JP4485159B2 - Manufacturing method of humidity control material - Google Patents

Description

  The present invention relates to a method for producing a humidity control material.

Two types of boilers are currently used in coal-fired power plants, which are positioned as an important pillar of crude oil alternative energy along with nuclear power in Japan's energy policy. One is a conventionally known pulverized coal boiler, and the other is a fluidized bed boiler. The pulverized coal boiler pulverizes coal containing low sulfur and burns the pulverized coal instantaneously like oil at an ultra-high temperature around 1500 ° C. In addition to carbon dioxide and water vapor, flue gas contains ash called solid component fly ash and NOx and SOx, which are harmful gas components, and are collected and decomposed in the middle of the flue so that they are not released into the atmosphere. is required. Since the recovered ash exceeds the melting point of the ash due to ultra-high temperature combustion, it melts to form a spherical shape like glass beads, and in addition to glassy substances, crystalline substances such as mullite and quartz are small, but glassy. Present in the matrix. Since coal used as pulverized coal can not be the SOx process completely sulfur content is not less than 0.8%, and the use of low sulfur coal is mandatory.

On the other hand, a pressurized fluidized bed boiler is a new boiler that pressurizes the combustion chamber to about 10 to 20 atm to increase power generation efficiency and generates power not only with steam but also with exhaust gas. Recently, this type of plant has been on an increasing trend. is there. A pressurized fluidized bed boiler is capable of burning high sulfur coal. The pressurized fluidized bed boiler mixes massive coal and limestone at the same time, and circulates and burns gently at a low temperature around 850 ° C. Since it is a low-temperature combustion, NOx is not originally generated, and SOx reacts with the mixed limestone and does not go out. During circulating combustion, the ash is in a fine powder state and is also recovered as fly ash. This fly ash has an angular appearance without melting because it is burned below the melting point and does not contain a vitreous substance. For example, hard gypsum <CaSO ₄ >, hydroxyelastate dite <Ca ₁₀ (SiO ₄ ) ₃ (SO ₄ ) ₃ (OH) ₂ >, Portlandite <Ca (OH) ₂ >, Calcite <CaCO ₃ >, Anorthite <CaAl ₂ Si ₂ O ₈ >, Wollastonite etc. <CaSiO ₃ >, Quartz It consists only of the crystalline material <SiO _2> and the like.

It is thought that a coal-fired power plant equipped with such a boiler will be expanded in the future, and it is believed that the amount of coal ash (fly ash) discharged from the coal-fired power plant will increase with this expansion.
Currently, coal ash is effectively used as a raw material for cement and the like, but its utilization rate is as low as about 60%, and development of further effective use of coal ash is required.

By the way, in recent years, a humidity control material has been developed that reduces and stabilizes humidity in a room such as a building or a house, and produces a so-called “smoothness” (Patent Documents 1 and 2).
JP 2001-286723 A JP 2001-123547 A

However, these humidity control materials use natural mineral powders such as allophane, zeolite, and diatomaceous earth as raw materials, and do not use coal ash as a raw material.
In addition, as a humidity control material, it has a humidity control function that maintains a relative humidity of 40 to 70% RH, which is generally considered to be comfortable for humans, and can be used on the walls of houses and buildings. What has a sufficient intensity | strength is calculated | required.
Therefore, the present invention provides a method capable of producing a humidity control material excellent in both humidity control function and strength easily and inexpensively by effectively utilizing fly ash discharged from a coal-fired power plant. For the purpose.

  As a result of intensive studies to solve the above problems, the present inventors have mixed coal ash (fly ash) discharged from a coal-fired power plant, natural zeolite, and an alkali silicate solution at room temperature (approximately 20 By solidifying at ± 1 ° C., it was found that a humidity control material having a humidity control function and a strength comparable to concrete could be produced, and the present invention was completed.

That is, the method of manufacturing a humidity control material according to the present invention is a method of manufacturing a humidity control material in which an active filler and natural zeolite are mixed in an alkali silicate solution , solidified, and molded .
The weight ratio of the natural zeolite to the artificial zeolite produced by the alkali treatment of the active filler in an alkali silicate solution is 1: 9 to 4: 6 .

Before Symbol natural zeolite preferably has a humidity effect of 30 to 50% RH correspond.

A method of manufacturing a humidity material according to the present invention, a natural zeolite, were mixed with fly ash, and the alkali silicate solution, may be characterized in that molded by compression.

  ADVANTAGE OF THE INVENTION According to this invention, the method which can manufacture the humidity control material which has the humidity control effect | action and the intensity | strength comparable to concrete easily and cheaply using the fly ash discharged | emitted from a coal thermal power plant is provided. be able to.

  An embodiment for carrying out the present invention completed based on the above knowledge will be described in detail with reference to examples. First, the manufacturing method of the humidity control material which concerns on this invention is demonstrated. A humidity control material is a porous and stable artificial substance made by reacting quartzite and quicklime.It has excellent durability, and in a humid environment, moisture is sucked into the material, and in a dry environment. It has the function of exhaling moisture from the inside and maintaining a comfortable humidity environment semipermanently.

