JPH09165240A - Alumina cement and monolithic refractory using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain alumina cement securing unconventionally high fluidity and long pot life, and to obtain monolithic refractory by using this alumina cement. SOLUTION: This alumina cement comprises 50-90 pts.wt. of alumina cement material having the following mineral composition: 20-80wt.% of CaO.Al2 O3 , 5-50wt.% of CaO.2Al2 O3 and 60-5wt.% of 2CaO.Al2 O3 .SiO2 , and 50-10 pts.wt. of α-Al2 O3 . The other objective monolithic refractory comprises this alumina cement and refractory aggregate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alumina cement and an amorphous refractory material using the same, and more particularly to an alumina cement and an amorphous refractory material using the same which secures high fluidity and pot life which are not available in conventional products. Regarding

INDUSTRIAL APPLICABILITY The alumina cement of the present invention and the amorphous refractory material using the same can be used in the fields of refractory materials in which alumina cement is used, linings of chemical plants, corrosion resistant materials, and civil engineering fields. .

[0003]

[Prior art and its problems] Alumina cement is CaO
_{Al 2 O 3, CaO · 2Al} 2 O 3, and mineral composition of hydraulic calcium aluminate represented as 12CaO · 7Al ₂ O ₃ or the like is blended with various raw materials such that the main melting and / or calcined to The produced clinker is a hydraulic cement obtained by pulverizing the clinker alone, or a hydraulic cement obtained by pulverizing the clinker with alumina and various additives (Keiichi Akiyama, Chemistry of Cement and Concrete; p234-235, 1984). In addition, various methods for producing general alumina cement and characteristics of mineral composition contained in alumina cement have been proposed (TDRobson; High Alu
mina Cements and Concrete, p1〜45,1962, Refractory, Vol.
29, p368 ~ 374, 1977, Trans.J.Br.Ceram.Soc.; Vol.81
(2), 1982, and Refractories, Vol. And, since SiO ₂ is mixed from various raw materials, alumina cement was studied by variously mixing calcium aluminate shown in the phase diagram of CaO-Al ₂ O ₃ -SiO ₂ ternary components (TDRobson; Hith. Alumina Cements and Concrete, p1
~ 45,1962, JP-A-49-32921, JP-A-52-111920
Japanese Patent Laid-Open No. 4-77339, etc.).

12CaO ・ 7Al_TwoO_ThreeThe ones containing
There is a problem that the_TwoO_ThreeAnd 2
CaO / Al_TwoO_Three・ SiO_TwoRetarder for alumina cement
Was proposed, but it was satisfactory in terms of pot life and liquidity.
It was not one (Japanese Patent Laid-Open No. 63-103847). Conventionally,
To secure the fluidity and pot life of alumina cement,
Specific ratio of CaO ・ Al_TwoO_ThreeAnd CaO / 2Al_TwoO_ThreeMineral composition and additives
Alumina cement using both and was proposed (Japanese Patent Laid-Open No. 2-
175638, JP 7-232941, JP 7-
232956, etc.). It also has high fire resistance and high fluidity.
Alumina cement composition as CaO ・ Al _TwoO_Three, CaO / 2Al
_TwoO_Three, And 12CaO ・ 7Al_TwoO_ThreeHydraulic calcium aluminum
Α-Al _TwoO_ThreeOr add hydro-oxygen as needed.
Sicarboxylate, polyacrylate, and alkali metal
A mixture of carbonate and the like has been proposed (Japanese Patent Publication No. 50-2).
8090, JP 50-102617, and JP 53-
114826 publication). However, this alumina cement
Is required to cure within a certain time
However, as a mineral composition, CaO ・ Al_TwoO_ThreeAnd CaO / 2Al_TwoO_ThreeIncluding
Therefore, if the construction temperature is low, there is a significant hardening delay.
However, there is a problem that it is difficult to cure within a certain time.
Was.

Further, an irregular shaped refractory which can be applied by vibration-free (self-leveling) using alumina cement and an aggregate having a specific particle size has been proposed (JP-A-4-260673 and JP-A-5-180689). Japanese Patent Laid-Open No. 7-237977, etc.). However, there has been a problem that the fluidity of the amorphous refractory cannot be improved by the grain size constitution of the aggregate and the combined use of the additives.

Alumina cements described in these patents and documents cannot be secured a pot life when trying to obtain strength development, and Al ₂ O _{3 is used in} order to obtain high fire resistance.
If the content is increased, there are problems such as a decrease in fluidity and a lack of strength development, and it was not possible to exceed the conventional quality level.

On the other hand, in the refractory field, which is the main application of alumina cement, there is a tendency for the range of application of amorphous refractories containing alumina cement to increase, and the method for constructing irregular refractories is being labor-saving. Therefore, for example, a large amount of kneading, a construction by pumping, a self-leveling construction, a non-vibrator construction and the like, which are carried out when the amount of construction per time exceeds 10 tons, have become popular. for that reason,
In particular, for the purpose of high strength development and high density, alumina cement, ultrafine powder such as silica fume, and amorphous refractory compounded with a dispersant, as its application range increases,
The problem of lack of pot life has become serious.

Further, when alumina cement and water are mixed, Ca ²⁺ , Al ³⁺ , Mg ²⁺ , Na ⁺ , K ⁺ , and Al ₂ O ₄ are converted from the hydraulic calcium aluminate constituting the alumina cement.
^2- Ions etc. elute. Applying the theory of coagulation hardening of the eluted ions and ultrafine powder, various technical reports have been reported on the agglomeration and securing of the pot life of amorphous refractory, especially amorphous refractory containing ultrafine powder. (Refractory,
33-59, p3 to 7,1981, refractory, 33-393, p31 to 34,1981, and refractory, 40-5, p270 to 278, 1988).

Since the hydration of alumina cement proceeds by the ions eluted in the liquid phase after water injection, based on the DLVO theory that models the agglomeration and dispersion of colloids, in the case of amorphous refractories, the agglomeration is based on the amount of eluted ions. There is a problem that it becomes difficult to secure the fluidity and the pot life in a high temperature construction atmosphere because the speed depends on it. The DLVO theory here is the theory of stability of colloids (Verwey, EJWet.; Theror
y of the Stability of Lyophobic Colloids; Elsevier.
New york., 1948) based on the close relationship between the rheological properties of the suspension and the dispersion and aggregation of the ultrafine powder. It shows the relationship of electrostatic repulsion potential. According to this theory, the higher the concentration of the electrolyte, and the higher the ionic value of the electrolyte, the more the aggregation is promoted. Ca eluted from alumina cement
^Polyvalent ions such as ²⁺ and Al ₂ O ₄ ^2- give the amorphous refractory a cohesive property, and the coagulation is accelerated, so that the fluidity is lowered and the pot life is shortened. Therefore, the conventional alumina cement has a problem that the control of polyvalent ions is insufficient and the fluidity and the pot life cannot be secured.

