JPH08259301A - Alumina cement composition and monolithic refractory using the same - Google Patents

Abstract

PURPOSE: To improve fluidity in a high-temperature application, development of strength, resistance to corrosion and spalling by using a specific alumina cement, an alkali metal carbonate, a carboxylic acid, boric acids and a polyacrylic acid. CONSTITUTION: This alumina cement composition is obtained by formulating 0.5-2.5 pts.wt. of 3 or more kinds of additives selected from among an alkali metal carbonates which are heat-treated at 10-400 deg.C and have <=100 mesh particle sizes, carboxylic acids, boric acids and polyacrylic acids to 100 pts.wt. of alumina cement comprising 70-50 pts.wt. of clinker which has a mineral composition of CaO.Al2 O3 and CaO.2Al2 O3 where CaO content is 25-33wt.% and Al2 O3 content is 75-67wt.%, and 30-50 pts.wt. of α-alumina and containing <=0.5wt.% of SiO2 , <=0.5wt.% of TiO2 , <=0.5wt.% of Fe2 O3 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an alumina cement composition and an amorphous refractory material using the same, more specifically, a high fluidity and a high strength developing property at the time of high-temperature construction as compared with a conventional alumina cement composition. The present invention relates to an alumina cement composition having good corrosion resistance, spalling resistance and the like, and an amorphous refractory material using the same.

[0002]

[Prior art and its problems] Conventionally, a specific ratio of CaO / Al has been used as an alumina cement or an alumina cement composition.
₂ O ₃ , 12CaO.7Al ₂ O ₃ , and amorphous, α-Al ₂ O ₃ ,
Alumina cement composition containing a hydroxycarboxylic acid, and an inorganic carbonate (Japanese Patent Application No. 45-129562, Japanese Patent Application Laid-Open No. 49-32921, Japanese Patent Application Laid-Open No. 50-102617, and Japanese Patent Application Laid-Open No. 55-121933, etc.), an alumina cement containing a water-soluble polyacrylic acid and / or a methacrylic acid-acrylic acid copolymer and an alkali metal carbonate (Japanese Patent Application Laid-Open No. 5-312058).
5-75947 and JP-A-55-75948), and
Alumina cement compositions (Japanese Patent Laid-Open No. 6-157097) composed of calcium aluminate, polyacrylic acids, boric acids, and carbonates or carboxylic acids are known.
In addition, the influence of the mineral composition of alumina cement and the types of additives on the fluidity, hardening, and strength development of alumina cement is also known (HIGH ALUMINA CEMENT
S AND CONCRETES TD ROBSON 1962).

These alumina cements or alumina cement compositions are intended to improve the properties such as high strength development, high fire resistance, and high fluidity when applied at room temperature, and the physical properties deteriorate when applied at high temperature. Was not preferable.

The mineral composition of conventional alumina cement has been limited to those mainly containing CaO.Al ₂ O ₃ in terms of securing fluidity and imparting strength development. Curing rate adjustment of the CaO · Al ₂ O _3, is proposed which incorporated the calcium aluminate retarders such as fast hard calcium aluminate and CaO · 2Al ₂ O _3, such as 12CaO · 7Al ₂ O ₃ (JP-B-44-4220 and JP-A-54-139639). However, 12CaO ・ 7Al ₂ O ₃ has the characteristic of exhibiting rapid hardening, and even if the curing adjustment is made with additives, etc., the strength of CaO ・ Al ₂ O ₃ -based alumina cement is inferior in terms of strength development. And
In addition, when CaO.2Al ₂ O ₃ is blended, there are problems such as retardation of curing and deterioration of strength development.

Further, there is an alumina cement composition containing a water-soluble inorganic fluoride for high-temperature construction, but there is a problem that the water-soluble inorganic fluoride is not suitable for practical use as a non-medical deleterious substance. (JP-A-61-86454).

It has not been possible to obtain high fluidity during high-temperature construction, even with conventional alumina cements having high fluidity or those obtained by adding additives to alumina cement to enhance fluidity.

As described above, although many alumina cements or alumina cement compositions are described in patents and literatures, the composition of alumina cements actually industrialized is mainly composed of CaO.Al ₂ O _3. Limited, for the purpose of adjusting the hardening of alumina cement, and for the purpose of imparting high fire resistance and strength development, it contains 12CaO.7Al ₂ O ₃ , α-Al ₂ O ₃ , and various additives. As a result of reducing the CaO content in the clinker for the purpose of ensuring high fire resistance, even if some CaO.2Al ₂ O ₃ is contained in an amount of about 5% by weight or less, as in the present invention, There was no alumina cement that positively used CaO · 2Al ₂ O ₃ .

Although these alumina cements or alumina cement compositions have good fluidity, strength development, curability, and fire resistance, they are currently used in the field of refractory materials, especially in ironmaking equipment and steelmaking equipment. As an amorphous refractory required in the steel field, there is a problem that fluidity, strength development, fire resistance, corrosion resistance, etc. are insufficient.

Therefore, a combination of refractory aggregates constituting an amorphous refractory has been studied to solve the problems of these alumina cements, but it was not sufficient.

