JPH10101323A - Inorganic powder, inorganic curable composition and inorganic cured body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inorganic powder having high reactivity with an alkali, especially an alkali metal silicate aqueous solution, and an inorganic hardened body having excellent curability and excellent strength and water resistance. And a cured inorganic material thereof. SOLUTION: The Al ₂ O ₃ -SiO ₂ -based inorganic powder containing Al ₂ O ₃ component 10 wt% or more, the A
l ₂ O ₃ suspension prepared by dispersing -SiO ₂ based inorganic powder in water, Al ₂ O ₃ -SiO ₂ is pH7.5~11
Based inorganic powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Inorganic cured products are useful as nonflammable, smokeless building materials. As such,
For example, an inorganic cured product that is cured by heat in the presence of an alkali has been proposed. JP-A-4-59648 discloses an alkali metal silicate aqueous solution and ash of a dust collecting device generated during production of metakaolin, corundum or mullite.
There is disclosed a technique for producing an inorganic cured material useful as a building material by mixing an alkali-reactive inorganic solid component such as fly ash and mixing an admixture such as a filler and organic bentonite. Also, Japanese Patent Application Laid-Open No.
No. 138 discloses an inorganic cured product obtained by kneading an alkali metal silicate aqueous solution, the above-described alkali-reactive inorganic solid component, and a filler, injecting the resulting mixture into a mold, and curing by heating.

However, among such alkali-reactive inorganic solid components, kaolin and fly ash that can be supplied stably and inexpensively have been studied.
Due to high crystallinity, reactivity with alkali is insufficient,
A good inorganic cured product cannot be obtained. Fly ash has problems in that the reactivity varies depending on the power plant that produces it, and that the reaction speed is extremely slow.

[0004]

DISCLOSURE OF THE INVENTION In view of the above, the present invention provides an inorganic powder having high reactivity with an alkali, particularly an alkali metal silicate aqueous solution, excellent curability, and high strength and water resistance. An object of the present invention is to provide an inorganic curable composition from which an excellent inorganic cured product can be obtained, and an inorganic cured product thereof.

[0005]

Means for Solving the Problems The present invention relates to a Al ₂ O ₃ -SiO ₂ -based inorganic powder containing Al ₂ O ₃ component 10 wt% or more, the Al ₂ O ₃ -SiO ₂ -based mineral powder and the dispersed in water suspension, is Al ₂ O ₃ -SiO ₂ -based inorganic powder is PH7.5～11. Hereinafter, the present invention will be described in detail.

The Al ₂ O ₃ —SiO ₂ based inorganic powder of the present invention contains an Al ₂ O ₃ component in an amount of 10% by weight or more. 10
If the content is less than 10% by weight, the amount of Al contributing to the reaction with the aqueous solution of the alkali metal silicate is small, so that the curing does not proceed sufficiently. Preferably, Al ₂ O
₃ component is 20 to 90 wt%, and, SiO ₂ component is 10 to 80 wt%.

The Al ₂ O ₃ —SiO ₂ inorganic powder of the present invention has a pH of 7.5 to 11 in a suspension dispersed in water. If it is less than 7.5, the reaction rate with the aqueous alkali metal silicate solution is low, and if it exceeds 11, the resulting cured product has low density and thus deteriorates in quality such as strength, and is limited to the above range. . The above suspension is 20 g of the Al ₂ O ₃ —SiO ₂ inorganic powder of the present invention per 100 g of distilled water.
Is added and mixed for about 30 minutes.

The Al ₂ O ₃ —SiO ₂ based inorganic powder of the present invention applies mechanical energy of 0.1 to 30 kWh / kg to an inorganic powder containing an Al ₂ O ₃ component of 10% by weight or more. Can be manufactured.

The inorganic powder containing 10% by weight or more of the above-mentioned Al ₂ O ₃ component (hereinafter referred to as “raw material powder”) is not particularly limited, and examples thereof include kaolin;
Diaspore (α-Al ₂ O ₃ .H ₂ O), boehmite (γ-Al ₂ O ₃ .H ₂ O), hydrargillite (γ
_{-Al 2 O 3 · 3H 2 O} ) hydrated such as alumina; bauxite; alum shale; aluminum hydroxide; sillimanite, kyanite, sillimanite group mineral, such as the under Ryu site (Al ₂ SiO _5); mullite (3Al ₂ O _3.
2SiO ₂ ); fly ash; metakaolin; glass powder; dust generated during the production of alumina-based abrasives; and Al-containing powders such as calcined bauxite. These may be used alone or as a mixed powder of two or more types.

