminum glycolate is Al₂ O_Three / Glycolic acid preferably has a molar ratio of 0.3 to 2, but is not limited thereto.
Furthermore, by adding light-burned magnesia, the intended effects of volume stability and corrosion resistance can be obtained. The reason is considered as follows. Although the fine crack by the gelatinization reaction of aluminum lactate, aluminum glycolate, or aluminum glycolate exhibits various effects as described above, cracks due to curing shrinkage occur at the same time. This crack due to curing shrinkage has a much larger crack width than the fine crack caused by the gelation reaction, and causes a decrease in corrosion resistance. On the other hand, by combining light-burned magnesia, gelled aluminum lactate, glycolate aluminum lactate, and aluminum glycolate are adsorbed to Mg eluted from the light burnt magnesia during kneading, and aluminum lactate, aluminum glycolate, lactate, glycolic acid By suppressing the rapid gelation reaction observed when aluminum is used alone, shrinkage cracks during curing are prevented.
[0031]
Moreover, it is in the curing form in which magnesia and alumina are already bonded at the time of curing by reaction of light-burned magnesia with aluminum lactate, aluminum glycolate, and aluminum glycolate, and these are spineled at a relatively low temperature range. The spinel produced here has a very fine particle size. This contributes greatly to the improvement of corrosion resistance and volume stability in combination with the prevention of shrinkage cracks during curing.
[0032]
These effects according to the present invention are such that, among light-burned magnesia, the iodine adsorption amount is 20 iodine mg / g or more, more preferably 30 to 200 iodine mg / g, and the average particle size is 1 μm or less, more preferably 0.5 μm or less. It is more effectively demonstrated by using light-burned magnesia fine powder. If the lightly adsorbed magnesia fine powder has an iodine adsorption amount of less than 20 iodomg / g, the reaction with aluminum lactate, aluminum glycolate, or aluminum glycolate is inferior, or there is no effect in preventing shrinkage cracks during curing. Further, if the iodine adsorption amount of the light-burned magnesia fine powder exceeds 200 iodine mg / g, the hydration reaction tends to occur and the digestion resistance of the refractory structure tends to be lowered, which is not preferable. If the average particle size exceeds 1 μm, even if the iodine adsorption amount is 20 iodomg / g or more, the reaction with aluminum lactate, glycolic acid aluminum lactate, or aluminum glycolate is slow, or the effect of preventing shrinkage cracking during curing There is no. Even if either the iodine adsorption amount or the average particle diameter is out of this range, the effect aimed by the present invention cannot be obtained.
[0033]
The measurement of the iodine adsorption amount here can be performed according to JIS-K6338 which is a method for measuring the surface properties of magnesia fine powder. The average particle size can be measured by a laser diffraction method. Moreover, the particle size measurement of the alumina ultrafine powder mentioned later can also be measured by the laser diffraction method.
[0034]
If the amount of lightly burned magnesia fine powder is less than 0.01% by mass in the proportion of 100% by mass of the refractory aggregate composition, there is no effect of preventing curing shrinkage. If it exceeds 3% by mass, the cast material becomes difficult to knead due to a high fiscal year, and it is difficult to obtain a dense construction body due to a decrease in fluidity during construction.
[0035]
The light-burned magnesia fine powder is obtained by baking magnesium hydroxide at a relatively low temperature range, and the amount of iodine adsorption varies depending on operations such as particle size adjustment and baking temperature in the production process. Various qualities are commercially available in terms of iodine adsorption amount and particle size, and the light-burned magnesia fine powder used in the present invention can also be obtained from this commercially available product. In addition, if the light-adsorbed magnesia fine powder with the iodine adsorption amount and particle size limited in the present invention is used in an amount within the range limited in the present invention, the light-adsorbed magnesia fine powder with other iodine adsorption amount and particle size is used in combination. May be.
[0036]
The raw material used for the refractory of the present invention will be described below.