In particular, in the construction by pumping for the purpose of labor saving in construction, construction by a concrete mixer truck, etc., non-vibrator construction, etc., the fluidity of the amorphous refractory is very important, In the conventional alumina cement, there were problems such as not being able to secure fluidity and pot life, solidifying in the mixer, and being unable to discharge from the hopper.

Further, in recent years, the property as an irregular shaped refractory adapted to various construction methods has been required, and there is a problem that conventional alumina cement cannot secure sufficient fluidity and pot life.

Further, the mineral composition of conventional alumina cement has been limited to those mainly composed of CaO.Al ₂ O ₃ in terms of ensuring appropriate fluidity and imparting strength development and hardening properties.
In particular, the calcium aluminate, characteristics change by CaO / Al ₂ O ₃ molar ratio, or decrease refractoriness the CaO / Al ₂ O ₃ molar ratio increases, or show rapid hardening, CaO / Al ₂ It is generally known that when the O ₃ molar ratio is small, high fire resistance and curing retardation are exhibited.

Further, SiO ₂ and Ti derived from raw material impurities
Chemical components such as O ₂ , Fe ₂ O ₃ and MgO have a problem that when they are used in an amorphous refractory, they form a low melting point compound, which lowers the fire resistance and hot strength.

On the other hand, in order to adjust the curing rate of calcium aluminate, it has been proposed to incorporate a fast-curing calcium aluminate such as 12CaO.7Al ₂ O ₃ (JP-A-54).
-13639 publication). In addition, CaO ・ 2Al ₂ O ₃ and 3CaO ・ 5Al ₂ O ₃ are
Although it has a high refractory property, it has a problem that the curing delay is large, and as a balance of fluidity, curability, and strength development, CaO ・ Al ₂ O ₃ , CaO ・ 2Al ₂ O ₃ , and 12CaO ・7
Alumina cement in which Al ₂ O ₃ is mixed has been proposed (JP-A-7-61844, etc.).

Furthermore, when these conventional alumina cements are used in low cement castables, the elution amount of ions such as Ca ²⁺ , Al ³⁺ , Al ₂ O ₄ ²⁻ and OH ⁻ from the alumina cement is reduced. For the purpose of ensuring the pot life, alumina cement having a changed particle size distribution and alumina cement having a horny or scaly particle shape have been proposed (JP-A-5
8-36953 and JP-A-61-2200). However, even if the particle size distribution or particle shape of the alumina cement is changed, the elution control of polyvalent ions due to calcium aluminate is insufficient, and the fluidity and the pot life cannot be secured sufficiently.

When alumina cement is used in the field of refractories, those containing SiO ₂ are inferior in fire resistance, so
SiO ₂ is not _{incorporated, 2CaO · Al 2 O 3 ·} SiO produced by SiO ₂ present in the raw material bauxite, etc., used during the alumina cement production as a by-product of calcium aluminate
It remains in the amount of ₂ and its CaO ・ Al ₂ O ₃・ SiO ₂ is
Since its hydration activity is extremely low and it shows a decrease in fire resistance, it has never been used as an alumina cement positively.

As a technique in which an additive is used in combination for the purpose of ensuring fluidity and pot life, for example, CaO.Al at a specific ratio is used.
₂ O ₃ , 12CaO.7Al ₂ O ₃ , and amorphous, α-Al ₂ O ₃ ,
Hydroxycarboxylic acid, and an alumina cement composition comprising an inorganic carbonate (Japanese Patent Publication No. 45-129562).
JP-A-49-32921, JP-A-50-102617, JP-A-55-121933, etc.), water-soluble polyacrylic acid and / or methacrylic acid-acrylic acid copolymer and alkali metal Alumina cement containing carbonate
(JP-like 55-75947 and JP 55-75948 discloses), alumina cement containing amorphous with specific CaO / Al ₂ O ₃ molar ratio, or CaO · Al ₂ O _3, CaO ・ 2Al ₂ O ₃ , 3Ca
Alumina cement mainly composed of amorphous calcium aluminate corresponding to one or more mineral compositions of O ・ Al ₂ O ₃ , 12CaO ・ 7Al ₂ O ₃ , and 11CaO ・ 7Al ₂ O ₃・ CaF ₂ ( JP 61
-132556, JP 61-77659, and JP 2
-175638), at least 80% by weight or more of CaO
Al ₂ O ₃ of clinker and alumina cement comprising the alumina for a particular specific surface area, or alumina cement clinker comprising an alumina fine powder of alumina cement (JP 52-111920 JP and Sho 43- such as 74896 JP), CaO · 2Al ₂ O ₃ to be mainly 12CaO · 7Al ₂ O _3, fine alumina, and alumina cement (JP 55-144456 discloses that by blending a sulfonic acid anionic surfactant And JP-A-55-121934), a specific ratio of CaO ・ Al ₂ O ₃ and CaO.
・ Alumina cement composed of clinker containing 2Al ₂ O ₃ and α-Al ₂ O ₃ (USP 4162923), calcium aluminate, polyacrylic acid, boric acid, and cement composition composed of carbonate or carboxylic acid However, when applied to low-cement castables, there was a problem that the working time could not be secured at the time of high-temperature construction and the fluidity could not be sufficiently secured.

Usually, commercially available alumina cements are mainly composed of CaO.Al ₂ O ₃ , and depending on the required characteristics, 12CaO.7Al
_It contains ₂ O ₃ , α-Al ₂ O ₃ , additives and the like, and contains a small amount of CaO · 2Al ₂ O ₃ as a by-product during the production of clinker.