The raw material powder may be used as a mixed powder with a powder containing high SiO ₂ such as silica fume, diatomaceous earth, silica stone, aerosil, and clay. In this case, in the average composition of the mixed powder, the Al ₂ O ₃ component is 10% by weight.
Must be exceeded.

Although the average particle size of the raw material powder is not particularly limited, it is preferably 0.0
01 nm to 1 mm is preferred. More preferably, 0.0
05 nm to 100 μm.

The mechanical energy is not particularly limited, and includes, for example, energy due to compressive force, shear force, impact force and the like. The method for applying the mechanical energy is not particularly limited, and the method can be performed using a crusher generally used for the purpose of crushing.
Examples of such a pulverizer include ball media mills such as ball mills, vibration mills, planetary mills, and media stirring mills that combine impact, friction, compression, and shear; roller mills; mortars, and the like. It is also possible to use a jet crusher whose main purpose is impact and grinding. Among them, a ball medium mill is preferable because mechanical energy can be effectively applied to the raw material powder mechanically.

At the time of the above-mentioned pulverization, a pulverization auxiliary usually used at the time of pulverization of cement clinker, silica sand, limestone and the like can be used. Examples of the grinding aid include alcohols such as methyl alcohol; liquids such as ethanolamines such as triethanolamine; solids such as sodium stearate and calcium stearate; and gases such as acetone vapor. And the like.

[0014] The mechanical energy represents the electric power supplied to the pulverizing device per unit weight of the processing raw material, and is 0.1 0.1
~ 30 kwh / kg is preferred. If it is less than 0.1 kwh / kg, the reactivity of the obtained Al ₂ O ₃ —SiO ₂ -based inorganic powder will not be sufficiently improved, and if it exceeds 30 kwh / kg, an excessive load on the pulverizing apparatus and a medium Various problems such as excessive wear of the balls and the container, mixing of impurities into the processed powder, and productivity such as cost arise. The average particle diameter of the Al ₂ O ₃ —SiO ₂ based inorganic powder obtained by the above mechanical energy is preferably 0.1 to 300 μm. More preferably, it is 0.1 to 50 μm.

The reason why the Al ₂ O ₃ —SiO ₂ -based inorganic powder of the present invention has high reactivity with an aqueous solution of an alkali metal silicate is unknown, but the powder composition and the basicity of the powder are unclear. Those in the above-mentioned range are presumed to be due to the high interaction with the alkali ion as a cation, and the dissolution of the reaction component is likely to proceed.

The present invention 2 relates to the Al ₂ O ₃ —SiO of the present invention.
It is an inorganic curable composition comprising a ₂ system inorganic powder, an alkali metal silicate, and water. The alkali metal silicate is represented by a general formula: M ₂ O · nSiO ₂ (where M represents Li, K or Na; n represents 0 or a positive integer). In the above formula,
n is preferably 8 or less. If it exceeds 8, when it is mixed with water to form an aqueous solution of an alkali metal silicate, gelation is likely to occur, and the viscosity sharply increases, and the Al ₂ O ₃ —S
Mixing with the iO ₂ -based inorganic powder becomes difficult. The alkali metal silicates may be used alone or in combination of two or more.

The amount of the alkali metal silicate is preferably ₃ to 300 parts by weight based on 100 parts by weight of the Al ₂ O ₃ —SiO ₂ inorganic powder. If the amount is less than 3 parts by weight or exceeds 300 parts by weight, the curability of the obtained inorganic curable composition will be insufficient. More preferably, 10
200 parts by weight.

The mixing amount of the water is the same as that of the Al ₂ O ₃ —Si
The amount is preferably from 10 to 300 parts by weight based on 100 parts by weight of the O ₂ -based inorganic powder. If it is less than 10 parts by weight, molding of the obtained inorganic curable composition becomes difficult, and if it exceeds 300 parts by weight, the strength of the inorganic cured product obtained by curing the obtained inorganic curable composition decreases. . More preferably, it is 15 to 200 parts by weight.

In preparing the inorganic curable composition of the present invention 2, from the viewpoint of the dispersibility of the alkali metal silicate, the alkali metal silicate is previously mixed with water and added as an aqueous alkali metal silicate solution. Is preferred. In this case, the concentration of the aqueous alkali metal silicate solution is preferably from 1 to 70% by weight. When the amount is less than 1% by weight, the obtained inorganic curable composition may not be cured. When the amount is more than 70% by weight, the viscosity of the obtained inorganic curable composition becomes high and molding becomes difficult. More preferably, it is 30 to 60% by weight.

