JP2001220206A - Method of crush treatment for cement molding waste and method of recycling cement molding waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of crush treatment for cement molding wastes enabling the superfine pulverization by the crush treatment of the waste of a fibrous matter-containing cement molding and the recycling the pulverized matter obtained by the crush treatment as at least a part of the raw material for a cement molding, and a method of recycling. SOLUTION: The method of crush treatment comprises the wet crushing of the waste of the fibrous matter-containing cement molding in a specific aqueous solvent to perform the superfine pulverization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of crushing waste cement molded products and a method of recycling waste cement molded products using the crushing method.

[0002]

2. Description of the Related Art Conventionally, cement molded products have been used for building materials,
In particular, they are used as interior and exterior materials for buildings. This cement molded product is, for example, kneaded by adding water to a composition composed of a cementitious raw material, asbestos for reinforcement (asbestos), and other compounding agents such as a plasticizer, to form a mortar,
Extrusion molding is performed by an extrusion molding machine such as a vacuum molding machine. Here, the yield of such a cement molded product varies depending on the molding method, but is about 75 to 85% by weight based on the weight of all raw materials in the manufacturing process. Then, of the remaining about 15 to 25% by weight of the waste material portion, dust generated by shaving for dimensional adjustment and the like and defective products unsuitable as products have a Blaine specific surface area of 1000 to 3,500.
Ordinary scrap waste ground to about cm ² / g is reused by returning it to the raw material at a rate of about 10% by weight based on the total raw material weight. However, the above 15-
If 25% by weight of the waste material is used as a part of the raw material, quality deterioration such as a decrease in strength occurs. Therefore, the entire waste material is not returned to the manufacturing process. Above all, in the case of the waste material of the molded article itself containing a fibrous substance harmful to the human body such as asbestos for reinforcement, there is a possibility that harmful dust may be generated simply by performing the dry pulverization treatment, Since no effective pulverizing technology has been established for those that contain fibrous materials and are difficult to pulverize, many of them have to be discarded without recycling. Therefore, development of a technology that can effectively use more waste materials of these cement molded products has been awaited.

[0003]

Therefore, in light of the above circumstances, as a result of intensive studies, it has been found that there is a material which contains a fibrous material which is difficult to be crushed by a specific wet crushing method and which can be ultrafinely powdered. Have found that reusing as a part of raw materials for producing a cement molded product leads to an improvement in strength, and have completed the present invention. That is, the present invention makes it possible to pulverize waste cement molded products containing fibrous materials such as asbestos and so on into ultrafine powder, and reuse the ultrafine powder obtained by the pulverization process as a raw material for cement molded products. It is an object of the present invention to provide a method for crushing waste cement molded articles containing a fibrous material and a recycling method using the crushing method. An object of the present invention is, in particular, to eliminate the disposal processing by reusing what has been disposed of in the above mode.

[0004]

Means for Solving the Problems In order to achieve the above object, a pulverizing treatment method according to the present invention comprises wet pulverizing waste cement molded products containing fibrous materials in an aqueous medium to ultrafine powder. Features. By performing wet grinding in an aqueous medium, dust that is harmful to the human body is not generated during the grinding process. Further, by ultra-fine pulverization, it is possible to reuse waste materials of cement molded articles including fibrous materials. The method for pulverizing waste cement molded products according to the present invention is preferably performed in the presence of a dispersant. This is because the presence of the dispersant makes the powder uniformly dispersed in the aqueous medium, so that the powder is easily micronized, and becomes a slurry containing an ultrafine powder having a low viscosity even at a high concentration.

[0005] Another aspect of the present invention is a method of recycling waste cement molded products containing fibrous materials as a form of use of the above-mentioned pulverizing method. An aqueous medium is added to the mixture, and the resulting mixture of the cement molded product waste material and the aqueous medium is wet-pulverized into ultrafine powder, and the obtained ultrafine powder is used as at least a part of raw materials in the production of a cement molded product. Here, the ultrafine powder referred to in the present invention means that the average particle size is 2
It refers to a powder of μm or less. In addition, a slurry in which ultrafine powder is dispersed in an aqueous medium is also included.

