JPH0781995A - Cement composition - Google Patents

Abstract

PURPOSE:To prolong the pot life without deteriorating fluidity and secure the appropriate setting time and excellent strength developing property by incorporating calcium aluminate, acrylate-methacrylate copolymer, carbonate, borate and carboxylic acids. CONSTITUTION:Calcium aluminate is formed by mixing an alumina material such as bauxite and a calcia material such as limestone in a ratio to form a specified mineral, melting or burning the mixture and crushing the obtained hydraulic mineral. The acrylate-methacrylate copolymer is a copolymer of acrylic acid (including its derivative, polyacrylic acid and their alkali salt) or the inorg. salt and methacrylic acid (as mentioned above) or the inorg. salt. Sodium carbonate, sodium hydrogen carbonate, etc., should preferably be used as the carbonate. The borate is expressed by H3BO3. The carboxylic acids are used to prolong the pot life when a castable is kneaded and to improve fluidity. Such materials are combined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement composition, in particular, a cement which can prolong the pot life, obtain an appropriate setting time, and secure good fluidity and strength development. It relates to a composition.

The cement composition of the present invention can be widely used not only in the field of refractory materials such as refractory concrete but also in the field of civil engineering and construction materials. The% in the present invention is% by weight unless otherwise specified.

[0003]

2. Description of the Related Art Conventionally, sugars and carboxylic acids have been used in order to extend the pot life of alumina cement to obtain an appropriate setting time and to secure good fluidity and strength development. Alumina cement, which is a combination of alumina, phosphoric acid, boric acid, etc., as a hardening modifier for alumina cement has been proposed (HIGH-ALMINA CEMENTS AND CONCRE
TES TDROBSON P129-133 1962 issued).

However, this type of alumina cement has a problem that it cannot secure a pot life when blended in castables and lacks fluidity and strength development.

[0005] Further, an alumina cement containing a setting modifier composed of citric acid, tartaric acid, and a sulfonic acid type anionic surfactant in combination, an alumina cement containing a setting modifier composed of hydroxycarboxylic acid and an inorganic carbonate, water-soluble Of polyacrylic acid or a salt thereof and an alkali metal carbonate and / or a hydroxycarboxylic acid or a salt thereof in combination with alumina cement, a water-soluble polymethacrylic acid or a salt thereof, a methacrylic acid-acrylic acid copolymer or a salt thereof, ,
Alumina cement containing an alkali metal carbonate and / or a hydroxycarboxylic acid or a salt thereof, and
Alumina cement and the like in which a dispersant comprising a water-soluble polyacrylic acid and / or polymethacrylic acid, a hydroxycarboxylic acid, and an inorganic carbonate is also used have been proposed (JP-A-49-52216 and JP-A-50). -28090, JP 55-7
5947, JP-A-55-75948, and JP-A-55-121
No. 933 publication).

However, even when these alumina cements are compounded into castables, the functions required for the alumina cements, in particular, long pot life can be obtained, appropriate curing time, good fluidity, and good strength development. The function of ensuring sex was not fully satisfied.
That is, when the pot life is extended and the fluidity is improved, the curing time is delayed and the strength development is deteriorated. vice versa,
When trying to improve strength development, fluidity deteriorates,
There were issues such as the strong tendency to conflict with the fact that the pot life was shortened.

[0007] In recent years, constructions have become larger in size and have a different shape, and there is a demand for securing a working life and further improving fluidity, and it has been difficult for the prior art to cope with this.

As a result of intensive studies to solve these problems, the inventor of the present invention can obtain a long working life by combining a specific material without impairing the fluidity, and an appropriate curing time and excellent The present invention has been completed with the knowledge that the strength development can be secured.

[0009]

That is, the present invention is a cement composition containing calcium aluminate, an acrylic acid-methacrylic acid copolymer, a carbonate, boric acid, and a carboxylic acid.

The present invention will be described in detail below.

The calcium aluminate according to the present invention means purified alumina such as bauxite, aluminum residual ash, Bayer alumina, fused alumina, and sintered alumina as an alumina raw material, and limestone, calcium carbonate, quick lime as a calcia raw material. Hydrous minerals obtained by melting and / or firing in an electric furnace, reverberatory furnace, open hearth furnace, converter, rotary kiln, etc. , Ball mill, tube mill, vibration mill, jet mill, roller mill,
And a pulverizer such as a tower mill.