Further, in order to further improve the corrosion resistance to the metal produced in the iron ore field and the slag generated during the production, it is preferable to add a basic aggregate such as magnesia, and the hardened material is digested with kneading water. As a result, cracking occurs, or it functions as a hardening accelerator for alumina cement, and because of soluble components such as Mg ions that are eluted from the basic aggregate, the fluidity during kneading is reduced, and the pot life during construction is reduced. However, there was a problem that problems such as hardening in the mixer and hopper were likely to occur. In particular, such as slag line, ladle laying part, molten steel part, repair in high temperature construction such as in blast furnace, etc., where high strength development, corrosion resistance, and spalling resistance are required. Amorphous refractory has a problem that conventional alumina cement or alumina cement composition lacks fluidity and strength development.

In addition, although conventional alumina cement and conventional techniques have some advantages and disadvantages in terms of durability improvement, significant improvement in performance could not be expected.

As a result of various studies to solve these problems, the present inventor has found that a hydraulic clinker having a specific mineral composition and chemical components, α-Al ₂ O ₃ , and a specific additive are used. The present invention has been completed with the knowledge that the above problems can be solved by using the blended alumina cement composition.

[0013]

Means for Solving the Problems That is, the present invention is mineral composition is CaO · Al ₂ O ₃ and CaO · 2Al ₂ O _3, chemical composition CaO25~
Clinker 70-5, which is 75-67 wt% Al ₂ O ₃ at 33 wt%
A mixture of 0 parts by weight and α-Al ₂ O ₃ 30 to 50 parts by weight 100
Part by weight and at least three or more additives of carboxylic acids, alkali metal carbonates, boric acids, polyacrylic acids or polymethacrylic acids having a heat history at 100 to 400 ° C. 0.5
An amorphous refractory material containing an alumina cement composition containing about 2.5 parts by weight and a refractory aggregate.

The present invention will be described in detail below.

[0015] clinker used in the present invention are CaO · Al ₂ O ₃ and CaO · 2Al ₂ O ₃ as the mineral composition, the chemical composition, in CaO25~33 wt%, Al ₂ O ₃ 75~67 weight %, And it is important to make the mineral composition compatible with the chemical composition.

The clinker of the present invention comprises high-purity alumina obtained by purifying natural raw materials such as red bauxite by a Bayer process or the like, Al ₂ O ₃ raw materials such as bauxite, and CaO raw materials such as limestone and quicklime. It is blended so that the prescribed component ratio is obtained, and electric furnace, reverberatory furnace, vertical furnace, open hearth furnace,
It is obtained by melting and / or firing with equipment such as a shaft kiln and a rotary kiln. In the present invention, it is preferable to produce the clinker by a calcination method in which the production rate of the calcium aluminate mineral is within the range of the present invention, as compared with the melting method, which facilitates production.

Here, when CaO is C and Al ₂ O ₃ is A, a method of synthesizing the mineral composition of CA-CA _{2 at} a time, the mineral composition of CA and CA ₂ can be used to obtain the mineral composition of the present invention. There is a method in which the mineral composition of is mixed in a predetermined ratio.

In the present invention, the content ratio of the mineral composition is Cu
-Able to be analyzed by X-ray diffraction analysis using Kα ray, and as a method for quantifying mineral composition by X-ray diffraction method, intensity ratio measurement method of diffraction line, internal standard method, Zevine method, and X-ray diffraction peak separation method In the present invention, any method can be used for quantification.

The method of measuring the intensity ratio of diffraction lines is a method of indicating the diffraction intensity of each mineral with a relative value, and the internal standard method is a method of mixing an internal standard substance and a sample at a fixed ratio, By utilizing the fact that a linear relationship is obtained between the component concentration and the diffraction line intensity ratio, this is a method of preparing and analyzing a calibration curve using a standard sample of 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 a simultaneous equation of order n. The average mass absorption coefficient is a fluorescent X-ray analysis. By method or chemical analysis,
The components of the sample can be quantified and calculated. further,
The X-ray diffraction peak separation method is a method of measuring from a crystal or glass phase of a sample.

In the present invention, it is possible to quantify the mineral composition and the vitrification rate by any method, but the measurement is simple and accurate, and the Zevine method or the diffraction line intensity ratio measurement method Is preferably used. For example, the hydraulic mineral composition ratio in the clinker of the present invention by the Zevine method is CA20-
90 parts by weight, preferably in the range of CA ₂ 80 to 10 parts by weight, CA40～80 parts, the range of CA ₂ 60 to 20 parts by weight is more preferable. If the mineral composition ratio of the clinker is outside this range, the fluidity, strength development, corrosion resistance, and spalling resistance may deteriorate. Further, for example, the mineral composition ratio of the alumina cement composition of the present invention measured by the diffraction line intensity ratio is such that the CA ₂ diffraction intensity ratio CA ₂ / CA to the CA diffraction line is
It is preferably manufactured so as to be 0.1 to 10.0, and more preferably 0.5 to 5.0 in terms of the balance of fluidity, pot life, curability, and strength development when compounded into an amorphous refractory. When it is less than 0.1, high strength development, abrasion resistance, spalling resistance and the like are deteriorated, and when it exceeds 10, fluidity and curability may be deteriorated. The mineral composition ratio here is
The d ratio of CA is 4.67Å, and the d of CA ₂ is 4.45Å.

The chemical component ratio of the clinker used in the present invention is CaO 25-33% by weight and Al ₂ O ₃ 75-67% by weight.
7 to 32 wt% and Al ₂ O ₃ 73 to 68 wt% are preferable. If the chemical composition of the clinker is outside this range, fluidity, strength development,
Corrosion resistance and spalling resistance may be poor.

