JP2001310175A - Method for insolubilization treatment of boron contained in soil or incineration ash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for insolubilization treatment of boron contained in soil or incineration ash, capable of suppressing the elution of boron from soil in the vicinity of farmland or incineration ash. SOLUTION: Soil or incineration ash containing boron, for example, coal ash is solidified with blast furnace slag B cement being a solidifying material or fixed with a fixing material to suppress the elution of boron.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for insolubilizing boron contained in soil or incinerated ash (including slag), and more particularly to soil in an area where rainwater or the like flows into irrigation water or thermal power generation. The present invention relates to a method for insolubilizing boron, which is suitable for incineration ash discharged from a steel plant, a steel mill, a garbage incineration plant, or the like.

[0002]

2. Description of the Related Art In an area where boron is eluted from boron-containing soil and mixed with irrigation water, it is known that plants ingest a large amount of boron and inhibit the growth of the plants. Therefore, it is thought that boron insolubilization technology will play an important role in areas where the soil containing boron is hinterland.

On the other hand, in a thermal power plant, a steel mill, a garbage incineration plant and the like, a large amount of incinerated ash is landfilled, and this incinerated ash also contains boron, which elutes and has an adverse effect on plants. I am worried. In addition, there is a shortage of landfill sites for landfilling incineration ash, and it is desired to effectively use incineration ash, a by-product, in order to reduce the environmental impact of increasing the number of disposal sites.

[0004]

However, conventionally, no insolubilization treatment of boron contained in soil or incineration ash has been performed, so that boron is eluted from these soils or incineration ash, and irrigation water and the like are removed. A large amount of boron would flow into farmland through the plant, and there was a risk that agricultural products would be damaged. In addition, incineration ash containing boron is
It was difficult to use it effectively, and we had to discard it.
Problems with disposal due to restrictions on landfill sites remained.

[0005] Therefore, the present invention can suppress the elution of boron from soil near the irrigation canal or incineration ash discharged from a thermal power plant or the like, thereby preventing the growth failure of agricultural products due to boron. In addition, an object of the present invention is to provide a method for insolubilizing boron contained in soil or incinerated ash in which incinerated ash can be effectively used.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for insolubilizing boron contained in soil or incinerated ash, and is constituted as follows in order to solve the above-mentioned technical problems.
That is, the present invention is characterized in that the elution of the boron is suppressed by solidifying the soil or incinerated ash containing boron with a solidifying material or fixing with a fixing material.

As the solidifying material, at least one of a calcium-based material, an alkali material, amorphous alumina, and activated alumina can be used. Further, as the fixing material, at least one of zeolite, allophane, and bentonite can be used. When the soil or the incineration ash contains a solidified material or a fixing material, it can be solidified or fixed by heating.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the method for insolubilizing boron contained in soil or incinerated ash according to the present invention will be described below in detail with reference to the drawings.

According to the present invention, there is provided a method of solidifying boron-contaminated soil or incinerated ash containing boron discharged from a thermal power plant, a steel mill, a garbage incinerator, or the like with a solidifying material, or fixing with a fixing material. This suppresses the elution of boron. Here, the incinerated ash includes slag.

[0010] The solidified material or the fixing material is usually added separately to the soil or incinerated ash and mixed therewith, but it may be originally contained in the soil or incinerated ash. In this case, it is not necessary to add it separately. It can be solidified simply by adding water to soil or incinerated ash and heating.

As the solidified material, a calcium-based material, an alkali material, a material containing amorphous alumina or activated alumina can be used. Among them, calcium-based materials include cement, lime, gypsum, calcium carbonate, and the like, and these materials are expected to have their own solidifying action.

In addition, although there are relatively many solidifying materials which do not solidify unless an alkali stimulus is applied, such materials are those which apply an alkali stimulus to such a material, that is, alkali materials which can serve as an auxiliary for the solidification action. Examples include soda ash, caustic soda, caustic potassium, and sodium silicate.

Materials containing amorphous alumina or activated alumina include sodium aluminate, potassium aluminate, blast furnace slag, paper incineration ash, municipal waste incineration ash,
There are sewage sludge incineration ash, coal ash, zeolite, allophane, bentonite and the like.

Of these, sodium aluminate and potassium aluminate are said to have an effect as a solidification aid. Blast furnace slag, papermaking incineration ash, municipal garbage incineration ash, sewage sludge incineration ash, and coal ash contain boron but have a solidifying action by itself. Furthermore, zeolites, allophane and bentonite have a sticking action.

These solidifying materials and fixing materials can be used alone, but a plurality of types can be used in combination according to the characteristics of soil or incinerated ash. These solidifying or fixing materials are usually added to the soil or incineration ash to be solidified together with water and mixed. Then, it is cured by curing at a room temperature or a high temperature by heating for a certain period. If the above-mentioned solidified material is contained in the soil or incineration ash to be solidified, water is added to the soil or incineration ash and the mixture is cured at room temperature or high temperature by heating for a certain period of time to solidify or fix. can do.

On the other hand, incinerated ash contains quicklime, but may also contain pozzolanic substances which solidify by reacting with water. In this case, by heating the incinerated ash in a state of being dissolved in water from room temperature to 200 ° C., the solidification reaction can be accelerated and solidified without adding a solidified material separately.

