JP3274376B2 - Agglomerating agent for mud, solidifying agent using it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flocculating agent for muddy substances and a solidifying agent using the same, and more particularly, to a solidifying method capable of rapidly and firmly solidifying hydrous contaminants to be solidified. The present invention relates to an agent and an aggregating agent for a mud, which is a main component thereof.

[0002]

2. Description of the Related Art In order to solidify and stabilize easily spillable soil, soft ground soil, sludge and sludge, manure sludge from livestock farms (hereinafter collectively referred to as hydrated sludge),
Conventionally, various solidifying agents have been introduced into these hydrous muddy materials for treatment. Generally, a cement-based solidifying agent is mainly used for the solidification treatment of an inorganic hydrous mud, and for an organic hydrous mud,
Lime-based solidifying agents are used.

[0003] However, the cement-based solidifying agents that have been used in the past, when organic mud such as manure and sludge are mixed in the mud to be treated, the hydration-hardening reaction of cement is inhibited. In effect, the function as a solidifying agent may be lost. And the above-mentioned hydration hardening reaction becomes difficult to progress as the amount of the organic component in the target mud increases, so this cement-based solidifying agent is, for example, completely unlike dredged sludge or livestock sludge. It does not exhibit a solidifying effect as good.

On the other hand, in the case of a lime-based solidifying agent, there is a problem that alkali is eluted from a treated material after solidification, and from the viewpoint of environmental protection, it is hardly used at present except in special fields. is there. Further, the conventional solidifying agents also have the following problems. That is, for example, heavy metal ions or odor sources dissolved in the water of the mud cannot be fixed.
The re-elution of these harmful substances is likely to occur.

[0005] Recently, a solidifying agent containing fly ash as an active ingredient has been known. For example, in the case of fly ash, its specific surface area is very large, and when it is put into a hydrated mud, it disperses colloidally in the hydrated water and simultaneously causes a hydration reaction with water in the hydrated mud. To take in the water, and at least to the surface part, ettrigite (3CaO.Al ₂ O ₃ .3CaSO _4.
32H ₂ O) and calcium silicate hydrate are formed while self-hardening.

As is apparent from the above chemical formula, a large amount of water is required for producing ettringite, and a large amount of water is required for producing calcium silicate hydrate. And, since these waters necessary for the above-mentioned hydration reaction are compensated by the water in the hydrated mud, the water in the hydrated mud is absorbed and at the end of the hydration reaction, The solids in the hydrated mud solidify in an agglomerated state.

In the course of this hydration reaction, the above-mentioned hydrated compound is formed while absorbing and removing water contained in the water-containing mud, and furthermore, it is formed while involving the solid content of the mud. Eventually, porous aggregates having a structure in which the solid content and the formed hydrate compound are complexed are formed. In addition,
Fly ash is a useful aggregating agent in that the hydrated mud to be treated exhibits the above-mentioned effects even when it is inorganic or organic.

[0008] However, according to the experience of the inventors,
Even if the types and amounts of other ingredients and the amount of fly ash are the same, even if the solidifying agent is the same, for example, is it fly ash obtained from imported coal, or fly ash obtained from domestic coal? As if
If the type of fly ash is different, there is a problem that the solidifying action of the solidifying agent is different.

Therefore, in the case of producing a solidifying agent having a certain performance using fly ash as an active ingredient, it is necessary to use fly ash having certain properties obtained from a certain raw material. This is to narrow down the choice of fly ash to use,
It is not industrially preferable.

[0010]

DISCLOSURE OF THE INVENTION The present invention relates to the above-mentioned problems in the aggregating agent which constitutes a conventional solidifying agent which comprises fly ash as an active ingredient and agglomerates and solidifies the solid content of a hydrous mud. In other words, the problem that the solidifying action of the solidifying agent changes depending on the type of fly ash,
It is an object of the present invention to provide a flocculant capable of exhibiting a specific performance even when any fly ash is used, and a solidifying agent using the flocculant.

[0011]

Means for Solving the Problems The present inventors have paid attention to the following points in the course of intensive studies in order to achieve the above object. That is, first, the action and effect of the fly ash in the solidifying agent is based on the production of ettringite and calcium silicate hydrate by a hydration reaction with water in the hydrous mud, and ,
This hydration reaction is based on the idea that Ca, Si, and Al components required for the production of the ettringite and hydrate must be present in the reaction system.