Al using natural raw materials such as bauxite
Mina cement contains 2CaO ・ Al_TwoO_Three・ SiO _TwoCan be seen
However, it is just the amount as an impurity, and
There was no positive composition adjustment in the mineral composition.
(Refractory Vol.29, p368 ~ 374,1977, Refractory Vol.34, p634
~ 640,1982). In addition, high-purity alumina and aluminum hydroxide
With alumina cement that uses synthetic raw materials such as um,
SiO_TwoWhen it contains SiO, there is a problem that the fire resistance decreases,_TwoIs
Actively excluded, various mineral compositions as in the present invention
By combining_Two2CaO ・ Al containing_TwoO_Three・ SiO
_TwoNothing elicited the characteristics of mineral composition. And
In these alumina cements, refractory fields, especially
Amorphous resistance required in steel fields such as pig iron and steel making equipment
The characteristic level of the fire is the fluidity, strength development, fire resistance,
In addition, there is a problem that the corrosion resistance is insufficient.

Meanwhile, as a prior art, for _{example, CaO · Al 2 O 3,} CaO · 2Al 2 O 3 contained in the alumina cement, and 12C
Studies on calcium aluminate such aO · 7Al ₂ O ₃ is observed many, research although Among them CaO · 2Al ₂ O ₃ from the exhibit set retarding tendency to contain CaO · 2Al ₂ O ₃ as the prior art (Cement and Concrete research; Vol.
20, p623 ~ 635,1990, Trans.J.Br.Ceram.Soc.; 81 (2), p3
5 to 42,1982, and refractories, No. 11, p18 to 24,1982). However, there was a problem that the fluidity and pot life could not be sufficiently secured when used for an actual amorphous refractory.

In order to improve the long-term strength of alumina cement, a method of mixing steel slag powder containing 2CaO.Al ₂ O ₃ .SiO ₂ has been proposed (Japanese Patent Laid-Open No. 53-12926 and Japanese Patent Laid-Open No. 12926). (Kaisho 60-5055, etc.). However, when it is used for an irregular shaped refractory, there is a problem that not only the fluidity and the pot life cannot be sufficiently secured, but also the fire resistance is insufficient and the strength at high temperature is insufficient.

As a result of various studies to solve the above problems, the present inventor can solve the above problems by using alumina cement having a specific mineral composition, and in particular, it is required as an amorphous refractory material. The present invention has been completed based on the knowledge that various properties such as fluidity, pot life, curability, and strength development can be satisfied.

[0023]

[Means for Solving the Problems] That is, the present invention is directed to CaO.Al.
A _{2 O 3, CaO · 2Al 2} O 3, and alumina cement comprising a 2CaO · Al ₂ O ₃ · Alumina cement materials and α-Al ₂ O ₃ comprising the SiO ₂ of the mineral composition, proportion of mineral composition of the alumina cement material, CaO · Al ₂ O ₃ 20~80 wt%, CaO · 2
Al ₂ O ₃ 5 to 50% by weight, and 2CaO · Al ₂ O ₃ · SiO ₂ 5 to 60% by weight
Is an alumina cement, which is an alumina cement material
It is an alumina cement containing 50 to 90 parts by weight and α-Al ₂ O ₃ 50 to 10 parts by weight, and is an amorphous refractory material containing the alumina cement and refractory aggregate.

Hereinafter, the present invention will be described in detail.

The alumina cement material used in the present invention comprises CA, CA ₂ , and C ₂ AS as mineral compositions, where CaO is C, Al ₂ O ₃ is A, and SiO ₂ is S. Alumina containing CA, CA ₂ and C ₂ AS, wherein CA is 20 to 80% by weight, CA ₂ is 5 to 50% by weight, and C ₂ AS is 5 to 60% by weight. It is a cement material, and the content of this particular mineral composition is important. That is, in the prior art, when the constituent component of the alumina cement is a significant retardation of hardening, a decrease in strength development, and unfavorable C ₂ AS causing a decrease in fire resistance, a specific ratio of CA and CA ₂ is used in combination. As a result, the fluidity can be secured and the pot life can be extended without causing a significant delay in curing or a decrease in strength development.

The alumina cement substance is a high-purity alumina obtained by refining a CaO raw material such as limestone or quick lime or a natural raw material such as red bauxite by a refining method such as the Bayer process, bauxite, and Al ₂ such as aluminum residual ash. O ₃ raw materials and SiO ₂ raw materials such as silica sand, fused silica, clay, loess, and chamotte are blended so that the mineral composition in the heat-treated product will be a predetermined ratio, and the electric furnace, reverberatory furnace, vertical furnace The clinker obtained by melting and / or firing is pulverized in equipment such as a mold furnace, open hearth furnace, shaft kiln, and rotary kiln.

In the present invention, it is preferable to manufacture the clinker by a melting method, which makes it easier to manufacture the mineral composition ratio of calcium aluminate within the purpose of the present invention, as compared with the clinker manufactured by the firing method. When manufacturing an alumina cement material by the melting method, CaO raw material, Al ₂ O ₃ raw material, and SiO ₂ raw material are mixed and / or mixed and pulverized at a predetermined ratio, and an electric furnace, open hearth furnace,
Alternatively, it is preferably melted at a high temperature of 1,500 ° C. or higher in a melting furnace such as a reverberatory furnace, and more preferably melted until the unreacted raw materials are completely consumed. After the raw material mixture is melted, it is preferably brought into contact with high-pressure air or water and cooled to be used as a clinker of alumina cement. Crush these clinker
As for the mixing, the clinker may be mixed and then crushed, or each crushed product may be mixed, and the means for obtaining the desired mineral composition ratio is not particularly limited. As the crusher for clinker, it is possible to use a crusher such as a roller mill, a jet mill, a tube mill, a ball mill, and a vibration mill, which is usually used for finely pulverizing powder lumps.

As a method for obtaining the mineral composition intended by the present invention, a method of synthesizing CA-CA ₂ -C ₂ AS mineral composition at a time, C
A, CA ₂ and C ₂ AS mineral compositions are individually synthesized and compounded so as to have a predetermined ratio, and CA-C ₂ AS mineral composition, CA ₂ -C ₂ AS mineral composition, CA, There is a method of synthesizing a clinker containing CA ₂ and C ₂ AS mineral compositions and mixing them so as to obtain a predetermined mineral composition.

