JP2002348170A - Manufacturing method of humidity adjustment material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a humidity adjustment material whose raw materials can be stably collected and as well as the usage of natural minerals as raw materials can be reduced the before. SOLUTION: A mixture of raw materials including a fly ash, a Ca simple substance or Ca compound is kneaded with water, hardened at a temperature of 0-260 deg.C, under atmospheric pressure-2.5 MPa. The content of the fly ash in the mixture of raw materials is preferably 20-95 wt.%.

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 humidity control material, and more particularly, to a method for producing a useful humidity control material by effectively utilizing fly ash generated secondary from a thermal power plant or the like. About.

[0002]

2. Description of the Related Art In recent years, for the purpose of energy saving and improvement of living environment, high airtightness of buildings has been aimed at, and development of new building materials and technologies for improving building structures has been promoted. However, the high airtightness of a building, on the other hand, increases the dew condensation on the surface of indoor building materials, which is a cause of deterioration in indoor habitability and durability of the building. In addition, moisture generated by condensation promotes the generation of molds and mites, and there is a concern that those substances may adversely affect the human body.

As one of the countermeasures, it is conceivable to control the indoor atmosphere by indoor air conditioning, but the cost of electric power used as power for air conditioning is relatively high.
For this reason, indoor air conditioning is not used in rooms without people, and there is also a problem of environmental deterioration due to heat radiation outside,
It is not the best solution.

[0004] Therefore, there is a demand for a technology for adjusting the humidity in the room without using power to prevent the deterioration of the living environment, and the development of a humidity control material has been vigorously developed due to such needs. Here, humidity control refers to a function of sucking moisture into a material in a humid environment and discharging moisture from the inside in a dry environment to realize a comfortable humidity environment. The substance itself has this humidity control action. The humidity control material is used as an interior material of a house, an underfloor material, a ceiling material, a wall material, or the like in the form of various tiles, panels, boards, bricks, blocks, or concrete between slabs. Further, there is also a case where a powdery and humidity-controlling material is filled in a space provided under a floor, a ceiling, or a wall while being packed in a bag or in a powdery state. For example, JP-A-11-171662 discloses that
Disclosed is a technology for manufacturing a heat insulating structure using porous coal and inorganic mineral powder as materials, in which a building material having air permeability, air intake, odor absorption, moisture absorption, etc., by the action of non-combustible porous coal. Has been proposed. Also, Japanese Patent Application Laid-Open No. H11-315586
The official gazette mixes volcanic pumice layers, diatomaceous earth, humidifying raw materials such as zeolite and glassy components such as clay and feldspar,
It discloses a technique of baking after molding to obtain a humidity control material.

[0005]

However, in the heat insulating structure described in Japanese Patent Application Laid-Open No. 11-171662, examples of non-combustible carbide as raw materials include food production residues, rice hulls, pruned branches, and animals and plants. Although the flammable substance is formed in its original form or shaped into a desired particle size, it is quite difficult to stably and surely collect those. As a result, the raw materials change with each production,
It has been very difficult to maintain the heat insulating effect and the moisture absorbing effect of the heat insulating structure as the final product at a certain level or higher.

The humidity control building materials described in Japanese Patent Application Laid-Open No. 11-315586 are mainly made of a humidity control raw material such as volcanic pumice layer, diatomaceous earth and zeolite, and a natural mineral such as a glassy component such as clay and feldspar. Therefore, there was a problem in terms of environmental destruction due to raw material mining.

[0007] In view of such circumstances, an object of the present invention is to provide a method for producing a humidity control material capable of not only stabilizing the collection of raw materials but also reducing the amount of natural mineral used as a raw material as compared with the conventional method. I have.

[0008]

Means for Solving the Problems In order to achieve the above-mentioned object, the inventor has worked diligently to find a new substance which is a raw material of a humidity control building material, and a large amount of secondary substances is generated from a thermal power plant or the like. I focused on fly ash. This is because various effective means have been devised so far, but even now, about half of the generated amount is discarded by landfill or the like. This fly ash is difficult to use effectively,
The average particle size of fly ash is very fine, several tens of μm, the curing reaction at room temperature is slow, and there is a possibility of environmental impact such as elution of metal. This is because, in fly ash, crystalline and amorphous relatively stable SiO ₂ as a main component, an acidic oxide such as Al ₂ O ₃ , a small amount of a basic oxide such as CaO and MgO, and a trace amount of heavy metal This is because various components are contained.