The humidity conditioner is manufactured by mixing natural zeolite, silicic acid (SiO ₂ ) such as fly ash and metakaolin, inorganic powder of alumina (Al ₂ O ₃ ), and alkali silicate solution, solidifying and molding. can do. The humidity control material can be manufactured by mixing these raw materials because silicic acid (SiO ₂ ) and alumina (Al ₂ O ₃ ) -based inorganic substances are alkali-treated in an alkali silicate solution to produce artificial zeolite, Thus, the metal component contained in the silicic acid (SiO ₂ ) and alumina (Al ₂ O ₃ ) -based inorganic powder is eluted into the alkali silicate solution to produce an inorganic polymer by condensation polymerization of the silicate complex. It is considered that the inorganic polymer (geopolymer) is caused by solidifying a filler (powder substance) such as natural zeolite or artificial zeolite as a binder (see FIG. 1). In addition, as a metal component eluted in the alkali silicate solution, for example, when fly ash is used as a raw material, a slight amount of calcium is included, and when metakaolin is used as a raw material, an aluminum component as a main component is important. It is thought that.

Humidity filler over has nanopores, refers to a powdery material including silicon and aluminum, for example, there is such as a mixture of natural zeolites, artificial zeolites, natural zeolites.

And natural zeolites, mixtures, the mixing ratio of the intensity of the humidity function and concrete parallel holding the RH 40 to 70% is obtained with the artificial zeolite produced by alkali treatment (artificial zeolite: natural zeolite = 9 1 6: 4), and a mixture ratio (artificial zeolite: natural zeolite = in the range of 9: 1 to 7: 3) that provides a humidity control function that maintains 60% RH or less. Those that are mixed are particularly preferable, and those that are mixed at a mixing ratio (artificial zeolite: natural zeolite = 7: 3) that provides a humidity control function that maintains the lowest relative humidity (about 50% RH) are most preferable. .

The powdery substance which the active filler and active ingredient (filler) may contain an inert filler shows little solubility. The active filler is, for example, a powder such as fly ash or metakaolin which is a calcined kaolin, and the inert filler is, for example, a powder such as quartz or hematite. As fly ash, fly ash discharged from a pulverized coal boiler may be used, but it is preferable to use fly ash discharged from a fluidized bed boiler composed of only a crystalline substance. When fly ash discharged from a fluidized bed boiler and fly ash discharged from a pulverized coal boiler are used at the same time, it is necessary to use fly ash mixed in a weight ratio of 7: 3 to 10: 0. It is particularly preferable to use fly ash mixed at a weight ratio of 9: 1 to obtain a humidity control material excellent in both humidity control function and strength.

The natural zeolites, for example, click Rinopuchiroraito, heulandite, mordenite, analcime, and the like can be used Wairakaito excellent can be obtained humidity material, natural with 30 to 50% RH corresponding humidity control function It is preferable to use zeolite.

Regarding the polycondensation solution of a silicic acid complex which is an inorganic polymer (binder) solution , the polycondensation polymer of a silicic acid complex can be produced by simply polycondensing a silicic acid complex as shown in FIG. As shown in FIG. 3, it is more effective to produce by cross-linking a silicate complex using a metal capable of promoting condensation polymerization (calcium or aluminum contained in the active filler) .

  As the monomer source, for example, an alkali silicate solution such as a potassium silicate solution or a sodium silicate solution can be used. However, it is preferable to use a sodium silicate solution, which is particularly inexpensive and has high solidification characteristics. It is preferable to use a sodium silicate solution called No. In addition, as temperature which solidifies a humidity control filler using the inorganic polymer obtained by polycondensing a sodium-silicate solution, the humidity control material of strong intensity | strength is obtained, without blocking the pore of a humidity control filler. It is preferable to carry out at ± 10 ° C.

  As described above, the method for producing a humidity control material according to the present invention uses not only natural zeolite but also fly ash discharged in large quantities from a coal-fired power plant as a raw material, which is useful as an effective utilization technology of these resources. Since it can be solidified at room temperature (20 ± 1 ° C.) without reacting at a high temperature, there is an advantage that production energy can be greatly reduced.

In addition, the humidity control material obtained by the method of manufacturing a humidity control material according to the present invention has a humidity control effect and is light in weight (generally having a bulk density of about 1.5 g / cm ³ ), which is similar to that of concrete. There is a feature that indicates the strength of. Therefore, the humidity control material obtained by the method of manufacturing a humidity control material according to the present invention is in the form of various tiles, panels, boards, bricks, blocks or soil concrete, interior materials such as houses and buildings, underfloor materials, It can be used as a ceiling material, wall material, etc., and it is thought that it can reduce the power consumption of air conditioners etc. in summer, so it can save the power pinch currently considered as a problem, and finally the earth It is expected to contribute to the prevention of global warming.

