JP2863106B2 - Manufacturing method of lightweight multilayer solidified material - Google Patents

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 lightweight multi-layer solidified product having different pore distributions, and more particularly to a method for producing a building material such as a building panel and a sound absorbing material.

[0002]

2. Description of the Related Art ALC (autoclaved light weight conc)
Rete) is lightweight autoclaved aerated concrete, and is widely used in houses and the like as a lightweight and durable architectural panel having excellent fire resistance, heat insulation and soundproofing properties. However, since the porosity is large in the strength, it is necessary to insert a reinforcing material such as a reinforcing bar in a place where the strength is required such as a floor material.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a lightweight multi-layer solidified material having a different pore distribution which is lightweight and has high strength even without a reinforcing material. .

[0004]

SUMMARY OF THE INVENTION A first method of the present invention for producing a lightweight multi-layered solid product has been made to solve the above-mentioned problems.
Discloses a method of producing a plurality of mixtures of a raw material, a foaming agent, and water consisting of at most 90% by weight of coal ash and 10% by weight or more of a calcium compound, forming these mixtures into a laminate, It is characterized by performing hydrothermal treatment at a high temperature of not less than ℃ and high pressure. In the second invention, a plurality of types of mixtures of a raw material, a foaming agent, and water composed of at most 90% by weight of coal ash and 10% by weight or more of a calcium compound are produced, and these mixtures are formed into a laminate. Then, hydrothermal treatment is performed at a high temperature of 120 ° C. or higher and a high pressure. Further, the third invention produces a plurality of mixtures of water and a raw material comprising at most 90% by weight of coal ash and 10% by weight or more of a calcium compound,
A step of mixing predetermined amounts of air bubbles prepared in advance with a foaming agent into the mixture, forming the mixture into a laminate, and then performing a hydrothermal treatment at a high temperature of 120 ° C. or higher and a high pressure. A method for producing a lightweight multilayer solidified product.

[0005] The calcium compound is preferably at least one or more of calcium oxide, calcium hydroxide, calcium carbonate and calcium silicate.

Prior to the hydrothermal treatment, 30 to 1
Curing at 00 ° C. is also suitable.

[0007]

[Action]

When the mixing ratio of the coal ash exceeds 90% by weight, it is difficult to solidify, and the solid form as a light-weight solidified product cannot be maintained. Therefore, the mixing ratio of coal ash is 90% by weight.
Hereinafter, it is preferably 30 to 80% by weight.

Examples of the calcium compound which can be employed in the present invention include calcium oxide, calcium hydroxide, calcium silicate, calcium carbonate and the like. These compounds may be used alone or in combination of two or more. Can be used together. Here, calcium silicate is alite (3CaO.SiO ₂ ),
Belite (2CaO.SiO ₂ ) and the like, and various portland cements including these, such as ordinary portland cement, can also be used. Among these compounds, calcium silicate, calcium oxide, and calcium hydroxide are particularly preferable from the viewpoint of action and effect. In addition, calcium sulfate such as gypsum is not suitable to be added in large amounts because products other than tobermorite are formed.

[0010] As the foaming agent, aluminum powder, calcium powder and lime chloride powder are used, but aluminum powder is preferred. From the viewpoint of improving strength, the amount of the foaming agent is preferably 0.01 to 1% by weight based on the solid content,
The particle size is preferably from 1 to 300 μm.

In order to prepare a slurry which is a mixture from a calcium compound and coal ash, a predetermined amount of coal ash, a predetermined amount of calcium compound and a predetermined amount of a foaming agent are mixed, and then water, preferably hot water of 40 ° C. or more, is mixed. 20 to 100 based on solid content
It is preferable to add by weight in terms of improving strength and foaming for uniformly dispersing bubbles. At this time, an admixture such as a water reducing agent, a water retention agent, a waterproofing agent, a fluidizing agent, a shrinkage reducing agent, a foam stabilizer, a surfactant, and the like may be added, and the strength of the lightweight solidified product is improved and the specific gravity is adjusted. In order to reduce the cost, silica sand, igneous rock, blast furnace slag, perlite, ALC waste, glass fiber, fiber, pulp and the like can be added. Examples of the admixture include alkyl allyl sulfonic acid, a highly condensed naphthalene sulfonic acid formalin, a cocondensate of naphthalene sulfonic acid and lignin sulfonic acid, an alkyl allyl sulfonate polymer, an alkyl allyl sulfonate, a formalin condensate of diethyl naphthalene, and olefin / maleic anhydride. Examples include acid co-condensates, polycarboxylates, modified methylol melamine condensates, polyvinyl alcohol, methyl cellulose, and the like.

