JP3348815B2 - Alumina cement substance, alumina cement containing the same, and amorphous refractory using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alumina cement material, an alumina cement containing the same, and an amorphous refractory using the same, and in particular, has high fire resistance, high fluidity, and non-conventional products. The present invention relates to an alumina cement material for ensuring a pot life, an alumina cement containing the same, and an amorphous refractory using the same.

[0002] The alumina cement substance of the present invention, the alumina cement containing the same, and the amorphous refractory using the same are used in the field of refractories using alumina cement, lining of chemical plants, corrosion-resistant materials, catalysts. material,
And it can be used in the field of civil engineering and construction.

[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 Hydraulic cement produced by crushing the clinker alone or hydraulic cement crushed by adding alumina and various additives to the clinker Author, Cement Material Chemistry, pp.215-218, 1991, Refractories, Vol.29, p368-374,197
7, Refractory, Vol. 34, p634-640, 1982, Refractory, Vol. 35, p19
0-199,1983, and Trans.J.Br.Ceram.Soc., Vol. 81 (2), 1
982). In addition, the Japanese Industrial Standard (JIS) has a standard for alumina cement for refractories.
(CaO, Al ₂ O _3, and Fe ₂ O _3), fineness, I setting time, and by strength, alumina cement is defined to one 5 or. These alumina cements have been studied for a long time, mainly in Europe, and they are commonly used for the production of alumina cement, the characteristics of various mineral compositions, the method of adjusting the setting with various additives, and the adaptation to amorphous refractories. (TDRobson, High Alumina Cements
and Concrete, p1-45,1962 and refractories, Vol.34, p499-50
3,1982).

Conventionally, regarding high fire resistance, Al_TwoO_Three/ CaO molar ratio
Is added to alumina cement having a mineral composition of 0.6 to 1.2.
Manufacturing method of alumina cement mixed with mineral fine powder
No. 47-40694), CaO.Al_TwoO_ThreeClinker and certain
Fire resistance mixed with alumina having specific surface area and particle shape
Calcium aluminate cement (Japanese Patent Laid-Open No. 52-111920)
Report) and a specific proportion of CaO_TwoO_Three, 12CaO ・ 7Al_TwoO_Three,
Hydroxyamorphous alumina cement
Aluminum blended with additives such as rubonate and inorganic carbonate
Na cement composition (JP-A-55-45507) and the like have been proposed.
Was. And silicofluoride, polyacrylic acids, boric acid
Pot life and various additives such as carbonates
Improving the fluidity (JP-A-60-548497,
JP-A-55-759448, JP-A-61-86454,
(Kaihei 1-83543 and JP-A-6-32639).
CaO ・ Al_TwoO_ThreeAnd 2CaO ・ Al_TwoO_Three・ SiO_TwoAlumina seme consisting of
Coating retarder, CaO / Al_TwoO_ThreeAnd CaO ・ 2Al_TwoO_ThreeComposition
Α-Al for the linker_TwoO _ThreeAlumina which is blended with an additive
Cement compositions (JP-A-63-103847 and JP-A-7-23)
No. 2941) has been proposed. However, these
Lumina cement and alumina cement composition have high fire resistance,
It can be used as an irregular refractory, such as pot life, fluidity, and curability.
It did not satisfy all the required characteristics.

Furthermore, when these conventional alumina cements are used for 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 with a changed particle size distribution and alumina cement with a square or flaky particle shape have been proposed (Japanese Patent Application Laid-Open No. Sho 5).
JP-A-8-36953 and JP-A-61-7200). However, even if the particle size distribution and the particle shape of the alumina cement are changed, the elution control of polyvalent ions caused by calcium aluminate is insufficient, and the securing of fluidity and pot life is not satisfactory.

Conventionally, in order to ensure the fluidity and pot life of alumina cement, CaO · Al ₂ O ₃ of a specific ratio and CaO · 2Al ₂ O ₃
Alumina cement having a mineral composition of and combined with an additive has been proposed (JP-A-2-175538, JP-A-7-232941).
And JP-A-7-232956). However, despite the fact that this alumina cement is required to harden within a certain period of time, its mineral composition is CaO
Because it contains the ₂ O ₃ and CaO · 2Al ₂ O _3, construction temperature if low temperature, cause significant cure delay, there is a problem that it is difficult to cure within a predetermined period of time.

Further, there has been proposed an irregular-shaped refractory which can be constructed without vibration (self-leveling) using alumina cement and an aggregate having a specific particle size (JP-A-4-260673, JP-A-5-180689). Gazette, and JP-A-7-237977). However, there has been a problem that the fluidity of the amorphous refractory cannot be improved by using the particle size composition of the aggregate and the additive in combination.

[0008] Alumina cement described in these patents and literature may not be secured pot life is to be obtained the strength development, in order to obtain a high fire resistance, Al ₂ O ₃
When the content is increased, there are problems such as a decrease in fluidity and a lack of strength development, and it has not been possible to surpass the conventional quality level.

On the other hand, in the refractory field, which is a main use of alumina cement, the application range of amorphous refractories containing alumina cement tends to increase, and the construction method of amorphous refractories is also being reduced. Yes, for example, mass kneading, pumping, self-leveling, non-vibrator, and the like, which are performed when the amount of one operation exceeds 10 tons, have become widespread. for that reason,
In particular, for the purpose of high strength development and high density, alumina cement, ultrafine powder such as silica fume, and irregular shaped refractory blended with a dispersant, as the application range increases,
The problem of insufficient pot life has become more serious.

When alumina cement is mixed with water, Ca ²⁺ , Al ³⁺ , Mg ²⁺ , Na ⁺ , K ⁺ , and Al ₂ O ₄ are formed from the hydraulic calcium aluminate constituting the alumina cement.
^{2- and} other ions elute. The hydration reaction of alumina cement is a competitive reaction between a liquid phase reaction in which ions eluted from the alumina cement particles precipitate and the hardening is promoted, and a solid-liquid reaction in which hydration proceeds from the alumina cement particle surface layer, It was strongly influenced by the ambient temperature and various additives. Applying the theory of coagulation and hardening of the eluted ions and ultrafine powder, various technical reports have been made on the agglomeration and ensuring the pot life of amorphous refractories, especially those containing ultrafine powder. (Refractory, 33-59, p3 ~
7,1981, refractories, 33-393, p31-34,1981, and refractories, 40-
5, p270-278,1988).

