JPH1025136A - Alumina cement, alumina cement composition and amorphous refractory material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a proper pot life, high strength development, high fluidity, high corrosion resistance and abrasion resistance by mixing a hydraulic component comprising a specific mineral component and chemical components into an alumina cement. SOLUTION: The hydraulic substance to be used here has a mineral composition of CaO.Al2 O3 (CA), CaO.2Al2 O3 (CA2 ) and 12CaO.7Al2 O3 (C12 O7 ) and the content of C12 A7 is 5-15wt.% in the mineral constitution, while the content of CaO is 20-40wt.% in the total of CaO and Al2 O3 in the chemical components. Particularly, C12 O7 is 5wt.%<=C12 O7 <=14wt.%, more preferably 5wt.%<=C12 O7 <=10 wt.% in the mineral components. It is important for the composition of the specific mineral components to be compatible with that of the chemical components. This alumina cement contains the above-described hydraulic substance and alumina (Al2 O3 content, >=90wt.%, the primary particle size, 20-100μm before crushing) and the α-alumina content is 5-80 pts.wt. based on 100 pts.wt. of the total of the hydraulic substance and α-alumina.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an alumina cement, an alumina cement composition, and an amorphous refractory, particularly an alumina cement having high strength, high fluidity, high corrosion resistance and abrasion resistance not found in conventional products. , An alumina cement composition, and an amorphous refractory. The alumina cement, the alumina cement composition, and the amorphous refractory of the present invention can be used in the field of refractories in which alumina cement is used, linings of chemical plants, corrosion-resistant materials, and the like.

[0002]

[Prior art and its problems] Conventionally, a specific proportion of CaO.Al_TwoO
_Three, 12CaO ・ 7Al_TwoO_Three, And amorphous, α-aluminum
Na, hydroxycarboxylic acid, and inorganic carbonate
Alumina cement composition, water-soluble polyacrylic
Acids and / or methacrylic acid-acrylic acid copolymer;
Alumina cement containing alkali metal carbonate
G, specific CaO / Al_TwoO_ThreeAmorphous calcium al with a ratio
Contains minate (amorphous calcium aluminate)
Alumina cement, CaO / Al_TwoO_Three, CaO2Al_TwoO_Three, 3CaO
・ Al_TwoO _Three , 12CaO ・ 7Al_TwoO_Three, And 11CaO7Al_TwoO_Three・ CaF_Two
Amorphous calcium corresponding to one or more mineral compositions such as
Alumina cement mainly composed of calcium aluminate,
Calcium aluminate composition of at least 80% by weight or more
Clinker and alumina with specific surface area
Alumina cement containing
Alumina cement containing fine alumina powder
And CaO ・ 2Al_TwoO_ThreeMainly 12CaO ・ 7Al
_TwoO_Three, Finely divided alumina, and sulfonic acid-based anionic surfactant
Alumina cement containing a surfactant is proposed.
(JP-A-49-32921, JP-A-50-102617)
And JP-A-55-121933.
JP-A-61-132556
JP-A-61-77659, JP-A-2-1756
No. 38, such as JP-A-52-111920 and JP-B-47-406.
No. 94, etc., as well as JP-A-55-121934 and JP-A
No. 55-144456, etc.). In addition, alumina cement
Basic properties on mineral composition and types of additives have also been proposed.
(HIGH ALUMINA CEMENT AND CONCRETES; T.D.ROB
SON 1962).

[0003] The alumina cements described in these patents and documents are aimed at improving properties such as high strength development, high fire resistance and high fluidity, but each has advantages and disadvantages. Did not deviate from the category of commercially available products. In particular, when the Al ₂ O ₃ content in the alumina cement is increased to improve the corrosion resistance and fire resistance, there is a problem that the curing strength and the drying strength are remarkably reduced, and CaO and Al ₂ O ₃ Was necessarily limited. In addition, the mineral composition of many alumina cements, regardless of the type of calcium aluminate and the proportion of calcium aluminate, is to ensure fluidity, to provide strength development and to ensure appropriate curability. , Ca
It was limited to those mainly composed of O ₂ Al ₂ O ₃ .

[0004] On the other hand, it has been proposed to mix a fast-curing calcium aluminate such as 12CaO · 7Al ₂ O _{3 to} adjust the curing rate of calcium aluminate (Japanese Patent Application Laid-Open (JP-A) no.
54-139637). However, CaO 2Al ₂ O ₃ and 3C
aO · 5Al ₂ O ₃ showed a tendency to decrease curing retardant properties and strength _{development, 12CaO · 7Al 2 O 3,} 5CaO · 3Al 2 O 3, and 3CaO · Al ₂ O
No. ₃ has a feature of exhibiting rapid hardening property, and there is a problem that even if the hardening is adjusted by an additive or the like, the alumina cement mainly composed of CaO.Al ₂ O ₃ is inferior in terms of strength development.

[0005] As described above, the technique related to alumina cement is used.
Although there are many patents that describe techniques,
Alumina cement has a mineral composition of CaO
・ Al _TwoO_ThreeIs limited to those mainly composed of
For the purpose of air conditioning and for imparting high fire resistance and strength
And 12CaO 7Al_TwoO_Three, Α-alumina, and various additives
It contained.

[0006] Each of these has characteristics such as fluidity, strength development, curability, and fire resistance.
Properties such as fluidity, strength development, fire resistance, and corrosion resistance were insufficient for the required level of irregular refractories required in the refractory field, particularly in ironmaking facilities and steelmaking facilities. In particular, work in places where high strength development, corrosion resistance, abrasion resistance, spalling resistance, etc. are required, such as slag lines and ladle laying parts, steel bath parts, repair in blast furnaces, etc. Conventional alumina cement lacks fluidity and strength development in amorphous refractories, and a certain amount of alumina cement is required.The amount of CaO in amorphous refractories derived from the amount of alumina cement used is It could not be reduced. In order to improve durability, it is essential to reduce the amount of CaO in amorphous refractories.For this reason, conventional alumina cement and known technologies have some advantages, but significant performance improvements can be expected. Did not.

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, an alumina cement containing a hydraulic substance having a specific mineral composition and a chemical component is excellent in high strength development and fluidity, The inventors have found that a suitable pot life and curability can be obtained, and have completed the present invention.