In the inorganic curable composition of the present invention 2, reinforcing fibers, inorganic fillers, lightweight aggregates and the like can be added as required. The reinforcing fiber is appropriately selected according to the performance to be provided to the formed inorganic cured product. The reinforcing fiber is not particularly limited as long as it is generally used for an inorganic hardened material such as cement. For example, synthetic fibers such as vinylon, polypropylene, acrylic, rayon, and aramid; glass fibers; potassium titanate And inorganic fibers such as rock wool; carbon fibers; steel fibers and the like.

The reinforcing fiber may be either a long fiber or a short fiber, and may be used in a mesh form. When using short fibers, the fiber diameter is 1 to 5
The fiber length is preferably 1 to 15 mm. If it is too thin, it is likely to re-agglomerate during mixing and fiber balls are likely to be formed by entanglement, so that the strength of the obtained inorganic cured product becomes insufficient, and the surface becomes too rough to obtain a good appearance. . On the other hand, if it is too thick or too short, the reinforcing effect becomes insufficient.

The amount of the reinforcing fibers to be added depends on the amount of the Al ₂ O ₃
Preferably 10 parts by weight or less relative -SiO ₂ based inorganic powder 100 parts by weight. If the amount exceeds 10 parts by weight, problems occur in the dispersibility of the reinforcing fibers, the heat resistance of the obtained inorganic cured product, and the like.

The inorganic filler is added to reduce the shrinkage of the inorganic cured product during curing and drying and to improve the fluidity of the slurry. The inorganic filler is not particularly limited, and examples thereof include silica sand, silica stone powder, fly ash, slag, silica fume, mica, talc, wollastonite, calcium carbonate, clay and the like.

The above-mentioned inorganic filler has an average particle size of 0.01
μm to 1 mm is preferred. If less than 0.01 μm,
The effect of reducing shrinkage during curing and drying is insufficient. If it exceeds 1 mm, the fluidity deteriorates, and the unevenness of the surface of the obtained inorganic cured product increases. The amount of the inorganic filler to be added depends on the amount of the Al ₂ O ₃ —SiO ₂ inorganic powder 1
It is preferably 800 parts by weight or less based on 00 parts by weight. 80
If it exceeds 0 parts by weight, the curability becomes insufficient because the proportion of the Al ₂ O ₃ —SiO ₂ -based inorganic powder becomes small. More preferably, it is 100 to 500 parts by weight.

The above-mentioned lightweight aggregate is added to reduce the weight of the obtained inorganic cured product. The lightweight aggregate is not particularly limited, and may be organic or inorganic. For example, various synthetic resins such as styrene, vinylidene chloride, phenol, urethane, and ethylene may be used. Foams; inorganic foams such as glass balloons, shirasu balloons, fly ash balloons, silica balloons, and pearlite. These may be used alone or in combination of two or more.

The specific gravity of the foam is preferably from 0.01 to 1. If it is less than 0.01, the strength of the obtained cured inorganic material is reduced. If it exceeds 1, the effect of weight reduction cannot be obtained. The amount of the lightweight aggregate added is the same as that of the Al ₂ O ₃ —SiO
_{The amount} is preferably 0.1 to 100 parts by weight based on 100 parts by weight of the _second inorganic powder. If the amount is less than 0.1 part by weight, the effect of reducing the weight cannot be obtained, and if it exceeds 100 parts by weight, the strength of the obtained inorganic cured product is reduced.

The method for producing the inorganic curable composition of the present invention 2 is not particularly limited, and examples thereof include an omni mixer, an Eirich mixer, a universal mixer, a raikai machine and the like which are usually used when producing a cement composition. Using an aqueous alkali metal silicate solution prepared in advance, the Al _{2 of} the present invention
A method in which an O ₃ —SiO ₂ -based inorganic powder, a filler, and the like are blended and mixed is exemplified.

[0028] The present invention 3 is an inorganic cured product obtained by curing the inorganic curable composition of the present invention 2. The inorganic cured product of the third aspect of the present invention can be obtained by curing the inorganic curable composition of the second aspect of the present invention by a general method. For example, an injection method, a press method, an extrusion method, or the like can be used.

The curing temperature for producing the inorganic molded article of the present invention 3 is preferably 1 to 300 ° C. If it is less than 1 ° C,
The curing reaction rate may decrease, and if it exceeds 300 ° C., the shrinkage during curing increases, and cracks and the like may occur in the obtained inorganic cured product. More preferably,
10-150 ° C.