The blending ratio of the mineral composition in the present invention is Cu
It can be analyzed by X-ray diffraction analysis using -Kα ray. As a method for quantifying the mineral composition by the X-ray diffraction method, there are a diffraction line intensity ratio measuring method, an internal standard method, a Zevine method, an X-ray diffraction peak separation method, and the like, and in the present invention, any method can be quantified. is there. The diffraction line intensity ratio measurement method referred to here is a value that relatively expresses the diffraction intensity of each mineral composition.The internal standard method is a method in which an internal standard substance and a sample are mixed at a fixed ratio. This is a method of creating and analyzing a calibration curve using a standard sample of known concentration, utilizing the fact that a linear relationship is obtained between the component concentration and the diffraction line intensity ratio. Also,
The Zevine method is a method in which the average mass absorption coefficient of a sample and the diffraction line intensity ratio are measured, and each crystal phase is quantified by solving a simultaneous equation of order n. The average mass absorption coefficient is a fluorescent X-ray analysis method. Alternatively, the components of the sample can be quantified and calculated by chemical analysis. In addition to this, it is also possible to perform quantification by an X-ray diffraction peak separation method in which measurement is performed from the crystal or glass phase of the sample. In the present invention, the mineral composition and the vitrification rate can be quantified by any of the methods, but the Zevine method or the diffraction line intensity ratio measurement method, which are simple and accurate, are preferable.

The mineral composition ratio of the alumina cement material is
CA 20-80 parts by weight, CA_Two5 to 50 parts by weight, and C_TwoAS 5-60 layers
The amount is preferably 40 to 60 parts by weight, CA_Two10-30 parts by weight,
And C _TwoAS 10 to 30 parts by weight is more preferable. Alumina cement
If the mineral composition ratio of the material is outside this range, fluidity and hardness
The chemical conversion and strength development may deteriorate, and C_TwoAS included
If the content is large, the strength will decrease and the curing delay will be large._Two
When the amount is small, the amount of aluminum hydroxide produced after hydration is small
When used as an irregular refractory
The strength in the temperature range may decrease. Also, a certain amount
If CA is not contained, the strength is insufficient, and therefore,
CA, CA_Two, And C_TwoThe mineral composition ratio of AS is important.

Further, in the present invention, the chemical composition of the alumina cement material is 10 to 40% by weight of CaO, 60 to 80% by weight of Al ₂ O ₃ ,
And SiO ₂ is preferably 0.6 to 20 wt% from the viewpoint of strength development and fire resistance, CaO 20 to 30 wt%, Al ₂ O ₃ 50 to 70
It is more preferable that the content is wt% and SiO _{2 is} 1 to 10 wt%. If the chemical components are out of this range, the pot life cannot be sufficiently secured, and the strength developability may deteriorate. The alumina cement material of the present invention includes the target CA, CA ₂ , and C ₂ AS.
In addition, it is possible to use those containing impurities such as α-Al ₂ O ₃ originating from the raw material and CaO ・ TiO ₂ and 4CaO ・ Al ₂ O ₃・ Fe ₂ O ₃ generated from impurities in the raw material. However, it is preferable that the amount of impurities in the alumina cement substance is small, and the total amount is 5
Weight% or less is preferable, TiO ₂ 0.5 weight% or less, Fe ₂ O ₃ 0.5
More preferably, the content is not more than wt% and the content of MgO is not more than 0.5 wt%. If these impurities increase, not only the fire resistance but also the properties such as strength development, volume stability as a cured product at high temperature and spalling resistance will deteriorate, and corrosion resistance to slag etc. will decrease. There are cases.

The vitrification rate of the alumina cement material in the present invention can be adjusted by the rate of cooling the melted and / or fired high temperature clinker, and is not particularly limited. A high rate is preferable because a long pot life can be obtained. The vitrification rate can be measured by analyzing the mineral composition by a powder X-ray diffraction method, and the weaker the intensity of the diffraction line, the higher the vitrification rate. In the present invention, the vitrification rate is preferably 20% or more,
50% or more is more preferable. This vitrification rate can be measured by the disappearance of the diffraction line by the powder X-ray diffraction method, and is calculated by the formula of vitrification rate (wt%) = 100− (peak area / total diffraction line area) × 100. it can. Alumina cement is generally produced by a method in which a clinker produced by melting or firing is brought into contact with water or air to cool it, but if it is rapidly cooled during cooling, the vitrification rate becomes high, and the SiO ₂ content in the mineral composition of the clinker is high. The higher the content, the higher the vitrification rate.

Since the particle size of the alumina cement substance or the alumina cement affects the fluidity, the hardening property and the strength development property, it is an important control point for obtaining the target characteristics, and the particle size of the crushed clinker is For example, JIS R 2521
It can be measured by the method for measuring the Blaine specific surface area described in, the Blaine value is preferably 2,000 to 8,000 cm ² / g, 4,000 to 7,000 cm ²
/ g is more preferable. If it is less than 2,000 cm ² / g, the hydration activity as an alumina cement substance or an alumina cement is low, and the strength development property may be deteriorated or curing failure may occur. If it exceeds 8,000 cm ² / g, the hydration activity will be too large and the pot life after water injection may not be secured. Further, the average particle diameter is preferably 20 μm or less because of excellent fluidity and pot life at high temperature, and more preferably 1 to 15 μm. If it exceeds 20μ, the fluidity may decrease or the curing may be delayed. The average particle size here is the value of the particle size measurement result by a commonly used particle size distribution measuring instrument such as laser diffraction method, laser scattering method, and sedimentation balance method, and is a 50% average diameter. .

In the present invention, the alumina cement material is α-A.
l ₂ O ₃ is mixed and used as an alumina cement.

Α-Al ₂ O ₃ imparts high fire resistance, high temperature strength development, and volume stability when the alumina cement of the present invention is used for an irregular shaped refractory, and is high by a Bayer process or the like. Purified alumina obtained by firing purified aluminum hydroxide in a rotary kiln, Al ₂ O ₃ is a high-purity alumina containing 90% by weight or more, generally, high-purity alumina, Bayer alumina,
It is called easily sinterable alumina or light burned alumina, and the characteristics of the alumina cement largely change depending on the type of α-Al ₂ O _{3 to be} mixed, so the selection of α-Al ₂ O ₃ is important. In particular, in the present invention, it is possible to exhibit the characteristics which the conventional products do not have until the interaction with the alumina cement substance to be combined.

