JPH08277152A - Curable inorganic composition - Google Patents

Abstract

PURPOSE: To obtain a curable inorganic composition capable of controlling the pot life, excellent in workability and providing an inorganic cured body having a high strength and excellent in appearance. CONSTITUTION: This composition contains 100 pts.wt. of reactive inorganic powder composed of 20-98 pts.wt. fly ash and 2-80 pts.wt. kaolin powder obtained by applying mechanical energy having 0.5-30.0kwh/kg to kaolin, 3-300 pts.wt. silicic acid alkali metal salt and 10-300 pts.wt. water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable inorganic composition which can be suitably used as a raw material for producing an inorganic cured product used in civil engineering, building materials and the like.

[0002]

2. Description of the Related Art Conventionally, various curable inorganic compositions which are cured by heat in the presence of alkali have already been proposed. For example, in Japanese Unexamined Patent Publication (Kokai) No. 4-59648, ash of a dust collector generated during the production of an aqueous solution of an alkali metal silicate and metakaolin, corundum or mullite, an alkali-reactive solid component such as fly ash and a filler, an organic bentonite It is proposed that a curable inorganic composition obtained by mixing an admixture is used to produce a cured inorganic material useful for building materials. In addition, JP-A-4-61
No. 38 discloses that a curable inorganic composition obtained by kneading an alkali metal silicate aqueous solution, the above alkali-reactive solid component and a filler is injected into a mold and cured by heating to produce an inorganic cured product. is suggesting.

[0003]

However, the inventors of the present invention have examined kaolin and fly ash that can be supplied in large amounts and at low cost among the alkali-reactive solid components shown above. There is a problem that because it has high crystallinity, it hardly reacts with alkali and an inorganic hardened body cannot be obtained.In the case of fly ash, the reactivity varies depending on the power plant that produces it, and the reaction rate is It turned out that there was a problem that it was very slow and the strength was low.

In order to solve the above problems, the inventors of the present invention have previously proposed a method of applying mechanical energy to kaolin used as a reactive solid component in advance. That is, in this method, mechanical energy is applied to kaolin to modify crystalline kaolin into amorphous kaolin powder and improve reactivity with alkali.

However, the kaolin powder obtained by this method is
As mentioned above, the reactivity with alkali is improved and the reaction rate becomes very fast, but on the other hand, if the composition mixing work is not done quickly, the composition is cured before being molded into a desired shape. That is, there is a problem that the pot life (usable time) is short. In view of such circumstances, the present invention provides a curable inorganic composition capable of obtaining an inorganic cured product having a controllable pot life and excellent workability as well as high strength and excellent appearance. Is intended.

[0006]

In order to achieve such an object, the curable inorganic composition of the present invention contains 20 to 98 parts by weight of fly ash and 0.5 k of kaolin.
100 parts by weight of reactive inorganic powder consisting of 2 to 80 parts by weight of kaolin powder obtained by applying mechanical energy of wh / kg to 30.0 kwh / kg, and 3 to 300 parts by weight of alkali metal silicate, It was configured to include 10 to 300 parts by weight of water.

In the above-mentioned structure, as the fly ash, for example, fine ash particles collected by a dust collector from a pulverized coal combustion boiler, which are defined in JIS A 6201, are pulverized or classified into finer particles. The thing and what baked this particle | grain at 400-1000 degreeC can be used. Kaolin refers to a 1: 1 layered silicate containing 50% by weight or more of a kaolin mineral represented by a chemical formula of Al ₂ Si ₂ O ₅ (OH) ₄ , specifically, kaolinite, dickite, Examples include kaolin minerals such as nacrite and halloysite containing water molecules between layers of kaolin minerals.

The kaolin used in the present invention is generally contained in clay such as clay minerals (mica, talc, smectite, allophane, imogolite, etc.), α-quartz and other silica minerals, feldspar, zeolite, etc. in addition to the above kaolin minerals. The mineral may be included. If the content of the kaolin mineral in kaolin is less than 50% by weight, it is difficult to make it excellent in reactivity with the hydraulic inorganic substance.