The alumina raw material is a refractory raw material having both corrosion resistance and volume stability. It does not matter whether it is an electromelted product or a sintered product. For use in the fine powder portion, calcined alumina that is easily available as fine powder may be used. Al₂ O_Three The purity is preferably 95% by mass or more.
[0037]
As the spinel raw material, electrofused or sintered spinel, spinel-type iron ore can be used. Al₂ O_Three Impurities other than MgO are preferably less than 80% by mass. Those outside the stoichiometric composition can also be used.
[0038]
The magnesia raw material may be either a sintered product or an electromelted product. The MgO purity is 90% by mass or more, more preferably 95% by mass.
[0039]
A part or all of the magnesia raw material used in the present invention may be magnesium carbonate having a chemical analysis value of MgO content of 35% by mass or more. As the magnesium carbonate, natural magnesite, synthetic magnesium carbonate, magnesium carbonate hydroxide (basic magnesium carbonate) or the like can be used, and the MgO content is preferably 35% by mass or more and the particle size is preferably 1 mm or less.
[0040]
Magnesium carbonate decomposes from around 600 ° C (MgCO_Three → MgO + CO₂ ) To generate fine voids in the construction body structure. In addition to absorbing and mitigating the expansion of the refractory, the fine voids prevent oversintering of the surface layer during use of the construction body and exhibit an excellent effect on structural spalling. From the viewpoint of corrosion resistance, the proportion of magnesium carbonate is more preferably 70% by mass or less of the entire magnesia raw material, or 10% by mass or less as a proportion of the entire refractory aggregate.
[0041]
The particle size of each of the alumina, spinel, and magnesia raw materials, which are main constituents of the present invention, is appropriately adjusted to coarse particles, medium particles, and fine particles in consideration of fluidity at the time of casting material construction or filling of the construction body.
[0042]
Volatile silica, meteorite, etc. can be used as the silica-based raw material. Volatile silica is added to alumina-magnesia amorphous refractories and basic amorphous refractories, and is effective for relaxation of expansion stress during spinel formation and suppression of magnesia hydration. Volatile silica is obtained, for example, as a by-product in the production of silicon or silicon alloys, and is marketed under a trade name such as silica flour or microsilica. Ultrafine particles with an average particle size of 1 μm. The blending ratio is preferably 3% by mass or less based on the entire refractory aggregate. When it exceeds 3 mass%, a low melting point substance will be produced | generated more and corrosion resistance will fall.
The most preferred range is 0.05 to 1.5 mass%.
[0043]
P₂ O_Five As the powder containing, those produced by an electrofusion method, a sintering method or the like can be used. P as before₂ O_Five In addition, this and Na₂ O and / or B₂ O_Three A total amount of 50% by mass or more is used. The particle size is desirably 100 μm or less.
[0044]
In addition, peptizers, refractory coarse particles, hardening modifiers, short metal fibers (for example, stainless steel fibers), organic fibers, ceramic fibers, carbon fibers, chromium ores, foaming agents, etc., known as additives for casting materials It may be added.
[0045]
In particular, the addition of peptizer is necessary to impart fluidity during construction. Specific examples include sodium tripolyphosphate, sodium hexametaphosphate, ultrapolyphosphate soda, acid hexametaphosphate soda, sodium borate, sodium citrate, carboxyl group-containing polyether dispersant, sodium tartrate, sodium polyacrylate, sulfone. There is acid soda. The addition ratio is preferably 0.01 to 0.5% by mass with respect to 100% by mass of the refractory aggregate.
You may add a boric acid, lithium carbonate, etc. as a hardening regulator. The addition amount is usually 0.5% by mass or less.
[0046]
The coarse refractory particles have an effect of preventing peeling damage by cutting off the development of cracks generated in the refractory structure. Specific examples are alumina, spinel, mullite, magnesia and the like. Further, brick scraps mainly composed of alumina or spinel, and products after using refractories may be used. The particle size of the refractory coarse particles is preferably 10 to 50 mm, although there is a balance with the maximum particle size of the refractory aggregate. In addition, the ratio is preferably 35% by mass or less, more preferably 5 to 30% by mass, based on 100% by mass of the refractory aggregate. If it exceeds 35% by mass, the strength of the construction body is inferior due to the poor balance of the particle size constitution, and the corrosion resistance is reduced.