Since the hydration of alumina cement proceeds by ions eluted into the liquid phase after water injection, based on the DLVO theory modeled on the agglomeration and dispersion of colloids, amorphous refractories aggregate the amount of eluted ions There is a problem that the speed is dependent and it is difficult to secure fluidity and usable life in a high-temperature construction atmosphere. The DLVO theory here refers to the theory of colloidal stability (Verwey, EJWetc., Thero
ry of the Stability of Lyophobic Colloids, Elsevie
(r, New york, 1948), based on the fact that the rheological properties of the suspension are closely related to the dispersion and agglomeration of the ultrafine powder. 1 shows the relationship between the electrostatic repulsion potentials of the above. According to this theory, the higher the concentration of the electrolyte and the higher the ionic value, the more the aggregation is promoted. Ca ²⁺ eluted from alumina cement
Polyvalent ions such as Al ₂ O ₄ ^{2− and the} like impart coagulation properties to the amorphous refractory, and the coagulation is accelerated, resulting in a decrease in fluidity and a reduction in the pot life. For this reason, in the conventional alumina cement, there was a problem that the control of polyvalent ions was insufficient and it was not possible to ensure fluidity and usable life.

In particular, in construction by pumping for the purpose of labor saving, construction by a concrete mixer truck, non-vibrator construction, and the like, fluidity when made into an irregular refractory is very important. With conventional alumina cement, there were problems that fluidity and pot life could not be ensured, and that the cement was hardened in the mixer and could not be discharged from the hopper.

Further, in recent years, characteristics as an amorphous refractory adapted to various construction methods have been required, and there has been a problem that conventional alumina cement cannot ensure sufficient fluidity and pot life.

[0014] On the other hand, the alumina cement containing CaO · 2Al ₂ O _3, hardening delay at low temperatures construction since the hydration activity of CaO · 2Al ₂ O ₃ is less tended to occur. In addition, 12CaO
Alumina cement containing 7Al ₂ O ₃ has a tendency to accelerate ionization because of rapid elution of ions and tends to be unable to ensure the pot life and fluidity. These CaO.2Al ₂ O ₃ and 12CaO.7Al ₂
As curing control agent of calcium aluminate such as O _3,
The above-mentioned additives are used, but if the additive amount is increased to secure the pot life, or if an additive with a more delayed action is added, the curing delay will increase, and problems such as not curing depending on the application temperature will occur. Therefore, in the conventional technology, there is a limit in securing the pot life and fluidity of the amorphous refractory, and there is a problem that high refractory cannot be obtained.

When alumina cement is used in the field of refractories, those containing SiO ₂ have inferior fire resistance.
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
And remained on the extent of the _second amount, the _{2CaO · Al 2 O 3 · SiO} 2 is
Since the hydration activity is remarkably low and the fire resistance is lowered, there has been no active use of alumina cement so far.

Furthermore, SiO derived from raw material impurities_Two, Ti
O_Two, Fe_TwoO_ThreeAnd chemical components such as MgO are used for irregular refractories.
When used, a low-melting compound is formed, and the fire resistance and hot strength are reduced.
There was a problem that it decreased. However, 2CaO.A
l_TwoO_Three・ SiO_TwoWhen used for irregular shaped refractories,
Shows excellent properties such as longer coagulation time in the early stage of water
However, 2CaO ・ Al_TwoO_Three・ SiO _TwoSiO due to the presence of_TwoIncrease in content
Addition causes significant curing delay and strength reduction, and
Lowering of refractory and hot bending by forming liquid phase under
Reduces strength and limits its use as a refractory
There was a problem that.

Further, the mineral composition of the conventional alumina cement has been limited to those mainly composed of CaO.Al ₂ O ₃ in terms of securing appropriate fluidity and imparting strength and hardening property.
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 reduced, high fire resistance and curing retardation are exhibited.

On the other hand, in order to adjust the curing rate of calcium aluminate, it has been proposed to incorporate a fast-setting calcium aluminate such as 12CaO.7Al ₂ O ₃ (Japanese Patent Application Laid-Open No.
-13639). In addition, CaO · 2Al ₂ O ₃ and 3CaO · 5Al ₂ O ₃ is,
There is a problem that a large retarders of those having a high fire resistance, as those are balanced fluidity, curability, and the strength _{development, CaO · Al 2 O 3,} CaO · 2Al 2 O 3, and 12CaO · 7
Alumina cement mixed with Al ₂ O ₃ has been proposed (JP-A-7-61844). In addition, as a material that provides retardation to alumina cement, Ca having a specific vitrification rate
O · Al ₂ O ₃ and _{2CaO · Al 2 O 3 · SiO} 2 and retarder composed mainly of has been proposed (JP 61-248487 JP). However, even if this curing retarder is used, there is a problem that the curing time and the high fire resistance cannot be sufficiently ensured, and the extension of the pot life is also insufficient.

As a technique in which an additive is used in combination for the purpose of ensuring fluidity and pot life, for example, a specific proportion of CaO.Al
₂ O ₃ , 12CaO ・ 7Al ₂ O ₃ , and amorphous, α-Al ₂ O ₃ ,
Hydroxycarboxylic acid, and an alumina cement composition containing an inorganic carbonate (Japanese Patent Publication No. 45-129562,
JP-A-49-32921, JP-A-50-102617 and JP-A-55-121933), water-soluble polyacrylic acids and / or methacrylic acid-acrylic acid copolymers and alkali metals Alumina cement containing carbonate
(Such as JP-A-55-75947 and JP-A-55-75948), an alumina-containing alumina cement having a specific CaO / Al ₂ O ₃ molar ratio, or CaO.Al ₂ O ₃ , CaO ・ 2Al ₂ O ₃ , 3Ca
_{O · Al 2 O 3, 12CaO} · 7Al 2 O 3, and 11CaO · 7Al ₂ O ₃ · Alumina cement mainly composed of amorphous calcium aluminate corresponding to one or more mineral composition of CaF ₂ and the like ( JP 61
-132556, JP-A-61-77659, and JP-A-Hei2
Publication No. -175638), at least 80% by weight or more of CaO
Alumina cement containing Al ₂ O ₃ clinker and alumina having a specific specific surface area, or alumina cement containing alumina fine powder in alumina cement clinker (Japanese Patent Application Laid-Open No. 52-111920 and Japanese Patent Publication No. 43-43). 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 proportion of CaO.Al ₂ O ₃ and CaO
Alumina cement comprising clinker containing 2Al ₂ O ₃ and α-Al ₂ O ₃ (USP 4162923), calcium aluminate, polyacrylic acid, boric acid, and cement composition comprising carbonate or carboxylic acid No. 6-157097) was proposed, but when applied to low cement castables, there was a problem that the pot life could not be secured at the time of high-temperature construction or the like, and sufficient fluidity could not be secured.