The alumina cement composition of the present invention contains
CA or CA of the desired mineral composition₂, Α-Al ₂O₃Besides, 2CaO ・ Al
₂O₃・ SiO₂, CaO / TiO₂, And 4CaO ・ Al₂O₃・ Fe₂O₃Impurities such as
It is also possible to use those containing. Alumina cement
The less impurities in the composition, the better₂Is 0.5
Weight% or less, TiO₂Is 0.5 wt% or less, and Fe₂O₃Is 0.5
The amount is preferably less than or equal to%, particularly SiO 2₂, TiO₂, Fe
₂O₃, Na₂OK₂Chemical components such as O and MgO are
It is preferably less than 0.1% by weight and less. These
If a large amount of pure material is used, the alumina ceramic
The volume change of the cured product using the ment composition is high at high temperature.
It is preferable because it becomes harder and corrosion resistance to slag etc. decreases.
Not good.

It is also possible to contain a small amount of unreacted CaO or Al ₂ O ₃ within the range that does not impair the characteristics of the alumina cement composition. Unreacted CaO is preferably 2% by weight or less, unreacted Al ₂ O ₃ is preferably 10% by weight or less, and CaO is 1.
More preferably, it is 0% by weight or less, and Al ₂ O ₃ is 5.0% by weight or less.
If unreacted raw material exists in the clinker, Ca
Ions elute or exist as a filler,
The fluidity deteriorates and the pot life is shortened to accelerate hardening, and the strength development of amorphous refractories using the alumina cement decreases, and volume stability at high temperatures deteriorates. There are cases.

When the clinker is produced by the firing method, Al ₂ O
_It is preferable that the _three raw materials and the CaO raw material are mixed and / or mixed and pulverized at a predetermined ratio, and fired at a high temperature of 1,000 ° C. or higher in a rotary kiln, and more preferably 1,450 ° C. or higher. Also, when manufacturing clinker by the melting method, Al
It is important that the ₂ O ₃ / CaO molar ratio is in the range of 2 to 6, and that the mineral composition obtained after melting is the CA-CA ₂ composition,
In the melting method, the composition ratio of the mineral composition of CA and CA ₂ is thermodynamically determined, so CaO is 21.5-35.4 wt% and Al ₂ O ₃ is 78.5-
It is preferable to mix the raw materials so as to be 64.6% by weight,
It is more preferable to mix the raw materials so that the component ratio of CaO is 25.0 to 33.0 wt% and Al ₂ O ₃ is 75.0 to 67.0 wt%.

It is preferable that the compounded raw materials are melted at a high temperature of 1,500 ° C. or higher, more preferably 1,700 ° C. or higher by a melting device such as an electric furnace or an open furnace, and then the clinker is cooled by contacting with high pressure air or water. .

In the present invention, a composition consisting of CA and CA ₂ is synthesized at once so that the desired mineral composition is obtained, or CA and CA ₂ are mixed at a predetermined mixing ratio, or the composition ratio is changed. It is also possible to combine clinker consisting of different CA and CA ₂ so as to obtain a desired mineral composition ratio.

In the crushing / mixing of these clinker, the clinker may be mixed and then crushed, or the crushed crushers may be crushed and mixed, and the means for obtaining a desired mineral composition ratio is particularly limited. Not a thing. As a crusher for clinker, a crusher used for finely pulverizing powder mass can be used. For example, a roller mill, a jet mill, a tube mill, a ball mill, a vibration mill or the like can be used.

The vitrification rate of the clinker in the present invention is not particularly limited, but generally, if the vitrification rate is high, the hydraulic property becomes strong, and a cured product using the clinker can obtain high strength development. . This vitrification rate can be adjusted by a method of cooling the melted and / or fired high temperature clinker. The degree of vitrification shows that the weaker the intensity of the diffraction line is, the higher the vitrification rate is in the analysis of the mineral composition by the powder X-ray diffraction method.

The particle size of the clinker affects the fluidity, curability, and strength development, and is the specific surface area by the Blaine method.
Preferably 3,000 cm ² / g or more, more preferably at least ^{4,000cm 2 / g, 4,500~8,000cm 2 /} g being most preferred. 3,000 cm ² / g
If it is less than the above range, strength developability and fluidity may be deteriorated, or appropriate curability may not be obtained. The average particle diameter of the clinker is preferably finely pulverized to 10 μm or less because of excellent fluidity and pot life at high temperature, and more preferably 1 to 7 μm. If it is less than 1 μm, the strength developability and fluidity may decrease, and if it exceeds 7 μm, the fluidity may decrease or curing may be delayed.

The average particle size referred to here is the value of the measurement result by a commonly used particle size distribution measuring instrument such as the laser diffraction method, the laser scattering method, or the sedimentation balance method. Is.

The α-Al ₂ O ₃ used in the present invention is effective in terms of imparting high fire resistance, high temperature strength development, and volume stability to an amorphous refractory material using an alumina cement composition. The properties of the alumina cement composition, such as high fluidity, high strength development, rapid hardening, and high fire resistance, vary greatly depending on the type, and the properties not present in conventional products are exhibited for the first time due to the interaction with the combined clinker. Is what
It is a refined alumina obtained by calcining aluminum hydroxide highly purified by a Bayer process or the like in a rotary kiln or the like, and is a high purity alumina containing 90% by weight or more of Al ₂ O ₃ . Generally, it is called high-purity alumina, Bayer alumina, easy-sintering alumina, or light-burning alumina.