Therefore, the inventor paid attention to the fact that such fly ash contained SiO ₂ as a main component, and developed a technique for producing a solidified product based on this SiO ₂ . It has been found that if fly ash is appropriately blended with various slags containing Ca generated in an iron mill and cured and maintained in a predetermined atmosphere, a useful humidity control material can be produced, and the present invention has been completed. It is.

[0010] That is, the present invention relates to fly ash
a. A raw material mixed with a substance containing a simple substance or a Ca compound is kneaded with water, and then 0 to 260 ° C., atmospheric pressure to 2.5 M
This is a method for producing a humidity control material, which is cured under a pressure of Pa. In this case, the blending amount of fly ash in the mixed raw material is 20 to 95% by mass, or the substance containing the Ca compound is molten iron pretreatment slag, converter slag, smelting reduction furnace slag, and stainless steel refining slag. And one or more selected from blast furnace slag.

According to the present invention, even when fly ash is used as a main raw material, the addition of a Ca-containing substance promotes the formation of a Si-Ca hydrate phase, thereby providing a good humidity control material.
The reason why the humidity control material is not used as the humidity control building material here is that not only blocks or panels but also powdery materials are included.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described along the history of the invention.

Fly ash is generally SiO ₂ , Al ₂
O ₃ is the main component.

First, the inventor mixed fly ash with a Ca-containing substance such as steelmaking slag and reacted it in the presence of water. In such a SiO ₂ —CaO—Al ₂ O ₃ —H ₂ O system, , tobermorite phase (5CaO · 6SiO ₂ · 5H ₂
O) and other Si-Ca hydrate phases were found to be stably present. And the S generated by this hydration reaction
The i-Ca hydrate phase increases the strength of the solidified body (because the mixed raw material is put in a container and kneaded with water and then solidified, so hereinafter, referred to as a molded body), and acts only favorably on the solidification of the molded body. It also has a humidity control effect, so it could be used as a humidity control material for construction and civil engineering.

Therefore, the inventor has continued his research,
In order to generate these Si-Ca hydrate phases, a mixture containing fly ash as a main raw material and other substances is formed into a predetermined shape in the presence of water, and is subjected to 0 to 260 ° C. and normal pressure. Or, it was found that curing at high pressure is sufficient. in this case,
As a specific means of heating under high pressure, it was suitable to use an autoclave. The autoclave is a pressure vessel in which, when water is put into a vessel and the temperature is raised, the pressure of the internal atmosphere is automatically increased due to a closed system. Therefore, when the temperature of the container is increased with water therein, the vapor pressure (saturation pressure) is 1 atm at 100 ° C., but when the temperature is further increased, the vapor pressure further increases. Heating under such high pressure steam significantly increases the reaction rate of the substance. The important point of the present invention is that
By utilizing this reaction promoting action, fly ash is reacted with a substance containing Ca to produce a tobermorite phase useful for a humidity control action.

In the above operation, the amount of water is adjusted, a large amount of water is mixed with the above mixture, and the mixture is cured at 0 to 260 ° C. at normal pressure or high pressure, so that fly ash reacts with the substance containing Ca. As a result, a slurry is formed in which the particulate matter that has produced the tobermorite phase is mixed with water.

As for the water content, when the mass of a mixture of fly ash as a main raw material and other substances is taken as 100, about 10 to 100 parts by weight of water is added and mixed, the mixture is shaped into a predetermined shape. By curing, a humidity control material having the predetermined shape can be obtained. Therefore, the target building material can be directly manufactured by forming into the shape of a building material such as a panel or a board and performing the curing. Such a building material can be used as it is by heating it to room temperature or about several tens of degrees Celsius and drying it. This drying step does not need to be performed as a special operation step, and the drying starts when the curing step is completed and taken out at normal temperature and normal pressure.