The mineral composition of calcium aluminate is Ca
When O is C and Al ₂ O ₃ is A, C ₃ A, CA, C ₁₂ A ₇ , and
It is a mineral mainly composed of hydraulic calcium aluminate, such as CA _2, and can be used in crystalline or amorphous form. Mineral composition of calcium aluminate is not particularly limited, the CA and C ₁₂ A ₇ mainly, CA and C ₁₂ A ₇
The generation ratio of C ₁₂ A _{7 /} CA is preferably in the range of 0.1 to 10 in terms of the diffraction intensity ratio which is the peak ratio by the powder X-ray diffraction analysis, more preferably in the range of 0.3 to 5, and in the range of 0.5 to A value of 3 is most preferable because it exhibits an appropriate curing time and excellent strength development. If the diffraction intensity ratio is less than 0.1, the curing time tends to be delayed, while if it exceeds 10, the pot life may be extended and good fluidity may not be secured. The diffraction intensity ratio here is the diffraction intensity when irradiated with X-rays of Cu-Kα rays, and the d value of CA crystal lattice is 4.67Å and the d value of C ₁₂ A ₇ is 4.89Å.
Is the diffraction intensity ratio. The method for producing calcium aluminate of the present invention is not particularly limited, for example,
As production ratio of CA and C ₁₂ A ₇ is in the range of C ₁₂ A ₇ /CA=0.1~10, it may be a CA and C _{1 2} A ₇ were mixed to manufacture individually, CA
It is also possible to manufacture C ₁₂ A ₇ and C ₁₂ A ₇ at the same time so that the above production ratio is achieved. In particular, it is preferable to use the calcium aluminate produced by the calcination method because the strength development is excellent.

In the case of manufacturing by the firing method, the mixing ratio of raw materials is
By weight ratio, CaO is preferably 20 to 60%, Al ₂ O ₃ is preferably 80 to 40%,
More preferably, CaO is 30 to 40%, and Al ₂ O ₃ is 70 to 60%. The firing temperature of calcium aluminate is 1,000-1,600
C is preferable, and 1,200-1,500 ° C is more preferable.

[0014] Calcium aluminate of the present invention, as an _{impurity, 2CaO · Al 2 O 3 ·} SiO 2, 4CaO · Al 2 O · Fe 2 O 3, and Ca
It is possible to use those containing O ・ TiO _2, etc.
Other than O and Al ₂ O ₃ , for example, SiO ₂ , TiO ₂ , Fe ₂ O ₃ , and Mg
Impurities such as O may cause shrinkage at high temperatures and generate low melting point compounds. Therefore, the content of these impurities is preferably small.

The particle size of calcium aluminate is preferably fine because it is excellent in fluidity and strength development.
In the measurement method by Blaine method defined by 2521, the specific surface area is preferably at least 3,000 cm ² / g, more preferably at least ^{4,000cm 2 / g, 6,000cm 2 /} g or more is most preferred. The average particle size of calcium aluminate is preferably 20 μm or less, more preferably 5 μm or less. The smaller the average particle diameter is, the more thixotropic high fluidity can be exhibited when kneading with water and used, which is preferable.

The acrylic acid-methacrylic acid copolymer according to the present invention is a copolymer of acrylic acid or an inorganic salt of acrylic acid and methacrylic acid or an inorganic salt of methacrylic acid, such as sodium salt or potassium salt. Although it can be used, it is preferable to use the sodium salt because it is easily available.
Above all, it is a water-soluble polymer with solid content of 95% or more at 25 ° C.
It is preferable to use a soluble polymerization type of 40% slurry viscosity of 10,000 cps or less in order to improve the fluidity of the cement. The viscosity of the water-soluble slurry is B
It can be measured by a type viscometer, and represents the degree of polymerization, and the higher the degree of polymerization, the higher the viscosity tends to be, and in the present invention, the slurry viscosity of 40% concentration at 25 ° C. is 100 to 2,000 cps. Is preferably used, 300
It is more preferable to use the one of about 1,000 cps.