[0008]

Means for Solving the Problems That is, the present invention provides CaO.
_{Al 2 O 3, CaO · 2Al} 2 O 3, and it contains a mineral composition of _{12CaO · 7Al 2 O 3, 12CaO} · 7Al 2 O 3 in the mineral composition is from 5 to 15
% By weight, and CaO in the total of the chemical components CaO and Al ₂ O ₃
Is an alumina cement containing a hydraulic substance of 20 to 40% by weight, comprising the hydraulic substance and α-alumina, wherein α-alumina is formed of a hydraulic substance and α-alumina. A total of 100 parts by weight of the alumina cement is 5 to 80 parts by weight, the alumina cement, carboxylic acids, carbonates, polyacrylic acids, polymethacrylic acids,
An alumina cement composition comprising an acrylic acid-methacrylic acid copolymer and one or more additives selected from the group consisting of boric acids, wherein the alumina cement or the alumina cement composition is refractory. It is an irregular-shaped refractory containing an aggregate.

Hereinafter, the present invention will be described in detail.

The hydraulic substance used in the present invention is CaO.Al
₂ O ₃ (CA), CaO 2Al ₂ O ₃ (CA ₂ ), and 12CaO 7Al ₂ O ₃ (C
₁₂ A ₇ ), and contains C ₁₂ A ₇
There is a 5 to 15 wt%, CaO in total in CaO and Al ₂ O ₃ chemical component is 20 to 40 wt%. In particular, C in mineral composition
₁₂ A ₇ is preferably at least 5% by weight and less than 14% by weight,
0% by weight is more preferred, and it is important to balance this particular mineral composition with the chemical composition. Hydraulic substances are
If the mineral composition and the chemical component are out of the ranges described above, it is difficult to obtain the necessary high strength.

Hydraulic substances include CaO such as limestone and quicklime.
The raw material and Al ₂ O ₃ raw material of high purity alumina and bauxite or the like obtained was purified by purification of a natural material buyers process or the like for red bauxite, etc., and formulated to a predetermined component ratio, electrical Clinker obtained by melting and / or firing in equipment such as a furnace, a reverberatory furnace, a vertical furnace, a flat furnace, a shaft kiln, and a rotary kiln is crushed. In particular, in the present invention, compared to the hydraulic substance produced by the melting method, the hydraulic substance produced by the sintering method, the generation ratio of the calcium aluminate mineral composition is easy to produce within the scope of the present invention It is preferable from the viewpoint.
That is, thermodynamically, CA, CA _2, and the three mineral composition of C ₁₂ A ₇ is present in one of the melt is not possible, therefore, to obtain the mineral composition of the present invention, CA- CA ₂ and CA-C ₁₂
The mineral composition of the two-component A _7, or, CA, CA _2, and C ₁₂
Must blended single mineral composition of A ₇ to a predetermined ratio, mineral composition of hydraulic substance is difficult to obtain in the melting method.
On the other hand, in the firing method, the formation of calcium aluminate is mainly based on the diffusion reaction of Al ₂ O ₃ into CaO, so that a plurality of thermodynamically adjacent mineral compositions can be obtained, and the desired chemical components It is an advantage of the firing method that the ratio is easily manufactured. Specifically, the predetermined present invention CA-CA ₂ -
C ₁₂ A ₇ based mineral composition is obtained by one time of firing.
When producing a hydraulic substance by the firing method, the hydraulic substance is Ca
O raw material and Al ₂ O ₃ raw material are mixed at a predetermined ratio, or mixed and pulverized, or after partial mixing, further mixed and pulverized, for example, using a rotary kiln to 1,000 to 1,600.
It is obtained by pulverizing clinker obtained by firing at a temperature of ° C. The particle size adjustment of the raw material, the firing temperature, the firing time, and the cooling rate are control points for obtaining a predetermined mineral composition. When the unreacted raw material is present in the hydraulic substance, there is a tendency that fluidity is deteriorated, strength developability is reduced, and volume stability at high temperature is poor.

In the present invention, to other types of mineral composition, these mineral compositions, CA, CA _2, and C ₁₂ A ₇ to contain a specific ratio that is significant. The content of these mineral composition (mineral composition ratio) is a possible analysis by X-ray diffraction, each mineral composition ratio, for example, CA 30 to 80% by weight, CA ₂ 5 to 45 wt%, and C ₁₂ A ₇ is 5 to 15 wt%
It is preferable to produce a hydraulic substance so that Moreover, strength development, the content of C ₁₂ A ₇ in terms of the balance of flowability and curability, 5 wt% or more, more preferably less than 14 wt%, and most preferably 5 to 10 wt%. 5% by weight
If the amount is less than 15%, the curing retardation and strength developability tend to decrease. If the amount exceeds 15% by weight, fluidity cannot be obtained and the pot life tends to be short. In addition, as the hydraulic substance, a predetermined,
CA, CA _2, and C ₁₂ in addition to the mineral composition of A _7, further generated by impurities mixed from raw _{materials, 2CaO · Al 2 O 3 ·} Si
O _2, CaO · TiO _2, and _{4CaO · Al 2 O 3 · Fe} 2 those containing mineral composition represented as O ₃ or the like can be used.

Further, the chemical components of hydraulic substances, CaO and Al
Total in ₂ O _3, CaO is important that 20 to 40 wt%, and more preferably CaO is 24 to 32 wt%.
When CaO exceeds 40% by weight, C ₁₂ A ₇ , 3CaO · Al ₂ O ₃ (C ₃ A),
And a hard mineral composition such as 5CaO.3Al ₂ O ₃ (C ₅ A ₃ ) is likely to be generated, the fluidity cannot be obtained, and the pot life becomes short. If CaO is less than 20% by weight, CA ₂ , C ₃
A _5, and mineral composition of the curable delayed or non-hydraulic of α- alumina unreacted is easily generated, there is a tendency that curing delay property and development of strength is undesirably reduced. It is also possible to contain a small amount of unreacted CaO or unreacted Al ₂ O ₃ as long as the properties of the hydraulic substance are not impaired. Unreacted CaO
Is 2% by weight or less, and unreacted Al ₂ O ₃ is 20% by weight.
The following degree is preferable.

The degree of vitrification of the hydraulic substance is not particularly limited, but in general, a high vitrification rate increases the hydraulic property, and a high-strength cured product is obtained. The vitrification rate can be adjusted by cooling the molten and / or calcined high-temperature clinker, and the rapid vitrification increases the vitrification rate. This vitrification ratio can be measured by analyzing the mineral composition by powder X-ray diffraction, and the degree indicates that the lower the diffraction line intensity, the greater the vitrification ratio.