[0030]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Examples 1 to 3 and Comparative Examples 1 to 4 Ultra Fine Mill AT-20 (manufactured by Mitsubishi Heavy Industries, Ltd.
0 kgφ zirconia balls 44 kg), 2 kg of starting materials shown in Table 1, and 10 g of a mixture of 25% triethanolamine and 75% ethanol as grinding aids
, And an inorganic powder was prepared under the conditions shown in Table 1.

As the starting material, clay (average particle size: 7 μm)
m, chemical composition Al ₂ O ₃ : 16%, SiO ₂ : 76
%), Aluminum hydroxide (average particle diameter 52 μm, chemical composition Al ₂ O ₃ : 67%, SiO ₂ : 0%), aerosil (average particle diameter 0.012 nm, chemical composition Al ₂ O ₃ : 0)
%, SiO ₂ : 100%) and kaolin (average particle size 2.
4 μm, chemical composition Al ₂ O ₃ : 42%, SiO ₂ : 37
%). The average particle size of the starting materials was measured using laser diffraction, and the chemical composition was measured using fluorescent X-rays.

[0033]

[Table 1]

The properties of the obtained inorganic powder were evaluated by the following methods. The results are shown in Table 2. Evaluation methods (1) content of the Al ₂ O ₃ component in the Al ₂ O ₃ component resulting inorganic powder (wt%) was measured using the fluorescent X-ray.

(2) pH value 100 g of distilled water (pH 6.8) and the obtained inorganic powder 2
The electrode of the pH meter was put into the suspension prepared by mixing 0 g with the mixture for 30 minutes, and the pH reading when the indicator was stopped was measured.

(3) Reactivity with alkali metal silicate aqueous solution 100 g of inorganic powder and alkali metal silicate aqueous solution (Si
O ₂ : 21%, Na ₂ O: 15%, water 64%) 200 g
After mixing for 2 minutes, the time during which the slurry solidified under a 13 ° C. environment was measured. When solidification was observed, the time was described, and when solidification was not observed after 12 hours or more, it was evaluated as x.

[0037]

[Table 2]

As shown in Table 2, the inorganic powders prepared in Examples 1 to 3 were classified as types A to C, and the inorganic powders prepared in Comparative Examples 1 and 2 were classified as types a and b, respectively. It was used in the following Examples and Comparative Examples.

Examples 4 to 8 and Comparative Examples 5 and 6 The compositions having the compositions shown in Tables 3 and 4 were mixed for 5 minutes with an omni mixer to obtain an inorganic curable composition. The obtained inorganic curable composition was poured into a mold having a width of 50 mm, a length of 150 mm, and a thickness of 10 mm, cured in a mold at room temperature for 3 hours, and then demolded to obtain an inorganic cured product.

The obtained cured inorganic material was evaluated by the following method. The results are shown in Tables 3 and 4. In Tables 3 and 4, silica powder was manufactured by Sumitomo Cement Co., Ltd., and Blaine specific surface area was 9000 cm ² / g, wollastonite was Chemolit A-60 (Wolchem), and vinylon fiber was R
M182 (fiber length 6 mm, fiber diameter 14 μm, manufactured by Kuraray Co., Ltd.).

Evaluation method (1) Flexural strength The obtained cured inorganic material was left in an air-dried state for 24 hours.
The bending strength was measured according to the method of JIS A1408. (2) Hot water test (promoted water resistance test) The obtained cured inorganic material was immersed in hot water of 98 ° C for 2 hours, dried for 24 hours, measured for bending strength by the above method, and maintained strength. Was measured.

[0042]

[Table 3]

[0043]

[Table 4]

[0044]

As described above, the Al ₂ O ₃ —SiO ₂ inorganic powder of the present invention has very high reactivity with an aqueous alkali metal silicate solution. Further, the Al ₂ O of the present invention
_The inorganic curable composition using the _3- SiO ₂ -based inorganic powder can obtain a cured inorganic substance having high curing reactivity and excellent strength and water resistance.

Claims (3)

[Claims] 1. Al_TwoO_ThreeContains at least 10% by weight of components
Al_TwoO_Three-SiO _TwoThe inorganic powder according to the above A,
l_TwoO_Three-SiO_TwoSuspension of inorganic powder in water
Wherein the turbid liquid has a pH of 7.5 to 11.
_TwoO_Three-SiO_TwoBased inorganic powder. 2. An inorganic curable composition comprising the Al ₂ O ₃ —SiO ₂ -based inorganic powder according to claim 1, an alkali metal silicate, and water. 3. An inorganic cured product obtained by curing the inorganic curable composition according to claim 2.