Α-Al ₂ O ₃ preferably has an average primary particle size (Dp50) of about 40 to 100 μ before pulverization, and the degree of calcination is a BET specific surface area of 0 by a BET method. .
Those having a range of 5 to 100 m ² / g are preferable. Here, the degree of calcination represents the degree of calcination of alumina cement,
The degree is determined by the BET specific surface area of the fired product. The higher the degree of calcination, the higher the α-conversion rate and the smaller the BET specific surface area, and the lower the degree of calcination, the lower the α-conversion rate.
ET specific surface area becomes large. Usually, this primary particle size is
When the precipitation rate of aluminum hydroxide in the Bayer process is slowed down, the diameter becomes large, and conversely, when it becomes fast, the diameter becomes small.

In the present invention, the primary particle size of α-Al ₂ O ₃ is 30 to
At 60μ, the firing degree of alumina is 2 to 10 in terms of BET specific surface area.
is preferably m ² / g, in 40~50μ, 6~8m ² / g is more preferable. The degree of calcination of α-Al ₂ O ₃ is lighter as the specific surface area is larger, and the alumina cement composition using the same has excellent sinterability at high temperature but causes large shrinkage. Further, when the specific surface area is large, the fluidity of the alumina cement composition is lowered, and conversely, when it is small, the fluidity is improved. Further, if the specific surface area is large, the sinterability of the amorphous refractory material at high temperatures is improved, but oversintering may reduce spalling resistance and increase shrinkage, and if the specific surface area is small, The opposite is true. For this reason, the selection of alumina to be blended in the present invention greatly affects the properties of the alumina cement composition, and therefore should be carefully performed, and should be appropriately determined depending on the required quality when blended in an amorphous refractory. Although it is a kimono, fluidity, curability, strength development, shrinkage,
And from the aspect of spalling resistance, the primary particle size is 30-60μ
It is preferable to use alumina whose degree of calcination is 2-10 m ² / g in terms of BET specific surface area.

Further, the higher the purity of α-Al ₂ O ₃ , the more preferable it is, and it is possible to secure the purity of 98% by weight or more of Al ₂ O _{3 in the} case of alumina produced by a usual Bayer process. . In the present invention, the amount of Na ₂ O as an impurity in addition to Al ₂ O ₃ purity is a problem, and when the amount of Na ₂ O is large, the fluidity and fire resistance of the alumina cement composition are reduced, or the material shrinks at high temperatures. Therefore, it is preferable that the amount of Na ₂ O is small, for example, 0.5% by weight or less, and 0.35% by weight or less of low sodium α-Al ₂ O ₃ is more preferable.

In the present invention, this α-Al ₂ O ₃ and clinker are blended and mixed and pulverized by a pulverizer, or α-Al ₂ O ₃ is pulverized to a particle size corresponding to alumina cement alone and then clinker pulverized. It is also possible to mix with the thing. When pulverizing α-Al ₂ O ₃ alone, it is preferable to pulverize to Dp 501 to about 10 μm. In the present invention, it is better to mix and grind α-Al ₂ O ₃ with a clinker, and it is more compatible with cement particles, and can be uniformly mixed in an alumina cement composition, and curing of an amorphous refractory using it The body tissue becomes uniform and the corrosion resistance is improved.

The blending ratio of α-Al ₂ O ₃ is as follows: clinker and α-A
30 to 5 per 100 parts by weight of alumina cement consisting of l ₂ O ₃
It is 0 part by weight, preferably 35 to 45 parts by weight. When the proportion of α-Al ₂ O ₃ is increased, the fire resistance and the sinter strength at high temperature are increased, but the curing strength and the dry strength are decreased, and the fluidity may be decreased. Particularly preferably, there is a balance with the component composition of the clinker to be blended, but the component ratio at the stage of blending α-Al ₂ O ₃ is CaO 10 to 25% by weight, Al ₂ O ₃ 90 to 75% by weight. It is preferable to mix so that CaO 15 to 20% by weight and Al ₂ O ₃ 85 to 80% by weight are preferable because they have good fluidity and high strength. In particular, in the case of amorphous refractory containing magnesia aggregate, if there is a large amount of α-Al ₂ O ₃ in the alumina cement composition, α-Al ₂ O ₃ and magnesia react at high temperature to form magnesia spinel. in the process, to show a case where the volume expansion of the alumina cement α-Al ₂ O ₃ is a large amount as exceeding 90 wt% α-Al ₂ O ₃
It is not preferable to mix the composition depending on the type and amount of the target aggregate compounded aggregate. The composition range is not limited to this range depending on the intended characteristics of the amorphous refractory using the alumina cement composition, and the mixing ratio can be fluidly changed.

In the present invention, at least three kinds of alkali metal carbonates, carboxylic acids, boric acids and polyacrylic acids are used as additives.

As the alkali metal carbonates used in the present invention, it is preferable to use alkali metal carbonates such as sodium carbonate, potassium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate, and any of its hydrated salt or anhydrous salt. Is also possible. Of these, sodium carbonate is preferably used, and sodium carbonate defined by JIS K 1201 and JIS K 8625 can be used. The particle size of the alkali metal carbonates is preferably as fine as possible so that it can be easily dissolved in water when mixed with alumina cement, and more preferably 100 mesh or less, particularly 200 mesh or less.
The purity of the alkali metal carbonate is not particularly limited, and it is possible to use an industrially refined alkali metal carbonate, and it is preferable to use one having a purity of about 80% by weight or more.