For the pulverization of clinker, it is possible to use a pulverizer, such as a roller mill, a jet mill, a tube mill, a ball mill, and a vibrating mill, which is usually used for finely pulverizing a lump of powder. The clinker is pulverized by these pulverizers until the Blaine specific surface area becomes preferably 3,000 cm ² / g or more, more preferably 4,000 cm ² / g or more. The brane specific surface area of a hydraulic substance is related to fluidity, curability, and strength development, which are important properties of the hydraulic substance, and is an important control point for obtaining required properties, and is 4,500 to 6,000 cm. ² / g is most preferred.

The α-alumina used in the present invention is an alumina cement which is blended with a hydraulic substance to give high fire resistance, high-temperature strength development, and volume stability. A purified alumina obtained by calcining a highly purified aluminum hydroxide by a rotary kiln or the like, and is generally referred to as high-purity alumina, Bayer alumina, easily sintered alumina, light-burned alumina, or the like. . The purity of α-alumina is
If the alumina is produced by a usual buyer process, a purity of about 90% by weight or more of Al ₂ O ₃ can be secured, and 98% by weight or more is more preferable. The higher the purity of Al ₂ O _3, the better, but 90% by weight or more is sufficient. The selection of α-alumina is important because the characteristics of the alumina cement or alumina cement composition greatly change depending on the type of α-alumina to be blended. The particle size of α-alumina, the primary particle size before grinding is the average particle size (Dp50)
About 20 to 100 μm, preferably 30 to 60 μm, more preferably 40 to 50 μm. If it is less than 20 μm, the fluidity tends to decrease, and if it exceeds 100 μm, the sintering strength when used for an amorphous refractory tends to decrease. Also, α
-The degree of calcination of alumina is 0.5 as a specific surface area by the BET method.
100100 m ² / g is preferred, 2 to 10 m ² / g is more preferred, and 6
~ ⁸ m2 / g is most preferred. Normally, the primary particle diameter is related to the precipitation rate of aluminum hydroxide in the Bayer process. When the precipitation rate is reduced, a particle having a large particle diameter is obtained, and when the precipitation rate is increased, a particle having a small particle diameter is obtained.
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. If the specific surface area of α-alumina is large, the fluidity of the alumina cement decreases, and if it is small, the fluidity tends to improve. 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. In the case where α-alumina having a small specific surface area is blended, shrinkage tends to be small and sintering strength tends to be low. In the present invention, the selection of α-alumina should be carefully performed to greatly affect the properties of the alumina cement or the alumina cement composition, and is appropriately determined according to the required quality when blended into the amorphous refractory. However, the above-mentioned α-alumina is preferred from the viewpoints of fluidity, curability, strength development, spalling resistance and shrinkage. α-
Alumina has a problem with the amount of Na ₂ O as an impurity in addition to the purity of Al ₂ O ₃ .If the amount of Na ₂ O is too large, when alumina cement is used, the fluidity and fire resistance decrease, shrinkage at high temperatures occurs Therefore, it is preferable that the amount of Na ₂ O is small, and 0.5% by weight
Or less, more preferably 0.3% by weight or less of low soda type.

In the present invention, the hydraulic substance and α-aluminum
Mixing and production of alumina cement containing
Although the pulverization method is not particularly limited, α-aluminum
Na alone to a particle size equivalent to alumina cement, preferably
Is mixed with hydraulic substance after grinding to Dp50 of 2 ~ 10μ
Alternatively, a method of mixing and grinding with clinker is possible. Departure
In Ming, it is better to mix and mill with clinker
Or uniformly mixed in the alumina cement composition
Therefore, when used for irregular shaped refractories, the hardened
And the effect of improving corrosion resistance is obtained, which is preferable. K
A total of 100 of a linker or a hydraulic substance and α-alumina
The amount of α-alumina in parts by weight is preferably 2 to 80 parts by weight.
Preferably, for clinker or hydraulic substance 60-95 parts by weight
Thus, α-alumina is more preferably 5 to 40 parts by weight. α-A
As the amount of Lumina used increases, fire resistance and sintering strength at high temperatures increase.
Degree, but the curing strength and the strength after drying decrease,
Mobility also tends to decrease. Particularly preferably used
There is a trade-off with the component composition of the clinker or hydraulic substance.
However, the component ratio at the stage of using α-alumina is CaO
1 to 30% by weight, Al_TwoO_Three70-99% by weight
It is important to mix. In particular, in the present invention,
CaO 2-20% by weight, Al_TwoO _Three80-98% by weight
Preferably, CaO 3 to 20% by weight, Al_TwoO _Three80 ~
97% by weight is more preferred. If CaO content is large, it will become irregular refractory
Corrosion resistance when used is reduced and Al_TwoO_ThreeIf there is a lot of liquidity
There is a tendency that strength developability decreases. In addition, alumina
Refractory using cement or alumina cement composition
Depending on the required properties of the product,
It is not necessary, and it is possible to change the mixing ratio fluidly.
You.

The carboxylic acids used in the present invention are carboxylic acids or their alkali salts. Here, the carboxylic acid is an oxycarboxylic acid, and specific examples thereof include citric acid, tartaric acid, succinic acid, lactic acid, and gluconic acid. Examples of the alkali salt of a carboxylic acid include a sodium salt, a potassium salt, and a calcium salt. Among these, use of citric acid or an alkali salt thereof, particularly sodium citrate or potassium citrate is preferable, and use of potassium citrate is most preferable. The particle size of the carboxylic acids is preferably as small as possible so as to be easily dissolved in water when mixed with alumina cement.
It is preferably 0 mesh or less, more preferably 200 mesh or less. The purity of the carboxylic acids is not particularly limited, but carboxylic acids that are currently industrially purified can be used, and the purity is preferably about 80% by weight or more. Among them, citric acid or a salt thereof containing 0.05% by weight or less of a sulfate as an impurity, and a 1% by weight aqueous solution at 20 ° C.
It is more preferable to use citric acid or a salt thereof in which H is 7 to 10 because the pot life is excellent.

As the carbonate used in the present invention, any of inorganic carbonates can be used, but alkali carbonates such as sodium carbonate, potassium carbonate, calcium carbonate, sodium hydrogencarbonate and potassium hydrogencarbonate can be used. Preferably, any of its hydrated salt and anhydrous salt can be used.
Of these, the use of sodium carbonate is preferred, and JIS
Sodium carbonate specified by K 1201, JIS K 8624, and JIS K 8625 can be used. The particle size of the carbonate is preferably as small as possible so as to be easily dissolved in water when mixed with the alumina cement, preferably 100 mesh or less, more preferably 200 mesh or less. Although the purity of the carbonate is not particularly limited, it is possible to use an industrially purified carbonate at present, and the purity of the target carbonate is not limited.
It is preferable to use one having about 80% by weight or more.

