JP3290818B2 - Alumina cement composition and amorphous refractory using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alumina cement composition, and more particularly, to an amorphous refractory containing a refractory aggregate such as magnesia, magnesia spinel, fused alumina, and sintered alumina. The present invention relates to an alumina cement composition having characteristics such as high fluidity, high strength development, corrosion resistance, and spalling resistance as compared with a composition, and an amorphous refractory using the same.

[0002]

2. Description of the Related Art Conventional alumina cement compositions
CaO / Al_TwoO_Three(Hereinafter referred to as CA) 50-80 weight
%, 12CaO ・ 7Al_TwoO_Three(Hereinafter C₁₂A₇5-30% by weight,
And 5-30% by weight of amorphous calcium aluminate
Consisting of α-Al_TwoO_Three, Hydroxycarboxylic acid, and none
Alumina cement composition containing carbonate
JP-A-50-28090, JP-A-49-32921, JP-A-50-1
No. 02617, and JP-A-55-121933, etc.)
Polyacrylic acid and / or methacrylic acid-acrylic
Alkaline containing a phosphoric acid copolymer and an alkali metal carbonate
Mina cement (JP-A-55-75947 and JP-A-55-75948)
Publication), CaO / Al_TwoO_ThreeCalcium salt with a ratio of 0.1 to 1
Alumina cement containing amorphous aluminate or C
A, CaO ・ 2Al_TwoO_Three(Hereinafter CA_Two3CaO ・ Al_TwoO_Three, C₁₂
A₇, And 11CaO ・ 7Al_TwoO_Three・ CaF_TwoCompatible with more than one composition such as
Al based on amorphous calcium aluminate
Mina cement (JP-A-61-132556, JP-A-61-77659)
JP, JP-A-2-75638, etc.)
At least 80% by weight of clinker and specific specific surface area
Alumina cement containing alumina and alumina cement
Al containing alumina fine powder in ment clinker
Mina cement (Japanese Patent Application Laid-Open No. 52-111920, Japanese Patent Application No. 43-74896)
Gazette), CA_TwoWith C as the subject₁₂A₇, Fine powder aluminum
And sulfonic acid-based anionic surfactant
Alumina cement (JP-A-55-144456, JP-A-55-144456)
-121934), and a specific proportion of CA and CA_TwoTo
Having clinker and α-Al _TwoO_ThreeAlumina cement consisting of
(USP 4162923) is known.

[0003] The basic characteristics of the mineral composition of alumina cement and the types of additives are also known (HIGH ALUMIN).
A CEMENTS AND CONCRETES. TD ROBSON 1962).

[0004] These alumina cements are intended to improve properties such as high strength development, high fire resistance and high fluidity, but if high strength developability is obtained, high fluidity cannot be obtained. However, if high fluidity is obtained, high strength expression cannot be obtained, and both have advantages and disadvantages, and do not deviate from the category of conventional products.If CA ₂ is contained as a mineral composition of clinker, hardening occurs. This was unfavorable as an alumina cement, for example, as a result of a delay and a decrease in strength development.

[0005] Further, when the content of Al ₂ O ₃ in the alumina cement is increased to improve the corrosion resistance and the fire resistance, the fluidity of the alumina cement decreases, and the curing strength and the drying strength tend to decrease significantly. Yes, Ca in alumina cement
The proportions of O and Al ₂ O ₃ were necessarily limited. The mineral composition of the conventional alumina cement has been limited to those mainly composed of CA in terms of securing fluidity and imparting strength.

[0006] curing rate adjustment of the CA, early those formulating hard calcium aluminate has been proposed (JP-B 44-4220 and JP like C ₁₂ A ₇ 54-139639
Issue publication). However, CA ₂ has a tendency to delay curing and decrease strength development, and C ₁₂ A ₇ has a feature of exhibiting rapid hardening. Even when the curing is adjusted with an additive or the like, CA ₂ or C ₁₂ A ₇
Was inferior to alumina cement mainly composed of CA in terms of strength development.

As described above, although many compositions of alumina cement are described in patents and literatures, the composition of alumina cement that is actually industrialized is limited to those mainly composed of CA, and hardening adjustment. It also contains C ₁₂ A ₇ , α-Al ₂ O ₃ , and various additives for the purpose of imparting high fire resistance and strength development, and contains clinker for ensuring high fire resistance. As a result of decreasing the CaO content, 5
Although there was some containing about ₂ % by weight or less of CA ₂ , there was no alumina cement that actively used CA ₂ as in the present invention.

At present, commercially available alumina cements such as "Hi-Alumina Cement Super", "Hi-Alumina Cement", "Alumina Cement No. 1", and "Alumina Cement No. 2" manufactured by Denki Kagaku Kogyo KK are available. "Asahi Alumina Cement No. 1" and "Asahi Fondue" manufactured by Asahi Glass Industry Co., Ltd., "Asano Alumina Cement No. 1" and "Asano Alumina Cement No. 2" manufactured by Nippon Cement, "CA25G" manufactured by Alcoa Lafarge brand names "Sekar 80" and "Sekar 71", such as "CA14", and "Union 1" and "Union H1" brand names from Union, as well as "Lum Knight" and "Refcon" from Lehigh And the like.