The carboxylic acids used in the present invention are oxycarboxylic acids or alkali salts thereof. Examples of the oxycarboxylic acid include citric acid, gluconic acid, tartaric acid, succinic acid, lactic acid, malic acid, salicylic acid, and the like, and examples of the alkali salt thereof include sodium salt, potassium salt, and calcium salt. Among these, it is preferable to use citric acid or an alkali salt thereof, especially sodium citrate or potassium citrate. The particle size of the carboxylic acid is preferably as fine as possible so that it can be easily dissolved in water when mixed with alumina cement, and is preferably 100 mesh or less, particularly preferably 200 mesh or less. The purity of the carboxylic acids is not particularly limited, but currently industrially purified carboxylic acids can be used, and preferably about 80% by weight or more. Among them, citric acid or its salts containing less than 0.05% by weight of sulfate as impurities, or 1% by weight at 20 ° C.
It is preferable to use citric acid or a salt thereof in which the pH of the aqueous solution having a concentration is in the range of 7 to 10 because the pot life is excellent.

The boric acid used in the present invention is boric acid or its alkali salt. Here, boric acid is also called boric acid, orthoboric acid, or orthoboric acid, and is represented by H ₃ BO ₄ , and contains pyroboric acid, tetraboric acid, and metaboric acid. The method for producing boric acid is not particularly limited, and it is usually obtained by adding sulfuric acid to a raw ore of boric acid for thermal decomposition, liberating boric acid, separating and extracting and purifying. Examples of the alkali salt of boric acid include sodium salt, potassium salt, calcium salt, and the like. Among them, the sodium salt or potassium salt is preferably used, and any of the hydrated compound and the anhydrous compound thereof can be used. The particle size of boric acid is preferably as small as possible so that it can be easily dissolved in water when mixed with alumina cement. In addition, the purity of boric acids is not particularly limited, but it is possible to use boric acid that is currently industrially refined, and bo ₄ content in boric acid is 80% by weight or more. Use is preferred.

The polyacrylic acids used in the present invention are polyacrylic acid, polymethacrylic acid or salts thereof, such as sodium polyacrylate, potassium polyacrylate, ammonium polyacrylate, etc., or sodium polymethacrylate, polymethacrylate. Examples thereof include potassium methacrylate, polyammonium methacrylate, and the like, and of these, the use of sodium polyacrylate or sodium polymethacrylate is most preferable from the viewpoint of performance, price, availability, and ease of handling. .

The amounts of the additives used are clinker and α-Al ₂ O ₃
To 100 parts by weight of alumina cement, which is a mixture of
0.5 to 2.5 parts by weight is preferable, and 1.0 to 2.0 parts by weight is more preferable. If it is less than 0.5 part by weight, workability may be lowered, and if it exceeds 2.5 parts by weight, curing may be delayed or strength may be lowered. In particular, when alkali metal carbonates, carboxylic acids, and boric acids are used as additives, carboxylic acids 2 parts are added to 100 parts by weight of alkali metal carbonates.
A mixing ratio of 40 to 290 parts by weight and boric acids 10 to 60 parts by weight is preferable, and when using alkali metal carbonates, carboxylic acids, and polyacrylic acids as additives, relative to 100 parts by weight of alkali metal carbonates, Carboxylic acids 10-50
The mixing ratio of 100 parts by weight to 100 parts by weight of polyacrylic acid is preferable, and when using alkali metal carbonates, boric acids, and polyacrylic acids as additives, 100 parts by weight of alkali metal carbonates are added to boric acids. A mixing ratio of 10 to 60 parts by weight and polyacrylic acids 100 to 150 parts by weight is preferable, and when carboxylic acids, boric acids, and polyacrylic acids are used as an additive, boric acid is 10 parts by weight with respect to 100 parts by weight of carboxylic acids. ~ 60 parts by weight and polyacrylic acid 100
A blending ratio of up to 150 parts by weight is preferable, and when using alkali metal carbonates, carboxylic acids, boric acids, and polyacrylic acids as additives, alkali metal carbonates 10
A mixing ratio of 5 to 55 parts by weight of carboxylic acids, 25 to 75 parts by weight of boric acids, and 125 to 175 parts by weight of polyacrylic acids is preferable with respect to 0 parts by weight.

The method of blending the additives in the present invention is not particularly limited, and each additive is blended in a predetermined ratio and crushed in advance with α-Al ₂
O ₃ and H-mixer such as V-type blender cone blender, Nauta mixer, pan-type mixer, and omni mixer are mixed uniformly, or after blending with clinker and α-Al ₂ O ₃ at a predetermined ratio, It is possible to mix and grind with a grinder such as a vibration mill, a tube mill, a ball mill, and a roller mill.

[0044] In the present invention, together or a material obtained by heating the additive at a temperature of 100 to 400 ° C. is mixed with a mixture of clinker and α-Al ₂ O _3, clinker, α-Al ₂ O _3, and the additive Heat and use the mixture. Additive heating temperature is 100
It is ~ 400 ° C, preferably 150 ~ 350 ° C. If it is out of this range, the fluidity may be deteriorated, an appropriate curing time may not be obtained, and the strength development may be deteriorated.

As a heating method, a method of heating at the same time as crushing, hot air heating during transportation, heating of a transportation machine, heating during storage and the like are possible.

The alumina cement composition of the present invention has an IC
P, ICPA, GC-MS, C13-NMR, HPLC,
And instrumental analysis such as FT-IR, chelate analysis, and
It is possible to specify the type and quantity ratio by activation analysis and the like.