Assuming that the mass of a mixture obtained by mixing fly ash as a main raw material and other substances is 100, if water is added in excess of 100 parts by mass and mixed,
A slurry-like material that does not have a fixed shape even after curing is obtained. Even in this case, the granular material forming the slurry is the granular material that has produced the above-mentioned tobermorite phase, and is a material having humidity control properties. Therefore, a humidity control material can be obtained by drying this slurry. Since this slurry can be formed into an arbitrary shape by being put in a mold and dried, it is suitable for producing a large-sized building material that cannot fit in the autoclave as described above.

Further, when a slurry-like powdery or granular substance is spray-dried using a spray dryer or the like, a powdery or particulate humidity control material can be produced. The particulate humidity control material can be usefully used as a building material by a method such as bagging or filling in a frame. The particulate humidity control material can also be manufactured by crushing a molded body that has been molded into a predetermined shape and cured as described above. In the production of a powdery and moisture-conditioning material by spray drying, particles of several tens of μm to several mm can be obtained. However, in the case of manufacturing by crushing a compact, it is necessary to perform It is also possible to produce a moisture conditioning material in the form of a powder of about 10 mm.

Here, according to the study of the inventor, Si—C
The amount of fly ash suitable for producing the a hydrate phase is 95 to 20 mass% of the whole mixed (blended) raw material.
Met. More preferable blending amount is 80 to 20 m in total.
ass%. If the amount of fly ash exceeds the above upper limit or does not fall below the lower limit, sufficient Si-Ca
This is because a hydrate phase is not generated, and sufficient humidity control performance and molded article strength cannot be obtained.

The curing temperature is from 0 to 260 ° C.
preferable. If the temperature is lower than 0 ° C, the added water
Si-Ca hydrate phase that coagulates and develops humidity control
This is not preferred because the reaction for the formation of the compound hardly proceeds.
In addition, curing is performed at a processing temperature exceeding 260 ° C.
And the tobermorite phase is a zonotolite phase (CaO.SiO
_Two・ H_TwoThe reaction for producing O) is remarkably accelerated. Zonoto
The light phase has no problem with hygroscopicity,
Since the strength is not sufficient, it is necessary to manufacture molded products.
In this case, it is not preferable.

In the high-temperature and high-pressure treatment, it is preferable to use an autoclave to set the treatment temperature to about 120 to 260 ° C. More preferably, the processing temperature is 160-2.
About 30 ° C. is recommended. The higher the processing temperature, the higher the Si-
The formation of the Ca hydrate phase is promoted, but under the conditions of 120 ° C. or higher, the formation reaction of the tobermorite phase is further promoted,
Particularly, at a temperature of about 160 to 230 ° C., a product having high strength can be obtained in a short time. For this reason, it is particularly suitable for curing the molded body. At a temperature exceeding 230 ° C., the formation of the zonotolite phase described above slightly progresses, but under conditions up to about 260 ° C. or less, a material mainly composed of a tobermorite phase can be obtained, and both humidity control properties and strength are suitable. Building materials can be manufactured.

Further, in the present invention, the appropriate particle size of the particulate Ca-containing substance to be reacted with fly ash is preferably 5 mm or less, more preferably 2 mm or less. If the particle size is larger than 5 mm, the reaction is difficult to be promoted even in the presence of steam mixed with fly ash, so that the strength of the molded body does not increase. As the powdered calcium-containing material, Ca may be used alone, but CaO and Si are mainly used as blast furnace slag and steelmaking slag.
It has been found that substances containing O ₂ can be used. The steelmaking slag in this case includes hot metal pretreatment slag,
Converter slag, smelting reduction furnace slag, stainless steel smelting slag, and the like are equivalent.

A molded article made of the above-mentioned material has appropriate strength as a molded article and also has a humidity control action, so that it can be effectively used as a humidity control building material. In particular, since fly ash and a substance containing Ca can be easily formed into various shapes by mixing and pouring with water, it is molded as a building material for various uses such as various tiles, panels, boards, bricks, blocks, and the like. ,Available. Also, if it is cast at a construction site and cured at normal temperature and normal pressure, it can be suitably used for applications such as clay concrete.

