JPH0920541A - Molding using fly ash as raw material and its production - Google Patents

Abstract

PURPOSE: To effectively reutilize fly ash discharged from a thermoelectric power plant, etc. CONSTITUTION: A stirring and mixing step P1 for adding a fiber B for reinforcement, a coloring matter (or pigment) C and a curing catalyst D to fly ash, stirring and mixing these raw materials and obtaining a substrate E is practiced. Then, a kneading step P2 for obtaining a molding material B by adding a curing agent comprising a prescribed amount of phenolic resin F to a substrate and kneading the these materials is practiced. At this time, the curing agent is added in an amount of 20-28cc based on 100g fly ash. Then, a pressure molding step P3 for carrying out pressure molding of the molding material G by a mold press machine and obtaining a molding H is practiced. Molding pressure at this time is 10-30t, preferably about 15t. Lastly, a heat-drying step P4 for heating and drying the molding H removed from the mold at 100-120 deg.C for 20-30min is practiced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fly ash (coal ash) discharged from a thermal power plant, for example, and a method for producing the same, which is made of fly ash as a raw material.

[0002]

2. Description of the Related Art For example, in a thermal power plant, fly ash (coal ash) is constantly discharged.
Such fly ash has been used in part by being mixed with cement at about 5% as a filler for cement, or mixed with clay at about 7% as a filler for clay for roof tiles. However, the amount of fly ash reused in this way is only 10% or less of the whole,
Most of the rest were treated as industrial waste, such as landfill.

[0003]

By the way, treating fly ash as industrial waste requires a great deal of cost, and in recent years, problems of shortage of waste treatment facilities, securing of resources, and environmental protection have become serious. I'm doing it. For this reason,
Even with the fly ash as described above, it is required to recycle it as an industrial material and effectively use it, instead of landfilling it.

The present invention has been made in view of such circumstances, and an object thereof is to form fly ash discharged from a thermal power plant or the like using fly ash as a raw material which can be effectively reused. To provide a product and a manufacturing method thereof.

[0005]

[Means for Solving the Problems] A molded article made from fly ash according to the present invention is bonded and cured by adding a curing agent and a curing catalyst made of a thermosetting resin to a base material mainly composed of fly ash. It is characterized by the fact that it is made possible (the invention of claim 1). In this case, 20 cc to 28 cc of the curing agent is added to 100 g of the fly ash.
It is desirable to add (invention of claim 2). Further, the curing agent may be a phenol resin (the invention of claim 3). Furthermore, it is more effective if the reinforcing fiber is contained in the base material (the invention of claim 4).

The method for producing a molded article using fly ash as a raw material of the present invention comprises a kneading step of kneading by adding a curing agent and a curing catalyst made of a thermosetting resin to a base material mainly composed of fly ash. The present invention is characterized in that a pressure molding step of pressure molding the kneaded molding material and a heat drying step of heating and drying the molded product are performed (the invention of claim 5). In this case, it is desirable that the molding pressure in the pressure molding step be 10t to 30t (the invention of claim 6).

[0007]

Operation Fly ash is a powder having a strong alkalinity, and it has been conventionally considered difficult to solidify such a powder having a strong alkalinity. The present inventor has conducted experiments and researches for the effective use of fly ash. As a result, by using a thermosetting resin as a curing agent, it is possible to mold and cure fly ash, which has been considered difficult in the past. Therefore, they have completed the present invention.

That is, a hardener composed of a thermosetting resin and a curing catalyst are added to a base material mainly composed of fly ash and kneaded, and the kneaded molding material is pressure-molded by using a molding die and molded. By heating and drying the product, it becomes possible to solidify the fly ash by using the curing agent as a binder.
It was possible to obtain a molded product with sufficient mechanical strength. At this time, fly ash can be molded and cured without requiring particularly difficult steps such as a firing step, special expensive chemicals, or a large amount of energy. The manufacturing is simple, can be performed in a relatively short time, and can be inexpensive.

In this case, an appropriate amount of the curing agent added is 20 cc or more and 28 cc or less with respect to 100 g of fly ash. Too little hardener added (fly ash 1
If it is less than 20 cc with respect to 00 g), curing will be insufficient and molding will not be possible, or sufficient strength will not be obtained even if molding is possible. On the other hand, too much hardener was added (28 cc for 100 g of fly ash).
If it is more than 1), the molded product adheres to the molding die and the mold cannot be released.