[0012] Also, fly ash in a word,
This means that the composition varies depending on the type of starting material. For example, fly ash is generally composed mainly of SiO ₂ and Al ₂ O _3, and additionally contains CaO, M
Although components such as gO and Fe ₂ O ₃ are also contained, it is a fact that some types contain only about 2 to 3% by weight of a Ca component necessary for the production of ettringite.

On the basis of these points of interest, the present inventors, when selecting fly ash of a certain composition as the fly ash to be used, determine the composition and the necessary ethridite and calcium silicate hydrate to be produced. Compare the types and amounts of the components, and if the composition of the selected fly ash is less than the types and amounts of the above-mentioned necessary components, in order to satisfy the shortage, the material containing the above-mentioned necessary components The idea was that a reaction system required for the above-mentioned hydration reaction could be formed by adding a predetermined amount to the selected fly ash.

[0014] Then, when various experiments were conducted based on this idea, it was confirmed that the idea was correct, and it was found that this was applicable not only to fly ash but also to various types of incinerated ash. Was. Further studies based on this finding have led to the development of the muddy aggregating agent of the present invention and the development of a solidifying agent using the same.

That is, the agglomerating agent for a mud according to the present invention comprises:
The incineration ash is the main component.
, Natural minerals mainly composed of alumina and silicate,
Uniform blend of potassium metal carbonate and anionic surfactant
And the Si component is SiO _Two45 to 55 weight in equivalent
%, Al component is Al_TwoO_Three20-30% by weight, C
a component is 5 to 15% by weight in terms of CaO, and Mg component
5 to 15% by weight in terms of MgO
It is characterized by. In the present invention, the aggregates described above
30 to 100 parts by weight of cement per 100 parts by weight of agent
Is provided, and a solidifying agent is provided.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the aggregating agent of the present invention will be described. Dan granulating agents of the present invention is composed mainly of ash, as a whole composition, Si component in the SiO ₂ equivalent amount 4
5 to 55% by weight, and the Al component is 20 in terms of Al ₂ O _3.
-30% by weight, and the Ca component is 5-15% in terms of CaO.
% By weight, Mg component is 5 to 15% by weight in terms of MgO
It is characterized by being contained. In addition, Fe, Ti,
K, Na, etc. are Fe ₂ O ₃ , TiO ₂ , K ₂ O, N
It may be contained in the form of a ₂ O, in which case, it is preferable that the content thereof is about 1 to 2 wt%.

When the Si component, the Al component, the Ca component, and the Mg component all have the above-mentioned contents, the hydration reaction proceeds smoothly with coexisting water, such as ettringite or calcium silicate water. The product is reliably formed, and an excellent water absorbing effect is exhibited. If the composition ratio of any one of the above-mentioned components is out of the above-mentioned range, the above-mentioned hydration reaction does not proceed sufficiently, and a decrease in the water absorption effect is observed.

No incineration ash satisfies the above composition by itself, and it is difficult to satisfy the above composition by mixing various types of incineration ash. Therefore, in the present invention, a predetermined amount of each of gypsum, silica fume, a natural mineral mainly composed of alumina and silicate, an alkali metal carbonate, and an anionic surfactant is blended with incineration ash having a certain composition. It is a new technical content to mix uniformly and to adjust the content of the Si component, Al component, Ca component, and Mg component in the obtained mixture to the above-mentioned range, and to exert the function of each of the above-mentioned components at the same time. There is.

Examples of the incineration ash as a main component include various types of fly ash, incineration ash of papermaking sludge, blast furnace slag, and incineration ash of dust. Of these, incinerated ash of city garbage is not preferable because various heavy metals and the like may be mixed, and incinerated ash of fly ash or papermaking sludge is preferred. Here, gypsum is a supply source of the Ca component, which contributes to the improvement of the water absorbing action based on the above-mentioned hydration reaction and also contributes to the solidification of the formed aggregates. Gypsum, hemihydrate gypsum, dihydrate gypsum and the like can be mentioned.

