JPH08117626A - Production of fly ash granular body and curable inorganic composition using fly ash granular body - Google Patents

Abstract

PURPOSE: To provide a method for efficiently producing a fly ash granular body useful for a curable inorganic composition capable of obtaining a high strength inorganic hardened body and the curable inorganic composition. CONSTITUTION: The fly ash granular body having <=10μm average particle diameter is obtained by applying mechanical energy of 0.05-10kwh/g to a raw material fly ash and after that, the hardened body is obtained by using the curable inorganic composition containing 100 pts.wt. obtained fly ash granular body, 1-300 pts.wt. alkali metal silicate and 10-1000 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 method for producing a fly ash powder and a fly ash powder which can be preferably used as a raw material for producing an inorganic hardened product used in civil engineering, building materials, etc. The present invention relates to a curable inorganic composition using.

[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 alkali metal silicate aqueous solution and metakaolin, corundum or mullite, an alkali-reactive solid component such as fly ash and a filler, an organic bentonite, etc. It is proposed that a curable inorganic composition obtained by mixing the above 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 aqueous solution of an alkali metal silicate, 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 proposed.

[0003]

However, according to the inventors of the present invention, when the fly ash which can be supplied in large quantity and at a low cost among the alkali-reactive solid components shown above is examined, the fly ash is However, it has been found that there is a problem that the reaction rate is very slow and the strength is low in the as-manufactured state.

In order to solve the above problems, the inventors of the present invention classify the fly ash as a raw material, and use only the highly reactive fly ash powder having an average particle size of 10 μm or less as an alkali-reactive solid component. It has been previously proposed to use it (see Japanese Patent Laid-Open No. 6-199517). However, according to this method, although the reactivity is certainly improved and the reaction rate is increased, since only the fly ash powder having an average particle size of 10 μm or less is used for classification, fly ash having a coarse particle size is produced. A large amount remains, and a new processing problem arises. Moreover, there is a problem that the strength of the obtained inorganic cured product is slightly weak.

In view of such circumstances, the present invention provides a method for efficiently producing fly ash powder or granules useful for a curable inorganic composition which can obtain a high-strength inorganic cured product, and the fly ash. It is intended to provide a curable inorganic composition used.

[0006]

In order to achieve such an object, the method for producing fly ash powder granules according to the invention of claim 1 (hereinafter referred to as "invention 1") comprises To obtain fly ash powder with a diameter of 10 μm or less, 0.05 to 10 kwh / k was added to the raw fly ash.
The mechanical energy of g was applied.

The raw material fly ash used in the present invention 1 is defined as JIS A 6201, and has a chemical composition of SiO ₂ ; 45 to 70% by weight, A
l ₂ O ₃ ; 15 to 35% by weight as a main component, and F
Those containing e ₂ O ₃ or CaO as an accessory component are preferably used. In the present invention 1, applying mechanical energy means that the raw material fly ash has attrition force, compression force,
It means adding shearing force, impact force, etc., specifically,
The mechanical energy is applied to the raw fly ash by a pulverizer generally used for pulverization. In addition, after mechanical energy of 0.05 kwh / kg to 10 kwh / kg or less is applied to the raw material fly ash, the obtained fly ash powder or granules are subjected to classification treatment as necessary to adjust to a predetermined particle size. May be.

Examples of the crusher include a jet crusher, a roll mill, various media mills (a crusher in which mechanical energy is applied to fly ash by the movement of a medium such as balls and beads, and more specifically, for example, rolling mills. Container drive type mills such as dynamic mills, vibration mills, planetary mills, medium agitation type mills such as disk type mills, annular type mills, pin type mills, and other container type driven and medium agitation type mills such as ultra fine mills. And the like) are not particularly limited as long as the mechanical energy can be applied to the raw fly ash, but the method of the force acting on the fly ash is a medium mainly composed of grinding, shearing and compression. Mills (for example, medium agitation type mills such as ultra fine mills, container driven type media such as planetary mills and vibration mills that can achieve large maximum acceleration) Bringing Le is particularly preferred) by the action of certain mechanical energy is preferred to enhance the most reactivity of the fly ash powder or granular material.

