JP2000016843A - Alumina cement, alumina cement composition, its amorphous refractory, and spay application using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an amorphous refractory not needing its scrapping, even when left in a device after the finish of a spray application, capable of being stored, used also at the next day or later, reducing the cost of the application and saving labors, and having a long pot life, to provide an alumina cement composition, and to provide a method for spraying and applying the amorphous refractory. SOLUTION: Calcium aluminate comprises crystalline portions and amorphous portions, and has a mineral composition comprising 60-95 wt.% of CaO.2Al2O3, 5-30 wt.% of 2CaO.Al2O3.SiO2, and <=10 wt.% of CaO.Al2O3. An alumina cement comprises the calcium aluminate and α-alumina having an average particle diameter of <=10 μm and a BET specific surface area of <=5 m2/g. An alumina cement composition comprises the alumina cement and a curing retardant. An amorphous refractory comprises the alumina cement composition and a refractory aggregate. A method for spraying and applying the amorphous refractory comprises combinedly using the amorphous refractory and an accelerating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a calcium aluminate, an alumina cement, an alumina cement composition, an amorphous refractory, and the like used as a lining material for a blast furnace tapping gutter, a mixed iron wheel, a ladle, a tundish and the like. The present invention relates to a spraying construction method using the same.

[0002]

2. Description of the Related Art Spraying irregular shaped refractories has conventionally been practiced. Recently, wet spraying of amorphous refractories has been carried out in comparison with pouring due to the fact that formwork is not required, partial repair is easy, and dust generation and rebound loss are small. It has attracted attention because it can save a lot of labor. The wet spraying method is a method in which a material in a kneaded state is pumped by a pump, transported to a spraying nozzle, a quick-setting agent is added to the spraying nozzle together with compressed air, and sprayed onto a workpiece. Kimiaki 57-
JP 7350, JP-B-62-21753, JP-B 2-
No. 33665). However, conventional wet spraying is suitable for large-scale construction, but in the case of small-scale construction, there is a problem that the cost is increased due to a large loss of material.
In particular, amorphous refractories using alumina cement as a binder usually condense within one day after kneading, so after the completion of the construction, the amorphous refractories remaining in the device are extracted and discarded. It is the current situation.

As a result of intensive studies on the above problems, the present inventor has found that the above problems can be solved by using an amorphous refractory containing a specific calcium aluminate, alumina cement, or an alumina cement composition. And found that the present invention was completed.

[0004]

That SUMMARY OF THE INVENTION The present invention contains a crystalline and an amorphous, the mineral composition of the crystalline CaO · 2Al ₂ O ₃
There 60-95 _{wt%, 2CaO · Al 2 O 3} · SiO 2 is 5 to 30% by weight, and CaO · Al ₂ O ₃ is calcium aluminate 10 wt% or less, vitrification ratio of 50% or more Alumina comprising the calcium aluminate, wherein the calcium aluminate is mixed with α-alumina having an average particle diameter of 10 μm or less and a BET specific surface area of 5 m ² / g or less. Cement, the alumina cement, and an alumina cement composition comprising the alumina cement and a setting retarder, wherein the setting retarder is phosphoric acids, boric acids, silicofluorides, oxycarboxylic acids, polycarboxylic acids, Polyoxyalkylenes, and the alumina cement composition is one or more selected from the group consisting of sugars, refractory aggregate, and the alumina cement composition It is a blended amorphous refractory, and the amorphous refractory is transported to a spray nozzle by a pressure pump, a quick-setting agent is added to the amorphous refractory together with compressed air by a spray nozzle, and spraying is performed by spraying. In this spraying method, the quick-setting agent is one or more selected from the group consisting of lithium compounds, aluminates, silicates, and calcium aluminates.