Silica fume is a source of the Si component, and since it is amorphous, it is strongly crystallized when coexisting with water and combines with other components such as incineration ash to improve the strength of aggregates formed. Contribute to. Alumina-silicate-based natural minerals are amphoteric compounds that initially suspend in water upon contact with water, then dissolve over time, and as the dissolution proceeds, water is in the acidic region In this case, it exists as a cation, and when it is in the alkaline region, it exists as an anion, and exhibits its own ion exchange ability. Therefore, for dissolved pollutants such as metals and cyanide and organometallic components dissolved in water in the form of ions, for example, exerts the effect of sorbing and fixing them,
At the same time, as the dissolution progresses,
Contributes to the formation of aggregates.

Further, this natural mineral contains various kinds of mineral trace elements (mineral components), and these mineral components elute in water over time. And when the organic matter of the aqueous solution is present in the water, the eluted mineral components act on dissolved oxygen or dissociated acid ions in the water that oxidizes and decomposes the organic matter, and a part of the mineral component forms a salt with the organic matter. Binds, thereby converting the water-soluble organic matter into a coagulate that is hardly soluble in water, and promotes the separation of the organic matter component. Further, the re-elution in the separated sludge is suppressed.
The above-mentioned effects of the mineral component are particularly useful for the treatment of a water-containing mud containing an organic substance whose decay has progressed.

Examples of such natural minerals include montmorillonite, pyrophyllite, kaolinite, halloysite, salicite, maconite, and paragonite. Examples of the alkali metal carbonate include calcium carbonate, sodium carbonate, magnesium carbonate, etc., which dissolve immediately upon contact with water to neutralize the reaction system, and at the same time, for example, convert Si ⁴⁺ from incinerated ash. By contributing to the hydration reaction by promoting the elution of reactive ions such as Al, Al ^{3+ and the} like, it contributes to the improvement of the solidification action. In particular, calcium carbonate is Ca
It is also a source of components and is preferred.

Anionic surfactants include incinerated ash,
It is a component for increasing the wettability between each of the above-mentioned additional materials and water so that the above-mentioned functions and effects of the respective materials can be sufficiently exhibited. For example, sodium laurate, calcium laurate, sodium caprylate, potassium caprylate, sodium nonanoate, potassium nonanoate, and the like can be given.

The amount of the anionic surfactant may be about 0.3 to 0.6 parts by weight based on 100 parts by weight of the total amount of other components. The aggregating agent of the present invention is prepared as follows. First, incineration ash having an arbitrary composition is selected. The incineration ash may be of one type or a mixture of two or more types.

Then, the composition of the incinerated ash is analyzed, and the contents of the incinerated ash as oxides of the Si component, the Al component, the Ca component, and the Mg component are determined. Next, the above-mentioned materials are added to the incinerated ash and mixed. In that case, the addition amount of each material depends on the Si component, Al component, C component in the overall composition after mixing.
It is determined by calculation such that each of the a component and the Mg component has the above-mentioned weight ratio.

Although it depends on the type of incinerated ash,
When the incinerated ash is, for example, fly ash, 40 to 80% by weight of the fly ash, 1 to 10% by weight of gypsum, 1 to 10% by weight of silica fume, 1 to 10% by weight of calcium carbonate, 1 to 10% by weight of montmorillonite, A surfactant uniformly mixed with 0.3 to 0.6% by weight of the ionic surfactant is preferable since it has an excellent solidifying effect on a hydrated mud.

Next, the solidifying agent of the present invention will be described.
The solidifying agent of the present invention is obtained by uniformly mixing 30 to 100 parts by weight of cement with 100 parts by weight of the above-mentioned aggregating agent. Cement functions to enhance the strength of the aggregate formed of the aggregate agent and the hydrous mud, and specific examples thereof include Portland cement and early-strength cement.

The amount of cement is selected in consideration of the affinity with the target mud, but if the amount of cement is less than 30 parts by weight, the above-mentioned effects are not sufficiently exerted, and 100 parts by weight. If the number is larger than the number of parts, the solidified material becomes excessively hard. For example, when the hydrous mud is soil of soft ground, the soil after the treatment becomes too hard, which may cause difficulty in the subsequent construction work.

[0029]

【Example】

Example 1 (1) Preparation of Agglomerating Agent First, fly ash having the properties shown in Table 1 was prepared as incineration ash. In addition, anhydrous gypsum (CaS
O ₄ ), montmorillonite (Al _5/3 Mg) as a natural mineral
_1/3 Si ₄ O ₁₀ (OH) ₂ W _1/3 · mH ₂ O) and calcium carbonate (CaCO ₃ ) as an alkali metal carbonate were prepared.