In addition, the slurry containing coal ash, calcium compound and foaming agent reacts with a SiO ₂ component such as coal ash, a calcium component such as a calcium compound, and water to react with a CSH gel (calcium silicate hydrate). (Petgel) and calcium hydroxide. The calcium hydroxide and the calcium compound react with the foaming agent (eg, metal aluminum powder) and water to generate hydrogen and the like, thereby generating air bubbles in the slurry. Therefore, the porosity in the slurry can be controlled to a desired value by changing the type and amount of the blowing agent. The type and amount of coal ash, calcium compound, and water can be changed in consideration of strength or pouring properties.

Using the slurry thus adjusted, it is poured into a predetermined mold by casting or the like. At this time, the porosity distribution is mainly divided into the following four types. A type in which the porosity between the two surfaces changes from low to high, a type in which the porosity between the two surfaces changes from low to high to low, and a type in which the porosity between the two surfaces changes from high to low to high Type, mixed type above. In any case, it is preferable from the viewpoint of strength that the time for pouring each slurry be within 2 hours. Also, considering the strength and water absorption, the outer surface (bottom or top surface of the mold)
It is desirable not to add a foaming agent to the slurry into which the part is poured. Since the porosity distribution preferably changes continuously in terms of strength, it is better to adjust the amount of the foaming agent in each slurry so as to change continuously. When the mixing ratio of the coal ash and the calcium compound is also changed, it is preferable that the mixing ratio be changed continuously in terms of strength. Since the above is slightly inferior in dimensional stability and strength, use outdoors is not preferable.
In addition to pouring in parallel to the bottom surface of the mold, it is also possible to pour in a layered manner in a direction perpendicular to the bottom surface by partitioning the mold.

[0014] When the slurry is poured into the mold, it is preferable to apply vibration to remove the entrained air bubbles due to the casting and to improve the strength and the shape retention. Vibration amplitude 0.1 ~
5 mm and a frequency of 500 to 50 Hz are preferred.

In this manner, a plurality of types of slurry having different types, particle diameters and addition amounts of the foaming agent are poured into the mold, and in a state after foaming, the porosity, pore diameter or pore shape of each portion is different. A soft structure rich in water is obtained.
In this structure, it is considered that the CSH gel and the remaining coal ash particles form a skeleton.

There is also a method in which a foaming agent is used instead of the foaming agent. In the method of using the foaming agent of the second invention of the present invention, after mixing a predetermined amount of coal ash and a predetermined amount of a calcium compound, water, preferably warm water of 40 ° C. or higher is mixed with a solid content of 20 to 100%. This is a so-called mixed foam method in which a foaming agent is mixed into the slurry mixed with weight% and rapidly mixed to generate air bubbles. The method of using the foaming agent according to the third invention is that, after mixing a predetermined amount of coal ash and a predetermined amount of a calcium compound, water, preferably warm water of 40 ° C. or more is added in an amount of 20 to 100% by weight based on the solid content. In the mixed slurry,
This is a preform method in which fine bubbles are created in advance by a foaming agent and mixed with the fine bubbles.

Examples of the foaming agent include detergents (anionic surfactants such as alkyl allyl sulfonate such as sodium lauryl sulfate and sodium dodecyl benzene sulfonate, alkyl naphthalene sulfonate, and nonylphenoxydiethoxyethyl sulfate); Or nonionic surfactants such as alkyl allyl sulfonic acid, alkyl sulfonic acid naphthalene, polyoxyethylene alkyl ether, polyoxyethylene lauryl ether, fatty acid diethanolamide, polyoxyethylene lanolin alcohol ether, and polyoxyethylene lanolin fatty acid ester ), Botanical or animal colloid, saponin, denatured colloidal naphthalene butylsulfonate, sodium isopropylsulfonate, calcium chloride, alumina cement, other surfactants (polyoxy Polyoxyethylene alkyl amine ether), there are derivatives of proteins such as gelatin casein. In particular, anionic and nonionic surfactants are preferable, and the amount of the foaming agent added is 0.01 to the solid content.
~ 1% by weight is preferred. In addition, it is considered that the structure using the foaming agent is the same as the structure using the foaming agent.