All of these products are mainly composed of CA and contain C ₁₂ A ₇ , α-Al ₂ O ₃ and additives according to required characteristics. CA ₂ is contained in a small amount, for example, 5% by weight or less. In addition, these products are characterized by fluidity, strength development, hardenability, and fire resistance, but are currently required in the refractory field, especially in the steel field including iron making equipment and steel making equipment. The required levels of amorphous refractories include fluidity,
There has been a problem that properties such as strength development, fire resistance, and corrosion resistance are insufficient. For this reason, a technique has been taken to cover the problems of these alumina cements by variously combining refractory aggregates constituting an amorphous refractory.

[0010] Further, it is necessary to mix a basic aggregate such as magnesia for the purpose of further improving the corrosion resistance to slag and metal, and the hardened body is digested by the kneading water, cracks are generated, and the aggregate is eluted from the aggregate. The soluble component that functions as a hardening accelerator for alumina cement, such as Mg ions, reduces the fluidity during kneading, shortens the pot life during construction, and causes troubles such as hardening in the mixer and hopper. There is a problem that the problem is easily generated. Especially for irregular refractories to be installed in places where high strength development, corrosion resistance, and spalling resistance are required, such as slag lines, ladle ladders, steel melted parts, repair in blast furnaces, etc. However, the conventional alumina cement has a problem in that the fluidity and strength development that are important in construction are insufficient.

[0011] Although the conventional alumina cement and known techniques are somewhat superior in improving the durability, a significant improvement in performance could not be expected.

In order to solve these problems, the present inventors have conducted various studies, and as a result, have found that the use of a specific alumina cement composition can solve the above-mentioned problems, thereby completing the present invention. .

[0013]

Means for Solving the Problems That is, the present invention is mineral composition is CA and CA _2, chemical composition CaO25~33 wt%
In the clinker is Al ₂ O ₃ 75~67% by weight, the Clean
Relative to the car 100 parts by weight, alumina cement composition comprising a C ₁₂ A ₇ containing calcium aluminate 0.1 parts by weight, the clinker, α-Al ₂ O _3, and 該Ku
0.1 to 1 based on a total of 100 parts by weight of the linker and α-Al ₂ O ₃
An alumina cement composition containing parts by weight of C ₁₂ A ₇ -containing calcium aluminate, and an amorphous refractory containing the alumina cement composition and a refractory aggregate.

Hereinafter, the present invention will be described in detail.

The clinker used in the present invention is composed of CA and CA ₂ as mineral composition, and its chemical component is CaO 25 to
33% by weight and is formed from Al ₂ O ₃ 75~67% by weight. In particular, in the present invention, it is important to balance the mineral composition and the chemical component ratio in this range.

Clinker is used for CaO such as limestone and quicklime.
Source and natural raw materials such as red bauxite and high purity alumina obtained by a refining method such as the Bayer process, and an Al ₂ O ₃ source such as bauxite are blended so as to have a predetermined component ratio, and an electric furnace and a reflection furnace. It is obtained by melting and / or firing in equipment such as a furnace, a vertical furnace, a flat furnace, a shaft kiln, or a rotary kiln. In the present invention, it is preferable to produce clinker by a firing method that facilitates producing the proportion of the calcium aluminate mineral within the object range of the present invention.

In order to obtain the mineral composition of the present invention, CA-CA
_There are a method of synthesizing the _two compositions at a time, and a method of blending the CA composition and the CA ₂ composition in a predetermined ratio.

The content ratio of the mineral composition in the present invention is Cu
It can be analyzed by X-ray diffraction analysis using -Kα radiation.
As a method of quantifying the mineral composition by the X-ray diffraction method, there are a diffraction ratio intensity ratio measuring method, an internal standard method, a Zevine method, an X-ray diffraction peak separation method, and the like. is there.

The method of measuring the intensity ratio of the diffraction line as used herein is a value that relatively expresses the diffraction intensity of each mineral. The internal standard method is a method in which an internal standard substance and a sample are mixed at a fixed ratio. This method is based on the fact that a linear relationship is obtained between the component concentration and the diffraction line intensity ratio, and a calibration curve is prepared and analyzed using a standard sample having a known concentration. The Zevine method is a method of measuring the average mass absorption coefficient of a sample and the diffraction line intensity ratio and quantifying each crystal phase by solving an n-order simultaneous equation. The average mass absorption coefficient is determined by X-ray fluorescence analysis. The components of the sample can be quantified and calculated by a method or chemical analysis.
In addition, it can be quantified by the X-ray diffraction peak separation method,
In this method, measurement is performed from the crystal or glass phase of a sample.

In the present invention, the mineral composition and the vitrification rate can be quantified by any of the methods. However, the measurement is simple and accurate, and the Zevine method or the diffraction ratio intensity measurement method can be used. The use of is preferred.

For example, the mineral composition ratio of the clinker of the present invention according to the Zevine method is preferably in the range of _{20 to} 90 parts by weight of CA and 80 to 10 parts by weight of CA ₂ , and particularly, 40 to 80 parts by weight of CA ₂ and CA 260 More preferably, it is in the range of 20 to 20 parts by weight. If the mineral composition ratio of the clinker is out of this range, fluidity, strength development, corrosion resistance, and spalling resistance tend to deteriorate.