The refractory aggregate used in the present invention may be a refractory aggregate which is usually used for an irregular shaped refractory, and specifically, molten magnesia, sintered magnesia, natural magnesia, And magnesia such as light-burned magnesia, magnesia spinel such as molten magnesia spinel and sintered magnesia spinel, fused alumina, sintered alumina, light-burned alumina, and alumina such as easily sintered alumina, silica fume, colloidal silica, light-burned alumina , And ultrafine powder such as easily sintered alumina, fused silica, calcined mullite, chromium oxide, bauxite, andalusite, sillimanite, chamotte, silica stone, loamy stone, clay, zircon, zirconia, dolomite, perlite, vermiculite, brick Kudzu, pottery kudzu, silicon nitride, boron nitride, silicon carbide, and It is possible to use silicon oxide, iron, etc., among which, from the viewpoint of corrosion resistance, durability, and fire resistance, one or more refractory materials selected from magnesia, magnesia spinel, alumina, and ultrafine powder. It is preferred to use aggregate.

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, Mg (OH) ₂ , extracted from seawater by the seawater method, magnesia carbonate, magnesite that is natural MgO, or sintered magnesia clinker obtained by firing natural carbonate magsia in a rotary kiln, and the like, and / Or electrospun magnesia clinker obtained by melting the sintered magnesia clinker in an electric furnace or the like, crushed to a predetermined size, sieved, MgO purity of 80 wt% or more, It is preferable in terms of excellent corrosion resistance, and it is preferable that impurities such as SiO ₂ and TiO ₂ are small, the purity of MgO is 95% by weight or more, the content of CaO is 2% by weight or less, and the content of SiO ₂ is
Magnesia having a content of 0.5% by weight or less and a B ₂ O ₃ content of 0.5% by weight or less is preferable from the viewpoint of excellent corrosion resistance.

In addition, it is used for spinel-coated magnesia, magnesia containing magnesium titanate at grain boundaries, magnesia for producing calcium aluminate on the surface of magnesia particles, and basic bricks.
As described in JP-A-4-357110, high purity, high bulk density, and special magnesia clinker of coarse crystal grains, and special magnesia such as magnesia zirconia clinker with improved heat spalling resistance are also available. It can be used.

The magnesia spinel is a rotary kiln prepared by mixing MgO sources such as magnesium hydroxide and calcined magnesia with Al ₂ O ₃ sources such as aluminum hydroxide and calcined alumina in a predetermined ratio. Using a firing device such as, a spinel clinker by reacting and sintering at a temperature of about 1,800 to 1,900 ℃, molten magnesia spinel melted in a melting device such as an electric furnace, crushed to a predetermined size, It is a sieved product, a mixture of these baked products and melted products, and the like. The weight ratio of MgO / Al ₂ O ₃ in the magnesia clinker is preferably 0.1 to 1, and more preferably 0.2 to 0.4 from the viewpoint of excellent durability when blended with an amorphous refractory.

Further, alumina is obtained by sintering and / or melting an Al ₂ O ₃ source such as aluminum hydroxide or calcined alumina with a firing device such as a rotary kiln or a melting device such as an electric furnace. It was crushed to a predetermined size and sieved, and the mineral composition was α-Al ₂ O ₃ or β.
-Al ₂ O _{3 and the} like, which is referred to as sintered alumina, calcined alumina, and easily sintered alumina, and is usually α-containing 90% by weight or more of Al ₂ O _3. Most preferred is the use of Al ₂ O ₃ . Further, it is also possible to use alumina-zirconia clinker or the like which is obtained by melting alumina and zirconia clinker and has improved heat resistant spalling resistance.

The particle size of the refractory aggregate is usually 5 to 3 mm, 3 to
Those having sizes of 1 mm, 1 to 0 mm, under 200 mesh, under 325 mesh, etc. are blended according to the required physical properties. Grain size adjustment of the refractory aggregate is not particularly limited because it is determined by the target physical properties of the amorphous refractory, 100 parts by weight of the irregular refractory, the alumina cement composition 2-1
5 parts by weight, 5 to 20 parts by weight of sintered magnesia having a particle size of 1 mm or less, and the balance of 2 to 15 parts by weight of fused alumina and / or sintered alumina having a particle size of 1 to 10 mm, and an alumina cement composition. 5 to 20 parts by weight of magnesia spinel with a particle size of 1 mm or less and the balance of fused alumina and / or sintered alumina with a particle size of 1 to 10 mm have good fluidity, high strength development, and corrosion by slag. Is preferable because it is less. As the refractory aggregate, it is possible to use ultrafine powder which is a powder having a fine particle size.

Here, the ultrafine powder is a refractory fine powder in which 80% by weight or more of particles having a particle diameter of 10 μ or less, an average particle diameter of 1 μ or less, and a BET specific surface area of 10 m ² / g or more. However, the fluidity of the amorphous refractory material can be ensured, and high strength is exhibited, which is preferable. Specifically, 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. , Colloidal silica, and easily sintered alumina are preferable.

The amount of the refractory aggregate to be used should be appropriately determined depending on the construction site and is not particularly limited, but in 100 parts by weight of the amorphous refractory composed of the alumina cement composition and the refractory aggregate, the fire resistance is The aggregate is preferably 99.5 to 50 parts by weight, and is preferably 98 to 85 parts by weight from the viewpoint of corrosion resistance and strength development.

The method for producing the irregular refractory material of the present invention is not particularly specified, but according to the ordinary method for producing the irregular refractory material, the constituent raw materials are blended in predetermined proportions, Use a mixer such as a V-type blender, a corn blender, a Nauter mixer, a pan-type mixer, and an omni mixer to uniformly mix, or when kneading at a predetermined ratio, directly weigh it into the kneader. Is also possible.

