JPH07232148A - Solidifying agent for treating surplus soil and surplus soil solidification treatment using the same - Google Patents

Abstract

PURPOSE:To obtain a solidifying agent which has good uniform-dispersibility into surplus soils such as slurried excavation surplus soil, etc., and is lightweight by forming the agent through blending respective prescribed pts.wt. of an aqueous polymer and a powdery natural organic substance together. CONSTITUTION:This agent is formed by blending 100 pts.wt. of an aqueous polymer and 10 to 1000pts.wt. of a powdery natural organic substance together. Such combination of the aqueous polymer and the powdery natural organic substance is appropriately selected from respective groups of water-absorbing resins, water-soluble polymers and powdery natural organic substances without imposing any particular limitation on the selection. Also, by blending the natural organic substance, the aqueous polymer is easily and uniformly dispersed into slurries. Further, since the powdery natural organic substance contains many hydrophilic groups such as hydroxyl or carboxyl group, etc., the substance has very good affinity for both the aqueous polymer and slurries. Therefore, this solidifying agent shows good dispersibility into slurries and excellent performances as solidifying agent for treating surplus soils.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solidifying agent for treating residual soil used for solidifying residual soil such as water-containing slurry excavated residual soil, sludge at sewage treatment plants, and water purification plants, and a method for solidifying residual soil using the same. .

[0002]

BACKGROUND OF THE INVENTION Solidifying agents for treating residual soil are widely used as solidifying agents for water-containing slurry-like excavated residual soil (hereinafter referred to as "slurry") generated mainly at civil engineering sites. . Conventionally, as a method for treating a slurry, a method in which a lime or cement-based solidifying agent is added and mixed, and solidified by its hydration action, or a water-absorbent resin is added and solidified, and then carried is used. There is.

However, since the residual soil after solidification of the slurry of lime or cement-based solidifying agent becomes strongly alkaline, there is a problem of environmental influence due to alkali outflow after disposal.
Further, the cement-based solidifying agent has a problem that it requires curing for several days before solidifying, which requires a facility or the like.

On the other hand, the method using a water-absorbent resin is an improved method in which these drawbacks are improved, the slurry can be solidified very quickly, and there is no problem of environmental pollution due to the residual soil after the treatment. Therefore, it has come to be used rapidly in recent years. However, when the water-absorbent resin is used alone to solidify the slurry, the added water-absorbent resin is not uniformly dispersed in the slurry, so that the portion that does not absorb water well, that is, the solidified portion and the solidified portion are not solidified. A portion is generated, and moreover, the amount of the water absorbent resin used for solidifying the slurry is large and not efficient.

Therefore, various measures have been taken to improve the dispersibility of these water-absorbent resins by using inorganic substances such as fly ash, slag, bentonite and zeolite as a carrier, and blending them with about 50% by weight. Has been done. However, since these inorganic carriers are heavy, they are problematic in terms of transportation and handling, and are not necessarily good as dispersibility improving agents in slurries.
I am not completely satisfied.

An object of the present invention is to provide a solidifying agent for treating residual soil and a method for solidifying residual soil, which has good dispersibility in the residual soil such as slurry-like excavated residual soil and is lightweight.

[0007]

Means for Solving the Problems As a result of intensive investigations in view of the above situation, the present inventors have found that water-soluble polymers such as water-absorbent resins or water-soluble polymers have rice husk powder, coconut shell powder, walnut powder, A solidifying agent for treating residual soil obtained by blending natural organic powders such as wood flour as an extender dispersant, the dispersibility of the aqueous polymer in the slurry is greatly improved, and the solidifying action of the aqueous polymer works effectively. The present invention has been completed and the present invention has been completed.