[0006] In the pulverization in this recycling method, it is preferable to add a dispersant after the addition of the aqueous medium, and then perform wet pulverization. This is for preventing secondary aggregation and improving the pulverization efficiency. For the same purpose, after adding a dispersant to the aqueous medium, the aqueous medium may be added to the waste cement molded product, and the resulting mixture of the waste cement molded product and the aqueous medium may be wet-pulverized.

[0007] Waste cement-formed products containing fibrous materials which are the object of the present invention include, for example, cement-based extruded products, cement-based paper-formed products, and cement-based press-formed products containing fibrous materials harmful to the human body such as asbestos. Waste materials such as products, and specific examples include building material products including building interior and exterior materials such as slate boards, cement fiberboards, tiles, outer walls, inner walls and fireproof coatings, finishing mortars, and the like. In the present invention, waste materials coming out of a manufacturing site, a construction site, and a dismantling site of these cement molded products are particularly targeted. Examples of the fibrous material contained in the cement molded product include mineral fibers such as the above asbestos and rock wool, and glass fibers. Cement molded articles including those that are difficult to grind, such as steel fibers, carbon fibers, and synthetic fibers, are not preferred as targets. Cement molded articles containing a natural aggregate having a particle diameter of more than 5 mm are also not preferable because they are difficult to grind. The waste material of a cement molded article containing a fibrous material as referred to in the present invention refers to crushed pieces, coarsely crushed materials, powders and other lumps of the above waste material. Cement molded products used by recycling these waste materials include those described above,
It is not limited to this. Examples of the aqueous medium include aqueous solutions containing various dispersants and aqueous solutions containing various grinding aids.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for pulverizing waste cement molded products containing fibrous materials and the method for recycling waste cement molded products using the pulverization method according to the present invention, the waste cement molded product is treated in an aqueous medium. And wet grinding. FIG. 1 schematically shows the procedure of one embodiment of the present invention.
It is. First, a cement molded product such as a cement-based extruded plate containing asbestos or pulp fiber obtained as waste material in the production process 100 is subjected to a primary pulverization in a primary pulverization step 101 to perform a pretreatment. Here, in order to increase the pulverization efficiency in the wet pulverization, it is preferable to previously set the method to about 300 μmPass, and more preferably to 100 μmPass.
Here, a dry pulverizer such as an ordinary ball mill or vertical mill can be used. When the waste material of the cement molded product obtained in the production process 100 is somewhat fine, the primary pulverization process 1
01 can be omitted. Next, the manufacturing process 10
In the waste material of the cement molded product obtained in Step 0 or the waste material of the primary pulverized cement molded product obtained in the primary grinding step 101, the aqueous medium has a weight ratio (cement molded product waste material / aqueous medium) of 70/30. 〜１０10 / 90, preferably 60/4
0 to 20/80 (step 10
2). The mixing ratio between the cement molding waste material and the aqueous medium is 1
If the ratio is less than 0/90, precipitation tends to occur, and a uniform concentration cannot be maintained. Absent. As the aqueous medium, tap water is preferably used, but purified water, recovered water, or the like may be used.

Next, a dispersant is added as a solid component in an amount of 0.01 to 5 parts by weight, preferably 0.01 to 0.7 parts by weight, per 100 parts by weight of the waste cement molded product (step 103). The dispersant having an amount in the above range may be dissolved in an aqueous medium in advance and mixed with the cement molding waste material. In this case, mixing is performed such that the weight ratio of the cement molded product waste material and the aqueous medium after the mixing in the step 103 (cement molded product waste material / aqueous medium) becomes the above-mentioned weight ratio. Also,
The entire amount of aqueous medium can be added in step 103, and step 101 can be omitted. The dispersing agent is introduced for uniform pulverization and uniform mixing to prevent agglomeration of particles in the slurry and to facilitate ultrafine pulverization.

Then, wet pulverization is carried out by a conventional method (Step 1).
04). The wet pulverization may be a batch type or a continuous type, and it is preferable to use a pulverizing device such as a mill using a pulverizing medium such as a sand mill, an attritor, and a ball mill. Among these pulverizers, a wet media stirring mill is particularly preferable. The wet medium agitating mill is a device for moving a medium by vibrating the mill to apply a shearing force, an impact force, a frictional force, and the like to a sample to pulverize the sample. By such wet pulverization, an ultrafine powder having an average particle size of 2 μm or less, preferably 1 to 0.3 μm is obtained.