[0056]

EXAMPLES The present invention will be further described below based on examples.

Example 1 Using Al ₂ O ₃ raw material and CaO raw material, the respective raw materials were blended so that the mineral composition in the product would be a predetermined ratio, and the results are shown in Table 1 at 1,500 ° C. by a kiln firing method. A clinker was manufactured. The produced clinker and α-Al ₂ O ₃ were mixed so that the amount of CaO in the alumina cement was about 18% by weight, and 100 parts by weight of this alumina cement added with 100 parts by weight of additive a and additives. Addition of 1.5 parts by weight of an additive consisting of 260 parts by weight of b and 30 parts by weight of additive c was pulverized using a vibrating ball mill and simultaneously heated at 200 ° C. to obtain an alumina cement composition. 20 parts by weight of this alumina cement composition and 80 parts by weight of refractory aggregate α are mixed to give a water / amorphous refractory ratio of 8.
The mixture was kneaded at 7% to produce an amorphous refractory material. Flow value I and heat generation time I of this amorphous refractory at 30 ℃, and 60 ℃
Flow value II and exothermic time II were measured. The results are also shown in Table 1.

<Materials used> Al ₂ O ₃ raw material: high-purity alumina, reagent made by Ishizu Pharmaceutical Co., Ltd. CaO raw material: high-purity calcium carbonate, reagent made by Ishizu Pharmaceutical Co., Ltd. additive a: sodium carbonate, reagent made by Ishizu Pharmaceutical Co., Ltd. additive b : Sodium citrate, reagent made by Ishizu Pharmaceutical Co., Ltd. Additive c: Borax, reagent made by Ishizu Pharmaceutical Co., Ltd. Fire-resistant aggregate α: Sintered alumina, Showa Denko KK, particle size 3 to 1
mm28 parts by weight, 1-0.5 mm17 parts by weight, 0.5-0.3 mm15 parts by weight, 0.3 mm below 14 parts by weight, 45μ below 6 parts by weight Clinker J: Prototype, CA-C ₁₂ A ₇ clinker

<Measurement method> Chemical composition: CaO and Al ₂ O ₃ are analyzed according to JIS R 2522 Mineral composition: Rigaku X-ray diffraction analyzer “RADII
Diffraction intensity ratio d value by "B", CA = 4.67Å, CA ₂ = 4.45Å, C
₁₂ A ₇ = 4.89Å Diffraction line intensity Flow value: According to JIS R 2521, place a flow cone at a predetermined position in the center of the flow table and fill it with an irregular refractory to smooth the surface. Is taken upward, and the diameter of the spread of the irregular refractory material, which is recognized as the longest, and the diameter at right angles to it, are measured in two directions, and the average thereof is expressed in mm to obtain a flow value. Exothermic time: Put a poly beaker containing an indeterminate refractory into an insulating container, insert a resistance thermometer, measure the exothermic time with a recorder, and measure the exothermic curve from the start of kneading to the exothermic peak time. The time was measured and taken as the exothermic time.

[0060]

[Table 1]

Example 2 100 parts by weight of an alumina cement prepared by mixing 60 parts by weight of clinker E and 40 parts by weight of α-Al ₂ O ₃ were mixed with 100 parts by weight of an additive a and an additive as shown in Table 2. Then, the same procedure as in Example 1 was carried out except that the amounts of additives shown in Table 2 were blended. The results are also shown in Table 2.

<Materials used> Additive material d: sodium polyacrylate, manufactured by Nippon Pure Chemical Co., Ltd.

[0063]

[Table 2]

Example 3 To 100 parts by weight of alumina cement, 1.5 parts by weight of an additive consisting of 100 parts by weight of additive a, 260 parts by weight of additive b, and 30 parts by weight of additive c were added, and the heating temperature is shown in Table 3. The same procedure as in Example 2 was performed except that the above procedure was performed. The results are shown in Table 3.
Also described in.

[0065]

[Table 3]

Example 4 Using Clinker E, α-Al ₂ O _{3 in} alumina cement
Was carried out in the same manner as in Example 1 except that the ingredients were blended as shown in Table 4. The results are also shown in Table 4.

[0067]

[Table 4]

Example 5 Example 1 was repeated except that the amount of refractory aggregate in 100 parts by weight of the amorphous refractory was changed to that shown in Table 5 using Clinker E.
I went the same way. The results are also shown in Table 5. When 8 parts by weight of the alumina cement composition and 92 parts by weight of the refractory aggregate β were mixed and kneaded at a water / irregular refractory ratio of 6%, 10 parts by weight of the alumina cement composition and the refractory aggregate γ were further mixed.
The same procedure was carried out when 90 parts by weight were mixed and kneaded at a water / irregular refractory ratio of 6.5%. The results are also shown in Table 5.

<Materials to be used> Refractory aggregate β: particle size 10 to 5 mm 23 parts by weight, 5 to 3 mm 14 parts by weight, 3 to 1 mm 20 parts by weight, and 1 to 0 mm 12 parts by weight Spinel manufactured by Sumitomo Chemical Co., Ltd. and 220 mesh under 18 Showa Denko's mixture of 5 parts by weight and 5 parts by weight under 325 mesh Refractory aggregate γ: Grain size 5 to 3 mm 20 parts by weight, 3 to 1 mm 15 parts by weight, and 1 to 0 mm 45 parts by weight Showa Denko company Sintered alumina manufactured by Ube Chemical Co., Ltd. with a grain size of 1 mm or less 10
A mixture of 1 part by weight and 1.0 part by weight of silica gel fume manufactured by Elchem Co. with a particle size of 1 mm or less.