The autoclave curing temperature as a hydrothermal treatment is 120 ° C. or more, preferably 130 to 250 ° C., and the curing time is 2 hours or more, preferably 5 hours or more. The absolute pressure when the saturated steam temperature is 120 ° C. is about 2K
g / cm ² . Autoclave curing temperature is 120 ℃
If it is less than 3, the strength of the light-weight solid is not sufficiently exhibited, the water absorption rate increases, and the dimensional stability against water also deteriorates. It is considered that the reason for this is that in the autoclave curing at a temperature lower than 120 ° C., the generation of tobermorite having an effect of improving the strength is small, and a large amount of calcium hydroxide and calcium silicate which adversely affect the dimensional stability remain. In addition, it is considered that C-S-H gel also has an effect on the deterioration of dimensional stability. In an autoclave curing at a temperature lower than 120 ° C., a large amount of CSH gel remains due to insufficient generation of tobermorite, and water in the CSH gel largely changes depending on the dry-wet state. As a result, it is presumed that the volume of the light-weight solidified material greatly changes as the water enters and exits, and the dimensional stability deteriorates. When the mixing ratio of the coal ash is less than 30% by weight, the dimensional stability tends to be slightly deteriorated.
In addition to calcium silicate, C-S-H gel is considered to have an adverse effect. The autoclave curing is preferably performed after the foaming of the slurry poured into the mold is completed, from the viewpoint of strength and dimensional stability. It should be noted that autoclave curing while immersed in water is not preferable.

The coal ash has a bulk density of 0.8 g / cm ³
Or more is preferable, and 1.0 or more is more preferable. If the bulk density is less than 0.8 g / cm ³ , the strength of the light-weight solidified product is reduced, and the variation in strength is increased. The measurement of the bulk density was based on the measuring method of JIS Z2504. The average particle size of the coal ash is preferably 5 to 40 μm,
More preferably, it is 10 to 30 μm. Average particle size is 5μ
If it is less than m, the strength of the light-weight solidified product will decrease, and if the average particle size exceeds 40 μm, the strength will decrease and the variation in strength will increase. Although the reasons for these are not clear, it is assumed that coal ash is involved in the strength of the light-weight solidified product as aggregate. Therefore, it is considered that coal ash having a low bulk density has many hollow particles of coal ash particles, and tends to easily cause a decrease in strength and an increase in variation in strength. In addition, coal ash having an average particle size of less than 5 μm is less likely to remain as coal ash particles after autoclaving and coal ash is not involved as an aggregate, and thus it is considered that the effect of improving strength is unlikely to be brought about. On the other hand, coal ash having an average particle size of more than 40 μm is considered to be likely to act as a defect because the particle size is too large, though it remains as coal ash particles even after autoclaving. Generally, the lightweight solidified material is mixed with silica sand or the like as an aggregate to improve the strength, but when the lightweight solidified material of the present invention is added with coal ash, the residual coal ash acts as an aggregate,
It is not necessary to add silica sand or the like because it is considered to have a strength improving effect. In addition, regarding the particle size distribution of coal ash,
In terms of improving strength and reducing variation in strength, the average particle size is 1 /
A distribution in which 60% or more of the particles enter 4 to 4 times is preferable. Coal ash is preferably fly ash in terms of strength, but bottom ash can also be used by pulverizing.

Regarding the composition of the coal ash, the aluminum content is preferably 35% by weight or less in terms of Al ₂ O ₃ . It is more preferably at most 30% by weight. Aluminum content is Al
_{When the} content exceeds 35% by weight in terms of ₂ O ₃ , the strength of the light-weight solidified product decreases and the variation in the strength increases. This is considered to be due to the fact that hydrogarnet is easily generated in the coal ash solidified by the autoclave curing, and this acts as a defect. For other compositions of coal ash, S
i component, 30 to 80% by weight in terms of SiO _2, Fe component is preferably 15 wt% or less in terms of Fe ₂ O _3, unburned elementary charge is any problem even 5 wt% or more There is no. The coal ash can be used not only for pulverized coal ash generally generated but also for coal ash generated from a normal pressure or pressurized fluidized bed combustion power generation system.

When the slurry containing the alkali is foamed and then autoclaved, the strength is improved particularly when calcium carbonate is used as the calcium compound. Although the reason for this is not clear, it is presumed that the reaction of the coal ash with the calcium compound is promoted by the presence of the alkali, and the reaction products such as tobermorite are strongly fixed. Examples of the alkali include an alkali metal hydroxide (eg, NaOH, KOH), an alkali metal carbonate (eg, Na ₂ CO ₃ ), and ammonia. Among these compounds, alkali metal hydroxide, ammonia, and alkali metal carbonate are in the order of action and effect. Among these, alkali metal hydroxide is preferable, and sodium hydroxide is particularly preferable. More preferred. The content of the alkali is preferably in the range of 0.001 to 20% by weight, more preferably 0.1 to 10%, based on the weight of the coal ash. A good solid can be obtained.