[0011] The obtained ultrafine powder is produced in the same molding process 100 as the waste material of various cement moldings that are the source of the ultrafine powder.
Or used for the manufacture of other cement products. The ultrafine powder is in the form of a slurry obtained by wet pulverization. Since the cement molded article is formed by adding water from the beginning, the ultrafine powder may be returned to the production process 100 in a slurry state containing water.
In the case of extrusion molding or the like, a kneaded product having a small water / powder ratio is obtained. Therefore, it is necessary that the ratio of the waste material / water medium of the cement molded product in the waste material slurry of the cement molded product obtained in the wet pulverizing step 104 has a solid content concentration suitable for the purpose. As described above, since the pulverized product is obtained as an ultrafine powder having an average particle size of 2 μm or less, preferably an average particle size of 1 to 0.3 μm, it serves as a so-called microfiller. In addition, since the unreacted silica particles contained in the waste material are ultra-pulverized, the raw material can be a material having high reactivity with cement. In this way, one of the raw materials which has a filling effect with respect to the compressive strength is obtained by pulverizing the waste cement molded product, which was simply disposed of as waste material in the manufacturing process, into a fine powder by a specific grinding method. It can be reused alone as an ultrafine powder material that is reactive to a part (microfiller) or cement, or together with a powder that has been reused as a raw material powder. When returning the ultrafine powder, it is preferable to return the raw material at a rate of 10 to 25% by weight based on the total amount of the pure raw material not including the recycled portion among the raw materials of the cement molded product.

The dispersant added in step 102 in FIG. 1 is preferably an organic dispersant because of its high effect of lowering the viscosity. Specifically, a water-soluble cationic surfactant and a water-soluble anionic surfactant are preferable. Surfactants and water-soluble nonionic surfactants can be mentioned. These dispersants can be used alone or in combination of two or more. Among them, an anionic dispersant is preferable. More specifically, examples of the dispersant usable in the present invention include JP-A-5-263010 and JP-A-7-63010.
The following compounds described in JP 300568 or JP-A-10-176079 can be mentioned.

Water-Soluble Cationic Surfactants The water-soluble cationic surfactant used as an organic dispersant includes a tertiary amine salt type cationic low-molecular or high-molecular surfactant and a quaternary ammonium salt. Type cationic low molecular or high molecular surfactants. These dispersants can be used alone or in combination of two or more.

The water-soluble anionic surfactant used as the organic dispersant includes a low molecular weight compound having a carboxylate, a sulfate, a sulfonate and a phosphate as a functional group. Polymeric surfactants can be mentioned. These dispersants can be used alone or in combination of two or more. Examples of the low-molecular carboxylate that can be used as the low-molecular surfactant include higher fatty acid salts such as sodium laurate, sodium stearate and sodium oleate, higher alcohol polyethylene oxide ether acetate, perfluoroalkyl carboxylate, and the like. Can be mentioned. As the polymer carboxylate that can be used as the polymer surfactant, for example, a polyacrylate, a polyacrylic acid-maleic acid copolymer salt or the like of a carboxylic acid monomer alone or at least two or more Or a salt thereof, a copolymer of a vinyl compound and a carboxylic acid monomer or a salt thereof, and carboxymethyl cellulose. Examples of the low molecular sulfates that can be used as low molecular surfactants include higher alcohol polyethylene oxide sulfates, sulfated oils, sulfated fatty acid esters, sulfated fatty acids, sulfated olefins, and alkylphenol polyethylene oxide sulfates. And the like.

Among the above water-soluble anionic surfactants, in order to obtain a high-concentration slurry at the time of wet pulverization, a high molecular weight surfactant is preferable, and polyacrylic acid or a salt thereof is particularly preferable. A carboxylic acid monomer such as a polyacrylic acid-maleic acid copolymer or a salt thereof may be used alone, or a copolymer composed of at least two or more of them or a salt thereof. These molecular weights are not particularly limited, but are preferably 1000 to 1000.
00, more preferably 5,000 to 50,000.

