JP2002321952A - Cement admixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize ashes mostly discarded which have pozzolan activity like an incineration ash of pulp sludge or a fly ash or the like as cement admixtures. SOLUTION: Wet pulverization of ashes which have pozzolan activity like an incineration ash of pulp sludge or a fly ash or the like under an existence of an organic dispersant in an aqueous medium makes the ashes into ultra fine powders of 3 μm or less in mean particle diameter like slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement admixture, and more particularly, to a slurry obtained by wet-milling ashes having pozzolanic activity, such as pulp sludge incinerated ash and fly ash. It relates to a cement admixture.

[0002]

2. Description of the Related Art Fly ash discharged from a coal-fired boiler is increasing year by year, and its effective use method is being actively studied. There is a limit due to non-uniformity, etc., and only a part of it is used as a cement admixture, and most of it is currently landfilled. In addition, the incineration ash of pulp sludge generated in the pulp manufacturing process or papermaking process has reached 500,000 tons annually in Japan alone, but only a small part of it is used as a soil conditioner or as a filler for purification systems. The rest is discarded, and at present it is regarded as a problem in terms of land for disposal (landfill) and environmental conservation.

[0003] Also, the fly ash and pulp sludge incineration ash contains both many Si0 ₂ component itself gradually Ca (OH) ₂ and room temperature produced by the hydration of cement is no hydraulic It is known that it has the property of forming insoluble calcium silicate, that is, it has pozzolanic activity, and it is important to discard most of such ashes having pozzolanic activity without utilizing them.
It is not preferable from the viewpoint of resource saving.

Accordingly, an object of the present invention is to provide ashes having a pozzolanic activity, such as pulp sludge incinerated ash and fly ash, which are mostly discarded.
It is intended to be able to be effectively used as a cement admixture.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that ashes having pozzolanic activity such as pulp sludge incinerated ash and fly ash by a specific wet grinding method. Can be easily pulverized, and the slurry-like ultrafine powder obtained by this wet pulverization is easy to mix when used as a cement admixture, without lowering the strength of mortar or concrete, Rather, they found that the physical properties such as strength were to be improved, and completed the present invention.

That is, the cement admixture according to the present invention comprises:
Ashes having pozzolan activity were wet-pulverized in an aqueous medium in the presence of an organic dispersant to obtain a slurry-like ultrafine powder having an average particle size of 3 μm or less.

Here, the ash having the pozzolanic activity preferably contains a silica content of 30% by weight or more in terms of SiO ₂ . This is because the pozzolanic activity is insufficient when the silica content is less than 30% by weight in terms of SiO ₂ .

The organic dispersant used in the present invention may be any one of a water-soluble cationic surfactant, a water-soluble anionic surfactant, and a water-soluble nonionic surfactant, or a mixture thereof. A combination of two or more can be used, and the weight ratio of the ash to the aqueous medium is 70:30 to 30:70, preferably 60:40 to 4
An aqueous medium was added to the ash so that the ratio was in the range of 0:60, and the ash 1 was added thereto with the above-mentioned organic dispersant as a solid content.
0.01 to 5 parts by weight per 100 parts by weight, preferably 0.1 to 5 parts by weight.
The wet pulverization is carried out by an ordinary method by adding 01 to 0.7 parts by weight.

In the present invention, it is essential that the ash obtained by the wet pulverization has an average particle size of 3 μm or less. This is because when the average particle size exceeds 3 μm, a sufficient microfiller effect cannot be obtained.

[0010] The above-mentioned cement admixture according to the present invention is in the form of a slurry obtained by wet pulverization, so that it does not generate dust during handling and can be easily mixed when producing various cement products. At the same time, since it is an ultrafine powder having an average particle diameter of 3 μm or less, it plays a role as a so-called microfiller, and the silica component having pozzolanic activity contained in the ash is further pulverized to become more reactive. By mixing this, it is possible to improve physical properties such as strength without causing a decrease in strength in various cement products such as mortar or concrete, and it is possible to improve cement mixing, which can be a substitute for expensive silica fume. Pulp sludge incineration ash and fly-up, which have been largely discarded in the past. The ash such as Interview, it is possible to use as aggressively resources. In addition, the cement admixture referred to in the present invention refers to a material that is admixed when manufacturing various cement products such as mortar, concrete, and building boards.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail. Ashes targeted by the present invention include pulp sludge incineration ash, fly ash, sewage sludge incineration ash, municipal waste incineration ash, and the like. Since these ashes have different particle diameters and compositions depending on their discharge factories and the like, they have an average particle diameter of about 3 to 70 μm, a composition of 30 to 60% by weight of SiO ₂ ,
l ₂ O ₃ is 5-30 wt%, ash such that CaO is contained 5 to 30% by weight is subject of the present invention. However, as the ash used in the present invention, the content of SiO ₂ is preferably 40% by weight or more, and it is desired that the ash is present in a large amount and its composition is not largely varied. Incinerated ash and fly ash are preferred.