When this boron insolubilization method is applied to soil near irrigation water, it can be implemented by shallow layer stabilization. This shallow layer stabilization processing
Generally, the process is performed for a few meters below the ground surface. For example, the above-mentioned solidified material can be mixed with the soil using a tractor or the like.

Further, when the present invention is applied to incinerated ash discarded in the sea from a thermal power plant or the like, it can be implemented by a deep mixing method. The deep mixing method is a method of solidifying the deep part of the ground for the purpose of ground improvement, etc., for example, by inserting a nozzle into incinerated ash in the sea, and spraying a solidified material, such as cement milk, etc. horizontally from this nozzle. The incineration ash can be solidified.

When heating the soil or incinerated ash, the heater itself is driven into the soil or incinerated ash,
Alternatively, it is possible to indirectly heat the H-shaped steel by driving the H-shaped steel into a soil or incineration ash and heating the H-shaped steel with a heater.

[0020]

EXAMPLE 1 As shown in FIG. 1, a coal ash 11 containing boron discharged from a thermal power plant is put into a mixer 10, and a blast furnace slag B cement 12 is added as a solidifying material. In addition, the stirring blade 14 was rotated to perform curing for 7 days. Then, as a result of performing a boron elution test based on the notification of the Environment Agency No. 46, a result as shown in FIG. 2 was obtained.

As can be seen from FIG. 2, when the blast furnace slag B cement 12 was not blended as a solidifying material, the amount of boron eluted from the coal ash 11 was 7.81 mg / l. As the ratio increased, the boron elution amount decreased, where it could be reduced by up to 95%. In addition, blast furnace slag B cement 12
It can be seen that the uniaxial compressive strength increases as the blending ratio of becomes higher. As described above, the generated ash can be effectively used by repairing the ground of the coal ash during storage and insolubilizing the generated ash containing boron.

[0022]

Embodiment 2 As shown in FIG. 3, after adding water to such an extent that coal ash 15 containing a pozzolanic substance is saturated, a mold (form) 1
6 and placed in a drying oven 17 and heated at about 80 ° C. for 28 days. Thereafter, as a result of a boron elution test based on the Environment Agency Notification No. 46, it was confirmed that boron elution was suppressed as shown in FIG. In this example, the elution amount of boron was reduced by about 77%.

[0023]

As described above, according to the present invention,
Since the incineration ash discharged from thermal power plants and the elution of boron contained in the soil behind the farmland can be suppressed, it is possible to prevent boron from being excessively taken into agricultural products via irrigation water, This can prevent agricultural damage.

Further, according to the present invention, it is possible to effectively utilize generated ash by repairing the ground of coal ash during storage and insolubilizing generated ash containing boron. This eliminates the need for smelting, so that costs can be reduced and the increase in incineration plants can be suppressed, which is environmentally advantageous.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention.

FIG. 2 is a diagram showing test results of the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a second embodiment of the present invention.

FIG. 4 is a diagram showing test results of a second example of the present invention.

[Explanation of symbols]

 11 Coal ash (incineration ash) 12 Blast furnace slag B cement (solidified material) 15 Coal ash containing pozzolanic substances (incineration ash)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // (C04B 28/00 C04B 7:14 7:14 22:08 A 22:08 Z 22:06 Z 22 : 06 14:10 Z 14:10 14:04 Z 14:04 14:30) 14:30) 103: 60 103: 60 111: 20 111: 20 B09B 3/00 ZAB (72) Inventor Takeshi Ishiguro Tokyo (10) Maeda Construction Industry Co., Ltd., 2-10-26 Fujimi, Chiyoda-ku (72) Inventor Katsuhiko Hayashi Inside (2) Maeda Construction Industry Co., Ltd. 2-10-26, Fujimi, Chiyoda-ku, Tokyo 2-10-10 Fujimi Maeda Construction Industry Co., Ltd. F-term (reference) 4D004 AA36 AA41 AA43 AB05 AC07 CA15 CA22 CA45 CB27 CB32 CC03 CC11 CC13 4G012 PA01 PA26 PA35

Claims (4)

[Claims] 1. Boron contained in soil or incinerated ash, characterized in that the soil or incinerated ash containing boron is solidified by a solidifying material or fixed by a fixing material to suppress the elution of the boron. Insolubilization treatment method. 2. The solidifying material includes at least one of a calcium-based material, an alkali material, amorphous alumina, and activated alumina, and the fixing material includes at least one of zeolite, allophane, and bentonite. The method for insolubilizing boron contained in soil or incinerated ash according to claim 1, comprising: 3. The method according to claim 1, wherein when the solidified material or the fixing material is contained in the soil or the incinerated ash, the soil or the incinerated ash is solidified or fixed by heating the soil or the incinerated ash. 3. The method for insolubilizing boron contained in soil or incinerated ash according to 2. 4. The soil or incineration ash according to claim 1, wherein the incineration ash is incineration ash discharged from a thermal power plant, a steel mill, or a garbage incineration plant. A method for insolubilizing boron contained.