Further, kaolin is not particularly limited,
From the viewpoint of effective use of mechanical energy, the average particle size is preferably 0.1 μm to 500 μm, more preferably 0.1 μm to 100 μm.
To apply mechanical energy means to apply compressive force, shearing force, impact force, etc. to the raw material kaolin, and specifically, a crusher generally used for the purpose of crushing, for example, a crushing mechanism. Uses a ball media mill (ball mill, vibration mill, planetary mill, media agitation mill, etc.) that combines impact, friction, compression, shear, etc., roller mill, mortar, jet crusher whose mainstream is impact and grinding. Although this is possible, a ball medium type mill capable of mechanically effectively imparting mechanical energy to kaolin is preferable.

When mechanical energy is applied to kaolin by using a crusher, alcohols such as methyl alcohol or ethanol / amine such as triethanolamine used for crushing cement clinker, silica sand, limestone, etc. It is also possible to use a liquid-based grinding aid centering on a class of compounds, a solid-based grinding aid such as sodium / calcium stearate, or a gas-based grinding aid such as acetone vapor.

The mechanical energy acting on kaolin is limited to 0.5 kwh / kg or more and 30 kwh / kg or less. That is, the mechanical energy is 0.5 kwh
If it is less than 100 kg / kg, the crystal structure is not sufficiently modified, so that reactivity with the hydraulic inorganic substance can hardly be imparted, and if the mechanical energy is more than 30 kwh / kg, the load on the crushing device is large and the medium is used as a medium. There are problems such as severe wear of balls and containers, contamination of treated clay (contamination), and excessive cost. The mechanical energy shown above is expressed per unit weight of kaolin which processes the electric power supplied to the crushing device when the crushing device is operated with the above kaolin added.

In 100 parts by weight of the reactive inorganic powder,
20 to 98 parts by weight of fly ash, 0.5 kwh / k
The reason why the kaolin to which mechanical energy of g to 30.0 kwh / kg is applied is 2 to 80 parts by weight is that the reaction rate becomes slow when the fly ash content is more than 98 parts by weight, and mechanical energy is applied. Kaolin was made 8
This is because if the amount is more than 0 parts by weight, the pot life becomes extremely short, which may cause a problem in workability.

Alkali metal silicates include M ₂ O.n
Examples thereof include those represented by SiO ₂ (M = Li, K, Na, n is 0 and a positive real number), and n is preferably 8 or less. That is, when n exceeds 8, the aqueous alkali metal silicate solution is likely to cause gelation, and the viscosity rapidly increases due to gelation, which may make it difficult to mix with the powder.

The alkali metal silicate may be used alone or as a mixture of plural salts of different alkali metals. If the amount of the alkali metal silicate added is too large or too small, the curability of the resulting curable inorganic composition will be insufficient, so the amount will be 3 with respect to 100 parts by weight of the reactive inorganic powder. ˜300 parts by weight is preferred.

If the amount of water added is too large, the strength of the inorganic molded body obtained by curing the curable inorganic composition will be reduced, and if it is too small, molding of the curable inorganic composition will be difficult. Therefore, 3 to 300 parts by weight is preferable with respect to 100 parts by weight of the reactive inorganic powder. The alkali metal silicate is preferably added as an aqueous solution in order to improve the dispersibility of the alkali metal silicate. When added as an aqueous solution, the concentration of the aqueous solution is not particularly limited,
If the concentration is too high, the viscosity of the curable inorganic composition obtained will be high, and molding may be difficult. If the concentration is too low, the curable inorganic composition will not be cured. % By weight is preferred, 30-60% by weight
Is more preferable.

When the alkali metal silicate is used in the form of an aqueous solution, the alkali metal silicate may be dissolved in water as it is. However, the aqueous solution of the alkali metal hydroxide contains SiO ₂ components such as silica sand and silica stone powder. What melt | dissolved so that n might become predetermined amount may be used. Furthermore, reinforcing fibers, inorganic fillers, lightweight aggregates, etc. can be added to the curable inorganic composition of the present invention, if necessary.