The mechanical energy may be applied dry or wet. By the way, when mechanical energy is applied by a wet method, the liquid used is not particularly limited, and examples thereof include water, alcohols such as methyl alcohol used for crushing cement clinker or silica sand, limestone, or triethanolamine. ethanol·
Examples of the liquid system include amines, and among these, water is particularly preferable.

When water is used, the fly ash / water weight ratio is preferably 80/20 or less.
0/30 to 30/70 is preferable. In addition, when a predetermined mechanical energy is applied to the raw fly ash by a wet method using water, the fly ash powder of the present invention 1 is slurried with water, but the curable inorganic composition May be added in this slurry state,
You may use after drying once.

The mechanical energy applied to the raw material fly ash is 0.05 kwh / kg or more and 10 kwh / k.
It is limited to g or less. That is, 0.05 kwh / kg
If it is smaller, it is difficult to achieve an average particle size of 10 μm or less, and the reactivity of the resulting fly ash powder is poor. On the other hand, when it is more than 10 kwh / kg, the load on the crushing device is large, the balls and the container as the medium are severely worn, the clay in the treated clay is contaminated, and there are problems in productivity such as cost. The mechanical energy shown above is the electric power supplied to the crushing device when the raw material fly ash is put into operation and expressed per unit weight of the raw material fly ash.

On the other hand, the curable inorganic composition according to the invention of claim 2 (hereinafter referred to as "the present invention 2") is a fly ash powder granule 1 obtained by the production method of the present invention 1.
00 parts by weight, 1 to 300 parts by weight of alkali metal silicate, and 10 to 1000 parts by weight of water. The particle size of the fly ash powder used in the present invention 2 is 10 μm or less in average particle size, preferably 7 μm or less in average particle size, and particularly preferably 5 μm or less in average particle size.

That is, when the average particle size exceeds 10 μm
Even the fly ash powder obtained by the method of the present invention 1
The reactivity is low and the strength of the inorganic cured product is low. Invention 2
Alkali metal silicates used in₂O
・ NSiO ₂(M = Li, K, Na or a mixture thereof)
And those with n = 0.05 to 8 are
Preferably, n = 0.1 to 3 is more preferable, and 0.5 to
2.5 is particularly preferred.

That is, when n exceeds 8, the alkali metal silicate aqueous solution is apt to gel, and the viscosity rapidly increases due to gelation, which may make it difficult to mix with the powder. The alkali metal silicic acid is preferably added as an aqueous solution. The concentration of the aqueous solution is not particularly limited, but if the concentration is too low, the reactivity with the fly ash powder is reduced, and conversely, if the concentration is too high, solid content tends to occur, so it is necessary to be 1% by weight or more, 1 to 70% by weight is 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, but the alkali metal hydroxide aqueous solution may contain SiO ₂ components such as silica sand and silica stone powder. What melt | dissolved so that n might become predetermined amount may be used. The addition amount of the alkali metal silicate needs to be 1 to 300 parts by weight with respect to 100 parts by weight of the fly ash powder and granules, but is 1 to 250 parts by weight.
It is preferable that the amount is 10 parts by weight, and more preferably 10 to 150 parts by weight. That is, if the amount of the alkali metal silicate added is less than 1 part by weight, the reactivity with the inorganic powder is low, and conversely, if it is more than 300 parts by weight, the mechanical strength of the obtained inorganic molded body decreases.

The amount of water added is such that fly ash powder 10
It is necessary to be 10 to 1000 parts by weight with respect to 0 parts by weight, but preferably 15 to 750 parts by weight,
It is more preferable that the amount is 400 parts by weight. That is,
If the amount of water added is less than 10 parts by weight, it becomes impossible to mix with the inorganic powder. On the contrary, if it exceeds 1000 parts by weight, the mechanical strength of the obtained inorganic molded body decreases.