Further, for example, mineral composition ratio of hydraulic substance alumina cement compositions of the present invention measured by the diffraction line intensity ratio, the diffraction intensity ratio of CA ₂ against diffraction line CA CA ₂
/ CA is preferably in the range of 0.1 to 10/1. In terms of the balance between fluidity, pot life, curability, and strength development when blended with an amorphous refractory, CA is preferred.
More preferably, ₂ / CA is in the range of 0.5 to 5/1. C
If A ₂ / CA is less than 0.1 / 1, high strength development and spalling resistance will deteriorate, and if it exceeds 10/1, fluidity and curability will tend to deteriorate. Here, the mineral composition ratio is the intensity ratio of the diffraction lines when d of CA is 4.67 ° and d of CA ₂ is 4.45 °.

The chemical component of the clinker of the present invention is CaO25
To 33% by weight, and Al ₂ O ₃ 75~67 wt%, CaO27～32 wt%, Al ₂ O ₃ 73~68% by weight. When the chemical component of the clinker is out of this range, the fluidity, strength development, corrosion resistance, and spalling resistance tend to deteriorate.

[0024] Alumina cement composition of the present invention, in addition to CA and CA ₂ of interest, due to the raw material α-Al ₂ O ₃
And those containing impurities such as 2CaO ・ Al ₂ O ₃・ SiO ₂ , CaO ・ TiO ₂ , and 4CaO ・ Al ₂ O ₃・ Fe ₂ O ₃ generated from impurities can be used. preferably better impurity less in the composition, SiO ₂ is 0.5 wt% or less, TiO ₂ is 0.5
% Or less, and Fe ₂ O ₃ is preferably 0.5% by weight or less. In particular, chemical components other than igros, CaO, and Al ₂ O ₃ are 0.1% by weight or less for each component, and less are used. preferable. A large amount of these impurities is not preferred because when used for an amorphous refractory, the volume change of the cured product at a high temperature becomes large, and the corrosion resistance to slag and the like decreases. Further, a small amount of unreacted CaO or Al ₂ O ₃ may be contained as long as the properties of the alumina cement composition are not impaired. Unreacted CaO is 2% by weight or less, and unreacted Al ₂ O ₃ is 10% or less.
% By weight or less, and 1.0% by weight or less of CaO, Al ₂ O ₃
Is more preferably 5.0% by weight or less. When unreacted raw materials are present in the clinker, Ca ions are eluted during kneading, and due to the presence of fillers, the flowability is deteriorated, the pot life is shortened, the curing is accelerated, and the strength is developed. There is a tendency that the stability is lowered or the volume stability at high temperature is deteriorated.

When clinker is produced by the firing method, CaO
The source and the Al ₂ O ₃ source are preferably mixed and / or mixed and ground at a predetermined ratio, and fired at a high temperature of 1,000 ° C. or more, more preferably 1,450 ° C. or more, in a rotary kiln. In the firing method, the particle size adjustment of the raw material, the firing temperature, and the firing time are important for obtaining a desired mineral composition.

When clinker is produced by a melting method, the Al ₂ O ₃ / CaO molar ratio is in the range of 2 to 6, and after melting,
Resulting mineral composition is an important that the CA-CA ₂ composition, since the component ratio of the mineral composition of CA and CA ₂ is a melting method is determined thermodynamically, CaO in the product 21.5～ Three
It is preferable to mix the raw materials so that 5.4% by weight and Al ₂ O ₃ are 78.5 to 64.6% by weight, and CaO is 25.0 to 33.0% by weight.
It is more preferable to mix the raw materials so that Al ₂ O ₃ has a component ratio of 75.0 to 67.0% by weight. The blended raw material is preferably melted at a high temperature of 1,500 ° C. or more, more preferably 1,700 ° C. or more by a melting apparatus such as an electric furnace or a flat furnace, and then cooled to high pressure air or water to obtain clinker.

In the present invention, a composition composed of CA and CA ₂ is synthesized at a time so as to obtain a desired mineral composition, or CA and CA ₂ are mixed at a predetermined compounding ratio, or the composition ratio is changed. It is also possible to combine clinkers made of different CA and CA ₂ so as to obtain a desired mineral composition ratio.

In the pulverization and mixing of these clinkers, the clinkers may be mixed and then pulverized, or each pulverized mixture may be mixed, and the means for obtaining the desired mineral composition ratio is particularly limited. Not something. As the clinker crusher, a crusher usually used for finely pulverizing a lump of powder can be used. For example, a roller mill, a jet mill, a tube mill, a ball mill, a vibration mill and the like can be used.

[0029] The vitrification rate of clinker is not particularly limited, but in general, the higher the vitrification rate, the higher the hydraulic property.
A high-strength cured product is obtained. The vitrification rate can be adjusted by a method of cooling the molten or fired high-temperature clinker. The degree of the vitrification ratio indicates that the lower the intensity of the diffraction line, the higher the vitrification ratio in the analysis of the mineral composition by the powder X-ray diffraction method.

The specific surface area of the clinker is an important property of the alumina cement. Fluidity, curability, and strength, because it is an important control point for obtaining the desired properties, the particle size of the pulverized clinker, the specific surface area by the Blaine method, 3,000 cm ² / g or more is preferable , more preferably at least 4,000cm ² / g, 4,500~8,000cm ² /
g is most preferred. If it is less than 3,000 cm ² / g, the strength decreases,
Liquidity may be reduced.