Further, since the powdery and particulate humidity control material made of the above-mentioned material is in the form of powder and granules and has a humidity control action, it can be filled into a floor, a ceiling or a wall in a bag or in a powdery form. Accordingly, the apparatus can be installed in various shapes, and the atmosphere in the building can be humidified.

[0026]

(Example 1) A predetermined amount of fly ash and slaked lime having the component compositions shown in Table 1 were weighed, water was added and mixed, and the mixture was poured into a stainless steel container (mold) and molded. Curing was performed at various treatment temperatures and times. Table 2 shows the blending amounts and curing conditions of the mixed raw materials in which fly ash and slaked lime were blended. The amount of water added to the raw materials is
Although it differs depending on the mixing of the mixed raw materials, it has a degree of fluidity enough to be poured into the mold. Here, when the curing temperature is lower than 100 ° C., the curing is performed in a thermostat,
Those having a temperature of not lower than ℃ were cured in an autoclave.

[0027]

[Table 1]

[0028]

[Table 2]

The molded articles obtained by these curing treatments have a specific gravity of JIS R 2205 and a flexural strength of JIS R 2205.
It was measured by a method according to R 2553, and the results are shown in Table 2 collectively. The humidity control performance of the molded body was as follows: the humidity in the tank maintained at 20 ° C. and 50 RH (abbreviation of relative humidity)% was increased to 90 RH%, the weight change at that time was measured, and the moisture absorption per surface area was measured. It was evaluated by calculating. After maintaining at 90 RH% for 24 hours, the humidity in the tank was returned to 50 RH%, and the weight change was measured in the same manner.
In addition, the same measurement was performed about the commercially available humidity control tile as a comparison. FIG. 1 shows the change over time in the obtained moisture absorption.

As shown in Table 2 and FIG. 1, according to the present invention, a molded product obtained by heat-curing a composition containing fly ash as a main raw material under high-pressure steam is particularly suitable for the mixing ratio of fly ash, curing time, autoclave treatment, and the like. It is evident that those treated at an appropriate temperature range have a good solidification state (specific gravity of 1.1 or more, flexural strength of 8 MPa or more) and humidity control performance (equivalent to or more than a commercially available humidity control tile). (Example 2) Next, steelmaking slag and fly ash having the component compositions shown in Table 3 were weighed in predetermined amounts, water was added and mixed, and the mixture was poured into a stainless steel mold. And autoclaved at various processing temperatures and times. Table 4 shows the amounts of these mixed raw materials and the curing conditions. Note that the amount of water added to the mixed raw material varies depending on the blending of the mixed raw material, but has a degree of fluidity enough to be poured into the mold.

[0031]

[Table 3]

[0032]

[Table 4]

The molded articles obtained by these curing treatments have a specific gravity of JIS R 2205 and a flexural strength of JIS R 2205.
It was measured by a method according to R 2553, and the results are shown in Table 4 collectively. Further, the humidity control performance of the molded product is as follows: the humidity in the tank maintained at 20 ° C. and 50 RH% is 90 RH.
%, The weight change at that time was measured, and the amount of moisture absorption per surface area was evaluated. Also, 90R
After maintaining at H% for 24 hours, the humidity in the tank was returned to 50 RH%, and the weight change was measured in the same manner. In addition, the same measurement was performed about the commercially available humidity control tile as a comparison. FIG. 2 shows the change over time in the obtained moisture absorption.

According to Table 4 and FIG. 2, the compact obtained by solidifying the mixed raw material obtained by mixing the powdery and granular steelmaking slag and fly ash in accordance with the present invention has a good solidified state (specific gravity of 1.1 or more, compaction). It is clear that it has a strength of 20 MPa or more and a humidity control performance (equivalent to or more than a commercially available humidity control tile). (Example 3) A predetermined amount of fly ash and slaked lime having the component compositions shown in Table 1 were weighed, water was added and mixed, and the mixture was poured into a stainless steel container (mold), and various treatment temperatures and treatments were performed. Cured in time. Table 2 shows the amounts and the curing conditions of the mixed raw materials in which fly ash and slaked lime were mixed. Note that the amount of water added to the mixed raw material varies depending on the blending of the mixed raw material, but has a degree of fluidity enough to be poured into the mold. Further, the obtained slurry substance was dried by a spray drying method to obtain a powdery sample.

