JPH0160312B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for solidifying various types of incineration ash, particularly fly ash and slag, and a solidifying additive. [Conventional Example and its Problems] Coal incineration ash produced in thermal power plants is discarded without being able to be used for much other than a small amount of it being mixed with cement. Furthermore, the incinerated ash generated at municipal waste incinerators and the waste EP ash that collects in electrostatic precipitators contain harmful substances, so they are of no use value and are discarded. Furthermore, not only is volcanic ash soil completely left unattended, but if the land used for road construction is volcanic ash soil, work must be done to remove the volcanic ash soil and replace it with compact soil. . In addition, blast furnace slag is mixed into cement,
Although it is used as a hearth material, there was no use that would give it higher added value. [Means for Solving the Problems] This invention was proposed in view of the above-mentioned conventional circumstances, and it is possible to use various types of incinerated ash such as fly ash and blast furnace slag (hereinafter simply referred to as various types of incinerated ash, etc.). The purpose of this invention is to obtain a solidification method and a solidification additive, and also to open the way to use various types of incineration ash as building materials and increase its value. In order to achieve the above object, the present invention employs the following means. That is, the method utilizes the phenomenon that when lime, aluminum salts, and sodium carbonate salts are mixed into various types of incineration ash in small quantities, water is added, and the mixture is stirred, the mixture solidifies in a short period of time. As the lime, quicklime and slaked lime can be used; as the aluminum salt, aluminum sulfate, aluminum chloride, polyaluminum chloride, aluminum nitrate, etc. can be used; as the sodium carbonate salt, sodium carbonate ( (soda ash), sesquibicarbonate soda, bicarbonate soda, etc. can be used. Also, instead of this carbonate soda salt,
Potash carbonate can also be used. The solidification phenomenon by the above method can be increased in strength by mixing hydraulic cement such as Portland cement, and early strength can be obtained by further adding alumina cement. . Moreover, the above mixture can be prepared by adding water.
It solidifies itself and can be used as a solidifying agent for soil, mud, sand, etc. by mixing the mixture with water and adding water. [Function] Table 1 shows quicklime, slaked lime, aluminum sulfate,
Soda ash, Portland cement, alumina cement and at least one of them in the fly ash
This figure shows the solidification state when the mixture was mixed at a ratio of 93:7, water was mixed at a weight ratio of 85 parts to 100 parts of the mixture, stirred, and then allowed to cure for 24 hours. The minimum amount of addition needed to solidify flyash is three types of substances: quicklime or slaked lime, aluminum salts such as aluminum sulfate, and carbonate soda salts such as soda ash. It can be seen that the strength is increased by using . Other experiments have confirmed that fly ash hardens over a long period of time even without using soda ash. However, when soda ash is mixed in, the flyash solidifies almost instantly. The smaller the amount of water, the faster it will solidify, but if it is too small and the whole product is dry, it will not solidify. Also, if there is too much, it will take a long time to solidify. Therefore, the amount of water may be adjusted depending on the situation at the site where this solidified material is used.