Here, acrylic acid means polyacrylic acid, acrylic acid, and a derivative of acrylic acid or an alkali salt thereof, and specifically, polyacrylic acid or an alkali salt thereof, acrylic acid or an alkali salt thereof. Examples thereof include salts, polyacrylic acid ester copolymers and alkali salts thereof. Further, as the copolymer, a cross-linked branched type copolymer is preferable.

Methacrylic acid is polymethacrylic acid, methacrylic acid, and derivatives of methacrylic acid or their alkali salts, and specifically, polymethacrylic acid or its alkali salt, methacrylic acid or its alkali salt. , And a polymethacrylic acid ester copolymer or an alkali salt thereof. Further, as the copolymer, a cross-linked branched type copolymer is preferable.

The copolymerization ratio of acrylic acid and methacrylic acid is a weight ratio of acrylic acid / methacrylic acid of 9/1 to 4
A ratio of / 6 is preferable, and particularly 8/2 to 5 /
A copolymer in the range of 5 is preferable because of its excellent dispersing action. A particularly preferred combination of copolymers is 8/2 to 5/5 sodium acrylate / sodium methacrylate. If the proportion of acrylic acid is too high, the characteristics of acrylic acid will be strong, and the fluidity and aggregation time will tend to be fast.If the proportion of acrylic acid is too low, the characteristics of methacrylic acid will be strong and the kneading will be Not only is the viscosity high, and delay of curing tends to occur, but copolymerization tends to be impossible, which is not preferable.

In the present invention, the ionicity and pH of the water-soluble slurry of acrylic acid-methacrylic acid copolymer (hereinafter referred to as the present copolymer) are not particularly limited, but when blended with calcium aluminate. , To obtain greater fluidity, this copolymer is anionic and at 25 ℃
It is important that the pH of the water-soluble slurry having a concentration of 1% is neutral to alkaline, and a pH of 7.5 to 11 is particularly preferable. Further, the powder type is preferable from the viewpoint that the present copolymer can be premixed with calcium aluminate in advance and the trouble of separately charging or mixing at the time of construction can be reduced.
The pulverization of the present copolymer can be carried out by subjecting a liquid product to a drying treatment with a dryer such as a spray dryer.

As the carbonate according to the present invention, any of inorganic carbonates can be used, but alkali carbonates such as sodium carbonate, potassium carbonate, calcium carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate can be used. Preferably, any of its hydrated salt and anhydrous salt can be used.
Among these, it is preferable to use sodium carbonate because it is easily available. JIS K 1201, JIS K 8624, and JIS K 8625
It is possible to use sodium carbonate as specified in. The particle size of the carbonate is preferably as fine as possible so that it can be easily dissolved in water when mixed with calcium aluminate.
The mesh or less is preferable, and the mesh 200 or less is more preferable. The purity of the carbonate is not particularly limited,
Presently, it is possible to use industrially refined carbonates, and it is preferable to use those having a target carbonate purity of about 80% or more.

The boric acid according to the present invention is boric acid or its alkali salt. Here, boric acid is also known as boric acid, orthoboric acid, or orthoboric acid, and H ₃
It is also possible to use those represented by the chemical formula of BO ₃ and containing pyroboric acid, tetraboric acid, or metaboric acid. The method for producing boric acid is not particularly limited, but it is usually obtained by adding sulfuric acid to a raw ore of boric acid to thermally decompose it, liberating generated boric acid, separating and extracting, and then purifying.
The alkali salt of boric acid is, for example, a sodium salt or a potassium salt, of which the sodium salt is preferably used, and any of its hydrated compound and anhydrous compound can be used. The particle size of boric acid is preferably as small as possible so that it can be easily dissolved in water when mixed with calcium aluminate. Further, the purity of boric acid is not particularly limited, but it is possible to use boric acid which is currently industrially refined, and bo ₃ content in boric acid is about 80% or more. Use is preferred.