In the present invention, the ash as described above is wet-pulverized. Specifically, the weight ratio of ash / aqueous medium is 70/30 to 30/70, preferably 60/40.
An aqueous medium is added to the ash so as to be in a range of from 40 to 60/60, and an organic dispersant is added thereto as a solid content in an amount of 0.01 to 5 parts by weight, preferably 0.01 to 0.5 part by weight, per 100 parts by weight of the ash. 7 parts by weight are added and wet-pulverized by an ordinary method, or an aqueous medium obtained by previously dissolving an organic dispersant having an amount in the above range is mixed with the ash, and wet-pulverized by an ordinary method to obtain an average. The ash is pulverized into ultrafine powder having a particle diameter of 3 μm or less, preferably 0.3 to 1 μm.

Here, if the mixing ratio of the ash to the aqueous medium is less than 30/70, precipitation of the ash is liable to occur, making it impossible to maintain a uniform concentration. Conversely, if the ratio exceeds 70/30, the viscosity becomes high, and the crushing efficiency is deteriorated and blockage in the pipe is liable to occur. Further, the addition amount of the organic dispersant is 0.00.0 parts by weight per 100 parts by weight of the ash.
If the amount is less than 1 part by weight, the effect of dispersing the ash in the aqueous medium cannot be obtained, and uniform pulverization becomes difficult.
Conversely, if the dispersant is added in an amount exceeding 5 parts by weight, it is not preferable because the ash and the aqueous medium are separated.

As the aqueous medium, tap water is preferably used, but purified water, recovered water and the like may be used. In that case, it is preferable to adjust the pH to about 6 to 10.
Examples of the organic dispersant include a water-soluble cationic surfactant, a water-soluble anionic surfactant, and a water-soluble nonionic surfactant. These dispersants can be used alone or in combination. A combination of the above can also be used.

The water-soluble cationic surfactant used as the organic dispersant includes primary, secondary and tertiary amine salt type cationic low molecular or high molecular surfactants and quaternary ammonium salt type cationic low surfactant. Molecular or polymeric surfactants.

Examples of the primary to tertiary amine salt type low molecular surfactants include higher alkylamine salts, higher alkylamine ethylene oxide adducts, higher alkylamine ethylene oxide / propylene oxide adducts, solomine A type amine salts, Sapamine A-type amine salts, Arcovelle A-type amine salts, imidazoline-type amine salts and the like. Examples of the primary to tertiary amine salt type polymer surfactants include polyethylene imine, polyalkylene polyamine salts, polyamine / dicyandiamide condensed salts, and polydiallylamine salts. Examples of the quaternary ammonium salt type low-molecular surfactant include higher alkyltrimethylammonium salts, alkyldimethylbenzylammonium salts, sapamin-type quaternary ammonium salts, imidazoline-type quaternary ammonium salts, and alkylpyridium salts. Can be Examples of the quaternary ammonium salt type polymer surfactant include polystyrene methylaminotrimethylammonium salt, polydiallyldimethylammonium salt, trimethylaminoethyl (meth) acrylate ammonium salt, and polyN-alkylpyridine salt.

Of the above-mentioned water-soluble cationic surfactants, an amine salt-type polymer surfactant or a quaternary ammonium salt-type polymer surfactant is preferable in order to obtain a high-concentration slurry during wet pulverization. Particularly preferred are salts of diallylamine alone or copolymers with vinyl compounds and polydiallyldimethylammonium salts. These molecular weights are not particularly limited, but are preferably 1,000 to 15,000, and more preferably 5,000.
~ 8000.

The water-soluble anionic surfactant used as the organic dispersant includes a low-molecular or high-molecular surfactant having a carboxylate, sulfate, sulfonate or phosphate salt as a functional group. Is mentioned.