As the curing agent composed of this thermosetting resin, a phenol resin, an epoxy resin, a urea resin, or a melamine resin can be used. Among these, the one using the phenolic resin can obtain the highest strength of the molded product and can also minimize the water absorption of the molded product. Therefore, when it is desired to obtain a molded product that is required to have high strength and low water absorption, it is optimal to use a phenol resin as a curing agent.

As the above-mentioned curing catalyst, various ones such as "Euroid" can be adopted, and the addition of this curing catalyst can sufficiently cure the molding material, and shorten the time required for curing. can do. At this time, the addition amount of the curing catalyst is preferably 1 to 10 g with respect to 400 g of fly ash, and if the addition amount is too small, curing failure will occur. Also, even if the addition amount of the curing catalyst is too much, there is no problem in molding,
Since the curing time does not change so much, it leads to a high cost. Incidentally, it goes without saying that this curing catalyst can be added to the base material in the step of kneading, but if a curing agent to which the curing catalyst has been added in advance is used, the trouble of adding it later can be eliminated.

Then, in the above pressure molding step,
The molding pressure is preferably 10 t or more and 30 t or less, and most preferably about 15 t. If the molding pressure is less than 10t, the molding material will not be sufficiently hardened and molding will not be possible. Even if molding is possible, the molding material will not spread on average and the structure will be dense and dense, resulting in partial strength. May become weaker, or blister may occur during heating and drying. On the other hand, if the molding pressure is too high, it may be difficult to dry, and the density may become uneven, causing cracks and cracks.

Further, in the heating and drying process, 10
It is desirable to heat-dry at a temperature of 0 ° C to 120 ° C for an appropriate time, and if the drying temperature is too high, the moisture remaining in the molded product is rapidly warmed and evaporated, causing cracks or cracks or the molded product. May be warped and deformed. The drying temperature may be somewhat low, but it takes a long time to dry. Further, it is desirable that this heating and drying step is carried out in a state where the molded product is placed in a constant temperature dryer and is shielded from the outside air, so that it is possible to prevent product variations from occurring. By adding a heating function to the mold used in the pressure molding step, the molded product can be heated and dried in the mold, and the pressure molding step and the heat drying step are executed almost simultaneously. It is also possible.

By the way, molded articles made of the fly ash obtained by the above-mentioned manufacturing method are, for example, flower pots, planters, sound pots, earth retaining blocks for flower beds, garden stones, stepping stones, gardening articles such as lanterns, and road tiles. It can be used in various products such as earth building such as piles, piles and blocks, wall materials, floor materials, ceiling materials, building materials such as decorative tiles and roof tiles, art ornaments such as statues, etc. It can be provided as an alternative to products and stone products.

At this time, the strength of the molded product can be improved by mixing the reinforcing fiber into the base material mainly composed of fly ash. As this reinforcing fiber,
For example, a short synthetic fiber (so-called semi-hair) cut into a length of several mm, glass fiber, ceramic fiber or the like can be used. Further, as the mixing amount of this reinforcing fiber,
1 to 5 g is suitable for 400 g of fly ash. If the amount of the reinforcing fibers mixed is too large, the adhesion area between the fly ash and the curing agent will decrease, and there is a risk that the strength will decrease. Further, when the reinforcing fibers are mixed, it is desirable to mix the reinforcing fibers with the base material in advance and sufficiently stir the mixture before the kneading step in which the curing agent is added and kneaded. If it is sufficient and the reinforcing fiber remains partially clogged, it may cause cracking or decrease in strength.

If desired, the base material may be mixed with other mixed materials such as so-called wood wool and shirasu. When the color of fly ash itself appears in the molded product, it becomes a gray product, so it is possible to premix the colorant (pigment) with the base material. It can produce color and enhance the value of the product. Furthermore, by mixing a foaming agent into the base material,
It is also possible to obtain a lighter shaped article having innumerable bubbles similar to aerated concrete (ALC).