To express the monolith humidity function, according Kelvin capillary condensable formula shown in FIG. 4, it is reported that it is necessary to concentrate the pore radius 5nm or less. The inventors of the present invention have found that when the PF ash (pressurized fluidized bed boiler ash) -OF ash (pulverized coal boiler ash) -based geopolymer monolith has a large content of PF ash, the pore radius is concentrated at 5 nm or less. It revealed that. In particular, in the monolithization obtained by polymerizing coal ash of PF ash and OF ash (PF ash: OF ash = 9: 1, weight ratio ), a sharp peak concentration was observed at a pore radius of 3.5 nm. In the Arai formula (see Fig. 4), this corresponds to a humidity control capability corresponding to 68% RH, and the measured value also agrees within an error range of 2%.

Zeolite powder (clinoptilolite, CaO—Al ₂ O ₃ —SiO ₂ —H ₂ O system) that is known to have a humidity control function for 40% RH for the purpose of improving the humidity control function based on these data. Natural zeolite; Z) and coal ash of the above PF ash and OF ash (PF + OF 3 , PF: OF = 9: 1, weight ratio ) were mixed at a ratio shown in Table 2 to prepare a monolith sample. As the monomer source, No. 1 sodium silicate solution <Na ₂ O · 2SiO ₂ · aq> was diluted with water twice and the specific gravity was adjusted to 1.27. Table 1 shows the chemical composition and physical properties of the raw materials used in this example. In addition, what was obtained from each boiler was used for coal ash, such as PF ash and OF ash, as it was.

  Mix the ratio of sodium silicate solution and humidity control filler (liquid / solid ratio (P / S)) under the condition of 0.65 to 0.75, pour into a 2 × 7.5 × 10.5cm mold and leave at room temperature. The mold was released after a day, and further cured by being left at room temperature. Each monolith (humidity adjusting material) obtained in this manner was left in a desiccator filled with water, and the lowest humidity reached was read with a hair hygrometer. As a result, after placing the monolith in the desiccator and closing the lid, the humidity drops sharply after about 5 minutes, generally reaching equilibrium after about 6 hours, and maintaining the humidity close to the equilibrium humidity around 6 hours The humidity tended to increase gradually again.

In addition, the relative humidity of each monolith in the 28-day aging material was measured. The results are shown in Table 3.

  As shown in Table 3, PF ash and OF ash coal ash (PF + OF) and natural zeolite (Z) ratio of 7: 3 is the lowest relative humidity (52%) in the monolith made using monolith sample D RH) was obtained, and it was confirmed that it was sufficiently practical.

In addition, bending strength (2 × 2 × 8 cm, 3 pieces) using 1, 3, 7, and 28-day aging materials of each monolith (monolith prepared using monolith samples A to J) obtained in Example 1 I examined the mold form, span distance 5cm, crosshead speed 0.2mm / min). In addition, the bending strength test was performed based on the mortar strength test method of JIS specification. The results are shown in Table 4. In addition, the numerical value in Table 4 is an average value calculated | required based on the data of three samples.

  As shown in Table 4, it is clear that monoliths produced using monolith samples A to E exceeded the general bending strength of concrete, 5 MPa, and monoliths produced using monolith samples D or E in particular exceeded 6 MPa. It became.

  According to Examples 1 and 2, the monolith produced by using the monolith sample D relatively showed excellent results in both humidity control and strength, and applied to a room of a house or building as a humidity control wall. It seems to be able to alleviate the high humidity environment during the rainy season and summer.

It is the figure which showed a mode that the slurry containing a filler solidifies and monolithizes, when a monomer polymerizes by a metal component eluting from a filler (filled powder) in a monomer solution, and pours into a casting_mold | template. It is a figure which shows the production | generation of the silica gel by the polycondensation of a silicic acid complex. It is a figure which shows the production | generation of the inorganic polymer by the condensation polymerization which uses a metal as a bridging atom, and the production | generation of an organic polymer. Kelvin capillary condensable formula and Kelvin - is a diagram showing a Arai expression.

Claims (5)

An active filler and a natural zeolite are mixed in an alkali silicate solution , solidified and molded to form a humidity control material,
The weight ratio of the natural zeolite to the artificial zeolite produced by the alkali treatment of the active filler in an alkali silicate solution is 1: 9 to 4: 6. . The method for producing a humidity control material according to claim 1 , wherein the weight ratio of the natural zeolite to the artificial zeolite is 3: 7 . The said active filler contains a fly ash or metakaolin, The manufacturing method of the humidity control material of Claim 1 or 2 characterized by the above-mentioned. The said natural zeolite has the humidity control effect | action corresponding to 30-50% RH, The manufacturing method of the humidity control material of any one of Claims 1-3 characterized by the above-mentioned. A method for producing a humidity control material, comprising mixing natural zeolite, fly ash, and an alkali silicate solution, solidifying and molding.

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