The polyacrylic acids used in the present invention are:
Polyacrylic acid or a derivative thereof or an alkali salt thereof, specifically, polyacrylic acid, sodium polyacrylate, and a polyacrylate copolymer or an alkali salt thereof, and as a copolymer Is preferably a cross-linked branched type. As the alkali salt of polyacrylic acid, a sodium salt, a potassium salt, a calcium salt and the like can be used, but a sodium salt is preferable from the viewpoint of availability. In particular, when compounded as an additive in the present invention, it is preferable to use sodium polyacrylate. Among them, a polymer soluble in water having a low degree of polymerization and having a solid content of 95% by weight or more,
It is preferable to use an aqueous slurry having a weight percent concentration of a soluble polymerization type having a slurry viscosity at 25 ° C. of 10,000 cps or less at 25 ° C. from the viewpoint of improving the flowability of calcium aluminate. The viscosity of the aqueous slurry can be measured by a B-type viscometer, and indicates the degree of polymerization. As the degree of polymerization increases, the viscosity tends to increase.
A viscosity of 2,000 cps is preferred. In the present invention, the ionicity and pH of the aqueous slurry of polyacrylic acids are not particularly limited, but when blended with alumina cement,
In order to obtain greater fluidity, the polyacrylic acids are anionic and have a pH of 1% by weight of the slurry at 25 ° C.
H is preferably neutral to alkaline, and particularly, pH 7.5
To 11 is more preferred. In addition, the powder type is preferable because polyacrylic acids can be premixed in advance with the alumina cement, and the work of separately adding or mixing at the time of construction can be reduced. Powderization of polyacrylic acids can be performed by subjecting a liquid product to a drying treatment such as a spray dryer.

The polymethacrylic acids used in the present invention are classified into nonfunctional monomers such as methyl methacrylate, monofunctional monomers such as diethylaminoethyl methacrylate, and polyfunctional monomers such as ethylene dimethacrylate. Methacrylic monomer, polymethacrylic acid or an alkali salt thereof, and a methacrylic ester-based synthetic resin containing a copolymer, ionicity when dissolved in water is preferably anionic, and the pH of the slurry is neutral to alkaline. It is important that the pH is 7-12. Examples of the alkali salt of polymethacrylic acid include a sodium salt, a potassium salt, and a calcium salt, and the sodium salt is preferable from the viewpoint of the effect of using the alumina cement together. If the degree of polymerization of the polymethacrylic acid is too large, the flow value becomes small when kneading with the alumina cement, and the fluidity is undesirably reduced. 50-10
A degree of polymerization of about 0,000 is preferred. Further, polymethacrylic acids can be premixed with alumina cement in advance, and the powder type is preferable because the work of separately adding or mixing during construction can be reduced. Powdering of polymethacrylic acids can be performed by subjecting a liquid product to a drying treatment such as a spray dryer when producing polymethacrylic acids.

The acrylic acid-methacrylic acid copolymer used in the present invention is a copolymer having a molecular weight of 5,000 to 20,000, and although sodium salts and potassium salts can be used, it is easily available. The use of sodium salts is preferred. Particularly, in the present invention, it is preferable to use a sodium salt of an acrylic acid-methacrylic acid copolymer. Among them, a water-soluble polymer having a solid content of 95% by weight or more and a slurry viscosity of 40% by weight at 25 ° C. However, the use of a soluble polymerization type of 10,000 cps or less is preferred from the viewpoint of improving the fluidity of the alumina cement. The viscosity of the water-soluble slurry can be measured by a B-type viscometer, and indicates the degree of polymerization, and the higher the degree of polymerization, the higher the viscosity tends to be. It is preferable to use one having a slurry viscosity of 100 to 2,000 cps, more preferably one having a slurry viscosity of 300 to 1,000 cps. The ratio of copolymerization of acrylic acid and methacrylic acid is 9/1 by weight ratio of acrylic acid / methacrylic acid.
The ratio of 〜 to 4/6 is preferable, and the copolymer of 8/2 to 5/5 has excellent dispersing action and is more preferable. A particularly preferred copolymer combination has a weight ratio of sodium acrylate / sodium methacrylate of 8/2 to 5/5. When the ratio of acrylic acid is too large, the characteristics of acrylic acid become strong, and the fluidity tends to decrease and the coagulation time tends to be shortened.When the ratio of acrylic acid is too small, the characteristic of methacrylic acid is strongly shown, and when kneading, This is not preferred because not only the viscosity tends to be high, and the curing tends to be delayed, but also the copolymerization tends to be impossible. In the present invention, the ionicity and pH of the water-soluble slurry of acrylic acid-methacrylic acid copolymer are not particularly limited, but when blended with alumina cement, acrylic acid- It is important that the methacrylic acid copolymer is anionic and that the pH of the 1% by weight aqueous slurry at 25 ° C. is neutral to alkaline, and the pH is preferably 7.5 to 11. Also, acrylic acids
The methacrylic acid copolymer can be premixed with the alumina cement in advance, and the powder type is preferable because the time for separately adding and mixing during construction can be reduced. Powdering of the acrylic acid-methacrylic acid copolymer can be carried out by subjecting a liquid product to a drying treatment with a dryer such as a spray dryer.

The boric acid used in the present invention is boric acid or an alkali salt thereof. Here, boric acid is a substance that is also called boric acid, orthoboric acid, or orthoboric acid,
It is represented by the chemical formula H ₃ BO ₄ and contains pyroboric acid, tetraboric acid, and metaboric acid. The method for producing boric acid is not particularly limited, but it is usually obtained by adding sulfuric acid to a raw boric acid ore, heating and decomposing, separating and extracting boric acid, and then purifying. Examples of the boric acid alkali salt include a sodium salt, a potassium salt, and a calcium salt. Of these, a sodium salt or a potassium salt is preferable, and any of a hydrated compound and an anhydrous compound thereof can be used. The particle size of the boric acids is preferably as small as possible so as to be easily dissolved in water when mixed with the alumina cement. Further, the purity of boric acids is not particularly limited,
Currently, a possible industrial use of what is being purified, BO ₄ minutes in boric acids are preferably the use of 80 wt% or more.