Normally, all commercially available alumina cements are mainly composed of CaO.Al ₂ O ₃ , and 12CaO.7Al
_It contained ₂ O ₃ , α-Al ₂ O ₃ , additives and the like, and contained a small amount of CaO · 2Al ₂ O ₃ as a by-product during clinker production.

Al using natural materials such as bauxite
Mina cement has 2CaO ・ Al_TwoO_Three・ SiO _TwoWhat can be seen
However, it is the amount as an impurity to the last, as in the present invention.
Did not actively adjust the composition as a mineral composition
(Refractory, Vol.29, p368-374,1977, Refractory, Vol.34, p634
640, 1982). In addition, high-purity alumina or aluminum hydroxide
In alumina cement using synthetic raw materials such as
SiO_TwoContains a problem that the fire resistance is reduced,_TwoIs
It is positively excluded and various mineral compositions as in the present invention
Combined with SiO_Two2CaO.Al containing_TwoO_Three・ SiO_Two
Nothing elicited the properties of the mineral composition. And this
In these alumina cements, the refractory sector,
Irregular fire resistance required in the steel field such as facilities and steelmaking facilities
The property levels of the material include fluidity, strength development, fire resistance,
There is a problem that the corrosion resistance and corrosion resistance are insufficient.

On the other hand, as the 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), p35
42, 1982, and refractories, No. 11, p 18 to 24, 1982). However, there has been a problem that when used for actual amorphous refractories, sufficient fluidity and pot life cannot be secured.

Further, in order to improve the long-term strength of the alumina cement, a technique for mixing the steel slag powder containing _{2CaO · Al 2 O 3 · SiO} 2 has been proposed (JP 53-12926 and JP JP-A-60-5055). However, when used for irregular-shaped refractories, there are problems that not only the fluidity and the pot life cannot be sufficiently ensured, but also the fire resistance is insufficient and the strength at high temperatures is insufficient.

The present inventor has conducted various studies to solve the above problems, and as a result, obtained the finding that the above problems can be solved by using an alumina cement material or alumina cement having a specific mineral composition. It was completed.

[0025]

Means for Solving the Problems That is, the present invention is the mineral composition _{CaO · Al 2 O 3, CaO} · 2Al 2 O 3, and 2CaO · Al ₂ O ₃ · Si
O ₂ , the chemical composition of which is CaO 10 to 35 % by weight, and Al ₂ O ₃ 64 to 8
5 % by weight, and 0.6-10% by weight of SiO ₂ , the impurity TiO
_{2. An} alumina cement material having a total amount of ₂ , ₂ or less of Fe ₂ O ₃ and MgO of 5.2 % by weight or less, and an alumina cement containing α-Al ₂ O ₃ and the alumina cement material. And a refractory aggregate.

Hereinafter, the present invention will be described in detail.

The alumina cement substance used in the present invention is such that, when CaO is C, Al ₂ O ₃ is A, and SiO ₂ is S, the mineral composition is CA, CA ₂ , and C ₂ AS, and the chemical component is CaO10～ 35 _{wt%, Al 2 O 3 64 ~} 85 wt%, and SiO ₂ 0.6 to 10 wt%
And the total amount of impurities TiO ₂ , Fe ₂ O ₃ , and MgO is
It is an alumina cement material that is less than 5.2 % by weight, and the content of this particular mineral composition is important. In other words, in the prior art, the unfavorable C ₂ AS, which is a component of the alumina cement and causes undesired hardening delay, decrease in strength development, and decrease in fire resistance, is reduced to a specific proportion of CA and CA _2.
By using in combination, fluidity can be ensured and the pot life can be prolonged without causing significant delay in curing or reduction in strength development.

Alumina cement materials include CaO raw materials such as limestone and quick lime, natural raw materials such as bauxite and red bauxite, high-purity alumina obtained by purifying these natural raw materials by a purification method such as the Bayer process, and aluminum residual ash. Al ₂ O ₃ raw material, etc., and silica sand, fused silica, clay, rubble, and SiO ₂ raw material such as chamotte are blended so that the mineral composition in the heat-treated product becomes a predetermined ratio, an electric furnace, Clinker obtained by melting and / or firing is crushed in equipment such as a reverberatory furnace, a vertical furnace, a flat furnace, a shaft kiln, and a rotary kiln.

The firing method is described in Journal of the Ceramic Industry Association, Vol. 83 (5), p.
~ 243,1975, CaO raw material, Al ₂ O ₃ raw material,
Since the formation reaction of calcium aluminate and the raw material of SiO ₂ proceeds by a solid phase diffusion reaction, a multiphase mineral composition is easily formed in the clinker, and the mineral composition intended in the present invention tends to be hardly obtained. Therefore, in the present invention, it is preferable to produce clinker by a melting method in which the mineral composition ratio of calcium aluminate is easily produced within the object of the present invention as compared with clinker produced by a firing method. In the melting method,
Since the formation reaction of calcium aluminate proceeds thermodynamically, the desired mineral composition of the present invention can be obtained relatively easily. When producing an alumina cement material by a melting method, a CaO raw material, an Al ₂ O ₃ raw material, and a SiO ₂ raw material are mixed and / or mixed and pulverized at a predetermined ratio, and are then melted in a melting furnace such as an electric furnace, a flat furnace, or a reflection furnace. It is preferable to melt at a high temperature of 1,500 ° C. or more, and it is more preferable to melt until the unreacted raw materials are completely eliminated. It is preferable that after the raw material mixture is melted, the raw material mixture is contacted with high-pressure air or water and cooled to obtain alumina cement clinker. In the pulverization and mixing of these clinkers, the clinkers may be mixed and then pulverized, or each pulverized mixture may be mixed. In particular, means for achieving the desired mineral composition ratio is limited. Not something. As a clinker pulverizer, a pulverizer, 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 a lump of powder can be used.

The method for obtaining the mineral composition of interest in the present invention includes a method of synthesizing the CA-CA ₂ -C ₂ AS mineral composition at a time,
A method of independently synthesizing each mineral composition of A, CA ₂ , and C ₂ AS and blending them in a predetermined ratio, and a CA-CA ₂ mineral composition, CA ₂ -C ₂ AS mineral composition, CA, CA _2, and to synthesize a clinker containing C ₂ aS mineral composition, and a method of mixing so as to have a predetermined mineral composition.