Hereinafter, the present invention will be described in detail. The calcium aluminate in the present invention is a CaO source such as limestone or quick lime, an Al ₂ O ₃ source such as high-purity alumina or bauxite obtained by purifying a natural material such as red bauxite by a purification method such as a Bayer process, and A SiO ₂ source such as silica stone or silica is blended so as to have a predetermined component ratio, and melted and / or fired in equipment such as an electric furnace, a reverberatory furnace, a vertical furnace, a flat furnace, a shaft kiln, and a rotary kiln. The obtained clinker is pulverized and contains crystalline and amorphous. When producing the calcium aluminate of the present invention by a melting method, a CaO source, an Al ₂ O ₃ source, and a SiO ₂
The source is mixed at a predetermined ratio, or, mixed and pulverized, or after partial mixing, further mixed and pulverized, for example, using an electric furnace
The clinker obtained by melting at a temperature of 1600 ° C. or more is pulverized to obtain the calcium aluminate of the present invention. When the calcium aluminate of the present invention is produced by the calcination method, the clinker obtained by calcining the raw materials similarly mixed at a temperature of 1,000 to 1,600 ° C. using a rotary kiln is pulverized to grind the calcium aluminate of the present invention. An aluminate is obtained. In the present invention, the crystalline mineral composition of calcium aluminate and its ratio are important,
When CaO is C, Al ₂ O ₃ is A, and SiO ₂ is S, CA ₂
It is important to include the mineral composition of C ₂ AS. Further, assuming that TiO ₂ is T and Fe ₂ O ₃ is F as calcium aluminate, in addition to the mineral composition of CA ₂ , C ₂ AS and CA, CT and C ₄ generated by impurities mixed from the raw material are further added. Those containing a mineral composition designated as AF or the like can also be used.

As a method of quantifying the mineral composition, there are a method of measuring the intensity ratio of diffraction lines, an internal standard method, a Zevin method, an X-ray diffraction peak separation method, and the like. In the present invention, any of these methods can be used for quantification. . The method of measuring the intensity ratio of diffraction lines referred to here is a value that relatively expresses the diffraction intensity of each mineral, 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 whose concentration is known, utilizing the fact that a linear relationship is obtained between the concentration and the diffraction line intensity ratio. The Zevin method measures the average mass absorption coefficient of a sample and the diffraction line intensity ratio,
This is a method of quantifying each crystal phase by solving an n-order simultaneous equation. The average mass absorption coefficient can be calculated by quantifying the components of a sample by X-ray fluorescence analysis or chemical analysis. In addition, it can be quantified by an X-ray diffraction peak separation method. In this method, measurement is performed from a crystal or a glass phase of a sample. In the present invention, any method can be used to quantify the mineral composition and the vitrification rate.However, the measurement is simple, and the use of the diffraction line intensity ratio measurement method or the Zevin method is accurate. preferable.

In the present invention, the proportion of the crystalline mineral of calcium aluminate is 60 to 95% by weight for CA _{2 and} 5 for C ₂ AS.
It is important to manufacture so that 3030% by weight and CA is 10% by weight or less. If the content of CA ₂ exceeds 95% by weight, the pot life extending effect tends to decrease, and if it is less than 60% by weight, the reactivity with the quick setting agent tends to decrease. The chemical component of the calcium aluminate of the present invention is CaO 20-30% by weight, Si
It is important that the content of O _{2 is} 15 to 5% by weight and the balance is Al ₂ O _{3. The} content of CaO is 22 to 28% by weight and the content of SiO _{2 is} 12 to 6% by weight.
Al ₂ O ₃ is more preferable. When the content of CaO exceeds 30% by weight, the amount of CA generated tends to increase, and the effect of extending the pot life tends to decrease. Further, CaO is the likely generated by CaO · 6Al ₂ O ₃ is a non-hydraulic mineral less than 20 wt%, strength development tends to decrease.

[0008] The vitrification rate of calcium aluminate is
When CA ₂ and C ₂ AS are contained in the crystal, the higher the effect, the longer the pot life is obtained. Therefore, it is important that the vitrification ratio is 50% or more. If the vitrification ratio is less than 50%, the pot life extension effect tends to decrease. The vitrification rate can be adjusted depending on the degree of cooling of the molten or fired high-temperature clinker, and rapid cooling increases the vitrification rate. For the pulverization of the clinker, it is possible to use a pulverizer such as a roller mill, a jet mill, a tube mill, a ball mill, and a vibrating mill, which are usually used for finely pulverizing a lump of powder. With these pulverizers, the clinker is pulverized to an average particle diameter of 10 μm or less. The average particle size of the calcium aluminate is related to the important properties of fluidity, curability, and strength, and is an important control point for obtaining the required properties, and is preferably 10 μm or less.
μm or less is more preferable.