As the reinforcing fiber, any fiber can be used according to the desired performance to be imparted to the molded product. For example, synthetic fiber such as vinylon, polypropylene, acrylic, rayon, aramid, etc., inorganic fiber such as glass fiber, potassium titanate, rock wool, etc. In addition to carbon fiber, steel fiber and the like, known fiber materials generally used for inorganic hardening materials such as cement can be used. Further, these fibers may be used in a mesh form, or may be long fibers or short fibers. Incidentally, when using a short fiber, the thickness of the reinforcing fiber is re-aggregated at the time of mixing when it is too thin, fiber balls are easily formed by entanglement, and the strength of the resulting molded article is low and Since the surface irregularities may become severe and a good appearance may not be obtained, if it is too thick or too short, the reinforcing effect tends to be insufficient, so the fiber diameter is from 1 to 50.
It is preferably 0 μm and a fiber length of about 1 to 15 mm.

On the other hand, if the amount of the fiber added is too large, the dispersibility of the fiber, heat resistance, etc. may occur. Therefore, it is preferably 10 parts by weight or less based on 100 parts by weight of the reactive inorganic powder. Inorganic fillers reduce shrinkage during curing and drying,
The fluidity of the slurry can be improved, and examples thereof include silica sand, silica stone powder, slag, talc, mica, and wollastonite, which can be used alone or in combination.

The average particle size of the inorganic filler is 0.01 μm
It is preferably 1 mm or less. That is, if the particle size is too large, the fluidity of the inorganic composition may be deteriorated, or large irregularities may occur on the surface of the obtained inorganic cured body, and if the particle size is too small, the shrinkage during curing and drying is large. There is a risk that the cured product will crack. The amount of the inorganic filler added is 100 parts by weight of the above reactive inorganic powder.
800 parts by weight or less is preferable, 100 parts by weight or more and 500
More preferably, it is not more than parts by weight.

That is, if the amount of the inorganic filler added is too large, the ratio of the reactive inorganic powder decreases, and the curability may be insufficient. The lightweight aggregate is added for the purpose of reducing the weight of the cured product, and may be organic or inorganic, for example, styrene, vinylidene chloride-based,
Synthetic resin foam such as phenol, urethane, ethylene,
Inorganic foams such as glass balloons, shirasu balloons, fly ash balloons, silica balloons and perlite can be used, and these can be used alone or in combination.

If the specific gravity of the lightweight aggregate is less than 0.01, the mechanical strength of the molded product will be reduced, and if it exceeds 1, the effect of weight reduction may not be obtained.
Those of 01 to 1 are preferable. If the addition amount of the lightweight aggregate is less than 0.1 parts by weight with respect to 100 parts by weight of the above reactive inorganic powder, the effect of weight reduction cannot be obtained, and if it exceeds 100 parts by weight, the mechanical strength tends to decrease. Therefore, 0.1-10
About 0 parts by weight is preferable.

The method for producing the curable inorganic composition of the present invention is not particularly limited, but for example, an omni mixer, an Eyrich mixer, a universal mixer, a likai machine or the like which is usually used in producing a cement composition. In addition, a method of supplying and mixing a previously prepared aqueous solution of an alkali metal silicate, the reactive inorganic powder of the present invention, a filler and the like can be mentioned.

The method for obtaining an inorganic molded body from the curable inorganic composition of the present invention is not particularly limited, and a general method used for molding an ordinary inorganic molded body can be used. Method, pressing method, extrusion method and the like. The temperature when curing the curable inorganic composition of the present invention is not particularly limited and may be carried out at room temperature, but if it is too high, the shrinkage during curing will be large and the occurrence of cracks or the like in the obtained inorganic molded body will occur. If it is too low, the curing reaction rate may decrease.
It is preferable to carry out at the following temperature, and it is particularly preferable to carry out at 10 to 150 ° C.

[0024]

[Advantage] According to the above-mentioned constitution, the curability of an appropriate pot life does not occur without the pot life being too short as in the case of using only the highly reactive kaolin powder as the reactive inorganic powder. It becomes an inorganic composition. Moreover, it is possible to obtain a high-strength cured product with good appearance by curing for a short time.

[0025]

EXAMPLES The present invention will be described in detail below with reference to its examples. First, kaolin powder shown below
, And fly ash A to C were prepared. [Kaolin powder] Kaolin (AA kaolin manufactured by Sanyo Clay Co., Ltd. (95% by weight of kaolin mineral, 5% by weight of α-quartz, BET specific surface area of 13 m ² / g)) is an ultra fine mill AT-20 manufactured by Mitsubishi Heavy Industries (Zirconia Ball 10).
mmφ use, ball loading 44kg, kaolin content 2kg,
4.0 kwh / k with 10 g of a mixture of 25% triethanolamine and 75% ethanol as a grinding aid)
It was obtained by applying g mechanical energy.