According to the present invention, there is provided an alumina cement comprising one or more members selected from the group consisting of carboxylic acids, carbonates, polyacrylic acids, polymethacrylic acids, acrylic acid-methacrylic acid copolymers, and boric acids. An additive is used in combination. The combination of types of additives
Depending on the alumina cement, carboxylic acids-carbonates-polyacrylic acids, carboxylic acids-carbonates-boric acids, and carboxylic acids-carbonates-polyacrylic acids-boric acids can be appropriately selected and not particularly limited. Is preferred from the viewpoint that a balance between fluidity, curability, and strength development can be ensured. In particular, a mixture of sodium citrate as a carboxylic acid, sodium carbonate as a carbonate, sodium polyacrylate as a polyacrylic acid, and borax as a boric acid is more preferable because of its excellent fluidity as an alumina cement composition. These additives are preferably blended so that the total amount of the additives is not more than 5.0 parts by weight with respect to 100 parts by weight of the alumina cement, and 0.1 to 2.0 parts by weight has little curing delay and ensures high fluidity. It is more preferable from the viewpoint that can be made. When carboxylic acid-carbonate-polyacrylic acid is used, the mixing ratio of the additive is 100% of polyacrylic acid.
Carboxylic acids 20 to 40 parts by weight, carbonate 60
To 100 parts by weight, and when carboxylic acids-carbonates-boric acids are used, based on 100 parts by weight of carboxylic acids, 20 to 50 parts by weight of carbonate, 5 to 25 parts by weight of boric acid, When carboxylic acids-carbonates-polyacrylic acids-boric acids are used, 10 to 30 parts by weight of carboxylic acids, 50 to 80 parts by weight of carbonates, and 25 to 45 parts by weight of boric acids are used for 100 parts by weight of polyacrylic acids. Parts are preferred.

In the present invention, the method of compounding the additives is not particularly limited, and each additive is compounded so as to have a predetermined ratio, and the clinker and V-blender, corn blender, Nauta mixer, and pulverized in advance are used. Mix uniformly using a mixer such as a pan mixer and an omni mixer, or mix and crush with a crusher such as a vibration mill, a tube mill, a ball mill, and a roller mill after blending with a clinker at a predetermined ratio. Is possible. Furthermore, in the present invention, the individual additives or the mixture of the additives are added at a temperature of 100 to 300 ° C. for 30 minutes or more, preferably 60 minutes or more.
Heat treatment of drying or light baking for more than one minute is preferable because the fluidity when blended with the alumina cement is improved, and the effect of heat treatment at 150 to 200 ° C. is particularly remarkable. Additives of the present ^{invention, GC-MS, C 13 -NMR} , HPL
It can be analyzed by instrumental analysis such as C, ion chromatography, and FT-IR, activation analysis, and the like.

The refractory aggregate used in the present invention may be a refractory aggregate generally used for irregular-shaped refractories, and specifically includes 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 powder such as easily sintered alumina, fused silica, calcined mullite, chromium oxide, bauxite, andalusite, sillimanite, chamotte, quartzite, olivine, clay, zircon, zirconia, dolomite, perlite, vermiculite, brick Waste, pottery waste, silicon nitride, boron nitride, silicon carbide, and nitride It is possible to use such Mototetsu. Especially,
In the amorphous refractory of the present invention, in terms of corrosion resistance, durability, and fire resistance, magnesia, magnesia spinel,
It is preferable to use one or more refractory aggregates selected from alumina and ultrafine powder. Further, from the viewpoint of suppressing the penetration of slag into the amorphous refractory, a combination of magnesia and alumina or a combination of magnesia spinel and alumina is preferable.

Here, magnesia means Mg (OH) ₂ , magnesia carbonate, natural MgO extracted from seawater by the seawater method.
Magnesite, or a sintered magnesia clinker obtained by firing natural magnesia carbonate in a rotary kiln or the like, or an electrofused magnesia clinker obtained by melting the sintered magnesia clinker in an electric furnace or the like to a predetermined size. Crushed and sieved, Mg
O 2 having a purity of 80% by weight or more is preferable in terms of excellent corrosion resistance when used for an amorphous refractory, and those having few impurities such as SiO ₂ and TiO ₂ are preferable, and the purity of MgO is 95% by weight.
Not less than, CaO content of from 2 wt% or less, the content of SiO ₂ is 0.5 wt% or less, magnesia content below 0.5% by weight of B ₂ O ₃ is more preferable from the viewpoint of excellent corrosion resistance. In addition, magnesia with spinel coating, magnesia with magnesium titanate in the grain boundaries, magnesia with calcium aluminate generated on the surface of magnesia particles, and special magnesia clinker used for basic bricks and heat-resistant spalling Special magnesia, such as magnesia and zirconia clinker, with improved properties can also be used.

The magnesia spinel used in the present invention refers to magnesium hydroxide, calcined magnesia, or the like.
O Raw material and Al such as aluminum hydroxide and calcined alumina
₂ O ₃ raw materials are blended so as to have a predetermined ratio, and are reacted and sintered at a temperature of about 1,800 to 1,900 ° C using a baking device such as a rotary kiln to produce spinel clinker. Examples thereof include those obtained by crushing and sieving a molten magnesia spinel having a predetermined size in an apparatus, and a mixture of the baked and molten materials. MgO / Al ₂ O ₃ in magnesia spinel
Is preferably from 1/1 to 0.1 / 1, more preferably from 0.4 / 1 to 0.1 / 1.
When 0.2 / 1 is blended with the amorphous refractory, it is more preferable from the viewpoint of excellent durability.

The alumina used in the present invention is a hydroxide
Al such as luminium and calcined alumina _TwoO_ThreeRaw materials, rotor
Sintering using a kiln or other melting equipment such as an electric furnace.
And / or melted, crushed to size and sieved
And the mineral composition is α-alumina or β-alumina.
Aluminum oxide, such as alumina
Alumina, calcined alumina, easily sintered alumina, etc.
Usually, Al_TwoO_Three90% by weight or more
Most preferably, α-alumina is used. Also, alumina
Heat resistant stainless steel obtained by melting zirconia and zirconia
Alumina and zirconia clinker with improved durability
Can also be used.

The refractory aggregate is usually 5 to 3 mm, 3 to 1 mm,
Particles having a particle size of 1 to 0 mm, under 200 mesh, under 325 mesh, etc. are 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. The ultrafine powder used in the present invention is a refractory fine powder in which particles having a particle size of 10 μ or less account for 80% by weight or more, have an average particle size of 1 μ or less, and have a specific surface area of 10 m ² by the BET method.
/ g or more is preferable because when blended into an amorphous refractory, fluidity can be ensured and high strength is obtained. In particular,
Silica fume, colloidal silica, easily sintered alumina, amorphous silica, zircon, silicon carbide, silicon nitride, chromium oxide, and inorganic fine powder such as titanium oxide can be used, among which silica fume, colloidal silica, And easily sintered alumina fine powder are preferred.