The carboxylic acids according to the present invention are used for extending the pot life and improving the fluidity during castable kneading, and are oxycarboxylic acids or their alkali salts, specifically citric acid. , Tartaric acid, succinic acid, lactic acid,
And gluconic acid or its alkali salt. Examples of alkali salts of carboxylic acids include sodium salt, potassium salt, calcium salt and the like. Of these, citric acid or its alkali salts, among them,
Use of sodium citrate or potassium citrate is preferable from the viewpoints of extending the pot life of the castable, obtaining an appropriate curing time, and improving the fluidity and strength development.
The particle size of the carboxylic acid is preferably as fine as possible so that it can be easily dissolved in water when mixed with calcium aluminate, preferably 100 mesh or less, more preferably 200 mesh or less. The purity of the carboxylic acids is not particularly limited, and it is possible to use industrially purified carboxylic acids at present, and it is preferable to use a carboxylic acid having a purity of about 80% or more as a target. Above all,
Use of citric acid with less than 0.05% sulfate as an impurity or its salt, or sodium citrate or potassium citrate with a pH of a 1% aqueous solution at 20 ° C in the range of 7 to 10 has a long working life. It is more preferable because it can be removed.

The mixing ratio of the above materials is 100% of the present copolymer.
Carbonate 10 to 100 parts by weight, boric acid 10 to 1 with respect to parts by weight
00 parts by weight and 10 to 200 parts by weight of carboxylic acids are preferred. Furthermore, 20 parts of carbonate is added to 100 parts by weight of this copolymer.
~ 50 parts by weight, boric acids 20 to 50 parts by weight, and carboxylic acids
15 to 100 parts by weight is more preferable. Outside of this range, when compounded with calcium aluminate, the pot life, curing time, fluidity, strength development, etc. are not balanced, and the pot life is shortened or the curing time is delayed, Tend to lack sex.

The amount of the mixture of the present copolymer, carbonate, boric acid, and carboxylic acid used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of calcium aluminate,
0.5 to 5 parts by weight is more preferable. If it exceeds 10 parts by weight, the tendency for retardation of curing becomes strong, and if it is less than 0.1 parts by weight, the pot life tends to be short and the fluidity tends to be poor.

The cement composition of the present invention can be used together with various cements such as Portland cement, and the cement composition of the present invention can be used alone as a cement.

Further, in order to obtain high strength in the intermediate temperature range when the cement composition of the present invention is used for applications requiring high fire resistance and high corrosion resistance, that is, in the vicinity of 700 to 1,200 ° C., It is preferable to further add α-alumina.

Here, α-alumina refers to aluminum hydroxide obtained by purifying bauxite by a Bayer process or the like and fired in a firing facility such as a rotary kiln. Alternatively, it is called calcined alumina or the like. The α-alumina α-alumina content is preferably 70% or more, more preferably 90% or more, and most preferably 95% or more because the firing strength at high temperature is excellent and the shrinkage at high temperature is small. And Al of α-alumina
_{The 2} O ₃ content is preferably 95% or more, more preferably 99% or more. The Na ₂ O content of α-alumina is preferably 1.0% or less, more preferably 0.5% or less. Furthermore, the specific surface area measured by the BET method by nitrogen gas adsorption of α- alumina preferably 0.1 to 100 m ² / g, more preferably ^{0.5~20m 2 / g, 2~10m 2 /} g it is most preferred. Here, the crushing of the alumina is such that the crushing is smaller than the particle size of the α crystal constituting the alumina particles, workability when the cement composition of the present invention is used, pot life, and securing of firing strength at high temperature, etc. From the viewpoint of.

As a method of blending α-alumina into the cement composition of the present invention, a method of mixing and pulverizing with a Nauta mixer, a pan mixer, a corn blender, etc., after weighing, ball mill, tube mill, vibration A method of mixing and pulverizing with a pulverizer such as a mill, roller mill, and tower mill, or after pulverizing the alumina of the present invention alone with a pulverizer, materials such as calcium aluminate pulverized to a predetermined particle size with a mixer are mixed. Methods and the like.

The blending amount of α-alumina is preferably 5 to 500 parts by weight, and more preferably 20 to 300 parts by weight, with respect to 100 parts by weight of calcium aluminate, since the curing strength and the drying strength are less likely to decrease. If it is less than 5 parts by weight, the firing strength at high temperature is insufficient and the effect of improving fire resistance is small, and if it exceeds 500 parts by weight, the curing strength and the dry strength tend to be lowered.

