JPH06166579A - Production of lightweight cellular building material produced by using coal ash as main raw material - Google Patents

Abstract

PURPOSE:To produce a lightweight cellular building material having excellent properties unattainable by conventional material by using coal ash as a main raw material together with inexpensive materials as other additives. CONSTITUTION:A porous sintered material is produced by mixing coal ash with at least one kind of binder selected from blast furnace slag and incineration ash of sewage sludge in combination with a forming assistant, forming the mixture and baking the formed product to melt the binder and expand the air in the coal ash. The binder is melted by baking to form the bonding part of the coal ash particles and, thereafter, the air in the coal ash is expanded to form the objective lightweight cellular building material having a low bulk density and closed cell structure. The surface of the lightweight cellular building material has low water-absorption owing to the presence of the molten binder. A lightweight cellular building material having low water-absorption and low bulk density and useful as a building material can be produced at a low cost while effectively utilizing industrial wastes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a light-weight foam building material using coal ash as a main raw material. It relates to a method for inexpensively producing a useful lightweight foam building material having characteristics.

[0002]

2. Description of the Related Art A large amount of coal ash is discharged from a coal-fired power plant, and the amount of the discharge tends to increase year by year. Therefore, studies have been made on how to effectively use the coal ash.

Conventionally proposed effective utilization methods of coal ash include concrete admixtures for cement or road and building materials. Among these, as a usage method for building materials, a method of mixing coal ash with cement and curing it, or adding an aggregate and a binder (cement etc.) and firing,
There is a method of obtaining a porous body having a water absorption of several% (more than a stoneware) by baking.

[0004]

In the conventional utilization method, there is no utilization method in which a large amount of coal ash is used and coal ash is used as a main raw material, and a large amount of other additives are required. The cost cannot be reduced significantly. The obtained product is a product with low added value such as brick. There was a drawback.

The present invention solves the above-mentioned conventional problems and uses a coal ash as a main raw material, and also uses an inexpensive additive as another additive to provide a lightweight foam building material having unprecedented excellent properties. It is intended to provide a method for manufacturing.

[0006]

[MEANS FOR SOLVING THE PROBLEMS] The method for producing a lightweight foam building material using coal ash as a main raw material of the present invention is selected from the group consisting of coal ash, waste of ceramic glaze, blast furnace slag and sewage treatment sludge incineration ash. At least one binder and a molding aid are mixed and molded, and then fired to melt the binder and expand the air in the coal ash to obtain a porcelain lightweight sintered body. It is characterized by

The present invention will be described in detail below.

In the present invention, first, coal ash, a binder and a molding aid are mixed at a predetermined ratio with water, if necessary, to prepare a molding raw material.

In the present invention, as the binder, the waste of the ceramic glaze, that is, the mixed powder of the ceramic and the glaze produced as a by-product during the production of the ceramic, the blast furnace slag discharged from the ironworks or the sewage treatment sludge is used. Use incineration ash obtained by incineration. These binders may be used alone or in combination of two or more.

The molding aid is used for holding the shape at the time of molding, and the molding aid is clay and / or an organic binder such as polyvinyl alcohol (PVA),
Methyl cellulose (MC) or the like can be used. Regarding the molding aid, one kind may be used alone, or two or more kinds may be mixed and used.

The mixing ratio of these raw materials is preferably coal ash: 50 to 90% by weight, binder: 10 to 40% by weight, molding aid: 0 to 20% by weight.

That is, when the proportion of coal ash is high, the material becomes lighter, and when the proportion is low, the material becomes heavier. Higher proportions of binder foam at lower temperatures, lower proportions do not foam up to high temperatures. Further, if the proportion of the molding aid is small, the moldability is insufficient, and if it is large, various molding methods can be adopted.

A more preferred blending ratio is coal ash: 60 to 80% by weight, binder: 10 to 30% by weight, molding aid: 5 to 20% by weight.

The method of mixing these raw materials is not particularly limited, and the binder and the molding aid may be mixed in advance and then coal ash may be added and mixed. Alternatively, all raw materials may be added and mixed at the same time. May be.

The molding raw material thus obtained is molded by a molding method such as uniaxial pressure press or extrusion molding and then fired.

The firing temperature is a temperature at which the raw materials can be foamed, and it depends on the raw material composition, but in general, 1100 to 12
The range is 50 ° C.