The slurry poured into the mold is subjected to a curing temperature of 30 to 100 ° C., more preferably 40 to 90 ° C., and a curing time of 1 hour or more, more preferably 3 hours or more, before the autoclave curing. This is preferable from the viewpoint of improving the strength of the light-weight solidified product. In addition, foaming is quickly completed by this curing, and the time required to reach a semi-plastic state (a solid state in which the mold can be removed and cut with a piano wire) is shortened, so that uniformly dispersed pores are obtained, which is preferable. In addition, demolding is possible by this curing, and it is preferable because autoclave curing can be performed in a demolded state. Curing includes wet curing, flooded curing, watering curing, and film curing, but wet curing and flooded curing are more preferred.

The structure foamed in this way is subjected to autoclave curing. In autoclave curing, the generated C
And -S-H gel, residual coal ash particles and react with crystalline tobermorite _{(5CaO · 6SiO 2 · 5H 2} O) is generated and high strength. Ultimately, a large number of pores are dispersed in a matrix containing tobermorite as a main component, coal ash particles and CSH gel, and porosity in each part,
A structure having different pore diameters or pore shapes is obtained, and a high-strength, lightweight solidified product can be obtained.

Accordingly, the thus obtained lightweight multi-layer solidified product has, for example, an absolutely dry bulk specific gravity of 1.2 or less, has high strength despite having many pores therein, and can be used without a reinforcing material. is there. Further, the lightweight multilayer solidified product of the present invention also has sound insulation, heat insulation, and nonflammability. On the other hand, depending on the pore distribution, those having a small water absorption can be obtained, so that those having good dimensional stability against water can be obtained, and can be used in a wet state.

Further, the lightweight multi-layer solidified product of the present invention can also be used as a sound absorbing plate. Generally, a sound absorbing plate having excellent sound absorbing properties has a low strength due to a high porosity (for example, a compressive strength of about 10%).
Kg / cm ² ), so that the steel sheet is put in a support such as an iron frame to compensate for the insufficient strength. The lightweight multi-layer solidified product of the present invention exhibits excellent sound absorbing properties and high strength, and can be used without a support. Therefore, for example, a product having both functions of a wall material and a sound absorbing plate can be integrally manufactured. . Therefore, the number of manufacturing steps can be significantly reduced, so that there is also a cost advantage.

For use as a sound absorbing plate, the absolute dry bulk specific gravity of the lightweight multilayer solidified product is preferably from 0.2 to 0.5. The pores in the solidified product have an average pore diameter of 100 to 1000 μm,
It is preferable that each pore communicates. In order to allow the pores to communicate with each other, it is necessary to set the absolute dry bulk specific gravity of the solidified product to 0.2 to 0.5 and to add the following surfactant to the slurry together with the foaming agent. Examples of the surfactant include polyoxyethylene alkyl ether and salts thereof, polyoxyethylene nonyl phenyl ether and salts thereof, alkylbenzene sulfonate, fatty acid diethanolamide, alkyl sulfate, sulfonate, soap, water glass, resin, Saponin and the like. Further, it is preferable to add a foam stabilizer such as polyvinyl alcohol and methyl cellulose. Further, the light-weight multilayer solidified product of the present invention can be used for earth and wood as a water-permeable sidewalk board.

Although the preferred embodiment of the casting method has been described above, other molding methods such as press molding and extrusion molding can also be performed by ordinary methods.

[0028]

Next, the present invention will be described based on embodiments. (Example) Fly ash having a bulk density of 0.8 g / cm ³ or more and an average particle diameter of 5 to 40 μm as a coal ash (component: SiO ₂ 3)
0-80 wt%, Al ₂ O ₃ 35 wt% or less, while using Fe ₂ O ₃ 15 wt% or less), as a calcium compound, ordinary Portland cement, calcium oxide, calcium hydroxide, calcium carbonate, four After mixing these raw materials and a foaming agent at an appropriate weight, water was added in an amount of 20 to 100% by weight based on the solid content to prepare various coal ash slurry. Aluminum powder and calcium powder were used as the foaming agent, and were added in an amount of 0 to 0.7% by weight based on the solid content. The three different types of mud are placed in a mold (bottom surface 9).
0 × 150 mm) to make three layers, 40-90
Foamed and cured in a wet state at a temperature of ° C for 20 hours. In Examples 1 to 10, each layer was 30 mm, and in Examples 11 and 1,
2 is the first layer 10 mm, the second layer 70 mm, the third layer 10 m
m, Examples 13 and 14 are 20 mm for the first layer and 50 mm for the second layer.
mm, the third layer was 20 mm. Examples 9 and 14
Did not cure and foamed at room temperature. 100 ° C
Autoclave curing was performed at the above temperature for 20 hours.