The α-alumina used in the present invention is:
It is appropriately determined according to the required quality when blended into the amorphous refractory, but the fluidity, curability, strength development, spalling resistance, and the surface for reducing the shrinkage ratio, etc. Care should be taken to greatly affect the characteristics. α-alumina is intended to impart high-temperature strength and volume stability, and is a purified alumina obtained by firing a highly purified aluminum hydroxide by a Bayer process or the like with a rotary kiln. These are called high-purity alumina, Bayer alumina, easily sintered alumina, lightly burned alumina, and the like. The purity of α-alumina is preferably as high as possible, and Al ₂ O ₃ 90
% By weight or more, more preferably 98% by weight or more.
Al if alumina is produced by normal process
A purity of 90% by weight or more of ₂ O ₃ can be ensured. Furthermore, α
- alumina, a Na ₂ O content of the impurities in addition to the Al ₂ O ₃ purity problems, when used as a alumina cement Na ₂ O amount is large, reduction of the fluidity, reduction in the refractory, and high temperature In order to avoid problems such as shrinkage, the amount of Na ₂ O is preferably small, preferably 0.5% by weight or less, more preferably 0.3% by weight or less. α-alumina is
The primary particle diameter before pulverization is about 20 to 100 μm in average particle diameter, preferably 30 to 60 μm, and 40 to 50 μm.
m is more preferred. If it exceeds 100 μm, the sintering strength of the amorphous refractory tends to decrease, and if it is less than 20 μm, the fluidity tends to decrease. Usually, the primary particle diameter is related to the precipitation rate of aluminum hydroxide in the Bayer process. When the precipitation rate is reduced, a particle having a large particle diameter is obtained, and when it is increased, a particle having a small particle diameter is obtained. The index of the firing degree of α-alumina is a specific surface area by the BET method, preferably 5 m ² / g or less, 1 m ² / g
The following is more preferred. The degree of sintering indicates that the larger the specific surface area, the lighter the sintering type alumina. When used at a high temperature, the sintering property is excellent but the shrinkage is also large. If the specific surface area of α-alumina is large, the fluidity of the alumina cement decreases, and if it is small, the fluidity tends to improve. If the specific surface area is large, the sinterability at a high temperature is improved when blended as an amorphous refractory, but the spalling resistance tends to decrease and the shrinkage tends to increase due to oversintering. Amorphous refractories containing α-alumina having a small specific surface area tend to have low shrinkage and low sintering strength.

In the present invention, the method of mixing and pulverizing when producing alumina cement from calcium aluminate and α-alumina is such that α-alumina alone has a particle size equivalent to alumina cement, that is, an average particle diameter of 1 to 5 μm. After pulverizing to a degree, a method of mixing with the calcium aluminate or mixing a clinker of calcium aluminate and α-alumina and mixing and pulverizing is possible. In the present invention, when the clinker of calcium aluminate and α-alumina are mixed and pulverized, α-alumina is uniformly mixed in the alumina cement, so that when an amorphous refractory is used, the hardened body structure becomes uniform. This is preferable because effects such as improvement in corrosion resistance are obtained. The amount of α-alumina used is such that CaO is 5 to 15% by weight and Al ₂ O ₃ is 95 to 85% by weight in the mixture of calcium aluminate and α-alumina. α-
When the amount of alumina used is increased, the fire resistance and the sintering strength at high temperatures are increased, but the curing strength and the strength after drying are reduced, and the fluidity tends to be reduced. Also, when the CaO content is large, the corrosion resistance when used for an amorphous refractory tends to decrease.

In the present invention, it is preferable to use a curing retarder in combination from the viewpoint of having a pot life extending effect. The curing retarder used in the present invention (hereinafter referred to as a retarder) is one usually used for alumina cement, and specifically,
It is preferable to use one or more selected from the group consisting of phosphoric acids, boric acids, silicofluorides, oxycarboxylic acids, polycarboxylic acids, polyoxyalkylenes, and saccharides.

Examples of the phosphoric acids include hexametaphosphoric acid, tripolyphosphoric acid, ultraphosphoric acid, pyrophosphoric acid, and orthophosphoric acid and salts thereof. Hexametaphosphoric acid and tripolyphosphoric acid or salts thereof are preferable because of their excellent dispersing action. PH is alkaline, pH
Is more preferably 8.0 to 11.0. Examples of the salts of phosphoric acids include sodium, potassium, and calcium salts, and use of a sodium salt is preferable because of availability. Phosphoric acid having a particle size of 200 mesh or less is preferable because it is easily dissolved at the time of kneading and has excellent dispersing action, and in terms of quality, those generally marketed as pharmaceuticals and food additives can be used. .