The firing melts the binder, and then the air in the coal ash expands and foams, resulting in a low specific gravity,
A low bulk density porous sintered body is produced.

[0018]

The binder used in the present invention is solid (silicate-based) industrial waste having a lower melting point than coal ash. Although this binder is provided at a low cost, due to its low melting point, it melts prior to coal ash to form a dense coal ash particle bonded portion upon firing.

On the other hand, coal ash contains residual air inside,
Although its specific gravity is small per se, after melting the binder during firing, the air inside the coal ash expands and foams, forming good closed pores between the bonded parts of the binder.

As a result, a lightweight foam building material having a high porosity and a low bulk density can be obtained. Moreover, since the pores of this lightweight foam building material are closed pores, and the dense portion derived from the fused portion of the binder is formed on the surface, the water absorption is low and the characteristics as a building material are excellent.

In such a method of the present invention, it is a very important requirement that the binder melts to bond the coal ash particles to each other before the coal ash expands and melts. A good lightweight foam building material can be obtained by imparting a foaming action to.

In the conventional method, in order to produce a lightweight foam building material, an expensive additive such as SiC for causing a foaming action is required, which causes a rise in raw material cost. In addition, it becomes possible to manufacture coal ash, which is an industrial waste, and a binder at low cost by using a molding aid.

[0023]

EXAMPLES The present invention will be described in more detail with reference to examples.

Example 1 A molding raw material was prepared with the composition shown in Table 1, molded by a uniaxial pressing method, and then fired at a temperature shown in Table 1 to obtain a lightweight foam building material.

The reduced pressure water absorption and the bulk density of the obtained lightweight foam building material were measured, and the results are shown in Table 1. The water absorption under reduced pressure was measured according to the EN method, and the bulk density was measured by the Archimedes method.

From Table 1, it is clear that according to the present invention, a lightweight foam building material having a low bulk density and a low water absorption rate can be produced by using an inexpensive raw material.

[0027]

[Table 1]

Example 2 A lightweight foam building material was produced in the same manner as in Example 1 except that the raw material composition and firing temperature shown in Table 2 were used, and the characteristics and physical properties of each lightweight foam building material were examined by the following test methods. The results are shown in Table 2.

Test method (average of 5 samples) Water absorption under reduced pressure: Complies with EN method Boiling water absorption: Water absorption after boiling for 3 hours and standing for 24 hours Water absorption after 24 hours: According to JIS A 5209 Bulk density: Archimedes method

[0030]

[Table 2]

[0031]

[Table 3]

From Tables 2 and 3, it is clear that, according to the present invention, a lightweight foam building material having a low bulk density and a low water absorption rate can be produced by using an inexpensive raw material.

[0033]

As described in detail above, according to the method for producing a lightweight foam building material using coal ash as a main raw material of the present invention, an inexpensive raw material is used, which has a low water absorption rate, a small bulk density, and is used as a building material. An extremely useful lightweight foam building material can be easily and efficiently manufactured at low cost.

The method of the present invention effectively manufactures industrial waste discharged in various fields as a main raw material to produce a high value-added product, and also from the viewpoint of greatly reducing the amount of waste. This is an industrially extremely advantageous method.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mamoru Toriyao 1-20-20 Kitakaseyama, Odaka-cho, Midori-ku, Nagoya-shi, Aichi Chubu Electric Power Co., Inc. Electric Power Technology Research Institute (72) Inventor Yukito Muraguchi Koiemoto-cho, Tokoname-shi, Aichi 5-chome Inax Co., Ltd. (72) Inventor Yamazaki Gogo 5-1-1 Koi Ehoncho, Tokoname-shi, Aichi Prefecture Inax Co., Ltd. (72) Inventor Hajime Ota 5-chome, Koi-Ehoncho, Tokoname-shi, Aichi Stock Company Inside Inax (72) Inventor Yasuo Goto 5-1-1 Koiemotocho, Tokoname City, Aichi Prefecture Inside Inax Co., Ltd.

Claims (1)

[Claims] 1. Coal ash, at least one binder selected from the group consisting of ceramic glaze waste, blast furnace slag and sewage treatment sludge incineration ash, and a molding aid are mixed, and then molded. And a method for producing a lightweight foam building material using coal ash as a main raw material, characterized in that a porous sintered body is obtained by melting the binder and expanding the air in the coal ash.