Regarding the particle size of α-Al ₂ O ₃ , the primary particle size before crushing is the average particle size (Dp50), and preferably 30 to 100 μm. Usually, the primary particle size is related to the deposition rate of aluminum hydroxide in the Bayer process, and when the deposition rate is reduced, a large diameter is obtained, and when it is increased, a small diameter is obtained. The degree of calcination is 0.2 to 1 in terms of specific surface area by the BET method.
00m ² / g is preferred. The degree of calcination indicates that the larger the specific surface area, the lighter the type of alumina, and when used at high temperatures, it has excellent sinterability, but also has the drawback of large shrinkage. If the specific surface area 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. A mixture of alumina with a small specific surface area
It shows the opposite tendency. Therefore, the selection of alumina to be blended in the present invention greatly affects the characteristics of the alumina cement, and therefore should be carefully performed, and should be appropriately determined depending on the required quality when blended in the amorphous refractory. However, in the present invention, the primary particle size of α-Al ₂ O ₃ is 30 to 100μ, the firing degree of alumina is preferably 0.2 to 100 m ² / g, the primary particle size 40
~ 80μ, more preferably 0.3 ~ 10m ² / g, in terms of fluidity, curability, strength development, shrinkage, and spalling resistance, the primary particle size is 45 ~ 65μ, the degree of baking 0.35 ~. Most preferred is 2 m ² / g.

Further, the purity of α-Al ₂ O ₃ is Al ₂ O ₃ 9 if alumina produced by a usual Bayer process is used.
It is possible to secure a purity of 8% by weight or more. In the present invention, A
The purity of l ₂ O ₃ has never been higher, but 98% by weight
The above is enough. In α-Al ₂ O _3, a Na ₂ O content of the impurities is a problem in addition to the Al ₂ O ₃ purity, when the alumina cement Na ₂ O is large, problems such as reduction of the fluidity, refractory May decrease or shrink at high temperature. Therefore, the amount of Na ₂ O is preferably small, preferably 0.5% by weight or less, and more preferably 0.35% by weight or less.

In the present invention, the α-Al ₂ O ₃ and clinker of alumina cement are blended and mixed and pulverized by a pulverizer, or α-Al ₂ O ₃ alone is pulverized to a particle size corresponding to alumina cement, It is also possible to mix the crushed clinker with, for example, a Nauta mixer or a pan mixer. α-A
When pulverizing l ₂ O ₃ alone, it is preferable to pulverize to a Dp50 of about 1 to 10 μm. In the present invention, it is better to mix and grind α-Al ₂ O ₃ with a clinker, because it is more compatible with the alumina cement particles, and because it is uniformly mixed in the alumina cement, when used for an amorphous refractory, a cured product The structure tends to be uniform and corrosion resistance tends to improve.

The amount of α-Al ₂ O ₃ used is 1 in 100 parts by weight of alumina cement composed of the alumina cement substance and α-Al ₂ O _3.
0 to 50 parts by weight is preferable, and 20 to 40 parts by weight is more preferable. When the amount of α-Al ₂ O ₃ used is increased, the fire resistance and the firing strength at high temperature increase, but the curing strength at room temperature and the dry strength tend to decrease, and the fluidity also tends to decrease. Although there is a balance with the component composition of, the chemical composition ratio after blending α-Al ₂ O ₃ is CaO 10 to 30% by weight, Al ₂ O ₃ 70 to 90% by weight,
And SiO ₂ is preferably added in an amount of 0.6 to 10% by weight. In particular, in the present invention, the composition of CaO 21 to 28% by weight, Al ₂ O ₃ 70 to 78% by weight, and SiO ₂ 1 to 6% by weight has good fluidity and high strength. It is more preferable from the viewpoint of obtaining expressibility. When CaO or SiO ₂ is large, the corrosion resistance and fire resistance tend to be significantly reduced. In the case of irregular shaped refractory containing magnesia aggregate as refractory aggregate, if α-Al ₂ O ₃ in alumina cement is large, it may react with magnesia at high temperature to form magnesia spinel. Since α-Al ₂ O ₃ in alumina cement exceeds 80% by weight, it is necessary to mix a large amount of α-Al ₂ O ₃ in alumina cement because it tends to expand in volume during the process. It is not preferable depending on the addition amount.

Further, in the present invention, for the purpose of improving the fluidity of the alumina cement or the amorphous refractory, it is usually blended with the irregular refractory, for example, refractory, 33-59, p3-7, 1981, Refractory, 33-393, p31-34, 1981, and Refractory, 40-5, p270-278,
It is possible to use additives such as a curing retarder and a curing accelerator described in 1988 etc., and a fluidizing agent in combination.

Examples of the curing retarder include carboxylic acids, alkali metal carbonates, boric acids, polyacrylic acids, polymethacrylic acids, and phosphoric acids, of which carboxylic acids or alkali salts thereof are preferably used.

Here, the carboxylic acids are oxycarboxylic acids, and specifically, citric acid, gluconic acid,
Examples thereof include tartaric acid, succinic acid, lactic acid, malic acid, and salicylic acid, or their alkali salts such as sodium salt, potassium salt, and calcium salt. Among these, use of citric acid or an alkali salt thereof, particularly sodium citrate or potassium citrate, is preferred. The purity of the carboxylic acids is not particularly limited, but currently industrially purified carboxylic acids can be used, and the purity of the target carboxylic acids is preferably about 80% by weight or more. Among them, citric acid containing 0.05% by weight or less of sulfate as an impurity or a salt thereof, or citric acid having a pH of 7 to 10 of a 1% by weight concentration aqueous solution at 20 ° C. or a salt thereof is It is preferable because it is excellent.

As the alkali metal carbonate, any of inorganic carbonates can be used, but it is preferable to use alkali metal carbonates such as sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, and the like. Either salt or anhydrous salt can be used. Of these,
Use of sodium carbonate is preferred, JIS K 1201 and JIS K 8
It is possible to use sodium carbonate as defined by 625. The particle size of the alkali metal carbonate is preferably as fine as possible so as to be easily dissolved in water when mixed with alumina cement, and is preferably 100 mesh or less, particularly preferably 200 mesh or less. Although the purity of the alkali metal carbonate is not particularly limited, it is possible to use an industrially refined alkali metal carbonate, and the purity of the target carbonate is about 80% by weight or more. It is preferable to use

The boric acid refers to boric acid or its alkali salt. Boric acid is also called boric acid, orthoboric acid, or orthoboric acid, 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, but usually, sulfuric acid is added to the raw ore of boric acid for thermal decomposition, boric acid is liberated, separated and extracted, and then purified. Examples of the alkali salt of boric acid include a sodium salt, a potassium salt, and a calcium salt. Among them, the use of 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 boric acids is preferably as small as possible so as to be easily dissolved in water when mixed with alumina cement. Further, the purity of boric acids is not particularly limited, but currently industrially purified boric acid can be used, and the BO ₄ content in boric acid is preferably 80% by weight or more.