Examples of the low molecular weight carboxylate include higher fatty acid salts such as sodium laurate, sodium stearate and sodium oleate, higher alcohol polyethylene oxide ether acetate, and perfluoroalkyl carboxylate. As the acid salt, for example, a polyacrylic acid salt, a copolymer of at least two or more of carboxylic acid monomers such as a salt of a polyacrylic acid-maleic acid copolymer or a salt thereof, a vinyl compound and a carboxylic acid A copolymer with a system monomer or a salt thereof, carboxymethyl cellulose, and the like can be given. Examples of the low molecular sulfate ester salt include higher alcohol polyethylene oxide sulfate ester salt, sulfated oil, sulfated fatty acid ester, sulfated fatty acid, sulfated olefin, and alkylphenol polyethylene oxide sulfate salt. Examples of the low molecular sulfonate include alkylbenzene sulfonate, α-
Olefin sulfonate, alkane polysulfonate,
Perfluoroalkyl sulfonates, Igephone T type and aerosol type, etc., and as the polymer sulfonate, formalin condensate of naphthalene sulfonate, polystyrene sulfonate, polyvinyl sulfonate, polyaryl sulfonate and Salts of a copolymer of acrylamide and acrylamidopropanesulfonic acid are exemplified. Examples of the copolymerizable polymer surfactant include a copolymer composed of a carboxylic acid monomer and a sulfonic acid monomer or a salt thereof. Examples of the low molecular phosphate ester salt include a higher alcohol monophosphate ester salt, a higher alcohol polyethylene oxide phosphate ester salt and an alkylphenol polyethylene oxide phosphate ester salt.

Among these anionic surfactants, in order to obtain a high-concentration slurry at the time of wet pulverization, a polymer type surfactant is preferable, but polyacrylic acid or a salt thereof, and polyacrylic acid are particularly preferable. A carboxylic acid monomer such as a maleic acid copolymer or a salt thereof alone or a copolymer comprising at least two or more thereof or a salt thereof may be mentioned. These molecular weights are not particularly limited, but are preferably 1,000 to 100,000, more preferably 50 to 100,000.
00 to 50,000.

The water-soluble surfactant used as the organic dispersant includes polyethylene glycol type and polyhydric alcohol type nonionic surfactants.

Examples of the polyethylene glycol type include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, fatty acid amide ethylene oxide adducts, and polypropylene glycol ethylene oxide. Adducts and polyether modified silicones. Examples of the polyhydric alcohol include fatty acid esters of glycerol, fatty acid esters of pentaerythritol, fatty acid esters of sorbitol and sorbitan,
Fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid esters of polyglycerin or ethylene oxide adducts thereof, and fatty acid amides of alkanolamines.
C), hydroxyethyl cellulose (HEC), polyvinyl alcohol (PVA), polyalkylene oxide vinyl ether compound, polyhydroxylalkyl (meth) acrylate, and the like.

The wet pulverization using the aqueous medium and the organic dispersant may be a batch type or a continuous type, and it is preferable to use a mill using a pulverizing medium such as a sand mill, an attritor, a ball mill or the like. . Among these pulverizers, a wet media stirring mill is particularly preferable. This wet medium stirring mill is an apparatus that moves a medium by vibrating the mill and applies a shearing force, an impact force, a frictional force, and the like to a material to be ground to pulverize the material.

As described above, the ashes having pozzolan activity are wet-pulverized in an aqueous medium in the presence of an organic dispersant, whereby the ashes can be micronized with lower energy compared to dry pulverization. Since the generation of dust in the inside is small, the working environment is not deteriorated. Further, since the wet pulverization is performed in the presence of the organic dispersant, a slurry-like ultrafine powder having a low viscosity even at a high concentration can be obtained by the action of the organic dispersant.

Since the obtained ultrafine powder is in a slurry state as described above, there is no generation of dust at the time of handling, it can be easily mixed when manufacturing various cement products, and the average particle size is 3 μm or less. Since it is an ultrafine powder, it plays a role as a so-called microfiller, and the silica component having pozzolan activity contained in the ash becomes more highly reactive by being ultrafine powdered, and is mixed. By doing so, it is possible to improve physical properties such as strength without causing a decrease in strength in various cement products such as mortar or concrete, and it replaces expensive silica fume conventionally used for the purpose of improving strength and fluidity. It becomes a cement admixture that can be a product.

The cement admixture according to the present invention is preferably added at a ratio of 40% by weight or less, preferably 10 to 20% by weight, based on the solid content, based on the cement.
This is not preferable because if the amount exceeds 40% by weight, calcium hydroxide becomes insufficient and it becomes difficult to obtain a sufficient pozzolanic reaction.