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, a total of 100 parts by weight of the alumina cement or the alumina cement composition and the refractory aggregate is used. Medium, fire-resistant aggregate 9
It is preferably 9.5 to 50 parts by weight, and more preferably 98 to 85 parts by weight from the viewpoint of corrosion resistance and strength. The particle size adjustment of the refractory aggregate is appropriately determined depending on the required physical properties of the amorphous refractory, and is not particularly limited. For example, alumina cement or alumina cement composition may be used.
Particle size 1 in 100 parts by weight of amorphous refractories containing up to 15 parts by weight
5 to 20 parts by weight of sintered magnesia having a diameter of 1 mm or less
5 to 10 mm of fused alumina and / or sintered alumina, or 5 to 1 mm of magnesia spinel
Those composed of 20 parts by weight and the remainder made of fused alumina and / or sintered alumina having a particle size of 1 to 10 mm are preferable in terms of good fluidity, high strength, and low slag erosion.

In the present invention, the use of an additive in addition to an irregular refractory obtained by mixing alumina cement and a refractory aggregate can be achieved by adding 1 mm, which is a constituent material of the irregular refractory.
It is preferable from the viewpoint of dispersing the following fine powder into the matrix and also from the viewpoint of dispersing and peptizing ultrafine powder. Phosphoric acid may be further added as an additive to the amorphous refractory obtained by mixing alumina cement, an additive and a refractory aggregate from the viewpoint of fluidity control.

Examples of the phosphoric acids include hexametaphosphoric acid, tripolyphosphoric acid, ultraphosphoric acid, pyrophosphoric acid, and orthophosphoric acid and salts thereof. Hexametaphosphoric acid and tripolyphosphoric acid are preferable because of their excellent dispersing action, and the pH of a saturated aqueous solution is preferably Alkaline, pH 8.0-1
1.0 is more preferred. The salts of phosphoric acids are sodium, potassium, and calcium salts,
Sodium salts are preferred because they are readily available. Phosphoric acid having a particle size of about 200 mesh or less is preferable because it is easily dissolved at the time of kneading and has excellent dispersing action, and in terms of quality, those generally marketed as pharmaceuticals and food additives can be used. is there.

In the present invention, these additives can be used alone or in combination of two or more. Particularly, carboxylic acids and boric acid, phosphoric acids and boric acid, boric acid and polyacrylic acids, and boric acid are used. And a copolymer of acrylic acid and methacrylic acid are preferred from the viewpoint of excellent dispersing action.

The method for producing the amorphous refractory of the present invention is not particularly limited, and each material is blended at a predetermined ratio according to the usual method for producing an amorphous refractory, and the V-shaped blender is used. It is also possible to perform uniform mixing using a mixer such as a corn blender, a Nauta mixer, a bread mixer, and an omni mixer, or to perform kneading at a predetermined ratio and directly weigh the kneader. .

Further, the amorphous refractory of the present invention may be added to a foamed material such as metal aluminum or metal magnesium which reacts with an aqueous alkali solution to generate hydrogen gas, or an organic fiber such as vinylon fiber, polypropylene fiber or vinyl chloride fiber. If necessary, a basic colloid such as aluminum lactate, a nitrogen gas generating decomposition fiber, and an explosion-preventing material such as humic acids may be blended for the purpose of preventing explosion during drying of the cured product. Further, conventionally used for the purpose of improving properties such as fluidity of the cement, pot life, hardening time, and strength development, melamines,
Surfactants such as naphthalene sulfonic acids, polycarboxylic acids, and condensates of formaldehyde (admixture material for new concrete; CMC Corporation, issued July 31, 1989), AE
A water reducing agent (cement / concrete; No. 556 P36-45 June issue 1993) and saccharides such as dextrin and starch can be blended as required.

[0038]

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

Example 1 A raw material of CaO and a raw material of Al ₂ O ₃ were blended so as to have a clinker mineral composition ratio shown in Table 1 and mixed and pulverized by a ball mill.
After firing in a rotary kiln at a temperature of 1,000 to 1,600 ° C,
The mixture was allowed to cool to produce clinker. Table 1 also shows the chemical components of the produced clinker, CaO and Al ₂ O ₃ . This clinker is pulverized by a batch type ball mill, and has a Blaine value of about 4,
500-6,000 cm ² / g of hydraulic material was produced. The produced hydraulic material was used as alumina cement, and 25 parts by weight thereof and 75 parts by weight of refractory aggregate a were mixed to prepare an amorphous refractory. 11 parts by weight of water was added to 100 parts by weight of the prepared refractory, and the mixture was kneaded with a mortar mixer for 3 minutes in a constant temperature room at 25 ° C., molded and cured to prepare a cured product of the refractory. And its physical properties were measured. The results are also shown in Table 1.

<Materials> CaO raw material: calcined alumina, commercial product Al ₂ O ₃ raw material: limestone powder, commercial product, under 100 mesh Fire-resistant aggregate a: sintered alumina, trade name “Aluminite A37” manufactured by Inner / Outer Ceramic Company '', 2.36-1.17mm30 parts by weight, 1.17-
0.59mm20 parts by weight, 0.59 ~ 0.30mm10 parts by weight, and 0.3mm below
15 parts by weight mixed product

<Measurement method> Chemical components: CaO and Al ₂ O ₃ are measured according to JIS R 2522. Mineral composition: X-ray diffraction diagram measured by X-ray diffraction analyzer.
Qualitative analysis by Zevin method Fluidity: Using amorphous refractories after kneading for 3 minutes,
The spread diameter after tapping 15 times with the flow table is JI
Measured according to SR 2521. Curing time: 500 g of the formed refractory was transferred to a polybeaker and measured with a platinum resistance thermometer and a dot recorder. Curing strength: The formed refractory is cast into a 4x4x16cm formwork while stamping it with a piercing rod, and the surface is flattened with a cement knife to form a hardened body. Compressive strength after curing for 24 hours Drying Strength: The cured product after curing is dried at 110 ° C. for 24 hours, and is allowed to cool to room temperature. Compressive strength Firing strength: The dried product is placed in a siliconite electric furnace at a rate of 5 ° C./min up to 1,000 ° C. Compressive strength after holding for 2 hours after temperature rise and cooling to room temperature Shrinkage: Residual linear change rate of cured body after firing based on 24 hours curing

[0042]

[Table 1]

As is clear from Table 1, the alumina cement of the present invention can secure an appropriate pot life of about 1 hour or more, and has high curing strength, dry strength and firing strength as compared with the comparative examples. Is obtained, and the shrinkage is also within an allowable range of about -0.0.
Within 25. Therefore, when the alumina cement of the present invention is used, the unit cement amount in the amorphous refractory can be reduced, and properties such as wear resistance and corrosion resistance are improved.