The boric acids include boric acid and its alkali salts such as sodium salt, potassium salt and calcium salt. Of these, boric acid having a strong curing retarding action is preferred. The particle size of the boric acid is preferably as small as possible so as to be easily dissolved in water when kneaded with the cast refractory. Further, the purity of boric acids is not particularly limited, but those industrially purified at present can be used.

As the fluorosilicate, it is preferable to use sodium fluorosilicate, potassium fluorosilicate, magnesium fluorosilicate and the like. Among these, use of sodium silicofluoride is preferred because of its strong curing retarding effect. The particle size of the silicon fluoride 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, more preferably 200 mesh or less.
Although the purity of the silicon fluoride is not particularly limited,
At present, it is possible to use industrially purified products, and it is preferable to use those having a purity of the target silicofluoride of about 80% by weight or more.

As the oxycarboxylic acids, citric acid,
Gluconic acid, tartaric acid, malic acid, and lactic acid or salts thereof. Examples of the salts of oxycarboxylic acids include sodium, potassium, and calcium salts, and use of a sodium salt is preferred because of availability. The particle size of oxycarboxylic acids is less than 200 mesh,
It is preferable because it is easily dissolved at the time of kneading and has an excellent dispersing action. In terms of quality, commercially available food additives can be used.

The polycarboxylic acids include polyacrylic acids, polymethacrylic acids, copolymers of acrylic acids and methacrylic acids, and polyitaconic acids.

Examples of the polyacrylic acids include polyacrylic acid and its derivatives or alkali salts thereof, and polyacrylic acid ester copolymers and alkali salts thereof, and the copolymer is preferably a crosslinked and branched type.

Examples of polymethacrylic acids include non-functional monomers such as methyl methacrylate, monofunctional monomers such as diethylaminoethyl methacrylate, and polyfunctional monomers such as ethylene dimethacrylate. Examples include an acid or an alkali metal salt thereof, and a methacrylate synthetic resin containing a copolymer.

The acrylic acid / methacrylic acid copolymer is a copolymer of acrylic acid and methacrylic acid. The ratio of copolymerization of acrylic acid and methacrylic acid is 9/1 to 1 by weight of acrylic acid / methacrylic acid.
The ratio is preferably 4/6, and a copolymer having a ratio of 8/2 to 5/5 is more excellent in dispersing action and more preferable. A particularly preferred copolymer combination has a weight ratio of sodium acrylate / sodium methacrylate of 8/2 to 5/5. If the proportion of acrylic acids is too large, the fluidity and the pot life tend to be shortened, and if the proportion of acrylic acids is too small, the viscosity at the time of kneading becomes high, and not only is it easy to cause curing delay, Copolymerization tends to be impossible.

Examples of the polyitaconic acids include polyitaconic acid and its derivatives or alkali salts thereof, and polyitaconic acid ester copolymers and alkali salts thereof, and the copolymer is preferably a cross-linked branched type.

As the alkali salt of the polycarboxylic acid used in the present invention, a sodium salt, a potassium salt, a calcium salt and the like can be used, but the use of a sodium salt is preferred from the viewpoint of availability. Above all, it is soluble in water and has a solid content of 90% by weight or more, measured with a B-type viscometer at 25 ° C.
It is preferable to use a soluble type having a slurry viscosity of 40% by weight and a viscosity of 10,000 cps or less from the viewpoint of improving the fluidity of the alumina cement, and more preferably a viscosity of 1,000 cps or less. In the present invention, the ionicity and pH of the slurry of the polycarboxylic acids are not particularly limited, but when blended with alumina cement, in order to obtain greater fluidity, the polycarboxylic acids are anionic, and PH of 1% by weight slurry at 25 ° C
Is important from neutral to alkaline, especially pH
Is preferably 7.5 to 10. The polycarboxylic acids are preferably of a powder type from the viewpoint of handling. The pulverization of the polycarboxylic acids can be carried out by subjecting the liquid product to a drying treatment with a drier such as a spray drier.

Specific examples of the polyoxyalkylenes include copolymers of polyalkylene glycol acrylate, polyalkylene glycol alkenyl ether-maleic anhydride copolymer, and polyalkylene glycol monoester monomer / methacrylic acid. Acid copolymers and the like can be mentioned.