[Table] The amount of lime is suitably 20 to 30% by weight of the solidifying additive (lime + aluminum sulfate + soda ash), but is not particularly limited. For example, as described below, the amount of lime can be increased to obtain a coagulated body mainly composed of lime. The ratio of aluminum sulfate to soda ash is also related to solidification rate. The optimum value is 5:3 to 3:2 (weight ratio)
However, outside this range, the solidification rate becomes extremely slow. The ratio of solidification additive (aluminum sulfate + soda ash + lime) to fly ash is [3:97] ~
[10:90] (weight ratio) is appropriate. However, the upper and lower limits of the amount of solidification additive are not particularly limited, and if you want to increase the solidification rate, you can increase the amount of solidification additive, and conversely, if you want to slow down the solidification rate, you can increase the amount of solidification additive. All you have to do is reduce the amount. It can be naturally predicted that if Portland cement or alumina cement is mixed into a mixture of solidification additives (aluminum sulfate + soda ash + lime) and fly ash, the speed of solidification can be increased, and furthermore, the amount of Portland cement mixed in can be increased. The more it is, the stronger it becomes. The case where each substance constituting the solidifying additive is a powder has been described above, but among the substances constituting the solidifying additive, aluminum sulfate may be made into an aqueous solution and used as follows. That is, fly ash or the like is mixed with a solidification additive not containing aluminum salt in arbitrary amounts, and an aqueous aluminum sulfate solution of an arbitrary concentration is added. This method has a faster solidification rate than using powdered aluminum sulfate, so for example, concrete cracks are first filled with a solidifying agent such as fly ash in the form of a paste mixed with water, and then an aqueous solution of aluminum sulfate is added. It is used by impregnating the outer cracks. Examples of mixing ratios of each substance that are considered appropriate in carrying out this method are as follows. That is, 3-10% by weight of a mixture of 80% lime and 20% soda ash and 90%-90% fly ash.
A solidifying agent mixed with 97% by weight was obtained, and the solidifying agent 35 to
40% by weight is mixed with 50% by weight water to form a paste, the paste is further inserted into the cracks of the concrete, and 10-15% by weight of aluminum sulfate with a molar concentration of 8% is injected. It is.
Furthermore, 25 to 35% by weight of the above lime and soda ash mixture
65-75% by weight of Portland cement may be added to. In the above explanation, only the case of solidifying fly ash was explained, but the result is the same even if other incineration ash or blast furnace slag is used instead of fly ash. The result is the same even if I use .
However, the degree of hardening can be increased by crushing blast furnace slag into powder. In the above explanation, the solidification of fly ash and slag has been explained, but the solidifying additive or a mixture of fly ash and/or slag and solidifying additive can be mixed in an appropriate amount with soil, sludge, mud, etc. Adding water can also solidify soil, sludge, mud, etc. The above soil etc. also includes silica sand. Therefore, for example, it is also possible to form a mold. Further, the above-mentioned slag also includes stainless steel slag. When stainless steel slag is added, the solidification rate is faster than that of blast furnace slag, and the solidification strength is increased. The mixing ratio of each substance at this time may be in accordance with the above. In the above-mentioned solidification additive, if a large amount of lime is used and the mixing ratio of fly ash or slag is reduced, white walls of buildings can be provided. In the above, aluminum salts of other strong acids such as aluminum chloride and polyaluminum chloride can be used as the aluminum sulfate. In addition, other carbonates such as sodium bicarbonate, sodium sesquiate, etc. can be used for the soda ash. The above description is confirmed by experiments conducted by Associate Professor Masashi Kamon, Faculty of Engineering, Kyoto University [Japan Society of Materials Science (21st
Scheduled to be presented in Sapporo (June 10, 1986). Example 1 Fig. 1 shows the solidification strength depending on the difference in the addition rate when the solidification additive according to the present invention is added to fly ash and slag. In this case, the fly ash should be treated with the solidification additives listed in Table 2 A below, and
Solidifying additive B is used for the slag.

[Table] Since the powder slag has a brane of 4000 cm ² /g, it has a high short-term strength. Even in the case of coarse slag, a strength of 1 Kgf/cm ² or more was obtained after 3 days of curing when the solidification additive was added at a rate of 8% or more, demonstrating the effectiveness of the hardening stimulation effect of the solidification additive. Incidentally, coarse slag with no data shown was insufficiently solidified. On the other hand, there are differences in effectiveness depending on the type of fly ash, and in an example using domestic coal, a short-term strength of 1 Kgf/cm ² or more was obtained even with the addition of a small amount of solidification additive, and coarse grain Contrary to the case of slag, the solidification effect of imported coal is inferior to that of solidification additives. Figure 2 shows a summary of the water content ratios of these samples. Compared to slag,
This indicates that the fly stock has low liquidity. Next, Figure 3 examines the possibility of short-term treatment of volcanic ash and volcanic ash clay soil. Since the activity of the silica component contained in natural pozzolanic materials is low, the short-term strength is generally low. However, after 7 days of curing, Kagoshima volcanic ash showed a strength of 0.5 Kgf/cm ² or more when 5% or more of the solidification additive was added, and a certain solidification effect was obtained. The relationship between the plasticity index (1p) and strength of these samples is shown in Figure 4, and as the IP decreases, the solidification strength of the volcanic ash clay increases. Embodiment 2 This invention not only makes it possible to solidify substances such as soil and sludge that do not solidify as they are, but also allows it to be mixed into hydraulic substances such as plaster of Paris. It may also serve as a bulking agent for the substance. Conventionally, when calcined gypsum is hardened by adding water, it has been used as a building material, especially for wall plasterboards, because of its considerable strength and light weight. However, since calcined gypsum is obtained by heating dihydrate gypsum, it has the disadvantage of being expensive, and attempts have been made to use various fillers, but adding fillers lowers the value but reduces the strength. There was a point where it fell off and became unsuitable as a wall material. Therefore, the solidifying additive according to the present invention is mixed as an extender for calcined gypsum. That is, fly ash or (and) slag 10~
Mix 10 to 90% by weight of calcined gypsum with 90% by weight, and add the above solidifying additives (lime + sulfate +
3 to 20% by weight of soda) is added. The greater the amount of calcined gypsum, the better the hardness can be maintained, but there is a disadvantage in terms of price. When slag is used, it hardens at a sufficient speed and to a sufficient degree of hardness even without mixing the above-mentioned soda. Therefore, when using slag, it is advantageous in terms of cost to omit the above-mentioned soda in the solidification additive. As described above, the solidifying agent (solidifying additive + fly ash, etc.) according to the present invention can also be used as an extender for gypsum. However, even when only this solidification additive is added to the calcined gypsum, the solidification rate of the calcined gypsum can be significantly increased. Example 3 Table 3 shows C-class blast furnace cement (slag 70% by weight,
3 shows pseudo-setting, setting (initiation and completion) time, and mortar strength when the setting additive according to the present invention is added to Portland cement (30% by weight). The solidification additives B ₁ and B ₂ are mixed in the proportions shown in Table 4.

