JP2015052036A - Improvement material and improvement method for acidic sulfate soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide soil improvement material in which raw material is easily available and a stable neutralizing characteristic is exhibited for a long time, and which does not inhibit the germination and growth of a plant, and to provide a soil improvement method.SOLUTION: Improvement material is produced by using natural zeolite as main material and mixing cationic material eluting a cation other than a sodium ion. It is preferable that: the maximum grain size of the natural zeolite is less than 100 μm; cation exchange capacity is 100 meq/100 g or more; the maximum grain size of the cationic material is less than 100 μm; the cationic material is obtained by mixing easily water-soluble material and hardly water-soluble material; and an amount of the cationic material mixed in the natural zeolite is adjusted so that the amount of the cationic material does not exceed the maximum quantity acceptable as a fertilizer component. Water, a fibrous stabilizer, a thickener and a fertilizer component are added to the improvement material to be in a slurry state, and the mixed product is dispersed to the surface of acidic sulfate soil.

Description

  The present invention relates to an improving material and an improving method for acidic sulfate soil, and more particularly to an improving material and an improving method for acidic sulfate soil using natural zeolite as a main raw material.

  In construction work, when excavating a natural ground containing pyrite, white pyrite, etc., or performing embankment using excavated soil of such natural ground, the soil that was in the reduced state touches the air and oxidizes, It is known to become a strongly acidic sulfate soil. Conventionally, an artificial zeolite obtained by hydrothermal reaction of incinerated ash with sodium hydroxide is used as a method of adding an improving material to such acidic sulfate soil so as not to inhibit plant growth. A soil improvement material obtained by ion-exchange of sodium ions with a predetermined cation has been developed (see Patent Document 1).

  The soil improvement material described in Patent Document 1 is a hydrothermal reaction of artificial zeolite such as fly ash with a sodium hydroxide solution, and sodium ions contained in the artificial zeolite are converted into calcium ions, iron ions, hydrogen ions, magnesium ions. It is produced by ion exchange with cations such as potassium ions and calcium ions.

  According to such a soil conditioner, by appropriately adjusting the content of sodium ions contained in the artificial zeolite, the acidity of the soil is improved as the oxidation of the acidic sulfate soil progresses, and the germination of the plant is also achieved. And has an excellent effect of not inhibiting growth.

Japanese Patent Laid-Open No. 2007-2007

  The above-mentioned conventional soil improvement material is mainly made of artificial zeolite obtained by hydrothermal reaction of incinerated ash made of fly ash or the like with sodium hydroxide, and the incinerated ash is required to have a certain quality. However, it is often difficult to stably obtain quality incineration ash that can be used as a raw material for artificial zeolite.

  In addition, artificial zeolite with reduced sodium ions has a slightly complicated manufacturing method and requires advanced quality control, and it has been difficult to say that artificial zeolite can be easily manufactured.

  Furthermore, incineration ash such as fly ash generally contains heavy metals, but if the heavy metals are not properly removed, they may not be used as a soil conditioner.

  The present invention has been proposed in view of the above-described circumstances. In soil improvement of acidic sulfate soil, it is easy to obtain raw materials, and by exhibiting stable neutralization characteristics over a long period of time, germination of plants and It aims at providing the soil improvement material and soil improvement method which do not inhibit growth.

  The improvement material and improvement method of acidic sulfate soil of the present invention have been proposed in view of the above-described circumstances, and have the following characteristics. That is, the acidic sulfate soil improving material of the present invention is characterized in that a natural zeolite is used as a main raw material and a cation material that elutes a predetermined cation other than sodium ions is mixed therein.

  In the acid sulfate soil improving material, the maximum particle size of the natural zeolite is preferably less than 100 μm, and the cation exchange capacity is preferably 100 meq / 100 g or more.

  In addition, the cation material has a maximum particle size of less than 100 μm and is easily water-soluble (a material that is water-soluble and instantaneously ion-exchanged with natural zeolite) and a slightly water-soluble material (slowly with natural zeolite). It is preferable that the material to be ion-exchanged is mixed.

  Moreover, it is preferable that the mixing amount of the cation material into the natural zeolite is adjusted so that the cation material does not exceed the maximum amount allowed as a fertilizer component.

  In the method for improving acidic sulfate soil of the present invention, water, a fiber stabilizer, a thickener and a fertilizer component are added to each of the above-described improved materials to form a slurry, which is then sprayed on the surface of the acidic sulfate soil. It is characterized by this.

  According to the improvement material and the improvement method of the acidic sulfate soil of the present invention, natural zeolite is used as the main raw material, so that the raw material is easily available. In addition, by using a readily water-soluble cation material and a slightly water-soluble cation material, it is possible to exhibit stable neutralization characteristics over a long period from the time of spraying.