Next, anhydrous gypsum, silica fume (SiO ₂ ) montmorillonite, calcium carbonate, and an anionic surfactant were added to the fly ash to obtain a granulating agent having the properties shown in Table 1. The calculation of the addition amount of each material described above is performed as follows. The case of the Ca component will be described.

Now, let the amount of fly ash be a₀, Anhydrous stone
Plaster, silica fume, montmorillonite, calcium carbonate
And the amount of anionic surfactant to be added, respectively,₁,
a_Two, A _Three, A_Four, A_FiveAnd And the aggregating agent to manufacture
Of Si component in_TwoTarget value as b₁(%)
And At this time, the following relationship is established. CaO content in fly ash (b₀): B₀= A₀× 0.017 (1) CaO amount added from anhydrous gypsum (b₁): B₁= A₁× CaO / CaSO_Four... (2) CaO amount added from silica fume (b_Two): B_Two= A_Two× 0 (3) CaO amount added from montmorillonite (b_Three): B_Three= A_Three× CaO / Montmorillonite molecular weight (4) CaO amount added from calcium carbonate (b_Four): B_Four= A_Four× CaO / CaCO_Three ... (5) CaO amount (b) added from the anionic surfactant_Five): B_Five= A_Five× 0 (6) Therefore, the target value b₁(%) Is expressed by the following formula: 100 × (b₀+ B₁+ B_Three+ B_Four) / (A₀+ A₁+ A_Two+ A_Three+ A_Four+ A_Five) ... (7)

For the Si component, the Al component, and the Mg component, the above-mentioned relational expressions are established, and by solving them,
a ₁ , a ₂ , a ₃ and a ₄ can be determined. Thus, various aggregating agents were prepared.

[0033]

[Table 1]

(2) Preparation of solidifying agent The above four types of aggregating agents and fly ash 1 as a base material
30 parts by weight of Portland cement were mixed with 00 parts by weight to obtain five types of solidifying agents. (3) Performance of each solidifying agent First, a volcanic ash clay of Ako-Kami-Ako Kitahara, Komagane-shi, Nagano was selected as a water-containing mud to be solidified. Table 2 shows the properties of the original soil.

The above-mentioned five types of solidifying agents were added to this raw earth in an amount of 5% by weight and kneaded. The mixture was dropped from a height of 30 cm with a 2.5 kg rammer into a 1000 cm ³ mold specified in JIS A1210 to form a three-layered material. After being compacted 25 times, it was covered with paraffin, cured in air for 6 days, immersed in water for 1 day, and then subjected to various tests. The results are shown in Table 2.

[0036]

[Table 2]

As is clear from Table 2, Si component, Al
Component, Ca component, and Mg component,
55% by weight, 20-30% by weight, 5-15% by weight, 5-
Sample 2, Sample 3 prepared to be in the range of 15% by weight
In each case, the plasticity index for the original soil is significantly reduced, and the uniaxial compressive strength is greatly increased, thereby exhibiting an effective solidifying action on the original soil. When Samples 2 and 3 were used, the natural water content ratio after the treatment with the original soil was significantly reduced, and it can be seen that the water absorption effect of these samples was effectively exhibited.

On the other hand, in the case of Sample 1 in which the Ca component is not in the above range, the solidification effect on the original soil shows slightly better results than the solidification agent prepared only with fly ash and cement. However, the plasticity index is high, the uniaxial compressive strength is small, and it does not function as a good soil conditioner. In the case of the sample 4 having a large amount of anhydrous gypsum, the solidification effect is certainly improved, but on the other hand, the soil after the treatment becomes too hard as a whole.

Example 2 Sludge (organic sludge) from Lake Suwa, Nagano Prefecture was selected as a water-containing mud to be solidified. Table 3 shows the properties of the original soil. The solidifying agent containing Sample 2 described above was added to the original soil, and the soil test was performed in the same manner as in Example 1 by adding the indicated ratio (% by weight). The results are shown in Table 3.