The average particle size is preferably finely pulverized to 10 μm or less, because of its excellent fluidity and high pot life, and more preferably 1 to 7 μm. If it is less than 1 μm, strength developability and fluidity tend to be reduced, and if it exceeds 7 μm, fluidity tends to be reduced and curing tends to be delayed.
The average particle size here is a value of a particle size measurement result by a generally used particle size distribution measuring device such as a laser diffraction method, a laser scattering method, or a sedimentation balance method, and
% Average diameter.

The C ₁₂ A ₇ -containing calcium aluminate (hereinafter referred to as C ₁₂ A ₇ -containing material) used in the present invention has a role of controlling the setting time and the pot life of the alumina cement composition containing the same. When no C ₁₂ A ₇ -containing material is mixed, curing at low temperatures is delayed, and the strength developability tends to be poor. C ₁₂ A A ₇ inclusions, C ₁₂ A ₇ alone is, of course, C ₁₂ A ₇ and CA mixing products, C ₁₂ A ₇ and CA and CA
₂ ml of a mixture, and shows the mixing Hinto of C ₁₂ A ₇ and CA _2.

In the present invention, it is important to combine the C ₁₂ A ₇ content with clinker and α-Al ₂ O ₃ . C ₁₂ A ₇
The inclusions can be obtained similarly to the clinker of the present invention. Further, the C ₁₂ A ₇ -CA composition, also C ₁₂ A ₇ -C
It can be obtained by a method of synthesizing the A-CA ₂ composition at a time, a method of mixing the C ₁₂ A ₇ composition, the CA composition and the CA ₂ composition in a predetermined ratio, or the like. The amount of the C ₁₂ A ₇ content is 100 parts by weight of clinker, or clinker and α-Al
100 parts by weight of the total of ₂ O _3, 0.1 to 1 parts by weight,
0.3 to 0.7 parts by weight is good Masui. If the amount is less than 0.1 part by weight, the curing tends to be delayed, and if it exceeds 1 part by weight, the fluidity tends to deteriorate.

The α-Al ₂ O ₃ used in the present invention is a purified alumina obtained by baking a highly purified aluminum hydroxide by a Bayer process or the like in a rotary kiln, wherein Al ₂ O ₃ is 90% by weight. % Of high-purity alumina, generally called high-purity alumina, Bayer alumina, easily sintered alumina, or light-burned alumina. In the present invention, α-Al ₂ O ₃ is effective for imparting high fire resistance, high-temperature strength development, and volume stability when the alumina cement composition of the present invention is used for an amorphous refractory. .

Further, depending on the type of α-Al ₂ O _{3 to be} compounded,
Since the characteristics of the alumina cement composition change greatly, α
The choice of -Al ₂ O ₃ is important. In particular, in the present invention,
Due to the interaction with the combined clinker, it is possible for the first time to exhibit characteristics not found in conventional products.The combined α-Al ₂ O ₃ has a primary particle diameter before pulverization with an average particle diameter (Dp50)
And the degree of firing is BET
Those having a specific surface area in the range of 0.5 to 100 m ² / g by the method are preferred. Usually, the primary particle size is related to the deposition rate of aluminum hydroxide in the Bayer process, and when the deposition rate is reduced, a large diameter is obtained, and when it is increased, a small diameter is obtained.

In the present invention, the primary particle size of α-Al ₂ O ₃ is 30 to
The firing degree of alumina was 60 μm, and the specific surface area of the BET method was 2
Preferably ~10m is ² / g, a primary particle size 40~50μ
More preferably, the specific surface area is in the range of 6 to 8 m ² / g. The degree of sintering indicates that the larger the specific surface area, the lighter the sintering type alumina. When used at a high temperature, the sintering property is excellent but the shrinkage is also large. When the specific surface area is large, the fluidity of the alumina cement composition is reduced, and when it is small, the fluidity tends to be improved. If the specific surface area is large, the sinterability at a high temperature is improved when blended with an amorphous refractory, but the oversintering tends to reduce the spalling resistance and increase the shrinkage. Those containing alumina having a small specific surface area show the opposite tendency.

For this reason, the selection of α-Al ₂ O ₃ used in the present invention should be carefully performed because it greatly affects the characteristics of the alumina cement composition, and the selection of the α-Al ₂ O ₃ when blended into an amorphous refractory is required. It should be decided appropriately according to the quality,
From the viewpoint of fluidity, curability, strength development, shrinkage, and spalling resistance, the primary particle diameter is 30 to 60 μm, and the degree of firing is ² to 10 m ² / g α-specific surface area of the BET method. The use of Al ₂ O ₃ is preferred.

Further, the purity of α-Al ₂ O ₃ can be determined by using Al ₂ O ₃ 9
Purity of 8% by weight or more can be secured. In the present invention, A
l ₂ O ₃ purity has never been high, but 98% by weight
That's enough.

In the present invention, in addition to the purity of Al ₂ O _{3, the} amount of Na ₂ O as an impurity is a problem. If the amount of Na ₂ O is large, the fluidity of the alumina cement composition is lowered, The amount of Na ₂ O is preferably small, preferably 0.5% by weight or less, and more preferably 0.35% by weight or less of a low sodium type, since fire resistance may decrease or shrink at high temperatures.