  In addition, by defining the maximum particle size of natural zeolite and cation material below a predetermined value, water, fiber stabilizers, thickeners and fertilizer components can be added and dispersed as a slurry to make it easy and uniform. Can be sprayed.

  Moreover, the germination and growth of a plant are not inhibited by adjusting the mixing amount of an improving material so that a cation material may become the range which does not exceed the maximum amount permitted as a fertilizer component.

Explanatory drawing, such as a property of the cation material used with the improvement material of the acidic sulfate soil which concerns on embodiment of this invention. Explanatory drawing of a neutralization test result. Explanatory drawing of an acid buffer test result. The schematic diagram of the pot for plant growth tests. Explanatory drawing of a plant growth test result.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 5 illustrate an improvement material and an improvement method for acidic sulfate soil according to an embodiment of the present invention. FIG. 1 is an explanatory view of the properties of a cation material used in the improvement material, and FIG. FIG. 3 is an explanatory view of the acid buffer test result, FIG. 4 is a schematic view of a plant growth test pot, and FIG. 5 is an explanatory view of the plant growth test result.

<Improved acid sulfate soil>
The acid sulfate soil improving material according to the embodiment of the present invention is manufactured by using natural zeolite as a main raw material and mixing a cationic material that elutes a predetermined cation other than sodium ions. The predetermined cations other than sodium ions are, for example, calcium ions, magnesium ions, and potassium ions.

<Cation material>
It is preferable that the cation material mixed in the natural zeolite is of two types, a water-soluble material and a poorly water-soluble material. That is, by using a readily water-soluble material, cation exchange is instantaneously performed with natural zeolite, and an immediate effect is produced as an improving material, while ion exchange is performed slowly with a poorly water-soluble material. As an improving material, it can produce an effect over a long period.

As an easily water-soluble material, for example, slaked lime (Ca (OH) ₂ ) can be used. In addition, as the poorly water-soluble material, for example, calcium carbonate (CaCO ₃ ) can be used. In addition, each material is not restricted to these, As long as the conditions as an improvement material of this invention are satisfy | filled, another material can be used.

With reference to FIG. 1, the examination result with respect to the property etc. of a cation material is demonstrated. As a result of considering the properties of the cation material, it is conceivable to use calcium chloride (CaCl ₂ .6H ₂ O) as a readily water-soluble material. It may have an adverse effect on growth, and it needs to be devised for use as a cation material. Similarly, it is conceivable to use calcium nitrate (Ca (NO ₃ ) ₂ .4H ₂ O) as a readily water-soluble material, but the nitrogen contained when used as an improving material has an adverse effect on plant growth. It may be given (excessive nitrogen content), and some ingenuity is required for use as a cation material.

Further, dihydrate gypsum (CaSO ₄ .2H ₂ O) and lime superphosphate (Ca (H ₂ PO ₄ ) ₂ .H ₂ O (40%) + CaSO ₄ (60%)) were also examined. As a result, in the present embodiment, slaked lime (Ca) is used as a water-soluble material by comprehensively considering various factors such as the elution of substances harmful to plant growth and the ease of adjustment of fertilizer components. (OH) ₂ ) was used, and calcium carbonate (CaCO ₃ ) was used as the poorly water-soluble material.

  The improved material of the present invention is made into a slurry by adding water, a fiber stabilizer, a thickener and a fertilizer component, and the slurry is dispersed on the surface of acidic sulfate soil which is the soil to be improved, thereby improving the soil. Do. For this reason, it is preferable that the natural zeolite which is the main raw material of the improved material has a maximum diameter of less than 100 μm and a cation exchange capacity of 100 meq / 100 g or more. The cation material preferably has a maximum particle size of less than 100 μm.

  In addition, the improved material of the present invention uses, for example, an acidic sulfate soil as the embankment material, and one of the purposes is to improve the strong acidity of the acidic sulfate soil so as not to inhibit plant growth. In this case, the content of fertilizer components for plant growth is an important factor. Therefore, when the cation material is mixed with natural zeolite, it is necessary to adjust the amount of the cation material so long as it does not exceed the maximum amount as a fertilizer component.

<Improvement method of acid sulfate soil>
As described above, the method for improving acidic sulfate soil according to the present invention adds water, a fiber stabilizer, a thickener, and a fertilizer component to the improved material to form a slurry, and on the surface of the acidic sulfate soil. It is something to spray. That is, by using acidic sulfate soil as the embankment material and spraying the improving material onto the acidic sulfate soil, it is possible to generate soil that does not inhibit plant growth. As the fiber stabilizer, thickener and fertilizer component, materials generally known as those used for soil improvement materials may be used.