The saccharides include aldehydes and ketones of polyhydric alcohols, and acids and polyhydric alcohols themselves and derivatives and substituted products thereof, and specific examples include glucose, fructose, dextrin, and sucrose. .

The combination of types of retarders can be appropriately selected depending on the alumina cement, and is not particularly limited. The combination can be changed according to the material composition. The use amount of these retarders is preferably 0.2 to 10 parts by weight based on 100 parts by weight of alumina cement from the viewpoint of obtaining an effect of extending the pot life.

In the present invention, the method of blending the retarder is not particularly limited, and each additive is blended so as to have a predetermined ratio, and clinker which has been ground in advance, a V-type blender, a corn blender, a Nauta mixer , Pan-type mixer, omni-mixer, etc., or uniformly mixed, or after mixing with clinker at a predetermined ratio, mix and pulverize with a pulverizer such as a vibration mill, a tube mill, a ball mill, and a roller mill. It is possible.
Furthermore, according to the invention, individual retarders or mixtures of retarders are treated at a temperature of from 100 to 200 ° C. for at least 30 minutes, preferably at least 6 minutes.
Heat treatment of drying or light baking for 0 to 180 minutes is preferable because the fluidity when blended with alumina cement is improved, and the effect of heat treatment at 120 to 180 ° C. is particularly remarkable. Retarder of the present invention, GC-MS, C ¹³ -NMR
It can be analyzed by instrumental analysis such as HPLC, ion chromatography, FT-IR, and activation analysis.

In the present invention, the alumina cement composition and the refractory aggregate are blended to form an amorphous refractory. Examples of the refractory aggregate include magnesia such as fused magnesia, sintered magnesia, natural magnesia, and light-burned magnesia, magnesia spinel such as fused magnesia spinel and sintered magnesia spinel, fused alumina, sintered alumina, light-fired alumina, and Alumina such as sintered alumina, silica fume, colloidal silica, light-burned alumina, and ultrafine powder such as easily sintered alumina, other, fused silica, calcined mullite,
Chromium oxide, bauxite, andalusite, sillimanite, chamotte, quartzite, olivine, clay, zircon,
Examples include zirconia, dolomite, pearlite, vermiculite, brick waste, pottery waste, silicon nitride, boron nitride, silicon carbide, and iron silicon nitride. In particular, in the amorphous refractory of the present invention, one or more refractory aggregates selected from magnesia spinel, alumina, and ultrafine powder are used in terms of corrosion resistance, durability, and fire resistance. Is preferred.

The magnesia spinel is prepared by mixing a MgO source such as magnesium hydroxide or calcined magnesia and an Al ₂ O ₃ source such as aluminum hydroxide or calcined alumina so as to have a predetermined ratio. Spinel clinker obtained by reacting and sintering at a temperature of about 1,800 to 1,900 ° C using a firing device, and melting magnesia spinel melted by a melting device such as an electric furnace, crushed to a predetermined size, and sieved Further, a mixture of the baked material and the melted material may be used. The weight ratio of MgO / Al ₂ O ₃ in the magnesia spinel, 1 / 1-0.
1/1 is preferred, and 0.4 / 1 to 0.2 / 1 is more preferred from the viewpoint of excellent durability.

Alumina is a material obtained by sintering and / or melting an Al ₂ O ₃ source such as aluminum hydroxide or calcined alumina by a firing device such as a rotary kiln or a melting device such as an electric furnace. It is crushed and sieved and is an aluminum oxide whose mineral composition is indicated as α-Al ₂ O ₃ or β-Al ₂ O _3, such as sintered alumina, calcined alumina, and easily sintered alumina. Usually, it is most preferable to use α-alumina containing 90% by weight or more of Al ₂ O ₃ . Further, it is also possible to use alumina / zirconia clinker having improved heat-resistant spalling property obtained by melting alumina and zirconia.

In the present invention, the refractory aggregate is usually 5 to 3
Particles having a particle size of mm, 3 to 1 mm, 1 to 0 mm, under 200 mesh, under 325 mesh, etc. are blended according to required physical properties.

In the present invention, as the refractory aggregate, it is possible to use ultrafine powder having a fine particle diameter. Ultrafine powder is a refractory fine powder in which particles having a particle diameter of 10 μm or less account for 80% by weight or more, and have an average particle diameter of 1 μm.
m and a specific surface area of 10 m ² / g or more according to the BET method are preferable, because when blended into an amorphous refractory, fluidity can be secured and high strength can be obtained. Specifically, inorganic fine powders such as silica fume, colloidal silica, easily sintered alumina, amorphous silica, zircon, silicon carbide, silicon nitride, chromium oxide, and titanium oxide can be used.
The use of silica fume, colloidal silica, and easily sintered alumina is preferred.