Examples of the polyacrylic acids include polyacrylic acid and salts thereof such as sodium polyacrylate, potassium polyacrylate, and ammonium polyacrylate. Among these, performance, price, and availability are available. It is most preferable to use sodium polyacrylate because it is easy and easy to handle.

The polymethacrylic acids are polymethacrylic acid or salts thereof, such as sodium polymethacrylate, potassium polymethacrylate, and ammonium polymethacrylate. Among these, performance, price,
It is most preferable to use sodium polymethacrylate because it is easily available and easy to handle.

Examples of the phosphoric acids include hexametaphosphoric acid, tripolyphosphoric acid, pyrophosphoric acid and alkali salts thereof.

Examples of the curing accelerator include hydroxides such as sodium hydroxide, potassium hydroxide and calcium hydroxide, and lithium salts such as lithium carbonate. Of these, use of the lithium salt has a curing promoting action. It is preferable from the standpoint of strength.

The amount of the additive used is 100% alumina cement.
0.5 to 2.5 parts by weight, preferably 1.0 to 2.0 parts by weight
Parts by weight are more preferred. 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.

The fluidizing agent is an admixture containing a surfactant having excellent cement dispersibility as a main component, and is generally a salt of naphthalenesulfonic acid formalin condensate (naphthalene type), melamine resin sulfonic acid formalin condensate. Salt (melamine series) and olefin / maleic acid copolymer salt
(Carboxylic acid type) and the like can be used. Specific examples include sodium salt of β-naphthalene sulfonic acid high condensate, sodium salt of creosote oil sulfonic acid condensate, sodium salt of β-naphthalene sulfonic acid low condensate, and polyoxyethylene nonylphenyl ether. . Although the amount of the fluidizing agent used is not particularly limited, it is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the amorphous refractory made of alumina cement and refractory aggregate.

The method of mixing the additives and the fluidizing agent is not particularly limited, and the additives and the like are mixed in a predetermined ratio, and the alumina cement is crushed in advance, and a V type blender, a corn blender, and a Nauta. Mixing uniformly using a mixer such as a mixer, a pan-type mixer, and an omni mixer, or after mixing alumina cement and additives in a predetermined ratio, a vibration mill, a tube mill, a ball mill, a roller mill, etc. It is possible to mix and pulverize with a pulverizer. In addition, in the present invention, additives such as 100 ~ 4
Heat at a temperature of 00 ° C and mix with alumina cement, or
Alternatively, a method of heating a mixture of additives and the like and alumina cement together is possible. As a heating method, a method of heating at the same time as crushing, a method of heating with hot air during transportation, a method of heating a transportation machine, a method of heating during storage, and the like are possible.

These additives are ICP, ICPA, G
It is possible to specify the kind and the quantitative ratio by instrumental analysis such as C-MS, NMR, HPLC, and FT-IR, chelate analysis, and activation analysis.

The water used in the present invention is not particularly limited, and water used for general concrete such as tap water, natural water and river water can be used, but Na ⁺ , K
^It is preferable to use water having a low content of soluble components such as ⁺ , Mg ²⁺ , Ca ²⁺ , and Cl ⁻ . The amount of water used is appropriately determined depending on the intended amorphous refractory and is not particularly limited,
If the amount is too large, breathing or strength is reduced. Therefore, in the case of the castable amorphous refractory, 2 to 20 parts by weight is usually preferable to 100 parts by weight of the irregular refractory. Generally, it is preferable to add water so that the flow value measured by the method described in JIS R 2553 is 130 to 240 mm.

The refractory aggregate used in the present invention is a refractory aggregate.
It is preferably used for a low cement castable type consisting of 92 to 99% by weight and alumina cement 1 to 8% by weight, and a fireproof aggregate which is usually used for an irregular shaped refractory can be used. Specifically, magnesia such as molten magnesia, sintered magnesia, natural magnesia, and light burned magnesia, magnesia spinel material such as fused magnesia spinel and sintered magnesia spinel, fused alumina, sintered alumina, light burned alumina, and Alumina such as easy-sintering alumina, oil pitch, tar, and carbonaceous material such as scaly graphite, and silica fume, colloidal silica, light-burning alumina, and ultrafine powder such as easy-sintering alumina. Fused silica, calcined mullite, chromium oxide, bauxite, andalusite, sillimanite, chamotte, silica stone, loastone, clay, zircon, zirconia, dolomite, perlite, vermiculite, brick dust, pottery waste, silicon nitride, boron nitride, silicon carbide , And silicon iron nitride can be used. In particular, in the amorphous refractory of the present invention, corrosion resistance, durability (durability), and in terms of fire resistance, magnesia aggregate, magnesia spinel aggregate, alumina aggregate, carbonaceous aggregate, super It is preferable to mix fine powder and one or more kinds of refractory aggregates selected from aggregates such as chamotte and silicon carbide. Further, when used in the molten steel process of the steel manufacturing process, from the aspect of slag permeation suppression, it is preferable to use a magnesia aggregate and an alumina aggregate in combination, or a magnesia spinel aggregate and an alumina aggregate in combination. When used in a process, it is preferable to use an alumina-based aggregate such as fused alumina or sintered alumina and a carbon-based aggregate, ultrafine powder such as silica fume, and additives in combination.

Here, the magnesia-based aggregate is a sintered product obtained by calcining magnesium hydroxide, magnesium carbonate, magnesite which is natural magnesia, or natural magnesium carbonate extracted from seawater by the seawater method in a rotary kiln or the like. Magnesia clinker, also, the electro-melting magnesia clinker obtained by melting the sintered magnesia clinker in an electric furnace or the like, further, crushed a mixture of the sintered magnesia clinker and the electro-melting magnesia clinker into a predetermined size, It is sieved, and the purity of MgO is 80% by weight or more, when it is used for an irregular shaped refractory, it is preferable in terms of excellent corrosion resistance, and those with less impurities such as SiO ₂ and TiO ₂ are preferable. purity is 95 wt% or more, CaO content of from 2 wt% or less, the content of SiO ₂ is 0.5 wt% or less, and B ₂ O ₃ Magnesia Yu rate of 0.5 wt% or less, preferably from the surface of excellent corrosion resistance. In addition to these, magnesia with spinel coating, magnesia containing magnesium titanate at grain boundaries, magnesia with calcium aluminate formed on the surface of magnesia particles, and high purity, high bulk density, and coarseness used for basic bricks Special magnesia clinker with crystal grains, and
It is also possible to use special magnesia obtained by crushing magnesia / zirconia clinker having improved heat-resistant spalling resistance. The MgO / Al ₂ O ₃ molar ratio in the magnesia clinker is preferably 1/1 to 0.1 / 1 and 0.4 / 1 to 0.2 / 1.
Is more preferable in terms of excellent durability when blended with an amorphous refractory.