Furthermore, reinforcing fibers, inorganic fillers, lightweight aggregates, other additives, foaming agents, foaming aids and the like may be added to the curable inorganic composition of the present invention 2 as required. it can. As the reinforcing fiber, any material can be used according to the performance desired to be imparted to the molded product, and examples thereof include synthetic fibers such as vinylon, polypropylene, acrylic, rayon and aramid, glass fibers, inorganic fibers such as potassium titanate and rock wool, carbon fibers. In addition to steel fibers, known fiber materials that are 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. Inorganic fillers reduce shrinkage during curing and drying,
It is possible to improve the fluidity of the slurry. For example, silica sand, silica stone powder, crystalline alumina, alumina, talc, mica, diatomaceous earth, mica, rock powder (shirasu, anti-firestone, etc.),
Examples thereof include basalt, feldspar, wollastonite, clay, bauxite, sepiolite, and various minerals, and these 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 addition amount of the inorganic filler is preferably 900 parts by weight or less, more preferably 100 parts by weight or more and 700 parts by weight or less, and particularly preferably 50 parts by weight or more and 500 parts by weight or less. That is, if the amount of the inorganic filler added is too large, the mechanical strength of the inorganic cured product may be reduced.

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, phenol,
Examples thereof include synthetic resin foams such as urethane and ethylene, and inorganic foams such as glass balloons, shirasu balloons, fly ash balloons, silica balloons and pearlite, and these may 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.
01 to 1 is preferable, and 0.03 to 0.7 is particularly 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 fly ash powder, the effect of weight reduction cannot be obtained, and if it exceeds 100 parts by weight, the mechanical strength tends to decrease. Therefore, it is preferably about 0.1 to 100 parts by weight.

Other additives include alumina cement, γ-alumina, sprayed alumina, alkali metal aluminate, for improving heat resistance and reaction rate.
Examples thereof include one or more aluminum-based additives selected from the group consisting of aluminum hydroxide, calcium oxide for promoting the curing reaction, and various cements. The alumina cement is Al ₂ O ₃ of 30% or more and Ca
O is 50% or less, and refers to an inorganic powder containing lime aluminate as a main component, and refers to all varieties listed in JIS R2511.

The term "γ-alumina" refers to an alumina powder having a crystallinity worse than that of α-alumina obtained by heating and dehydrating bauxite, hydrated aluminum oxide and the like at several hundred degrees. The sprayed alumina is A obtained by the high temperature spraying method.
A powder containing 70% or more of 1 ₂ O ₃ . Alkali metal aluminate means mM ₂ O · Al ₂ O ₃ (M = K,
At least one metal selected from Na and Li, m = 0.1
It refers to the salt represented by 5).

The amount of the aluminum-based additive added is 3 with respect to 100 parts by weight of fly ash powder.
The amount is preferably 00 parts by weight or less, more preferably 1 part by weight or more and 200 parts by weight or less, particularly preferably 5 parts by weight or more and 100 parts by weight or less. That is, if the amount of the aluminum-based additive added is too large, the mechanical strength of the obtained inorganic cured product may be reduced.

On the other hand, the addition amount of calcium oxide or various cements is preferably 300 parts by weight or less, and particularly preferably 0.5 parts by weight or more and 100 parts by weight or less, relative to 100 parts by weight of fly ash powder. That is, if the amount of calcium oxide or various types of cement added is too large, the composition may be rapidly hardened, which may make moldability difficult. The foaming agent is not particularly limited as long as it reacts with the alkali metal silicate aqueous solution to generate a gas, and examples thereof include hydrogen peroxide, sodium peroxide, potassium peroxide, sodium perborate and the like. Thing, Mg, Ca, C
r, Mn, Fe, Co, Ni, Cu, Zn, Al, G
Examples include metal powders such as a, Sn, Si, and ferrosilicon. These may be used alone or in combination of two or more.

The amount of the foaming agent added is preferably about 0.01 to 10 parts by weight per 100 parts by weight of fly ash powder. If the amount of the foaming agent added is too small, a foam having a high expansion ratio cannot be obtained, and if it is too large, the foam may be broken. In addition,
When hydrogen peroxide is used as the foaming agent, it is preferably added as an aqueous solution, but when the concentration of the hydrogen peroxide is too thin, the viscosity of the composition decreases and a stable foam cannot be obtained. If it is too thick, foaming may become too fast and a stable foam may not be obtained.
It is preferably about 5% by weight.