[0027]

EXAMPLES [Pulverization] Example 1 42.9% by weight of SiO ₂ , 28.2% by weight of Al ₂ O ₃ ,
CaO 17.6% by weight, Fe ₂ O ₃ 0.7% by weight, Mg
O 3.3% by weight and an average particle size of 13.2 μm (= D
₅₀ ) The weight ratio of pulp sludge incinerated ash to water is 60 /
Water was added to make the pulp sludge incineration ash 10
Anionic surfactant [SN-2X6301 (specially modified polyacrylic acid salt) manufactured by San Nopco Co., Ltd.] is added in an amount of 1.5 parts by weight as an active ingredient per 0 parts by weight, and a table-type medium stirring mill [Mitsui Miike Kakoki Co. Company: Attritor MA-1SE], a zircon ball having a diameter of 0.5 to 2.0 mm, a filling rate of 20 to 30% by volume, and a peripheral speed of 15
Wet pulverization at 0 to 200 revolutions / minute, average particle size 2.2 μm
(= D ₅₀ ) slurry-like ultrafine powder was obtained.

Example 2 51.5% by weight of SiO _2, 24.2% by weight of Al ₂ O ₃ ,
10.5% by weight of CaO, 4.8% by weight of Fe ₂ O ₃ , Mg
O 2.3% by weight and an average particle size of 16.5 μm (= D
₅₀ ) Water was added so that the weight ratio of fly ash to water was 70/30, and anionic surfactant [manufactured by San Nopco Co .: SN: 100 parts by weight of fly ash]
-2X6301 (specially modified polyacrylic acid salt)] in terms of the effective ingredient, and using a table-type medium stirring mill similar to the above, using a silica sand having a diameter of 0.5 to 2.0 mm, and filling rate. 20-30% by volume, peripheral speed 150-20
Wet pulverization at 0 revolutions / minute, average particle size 2.0 μm (= D
₅₀ ) A slurry-like ultrafine powder was obtained.

[Properties as Cement Admixture] Examples 3 to 5 and Comparative Examples 1 to 4 Slurry ultrafine powder of pulp sludge incinerated ash obtained in Example 1 was converted into cement in terms of solid content [Taikai Cement Co., Ltd.] Made: ordinary Portland cement]
wt.% (Example 3), fly ash slurry obtained in Example 2 was replaced with 10% by weight of the cement in terms of solid content (Example 4), and The slurry-like ultrafine powder of pulp sludge incineration ash obtained in Example 1 and silica fume [manufactured by EFFACO, average particle size: 2.29 μm] were converted to a solid content of 50: 5.
The mixture mixed at 0 is divided into 10 w
t /% substitution (Example 5)
(Sand / powder ratio) = 1, W / P (water / powder ratio) = 22.5
% Of sand (land sand from Ogasawara) and water, and an appropriate amount of a high-performance AE water reducer [manufactured by NMB Corporation: Leobuild S
P8S-X2], and kneaded.
A cement composition of 0 ± 10 mm was obtained.

In addition, no admixture was added to the above cement (Comparative Example 1), and the pulp sludge incineration ash before pulverization used in Example 1 was replaced by 10 wt% in the above cement. (Comparative Example 2), the above-mentioned cement in which the fly ash before pulverization used in Example 2 was replaced by 10% by weight in the inner part (Comparative Example 3), and the above-mentioned silica fume was further inwardly divided into the above-mentioned cement. 10w
Also for the t-substituted (Comparative Example 4), sand and water and an appropriate amount of a high-performance AE water reducing agent were added and kneaded at S / P = 1 and W / P = 22.5% in the same manner as described above, and kneaded. 0 stroke flow is 2
A cement composition of 30 ± 10 mm was obtained.

Table 1 shows the amount of the high-performance AE water reducing agent required to obtain a cement composition having a zero-strike flow of 230 ± 10 mm.

[0032]

[Table 1]

The flexural strength and compressive strength of the cured product obtained by steam curing each of the above cement compositions at 60 ° C. for 24 hours were measured in accordance with the test method specified in JIS.
In addition, the above cement composition was treated at 20 ° C. for 7 days, and 28 days.
The flexural strength and compressive strength of the cured product obtained by curing in water each day were measured in accordance with the test method specified in JIS. Table 2 shows the measurement results. When silica fume alone was used as a cement admixture (Comparative Example 4)
Table 3 shows the values of other measured values when the above measured value was set to 100. FIGS. 1 to 3 show graphs of the values.