The magnesia spinel aggregate is a mixture of MgO raw material such as magnesium hydroxide and calcined magnesia and Al ₂ O ₃ raw material such as aluminum hydroxide and calcined alumina in a predetermined ratio. , A rotary kiln or other firing device, spinel clinker reacted and fired at a temperature of about 1,800 to 1,900 ° C, and a magnesia spinel clinker melted in a melting device such as an electric furnace are further fired. A clinker or the like, which is a mixture of the dried product and the melted product, is crushed to a predetermined size and sieved.

The alumina-based aggregate is obtained by melting and / or firing an Al ₂ O ₃ raw material such as aluminum hydroxide or calcined alumina by a melting device such as an electric furnace or a firing device such as a rotary kiln. It was crushed to the size of sieving and sieved, and the mineral composition was α-Al ₂ O ₃ and β.
Aluminum oxide represented by -Al ₂ O _{3 and the} like, which is called sintered alumina, calcined alumina, and easily sintered alumina. Α-containing 90% by weight or more of Al ₂ O ₃
Most preferred is the use of Al ₂ O ₃ . It is also possible to use alumina-zirconia clinker having improved heat resistance spalling property, which is obtained by melting alumina and zirconia clinker.

The refractory aggregate is usually 5 to 3 mm, 4 to 1 mm,
A particle size of 3 to 1 mm, 1 mm, 200 mesh, 325 mesh, etc. is blended according to the required physical properties.

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

Here, the ultrafine powder is a refractory fine powder containing 80% by weight or more of particles having a particle size of 10 μ or less, an average particle size of 1 μ or less, and a specific surface area by the BET method of 10 m ² / g or more. When mixed with amorphous refractory, the fluidity can be secured.
It is preferable because it has high strength developability. 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. It is preferable to use colloidal silica, and easily sintered alumina. In particular, silica fume used for low cement castable is important because the pH of the silica fume when it is made into a slurry influences the dispersibility, and weakly acidic to acidic silica fume is particularly preferable from the viewpoint that the pot life can be secured.

The amount of the refractory aggregate of the present invention to be used should be appropriately determined depending on the construction site and is not particularly limited, but is preferably 50 to 99 parts by weight in 100 parts by weight of the amorphous refractory, From the viewpoint of corrosion resistance, 85 to 90 parts by weight is more preferable. When ultrafine powder such as silica fume is used as a refractory aggregate in low cement castables, the composition of alumina cement 2 to 6 parts by weight, refractory aggregate 94 to 98 parts by weight, and silica fume 5 parts by weight or less is remarkably contained. It is preferable from the viewpoint of ensuring fluidity and pot life.

The method for producing the amorphous refractory material of the present invention is not particularly limited, but according to the ordinary method for producing the amorphous refractory material, the constituent raw materials are mixed in a predetermined ratio and V Uniform blending using a blender such as a mold blender, a corn blender, a Nauter mixer, a pan mixer, and an omni mixer, or when kneading at a predetermined ratio, may be directly weighed in the kneading machine. It is possible.

Furthermore, the amorphous refractory material of the present invention comprises metal powder such as metal aluminum or silicon alloy, organic fiber such as vinyl fiber or polypropylene, for the purpose of preventing explosion which tends to occur when the cured product is dried. A nitrogen-containing gas product and an explosion-proof agent such as dextrin may be added as required. The amount of anti-explosive agent used should be appropriately determined according to the intended explosion resistance, and cannot be uniquely determined, but generally, it is an irregular refractory
It is possible to add 0.05 to 5 parts by weight to 100 parts by weight.

[0064]

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

Example 1 A CaO raw material, an Al ₂ O ₃ raw material, and a SiO ₂ raw material were mixed, melted in an electric furnace, and then rapidly cooled with high-pressure cooling air to synthesize a clinker having a predetermined mineral composition. . 25 parts by weight of α-Al ₂ O ₃ was added to 75 parts by weight of the synthesized clinker, and the mixture was crushed with a batch type ball mill so that the Blaine value was about 4,800 cm ² / g. The inventive alumina cement was produced. 3 parts by weight of this alumina cement, 79 parts by weight of refractory aggregate a having a grain size of 4 to 1 mm, 18 parts by weight of refractory aggregate b having a grain size of 1 mm, 3 parts by weight of refractory aggregate c which is an ultrafine powder, 0.05 part by weight of additive A, and Amorphous refractory was manufactured by adding 0.03 part by weight of additive B. Manufactured amorphous refractory
Add 7.5 parts by weight of water to 100 parts by weight and mix with a mixer.
After kneading for minutes, mineral composition, flow value as fluidity, pot life, curing time, curing strength and dry strength as room temperature strength,
And the firing strength was measured as the high temperature strength. All measurements were carried out in a constant temperature room at 30 ° C. The results are also shown in Table 1.

<Materials Used> CaO Raw Material: Commercial Quicklime Al ₂ O ₃ Raw Material: High Purity Alumina Produced by Bayer Method, Commercial Product, Al ₂ O ₃ Purity 99% by Weight, Average Particle Diameter 70 μ SiO ₂ Raw Material: Commercial Fused silica α-Al ₂ O ₃ : Commercial product, purity 99.9% by weight, average particle size 50μ Fire-resistant aggregate a: Sintered alumina, commercial product Fire-resistant aggregate b: Fine alumina, commercial product Fire-resistant aggregate c: Silica fume, Commercial product Additive A: Reagent, sodium tripolyphosphate Additive B: Boric acid, commercial product Alumina cement α: Commercial product, main mineral composition CA 60% by weight,
CA ₂ 15% by weight, α-Al ₂ O ₃ 25% by weight Alumina cement β: Commercial product, main mineral composition 65% by weight, CA
₂ 30% by weight, α-Al ₂ O ₃ 5% by weight

<Measurement method> Mineral composition: Mineral composition amount quantified by the Zevine method using an X-ray diffractometer Flow value: Evaluation of fluidity, leaving the kneaded product in a thermostatic chamber at 30 ° C for a predetermined time, and tapping 15 times Measured pot life: Time required to transfer the kneaded product to a nylon bag in a thermostatic chamber at 30 ° C and cure with a finger. Curing time: Leave the kneaded product in a thermostatic chamber at 30 ° C using a temperature recorder. Time from pouring water to the time when heat generation temperature reaches maximum Curing strength: Room temperature strength Compressed strength after curing for 24 hours in a thermostatic chamber at 30 ° C after putting the kneaded product in a 4 × 4 × 16 cm formwork Dry strength: Room temperature strength, after curing for 24 hours, further 110 ℃
Compressive strength after drying for 24 hours at calcination strength: high temperature strength, after drying at 110 ℃, put in a siliconit electric furnace, calcining at 1,000 ℃ for 2 hours, and then allowing to cool to room temperature

[0068]

[Table 1]

As shown in Table 1, the amorphous refractory material of the present invention has better fluidity, longer pot life, and less curing time and compressive strength than those obtained by blending conventional commercial alumina cement. There was no problem.