That is, the gist of the present invention is: (1) 100 parts by weight of the aqueous polymer and 10 to 1000 parts by weight of the natural organic powder are mixed to solidify the residual soil, and (2) the aqueous polymer absorbs water. (1) The solidifying agent for treating residual soil according to (1) above, which is a water-soluble polymer and / or a water-soluble polymer, (3) above, wherein the natural organic powder is rice husk powder, coconut shell powder, walnut powder or wood powder. Solidifying agent for treating residual soil of (4) residual soil, aqueous polymer and 1/10 to 1 part by weight of the aqueous polymer.
10 parts by weight of natural organic powder is added in a total amount of 0.0
5. A method for solidifying residual soil, comprising adding and mixing so as to be 5 to 2% by weight, (5) The residual soil solidifying treatment according to (4), wherein the aqueous polymer is a water-absorbent resin and / or a water-soluble polymer. The method and (6) the natural organic substance powder is rice husk powder, coconut shell powder, walnut powder or wood powder (4)
Alternatively, it relates to the residual soil solidification treatment method according to (5).

The aqueous polymer used in the present invention includes:
Usually, a water-absorbent polymer having a water-absorbing capacity of 10 to 1000 times its own weight used in commercially available paper diapers and the like, as well as a water-soluble polymer used as an aggregating agent and the like can be mentioned.

As the water-absorbent resin, a cross-linked product of an acrylate polymer, a cross-linked product of a vinyl alcohol-acrylate copolymer, a cross-linked product of maleic anhydride-grafted polyvinyl alcohol, an acrylate-methacrylate copolymer. Crosslinked product of polymer, crosslinked product of saponified methyl acrylate-vinyl acetate polymer, crosslinked product of starch-acrylate graft copolymer, crosslinked product of hydrolyzed starch-acrylonitrile copolymer, starch-acrylic Examples thereof include a crosslinked product of a saponified product of an ethyl acid graft copolymer, a crosslinked product of carboxymethyl cellulose, and a crosslinked product of polyethylene oxide.

It is preferable to use a polyacrylic acid-based water-absorbing resin such as a cross-linked product of an acrylic acid polymer, a cross-linked product of a vinyl alcohol-acrylate copolymer, a cross-linked product of a starch-acrylate graft copolymer. is there. Above all, a cross-linked product of an acrylate polymer and a starch-acrylate graft copolymer are preferably used.

As the water-soluble polymer, polyacrylamide, polyethylene oxide, polyvinyl alcohol, polyvinyl pyridine, polyethylene imine, sodium polyacrylate, guar gum, locust bingham, quince seed gum, gum arabic, sodium alginate,
Examples thereof include starch, sodium salt of carboxymethyl cellulose, gelatin, chitosan and the like. Preferred are polyacrylamide, polyethylene oxide, and guar gum.

In the present invention, these water-absorbent resins or water-soluble polymers may be used alone or in combination of two or more kinds, and may be used by mixing with the natural organic substance powder. Also,
You may use these water-absorbent resin and water-soluble polymer together.
When using a water-absorbent resin and a water-soluble polymer in combination, it is not particularly limited and is arbitrarily selected from the above,
For example, a combination of a crosslinked product of an acrylate polymer and polyacrylamide, and a combination of a crosslinked product of an acrylate polymer and guar gum are preferably used.

The natural organic powder used in the present invention includes
A crushed product of a natural organic substance powder such as rice husk powder, coconut shell powder, walnut powder, and wood powder is used. These natural organic powders are
They are used alone or in combination.

In the present invention, the combination of the above-described aqueous polymer and natural organic substance powder is not particularly limited, and is appropriately selected from the above-mentioned groups of water-absorbent resin, water-soluble polymer and natural organic substance powder. To be selected. For example, acrylate polymer cross-linked product and rice husk powder, acrylate polymer cross-linked product and wood powder, acrylate polymer cross-linked product and coconut shell powder, polyacrylamide and rice husk powder, guar gum and rice husk powder, Examples include a combination of guar gum and wood flour, a cross-linked product of an acrylate polymer, a mixture of guar gum and rice husk powder, and a cross-linked product of an acrylate polymer and walnut powder.

The lower limit of the particle size of the aqueous polymer and the natural organic powder used in the present invention is usually 10 μm,
The thickness is preferably 20 μm, and the upper limit in each case is 2 mm, preferably 1 mm. That is, for example, an average particle size of 10 μm
˜2 mm, preferably 20 μm to 1 mm, more preferably 30 μm to 0.5 mm. When the amount is smaller than this range, the mixing property of the aqueous polymer and the natural organic substance powder is good, but there is a large amount of powdering and the work environment tends to be contaminated, which is not preferable. On the other hand, if the amount is larger than this range, the mixing property of the aqueous polymer and the natural organic substance powder is deteriorated, and in some cases, the two tend to be separated, which is not preferable.