In the present invention, α-Al ₂ O ₃ and clinker are blended and mixed and pulverized by a pulverizer, or α-Al ₂ O ₃ alone is pulverized to a particle size equivalent to alumina cement, and then clinker pulverized. It is also possible to mix with things. When pulverizing α-Al ₂ O ₃ alone, it is preferable to pulverize Dp50 to about 1 to 10 μm. In the present invention, when α-Al ₂ O ₃ is mixed and pulverized with clinker, the affinity with the cement particles is better, and the α-Al ₂ O ₃ is uniformly mixed in the alumina cement composition. The body structure tends to be uniform and the corrosion resistance tends to be improved.

The mixing ratio of α-Al ₂ O ₃ is such that clinker and α-A
Preferably less than 30 parts by weight of the total 100 parts by weight of l ₂ O ₃
~ 25 parts by weight is more preferred. Increasing the blending ratio of α-Al ₂ O ₃ increases fire resistance and sintering strength at high temperatures, but tends to decrease curing strength and dry strength and fluidity. Although there is a balance with the composition, it is more preferable that the composition is adjusted so that the component ratio at the stage of mixing α-Al ₂ O ₃ becomes CaO 30 to 20% by weight and Al ₂ O ₃ 70 to 80% by weight. . In particular, in the present invention, CaO28
It is preferable that the content of 22% by weight, the content of Al ₂ O ₃ 〜72-78% by weight, and the balance be an impurity with igrosse, because of good flowability and high strength. When the alumina cement composition of the present invention is used for an amorphous refractory blended with magnesia aggregate, if there is a large amount of α-Al ₂ O ₃ in the alumina cement composition, the alumina cement composition reacts with magnesia at a high temperature and reacts with magnesia. In the process of producing spinel, α-Al ₂ in alumina cement composition to show volume expansion tendency
It is not preferable to mix O ₃ in a large amount so as to exceed 80% by weight, depending on the type and amount of the intended aggregate of the refractory. It should be noted that depending on the intended characteristics of the amorphous refractory using the alumina cement composition, it is not necessary to be trapped in this component range, and it is possible to change the mixing ratio fluidly.

The refractory aggregate used in the present invention may be any refractory aggregate used for irregular-shaped refractories. Specifically, molten magnesia, sintered magnesia, natural magnesia, And magnesia such as lightly burned magnesia, magnesia spinel such as fused magnesia spinel and sintered magnesia spinel, alumina such as fused alumina, sintered alumina, lightly fired alumina, and easily sintered alumina, silica fume, colloidal silica, lightly fired alumina And ultra-fine powders such as easily sintered alumina, fused silica, calcined mullite, chromium oxide, bauxite, andalusite, sillimanite, chamotte, silica stone, olivine, clay, zircon, zirconia, dolomite, perlite, vermiculite, brick Kudzu, pottery kudzu, silicon nitride, boron nitride, silicon carbide, and It is possible to use equalization silicon iron. Among these, from the viewpoint of corrosion resistance and fire resistance, it is preferable to use one or more types of refractory aggregates selected from magnesia, magnesia spinel, alumina, and ultrafine powder. Further, from the viewpoint of suppressing slag penetration, a combination of magnesia and alumina or a combination of magnesia spinel and alumina is preferable.

Here, magnesia refers to sintered magnesia obtained by calcining Mg (OH) ₂ , magnesia carbonate, magnesite which is natural magnesium oxide, or natural magnesia carbonate extracted from seawater by the seawater method using a rotary kiln or the like. Clinker, electrofused magnesia clinker obtained by melting the sintered magnesia clinker in an electric furnace or the like,
Or, when a sintered magnesia clinker and an electrofused magnesia clinker are crushed to a particle size of, for example, about 5 mm or less and sieved, and the MgO purity is 80% by weight or more when used as an amorphous refractory, It is preferable from the viewpoint of excellent corrosion resistance, and it is preferable that the content of impurities such as SiO ₂ and TiO ₂ is small, the purity of MgO is 95% by weight or more, and the content of CaO is 2%.
Magnesia having a content of not more than 0.5% by weight, a content of SiO ₂ of not more than 0.5% by weight and a content of B ₂ O ₃ of not more than 0.5% by weight are preferred from the viewpoint of excellent corrosion resistance. In addition, magnesia coated with spinel, magnesia containing magnesium titanate in grain boundaries, magnesia formed with calcium aluminate on the surface of magnesia particles, and high purity, high bulk density, and coarseness used in basic bricks Special magnesia clinker of crystal grains, and special magnesia such as magnesia-zirconia clinker with improved spalling resistance can also be used.

The magnesia spinel is obtained by mixing a MgO source such as magnesium hydroxide or calcined magnesia with an Al ₂ O ₃ source such as aluminum hydroxide or calcined alumina so as to have a predetermined ratio and using a rotary kiln. A spinel clinker obtained by reacting and sintering at a temperature of about 1,800 to 1,900 ° C. using a firing apparatus such as the above, and a molten magnesia spinel melted by a melting apparatus such as an electric furnace is crushed to a predetermined size and sieved. These include those obtained by dividing, and those obtained by mixing the baked and melted products.

The weight ratio of MgO / Al ₂ O ₃ of the magnesia clinker is preferably from 1/1 to 0.1 / 1, and from 0.4 / 1 to 0.2 / 1.
Is more preferable from the viewpoint of excellent durability when blended with an amorphous refractory.