<Neutralization test>
With reference to FIG. 2, the neutralization test result with respect to the improvement material of this invention is demonstrated. As the improvement material of the present invention, natural zeolite / 5 kg, slaked lime / 0.1 kg (2% to zeolite ratio), calcium carbonate 0.5 kg / (10% to zeolite ratio) were used as basic blends. In the production of the test body, natural zeolite / 1 kg, slaked lime / 20 g, calcium carbonate / 100 g were added as improving materials, and the mixture was stirred with a mortar mixer for 10 minutes. Moreover, concentrated sulfuric acid (36N) was diluted 2000 times as dilute sulfuric acid (0.018N), and adjusted to about pH3. And the improvement material was thrown into 5g per 1g with respect to 100 ml of dilute sulfuric acid, and the neutralization tendency was observed. Further, as a control material, a natural zeolite simple substance was also subjected to a neutralization test.

  As apparent from FIG. 2, natural zeolite alone has almost no neutralizing effect, whereas the improved material of the present invention has a good neutralizing effect.

<Acid buffer test>
The acid buffer test for the improved material of the present invention will be described with reference to FIG. The improved material of the present invention used in the acid buffer test has the composition as described above. Further, as a control material, an improved material obtained by ion exchange of artificial zeolite with a predetermined cation material was used.

  As is apparent from FIG. 3, the improved material of the present invention shows an acid buffering result almost the same as the improved material obtained by ion-exchange of the artificial zeolite used in the past with a predetermined cation material, and is effective as an acid buffer material. It turned out to be.

<Plant growth test>
With reference to FIG.4 and FIG.5, the plant growth test result with respect to the improvement material of this invention is demonstrated. In the plant growth test, a culture pot 10 as shown in FIG. 4 was used. A sprinkling pipe 11 is disposed on the top of the culture pot 10. A drip hole 12 is opened in the sprinkling pipe 11, and water 20 can be supplied from the drip hole 12. Further, a drain hole 13 is opened on the bottom surface of the culture pot 10.

  Inside the culture pot 10, from the bottom, the gravel for drainage layer is about 3 cm thick, the sand for drainage layer is about 2 cm thick, the acid sulfate soil is 750 g, the improved material of the present invention, the culture soil is 100 g: about 2 cm The layers are stacked in thickness, seeds are sown on the top surface of the culture soil, and the soil is covered so that the seeds are hidden on it.

  Then, using a culture pot 10 shown in FIG. 4, seeds of tall fescue and orchard grass were sown and a plant growth test was performed. The test results are shown in FIG. As is clear from FIG. 5, there was no significant difference in plant growth between the improved material using artificial zeolite and the improved material of the present invention. On the other hand, plant growth was inferior in the case of using the intangible soil as compared with the case of using the improved material. From this plant growth test, it was found that the improved material of the present invention exhibits a sufficient plant growth effect in the same manner of use as the improved material using artificial zeolite.

<Comparison with conventional technology>
The acidic sulfate soil improvement material of the present invention uses natural zeolite as a main raw material, and a cation material (material that elutes calcium ions, magnesium ions, potassium ions, etc. other than sodium ions) is mixed in the natural zeolite. Is.

  Natural zeolite can be stably supplied in that it is easily available compared to artificial zeolite. Also, incineration ash such as fly ash used as artificial zeolite often contains heavy metals. In this case, heavy metals must be removed, but natural zeolite requires almost no heavy metal removal work. It is. In addition, the process of ion exchange of sodium ions of artificial zeolite with other cations is somewhat complicated, but the improved material of the present invention uses natural zeolite as a main raw material and only mixes a predetermined cation material. Can be manufactured.

  In addition, as described in the acid buffer test results, the improved material using the natural zeolite of the present invention as the main material exhibits the same acid buffering effect as compared with the improved material using artificial zeolite as the main material, A sufficient plant growth effect can be obtained.

10 Cultivation Pot 11 Sprinkling Pipe 12 Drip Hole 13 Drainage Hole 20 Water

Claims (5)

  A material for improving acidic sulfate soil, characterized in that a natural zeolitic material is used as a main raw material and a cation material that elutes a predetermined cation other than sodium ions is mixed therein.   The improved material for acidic sulfate soil according to claim 1, wherein the natural zeolite has a maximum particle size of less than 100 µm and a cation exchange capacity of 100 meq / 100 g or more.   3. The acidic sulfuric acid according to claim 1, wherein the cation material has a maximum particle size of less than 100 μm, and is a mixture of a water-soluble material and a poorly water-soluble material. Salt soil improvement material.   The amount of the cation material mixed in the natural zeolite is adjusted so that the cation material does not exceed the maximum amount allowed as a fertilizer component. 4. The improved material for acidic sulfate soil according to any one of 3 above.   Using the improving material according to any one of claims 1 to 4, water, a fiber stabilizer, a thickener and a fertilizer component are added to the improving material to form a slurry, and an acidic sulfate A method for improving acidic sulfate soil, characterized by being applied to the surface of the soil.

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