In the present invention, the mixing ratio of the mineral composition is Cu
It can be analyzed by X-ray diffraction analysis using -Kα ray. As a method of quantifying the mineral composition by the X-ray diffraction method, there are a diffraction ratio intensity ratio measuring method, an internal standard method, a Zevine method, an X-ray diffraction peak separation method, and the like. is there. The method of measuring the intensity ratio of the diffraction line referred to here is a value that relatively represents the diffraction intensity of each mineral composition, and 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 in which a calibration curve is prepared and analyzed using a standard sample having a known concentration by 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 of measuring the average mass absorption coefficient of a sample and the diffraction line intensity ratio and quantifying each crystal phase by solving an n-order simultaneous equation. Alternatively, it can be calculated by quantifying the components of the sample by chemical analysis. In addition, it can be quantified by an X-ray diffraction peak separation method measured from the crystal or glass phase of the sample. In the present invention, the mineral composition and the vitrification ratio can be quantified by any of the methods, but the Zevine method or the diffraction line intensity ratio measuring method, which is simple and accurate, is preferable.

The mineral composition ratio of the alumina cement material is as follows:
CA 20-80 parts by weight, CA_Two5 to 50 parts by weight, and C_TwoAS5-60
Parts by weight are preferred, CA 40 to 60 parts by weight, CA_Two10-30 parts by weight,
And C _TwoAS 10 to 30 parts by weight is more preferred. Alumina cement
If the mineral composition ratio of the mineral substance is out of this range, the fluidity and hardness
In some cases, the curability and the strength development may deteriorate. In particular, CA
_TwoIs small, the amount of aluminum hydroxide produced after hydration is small.
No, when used for irregular refractories, about 800-1,000 ℃
The strength in the inter-temperature range may decrease, and a certain amount of CA
If it is not contained, the strength developability is insufficient. Also, C_Two
When the content of AS is large, the strength decreases and the curing delay is large. this
Because of CA, CA_Two, And C_TwoThe mineral composition of AS is important
You.

In the present invention, the chemical composition of the alumina cement material is important, and CaO is 10 to 35 % by weight and Al ₂ O ₃
64-85% by weight, and SiO ₂ 0.6 to 10 wt%. When the content of Ca O is less than 10% by weight,
If the strength developability is insufficient and the amount of Al ₂ O ₃ is small, the fire resistance may decrease. Further, when the content of SiO ₂ is large, the fluidity is improved and the pot life is prolonged, but the curing retardation and the strength development may be remarkably reduced. The alumina cement material of the present invention includes, in addition to target CA, CA ₂ and C ₂ AS,
It is also possible to use those containing impurities such as α-Al ₂ O ₃ due to the raw material and CaO · TiO ₂ or 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ generated from the impurities in the raw material, It is preferable that the impurities in the alumina cement material are small, and the total amount is 5.
2 % by weight or less, TiO ₂ 0.5% by weight or less, Fe ₂ O ₃
0.5 wt% or less and MgO 0.5 wt% or less are more preferable. When these impurities increase, not only the fire resistance, but also the properties such as strength development, volume stability as a cured product under high temperature and spalling resistance are deteriorated, and the corrosion resistance to slag and the like is reduced. There are cases.

The vitrification rate of the alumina cement material in the present invention can be adjusted by the cooling rate of the molten and / or calcined high-temperature clinker, and is not particularly limited. A high rate is preferable because the pot life can be extended. The vitrification ratio can be measured by analyzing the mineral composition by the powder X-ray diffraction method, and the vitrification ratio increases as the intensity of the diffraction line decreases. In the present invention, the vitrification rate is preferably 20% or more,
50% or more is more preferable. This vitrification ratio can be measured by disappearance of the diffraction line by the powder X-ray diffraction method, and is calculated by the formula of vitrification ratio (% by weight) = 100− (peak area / total diffraction line area) × 100. it can. Alumina cement is generally produced by a method in which clinker produced by melting or sintering is brought into contact with water or air to cool it.However, if quenched at the time of cooling, the vitrification rate increases, and SiO ₂ in the clinker mineral composition increases. The higher the content, the higher the vitrification rate.

Since the particle size of the alumina cement material or alumina cement affects fluidity, hardening property, and strength development, it is an important control point for obtaining desired properties. For example, JIS R 2521
Can be measured by the method for measuring the specific surface area of the brane described in 2,000 to 8,000 cm ² / g, preferably 4,000 to 7,000 cm ²
/ g is more preferred. If it is less than 2,000 cm ² / g, the hydration activity as an alumina cement substance or alumina cement is low, and the strength developability tends to decrease and poor curing tends to occur. On the other hand, if it exceeds 8,000 cm ² / g, the hydration activity becomes too large, and the pot life after water injection tends to be insufficient. 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 20 μm, the fluidity tends to decrease and curing tends to be delayed. Here, the average particle diameter is a value of a particle size measurement result by a generally used particle size distribution measuring device such as a laser diffraction method, a laser scattering method, and a sedimentation balance method, and is a 50% average diameter. .

The alumina cement material of the present invention can be used as it is as an alumina cement.
When the alumina cement of the present invention is used for an amorphous refractory, it is preferable to mix α-Al ₂ O ₃ from the viewpoint of imparting high fire resistance, high-temperature strength development, corrosion resistance and volume stability. In addition, the characteristics of alumina cement vary greatly depending on the type of α-Al ₂ O ₃ to be blended. Therefore, selection of α-Al ₂ O ₃ is important.

[0037] The α-Al ₂ O _3, a purified alumina obtained by calcining a highly purified treated aluminum hydroxide by the buyer processes like in the rotary kiln, Al ₂ O
High-purity alumina containing 90% by weight or more of ₃ and is generally called high-purity alumina, Bayer alumina, easily sintered alumina, or lightly burned alumina. In particular,
In the present invention, the properties which cannot be exhibited in conventional products can be exhibited for the first time by the interaction with the alumina cement material to be combined.

As for the particle size of α-Al ₂ O ₃ , the primary particle size before pulverization is preferably an average particle size (Dp50) of 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 firing degree of α-Al ₂ O ₃ is preferably 0.2 to 100 m ² / g in terms of specific surface area by BET method. The degree of firing indicates that the larger the specific surface area, the lighter the firing type of alumina,
When used at a high temperature, the sinterability is excellent, but the shrinkage tends to be large. When the specific surface area is large, the fluidity of the alumina cement decreases, and when it is small, the fluidity tends to be improved. If the specific surface area is large, the sinterability at a high temperature is improved when blended with an amorphous refractory, but the oversintering tends to reduce the spalling resistance and increase the shrinkage. Those containing alumina having a small specific surface area show the opposite tendency. Therefore, α used in the present invention
-The choice of Al ₂ O ₃ should be carefully selected because it greatly affects the properties of alumina cement, and should be determined as appropriate according to the required quality when blended with amorphous refractories. In the invention, the primary particle diameter of α-Al ₂ O ₃ is 30 to 100 μm.
Preferably, the firing degree of alumina is 0.2 to 100 m ² / g, the primary particle diameter is 40 to 80 μm, more preferably 0.3 to 10 m ² / g, and the fluidity, curability, strength development, shrinkage, and From the viewpoint of poling properties, the primary particle size is 45 to 65 μ, and the degree of baking is 0.5 to
Most preferred is 2 m ² / g.