Next, embodiments will be described in detail with reference to Tables 1 and 2. Example 1 used the first layer: 45% by weight of normal Portland cement, 45% by weight of calcium oxide, and 10% by weight of coal ash without using a foaming agent. The second layer: 45% by weight of normal Portland cement.
And a calcium compound of 45% by weight of calcium oxide and 10% by weight of coal ash, a foaming agent of 0.2% by weight, a third layer: 45% by weight of ordinary Portland cement and 4% of calcium oxide
A 5% by weight calcium compound and 10% by weight of coal ash were used, a blowing agent was 0.35% by weight, and autoclaved at 130 ° C. Example 2 used the first layer: 40% by weight of ordinary Portland cement, 30% by weight of calcium oxide, a calcium compound and 30% by weight of coal ash, and no foaming agent was added. The second layer: 40% by weight of ordinary Portland cement and oxidized 30% by weight of calcium compound and coal ash 3
0% by weight, foaming agent 0.05% by weight, third layer: ordinary Portland cement 40% by weight and calcium oxide 30
Weight percent calcium compound and coal ash 30 weight%,
The foaming agent was 0.19% by weight and autoclaved at 130 ° C. Table 1 and Table 2 below.

Each of the thus obtained coal ash solids (90
× 90 × 150 mm), the external appearance was observed, and the compressive strength and the absolute dry bulk specific gravity were measured. The results are shown in Tables 1 and 2. However, in the observation of the appearance of the coal ash solidified matter, the presence or absence of damage such as cracks in the solidified matter and the strength of morphological retention were judged, and good ones were indicated by ○ and bad ones were indicated by ×. The compression strength is measured by placing a 90 × 90 mm metal plate on the upper and lower surfaces of a rectangular parallelepiped and applying pressure in parallel to each layer.
An autograph was performed according to 1108, and the average of 10 samples was taken as the compressive strength, and the standard deviation was taken as the dispersion. The specific gravity of the lightweight multi-layer solidified product is determined by the absolute dry bulk specific gravity according to JIS.
It was measured according to A 5416. (Comparative Example) As shown in Table 3, the mixing ratio of coal ash is 70 to 8
0% by weight, and three kinds of calcium compounds, ordinary Portland cement, calcium oxide and gypsum, were used.
Note that Comparative Examples 15 to 18 each had a layer of 30 mm, and Comparative Example 19 had a single layer of 90 mm. Others were the same as the example.
In Comparative Example 18, steam curing (20 hours) was performed without performing autoclave curing.

The second and third inventions differ from the first invention in the method of forming bubbles in the slurry, but the solidified product has the same structure as that produced by the method of the first invention. The characteristics are also equivalent.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

As is clear from the above description, according to the present invention, a lightweight, multi-layered solidified material having different pore distributions with high strength and light weight can be obtained, which can be applied to building materials such as building panels and sound absorbing materials. The effect of the invention is extremely great.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-287084 (JP, A) JP-A-5-286780 (JP, A) JP-A-3-193677 (JP, A) JP-A-1- 30745 (JP, A) JP-A-4-169639 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C04B 28/18

Claims (4)

(57) [Claims] 1. A mixture of a raw material, a blowing agent and water comprising at most 90% by weight of coal ash and at least 10% by weight of a calcium compound is prepared, and the mixture is formed into a laminate. A method for producing a lightweight multi-layer solidified product, comprising performing a hydrothermal treatment at a high temperature of 120 ° C. or higher and a high pressure. 2. A plurality of mixtures of a raw material, a foaming agent, and water composed of at most 90% by weight of coal ash and 10% by weight or more of a calcium compound are produced, and these mixtures are formed into a laminate. And a hydrothermal treatment under a high temperature and a high pressure of 120 ° C. or more. 3. A plurality of mixtures of a raw material and water consisting of at most 90% by weight of coal ash and at least 10% by weight of a calcium compound are prepared, and air bubbles previously prepared by a foaming agent are added to each of the mixtures. A method for producing a lightweight multi-layer solidified product, comprising a step of mixing a predetermined amount of the mixture, forming the mixture into a laminate, and then performing a hydrothermal treatment at a high temperature of 120 ° C. or higher and a high pressure. 4. The lightweight multilayer solidified product according to claim 1, wherein the calcium compound is at least one calcium compound selected from the group consisting of calcium oxide, calcium hydroxide, calcium carbonate, and calcium silicate. Method.