Example 2 The procedure of Example 1 was repeated except that the clinker-13 prepared in Example 1 and α-alumina were blended in the proportions shown in Table 2 and pulverized and mixed with a ball mill to obtain alumina cement. Was. The results are also shown in Table 2. Table 2 also shows CaO and Al ₂ O ₃ in the alumina cement.

<Material used> α-alumina: trade name “A13 alumina” manufactured by Nippon Light Metal Co., Ltd.

[0046]

[Table 2]

As is clear from Table 2, the alumina cement of the present invention can secure a more appropriate pot life than conventional products, and can obtain high curing, drying, and firing strengths. Was also acceptable. In addition, despite the low CaO content, it has high strength development, and when the alumina cement of the present invention is used, the amount of unit cement in the amorphous refractory is reduced, and properties such as wear resistance and corrosion resistance are reduced. improves.

Example 3 The same procedure as in Example 1 was carried out except that clinker and α-alumina were blended in the proportions shown in Table 3. The results are also shown in Table 3.

[0049]

[Table 3]

As is clear from Table 3, the alumina cement of the present invention has good fluidity and hardening time, and has high curing strength, dry strength and firing strength.
One having a small shrinkage was obtained.

Example 4 20 parts by weight of alumina cement comprising 60 parts by weight of clinker and 40 parts by weight of α-alumina, and 100 parts by weight of alumina cement
1 part by weight of the various additives shown in Table 4 was blended with respect to parts by weight to obtain an alumina cement composition, 20 parts by weight of the alumina cement composition, 80 parts by weight of refractory aggregate b, and the alumina cement composition and the refractory bone. 8.3 parts by weight of water was added to 100 parts by weight of an amorphous refractory made of a material, and kneading and curing were performed in a constant temperature room at 20 ° C. Was prepared and its characteristics were evaluated. The results are also shown in Table 4. A similar test was performed using a commercially available alumina cement for comparison. The results are also shown in Table 4.

<Material used> Refractory aggregate b: sintered alumina, trade name "SR" manufactured by Showa Denko KK
W '', 3.36 to 1.19 mm 28 parts by weight, 1.19 to 0.59 mm 17 parts by weight,
0.59 to 0.297mm 15 parts by weight, 0.297mm below 14 parts by weight, and 32
5 6 parts by weight under mesh Additive A: Sodium citrate, Reagent 1 manufactured by Ishizu Pharmaceutical Co.
Grade additive B: sodium carbonate, first grade reagent manufactured by Ishizu Pharmaceutical Co., Ltd. additive C: sodium polyacrylate, commercially available additive D: polysodium methacrylate, commercially available additive E: sodium acrylate / sodium methacrylate 7/3 copolymer Additive F: Borax, 1st grade reagent manufactured by Ishizu Pharmaceutical Commercially available α: Alumina cement, trade name “S-2” manufactured by Denki Kagaku Kogyo Co., Ltd. Commercially available β: Alumina cement, manufactured by Alcoa Product name “CA25R” Commercial product γ: Alumina cement, product name “Sekar 80” manufactured by Lafarge

[0053]

[Table 4]

As is clear from Table 4, the alumina cement composition of the present invention has an appropriate pot life and high fluidity as compared with commercial products, and has extremely high curing strength, dry strength,
And firing strength. The shrinkage was also small.

Example 5 An experiment was carried out in the same manner as in Example 4 except that additives were added as shown in Table 5 to 100 parts by weight of alumina cement. The results are also shown in Table 5.

[0056]

[Table 5]

As is evident from Table 5, the alumina cement composition of the present invention has excellent fluidity without significant hardening delay, has high curing strength, dry strength, and firing strength, and has a low shrinkage. Was also small.

Example 6 The same procedure as in Example 4 was carried out except that additives were added as shown in Table 6 to 100 parts by weight of alumina cement. The results are also shown in Table 6.

<Materials used> Additive G: potassium citrate, first grade reagent manufactured by Ishizu Pharmaceutical Additive H: potassium gluconate, first grade reagent manufactured by Ishizu Pharmaceutical Additive I: sodium tartrate, manufactured by Ishizu Pharmaceutical Reagent 1st grade Additive J: Citric acid, 1st grade reagent manufactured by Ishizu Pharmaceutical Additive K: Potassium carbonate, 1st grade reagent manufactured by Ishizu Pharmaceutical Additive L: Polyacrylic acid, commercially available Additive M: Polymethacryl Acid, commercial product Additive N: copolymer of acrylic acid / methacrylic acid 5/5 Additive O: copolymer of sodium acrylate / sodium methacrylate 8/2 Additive P: sodium acrylate / sodium methacrylate 5 / 5 Copolymer Additive Q: Copolymer of sodium acrylate / sodium methacrylate 4/6

[0060]

[Table 6]

As is evident from Table 6, the alumina cement composition of the present invention has excellent fluidity without significant hardening delay, has high curing strength, dry strength and firing strength, and has a shrinkage rate. Is small.

Example 7 The same procedure as in Example 4 was carried out except that additives were added as shown in Table 7 to 100 parts by weight of alumina cement. The results are also shown in Table 7.

[0063]

[Table 7]

As is clear from Table 7, the alumina cement composition of the present invention has excellent fluidity without significant hardening delay, and has high curing strength, dry strength, and calcination strength. Was small.

Example 8 The same procedure as in Example 4 was carried out except that as shown in Table 8, 1.5 parts by weight of an additive was added to 100 parts by weight of alumina cement. The results are also shown in Table 8.

[0066]

[Table 8]

As is clear from Table 8, the alumina cement composition of the present invention has excellent fluidity without significant hardening delay, and has high curing strength, dry strength, and calcination strength. Was small.