The mixing ratio of the amorphous refractory of the present invention should be appropriately determined depending on the construction site, and is not particularly limited. The method for producing an amorphous refractory of the present invention is not particularly limited, and is in accordance with a normal method for producing an amorphous refractory, and blends each material in a predetermined ratio.
V-type blender, cone blender, Nauta mixer,
It is also possible to perform uniform mixing using a mixer such as a pan-type mixer and an omni mixer, or to directly weigh the mixture into a kneading machine when performing kneading at a predetermined ratio.

Further, the amorphous refractory of the present invention may include a foaming material such as metal aluminum or metal magnesium which reacts with alkaline water to generate hydrogen gas, an organic fiber such as vinylon fiber, polypropylene fiber, and vinyl chloride fiber. N ₂ gas generating exploded fibers are fibers that generates N ₂ gas by heating, a basic colloids such aluminum lactate, and, if necessary explosion prevention materials such as humic acids, explosion object of preventing the time of curing the dried It is possible to mix.

Furthermore, in order to avoid material separation between the amorphous refractory of the present invention and moisture, a thickener such as methylcellulose, carboxymethylcellulose, modified polyacrylamide or a copolymer thereof, and polyvinyl alcohol is blended. Is also possible.

The amount of kneading water used for kneading the amorphous refractory is set to such an extent that it can be poured normally, and is greatly affected by the particle size composition and the porosity of the refractory aggregate. It is about 5 to 8 parts by weight based on parts by weight.

The spraying according to the present invention means that the kneaded irregular-shaped refractory is transported from a mixer to a spraying nozzle by a pressure pump and the quick-setting agent is mixed with the compressed air into the irregular-shaped refractory by the spraying nozzle. It is to be constructed.

The quick-setting agent used in the present invention has an action of coagulating the refractory sprayed onto the coated surface so as not to cause dripping, and can be used in either liquid or powder form. It is preferable to use a powder quick-setting agent in order to minimize the amount of water in the irregular-shaped refractory to be sprayed and to make it dense. As for the method of mixing the quick-setting agent, it is preferable to mix the irregular-shaped refractory from the quick-setting agent injection port using compressed air as a carrier so as to be uniformly dispersed. When a liquid quick-setting agent is mixed with an amorphous refractory, it is preferable to use an aqueous solution that is as thick as possible because the water content is reduced and the density is increased. As the quick setting agent, lithium compounds, aluminates, silicates, calcium aluminates, and other hardening accelerators can be used. In particular, it is preferable to mix one or two or more selected from lithium salts, aluminates, silicates, and calcium aluminates since the quick-setting property is improved and sag is prevented from occurring.

Examples of the lithium compound include lithium hydroxide, lithium chloride, lithium carbonate, lithium citrate, lithium nitrate, and lithium fluoride. Lithium chloride is preferred because of its excellent quick-setting properties. Examples of the aluminate include sodium aluminate and potassium aluminate, and it is preferable to use a powder or aqueous solution of sodium aluminate that is easily available, inexpensive, and has excellent quick-setting properties. Silicates include sodium silicate and potassium silicate, and are easily available.
It is preferable to use inexpensive sodium silicate powder or aqueous solution. The calcium aluminates, is calcium aluminate having a quick-setting property, in particular those containing the mineral composition of the C ₃ A or C ₁₂ A _7. The quick setting property is improved as the particle size of the calcium aluminates is smaller, and the average particle size is preferably 45 μm or less.

The amount of the quick setting agent used is preferably 0.01 to 5 parts by weight in terms of solid content based on 100 parts by weight of the amorphous refractory. If it is less than 0.01 part by weight, the quick-setting property is insufficient, dripping or shrinkage tends to occur in the sprayed amorphous refractory, and if it exceeds 5 parts by weight, it hardens rapidly and the strength decreases. And the corrosion resistance tends to decrease.