The humidity control performance of the solidified body obtained by these curing treatments was evaluated by measuring a saturated water supply. Measurement method, 20 ° C, 50RH (short for relative humidity)
%, 70 RH%, 90 RH%
Place it for about a day and fully saturate at each relative humidity,
The weight was measured, and finally water was removed by degassing for 24 hours, and the amount of water absorbed per unit weight was calculated by the following equation. (Saturated water absorption at each relative humidity: unit%) = {(maximum weight at each relative humidity)-(weight after degassing)} x 10
0 × (weight after degassing) The saturated moisture absorption at each relative humidity is shown in Table 5.

From these Tables 2 and 6, it can be seen that the molded product obtained by heat-curing the composition using fly ash as a raw material under high-pressure steam according to the present invention has, inter alia, the mixing ratio of the fly ash, the curing time, the autoclave treatment. It is evident that those treated at an appropriate temperature range have humidity control performance (commercially available humidity control tiles, diatomaceous earth or better).

[0037]

[Table 5]

[0038]

[Table 6]

(Example 4) Next, blast furnace slag, steelmaking slag, fly ash, and slaked lime having the component compositions shown in Table 3 were weighed in predetermined amounts, and water was added and mixed.
It was poured into a stainless steel mold, molded in the same manner as in Example 1, and autoclaved at various processing temperatures and times. Table 6 shows the amounts of these mixed raw materials and the curing conditions. Note that the amount of water added to the mixed raw material varies depending on the blending of the mixed raw material, but has a degree of fluidity enough to be poured into the mold. Further, the obtained molded body was ground in a mortar to a particle size of 2 mm or less.

The humidity control performance of the powdery and granular humidity control material obtained by these curing treatments was evaluated by measuring a saturated water supply amount. The measurement method is as follows. A sample is placed for about 7 days in a tank maintained at 20 ° C., 50 RH (abbreviation of relative humidity)%, 70 RH%, and 90 RH%, and is sufficiently saturated at each relative humidity, and then weighed. The water absorption was removed by measuring and finally degassing for 24 hours, and the water absorption per unit weight was calculated by the following equation. (Saturated water absorption at each relative humidity: unit%) = {(maximum weight at each relative humidity)-(weight after degassing)} x 10
0 × (weight after degassing) The saturated moisture absorption at each relative humidity is shown in Table 6.

From these Table 6, it can be seen that the powdery and granular humidity control material produced from the raw material in which the powdery and granular slag and fly ash are blended according to the present invention has good humidity control performance (commercially available humidity control tile,
Diatomaceous earth).

[0042]

As described above, according to the present invention, fly ash and granular steelmaking slag can be used as a useful inorganic material, particularly as a raw material of a humidity control material. As a result, fly ash, which has been conventionally treated as industrial waste, can now be used as a building material and civil engineering material having humidity control performance, and the present invention contributes to resource reuse, environmental improvement, and the like. However, it is extremely large.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change over time in the amount of moisture absorption of a humidity control material according to the present invention.

FIG. 2 is a diagram showing a change over time in the amount of moisture absorption of a humidity control material according to the present invention, which is different from FIG.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) E04B 1/64 B28B 11/00 A (72) Inventor Masato Takagi 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Pref. F term (reference) in the company's technology research laboratory (reference) CA43 DA03 FA03 FA21 FA25 FA34 FA35 FA37

Claims (3)

[Claims] 1. A mixed raw material in which fly ash is mixed with a substance containing Ca alone or a Ca compound is kneaded with water, and then cured at 0 to 260 ° C. under a pressure of atmospheric pressure to 2.5 MPa. Method of producing a humidity control material. 2. The method for producing a humidity control material according to claim 1, wherein the blending amount of fly ash in the mixed raw material is 20 to 95% by mass. 3. The material containing a Ca compound is one or more selected from hot metal pretreatment slag, converter slag, smelting reduction furnace slag, stainless smelting slag, and blast furnace slag. The method for producing a humidity control material according to claim 1.