[0070]

[Table 5]

Example 6 The same procedure as in Example 2 was repeated except that 100 parts by weight of the alumina cement and 100 parts by weight of the additive a and 1.5 parts by weight of the additive shown in Table 6 were blended. The results are shown in Table 6.
Also described in.

<Materials used> Additive e: boric acid, a reagent manufactured by Ishizu Pharmaceutical Co., Ltd. additive f: potassium borate, a reagent manufactured by Ishizu Pharmaceutical Co., Ltd. additive g: polyacrylic acid, manufactured by Nippon Pure Chemical Co., Ltd. additive h: poly Methacrylic acid, manufactured by Nippon Pure Chemical Co., Ltd. Additive i: sodium polymethacrylate, manufactured by Nippon Pure Chemical Co., Ltd.

[0073]

[Table 6]

Example 7 Example 2 was repeated except that 100 parts by weight of alumina cement, 100 parts by weight of additive a, 30 parts by weight of additive c, and 1.5 parts by weight of the additive shown in Table 7 were used. I went the same way. The results are also shown in Table 7.

<Materials used> Additive j: citric acid, a reagent manufactured by Ishizu Pharmaceutical Co., Ltd. additive k: tartaric acid, a reagent manufactured by Ishizu Pharmaceutical Co., Ltd. additive 1: sodium tartrate, a reagent manufactured by Ishizu Pharmaceutical Co., Ltd. additive m: gluconic acid, Ishizu Pharmaceutical Reagent Additive n: Sodium Gluconate, Ishizu Pharmaceutical Reagent

[0076]

[Table 7]

Example 8 Using the irregular refractory material produced in Example 1, 4 × 4 × 16
A cm test piece was molded and cured at 60 ° C., and the curing strength, dry strength, and firing strength were measured. Table 8 shows the results.

<Measurement method> Curing strength: According to JIS R 2553, 4 ×
After placing it in a 4 x 16 cm mold and flattening the surface with a cement knife, measure the strength after curing for 24 hours Drying strength: After drying the test specimen after curing for 24 hours at 110 ° C for 24 hours, room temperature Allow to cool and measure the strength. Firing strength: Dry the test sample in a silicon knit electric furnace.
After raising the temperature to 800, 1,000, 1,200, and 1,400 ℃,
Hold for 2 hours, let cool to room temperature, and measure strength

[0079]

[Table 8]

Example 9 Example 8 was repeated except that the irregular refractory material produced in Example 2 was used. The results are shown in Table 9.

[0081]

[Table 9]

Example 10 The procedure of Example 8 was repeated except that the irregular refractory material prepared in Example 3 was used. The results are shown in Table 10.

[0083]

[Table 10]

Example 11 The procedure of Example 8 was repeated except that the irregular refractory material prepared in Example 4 was used. The results are shown in Table 11.

[0085]

[Table 11]

Example 12 Example 8 was repeated except that the amorphous refractory material produced in Example 5 was used. The results are shown in Table 12.

[0087]

[Table 12]

Example 13 Example 13 was repeated except that the irregular refractory material produced in Example 6 was used. The results are shown in Table 13.

[0089]

[Table 13]

Example 14 Example 14 was repeated except that the irregular refractory material produced in Example 7 was used. The results are shown in Table 14.

[0091]

[Table 14]

Example 15 Using the amorphous refractory material produced in Example 1, 4 × 4 × 16 cm
The test piece of No. 1 was molded, and the corrosion resistance to slag and the thermal shock resistance by repeating heating-cooling operations were measured. The results are also shown in Table 15.

<Measurement method> Corrosion resistance: A molded specimen is aged at 60 ° C. for 24 hours,
In accordance with JIS R 2214, a hole of φ2 × 2 cm was opened, slag was put in it, held at 1,500 ° C for 2 hours in a silicon knit furnace, and then naturally cooled. After cooling, measure the area of the part that is eroded and melted by dividing it from the center of the hole. Thermal shock resistance: Molded specimens are specified in Refractory Technology Association Standard J
According to RS 2118, hold in a silicon knit furnace at 1,500 ° C for 3 hours and let it cool naturally. Repeat this heating-cooling operation and measure the number of cracks

[Table 15]

Example 16 Example 16 was repeated except that the amorphous refractory material produced in Example 2 was used. The results are also shown in Table 16.

[0095]

[Table 16]

Example 17 Example 17 was repeated except that the irregular refractory material produced in Example 3 was used. The results are also shown in Table 17.

[0097]

[Table 17]

[0098]

When the alumina cement composition of the present invention is used, high fluidity, high strength development,
An amorphous refractory having good corrosion resistance, wear resistance, spalling resistance, etc. can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C04B 35/66 C04B 35/66 B NT

Claims (2)

[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%
100 to 400 parts by weight of alumina cement consisting of 70 to 50 parts by weight of clinker and 30 to 50 parts by weight of α-Al ₂ O ₃
Alkali metal carbonates, carboxylic acids, which were heat treated at ℃,
An alumina cement composition comprising 0.5 to 2.5 parts by weight of three or more additives selected from the group consisting of boric acids and polyacrylic acids. 2. An amorphous refractory material comprising the alumina cement composition according to claim 1 and a refractory aggregate.