Since the strength of the molded article also changes depending on the type of the above-mentioned curing agent, the type of the curing agent can be changed according to the product. Of these, by using the phenolic resin as described above, it is possible to obtain a molded product having the lowest water absorption and the highest strength. Further, the one using the phenolic resin had the smoothest appearance as compared with the case using the other ones.

The inventor of the present invention has found that the molded article formed by using a phenolic resin in a tile shape has physical properties (strength, water absorption, cold resistance) comparable to those of general clay roof tiles as roof tiles. ) Was obtained. Such a roof tile made of fly ash as a raw material can be provided at a low cost because the raw material itself can be obtained at a low cost and the manufacturing process is simple without the need of firing. Moreover, while the weight of the fired roof tiles is 2.8 kg on average,
The weight is as light as 2.0 kg.

On the other hand, an epoxy resin is easier to mold than other resins because it has less cracks when dried, but is relatively expensive, so it is suitable for high value-added products such as art ornaments. Conceivable. Further, the urea-based resin and the melamine-based resin have the merit that they can be obtained at low cost, but they have lower strength than the above-mentioned two and are not suitable for molded articles having complicated shapes, so it is desirable to mold them into a flat plate shape. Suitable for building wall materials and ceiling materials. Further, since it has high water absorbency, it is also suitable for flower pots and the like.

Therefore, according to the present invention, it is possible to inexpensively obtain a molded product that can replace the existing concrete product or ceramic product by using fly ash as a raw material and through a relatively simple manufacturing process. Effectively reuses fly ash, an industrial waste, as a resource (recycling)
Is what you can do.

[0021]

Embodiments of the present invention will be described below with reference to FIG. FIG. 1 shows a manufacturing process of a molded product made of fly ash as a raw material according to this embodiment. First,
Fly ash A, which is a raw material, is discharged from, for example, a thermal power plant, and has a component composition shown in Table 1 below. If the fly ash A contains moisture, the quality of the product will vary. Therefore, if the fly ash A contains moisture, it should be dried sufficiently before use.

[0022]

[Table 1]

To the fly ash A, the reinforcing fiber B, the dye (pigment) C, and the curing catalyst D are added, and the stirring and mixing step P1 is executed. Of these, the reinforcing fiber B is
For example, short synthetic fibers (so-called semi-hairs), glass fibers, ceramic fibers, etc., cut into a length of several mm can be used, and the mixing amount of this reinforcing fiber B is 1 to 400 g of fly ash A. ~ 5g.

Further, the pigment C is added to give a desired coloring to the product, and when manufacturing roof tiles, for example, azuki pigment is used. The mixing amount of this dye C is 40
It is set to 10 to 30 g for 0 g of fly ash A. As the curing catalyst D, for example, euroid powder curing agent is used, and 1 to 10 g, preferably 4 to 6 g is added to 400 g of fly ash A.

In the stirring and mixing step P1, the fly ash A, the reinforcing fiber B, the dye (pigment) C, and the curing catalyst D are accurately weighed, respectively, and then charged into, for example, a general-purpose stirrer, and 20 to 30. It is performed by stirring for a minute. As a result, the base material E that is sufficiently stirred and mixed is obtained. At this time, it is important that the reinforcing fibers B are completely separated and mixed, and if the agitation is insufficient, it may cause cracks and a decrease in strength of the molded product, which will be described later.

Next, a predetermined amount of a thermosetting resin, in this case a phenolic resin F, is added to the base material E,
A kneading step P2 of kneading is performed. As the phenol resin F, for example, a liquid resin obtained by synthesizing a phenol resin and formalin in a ratio of about 1: 1 is used, and 80 to 110 for 400 g of fly ash A.
cc is added. As will be described later, if the amount of the curing agent added is too small, curing will be insufficient and molding will not be possible, or sufficient strength will not be obtained even if molding is possible. On the other hand, if the amount of the curing agent added is too large, the molded product will adhere to the molding die, making it impossible to release it.

This kneading step P2 is carried out for 3 to 10 minutes using, for example, a screw type general-purpose kneader. The kneading is performed evenly, and when the material has a hardness of about an earlobe, the kneading step P2 is completed, and the molding material G is obtained.
As will be described later, as the above-mentioned curing agent,
Other than the phenolic resin F, an epoxy resin, a urea resin, and a melamine resin can be used. Also,
The curing catalyst D may be added in this step.