Furthermore, in the present invention, each of the above materials or a mixture of the respective materials is heated at a temperature of 100 to 300 ° C. for 30 minutes or more,
It is preferable to perform a treatment of drying or light baking for 60 minutes or more because the fluidity when blended with calcium aluminate is improved, and in particular, those treated at 150 to 200 ° C. have a long pot life. Further, the effect of obtaining an appropriate curing time and improving the fluidity and strength development is remarkable.

When gluconic acid or its salt is used as the carboxylic acid, gluconic acid or its salt is
Since there is a risk of rapid thermal decomposition near 0 ° C, it is preferable to add it to other materials afterwards. The blending ratio of gluconic acid or a salt thereof in this case is to be appropriately determined according to the type of calcium aluminate and the desired properties required, but usually 10 parts by weight or less relative to 100 parts by weight of calcium aluminate. Is preferred and 1 part by weight or less is more preferred. A large amount of gluconate added tends to delay the cure time when mixed with calcium aluminate.

The cement composition of the present invention comprises GC-MS,
It can be specified by instrumental analysis such as C ¹³ -NMR, HPLC, FT-IR, activation analysis and the like.

The method of mixing the respective raw materials constituting the present invention is not particularly specified, and the respective raw materials are blended so as to have a predetermined ratio, and a V blender, a corn blender, a Nauta mixer, a pan type mixer and an omni mixer. It is possible to carry out uniform mixing using a mixer such as, or, after mixing at a predetermined ratio, mix and pulverize with a pulverizer such as a vibration mill, a tube mill, and a ball mill.

Further, when used for refractory applications, it is further required to use various types of ultrafine powder such as silica fume and fine alumina having a particle size of about 3 μm or less, and alumina, magnesia, spinel, chamotte, bauxite, and brick dust. It is also effective to use an aggregate together, and in particular, it is preferable to use a basic aggregate such as magnesia or spinel and / or a refractory aggregate such as alumina or mullite.

Furthermore, it is possible to mix metal aluminum, organic fibers, aluminum lactate, etc. as an explosion proof material when the castable is cured and dried.

[0037]

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

Example 1 As an alumina source, specific surface area 8 m ² / g, Al ₂ O ₃ 99.6%, N
a ₂ O is 0.35%, α conversion rate is 96%, average particle diameter is 45 μm, α-alumina manufactured by Nippon Light Metal Co., Ltd., trade name “A12” is used, and commercially available quick lime is used as a calcia source. Blended so that the peak ratio of C ₁₂ A ₇ and CA in the specified value, and calcined in a siliconit electric furnace to produce calcium aluminate clinker, crushed with a batch type ball mill and a Blaine specific surface area of 6,000 cm ² A variety of calcium aluminates / g were produced. Various calcium aluminate 10
100 parts by weight of the sodium acrylate-sodium methacrylate copolymer of the present copolymer a, 30 parts by weight of sodium carbonate of carbonate α, 20 parts by weight of sodium borate of boric acid a, and 0 A mixture containing 20 parts by weight of sodium citrate as an acid was mixed as shown in Table 1 and mixed for 30 minutes with an omni mixer 10 manufactured by Chiyoda Giken Kogyo Co., Ltd. to prepare a cement composition. Each physical property of the produced cement composition was measured in a thermostatic chamber at 30 ° C. The results are also shown in Table 1.

<Measurement method> Fluidity: Using mortar described in JIS R 2521 prepared by kneading 200 parts by weight of Toyoura standard sand, 100 parts by weight of cement composition, and 60 parts by weight of water in a kneading pot for 3 minutes. , Leave it at 30 ° C for a predetermined time, knead for 30 seconds, measure the spread diameter after 15 taps with a flow table according to JIS R 2521, and measure the flow value after this predetermined time as fluidity. And Pot life: The prepared mortar was put in a plastic bag, and the time required until the mortar became soft without touching it was defined as the pot life. Curing time: A small amount of the prepared kneaded product was transferred to a polybeaker and measured with a platinum resistance thermometer and a dot recorder, and the time taken from water injection to the peak was taken as the curing time. Compressive strength: The prepared mortar was placed in a 4 × 4 × 16 cm mold and the compressive strength after curing for 24 hours was measured with a hydraulic pressure measuring machine. Mineral composition: measured by X-ray diffractometer "RAD-2B" manufactured by Rigaku Corporation. _{C 12 A 7 = 4.89Å, C} 3 A = 4.22Å, CA = 4.67Å, and measuring the diffraction intensity ratio of CA ₂ = 4.44Å.