[0040]

[Table 3]

As is clear from Table 3, the solidifying agent of the present invention exerts a good solidifying action even on organic sludge, and improves sludge to a reusable state. Example 3 A volcanic ash clay having the following properties was selected as the original soil. Wet density: 1.220 g / cm ³ , dry density: 0.609 g / c
m ³ , density of soil particles: 2.528 g / cm ³ , natural water content ratio: 1
0.5%, liquid property limit: 159.5%, plasticity limit: 58.0%,
Plasticity index: 101.5, Uniaxial compressive strength: 0.316 kg / c
m ^2.

5% by weight, 7% by weight, and 10% by weight of the solidifying agent containing the above-mentioned sample 2 were added to the original soil, and a soil test was carried out in the same manner as in Example 1. Was measured. The results are shown in FIG. 1 as the relationship between the amount of the solidifying agent and the uniaxial compressive strength. For comparison, FIG. 1 also shows the results when the early-strength cement was used as the solidifying agent.

In the figure, the mark ○ indicates the case where the solidifying agent containing the sample 2 was used, and the mark ● indicates the case where the early-strength cement was used. Organic clay with the following properties was selected as the original soil. Wet density: 1.449 g / cm ³ , dry density: 0.671 g / c
m ³ , density of soil particles: 2.384 g / cm ³ , natural water content ratio: 1
15.5%, liquid limit: 120.5%, plastic limit: 67.4%,
Plasticity index: 53.1, uniaxial compressive strength: 0.212 kg / cm ² .

Into the original soil, 3%, 5%, and 7% by weight of the solidifying agent containing the above-described sample 2 was added, and a soil test was performed in the same manner as in Example 1. Was measured. The results are shown in FIG. 1 as the relationship between the amount of the solidifying agent and the uniaxial compressive strength. For comparison, FIG. 1 also shows the results when the early-strength cement was used as the solidifying agent.

In the drawing, the symbol “◇” indicates the case where the solidifying agent containing the sample 2 was used, and the symbol “◆” indicates the case where the early-strength cement was used. As is clear from FIG. 1, the solidifying action of the solidifying agent of the present invention is not limited to the case where the solidification target soil is volcanic ash clay or the case of organic clay. Is remarkably superior to the solidifying action of

[0046]

As is clear from the above description, the solidifying agent using the aggregating agent of the present invention can be used regardless of whether the target hydrous mud is inorganic or organic. Can be effectively solidified and is useful as a soil conditioner for soft ground, a solidifying agent for livestock sludge, and a solidifying agent for dredged sludge.

This is because the aggregating agent of the present invention is mainly composed of fly ash or incineration ash of papermaking sludge, which is an artificial porazone, and contains Si component and A so as to effectively promote the porazone reaction.
This is an effect brought about by adjusting the contents of the l component, the Ca component, and the Mg component. In addition, since the aggregating agent of the present invention can be prepared regardless of the target incinerated ash, it can be said that its industrial value is very large.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of a solidifying agent and the unconfined compressive strength of a modified soil.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-175397 (JP, A) JP-A-8-165467 (JP, A) JP-A-9-248598 (JP, A) 503620 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B09B 3/00 C02F 11/00-11/20 C09K 17/00

Claims (5)

(57) [Claims] 1. An incineration ash as a main component, wherein the incineration ash is uniformly mixed with a gypsum, silica fume, a natural mineral mainly composed of alumina / silicate, an alkali metal carbonate, and an anionic surfactant. made,. 20 to Si component 45 to 55% by weight in terms of SiO ₂ amount, Al component in terms of Al ₂ O ₃ amount
A granulating agent for a mud, comprising 30% by weight, 5 to 15% by weight of a Ca component in terms of CaO, and 5 to 15% by weight of a Mg component in terms of MgO. 2. The incinerated ash is fly ash or / and / or fly ash.
2. The method of claim 1, wherein the sludge is incinerated ash of paper sludge. 3. The method of claim 1, wherein the alkali metal carbonate is at least one selected from the group consisting of calcium carbonate, sodium carbonate, and magnesium carbonate. 4. The method of claim 1, wherein the natural mineral is at least one selected from the group consisting of montmorillonite, pyrophyllite, and kaolinite. 5. A solidifying agent, which is obtained by uniformly mixing 30 to 100 parts by weight of cement with 100 parts by weight of a granulating agent for a mud according to any one of claims 1 to 4.