JPS63274650A - Method for calcining fly ash or the like - Google Patents

Abstract

PURPOSE:To solidify fly ashes, etc., in a short period of time and to obtain a calcined body having excellent strength by molding a mixture composed of the fly ashes, etc., and calcined gypsum and/or cement, a mixture composed of water soluble Al salts and limes, and water, then calcining the same. CONSTITUTION:(A) <=94wt.% >=1 kinds among the fly ashes, volcanic ashes, loamy soil, blast furnace slag, municipal incineration ashes, and sludge (incineration ash), (B) >=5wt.% calcined gypsum and/or cement, (C) >=1wt.% mixture composed of a water soluble Al salt [e.g.: Al2(SO4)3] and limes at about 5:5 mixing ratio by weight, and (D) 60-70pts.wt. water per 100pts.wt. component B are mixed to obtain the mixture. The mixture is cast into a molding form and is solidified and dried for 10-30min; thereafter, the molding is calcined for >=30min at 800-1,300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of firing fly ash, etc., and particularly to a method of firing using calcined gypsum or cement.

[Prior art and its problems]

BACKGROUND ART Conventionally, the walls of each room in prefabricated houses and the like are made of board material or two wall materials made by pasting various cloths and paper on board materials, leaving a hollow space between the core materials. In addition, foamed polymer resin has been injected into the cavity for soundproofing and moisture proofing purposes, but this foamed polymer resin has the drawbacks of being expensive and flammable. Furthermore, ACL is used as a material other than plate materials.
Boards, cement wood wool boards, 90,000 gypsum boards, etc. are used, but they are expensive and heavy, making them inconvenient to handle and difficult to install on shelves or walls.

On the other hand, fly ash (coal incineration ash: including clinker ansh, sindar, and sh) produced at thermal power plants is
It is used in small quantities by mixing it with cement, or it is disposed of in landfills as the same treatment as other types of waste. At present, incineration ash from municipal garbage and other waste has no use at all other than being disposed of in landfills as the same treatment as other types of waste.

Furthermore, sludge from urban water purification facilities, sewage purification facilities, rivers, ports, etc. is either disposed of as is, or it is incinerated to remove organic matter and then the incinerated ash is disposed of. And there is no way to use it.

Furthermore, not only is volcanic ash soil completely abandoned, but volcanic ash, which interferes with daily life and road construction, is disposed of at great expense, and there is international interest in the effective use of this volcanic ash. ing.

Furthermore, like fly ash, blast furnace slag is mixed into cement and used as blast furnace slag cement, but the surplus is only used for roadbed materials as a substitute for crushed stone.

[Means to solve the problem]

This invention has been proposed in view of the above-mentioned conventional circumstances, and provides low-cost use of fly ash, blast furnace slag, volcanic ash, loamy soil, sludge, and sludge incineration ash (hereinafter referred to as fly ash, etc.).

By taking advantage of the advantages of non-combustibility, soundproofing, moisture-proofing, and lightness, or by using materials that were previously thought to be impossible from another point of view, and without using clay, we can create wall materials or other construction materials. The purpose of this invention is to provide a method for firing fly ash, etc., which can be used as a material.

In order to achieve the above object, the present invention employs the following means.

That is, the mixture is prepared by mixing small amounts of lime, water-soluble aluminum salts, and calcined gypsum into flyanche, etc., and adding cement if necessary, which is then hydraulically hardened, then dried and fired.

The amount of calcined gypsum or cement is required to be 5% by weight or more. If the amount is less than 5% by weight, it will not be possible to obtain sufficient strength and solidification speed.The amount of calcined gypsum or cement may be as large as it may be, but if it is too large, there will be great economic disadvantages. Of course, a mixture of calcined gypsum and cement may also be used. The mixture of lime and water-soluble aluminum salts is required in an amount of 1% by weight or more. If it is less than 1% by weight, it will not be possible to obtain sufficient solidification speed and strength, but if it is too much, there will be no economic advantage.0 The appropriate weight ratio of lime and water-soluble aluminum salt is 5:5. However, the purpose of this invention can be achieved even if there is a slight deviation from this ratio.As the lime, either slaked lime or quicklime may be used.
As the water-soluble aluminum salts, aluminum sulfate, aluminum chloride, polyaluminum chloride, natural aluminum salt (alunite), and other basic aluminum salts can be used. Cement is required for added strength, and usually Portland cement is used. Therefore, if strength is not required or weight reduction is required, there is no need to mix it in. Even if 0 strength is required, adding too much will result in degrading the quality of the fired product, and furthermore, it will be economically disadvantageous. The disadvantages will be greater.