<Materials used> Calcium aluminate A: CaO 30%, main mineral composition CA and C
₁₂ A ₇ , C ₁₂ A ₇ / CA Peak ratio 0.1 Calcium aluminate B: CaO 35%, main mineral composition CA and C
₁₂ A ₇ , C ₁₂ A ₇ / CA Peak ratio 0.3 Calcium aluminate C: 35% CaO, main mineral composition CA and C
₁₂ A ₇ , C ₁₂ A ₇ / CA Peak ratio 0.3 Calcium aluminate D: 35% CaO, main mineral composition CA and C
₁₂ A ₇ , C ₁₂ A ₇ / CA Peak ratio 0.5 Calcium aluminate E: CaO 35%, main mineral composition CA and C
₁₂ A ₇ , C ₁₂ A ₇ / CA Peak ratio 1.0 Calcium aluminate F: 35% CaO, main mineral composition CA and C
₁₂ A ₇ , C ₁₂ A ₇ / CA Peak ratio 3.0 Calcium aluminate G: CaO 35%, main mineral composition CA and C
₁₂ A ₇ , C ₁₂ A ₇ / CA Peak ratio 5.0 Calcium aluminate H: CaO 35%, main mineral composition CA and C
₁₂ A ₇ , C ₁₂ A ₇ / CA peak ratio 10 Copolymer a: sodium acrylate-sodium methacrylate copolymer, manufactured by Nippon Pure Chemical Co., Ltd., 40% slurry viscosity is 400 to 500 cps / 25 ° C, 40% concentration slurry pH is 9.
0/25 ° C, sodium acrylate / sodium methacrylate weight ratio 8/2 Carbonate α: Sodium carbonate, Ishizu Pharmaceutical Co., Ltd. reagent first class boric acid a: Sodium borate, Ishizu Pharmaceutical Co., Ltd. reagent first class carboxylic acid: Sodium citrate, Ishizu Pharmaceutical Co. reagent 1st grade

[0041]

[Table 1]

As is clear from Table 1, even when calcium aluminates having different C ₁₂ A ₇ / CA peak ratios are blended, the cement composition of the present invention can secure a long pot life and an appropriate curing time. , Shows excellent fluidity and high strength development.

Example 2 100 parts by weight of this copolymer, sodium borate 2 of boric acid group a
Same as Example 1 except that 0 part by weight, 20 parts by weight of carboxylic acid sodium citrate, and 0.8 parts by weight of a mixture containing the carbonate shown in Table 2 were added to 100 parts by weight of calcium aluminate B. Went to. The results are also shown in Table 2.

<Materials used> This copolymer b: sodium acrylate-sodium methacrylate copolymer, manufactured by Nippon Pure Chemical Co., Ltd., 40% slurry viscosity is 1,000 to 1,100 cps / 25 ° C, 40% slurry pH
Is 6.7 / 25 ° C., sodium acrylate / sodium methacrylate weight ratio is 5/5 Carbonate β: potassium carbonate, Ishizu Pharmaceutical Co., Ltd. reagent grade 1 Carbonate γ: sodium hydrogen carbonate, Ishizu Pharmaceutical Co., Ltd. grade 1

[0045]

[Table 2]

As is clear from Table 2, the cement composition of the present invention has a long pot life and an appropriate setting time, and exhibits excellent fluidity and high strength development.

Example 3 100 parts by weight of the present copolymer a, sodium carbonate of carbonate α 30
Example 2 was carried out in the same manner as in Example 2 except that a mixture containing 1 part by weight, 20 parts by weight of carboxylic acid sodium citrate, and boric acid shown in Table 3 was used. The results are also shown in Table 3.

<Materials used> Boric acids b: Potassium borate, first grade reagent made by Ishizu Pharmaceutical Co., Ltd. Boric acids c: Boric acid, first grade reagent made by Ishizu Pharmaceutical Co., Ltd.

[0049]

[Table 3]

As is clear from Table 3, the cement composition of the present invention has a long pot life and an appropriate curing time, and exhibits excellent fluidity and high strength development.