Further, the purity of the α-Al ₂ O _3, if alumina is prepared by conventional buyer process, Al ₂ O ₃ 9
Purity of 8% by weight or more can be secured. In the present invention, A
l ₂ O ₃ purity has never been high, but 98% by weight
The above is sufficient. 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 Tend to decrease or shrink at high temperatures. Therefore, the amount of Na ₂ O is preferably small, preferably 0.5% by weight or less, more preferably 0.35% by weight or less.

In the present invention, this α-Al ₂ O ₃ and clinker of alumina cement are blended and mixed and pulverized with a pulverizer, or α-Al ₂ O ₃ alone is pulverized to a particle size equivalent to alumina cement. It is also possible to mix with the clinker ground. When pulverizing α-Al ₂ O ₃ alone, it is preferable to pulverize Dp50 to about 1 to 10 μm. In particular, in the present invention, α
-When Al ₂ O ₃ is mixed and crushed with clinker, it is more compatible with alumina cement particles, and it is uniformly mixed in alumina cement, so when used for irregular refractories, the hardened body structure becomes uniform , The corrosion resistance tends to be improved.

The amount of the α-Al ₂ O ₃ is alumina cement in 100 parts by weight of alumina cement material and α-Al ₂ O _3, preferably 0 to 50 parts by weight, more preferably 10 to 40 parts by weight, Most preferred is 20 to 40 parts by weight. Increasing the amount of α-Al ₂ O ₃ increases fire resistance and sintering strength at high temperatures, but also decreases curing strength and dry strength at room temperature, and tends to decrease fluidity. Although the chemical composition after α-Al ₂ O ₃ blending is
O21~28 wt%, Al ₂ O ₃ 70-78% by weight, and SiO _2. 1 to
Those blended so as to be 4% by weight are more preferable in terms of good fluidity and high strength development. CaO
And SiO ₂ is large, the corrosion resistance and refractoriness tends to be remarkably lowered. In the case of amorphous refractories containing magnesia aggregate as refractory aggregate, if there is a large amount of α-Al ₂ O ₃ in alumina cement, it may react with magnesia at high temperature to form magnesia spinel, Due to the tendency of volume expansion in the process, it is necessary to mix a large amount of α-Al ₂ O ₃ in alumina cement so as to exceed 80% by weight. And 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 and the amorphous refractory, it is usually blended with the amorphous refractory, for example, refractories, 33-59, p3-7, 1981,
Refractories, 3-393, p31-34, 1981, and refractories, 40-5, p270-2
Additives such as curing retarders and curing accelerators described in 78, 1988 and the like, and fluidizing agents and the like can be used in combination.

Examples of the curing retarder include carboxylic acids, alkali metal carbonates, boric acids, polyacrylic acids, polymethacrylic acids, and phosphoric acids, of which the use of carboxylic acids or alkali salts thereof is preferred. Here, carboxylic acids are oxycarboxylic acids,
Specific examples include citric acid, gluconic acid, tartaric acid, succinic acid, lactic acid, malic acid, and salicylic acid, or alkali salts thereof such as sodium, potassium, and calcium salts. 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 carboxylic acids that are industrially purified can be used at present, and the purity of the target carboxylic acid is preferably about 80% by weight or more. Among them, citric acid or a salt thereof containing 0.05% by weight or less of sulfate as an impurity, and a 1% by weight aqueous solution at 20 ° C having a pH of 7 to 7%.
It is preferable to use 10 citric acid or a salt thereof because the pot life is excellent.

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

The boric acids refer to boric acid or an alkali salt thereof. Boric acid is also called boric acid, orthoboric acid, or orthoboric acid, is denoted 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, the raw ore of boric acid is heated and decomposed by adding sulfuric acid to release and separate boric acid, followed by purification. 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 the 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 acid is not particularly limited, but boric acid that is industrially purified can be used at present, and the content of BO _{4 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. The use of sodium polyacrylate is most preferred because of its easiness and ease of handling.

The polymethacrylic acids are polymethacrylic acids or salts thereof, and include sodium polymethacrylate, polypotassium methacrylate, polyammonium methacrylate, etc. Among them, performance, price,
The use of sodium polymethacrylate is most preferred because of its availability and ease of handling.

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. Preferred from the strong side.

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 the amount is less than 0.5 part by weight, the workability may be reduced. If the amount is more than 2.5 parts by weight, curing may be delayed or the strength may be reduced.

The fluidizing agent is an admixture mainly composed of a surfactant having excellent cement dispersibility, and is generally a salt of a naphthalenesulfonic acid formalin condensate (a naphthalene type), a melamine resin sulfonic acid formalin condensate. (Melamine-based) and olefin / maleic acid copolymer salts
(Carboxylic acid type) and the like can be used. Specific examples include sodium salts of highly condensed β-naphthalenesulfonic acid, sodium salts of creosote oil sulfonic acid condensate, sodium salts of low-condensed β-naphthalenesulfonic acid, and polyoxyethylene nonylphenyl ether. . The use amount of the fluidizing agent is not particularly limited, but is preferably 0.5 to 5 parts by weight based on 100 parts by weight of the amorphous refractory made of alumina cement and refractory aggregate.

The method of blending the additives and the fluidizing agent is not particularly limited. The additives and the like are blended so as to have a predetermined ratio, and alumina cement which has been pulverized in advance and a V-type blender, a corn blender, a Nauta A mixer, a pan-type mixer, and a homogenizer using a mixer such as 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. Also, in the present invention, additives and the like 100 to 4
Heat at a temperature of 00 ° C and mix with alumina cement,
Alternatively, a method of heating a mixture of an additive and the like and alumina cement together is possible. As a heating method, a method of heating simultaneously with pulverization, a method of heating with hot air during transportation, a method of heating a transport machine, a method of heating during storage, and the like are possible.

These additives and the like include ICP, ICPA,
The type and quantitative ratio can be specified by instrumental analysis such as GC-MS, NMR, HPLC, and FT-IR, chelate analysis, and activation analysis.