[Kaolin powder] The kaolin powder was obtained in the same manner as the kaolin powder, except that the added mechanical energy was 1.0 kwh / kg. [Kaolin powder] Kaolin (Aya Kaolin manufactured by Sanyo Clay Co., Ltd. (95% by weight of kaolin mineral, 5% by weight of α-quartz, BET specific surface area of 13 m ² / g)) was ball milled (Makino: ball mill BM150, alumina ball 15).
mmφ used, 200kg ball input, 1 kaolin mixture
5 kg) with 15.0 kwh / kg of mechanical energy applied.

[Kaolin powder] Kaolin that has not been treated at all (AA kaolin manufactured by Sanyo Clay Co., Ltd. (95% by weight of kaolin mineral, 5% by weight of α-quartz, BET specific surface area of 13 m ² / g)) [Fly ash A] fly Ash (manufactured by Kanden Kako Co., Ltd.
An average particle size of 20 μm) [Fly ash B] 98% by weight or more of 10 μm or less powder produced by classifying fly ash A with a classifier (manufactured by Nisshin Engineering Co., Ltd., model: TC-15) Fly ash (average particle size 2 μm) [Fly ash C] Fly ash B at 600 ° C. 3
Time-treated fly ash (average particle size 2 μm) The particle size distribution was determined by a laser diffraction method.

(Examples 1 to 5 and Comparative Examples 1 to 5) Reactive inorganic powders obtained by mixing the above kaolin powders ~ and fly ash A to C at the mixing ratio shown in Table 1 or Table 2,
Silica sand (No. 8 silica sand) as filler and vinylon fiber as reinforcing fiber (RM182 made by Kuraray Co., Ltd. fiber length 6 m
m, fiber diameter 14 μm), potassium silicate as an alkali metal silicate (having a molar ratio of K ₂ O and SiO ₂ of 1.4), and water at the mixing ratios shown in Table 1 or Table 2. The mixture was mixed for 5 minutes with an omni mixer to obtain curable inorganic compositions.

The resulting curable inorganic composition was poured into a mold having a width of 150 mm, a length of 150 mm and a thickness of 10 mm, and was cured in an oven at a predetermined temperature shown in Tables 1 and 2 for a predetermined time. As a result, an inorganic cured body was obtained. The resulting cured inorganic material is cut into a width of 150 mm and a length of 50 m.
m, 10 mm thick test piece was prepared, and the curability, bending strength,
The appearance was evaluated and the results are shown in Tables 1 and 2.

The evaluation method is as follows. [Flexural strength] After demolding, a test piece of the cured product was dried at 50 ° C. for 10 hours and left in an air-dried state for 24 hours.
Bending strength was measured according to the method of A 1408. [Appearance Evaluation] The test piece of the cured product after demolding was visually evaluated for cracks and cracks. Then, the case where there is no abnormality such as cracks or cracks in the appearance is indicated by ◯, and the case where cracks or cracks occur is indicated by x. However,
If it is uncured after being heated for a certain period of time, it is "uncured" as it is.
It was written.

[Evaluation of pot life] The pot life was evaluated as the potable time of the curable inorganic composition in the form of slurry obtained by mixing with an omni mixer.

[0032]

[Table 1]

[0033]

[Table 2] From Tables 1 and 2 above, according to the curable inorganic composition of the present invention, it is of course possible to obtain a high-strength cured product having substantially the same strength as when kaolin powder is used alone. You can see that you can extend the time.

[0034]

The curable inorganic composition according to the present invention comprises:
Since it is configured as described above, it is possible to obtain an inorganic cured product which has a controllable pot life, is excellent in workability, and has high strength and excellent appearance.

Claims (1)

[Claims] 1. Kaolin powders 2 to 8 obtained by acting 20 to 98 parts by weight of fly ash and kaolin with mechanical energy of 0.5 kwh / kg to 30.0 kwh / kg.
100 parts by weight of reactive inorganic powder consisting of 0 parts by weight, 3 to 300 parts by weight of alkali metal silicate, and 10 to 300 parts of water.
And a curable inorganic composition.