[0047]
Each component in the refractory can be quantitatively analyzed by a fluorescent X-ray method using a glass bead sample. In general, carbon is oxidized by heating and analyzed as a gas.
[0048]
The refractory material of the present invention can be used as a casting material, and can also be used as a dry or wet spray material, plastic refractory material, patching material, stamp material, ramming material, sling material, coating material, mortar and the like. Adjust the amount and type of binders and additives as needed. The construction method may be as usual according to each type of refractory.
[0049]
In the case of a casting material, about 4 to 8% by mass of construction water is added to the entire blended composition as described above, and casting is performed using a mold such as a core. Moreover, it is good to improve a filling rate by giving a vibration at the time of pouring.
[0050]
【Example】
Examples of the present invention carried out with the casting material and comparative examples thereof are shown below. In each example, 6.5% by mass of working moisture was added to the entire composition shown in Tables 1 and 2 and kneaded, poured into a mold, applied, cured, and dried at 110 ° C. for 24 hours. A specimen was obtained. The amount of CaO in the table is a numerical value converted as the amount of CaO by multiplying the mass of each compound by the CaO concentration.
[0051]
In addition, calcined alumina manufactured by Showa Denko Co., Ltd. was used as the ultrafine alumina powder in each example. As the volatile silica, silica flour manufactured by Elchem Co., Ltd. was used. Aluminum lactate and aluminum glycolate are manufactured by Taki Chemical Co., Ltd. P₂ O_Five Each contained powder is P in mass%.₂ O_Five 60% Na₂ A material containing 20% O and having a particle size of 100 μm or less was used.
[0052]
The test method is as follows.
Corrosion resistance: Steel slab: converter slag (FeO content; 20% by mass) = 50: 50 was used as an erodant by mass ratio, and a erosion test was conducted at 1700 ° C. for 5 hours to measure a erosion dimension. Displayed with a melt index normalized to 100 for Comparative Example A11. The smaller the value, the higher the corrosion resistance and the better.
[0053]
Resistance to slag penetration; after performing a rotary erosion test under the above conditions, the slag penetration dimension was measured. The case of Comparative Example A11 was displayed as a slag penetration index normalized to 100. The smaller the value, the lighter and better the slag penetration.
[0054]
Spalling: Steel slab by mass ratio: Converter slag (FeO content; 20% by mass) = 50: 50 as an erodant, heated at 1700 ° C. for 30 minutes using a rotary erosion test apparatus, and then air-cooled for 30 minutes. This was repeated 6 times, and the occurrence of cracks was observed. ◎ indicates no crack, ◯ indicates a microcrack (with a width of about a hair crack that can be visually confirmed), △ indicates a small crack (a crack with a width of approximately 0.3 mm or less), and × indicates a large crack (with a width of approximately 0.00 mm). This shows that a crack of more than 3 mm has occurred.
[0055]
The room temperature bending test was measured as follows. That is, a sample was prepared by pouring into a 40 × 40 × 160 mm metal frame, dried, and then fired at 1000 ° C. for 3 hours in an air atmosphere before being subjected to a three-point bending test. The conditions were a span of 100 mm and a crosshead speed of 0.5 mm / min.
[0056]
In the hot bending test, a dried sample was used, heated in an argon atmosphere and held at 1400 ° C. for 15 minutes or more, and then measured by a three-point bending method at a span of 100 mm and a crosshead speed of 0.5 mm / min.
[0057]
  Table 1 shows examples of the present invention.(A01 to C01) and Reference Example (D01)Table 2 shows a comparative example. For easy comparison, alumina-magnesia is A, alumina-spinel is B, alumina-spinel-magnesia is C, magnesia-spinel is D, and the next is 0.And Reference Example (D01)1 was a comparative example.