[0054] Water used in the present invention is not limited in particular, tap water, natural water, and river water, etc., although the water used for general concrete can be used, Na ^+, K
The use of water with low soluble components such as ⁺ , Mg ²⁺ , Ca ²⁺ and Cl ⁻ is preferred. The amount of water used is appropriately determined depending on the intended amorphous refractory, and is not particularly limited,
If the amount is large, breathing or strength decreases. Therefore, in the case of the irregular-shaped refractory to be cast, it is usually preferable to use 2 to 20 parts by weight based on 100 parts by weight of the irregular-shaped 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 fire-resistant aggregate used in the present invention is a fire-resistant aggregate.
When used in a low cement castable type consisting of 92 to 99% by weight and 1 to 8% by weight of alumina cement, the effect is more pronounced, and refractory aggregates usually used for amorphous refractories can be used. . Specific examples include magnesia, magnesia spinel, alumina, carbon, and ultrafine powder.Others, fused silica, calcined mullite, chromium oxide, bauxite, andalusite, sillimanite, chamotte, silica stone, Raw stone, clay, zircon, zirconia, dolomite, perlite, vermiculite, brick waste, pottery waste, silicon nitride,
Boron nitride, silicon carbide, silicon iron nitride and the like can be used. In particular, in the amorphous refractory of the present invention, from the viewpoint of corrosion resistance, durability (durability), and fire resistance, magnesia aggregate, magnesia spinel aggregate, alumina aggregate,
It is preferable to mix one or more refractory aggregates selected from carbonaceous aggregates, ultrafine powder, and aggregates such as chamotte and silicon carbide. Also, when used in the steelmaking process of the steelmaking process, from the perspective of suppressing slag penetration,
A combination of magnesia aggregate and alumina aggregate, or a combination of magnesia spinel aggregate and alumina aggregate is preferable, and when used in the hot metal process, alumina aggregate such as fused alumina or sintered alumina and carbon are preferably used. Fine aggregate, ultra fine powder,
And the combination of additives and the like are preferable.

Here, the magnesia aggregate refers to magnesium hydroxide, magnesium carbonate, magnesite which is natural magnesia, or magnesite which is natural magnesia extracted from seawater by the seawater method, or sinter obtained by firing in a rotary kiln or the like. Magnesia clinker, or the fused magnesia clinker obtained by melting the sintered magnesia clinker in an electric furnace or the like, further pulverize a mixture of sintered magnesia clinker and fused magnesia clinker to a predetermined size, When sieved, MgO having a purity of 80% by weight or more is used for amorphous refractories, it is preferable in terms of excellent corrosion resistance, and one having few impurities such as SiO ₂ and TiO ₂ is 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. Specifically, molten magnesia, sintered magnesia, natural magnesia, and lightly burned magnesia can be used.
Magnesia with spinel coating, magnesia with magnesium titanate in the grain boundaries, magnesia with calcium aluminate generated on the magnesia particle surface, high purity, high bulk density, and coarse crystal grains used for basic bricks Special magnesia, and special magnesia obtained by pulverizing magnesia and zirconia with improved heat spalling properties can also be used. The MgO / Al ₂ O ₃ molar ratio in the magnesia clinker is 1/1 to 0.1 / 1.
And 0.4 / 1 to 0.2 / 1 are more preferable from the viewpoint of excellent durability when blended with the amorphous refractory.

Magnesia spinel aggregate is a mixture of a MgO raw material such as magnesium hydroxide or calcined magnesia and an Al ₂ O ₃ raw material such as aluminum hydroxide or calcined alumina in a predetermined ratio. Magnesia spinel clinker reacted and fired at a temperature of about 1,800 to 1,900 ° C. using a firing device such as a rotary kiln, and a magnesia spinel clinker melted by a melting device such as an electric furnace. A magnesia spinel clinker or the like obtained by mixing a calcined material and a molten material is crushed to a predetermined size and sieved. Specific examples include a molten magnesia spinel and a sintered magnesia spinel.

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. Crushed and sieved, and as a mineral composition, α-Al ₂ O ₃ or β
-Al ₂ O ₃ is an aluminum oxide that is referred to as sintered alumina, calcined alumina, easily sintered alumina, or the like. Usually α- containing 90% by weight or more of Al ₂ O ₃
The use of Al ₂ O ₃ is most preferred. Specific examples include fused alumina, sintered alumina, lightly fired alumina, easily sintered alumina, and the like. Further, it is also possible to use alumina / zirconia clinker obtained by melting alumina and zirconia clinker and having improved heat spalling resistance.

As the carbonaceous aggregate, oil pitch,
Tar and scale graphite.

The refractory aggregate is prepared by blending various particle sizes according to required physical properties. The particle size of the refractory aggregate is usually 5 to 3 mm.
4-1 mm, 3-1 mm, 1 mm below, 200 mesh below, and 325
It is divided under the mesh.

In the present invention, as the refractory aggregate, it is possible to use ultrafine powder having a fine particle diameter. Here, ultrafine powder means particles having a particle size of 10μ or less.
80% by weight or more of refractory fine powder having an average particle size of 1
A compound having a specific surface area of not more than μ and a specific surface area of not less than 10 m ² / g by the BET method is preferable because it can secure fluidity and exhibit high strength when mixed with an amorphous refractory. Specifically, inorganic fine powders such as silica fume, colloidal silica, light-burned alumina, easily sintered alumina, amorphous silica, zircon, silicon carbide, silicon nitride, chromium oxide, and titanium oxide can be used. Of these, use of silica fume, colloidal silica, and easily sintered alumina is preferred. In particular, silica fume used in low-cement castables is important because the pH of the slurry when forming a slurry affects the dispersibility, and a weakly acidic to acidic one is particularly preferred in terms of ensuring a usable life.

The amount of the refractory aggregate of the present invention should be appropriately determined depending on the construction site, and is not particularly limited, but is preferably 50 to 99 parts by weight based on 100 parts by weight of the amorphous refractory. From the viewpoint of corrosion resistance, 85 to 90 parts by weight is more preferable. In low-cement castables using ultrafine powder as refractory aggregate, the compounding of 2 to 6 parts by weight of alumina cement, 94 to 98 parts by weight of refractory aggregate, and 5 parts by weight or less of silica fume significantly increases fluidity and pot life. This is preferable from the viewpoint of ensuring that

The method for producing the amorphous refractory of the present invention is not particularly limited. However, according to the ordinary method for producing an amorphous refractory, the constituent materials are blended so as to have a predetermined ratio. Uniform mixing using a mixer such as a mold blender, cone blender, Nauta mixer, bread mixer, omni mixer, etc., or when kneading at a predetermined ratio, weighing directly into the kneader It is possible.

Further, the amorphous refractory of the present invention includes metal powders such as metal aluminum and silicon alloy, organic fibers such as vinyl fiber and polypropylene, for the purpose of preventing explosion which is likely to occur when the cured product is dried. It is also possible to add a nitrogen-containing gas product and an anti-explosion agent such as dextrin if necessary. The amount of the explosion-preventing agent to be used must be determined appropriately according to the intended explosion resistance and cannot be unambiguously determined.
It is possible to mix 0.05 to 5 parts by weight with respect to 100 parts by weight.