[0039]

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

Experimental Example 1 A CaO source, an Al ₂ O ₃ source and a SiO ₂ source were blended at a predetermined ratio.
After melting at 1,400 to 1,600 ° C using an electric furnace, quenching or cooling is performed to produce clinker.
Calcium aluminate was prepared by pulverizing to a size of μm. Table 1 shows the chemical components and mineral compositions. In a 20 ° C constant temperature room, 10 parts by weight of calcium aluminate, 70 parts by weight of refractory aggregate A, 10 parts by weight of refractory aggregate B, 10 parts by weight of refractory aggregate C, and 6.2 parts by weight of water are mixed and mixed with a mortar mixer.
The mixture was kneaded for a minute to produce an amorphous refractory. The vitrification rate, fluidity, and pot life of the produced amorphous refractory were measured. The results are also shown in Table 1.

<Materials> Al ₂ O ₃ source: calcined alumina, 150 μm below CaO source: quick lime powder, 1 mm below SiO ₂ source: silica powder, 1 mm below Refractory aggregate A: electrofused alumina, 5-1 mm 20 weight Part, 1-0
mm20 parts by weight, 48F15 parts by weight, 325 F15 parts by weight Refractory aggregate B: Sintered spinel, 200 F Refractory aggregate C: Ultra fine powder, sintered alumina, average particle diameter 1.2 μm
m

<Measurement method> Chemical component: Analyzed according to JIS R 2522 Mineral composition: Diffraction intensity ratio d value by X-ray diffractometer “RADIIB” manufactured by Rigaku Corporation, CA = 4.67Å, CA ₂ = 4.45Å, C ₂ AS =
Using the intensity of the diffraction line of 2.85 °, α-alumina = 2.55 °
Calculated by Zevin method Vitrification: Calculated in the same manner as mineral composition Fluidity: Kneaded for 3 minutes and then left for 30 minutes. Pot life: The time it took to remove the irregular shaped refractory into a plastic bag and lose its fluidity

[0043]

[Table 1]

As is clear from the table, the amorphous refractory blended with the calcium aluminate of the present invention has better fluidity and a significantly longer pot life than the comparative example.

Experimental Example 2 40 parts by weight of pulverized clinker and 60 parts by weight of a commercially available α-alumina having an average particle diameter and a BET specific surface area shown in Table 2 were mixed to obtain an alumina cement containing about 10% by weight of CaO. Except for the above, the procedure was the same as in Experimental Example 1. The results are also shown in Table 2.

<Measurement method> Average particle diameter: using a laser diffraction particle size distribution analyzer manufactured by Shimadzu Corporation BET specific surface area: using a Cantersorb manufactured by Yuasa Ionics

[0047]

[Table 2]

As shown in the table, the amorphous refractory blended with the alumina cement of the present invention had better fluidity and a significantly longer pot life than the comparative example.

Experimental Example 3 Table 3 was added to 100 parts by weight of pulverized clinker.
Was carried out in the same manner as in Experimental Example 1 except that the alumina cement composition was manufactured by mixing the retarder shown in (1) and pulverizing to an average particle diameter of 5 μm with a vibration mill. The results are also shown in Table 3.

<Materials used> Delaying agent a: sodium tripolyphosphate, commercial product Delaying agent b: sodium citrate, commercial product Delaying agent c: sodium polyacrylate, commercial product Delaying agent d: sodium silicofluoride, commercial product delaying agent e: boric acid, commercially available retarder f: polyalkylene glycol monoester monomer / methacrylic acid copolymer, commercially available retarder g: sucrose, commercially available retarder h: sodium lignin sulfonate, commercially available product

[0051]

[Table 3]

As shown in the table, the amorphous refractory blended with the alumina cement composition of the present invention had better fluidity and a significantly longer pot life than the comparative example.

Experimental Example 4 The amorphous refractory blended with the alumina cement composition used in Experiment Nos. 3 to 8 of Experimental Example 3 was transported to a spray nozzle by a pressure pump and is shown in Table 4 together with compressed air by the spray nozzle. A quick setting agent was added to the irregular refractories and sprayed. After spraying construction, the specimen cut out to a predetermined size from each construction body cured for 24 hours was used as a test piece. The results are also shown in Table 4.