Example 9 60 parts by weight of clinker and 40 parts by weight of α-alumina were mixed to form alumina cement, 40 parts by weight of refractory aggregate c5 to 3 mm, 45 parts by weight of refractory aggregate c3 to 1 mm, refractory bone Material d1mm
A mixture of 8 parts by weight of crude product and 7 parts by weight of refractory aggregate d200 mesh was used as a refractory aggregate, and 0.1 part by weight of additive R was added to 100 parts by weight of this alumina cement, refractory aggregate and alumina cement. 9, and mixed with an omni mixer manufactured by Chiyoda Giken Co., Ltd. for 20 minutes to produce an irregular-shaped refractory material. The results are also shown in Table 9.

<Materials> Refractory aggregate c: fused alumina, manufactured by Showa Denko Corporation Refractory aggregate d: sintered magnesia, manufactured by Ube Chemical Co., Ltd. Additive R: polyacrylic acid, commercially available

<Measurement method> Erosion test: Basicity CaO / SiO ₂ = 1.5 in accordance with JIS R 2214
An erosion test was carried out using synthetic slag of No. 1, and the erosion depth of the slag was measured by EPMA.

[0071]

[Table 9]

As is clear from Table 9, the amorphous refractory of the present invention has a low content of the alumina cement composition,
In addition, despite its low CaO content in amorphous refractories, it has excellent fluidity and hardening time, has high curing strength, dry strength, and firing strength, and has low slag erosion. there were.

Example 10 Particles having a particle size composition shown in Table 10 having a particle size of 5 to 3 mm () 40 parts by weight, 3 to 1 mm () 45 parts by weight, 1 mm below () 10 parts by weight, and 200 mesh below () 5 parts by weight Example 9 was carried out in the same manner as in Example 9 except that the additive R was mixed as shown in Table 10 with respect to 100 parts by weight of the alumina cement, the refractory aggregate, and the alumina cement. Table 1 shows the results
0 is also added.

<Materials Used> Refractory aggregate e: sintered alumina, manufactured by Showa Denko Corporation Refractory aggregate f: sintered magnesia spinel, manufactured by Shin Nippon Chemical Co., Ltd.

[0075]

[Table 10]

As is evident from Table 10, the amorphous refractory of the present invention is excellent in spite of a small amount of the alumina cement composition and a small content of CaO in the amorphous refractory. It had fluidity and hardening time, had high curing strength, dry strength, and firing strength, and had little slag erosion.

Example 11 The same procedure as in Example 9 was carried out except that the ultrafine powder having the amount shown in Table 11 and 0.1 part by weight of various additives with respect to 100 parts by weight of alumina cement were blended. The results are shown in Table 11.

<Materials Used> Ultrafine powder α: silica fume, manufactured by Elchem Co., Ltd. Ultrafine powder β: finely divided alumina, manufactured by Alcoa “A16S”
G "Additive S: A mixture of boric acid / sodium citrate weight ratio 1/2 Additive T: Boric acid / sodium tripolyphosphate weight ratio 1
/ 2 mixture Additive U: boric acid / sodium polyacrylate weight ratio 1
Additive V: a mixture of boric acid / sodium polymethacrylate at a weight ratio of 1/2 Additive W: a mixture of boric acid / sodium acrylate-sodium methacrylate at a weight ratio of 1/2 Additive X: sodium acrylate / Sodium methacrylate 6/4 copolymer Additive Y: Sodium tripolyphosphate, manufactured by Taihei Chemical Co. Additive Z: Boric acid

[0079]

[Table 11]

As is clear from Table 11, the amorphous refractory of the present invention is excellent in spite of the low content of the alumina cement composition and the low content of CaO in the amorphous refractory. It had fluidity and hardening time, had high curing strength, dry strength, and firing strength, and had little slag erosion.

[0081]

As is clear from the examples, the alumina cement, the alumina cement composition, and the amorphous refractory of the present invention have an appropriate pot life, high strength development, and high fluidity which are not found in conventional products. It has high corrosion resistance and abrasion resistance. When this is used in the refractory field, it is possible to reduce the amount of alumina cement to be blended in order to secure a certain strength as an amorphous refractory. Can be reduced, and as a result, the corrosion resistance is improved.

The alumina cement, the alumina cement composition and the amorphous refractory of the present invention can be used not only in the vicinity of furnaces such as blast furnaces and electric furnaces where alumina cement has been used, but also in spraying materials, press-fitting. Materials, irregular refractories such as gutter materials, mixed-iron cars, topied, tundish, ladle, and lance materials, as well as ironmaking and steelmaking facilities such as soaking furnaces, heating furnaces, and coke ovens In addition, it can be used for cement kiln related equipment, etc., and it is possible to make amorphous in fields such as basic bricks, which were difficult to form with conventional alumina cement, such as converters and special refining pots. High durability that is not found in products can be expected. In addition, not only in the refractory field, high strength development, high fluidity, high corrosion resistance,
Also, it can be used as a lining of a chemical plant or a corrosion-resistant material requiring abrasion resistance. Furthermore, the lining material using the alumina cement, the alumina cement composition, and the amorphous refractory of the present invention has high fire resistance, high strength development, abrasion resistance, and high corrosion resistance. It can be used not only as a corrosion-resistant material, abrasion-resistant material, fire-resistant material and the like for equipment and the like, but also as a hydraulic ceramic, a catalyst carrier, a corrosion-resistant building material and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C04B 35/66 C04B 35/66 K // (C04B 28/06 24:04 22:10 24:26 22:08) 111: 26 111: 28

Claims (5)

[Claims] 1. A _{CaO · Al 2 O 3, CaO} · 2Al 2 O 3, and 12Ca
And also contains the mineral composition of the O · 7Al ₂ O _3, 12 in the mineral composition
CaO 7Al ₂ O ₃ is 5 to 15% by weight, and the chemical components CaO and
Alumina cement CaO in total in of Al ₂ O ₃ is contained hydraulic substance is 20 to 40 wt%. 2. A hydraulic material comprising the hydraulic substance according to claim 1 and α-alumina, wherein α-alumina is 5 to 80 parts by weight based on a total of 100 parts by weight of the hydraulic substance and α-alumina. Alumina cement, characterized in that: 3. The alumina cement according to claim 1 or 2, and a carboxylic acid, a carbonate, a polyacrylic acid,
An alumina cement composition containing one or more additives selected from the group consisting of polymethacrylic acids, acrylic acid-methacrylic acid copolymers, and boric acids. 4. An amorphous refractory comprising the alumina cement according to claim 1 and a refractory aggregate. 5. An amorphous refractory comprising the alumina cement composition according to claim 3 and a refractory aggregate.