Subsequently, a pressure molding step P3 for pressure molding the molding material G is executed. This pressure molding step P3
Is performed using a die press machine, and depending on the shape of the die,
For example, molded articles H having various shapes and uses such as roof tiles and wall panels can be obtained. As described later, the molding pressure in this pressure molding step is preferably 10 to 30 t, and most preferably about 15 t. If the molding pressure is too low, the molding material will not be sufficiently cured and molding will be impossible. If the molding pressure is too high, the density of the molded product will be uneven and cracks or cracks may occur.

Finally, a heating and drying step P4 for heating and drying the molded product H released from the die pressing machine is executed. The heating and drying step P4 is performed using, for example, a tunnel-type constant temperature dryer, the molded product H is dried at a temperature of 100 to 120 ° C. for 20 to 30 minutes, and the molded product H is completely dried to obtain the product I. Is obtained. If the drying temperature is too high, the water remaining in the molded product H is rapidly warmed and evaporated, which may cause cracking or cracking of the molded product H or warp deformation. The drying temperature may be somewhat low, but it takes a long time to dry. Although not shown, after the pressurizing step P3 and after the heating and drying step P4, an inspection step is executed so that the appearance and physical properties of the molded product H and the product I can be checked. Has become.

By the steps described above, it has become possible to mold and harden fly ash A, which is a powder having a strong alkalinity and which has been considered difficult in the past. The product I obtained by the above-mentioned manufacturing method has sufficient strength, for example, garden pots such as flower pots, planters, sound pots, earth retaining blocks for flower beds, garden stones, stepping stones, and lanterns,
It can be used as various products I for road construction tiles, piles, blocks, etc. for earth construction, wall materials, flooring materials, ceiling materials, building tiles, roof tiles, etc., art ornaments such as statues, etc. It can be provided as an alternative to the concrete products, ceramic products, stone products, etc.

Next, the appropriateness of the above-mentioned manufacturing process and the formulation of the molding material G will be illustrated based on some samples. In addition, all the samples described below are made of 400 g of fly ash as a main raw material, and have a length and width of 15 cm x 15 cm and a thickness of 1
It is molded into a flat plate of cm.

(1) Relationship between amount of curing agent and moldability As shown in Table 2 below, Samples 1 to 6 are 400 g of fly ash, 5 g of curing catalyst, 1 g of reinforcing fiber (half-hair). Is a molded product formed by changing the amount of a curing agent made of a phenolic resin added in 10 cc increments on a substrate made of 20 g of a dye (pigment). The molding pressure is fixed at 15 t, and the drying condition is fixed at 120 ° C. for 30 minutes.

The following Table 2 shows the test results of the samples 1 to 6 which were examined for moldability, that is, mold releasability and curability. In the column of evaluation in the table, "excellently good" is shown, "good" is shown as "good", "normal" is shown as "triangle", "not good" is shown as "x", and unevaluable is shown as "-".

[0034]

[Table 2]

As is clear from Table 2, 8 g of the curing agent (phenolic resin) was added to 400 g of fly ash.
By adding 0 to 110 cc (Samples 2 to 5), molding becomes possible, especially 90 cc (Sample 3)
Gave the best results. On the other hand, in the case of the sample 1 containing 70 cc of the curing agent, the curing was insufficient, and the sample was easily disintegrated by holding it by hand. Further, in Sample 6 in which the curing agent was 120 cc, the molded product adhered to the mold in the pressure molding process, and the mold release was impossible. Although not shown in the table, almost the same results were obtained with curing agents other than the phenolic resin.

Therefore, the amount of the curing agent is 4
80 to 110 cc is suitable for 00 g, and if converted, 20 to 28 cc for 100 g of fly ash.
Was found to be appropriate.

(2) Relationship between amount of curing catalyst and moldability Table 3 below shows samples 7 to 12 in which only the amount of the curing catalyst (euroid powder curing agent) was changed under the same other conditions. The test results of the releasability and curability are shown. Further, in the table, the above sample 3 (the amount of the catalyst is 5 g)
Is posted again.