[0065]

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

Example 1 CaO raw material, Al_TwoO_ThreeRaw materials and SiO_TwoMix the raw materials and use in electric furnace
After melting, the melt is quenched by high-pressure cooling air.
A clinker with a constant mineral composition was synthesized. Synthetic clean
Adjust the brain value according to the grinding time to about 4,80
0cm^Two/ g with a batch-type ball mill.
Alumina cement material was produced. Manufactured aluminum
When the mineral composition of the nasement material was measured, CA, C
A_Two, And C _TwoAS has been identified. Similarly, chemical analysis
Specified. Table 1 shows the results. Impurity TiO_TwoAnd MgO is 0.1 weight
In% by mass, Fe_TwoO_ThreeWas 0.5% by weight. This alumina semester
3 parts by weight of alumina cement made of cement material, particle size 4 ~
1mm refractory aggregate a79 parts by weight, refractory aggregate b18 with a grain size 1mm
Parts by weight, 3 parts by weight of refractory aggregate c, which is
Formed refractories were manufactured. 100 weight of manufactured refractories
Parts by weight of additive A 0.05 parts by weight, additive B 0.03 parts by weight
Parts, and 7.6 parts by weight of water, and knead with a mixer for 5 minutes.
After, mineral composition, flow value as fluidity, pot life, hardening
Curing strength, dry strength, and high temperature strength as time and room temperature strength
The firing strength was measured as a degree. All measurements are at 30 ° C
Performed in a constant temperature room. 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 the Bayer method, commercial product, Al ₂ O ₃ purity purity 99% by weight, average particle diameter 70 μ SiO ₂ raw material: Commercial , Fused silica refractory aggregate a: sintered alumina, commercial product refractory aggregate b: fine powder alumina, commercial product refractory aggregate c: silica fume, commercial product Additive A: reagent, sodium tripolyphosphate Additive B: boric acid, Commercial goods

<Measurement method> Mineral composition: Mineral composition determined by the Zevine method using an X-ray diffractometer Chemical analysis: Measured according to JIS R 2522 Flow value: Evaluation of fluidity, kneaded material in a 30 ° C. constant temperature room After standing for a predetermined time, measure by tapping 15 times. Pot life: Time required to transfer the kneaded material into a nylon bag in a constant temperature room at 30 ° C and to cure with a touch finger Curing time: Using a temperature recorder , Time from water injection when the kneaded material is left in a 30 ° C constant temperature room to the maximum heat generation temperature Curing strength: room temperature strength, put the kneaded material in a 4 × 4 × 16cm formwork, and in a 30 ° C constant temperature room Compressive strength after curing for 24 hours Dry strength: Room temperature strength, 110 ° C after curing for 24 hours
Compressive strength after drying for 24 hours at 100 ° C Firing strength: High temperature strength, after drying at 110 ° C, placing in a siliconite electric furnace, firing at 1,000 ° C for 2 hours, and then cooling to room temperature

[0069]

[Table 1]

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

Example 2 The same procedure as in Example 1 was carried out except that an alumina cement material having a chemical composition shown in Table 2 was used. The results are also shown in Table 2. For comparison, the same procedure was performed using four types of commercially available alumina cement. The results are also shown in Table 2.

<Materials> Alumina cement α: Commercial product, main mineral composition CA 47% by weight,
C₁₂A₇3% by weight and α-Al_TwoO_Three50% by weight alumina cement β: Commercial product, 60% by weight of main mineral composition CA,
CA_Two15% by weight and α-Al _TwoO_Three25% by weight alumina cement γ: Commercial product, main mineral composition CA65% by weight,
CA_Two30% by weight and α-Al _TwoO_Three5% by weight alumina cement δ: Commercial product, 63% by weight of main mineral composition CA,
CA_Two31% by weight, and α-Al _TwoO_Three6% by weight

[0073]

[Table 2]

Example 3 As a 5 to 3 mm aggregate (aggregate), refractory aggregate d 40% by weight, 3
45% by weight of refractory aggregate as 1mm aggregate (aggregate) 1mm
As the lower aggregate (aggregate), refractory aggregate d 10% by weight, and 200
As the aggregate under the mesh (aggregate), 5% by weight of refractory aggregate e was blended to obtain a refractory aggregate. This refractory aggregate and mineral composition
CA, CA ₂ , and C ₂ AS, and the chemical component is CaO 31.5% by weight,
Alumina cement comprising an alumina cement material of 66.0% by weight of Al ₂ O ₃ and 2.5% by weight of SiO ₂ was blended in a ratio shown in Table 3, and mixed with an omni mixer manufactured by Chiyoda Giken Kogyo Co., Ltd. for 20 minutes to obtain a mixture of the present invention. Amorphous refractories were manufactured. The procedure was performed in the same manner as in Example 1 except that 9 parts by weight of water was added to 100 parts by weight of the amorphous refractory and kneaded with a mortar mixer in a constant temperature room at 30 ° C. The results are also shown in Table 3.

<Materials> Refractory aggregate d: fused alumina, commercially available refractory aggregate e: calcined alumina, commercially available

[0076]

[Table 3]

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

Example 4 Example 3 was repeated 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. Performed similarly. The results are also shown in Table 4.

<Materials Used> Refractory aggregate f: Sintered magnesia spinel, commercially available Refractory aggregate g: Sintered magnesia, commercially available

[0080]

[Table 4]

Example 5 Except that 100 parts by weight of an amorphous refractory consisting of 10 parts by weight of alumina cement and 90 parts by weight of refractory aggregate were mixed with 0.05 part by weight of an additive of the type shown in Table 5 Performed as in Example 3. Table 4 shows the results.

<Materials Used> Additive C: sodium polyacrylate, commercial product Additive D: sodium citrate, commercial product

[0083]

[Table 5]

Example 6 The mineral composition was CA, CA ₂ and C ₂ AS, and the chemical composition was CaO 3
Alumina cement materials of 0.0% by weight, 65.0% by weight of Al ₂ O ₃ , and 5.0% by weight of SiO ₂ were put into a batch-type ball mill, and alumina cements having different Blaine values were prototyped by changing the pulverization time. Prototype alumina cement 10 parts by weight and refractory aggregate 90
The procedure was performed in the same manner as in Example 3 except that the parts by weight were blended. The results are also shown in Table 6.