Water-soluble nonionic surfactants The water-soluble nonionic surfactants used as organic dispersants include polyethylene glycol type water-soluble nonionic surfactants and polyhydric alcohol type nonionic surfactants. Can be mentioned. These dispersants can be used alone or in combination of two or more.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Pulverization method Example 1 Weight ratio of pulverized waste material (average particle size: 0.2 mm) of cement extruded plate (wall material) containing about 10% by weight of fibrous materials such as asbestos and pulp to water And 45 parts by weight of water, and 0.3 parts by weight of an anionic dispersant [SN-2X6301 (specially modified polyacrylic acid salt) manufactured by San Nopco Co., Ltd.] is added per 100 parts by weight, and a table-type medium stirring is performed. Using a mill, zircon balls having a diameter of 0.5 to 2.0 mm, a filling rate of 10 to 20% by volume, and a peripheral speed of 150 to 2
Wet pulverization at 00 revolutions / minute, average particle size 1.08 μm (D
₅₀ ) An ultrafine slurry was obtained.

Example 2 A weight ratio of waste material to water of a cement press molded product (roof material) containing about 15% by weight of a fibrous material such as asbestos was 40.
/ 60, and water was added to the mixture to obtain an anionic dispersant [Dispersant 5 manufactured by San Nopco Co., Ltd.] per 100 parts by weight.
027 (sodium polycarboxylate)] and a diameter of 0.5 to 0.5% using a table-type medium stirring mill.
Ultrafine powder slurry having an average particle size of 1.18 μm (D ₅₀ ) was obtained by wet grinding with 2.0 mm silica sand at a filling rate of 10 to 20% by volume and a peripheral speed of 150 to 200% by volume.

2. Recycling Method Example 3, Comparative Examples 1 and 2 The ultrafine powder slurry obtained in Example 1 was adjusted to a solid content concentration of 45% by weight, blended with a material for an extruded cement board, and a specimen (1 cm × 4 cm × 16 cm) was prepared. ) Was measured. The mixing ratio was as shown in Example 3 shown in Table 1 below. As shown in Table 1, in Example 3, 25.0% by weight of an ultrafine powder slurry was added in terms of solid content. Comparative Examples 1 and 2
Was carried out for comparison, and similar specimens were prepared at the mixing ratios shown in Table 1. In Comparative Example 1, 10.0 wt% of ordinary scrap obtained by dry-pulverizing an extruded cement board was blended in place of the ultrafine powder slurry of Example 3. In Comparative Example 4,
Instead of the ultrafine powder slurry of Example 3, 25.0% by weight of the above-mentioned ordinary scrap was blended.

[0020]

[Table 1]

Each material is blended, and a kneaded product for extrusion molding is prepared using only the water content of the ultrafine powder slurry (water / powder ratio is about 0.1%).
3) A 10 mm × 40 mm plate was formed by a vacuum extruder. The extrusion pressure at this time was 2.5 to 2.7 MPa. This is cured at 60 ° C. for 6 hours for steam for 180 hours.
After completion of autoclave curing at 6 ° C. for 6 hours, a finished product was obtained.
Example 3, apparent density and bending strength of Comparative Examples 1 and 2,
Table 2 shows the results regarding the specific strength. In addition, the measuring method of apparent density and bending strength was as follows. Apparent density: Weight (wg) and volume (vcm ³ ) of test specimen:
Length x width x length). Flexural strength: Based on "10.5 measurement" and "10.6.2 Flexural strength" of JIS R 5201 "Physical test method of cement".

[0022]

[Table 2]

It is desired that the molded article be lightweight and have high strength. Therefore, it is preferable that the specific strength is large.
Comparative Example 1 corresponds to a mixture containing 10% by weight of ordinary scrap, and has almost the same specifications as a commercially available extruded cement board. The extruded cement board of Example 3 is comparable to such an extruded cement board. On the other hand, in Comparative Example 2 in which 25% by weight of normal scrap was blended, the bending strength and the specific strength were significantly reduced. From these results, it is understood that the ultrafine powder slurry obtained in the present invention does not deteriorate the product even if it is blended in a larger amount than usual scrap.

Example 4, Comparative Examples 3 and 4 The ultrafine powder slurry obtained in Example 1 was subjected to a solid concentration of 50.
It was adjusted to 0% by weight, blended in cement mortar, and measured for flexural strength and compressive strength of a test specimen (1 cm × 4 cm × 16 cm). The compounding ratio was as in Example 4 shown in Table 3 below. As shown in Table 3, in Example 4, 25.0% by weight of an ultrafine powder slurry was added in terms of solid content. A fluidizing agent (Mighty 150) was also blended at the blending ratio shown in Table 3.
Comparative Examples 3 and 4 were performed for comparison, and similar specimens were prepared at the blending ratios in Table 3. Comparative Example 3 contained no waste material and increased the amount of silicalite coarse powder. In Comparative Example 4, 25.0% by weight of ordinary scrap obtained by dry-pulverizing an extruded cement plate was blended in place of 25.0% by weight of the ultrafine powder slurry of Example 4.

