JPH0741343A - Artificial lightweight aggregate composed mainly of coal ash - Google Patents

Abstract

PURPOSE:To obtain a lightweight aggregate to use for structural concrete by using coal ash discharged from thermoelectric power plant and fine particles discharged by grinding or drilling at the time of processing a glass plate, adding a foaming agent thereinto and granulating and burning. CONSTITUTION:The artificial lightweight aggregate is obtained by blending silicon carbide, the foaming material such as a amorphous carbonaceous material and a caking clay with the fine powdery coal ash and the glass fine particles, granulating and burning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION An object of the present invention is to mix a foaming material and a binder with coal ash and glass fine powder, obtain a lightweight aggregate by firing and use it for concrete. It is a lightweight and highly rigid new artificial lightweight aggregate suitable for use in concrete for construction of living space structures such as high-rise buildings, floating floating islands, floating floating buildings, etc. .

[0002]

2. Description of the Related Art Among lightweight aggregates, those that refer to granulated artificial lightweight aggregates that are the subject of artificial production. Among them, for the production of lightweight aggregates using coal ash as a main raw material, (1) Sho 36-12580. A method in which a mixture of pulp waste liquid and feldspar is added to fly ash, dried, and then fired at a temperature of 1200 ° C or higher. (2) Sho 41-3239, fly ash mixed with coal mine waste (bottom and scrap) and pulp waste liquid, and after molding and drying 1
A method of firing at 500 ° C. (3) Non-expansion property obtained by granulating spherical particles by continuous dropping of clay slurry and pulp waste liquid into fly ash continuously fed into a granulator and sintering at 1100 to 1500 ° C. Manufacturing method of lightweight aggregate. It is described that the fly ash was granulated and burned using lignin of the pulp waste liquid. Other methods for producing aggregates include (4) Sho 40-16270, coal ash and seawater magnesia,
A manufacturing method by blending magnesia-containing substances such as magnesite and dolomite is described. However, the artificial lightweight aggregates obtained by any of the methods are not yet satisfactory and are not on the market.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The present invention has been studied with the object of obtaining a lightweight aggregate having a higher aggregate strength than the lightweight aggregate obtained by the method for producing an artificial lightweight aggregate described in the prior art. Advanced. That is, when coal ash is heated alone 1
If the temperature is not higher than 200 ° C, it is not a substance that dissociates gas, which was one obstacle to the development of various products. It has been discovered that the present invention can obtain a hard and lightweight aggregate by low-firing firing because a low melting temperature can be obtained because it also acts as a medium by mixing fine glass powder. If low-firing firing is possible, it will have a favorable effect on production cost control, such as long-term operation of equipment and reduction of fuel costs.

[0004]

[Means for Solving the Problems] An artificial lightweight aggregate obtained by blending fine coal ash and fine glass powder with several kinds of foaming material and a binder and granulating the mixture, followed by firing.

[0005]

With the above-mentioned constitution, the reason why the glass fine powder is mixed with the coal ash lies in the components and properties of the plate glass. The fine glass powder has a viscosity near 600 ° C., and widely and continuously changes as the temperature rises. When cooled to a certain temperature, it solidifies to have hardness, and C.I. S. O
It also has elements that are easily gasified, and in the case of fine powder, foaming during melting from 850 ° C is remarkable. Melting progresses with coal-ash and other caking clays due to high-temperature chemical reaction caused by the interaction between elements due to burning, and the firing and hardening of aggregates are formed. Plate glass, which is a material of glass fine powder, is manufactured by carefully controlling and purifying high-purity raw materials individually, and mixing and controlling the amount, and it is of a high quality as a material to be added when manufacturing the lightweight aggregate of the present invention. It can be a stable raw material. Therefore, the granulated aggregate obtained by the combination with the coal ash can be of a reliable, lightweight and hard quality.

[0006]

[Examples] Two types of coal ash, fly ash and bottom ash, which were discharged from the Sakata City thermal power plant in Yamagata Prefecture, were used. Fly ash is a dried product with a uniform particle size, and the average particle size is 20 to 30 μm. The bottom ash belongs to sandy loam and has an average particle size of 0.4 to 0.5 mm. There are two experimental examples and the following is performed. In the first example, 90% by weight of fly ash and 10 parts by weight of bottom ash are mixed in (A), and in the second example, 80% by weight of fly ash and 20% by weight of bottom ash are mixed in (B). )
The blending ratio was 100 parts by weight. The fine glass powder was used after being dehydrated and dried, which was deposited by containing water generated by polishing and perforation during the processing of plate glass. Particle size is 2
It is thinner than 00 mesh. The amount used is 30 to 33 parts by weight for each of the blends of coal ash (A) and (B). Caking clay is bentonite and elutriated clay 2
The type used. The elutriated clay was the elutriated residue for the purpose of collecting quartz, but it was used together with bentonite as a binder because of its strong adhesive strength. The amount of binder used is coal ash (A), (B)
20 parts by weight were mixed in half with respect to the total parts by weight of the fine glass powders. Silicon carbide and an amorphous carbon material were blended for the purpose of expanding agent. The amount of silicon carbide used is 3.5 to 3.6 parts by weight based on the total parts by weight. The amorphous carbon material has a strong character as an aid for increasing the amount of silicon carbide due to the effect of the expanding agent, and G activated carbon was used. G activated carbon is a carbide produced from a waste tire by a special combustion method.
The amount used is 10 parts by weight based on the total weight,
Pre-stirred with silicon carbide. The reason is that the silicon carbide, which is added in a small amount, is uniformly dispersed. If there is unevenness, a uniform product cannot be obtained. These various materials were weighed and thoroughly mixed, and tap water was added to adjust the humidity. Granules having a particle size of 5 to 20 mm were granulated and dried to prepare the product. A shelf primer for preventing the welding of aggregates was melted in water in a fireproof container, applied to the inner surface of the container with a brush, and dried to prepare for firing aggregate. Aggregates were arbitrarily placed in the prepared container with a gap left between them and placed in an electric kiln. The set temperature was set to 1175 ° C. and electricity was applied to raise the sound. After reaching the predetermined temperature, the aiming was carried out for 15 minutes, the energization was stopped, and the natural cooling was waited. After cooling, the fireproof container was taken out from the electric kiln to obtain a lightweight aggregate as a fired body. Table 1 shows the properties of the lightweight aggregate obtained by the above examples.

[0007]

[Table 1]

[0008]

EFFECT OF THE INVENTION The lightweight aggregate obtained by the above experimental example was able to obtain the hardness superior to the conventional lightweight aggregate in strength by mixing and firing with fine glass powder. As is clear from the figures in the previous table, the water absorption rate is significantly lower than that of naturally occurring pumice aggregate, and the strength of the aggregate is great, so that the strength of lightweight concrete for building construction is significantly improved and there is no deterioration over time.

Claims (1)

[Claims] 1. Coal ash or glass fine powder to which one or more of silicon carbide as a swelling agent and an amorphous carbon material is added, and the mixture is granulated using a caking clay, and this is fired at a low degree of fire. An artificial lightweight aggregate.