Example 4 100 parts by weight of this copolymer a, sodium carbonate of carbonate α 30
Example 2 was carried out in the same manner as in Example 2 except that a mixture prepared by adding 20 parts by weight of sodium borate of boric acid a and carboxylic acids shown in Table 4 was used. The results are also shown in Table 4.

<Materials used> Carboxylic acids: potassium citrate, first grade reagent made by Ishizu Pharmaceutical Co., Ltd. Carboxylic acids :: citric acid, first grade reagent made by Ishizu Pharmaceutical Co., Ltd.

[0053]

[Table 4]

As is clear from Table 4, the cement composition of the present invention has a long pot life and an appropriate setting time, exhibits excellent fluidity and high strength development, and is excellent in the past. It has characteristics.

Example 5 100 parts by weight of the present copolymer a, sodium carbonate of carbonate α 30
Except that a mixture containing 20 parts by weight of sodium borate of boric acid and 20 parts by weight of sodium citrate of carboxylic acid is added as shown in Table 5 to 100 parts by weight of calcium aluminate B. Was performed in the same manner as in Example 1. The results are also shown in Table 5.

[0056]

[Table 5]

As is clear from Table 5, the cement composition of the present invention has a long pot life and an appropriate curing time, exhibits excellent fluidity and high strength development, and has excellent properties that have never been obtained before. have.

Example 5 For 50 parts by weight of α-alumina used in Example 1 and 50 parts by weight of calcium aluminate B, 100 parts by weight in total,
1.6 parts by weight of the mixture used in Example 1 was blended and mixed and pulverized with a Kawasaki Heavy Industries, Ltd. type 15 vibration mill to a predetermined particle size to produce the cement composition of the present invention, and its physical properties were measured.
The results are also shown in Table 6. The physical properties were measured in the same manner as in Example 2 except that the following was carried out.

<Measurement method> Blaine specific surface area: According to the measurement method described in JIS R 2521. Average particle diameter: Measured with a laser diffraction particle size distribution analyzer “SALD1000 A range” manufactured by Shimadzu Corporation. Baking strength: 20 parts by weight of cement composition, as an aggregate, 24 parts by weight of particle size 3.36 to 1.68 mm of sintered alumina manufactured by Showa Denko KK,
16 parts by weight of 1.68 to 0.71 mm, 20 parts by weight of 0.71 to 0.297 mm,
20 parts by weight under 0.297 mm and 8 parts by weight of water, and kneaded with a mortar mixer for 5 minutes to obtain 4 × 4 × 16.
It was packed in a cm formwork, cured for 24 hours, and then deframed. further,
A test piece obtained by drying at 110 ° C. for 20 hours and then at 400 ° C. for 3 hours was fired at 1,000 ° C. in a silicon knit type electric furnace, and then gradually cooled to room temperature to measure the compressive strength.

[0060]

[Table 6]

As is apparent from Table 6, the cement composition of the present invention has a long pot life and an appropriate curing time, exhibits excellent fluidity and high strength development, and is excellent in the past. It has characteristics.

[0062]

EFFECTS OF THE INVENTION As is clear from the above examples, the cement composition of the present invention, which cannot be achieved by conventional products, has a function originally required for alumina cement when compounded in castable, In particular, the pot life is long, and the functions such as appropriate curing time, fluidity and strength development can be sufficiently satisfied. In addition, it has a high fluidity and a pot life extension effect that were not available in conventional products.

The cement composition of the present invention can be widely used not only in the field of refractory materials such as refractory concrete but also in the field of civil engineering / construction materials.

Since it is excellent in fire resistance and high temperature strength,
Blended with refractory aggregates such as alumina, magnesia, spinel, chamotte, bauxite, silicon carbide, fused silica, zircon, and brick scraps, as a refractory such as refractory concrete or precast blocks, or sand, gravel, and crushed stone. It can be used as a civil engineering / building material such as concrete or mortar mixed with various polymer emulsions or latices.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // (C04B 28/06 24:26 E 22:10 22:08 Z 24:04) 103: 10 103: 20

Claims (1)

[Claims] 1. Calcium aluminate, acrylic acid-
A cement composition containing a methacrylic acid copolymer, a carbonate, boric acids, and carboxylic acids.