<Materials used> Quick setting agent α: lithium carbonate, commercially available product Quick setting agent β: anhydrous sodium aluminate, commercially available product Quick setting agent γ: sodium silicate, commercially available product Quick setting agent δ: calcium aluminates , Mineral composition C ₃ A 95
% By weight, C ₁₂ A ₇ 5% by weight Quick setting agent ε: calcium aluminates, mineral composition C ₁₂ A ₇
90% by weight, CA 10% by weight Quick setting agent ζ: Calcium aluminates, mineral composition C ₁₂ A ₇
50% by weight, 50% by weight of CA Quick-setting agent η: Sodium hydroxide, commercially available

<Measurement method> Setting time: Pressing the amorphous refractory after spraying with a finger until elasticity is lost Curing strength: Cut out to 4 × 4 × 16 cm and measured with a hydraulic measuring machine Dry strength: Specimen After drying at 110 ° C for 24 hours, let it cool down to room temperature and measure it with a hydraulic pressure measuring device. Firing strength: Put the dried test piece in a siliconite electric furnace, and heat up to 1,000 ° C at a rate of 10 ° C / min at 1,000 ° C. Above, the temperature was raised to 1,500 ° C at 5 ° C / min, held for 3 hours, allowed to cool to room temperature, and measured with a hydraulic pressure measuring machine. Shrinkage: 1,50
Residual linear change rate after firing at 0 ° C Corrosion resistance: A test piece cut into 4 × 4 × 16cm is 110 ° C
, And calcined at 1,500 ° C for 3 hours to obtain CaO / SiO ₂ = 2.
0. Measured the erosion dimension in the depth direction after immersing for 3 hours in a high-frequency furnace at 1,550 ° C containing 500 g of slag containing 10% by weight of total Fe. If the erosion dimension exceeds 3.0 mm, it cannot be used as a refractory. Appearance observation: Observe the appearance of dripping on the sprayed surface immediately after spraying.

[0056]

[Table 4]

As shown in the table, the amorphous refractory blended with the alumina cement composition of the present invention had higher strength, lower shrinkage, and better corrosion resistance than the comparative example.

[0058]

According to the present invention, the calcium aluminate, the alumina cement, the alumina cement composition, the irregular refractory obtained by blending them, and the spraying method according to the present invention can be used even if spraying is completed. There is no need to dispose of the amorphous refractories left inside, and it can be stored and used after the next day. Therefore, it is possible to reduce costs, especially when there is no kneading equipment such as a mixer at the construction site, it is only necessary to knead at the factory, transport it to the site with an agitator, and knead the quick-setting agent at the construction site. Labor can be achieved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // (C04B 28/06 22:06) 103: 24 F-term (reference) 4G012 MA01 MB02 PB01 PB03 PB05 PB06 PB13 PB17 PB19 PB36 PC05 PC06 PD03 PE04 4G033 AA02 AA04 AA06 AB03 AB04 AB08 AB21 AB23 4K051 AA01 AA06 LA11

Claims (11)

[Claims] Claims: 1. A crystalline mineral composition comprising 60 to 95% by weight of CaO.2Al ₂ O ₃ having a crystalline mineral composition, 2CaO.Al
A calcium aluminate characterized in that ₂ O ₃ · SiO ₂ is 5 to 30% by weight and CaO · Al ₂ O ₃ is 10% by weight or less. 2. The calcium aluminate according to claim 1, wherein the degree of vitrification is 50% or more. 3. An alumina cement comprising the calcium aluminate according to claim 1 or 2. 4. An alumina cement comprising the calcium aluminate according to claim 1 and α-alumina. 5. The alumina cement according to claim 4, wherein the α-alumina has an average particle diameter of 10 μm or less and a BET specific surface area of 5 m ² / g or less. 6. An alumina cement composition comprising the alumina cement according to any one of claims 3 to 5. 7. An alumina cement composition comprising the alumina cement according to claim 3 and a setting retarder. 8. A curing retarder comprising a phosphoric acid, boric acid, silicofluoride, oxycarboxylic acid, polycarboxylic acid,
8. A compound selected from the group consisting of polyoxyalkylenes and saccharides, or one or more of them.
The alumina cement composition as described in the above. 9. An amorphous refractory comprising a mixture of a refractory aggregate and the alumina cement composition according to any one of claims 6 to 8. 10. The refractory of claim 9 is transported to a spray nozzle by a pressure pump, and a quick-setting agent is added to the refractory together with compressed air by the spray nozzle, and spraying is performed. Spray construction method. 11. The method according to claim 10, wherein the quick setting agent is one or more selected from the group consisting of lithium compounds, aluminates, silicates, and calcium aluminates. Spray construction method.