It is not clear why the aqueous polymer is easily and uniformly dispersed in the slurry by mixing the natural organic powder, but the natural organic powder contains many hydrophilic groups such as hydroxyl groups and carboxyl groups. From having
It has an extremely good affinity for both the aqueous polymer and the slurry, and thus the solidifying agent for residual soil treatment of the present invention exhibits good dispersibility in the slurry and exhibits excellent performance as a solidifying agent for residual soil treatment. It is presumed to be a thing.

Further, since the natural organic substance powder is lighter in weight than the inorganic carrier, the obtained solidifying agent for treating residual soil is also light in weight, which is advantageous in transportation and handling.

In the present invention, the lower limit of the content of the natural organic powder is 100 parts by weight with respect to 100 parts by weight of the aqueous polymer, which is usually 10.
Parts by weight, preferably 20 parts by weight, more preferably 30
The upper limit is usually 1000 parts by weight, preferably 500 parts by weight, and more preferably 300 parts by weight. For example, it is suitable to add natural organic powder in the range of 10 to 1000 parts by weight, preferably 20 to 1000 parts by weight.
The amount is 500 parts by weight, more preferably 30 to 300 parts by weight. When the amount of the natural organic powder used is less than this range, the effect of dispersing the aqueous polymer tends to be small, while when the amount of the natural organic powder is more than this range, the solidification action of the slurry becomes insufficient and a large amount of solidification occurs. It is not preferable because it is necessary to use an agent.

The slurry to which the solidifying agent for treating residual soil of the present invention is applied includes water such as excavated residual soil in the form of water-containing slurry mainly generated at civil engineering sites, sludge in sewage treatment plants, water purification plants, etc. In addition, it contains clay, silt, sand, gravel and the like.

The solidifying agent for treating the residual soil of the present invention may be prepared by mixing a predetermined amount of the aqueous polymer and the natural organic material powder by a generally known method. However, even if the mixture is not sufficiently mixed, the slurry is prepared. If this is achieved during mixing, the effect of the present invention is achieved. Therefore, in use, in addition to the method of adding and mixing the solidifying agent for residual soil treatment of the present invention prepared by previously mixing the aqueous polymer and the natural organic substance powder, the slurry is prepared by simultaneously adding both to the slurry. It is also possible to adopt a method for solidifying the residual soil that is mixed together. Preferably, the aqueous polymer and the natural organic substance powder are mixed in advance and then added to the slurry.

The amount of the solidifying agent for treating the residual soil of the present invention used for solidifying the slurry is not uniquely determined because it depends on the composition of the slurry, the properties, the water content and the type of the aqueous polymer constituting the solidifying agent of the present invention. However, for example, 100 parts by weight of clay, 100 parts by weight of silica sand (average particle size 0.3 mm), and water 2
An appropriate amount of the solidifying agent of the present invention is 0.05 to 2% by weight, more preferably 0.1 to 1% by weight, based on 100 parts by weight of the slurry. Also when adopting the method for solidifying the residual soil by simultaneously adding the aqueous polymer and the natural organic substance powder to the slurry and mixing them with the slurry, 1 / part by weight of the aqueous polymer and 1 part by weight of the aqueous polymer is used.
It is advisable to add 10 to 10 parts by weight of the natural organic powder so that the total addition amount is 0.05 to 2% by weight, preferably 0.1 to 1% by weight. If it is used in an amount less than this range, it tends to be difficult to obtain a sufficient solidifying action, and if it is used in an amount larger than this range, an effect commensurate with it cannot be obtained, which is not a good idea.

The solidifying agent for treating residual soil of the present invention and the slurry are mixed by a generally known method using a mixer, a backhoe and the like.

When the solidifying agent for treating residual soil of the present invention is used,
The solidification of the slurry varies depending on the amount used, the type of the slurry and the like and is not uniquely determined, but is usually 5 minutes, 10 minutes at the longest, and 2 minutes if it is short.