Alumina is obtained by firing and / or melting an Al ₂ O ₃ source such as aluminum hydroxide or calcined alumina by a firing device such as a rotary kiln or a melting device such as an electric furnace. It is crushed to size and sieved, and the mineral composition is α-Al ₂ O ₃ or β
-Al ₂ O ₃ is an aluminum oxide that is referred to as sintered alumina, calcined alumina, easily sintered alumina, and the like, and usually contains α-Al ₂ O _{3 in an amount} of 90% by weight or more. The use of Al ₂ O ₃ is most preferred. It is also possible to use alumina / zirconia clinker having improved spalling resistance, which is obtained by melting alumina and zirconia clinker.

The particle size of the refractory aggregate, usually 5 to 3 mm,
Those having a size of 3 to 1 mm, 1 mm lower, 200 mesh lower, 325 mesh lower, or the like can be blended according to required physical properties.

In the present invention, as the refractory aggregate, it is possible to use ultrafine powder having a fine particle diameter.

Here, the ultrafine powder is a refractory fine powder occupying 80% by weight or more of particles having a particle diameter of 10 μm or less, having an average particle diameter of 1 μm or less and having a specific surface area of 10 m ² / g or more by a BET method. These are preferred because when blended into an amorphous refractory, they can ensure fluidity and have high strength. In particular,
Silica fume, colloidal silica, easily sintered alumina,
Inorganic fine powders such as amorphous silica, zircon, silicon carbide, silicon nitride, chromium oxide, and titanium oxide can be used, and among them, silica fume, colloidal silica, and easily sintered alumina are preferably used.

The mixing ratio of the amorphous refractory of the present invention should be appropriately determined depending on the construction site, and is not particularly limited. However, the weight of the amorphous refractory consisting of the alumina cement composition and the refractory aggregate is 100% by weight. Middle part, fire-resistant aggregate 99.5-50
Parts by weight, and preferably 98 to 85 parts by weight from the viewpoints of corrosion resistance and strength development. If the refractory aggregate is out of this range, the fluidity, strength development, corrosion resistance, and spalling resistance tend to deteriorate. The particle size adjustment of the refractory aggregate is determined by the target physical properties of the amorphous refractory, and is not particularly limited.In 100 parts by weight of the amorphous refractory, the alumina cement composition contains 2 to 2 parts. 5 to 20 parts by weight of sintered magnesia having a particle size of 1 mm or less and a balance of 1 to 10 mm in diameter using fused alumina and / or sintered alumina. ~ 15 parts by weight, magnesia spinel with a particle size of 1 mm or less
Fused alumina having a particle size of 1 to 10 mm and / or
Alternatively, a material using sintered alumina is preferable because of good fluidity, high strength development, and little erosion by slag.

Although the method for producing the amorphous refractory of the present invention is not particularly limited, each material is blended so as to have a predetermined ratio in accordance with the usual method for producing an irregular refractory.
Mix uniformly using a mixer such as a V-type blender, cone blender, Nauta mixer, bread mixer, omni mixer, or, when kneading at a predetermined ratio, directly weigh into the kneading machine and mix. It is also possible.

In the present invention, citric acid, gluconic acid, tartaric acid, malic acid, and salicylic acid, or a hydroxycarboxylic acid such as a sodium salt, a potassium salt, and a calcium salt thereof, or a polyacrylic acid or a salt thereof. One or more organic acids selected from the group consisting of a salt, polymethacrylic acid or a salt thereof, and a methacrylic acid-acrylic acid copolymer or a salt thereof can be appropriately used. The amount of the organic acid used is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the alumina cement composition. If the amount is less than 0.1 part by weight, the workability tends to decrease, and 1
If the amount exceeds 0 parts by weight, curing tends to be delayed.

Also, K ₂ CO ₃ , Na ₂ CO ₃ , KHCO ₃ , and NaHCO ₃
And the like, sodium tripolyphosphate, sodium hexametaphosphate, sodium acid hexametaphosphate, aluminum phosphate, sodium borate, and one or more inorganic salts appropriately selected from the group consisting of boric acid and the like. It is possible to The amount of inorganic salt used is
0.1 to 10 parts by weight is preferable for 100 parts by weight of the alumina cement. If the amount is less than 0.1 part by weight, the workability tends to decrease, and if it exceeds 10 parts by weight, the curing tends to be delayed.

[0054]

The present invention will be further described below with reference to examples.

Example 1 Clinker, α-Al ₂ O ₃ (alumina), C
_As shown in Table 2, ₁₂ A ₇ , CA and CA ₂ were blended so that the amount of CaO in the alumina cement composition was about 25% by weight, and pulverized with a vibration ball mill to prepare an alumina cement composition. . 80 parts by weight of the refractory aggregate was mixed with 20 parts by weight of this alumina cement composition, and kneaded at a water / (alumina cement composition + refractory aggregate) ratio of 9% to produce an irregular-shaped refractory. 20 ° C flow value I and heat generation time I of this amorphous refractory, and 30 ° C flow value II and heat generation time
II was measured. The results are also shown in Table 2.