[0085]

[Table 6]

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

Example 7 The mineral composition was CA, CA ₂ and C ₂ AS, and the chemical composition was CaO 3
Various raw materials are blended so as to be 2.0% by weight, Al ₂ O ₃ 64.0% by weight, and SiO ₂ 4.0% by weight. By changing the vitrification rate, alumina cement materials having different vitrification rates were produced. The procedure was performed in the same manner as in Example 1 except that the produced alumina cement material was pulverized by a batch ball mill and the Blaine value was adjusted to 4,900 cm ² / g. The results are also shown in Table 7.

[0088]

[Table 7]

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

Example 8 A CaO raw material, an Al ₂ O ₃ raw material, and a SiO ₂ raw material were blended, melted in an electric furnace, and then quenched by high-pressure cooling air to synthesize a clinker having a predetermined mineral composition. . Compounding 75 parts by weight of the synthesized clinker and 25 parts by weight of α-Al ₂ O ₃ , adjusting the Blaine value according to the pulverization time, pulverizing with a batch-type ball mill to about 4,800 cm ² / g, Alumina cement was manufactured. When the mineral composition of the manufactured alumina cement was measured, CA, CA ₂ , C ₂ AS, and α-Al ₂ O ₃ were identified. In addition, chemical analysis was measured in the same manner. Table 8 shows the results. The procedure was performed in the same manner as in Example 1 except that this alumina cement was used. The results are also shown in Table 8.

<Materials Used> α-Al ₂ O ₃ : Commercial product, average particle size 50 μm, BET specific surface area
0.6m ² / g

[0092]

[Table 8]

Example 9 Example 9 was carried out in the same manner as in Example 8, except that the alumina cement material having the chemical composition shown in Table 9 was used. The results are also shown in Table 9.

[0094]

[Table 9]

Example 10 As an aggregate (aggregate) of 5 to 3 mm, refractory aggregate d 40% by weight, 3
45% by weight of refractory aggregate as 1mm aggregate (aggregate) 1mm
As the lower aggregate (aggregate), refractory aggregate d 10% by weight, and 200
As the aggregate under the mesh (aggregate), 5% by weight of refractory aggregate e was blended to obtain a refractory aggregate. This refractory aggregate and mineral composition
CA, CA ₂ , C ₂ AS, and α-Al ₂ O ₃ and the chemical component is CaO 2
Example 8 was carried out in the same manner as in Example 8, except that 4.5% by weight, 73.5% by weight of Al ₂ O ₃ , and 2.0% by weight of SiO ₂ were mixed in the proportions shown in Table 10. The results are shown in Table 10.

[0096]

[Table 10]

Example 11 The same procedures as in Example 8 were carried out except that alumina cement was used in an amount of 10 parts by weight, refractory aggregate was used in an amount of 90 parts by weight, and aggregates, aggregates, aggregates, and aggregates shown in Table 11 were used. Performed similarly.
The results are shown in Table 11.

[0098]

[Table 11]

Example 12 Except that 0.05 part by weight of an additive of the type shown in Table 12 was added to 100 parts by weight of an amorphous refractory composed of 10 parts by weight of alumina cement and 90 parts by weight of refractory aggregate. Performed as in Example 8. Table 12 shows the results.

[0100]

[Table 12]

Example 13 The mineral composition was CA, CA ₂ , and C ₂ AS, and the chemical component was CaO 3
75% by weight of alumina cement material of 0.0% by weight, 65.0% by weight of Al ₂ O ₃ and 5.0% by weight of SiO ₂ and 25% by weight of α-Al ₂ O ₃ Prototypes of different alumina cements were manufactured. The procedure was performed in the same manner as in Example 8 except that 10 parts by weight of the prototype alumina cement and 90 parts by weight of the refractory aggregate were mixed. The results are shown in Table 13.

[0102]

[Table 13]

Example 14 The mineral composition was CA, CA ₂ , and C ₂ AS, and the chemical component was CaO 3
Various raw materials are blended so as to be 0.0% by weight, Al ₂ O ₃ 65.0% by weight, and SiO ₂ 5.0% by weight. By changing the vitrification rate, alumina cement materials having different vitrification rates were produced. Performed in the same manner as in Example 8 except that 75% by weight of the produced alumina cement material and 25% by weight of α-Al ₂ O ₃ were blended and pulverized by a batch ball mill, and the Blaine value was adjusted to 4,900 cm ² / g. Was. The results are shown in Table 14.

[0104]

[Table 14]

Example 15 26% by weight of CaO, 72% by weight of Al ₂ O ₃ , 2.0% by weight of SiO ₂ , 0.1% of TiO ₂
Using an alumina cement substance having a chemical composition of 0.5% by weight, Fe ₂ O ₃ 0.5% by weight, and 0.1% by weight of MgO, using an alumina cement prepared in the same manner as in Example 8 and a commercially available alumina cement γ An amorphous refractory was manufactured in the same manner as in Example 8, and was subjected to φ50 using a snake pump at an outside temperature of 35 ° C.
A 20 m distance was pumped using a mm pipe. The amorphous refractory using the alumina cement of the present invention had good fluidity even after pumping, and had good workability without problems such as pipe clogging. In contrast, amorphous refractories using commercially available alumina cement cause agglomeration in the pipe,
Hardening of the kneaded material was observed at the pipe outlet.

[0106]

The alumina cement material of the present invention, the alumina cement containing it, and the amorphous refractory using the same can ensure high fluidity and pot life which cannot be obtained by conventional products. There was no problem in both the curability and strength development. When the alumina cement material of the present invention, the alumina cement containing the same, and the amorphous refractory using the same are used in the field of refractories, it is possible to cope with labor-saving construction methods such as pump construction and vibration-free construction. , and the occurrence of curing trouble of the kneaded product in the middle construction seen in conventional products can be prevented. Further, it can be used as a lining material for a chemical plant or as a civil engineering building material in which fluidity and pot life are regarded as important. Furthermore, it is widely applicable to hydraulic ceramics, catalyst materials, corrosion-resistant materials, and the like.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-54-65726 (JP, A) JP-A-7-2322941 (JP, A) JP-B-47-40694 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) C04B 7/32 C04B 28/06

Claims (3)

(57) [Claims] 1. The mineral composition is CaO.Al ₂ O ₃ , CaO.2Al
₂ O _3, and a _{2CaO · Al 2 O 3 · SiO} 2, chemical composition CaO
10 to 35 % by weight, Al ₂ O ₃ 64 to 85 % by weight, and SiO ₂ 0.6 to 1
An alumina cement material, which is 0% by weight and the total amount of impurities TiO ₂ , Fe ₂ O ₃ , and MgO is 5.2 % by weight or less. And wherein α-Al ₂ O _3, alumina cement comprising the alumina cement material of claim 1 Symbol placement. 3. An amorphous refractory comprising the alumina cement according to claim 2 and a refractory aggregate.