On the other hand, when the metal powder is used as the foaming agent, the reactivity becomes too high when the average particle size of the metal powder becomes small, and a stable foam cannot be obtained. It is preferable to use a metal powder having an average particle size of about 1 to 200 μm, because a foam having a high ratio may not be obtained. The foaming aid is not particularly limited as long as it uniformly causes foaming, for example, zinc stearate, calcium stearate, fatty acid metal salts such as zinc palmitate, silica gel, zeolite, activated carbon, porous powder such as alumina powder. The body etc. are mentioned.

These may be used alone or in combination of two or more kinds. If the amount of the foaming aid added increases, the viscosity of the composition may increase, and a stable foam may not be obtained, so 5 parts by weight or less is preferable. The method for producing the curable inorganic composition of the present invention 2 is not particularly limited, but, for example, in the case of producing a cement composition, it is prepared in advance in an omni mixer, an Eirich mixer, an all-purpose mixer, a likai machine or the like which is usually used. The method of supplying and mixing the alkali metal silicate aqueous solution, the fly ash powder and granular material of the present invention 1, the filler, and the like.

The method for obtaining an inorganic molded body from the curable inorganic composition of the present invention 2 is not particularly limited, and a general method used for a cement molded body or the like is used, for example, an injection method or a pressing method. Extrusion method and the like. The temperature at which the curable inorganic composition of the present invention 2 is cured is
It is not particularly limited and may be carried out at room temperature, but if it is too high, shrinkage during curing may be large and cracks may occur in the resulting inorganic molded body, and if it is too low, the curing reaction rate may decrease. Therefore, it is preferably performed at 1 ° C. or higher and 300 ° C. or lower, particularly preferably 10 ° C. or higher and 150 ° C. or lower.

[0030]

According to the manufacturing method of the present invention 1, the raw fly ash has an average particle size of 10 μm due to mechanical energy.
The following fly ash powder and granules are formed, and problems such as discarding fly ash having a coarse particle size are solved. Moreover, the obtained fly ash powder and granules become highly reactive when used as an alkali-reactive solid component.

On the other hand, according to the curable composition of the present invention 2,
Since the highly reactive fly ash powder obtained by the production method of the present invention 1 is contained in the composition as an alkali-reactive solid component, an inorganic cured product having excellent moldability and high strength can be obtained. .

[0032]

EXAMPLES The present invention will be described in detail below with reference to its examples. (Example 1) Raw material fly ash {made by Kandenko Kako Co., Ltd.
Average particle size 19.4 μm} made by Mitsubishi Heavy Industries, Ltd. Ultra Fine Mill AT-20 (Cr steel ball 10 mmφ used, ball filling rate 65%, fly ash mixing amount 3.9 kg)
Then, dry ash powder was produced by applying mechanical energy of 0.12 kwh / kg.

(Example 2) Fly ash powder was prepared in the same manner as in Example 1 except that mechanical energy of 0.63 kwh / kg was applied. (Example 3) A fly ash powder was produced in the same manner as in Example 1 except that mechanical energy of 1.20 kwh / kg was applied.

(Example 4) Raw material fly ash {Kanden Kako Co., Ltd. average particle size 19.4 μm} was converted to Mitsubishi Heavy Industries Co., Ltd. ultra fine mill AT-20 (using alumina balls 10 mmφ, ball filling rate 70%, Fly ash / water weight ratio = 60/40, fly ash 4.34
After applying mechanical energy of 0.23 kwh / kg for 12 hours, the obtained slurry was dried for 12 hours with a hot air dryer at 100 degrees to produce fly ash powder.

(Example 5) Raw material fly ash {Kanden Kako Co., Ltd. average particle size 19.4 μm} was converted to Kurimoto Iron Works Co., Ltd. planetary mill {Hisie BX254, zirconia balls 3 mmφ used, ball filling rate 60% by volume}. 0.3
Fly ash powder was produced by applying mechanical energy of 0 kwh / kg.