[0038]

[Table 3]

As is clear from Table 3, in the sample 7 to which the curing catalyst was not added, the molded product did not cure at all, and molding was impossible. And 400g fly ash
Molding was possible by adding 1 g or more of the curing catalyst, but in Samples 8 and 9 in which the amount of the curing catalyst added was relatively small at 1 g and 3 g, the time required for the molded product to cure It took a little longer. On the other hand, even if the addition amount of the curing catalyst was increased (Samples 11 and 12), there was no problem in molding, but the time required for curing was almost the same as in Samples 3 and 10.

(3) Relationship between molding pressure and moldability In Table 4 below, the other conditions are the same and only the molding pressure is 5 t.
The test result which investigated the mold releasability and hardenability, and also the external appearance and the water absorption rate about the samples 13-18 which were changed by every step and molded was shown. In addition, in the table, sample 3 described above is used.
(Molding pressure is 15t) is listed again. In this case, the water absorption test was conducted in accordance with the water absorption test of JIS A5208, and the water absorption rate is shown in% in the table.

[0041]

[Table 4]

As is clear from Table 4, in Sample 13 having a molding pressure of 5 t, the molding material was not sufficiently cured and molding was impossible. On the other hand, when the molding pressure was 10 t or more (Samples 14 to 18, Sample 3), molding was possible, but the molding pressure was particularly high (Sample 17, Sample 18)
In, the appearance of cracks and bumps was seen. Sample 3 with a molding pressure of 15 t showed the best results for all. In addition, sample 14 with molding pressure of 10 t
Then, the result that the water absorption rate was slightly higher than that of the sample of 15t to 25t (Sample 3, Sample 15, Sample 16) was obtained.

(4) Relationship between Reinforcement Fiber Mixing Amount and Physical Properties of Products In Table 5, other conditions are the same, and the mixing amount of the reinforcing fiber (half hair) is changed in steps of 1 g. 25 shows the test results of the physical properties (water absorption, bending strength) of No. 25. In addition, the above-mentioned sample 3 (the amount of the reinforcing fiber is 1 g) is again shown in the table. In this case, the bending strength test is also performed based on the bending test of JIS A5208.

[0044]

[Table 5]

As is clear from Table 5, in Samples 3 and 20 to 23 in which 1 to 5 g of reinforcing fibers were mixed, the water absorption was relatively low and excellent strength could be obtained. On the other hand, in the sample 19 in which the reinforcing fiber was not added,
The bending strength was slightly inferior. And 6g of reinforcing fiber
In Samples 24 and 25 to which 7 g was added, the strength was extremely low (50 kgf or less in numerical value), and the product was broken (smashed into pieces) just by hitting. It is presumed that this is because the adhesive area between the fly ash and the curing agent decreases due to the excessive amount of the reinforcing fibers.

(5) Relationship between Type of Curing Agent and Physical Properties of Product Finally, Table 6 shows physical properties (water absorption rate) of Samples 26 to 31 formed by changing types of curing agents (thermosetting resins). And the bending strength) are shown. Also,
In the table, Sample 14 and Sample 3 using the above-mentioned phenolic resin are listed again. In addition, here, those samples 1
4 and sample 3 only frost damage test (JIS A520
8) and the results are also shown. Furthermore, examples of conformity of molded products using each curing agent as products are also shown.

[0047]

[Table 6]

As is clear from Table 6, the samples 14 and 3 using the phenolic resin had the lowest water absorption and the highest bending strength. Furthermore, good results were obtained in the freeze damage test. Although not shown in the table, among the four types of curing agents,
Sample 14 and sample 3 using the phenolic resin had the best releasability, and the surface condition of the molded product was the smoothest. Therefore, a molded product using a phenolic resin as a curing agent is suitable for various building materials, and is also suitable for use as a roof tile that has low water absorption and requires high strength.

On the other hand, the samples 26 and 27 using epoxy resin as the curing agent have a slightly higher water absorption rate and a little inferior bending strength as compared with the above-mentioned samples 14 and 3, but the conditions are strictly controlled. Even without it, it was easy to cure and had few cracks. Therefore, the molded product using the epoxy resin as the curing agent is suitable not only for various building materials such as wall materials and tiles, but also for high value-added products such as art ornaments such as duplicate statues.