[0025]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The respective raw materials used in the examples and comparative examples are as follows.

Water-absorbent resin Crosslinked product of acrylate polymer (Aquakeep 10SH-
P, water absorption capacity 400 to 600 times: Sumitomo Seika Co., Ltd., average particle size 200 μm)

Water-soluble polymer Polyacrylamide (average particle size 300 μm) Gua gum (average particle size 50 μm)

Natural organic substance powder Rice husk powder A (average particle size 35 μm) Rice husk powder B (average particle size 200 μm) Palm shell powder (average particle size 100 μm) Wood powder (average particle size 70 μm) Walnut powder (average particle size 100 μm)

Inorganic powder zeolite (average particle size 100 μm)

Examples 1 to 10 Aqueous polymers and natural organic substance powders were mixed in the formulations shown in Table 1 to prepare a solidifying agent for treating residual soil according to the present invention. Clay 10
0 parts by weight, silica sand (average particle size 0.3 mm) 100 parts by weight,
Slurry 100 prepared by mixing 200 parts by weight of water
0 parts by weight of the above-mentioned solidifying agent for treating residual soil was added and mixed in the addition amount (% by weight) shown in Table 1, and 2 minutes and 5 minutes after mixing.
The change in the solidified state of the slurry after minutes was visually observed and evaluated. The results are shown in Table 1.

[0031]

[Table 1]

Comparative Examples 1 to 3 An aqueous polymer and an inorganic powder were mixed in the composition shown in Table 1,
A solidifying agent for treating residual soil was prepared. A solidifying agent for treating residual soil was prepared in the same manner as in Example 1 using 1000 parts by weight of a slurry prepared by mixing 100 parts by weight of clay, 100 parts by weight of silica sand (average particle size 0.3 mm), and 200 parts by weight of water. Addition and mixing with the addition amount (% by weight) described in 2) and 5 minutes after mixing
The change in the solidified state of the slurry after minutes was visually observed and evaluated. The results are also shown in Table 1.

As is apparent from Table 1, the solidifying agent for treating residual soil of the present invention uses water absorbent resin or water-soluble polymer alone (Comparative Examples 1 and 3) or uses water absorbent resin and zeolite in combination (comparative). It can be seen that the solidification rate is higher than that of Example 2) and that it is excellent as a solidifying agent.

[0034]

The solidifying agent for treating residual soil of the present invention contains a natural organic substance powder having a good affinity for both the aqueous polymer and the slurry. Therefore, the solidifying agent is added to and mixed with the slurry. In this case, the aqueous polymer is uniformly dispersed in the slurry, and the slurry can be solidified in a short time.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C02F 11/00 101 Z 7446-4D C08K 5/00 KAJ C08L 101/00 101/14 LSY C09K 17 / 20 P 17/22 P 17/32 P // C09K 103: 00 (72) Inventor Yasunori Hara 4-7 28 Kitahama, Chuo-ku, Osaka Sumitomo Seika Co., Ltd. Osaka Head Office (72) Inventor Saburo Kimura Osaka Sumitomo Kagaku Kogyo Co., Ltd. 4-53, Kitahama, Chuo-ku, Yokohama-shi

Claims (6)

[Claims] 1. A solidifying agent for treating residual soil, which is obtained by mixing 100 parts by weight of an aqueous polymer and 10 to 1000 parts by weight of a natural organic powder. 2. The solidifying agent for residual soil treatment according to claim 1, wherein the aqueous polymer is a water-absorbent resin and / or a water-soluble polymer. 3. The solidifying agent for treating residual soil according to claim 1, wherein the natural organic substance powder is rice husk powder, coconut shell powder, walnut powder or wood powder. 4. A water-based polymer and 1/10 to 10 parts by weight of natural organic powder to 1 part by weight of the water-based polymer are added to the residual soil so that the total amount added is 0.05 to 2% by weight. A method for solidifying residual soil, which comprises mixing. 5. The residual soil solidification treatment method according to claim 4, wherein the aqueous polymer is a water-absorbent resin and / or a water-soluble polymer. 6. The method for solidifying residual soil according to claim 4, wherein the natural organic substance powder is rice husk powder, coconut shell powder, walnut powder or wood powder.