<Materials Used> Clinker: A commercially available high-purity calcium carbonate is used as a CaO raw material, and a commercially available high-purity alumina is used as an Al ₂ O ₃ raw material, so that the mineral composition in the product is a predetermined ratio. Table 1 shows each type of clinker that was blended in the above-described manner, calcined at 1,400 to 1,500 ° C. in a kiln, and calcined. Alumina: α-Al ₂ O _3, commercially available products C ₁₂ A ₇ inclusions I: Commercially available high-purity calcium carbonate as CaO raw material, using a commercially available high-purity alumina as Al ₂ O ₃ raw material, the product formulated as mineral composition is C ₁₂ a _7, it fired kiln at 1,400 to 1,600 ° C., the main component C ₁₂
A ₇ C ₁₂ A ₇ content b: Similarly, the mineral composition in the product is C ₁₂
Firing formulated such that A ₇ and CA, C ₁₂ A ₇ / weight ratio 50/50 C ₁₂ A ₇ content of CA Ha: Similarly, mineral composition in the product is C ₁₂
Blended and blended to A ₇ , CA and CA ₂ , C ₁₂ A
₇ / CA / CA ₂ weight ratio of 30/40/30 refractory aggregate α: sintered alumina, manufactured by Showa Denko KK, particle size 3,360
~ 1,190μ27 parts by weight, 1,190 ~ 590μ16 parts by weight, 590 ~ 297
A mixture of 16 parts by weight, 14 parts by weight under 297 μ, and 7 parts by weight under 44 μ

<Measurement method> Chemical components: CaO and Al ₂ O ₃ are analyzed according to JIS R 2522. Mineral composition: X-ray diffraction analyzer “RADIIB” manufactured by Rigaku Corporation.
Diffraction intensity ratio, d value, CA = 4.67 °, CA ₂ = 4.45
Å, C ₁₂ A ₇ intensity flow value of diffraction lines: JIS according to R 2521, to smooth the surface stuffed monolithic refractory therein Place the flow cone in place of the central flow table. Next, the flow cone is removed upward, and the diameter of the longest-recognized diameter of the irregular-shaped refractory and the diameter in two directions of the diameter perpendicular thereto are measured, and the average value is displayed in the unit of mm. Place the poly-beaker containing the refractory material in an insulated container, insert the RTD, measure the heating time with a recorder, measure the time from the start of kneading until the heating curve reaches the peak heating time.

[0058]

[Table 1]

[0059]

[Table 2]

Example 2 Using clinker C, a total of clinker and α-Al ₂ O ₃ of 10
The procedure was performed in the same manner as in Example 1 except that the content of C ₁₂ A ₇ was 0.6 parts by weight with respect to 0 parts by weight, and the amounts of clinker and α-Al ₂ O ₃ used were changed as shown in Table 3. . The results are also shown in Table 3.

[0061]

[Table 3]

[0062] Example 3 clinker C80 parts, alpha-Al ₂ O ₃ 20 parts by weight, and blending the C ₁₂ A ₇ inclusions B 0.6 parts by weight based on 100 parts by weight of the clinker and alpha-Al ₂ O ₃ An alumina cement composition was prepared. The procedure was performed in the same manner as in Example 1 except that the alumina cement composition was mixed with various types of refractory aggregates shown in Table 4 in 100 parts by weight of the total of the alumina cement composition and the refractory aggregate. The results are also shown in Table 4.

<Materials Used> Refractory aggregate β: particle size 3,360 to 1,190 μ28 parts by weight, 1,190 to 590
A mixture of 15 parts by weight, 590 to 297 μ16 parts by weight, and 15 parts by weight under 297 μm of commercially available Otabi chamotte and 7 parts by weight of 44 μm under sintered alumina manufactured by Showa Denko Corporation Fire-resistant aggregate γ: particle size 3,360 to 1,190 μ30 parts by weight , 1,190-590
μ15 parts by weight, 590 to 297μ15 parts by weight, and 297μ below 15 parts by weight of Sumitomo Chemical Spinel and 44μ under 5 parts by weight Showa Denko Sintered Alumina

[0064]

[Table 4]

Example 4 80 parts by weight of clinker C, α-Al_TwoO_Three20 parts by weight, clinker
ー and α-Al_TwoO_ThreeFor a total of 100 parts by weight of₁₂A₇Inclusions
0.6 parts by weight, and clinker, α-Al_TwoO_Three, And C ₁₂A₇Including
The organic acid salt is shown in Table 5 with respect to the total of 100 parts by weight.
And pulverized using a vibrating mill to obtain alumina
Same as Example 1 except that a cement composition was prepared
I went to. The results are also shown in Table 5.

<Materials Used> Organic acid salt a: sodium polyacrylate, manufactured by Nippon Pure Chemical Co., Ltd. Organic salt b: sodium polymethacrylate, manufactured by Nippon Pure Chemical Co., Ltd. Organic acid salt c: sodium citrate, manufactured by Ishizu Pharmaceutical Co., Ltd. Primary reagent Organic salt d: sodium polyacrylate / sodium citrate weight ratio 1 / 0.6 Organic salt e: polysodium methacrylate / sodium citrate weight ratio 1 / 0.3 Organic salt f: sodium polyacrylate / polymethacryl Sodium citrate / sodium citrate weight ratio 0.5 / 1 /
0.4

[0067]

[Table 5]

Example 5 The procedure of Example 4 was repeated, except that an inorganic salt was used instead of the organic acid salt as shown in Table 6. The results are also shown in Table 6.