Example 2 An example except that an alumina cement material having a mineral composition of 70% by weight of CA, 15% by weight of CA _{2 and} 15% by weight of C ₂ AS and α-Al ₂ O ₃ were compounded as shown in Table 2. The same procedure as 1 was performed. The results are also shown in Table 2.

[0071]

[Table 2]

Example 3 Refractory aggregate d40% by weight as aggregate (aggregate) of 5 to 3 mm, 3
Fire-resistant aggregate d45% by weight, 1 mm, as aggregate (aggregate) of 1 mm
Refractory aggregate d10% by weight and 200 as lower aggregate (aggregate)
As the aggregate (aggregate) under the mesh, 5% by weight of the refractory aggregate e was blended to obtain a refractory aggregate. This refractory aggregate and mineral composition
A mixture of 75% by weight of an alumina cement substance of 60% by weight of CA, 20% by weight of CA _{2 and} 20% by weight of C ₂ AS and 25% by weight of α-Al ₂ O _{3 of} alumina cement was added in a ratio shown in Table 3, and then the Chiyoda Giken An omni-mixer manufactured by Kogyo Co., Ltd. was used to mix for 20 minutes to produce the amorphous refractory material of the present invention. The same procedure as in Example 1 was carried out except that 10 parts by weight of water was added to 100 parts by weight of this amorphous refractory and the mixture was kneaded in a thermostatic mixer in a thermostatic chamber at 30 ° C. The results are also shown in Table 3.

<Materials used> Refractory aggregate d: fused alumina, commercial product Fire resistant aggregate e: calcined alumina, commercial product

[0074]

[Table 3]

As shown in Table 3, the amorphous refractory material of the present invention has better fluidity, longer pot life, and less curing time and compressive strength than those obtained by blending conventional commercial alumina cement. There was no problem.

Example 4 As Example 3 except that the alumina cement was 10 parts by weight, the refractory aggregate was 90 parts by weight, and the types of aggregates, aggregates, aggregates, and aggregates shown in Table 4 were used. I went the same way. The results are also shown in Table 4.

<Materials used> Fire-resistant aggregate f: Sintered magnesia spinel, commercially available product Fire-resistant aggregate g: Sintered magnesia, commercially available product

[0078]

[Table 4]

Example 5 100 parts by weight of an amorphous refractory material consisting of 10 parts by weight of alumina cement and 90 parts by weight of refractory aggregate, except that 0.05 parts by weight of an additive of the type shown in Table 5 was blended The same procedure as in Example 3 was performed. Table 5 shows the results.

<Materials used> Additive C: sodium polyacrylate, commercially available product Additive D: sodium citrate, commercially available product

[0081]

[Table 5]

Example 6 Alumina cement substances and α-Al ₂ O ₃ were blended, and the grinding time was changed by a batch type ball mill to prepare alumina cements having different Blaine values as shown in Table 6. Example 3 was repeated except that 10 parts by weight of the prepared alumina cement and 90 parts by weight of the refractory aggregate were mixed. The results are also shown in Table 6.

[0083]

[Table 6]

As shown in Table 6, the alumina cement of the present invention shows a tendency that as the Blaine value increases, the pot life and curing time tend to shorten, but the compressive strength tends to increase, and the Blaine value during pulverization tends to increase. By controlling
It is possible to control characteristics such as pot life.

Example 7 The amount of high-pressure air was used when clinker was manufactured in an electric furnace by blending various raw materials so that the mineral composition was 60% by weight of CA, 20% by weight of CA _{2 and} 20% by weight of C ₂ AS. By changing the vitrification rate of the melt to produce alumina cement materials with different vitrification rates. The same procedure as in Example 1 was performed except that 75 parts by weight of the produced alumina cement material and 25 parts by weight of α-Al ₂ O ₃ were crushed by a batch type ball mill to adjust the Blaine value to 4,900 cm ² / g. . The results are also shown in Table 7.

[0086]

[Table 7]

As shown in Table 7, the alumina cement of the present invention tends to have a longer pot life and a shorter curing time as the vitrification rate increases. In the present invention, it is possible to control characteristics such as pot life by controlling the vitrification rate of the alumina cement material.

[0088]

EFFECT OF THE INVENTION The alumina cement of the present invention and the amorphous refractory material using the same are capable of ensuring high fluidity and pot life, which are not available in conventional products, and have no problem in curability and strength development. It was a thing. When the product of the present invention is used in the refractory field, it can be applied to labor-saving construction methods such as pump construction and vibration-free construction, and prevents the occurrence of hardening trabs in the kneaded product during construction found in conventional products. it can. It can also be used as a lining material for a chemical plant or as a civil engineering and construction material that places importance on fluidity and pot life. Further, it can be widely applied to hydraulic ceramics, catalyst materials, corrosion resistant materials and the like.

Claims (4)

[Claims] 1. A _{CaO · Al 2 O 3, CaO} · 2Al 2 O 3, and 2CaO · Al ₂ O
Alumina cement containing α-Al ₂ O ₃ and an alumina cement substance containing a mineral composition of ₃ · SiO ₂ . Wherein the ratio of the mineral composition of alumina cement material, CaO · Al ₂ O ₃ 20~80 _{wt%, CaO · 2Al 2 O 3} 5~50 wt%, and _{2CaO · Al 2 O 3 · SiO} 2 5 Alumina cement according to claim 1, characterized in that it is -60% by weight. 3. 50 to 90 parts by weight of alumina cement material and α
According to claim 1 or 2, wherein alumina cement characterized by containing a -al ₂ O ₃ 10 to 50 parts by weight. 4. An amorphous refractory material containing the alumina cement according to claim 1 and a refractory aggregate.