Fly ash or the like is added in an amount of 94% by weight or less to the mixture having the above components. When the amount of fly ash, etc. exceeds 94% by weight, the amount of the above mixture decreases, making it impossible to solidify the fly ash, etc. quickly enough, and also making it impossible to obtain a solidified product with sufficient strength. do not have.

The amount of water is related to the speed of solidification, strength after solidification, and weight.

In other words, the smaller the amount of water, the faster the solidification speed and the higher the strength after solidification.In general, when only calcined gypsum is solidified, it is appropriate to use 60 to 70 parts by weight of water per 100 parts of calcined gypsum. According to the method of the present invention, it is possible to obtain a solidified product of sufficient strength and quickly even if three times the amount of water is added to the amount of calcined gypsum. That is, in this case, water is incorporated into the solidified product as crystal water. Considering this from another perspective, the volume of the solid material can be adjusted by the amount of water, and this water evaporates during drying or calcination, making it possible to obtain a very light solid material.

By this method, fly ash etc. begin to solidify in about 10 minutes, and in 30 minutes it is possible to obtain a solidified product with such strength that no molds or the like are required.

This solidified product is dried and fired, and the drying method may be natural drying or heat drying. Firing is performed at a temperature of 800°C to 1300°C for 30 minutes or more.

The higher the temperature, the greater the hardness of the fired product, but if the temperature is too high, the fly ash will melt and become glassy.Similarly, the longer the time, the better, but if it is too long, it will become brittle.

The reason why the above-mentioned mixture has hydraulic properties has not been fully scientifically elucidated, but it is thought that this is because aluminum salts stimulate the calcilum roots of limestone. Therefore, it is possible to use the calcium roots contained in cement without especially mixing lime, but in this case, the mixing weight ratio of aluminum salts and alkali metal carbonates is 3:2. However, even if there is a slight deviation from this range, the effect will not be greatly affected. As the alkali metal carbonate, soda carbonate, magnesium carbonate, etc. can be used.

〔Example〕

Table 1 shows the blending ratio and various physical properties of four examples of this invention.

Drying was carried out at 80°C for 30 minutes, bisque fired at 750°C for 10 minutes, colored with cobalt TA material, and baked at 1180°C for 40 minutes. In this case, it can be seen that the drying shrinkage rate is almost not observed and is almost unrelated to the amount of water. Further, in the case of this example, since the amount of water was intentionally increased, a large amount of crystal water was released during firing, and a very light fired product could be obtained. The fired bending strength and the raw bending strength are 10
Kg/cm”, whereas 25 Kg/cm
It was possible to obtain a fired body having a size of cm2 or a little smaller than that. However, in this case, since there is a lot of moisture, the fired bending strength is somewhat low, but it is natural that if the moisture content is reduced, a fired body with even higher bending strength can be obtained.

Moreover, the above experimental results were the same in both the first invention using limes and the second invention using alkali metal carbonates.

〔Effect of the invention〕

As explained above, this invention uses fly ash etc.
Since it can be solidified in a short time, the time required to remove the frame is short, and a fired product with sufficient strength can be obtained without using clay, making it possible to use materials that had no other use than to discard them. It can be used to obtain inexpensive building wall materials and other building materials. In addition, the method for carrying out this invention 1
It is also possible to obtain unfired architectural wall materials using one arm of the tongue, but it is already generally recognized that the deterioration of fired products over time is extremely rare. Therefore, aging of unfired products differs depending on the material, and there is a concern that it cannot be determined based on initial strength and other properties, especially when using a solid material that has never existed before, as in this invention. However, if you bake it, the above concerns can be almost eliminated.

Claims (2)

[Claims] (1) [1] Fly ash, volcanic ash, loamy soil,
At least 94% by weight of at least one of blast furnace slag, municipal waste incineration ash, sludge, and sludge incineration ash (hereinafter referred to as fly ash, etc.) [2] 5% by weight or more of calcined gypsum and/or cement [3]
1% by weight of a mixture of water-soluble aluminum salts and lime
A method for firing fly ash, etc., characterized by mixing the above, adding an arbitrary amount of water, pouring into a molding frame to solidify, removing the molding frame, drying, and further firing at a high temperature. (2) [1] Fly ash, volcanic ash, loamy soil,
At least 94% by weight of at least one of blast furnace slag, municipal waste incineration ash, sludge, and sludge incineration ash (hereinafter referred to as fly ash, etc.) [2] 5% by weight or more of cement, [3] Water-soluble aluminum salts and alkali metals. A mixture of carbonates of 1% by weight or more is mixed, an arbitrary amount of water is added, poured into a molding frame, solidified, removed from the molding frame, dried, and further fired at a high temperature. How to fire fly ash, etc.