【table】

[Table] As is clear from Table 3, when the amount of water used is kept approximately constant, when the solidification additive according to the present invention is added, the solidification rate is much faster than that of cement alone. It can be seen that the strength of each type of mortar is comparable to or even higher than that of a single type of mortar. Example 4 Figure 5 a, b, and c show portland cement,
Type B blast furnace cement (50% by weight of Portland cement, 50% by weight of blast furnace slag) or Type C blast furnace cement (30% by weight of Portland cement, blast furnace slag)
This is a comparison of the strength after solidification when the solidifying additive (the mixing ratio of B shown in Table 2) was added to the solidifying additive (70% by weight) as shown in Table 5 and when it was not added.
In this experiment, in addition to cement, aggregate and water were mixed in the proportions shown in Table 6. (This experiment was conducted by Mr. Manabu Fujii, an assistant professor at Kobe University.) As can be seen from this figure, when using any type of cement, the compressive strength is lower than the solidification additive of this invention by several weight percent. The compressive strength is greater when added. Further, as shown in FIG. 5a, the solidification additive (lime + aluminum salt + soda ash) according to the present invention is also effective in increasing the early strength of cement alone.

【table】

【table】

〔Effect of the invention〕

As described above, this invention has a simple structure that uses lime, aluminum salt, and carbonate, and can solidify various types of incinerated ash, volcanic ash, slag, or mixtures thereof almost instantly. It is extremely effective in disposing of incinerated ash, etc., and furthermore, various incinerated ash, etc. can be used for buildings and structures. Furthermore, the solidification additive according to the present invention is soil,
Since it can solidify sludge, mud, etc., it can also be used to solidify mud produced in large quantities at construction sites, or sludge from rivers and the sea. Furthermore, the solidifying additives (lime+aluminum salt+soda ash) are also effective in increasing the early strength of lime.

[Brief explanation of drawings]

Figure 1 is a graph related to slag or fly ash showing the relationship between the amount of solidifying additive added and strength, Figure 2 is a graph showing the relationship between water content and strength, and Figure 3 is a graph showing the relationship between the amount of solidifying additive added and strength. A graph of volcanic ash showing the relationship between the plasticity index and Figure 4.
A graph regarding volcanic ash showing the relationship between 1p and short-term strength, and Figure 5 is a graph showing the relationship between compressive strength and number of days.

Claims (1)

[Claims] 1. A solidifying additive for various types of incineration ash, etc., which is a mixture of lime, aluminum salt, and sodium carbonate salt in arbitrary amounts. 2. The solidification additive for various types of incineration ash, etc., as set forth in claim 1, which is mixed with any amount of cement such as Portland cement or alumina cement. 3. It is characterized by mixing arbitrary amounts of lime, sodium carbonate salts, various types of incineration ash, etc., kneading the mixture with water to form a paste, and injecting an aqueous solution of aluminum salt at an arbitrary concentration into the paste. Methods for solidifying various types of incineration ash, etc. 4. The method for solidifying various types of incineration ash, etc. according to claim 3, wherein any amount of Portland cement or alumina cement is mixed into the above-mentioned whole mixture.