[0058]
In the case of alumina-magnesia, A11 of the comparative example contains alumina cement and contains a large amount of CaO, so the melting index is large and the hot bending strength at 1400 ° C. is low. A12 of the comparative example in which no alumina cement is blended has good corrosion resistance, but has a low ordinary temperature bending strength after firing at 1000 ° C. On the other hand, A01 of the present invention is high in corrosion resistance, normal temperature bending strength after baking at 1000 ° C., and hot strength, and is less susceptible to spalling. P₂ O_Five It can be seen that excellent properties are exhibited even with A02 and A03 in which the addition amount of the contained powder is changed.
[0059]
The trend is the same in the case of alumina-spinel. That is, B11 of the comparative example contains alumina cement and has a large CaO, and thus has a large melting index. B12 of the comparative example which does not mix | blend an alumina cement has low normal temperature bending strength after 1000 degreeC baking. On the other hand, B01 of the present invention has good corrosion resistance and normal-temperature bending strength after baking at 1000 ° C., and it is good that spalling hardly occurs.
[0060]
The trend is the same in the case of alumina-spinel-magnesia. That is, C11 of the comparative example contains alumina cement and has a large amount of CaO, so the melting index is large and the hot bending strength is low. C12 of the comparative example which does not mix | blend an alumina cement has low normal temperature bending strength after 1000 degreeC baking. On the other hand, C01 of the present invention is excellent in corrosion resistance, normal temperature bending strength after baking at 1000 ° C. and hot bending strength, and is less susceptible to spalling.
[0061]
  In the case of magnesia-spinel, D11 of Comparative Example containing alumina cement and containing a large amount of CaO has a low hot bending strength and is likely to cause a spall. Comparative Example D12 containing no alumina cement has a low ordinary temperature bending strength after firing at 1000 ° C. P₂O₅D13 containing the contained powder and alumina cement had a high ordinary temperature bending strength after firing at 1000 ° C., but its hot bending strength was too low to be measured. It was also easy to spall.In addition, D01 of the reference example has large slag permeability as shown in Table 1, and the spalling property was inferior to the examples of the present invention.
[0062]
[Table 1]

[0063]
[Table 2]

[0064]
【The invention's effect】
As described above, according to the present invention, an amorphous refractory with high corrosion resistance and high strength can be obtained. Thereby, the lifetime of the refractory lining of various kilns can be extended, and the refractory cost and the manufacturing cost of steel can be reduced.

Claims (2)

P ₂ O ₅ is 0.1 to 3 wt%, CaO 0.5 wt% or less, SiO ₂ is 0.05 to 5 wt%, total amount of lactic acid and glycolic acid 0.005 wt%, the balance Is an amorphous refractory material of alumina-magnesia, alumina-spinel, or alumina-magnesia-spinel composed of Al ₂ O ₃ , MgO and other inevitable components, and by adding no alumina cement, CaO is 0.5 mass% or less,
The P ₂ O ₅ component is supplied by adding a P ₂ O ₅ -containing powder, and the P ₂ O ₅ -containing powder is further supplied with either a Na ₂ O component or a B ₂ O ₃ component. One or both are contained, and the content in the P ₂ O ₅ -containing powder is 10 to 70% by mass of P ₂ O ₅ , 10 to 30% by mass of Na ₂ O, and 5 to 60% by mass of B ₂ O _3. %, P ₂ O ₅ , Na ₂ O and B ₂ O ₃ is 50% by mass or more,
And, in a proportion of 100% by mass of the refractory aggregate composition, 3 to 15% by mass of alumina ultrafine powder having an average particle size of 1.5 μm or less, an iodine absorption of 20 iodine mg / g or more and an average particle size of 1 μm or less An amorphous refractory containing 0.01 to 3% by mass of light-burned magnesia fine powder.   Furthermore, as a pouring material, a peptizer, a refractory coarse particle, a curing regulator, a short metal fiber, an organic fiber, a ceramic fiber, a carbon fiber, chromium ore, and a foaming agent are added. Unspecified refractory as described.