(Example 6) A raw material fly ash {average particle size 19.4 μm manufactured by KANDEN KAKO CO., LTD.> Was used as a ball mill manufactured by Makino Co., Ltd.
0.60kWh / k when used, ball filling rate 60% by volume)
Fly ash powder was produced by applying mechanical energy of g.

(Comparative Example 1) Raw material fly ash {average particle size 19.4 μm manufactured by KANDEN KAKO CO., LTD.} Was classified using a classifier (Nisshin Engineering Co., Ltd., trade name TC-15) and fly ash was classified. Powder I was prepared. (Comparative Example 2) Raw material fly ash {made by Kandenko Kako Co., Ltd.
The average particle diameter of 19.4 μm} is used by Mitsubishi Heavy Industries Ultra Fine Mill AT-20 (Cr steel ball 10 mmφ used, ball filling rate 65%, fly ash content 3.9 kg) to produce 0.02 kwh / kg mechanical energy by dry method. It was made to act, and the fly ash powder granular material II was produced.

The average particle size of each of the fly ash powders I, II and II obtained in Examples 1 to 6 and Comparative Examples 1 and 2 was measured, and the results are shown in Table 1. In addition, the average particle diameter was measured using a particle size analyzer (laser diffraction type particle size distribution meter, manufactured by Seishin Enterprise Co., Ltd .: PRO-7000S).

[0039]

[Table 1]

(Examples 7 to 13 and Comparative Examples 3 to 7) Any one of the fly ash powders ~, I and II obtained in Examples 1 to 6 and Comparative Examples 1 to 2 was used. The compositions having the formulations shown in Table 3 were mixed with an omni mixer for 5 minutes to obtain a curable inorganic composition. And each curable inorganic composition is 150 mm in width, 150 mm in length, and 1 in thickness.
It was poured into a 0 mm mold and cured in an oven at the curing temperatures shown in Tables 2 and 12 for 12 hours to obtain an inorganic cured product.

The resulting inorganic cured body is cut to have a width of 15
A test piece having a length of 0 mm, a length of 50 mm and a thickness of 10 mm was prepared, and the bending strength and the appearance were evaluated by the following evaluation methods, and the results are also shown in Tables 2 and 3. -Evaluation method (1) Bending strength After hardening the above-mentioned test piece for 12 hours shown in a table, it is 10 at 50 degreeC.
After drying for 24 hours, leave it in the air-dried state for 24 hours.
Bending strength was measured according to the method of A 1408. (2) Appearance evaluation The state (cracks, cracks, etc.) of the inorganic molded body was visually evaluated. ◯: No abnormalities such as cracks and cracks in appearance X: Cracks and cracks However, if it is uncured even after heating for a predetermined time, it is described as “uncured” as it is. The silica sand and vinylon fiber used were RM182 manufactured by Kuraray Co., Ltd., having a length of 6 mm and a diameter of 14 μm.

[0042]

[Table 2]

[0043]

[Table 3] From Tables 2 and 3, it can be seen that a cured product excellent in appearance and bending strength can be obtained by using the fly ash powder and granules of the present invention 1 together with the composition of the present invention 2.

[0044]

INDUSTRIAL APPLICABILITY As described above, according to the method for producing a fly ash powder of the present invention 1, the fly ash, which has conventionally been poor in reactivity, can be made excellent in reactivity. In addition, since coarse fly ash powder and granules are eliminated and all can be used, it is advantageous for mass production.

On the other hand, the curable inorganic composition of the present invention 2 comprises
Since the fly ash powder obtained by the production method of the present invention 1 having excellent reactivity is used as an alkali-reactive solid component, the inorganic hardened product has good moldability and high strength,
Suitable for civil engineering and building materials.

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Claims (2)

[Claims] 1. To obtain a fly ash powder having an average particle size of 10 μm or less, the raw fly ash has a content of 0.05 to
A method for producing fly ash powder, which comprises applying a mechanical energy of 10 kwh / kg. 2. A curable inorganic material containing 100 parts by weight of fly ash powder and granules obtained by the production method according to claim 1, 1 to 300 parts by weight of alkali metal silicate, and 10 to 1000 parts by weight of water. Composition.