Samples 28 to 31 using urea resin or melamine resin as the curing agent are slightly inferior in bending strength to the above two samples. The samples 28 and 29 had relatively high water absorption. However, these urea-based resins and melamine-based resins are advantageous in that they are inexpensive and are suitable for building materials such as wall materials and ceiling materials, and also suitable for flower pots, earth retaining blocks for flower beds, and the like.

Although not shown in the table, the present inventor also conducted a test in which the heating and drying process was performed on some samples while changing the drying temperature. As a result, it became clear that in the heat drying step, it is desirable to heat dry at a temperature of 100 ° C. to 120 ° C. for an appropriate time (20 to 30 minutes). If the drying temperature is too high, the moisture remaining in the molded product is rapidly warmed and evaporated, which may cause cracking or cracking of the molded product or warp and deformation of the molded product. Also,
The drying temperature may be somewhat lower, but it will take longer to dry.

As described above, according to the present embodiment, by using the thermosetting resin as the curing agent (binder), it is possible to bond and cure the fly ash having strong alkalinity, which has been considered difficult in the past. We were able to. It was confirmed that the molded product can be used as various products. Therefore, it is possible to effectively reuse (recycle) fly ash, which has conventionally been used only as a filler for cement and the like, as an industrial resource.

In addition, fly ash is used as a raw material by a method such as a kneading step, a pressure molding step, a heat drying step, which is technically simple and does not require a particularly complicated device and consumes a large amount of energy. The molded product can be obtained easily and inexpensively. As a result, it is possible to greatly contribute to solving the problem of securing resources and the problem of environmental protection as well as the advantage in cost.

The present invention is not limited to the above-mentioned embodiments, and the following expansions and modifications are possible. That is, by mixing a foaming agent in the base material, a lighter molded product having innumerable bubbles similar to aerated concrete (ALC) can be obtained. Further, a curing agent to which a curing catalyst has been added in advance in the thermosetting resin may be used, and the trouble of adding the curing catalyst later can be eliminated. Furthermore, by adding a heating function to the mold press used in the pressure molding process, the molded product can be heated and dried in the mold, and the pressure molding process and the heat drying process can be performed almost simultaneously. It is also possible to execute.

[0055]

As is apparent from the above description, according to the present invention, by using a thermosetting resin as a binder, it is possible to bond fly ash having strong alkalinity, which has been considered difficult in the past, In addition to being able to be cured, the molded product can be obtained easily and inexpensively, and the molded product can be used as various products. As a result, fly ash can be effectively reused (recycled) as an industrial resource.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention and showing a manufacturing process.

[Explanation of symbols]

In the drawing, A is fly ash, B is reinforcing fiber, D is a curing catalyst, E is a base material, F is a phenolic resin (curing agent),
G indicates a molding material, and H indicates a molded product.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C08L 61/06 LMS C08L 61/06 LMS // (C04B 26/12 18:08 14:38 14:42 16: 06) B29K 61:04 105: 26 C04B 111: 00

Claims (6)

[Claims] 1. A molded article made of fly ash as a raw material, which is obtained by adding a curing agent and a curing catalyst made of a thermosetting resin to a base material mainly composed of fly ash and binding and curing the same. 2. The fly ash 10 is used as the curing agent.
20cc-28cc is added with respect to 0g, The molded article which used the fly ash of Claim 1 as a raw material. 3. A molded article made of fly ash as a raw material according to claim 1, wherein the curing agent is a phenolic resin. 4. The molded article made of fly ash as a raw material according to claim 1, wherein the base material contains reinforcing fibers. 5. A kneading step of adding a curing agent and a curing catalyst made of a thermosetting resin to a base material mainly composed of fly ash and kneading, and a pressure molding step of pressure-molding the kneaded molding material. A method for producing a molded article using fly ash as a raw material, which comprises performing a heating and drying step of heating and drying the molded article. 6. The molding pressure in the pressure molding step is,
It is 10t-30t, The manufacturing method of the molded article which uses the fly ash as a raw material of Claim 5 characterized by the above-mentioned.