[0034]

[Table 2]

[Table 3]

Examples 6, 7 and Comparative Example 5 The slurried ultrafine pulp sludge ash obtained in Example 1 was divided into the above cement in terms of solid content by 10%.
wt.% (Example 6), the fly ash slurry obtained in Example 2 was replaced by 10 wt% in terms of solid content with respect to the cement in terms of solid content (Example 7), and The above-mentioned sand was added at S / P = 1 for each of the silica fumes replaced with 10% by weight of the above cement relative to the cement (Comparative Example 5), and P × 4.0% by weight.
AE water reducing agent was added at a ratio of 0.1%, and water was further added at an appropriate water ratio (= W / P) and kneaded.
A cement composition of 0 ± 10 mm was obtained.

Table 4 shows the water ratio (= W / P) required to obtain a cement composition having a zero-strike flow of 230 ± 10 mm.

[0037]

[Table 4]

The cured product obtained by steam curing each of the above cement compositions at 60 ° C. for 24 hours, and the bending strength of the cured product obtained by curing in water at 20 ° C. for 7 days and 28 days, respectively.
And the compressive strength were measured in the same manner as described above in accordance with the test method specified in JIS. Table 5 shows the measurement results. Further, when the above measured value was 100 when silica fume alone was used as a cement admixture (Comparative Example 5),
Table 6 shows other measured values. 4 to 6 show graphs of the values.

[0039]

[Table 5]

[Table 6]

From the above Examples and Comparative Examples, it is recognized that the cement admixture according to the present invention has a water reducing effect and a strength improving effect equal to or higher than that of silica fume, and is used as a substitute for expensive silica fume. It turned out to be something that could be done.

[0041]

According to the present invention described above, the pozzolanic activity of pulp sludge incinerated ash and fly ash, which are regarded as problems in terms of land disposal (landfill), environmental protection, and resource saving, is considered. It is possible to actively utilize the ash that is possessed. That is, since the cement admixture according to the present invention is obtained by converting ashes having a pozzolanic activity such as pulp sludge incineration ash and fly ash into ultrafine powder in a slurry state, dust is not generated at the time of handling and the cement admixture is easily formed into cement. And also plays a role as a so-called microfiller, and the silica component having pozzolanic activity contained in the ash becomes more highly reactive by being micronized, and by mixing with cement, It can improve the fluidity and strength of mortar or concrete, and can be used as a cement admixture that can replace expensive silica fume that has been used for the purpose of improving strength and fluidity. it can.

[Brief description of the drawings]

FIG. 1 is a graph comparing flexural strength and compressive strength of cured products obtained by steam curing each of the cement compositions of Examples 3 to 5 and Comparative Examples 1 to 4 at 60 ° C. for 24 hours.

FIG. 2 is a graph comparing flexural strength and compressive strength of a cured product obtained by curing each of the cement compositions of Examples 3 to 5 and Comparative Examples 1 to 4 at 20 ° C. for 7 days in water.

FIG. 3 is a graph comparing the flexural strength and the compressive strength of a cured product obtained by curing each of the cement compositions of Examples 3 to 5 and Comparative Examples 1 to 4 at 20 ° C. for 28 days in water.

FIG. 4 is a graph comparing flexural strength and compressive strength of a cured product obtained by steam curing each of the cement compositions of Examples 6, 7 and Comparative Example 5 at 60 ° C. for 24 hours.

FIG. 5 is a graph comparing the flexural strength and the compressive strength of a cured product obtained by curing each of the cement compositions of Examples 6, 7 and Comparative Example 5 in water at 20 ° C. for 7 days.

FIG. 6 is a graph comparing flexural strength and compressive strength of a cured product obtained by curing each of the cement compositions of Examples 6, 7 and Comparative Example 5 in water at 20 ° C. for 28 days.

Claims (5)

[Claims] 1. A cement admixture, wherein ashes having a pozzolanic activity are wet-pulverized in an aqueous medium in the presence of an organic dispersant to obtain a slurry-like ultrafine powder having an average particle size of 3 μm or less. . 2. The ash according to claim 1, wherein said ash compound is made of SiO ₂
The cement admixture according to claim 1, wherein the cement admixture contains 30% by weight or more in terms of conversion. 3. The cement admixture according to claim 1, wherein the ash is incinerated pulp sludge ash or fly ash. 4. The organic dispersant is one of a water-soluble cationic surfactant, a water-soluble anionic surfactant, and a water-soluble nonionic surfactant, or a combination of two or more thereof. The cement admixture according to claim 1, 2 or 3, wherein 5. An aqueous medium is added to the ash so that the weight ratio of the ash to the aqueous medium is in the range of 70:30 to 30:70, and the organic dispersant is used as a solid component to make 100 parts by weight of the ash. 0.01 to 5 parts by weight per addition,
The cement admixture according to claim 1, 2, 3 or 4, wherein the cement admixture is wet-ground.