<Materials Used> Inorganic salt: sodium carbonate, first-class reagent manufactured by Ishizu Pharmaceutical Inorganic salt: sodium hexametaphosphate, first-class reagent manufactured by Ishizu Pharmaceutical Inorganic salt: sodium carbonate / sodium hexametaphosphate weight ratio 0.5 / 1.2

[0070]

[Table 6]

Example 6 80 parts by weight of clinker C, α-Al_TwoO_Three20 parts by weight, clinker
ー and α-Al_TwoO_ThreeFor a total of 100 parts by weight of₁₂A₇Inclusions
0.6 parts by weight, and clinker, α-Al_TwoO_Three, And C ₁₂A₇Including
As shown in Table 7, the total of 100 parts by weight
Except that 1 part by weight of the acid salt and 0.7 part by weight of the inorganic salt were used.
Performed in the same manner as in Example 4. The results are also shown in Table 7.

[0072]

[Table 7]

Example 7 Using the irregular-shaped refractory produced in Example 1, 4 × 4 × 16
A cm test piece was molded, and the curing strength, drying strength, and firing strength were measured. Table 8 shows the results.

<Measurement method> Curing strength: In conformity with JIS R 2553, 4 x irregular shaped refractories
Cast into a 4 × 16 cm formwork, smoothen the surface with a cement knife, and strength after curing for 24 hours. Dry strength: Dry the specimen after curing for 24 hours at 110 ° C. for 24 hours and then to room temperature. Allow to cool and measure the strength. Firing strength: The dried specimen is subjected to a siliconite electric furnace.
After raising the temperature to 800, 1,000, 1,200, 1,400 ° C, hold it for 2 hours, let it cool down to room temperature, and measure the strength

[0075]

[Table 8]

Example 8 Using clinker C, the total amount of clinker and α-Al ₂ O ₃ was 10
The procedure was performed in the same manner as in Example 7 except that the content of C ₁₂ A ₇ was 0.6 parts by weight with respect to 0 parts by weight, and the amounts of clinker and α-Al ₂ O ₃ used were changed as shown in Table 9. . The results are also shown in Table 9.

[0077]

[Table 9]

[0078] Example 9 clinker C80 parts, α- Al ₂ O ₃ 20 parts by weight, and blending the C ₁₂ A ₇ inclusions B 0.6 parts by weight based on 100 parts by weight of the clinker and α-Al ₂ O ₃ An alumina cement composition was prepared. For 20 parts by weight of this alumina cement composition,
Example 7 was repeated except that 80 parts by weight of various refractory aggregates were blended. Table 10 shows the results.

[0079]

[Table 10]

Example 10 For 100 parts by weight of the clinker C formulation, Table 11
Example 7 was carried out in the same manner as in Example 7, except that the organic acid salt and the inorganic salt were blended as described above and pulverized using a vibration mill to prepare an alumina cement composition. The results are shown in Table 11. Clinker C80 parts, α- Al ₂ O ₃ 20 parts by weight, per 100 parts by weight of the total of the clinker and _{α-Al 2 O 3, C} 12 A 7 inclusions B 0.6 parts by weight, and clinker, alpha-Al ₂ O ₃ and C
Per 100 parts by weight of the total of ₁₂ A ₇ inclusions, as shown in Table 10, except for using an organic acid salt and inorganic salt was performed in the same manner as in Example 7. The results are shown in Table 11.

[0081]

[Table 11]

Example 11 Using the irregular shaped refractory prepared in Example 1, 4 × 4 × 16 cm
Specimens were formed, and holes of φ2 × 2 cm were drilled according to JIS R 2214, slag was put in them, and
It was kept at 500 ° C. for 2 hours, and then cooled naturally. After cooling,
The area of the portion that was bisected from the center of the hole, eroded and dissolved was measured. Table 12 shows the results. In the same manner, a specimen is formed, and kept at 1,500 ° C. for 3 hours in a siliconit furnace according to JRS 2118 of the Japan Refractory Technology Association, and then naturally cooled. This heating-cooling operation was repeated, and the number of cracks was measured. The results are shown in Table 12.

[0083]

[Table 12]

[0084]

As described above, when the alumina cement composition of the present invention is used, amorphous refractories having high fluidity, high strength development, corrosion resistance, spalling resistance and the like are excellent as compared with conventional ones. It has effects such as being obtained.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 7/32 C04B 22/08 C04B 28/06

Claims (3)

(57) [Claims] 1. A mineral composition is CaO · Al ₂ O ₃ and CaO · 2Al ₂ O _3, the chemical components CaO25~33 wt%, Al ₂ O ₃ 75~67 wt%
And 100 parts by weight of the clinker
An alumina cement composition comprising 0.1 to 1 part by weight of 12CaO · 7Al ₂ O ₃ -containing calcium aluminate. 2. A mineral composition is CaO · Al ₂ O ₃ and CaO · 2Al ₂ O _3, the chemical components CaO25~33 wt%, Al ₂ O ₃ from 75 to 67 wt%
Clinker, α-Al ₂ O ₃ , the clinker and α-A
100 parts by weight of the total of l ₂ O _3, 12CaO · 0.1 to 1 parts by weight
An alumina cement composition containing 7Al ₂ O ₃ -containing calcium aluminate. 3. An amorphous refractory comprising the alumina cement composition according to claim 1 and a refractory aggregate.