[0025]

[Table 3]

Each material was blended, and water was added to the mixture so that the water / cement ratio (W / C) = 0.6. From molding to demolding was performed in 24 hours, a mortar specimen (W / C) was prepared. C =
0.6, W / P = 0.33). This is 60 ° C, 8
The product was cured through steam curing for 180 hours and autoclaved for 6 hours at 180 ° C. to obtain a finished product. Example 4, Comparative Examples 3 and 4
Table 4 shows the results regarding the apparent density, flexural strength, compressive strength, and specific strength. The methods for measuring the apparent density, bending strength and compressive strength were as follows. Apparent density: Weight (wg) and volume (vcm ³ ) of test specimen:
Length x width x length). Flexural strength: Based on "10.5 measurement" and "10.6.2 Flexural strength" of JIS R 5201 "Physical test method of cement". Compressive strength: Based on “10.5 measurement” and “10.6.1 Compressive strength” of JIS R 5201 “Physical test method of cement”.

[0027]

[Table 4]

As shown in the results of Table 4, the specimen of Example 4 is comparable to the specimen of Comparative Example 3 in which no waste material is blended. On the other hand, in Comparative Example 4 in which 25% by weight of normal scrap was blended, the bending strength and the specific strength were significantly reduced. From these results, it is understood that the ultrafine powder slurry obtained in the present invention does not deteriorate the product as compared with the normal scrap, even when blended in a large amount with other cement products.

[0029]

As is clear from the above description, according to the present invention, it is possible to pulverize waste cement molded products including fibrous materials by pulverization, and to obtain the obtained ultrafine powder as a raw material for cement molded products. The present invention provides a method for pulverizing and recycling a waste material of a cement molded article which can be reused as at least a part of the method.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of an embodiment of a crushing treatment method and a recycling method for waste cement molded products according to the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 Manufacturing process of cement molded article containing fibrous material 101 Primary crushing process 102 Addition process of aqueous medium 103 Addition process of dispersant 104 Wet crushing process

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C04B 18/16 ZAB (C04B 28/02 // (C04B 28/02 18:16 18:16 14:40 14:40 16 : 02) Z 16:02) 111: 20 111: 20 B09B 5/00 F (72) Inventor Tatsuya Tsuchida 3-8-1 Nishikanda, Chiyoda-ku, Tokyo Asanouchi Co., Ltd. (72) Inventor Yoshinori Yamada Aichi 2-1-1, Sakae, Naka-ku, Nagoya, Japan F-term in Asano Chubu Branch (Reference) 4D004 AA31 AC04 BA02 CA04 CB13 CC05 4D063 FF02 FF13 FF35 GA10 GD02 GD27 4D067 EE42 GA06 GA20 4G012 PA16 PA22 PA30 PC12

Claims (5)

[Claims] 1. A method for pulverizing waste cement molded product, which comprises wet-grinding the waste cement molded product containing a fibrous material in an aqueous medium to ultrafine powder. 2. A method for pulverizing waste cement molded products, which comprises wet-grinding the waste cement molded products containing fibrous materials in an aqueous medium in the presence of a dispersing agent and ultrafinely pulverizing the waste materials. 3. An aqueous medium is added to a waste cement molded product containing a fibrous material, and the resulting mixture of the waste cement molded product and the aqueous medium is wet-milled to ultrafine powder.
A method for recycling waste cement molded products, comprising using the obtained ultrafine powder as at least a part of raw materials in the production of cement molded products. 4. The recycling of waste cement molded products according to claim 3, wherein a dispersing agent is added after the aqueous medium is added to the waste cement molded products, and then wet grinding is performed. Method. 5. The method according to claim 1, wherein after the dispersant is added to the aqueous medium, the aqueous medium is added to the waste cement molded product, and the resulting mixture of the waste cement molded product and the aqueous medium is wet-pulverized. The method for recycling waste cement molded products according to claim 3, characterized in that: