WO2011034047A1

WO2011034047A1 - Asbestos material-treating agent and asbestos material-treating method using same

Info

Publication number: WO2011034047A1
Application number: PCT/JP2010/065810
Authority: WO
Inventors: 元樹遠山
Original assignee: 株式会社 Agua Japan
Priority date: 2009-09-15
Filing date: 2010-09-14
Publication date: 2011-03-24
Also published as: JP5122541B2; KR20110044788A; JP2011062600A; KR20130113525A; KR101340407B1

Abstract

Disclosed are a treating agent and a treating method whereby, in treating an asbestos material, safety can be improved, in particular, in carrying out the waste asbestos material to a disposal site, handling the same in the disposal site and after landfilling the same. Specifically disclosed is a treating agent for treating a waste asbestos material, which comprises an alkali metal silicate (a), a quaternary ammonium silicate (b), and water (c).

Description

Asbestos material treating agent and method of treating asbestos material using the same

This invention relates to the processing agent which processes the asbestos material used for a building etc., and the processing method of asbestos material using the same.

Asbestos (asbestos) has been widely used in buildings and the like since it has good properties such as fire resistance and heat insulation.
However, in recent years, asbestos has been found to be a cause of health problems due to suction of dust, so that asbestos material is removed and discarded on a large scale (see, for example, Patent Document 1).
And the place where it is difficult to remove the asbestos material is sealed with chemicals to prevent the asbestos from scattering.
About the removal, asbestos material is constructed by spraying etc., and removal of asbestos material is performed by peeling off from a building or the like.
The removed asbestos material is packed and landfilled at an industrial waste disposal site. Asbestos material is disposed of in a specially managed industrial waste disposal site, not a general industrial waste disposal site, because of its harmfulness.
Asbestos material processing methods include melting disposal and cement solidification disposal in addition to landfill disposal, but these are rarely used due to cost and other problems.
Regarding asbestos containment, the surface of asbestos is solidified and sealed with a predetermined medicine, or the medicine is permeated into the inside to contain and prevent scattering.

JP-A-8-28026

Asbestos materials are treated not only at the removal site, but also when the removed asbestos material is transported to an industrial waste disposal site, handled at the disposal site, and even after landfill disposal. There is a need for a more secure and safer processing method.
In addition, for the containment of asbestos, there is a need for a treatment agent that reliably suppresses the asbestos scattering and retains the incombustibility and heat insulating properties that are characteristic of asbestos itself.
The present invention has been made in view of such a situation, and in the treatment of asbestos materials, especially when transporting the removed asbestos material to a disposal site, during handling at the disposal site, and further after landfill disposal It is an object of the present invention to provide a treatment agent capable of enhancing safety, a treatment agent for safely containing asbestos, and a treatment method using the treatment agent.

The asbestos material treatment agent of the present invention contains (a) alkali metal silicate, (b) quaternary ammonium silicate, and (c) water.
In the asbestos material treatment agent of the present invention, the blending amount of the (a) alkali metal silicate with respect to the whole treatment agent is 5 to 45% by mass, and the (b) quaternary ammonium silicate has The blending amount with respect to the whole treatment agent is desirably 3 to 25% by mass.
The (a) alkali metal silicate is preferably represented by M ₂ SiO ₃ (M: alkali metal).
Further, the (b) quaternary ammonium silicate is represented by (R ₃ N) ₂ O.nSiO ₂ (R is an alkyl group having 1 or more carbon atoms, and n is an integer of 1 or more). Those are preferred.
The method for treating asbestos material according to the present invention includes: (i) a step of removing the asbestos material from the construction object;
(ii) spraying the asbestos treatment agent according to any one of claims 1 to 4 on the removed asbestos material;
(iii) packing the asbestos material sprayed with the asbestos treating agent into a disposal bag;
Is included.
In the asbestos material treatment method of the present invention, after the step (ii), before the step (iii), the step of subjecting the asbestos material sprayed with the asbestos treatment agent to compression treatment;
Can be included.

The treatment agent for asbestos material of the present invention includes (a) alkali metal silicate, (b) quaternary ammonium silicate, and (c) water, and (a) the asbestos material by the alkali metal silicate. It can be detoxified.
Asbestos material is considered to change into a harmless and stable chemical structure compound by reaction with alkali metal silicate, and the compound obtained by this reaction is unlikely to be harmful again due to environmental changes such as pH. Therefore, safety can be ensured even if the waste bag packed with waste asbestos is damaged and the waste asbestos leaks.
Moreover, (b) quaternary ammonium silicate in the asbestos material treatment agent of this invention has the effect | action which improves the permeability to the asbestos of the other component in the composition containing this. Therefore, the detoxification reaction can be promoted by deeply penetrating the components contained in the asbestos treating agent of the present invention into the asbestos material and acting on the entire asbestos material.
(B) A quaternary ammonium silicate produces | generates the calcium silicate which is a glassy substance by reaction with the calcium hydroxide contained in the building materials etc. in which the asbestos material was constructed. Therefore, the asbestos material can be fixed by this component, and the asbestos material can be reliably prevented from being released to the surrounding environment.
Further, in the asbestos treatment agent of the present invention, (c) water is used as a solvent, so that it is also superior in terms of safety of the solvent itself as compared with an organic solvent or the like. Further, (a) alkali metal silicate and (b) quaternary ammonium silicate have no problem in terms of safety because they are low in toxicity.
Accordingly, it is possible to prevent harmful asbestos from being leaked to the outside and improve safety not only at the removal work site but also at the time of transportation to the disposal site, handling at the disposal site, and after landfill disposal.

According to the method for treating asbestos material of the present invention, the asbestos material treatment agent of the present invention is used for the asbestos material removed from the construction object, so that the asbestos material is surely detoxified before packing into the disposal bag. Moreover, since it is possible to prevent the asbestos material from scattering to the outside environment after disposal, safety can be ensured.
In addition, asbestos material can be reduced in volume by compressing the asbestos material after the asbestos material treatment agent is sprayed and before packing the asbestos material into the disposal bag. Significant reductions can be made safely. Furthermore, the amount of use in the asbestos disposal site can be reduced, which is further advantageous in terms of the operational cost for disposal. In a specially managed industrial waste disposal site that requires strict leakage prevention management, the shortage of disposal space is a problem. Therefore, the technical significance of the present invention that can reduce the volume is great.

It is a figure which shows the procedure of an example of the processing method of the asbestos material of this invention. It is a schematic diagram which shows the compression apparatus which can be used for the compression process of asbestos material. It is a graph which shows the result of X-ray diffraction. Results without formic acid treatment. It is a graph which shows the result of X-ray diffraction. It is a result in the case with formic acid treatment. It is a graph which shows the result of X-ray diffraction. This is the result without formic acid treatment. It is a graph which shows the result of X-ray diffraction. It is a result in the case with formic acid treatment. It is a graph which shows the result of X-ray diffraction. This is the result without formic acid treatment. It is a graph which shows the result of X-ray diffraction. It is a result in the case with formic acid treatment. It is a graph which shows the result of X-ray diffraction. This is the result without formic acid treatment. It is a graph which shows the result of X-ray diffraction. It is a result in the case with formic acid treatment. It is a graph which shows the result of X-ray diffraction. This is the result without formic acid treatment. It is a graph which shows the result of X-ray diffraction. It is a result in the case with formic acid treatment. It is a graph which shows the result of X-ray diffraction. This is the result without formic acid treatment. It is a graph which shows the result of X-ray diffraction. It is a result in the case with formic acid treatment. It is a graph which shows the result of having performed the component analysis of the surface of asbestos material using SEM-EDX method. This is the result without formic acid treatment. It is a graph which shows the result of having performed the component analysis of the surface of asbestos material using SEM-EDX method. It is a result in the case with formic acid treatment. It is a graph which shows the result of having performed the component analysis of the surface of asbestos material using SEM-EDX method. This is the result without formic acid treatment. It is a graph which shows the result of having performed the component analysis of the surface of asbestos material using SEM-EDX method. It is a result in the case with formic acid treatment. It is a graph which shows the result of having performed the component analysis of the surface of asbestos material using SEM-EDX method. This is the result without formic acid treatment. It is a graph which shows the result of having performed the component analysis of the surface of asbestos material using SEM-EDX method. It is a result in the case with formic acid treatment. It is a graph which shows the result of having performed the component analysis of the surface of asbestos material using SEM-EDX method. It is a graph which shows the result of having performed the component analysis of the surface of asbestos material using SEM-EDX method.

The asbestos material treatment agent of the present invention (hereinafter, sometimes simply referred to as a treatment agent) is a treatment agent for treating waste asbestos material, and includes (a) an alkali metal silicate and (b) a quaternary ammonium. It contains silicate and (c) water.

The (a) alkali metal silicate used in the asbestos material treatment agent of the present invention includes M ₂ SiO ₃ , MHSi ₂ O ₅ (M: alkali metal), etc., and particularly M ₂ SiO ₃ (M: alkali metal). ) Is preferred.
Here, as an alkali metal, 1 or 2 or more is preferable among K, Na, and Li.
The blending amount of the alkali metal silicate in the asbestos treatment agent is preferably 5 to 45% by mass with respect to the entire treatment agent.
When the blending amount is less than 5% by mass, the effect of detoxifying the asbestos material is insufficient, and when it exceeds 45% by mass, the ratio of the other components is lowered, and the effect of the component is reduced, but the above range is set. By this, the effect of another component can fully be exhibited, maintaining the high detoxification effect.

The (b) quaternary ammonium silicate used in the treating agent of the present invention is (R ₃ N) ₂ O · nSiO ₂ (R is an alkyl group having 1 or more carbon atoms, and n is an integer of 1 or more. And a liquid silicate such as dimethylethanolammonium silicate, monomethyltripropanolammonium silicate, dimethyldipropanolammonium silicate, monomethyltripropanolammonium silicate, and the like.
As the quaternary ammonium silicate, one or more of these compounds can be used.
The SiO ₂ content in the quaternary ammonium silicate is preferably 15 to 40% by mass, more preferably 20 to 30% by mass.

The blending amount of (b) quaternary ammonium silicate in the treating agent is preferably 3 to 25% by mass with respect to the whole treating agent.
When the blending amount is less than 3% by mass, the effect of promoting the penetration of the alkali metal silicate is weakened, and when it exceeds 25% by mass, the ratio of the other components is reduced and the effect of the other components is reduced. By setting it as the range, the alkali metal silicate can be sufficiently permeated into the asbestos material to promote detoxification, and the effects of other components can be sufficiently exhibited.
(C) Water functions as a solvent for (a) alkali metal silicates and (b) quaternary ammonium silicates, allowing them to penetrate deep into the asbestos material.

Further, (d) a surfactant can be added to the treatment agent.
As the surfactant, nonionic, anionic, cationic, silicon or the like can be used. The surfactant has a function of enhancing the dispersibility of the alkali metal silicate and the quaternary ammonium silicate and increasing the penetration of the treatment agent into the asbestos material.
The blending amount of the surfactant is preferably 0.1 to 1% by mass with respect to the entire treating agent. By setting the amount within this range, the treating agent can be spread over a wide range of asbestos materials.

Specific examples of preferable blends include (a) alkali metal silicate 5 to 45% by mass, (b) quaternary ammonium silicate 3 to 25% by mass, and (d) surfactant 0.1 to 1% by mass. %, With the balance being (c) water.

Hereinafter, one embodiment of the processing method of asbestos material of the present invention is described.
FIG. 1 is a diagram showing the procedure of this processing method. (1) Preliminary work In the present invention, the asbestos material construction object is, for example, a building such as a concrete building or a wooden building. Specifically, for example, a boiler room, a machine room, an air conditioning machine room, a parking lot, etc. In the above, it is a casing (steel frame etc.) ceiling material, wall material and the like.
Asbestos material is formed as a coating layer on the surface of a building material (such as a steel frame) of a building by spraying or the like. Moreover, building materials (slate board etc.) containing asbestos material may be used for a building.
Asbestos is often used with cement-based materials such as concrete and mortar. Cementitious materials typically include calcium oxide (CaO) and silicon dioxide (SiO ₂ ). A part of CaO becomes Ca (OH) ₂ by reaction with water. In addition to these, cementitious materials often contain aluminum oxide (Al ₂ O ₃ ) and ferric oxide (Fe ₂ O ₃ ).

As shown in FIG. 1, prior to removal of asbestos material, it is preferable to take measures to prevent external leakage of asbestos material as follows.
After cleaning the removal work site, in order to prevent the asbestos material from adhering, it is cured by covering the floor, wall surface, etc. of the part where the asbestos material is not constructed with a sheet or the like.
A security zone with the removal work site as a closed space will be installed, and a negative pressure dust remover will be installed to make this security zone negative.

(2) Asbestos material removal work The asbestos material constructed on the construction object is removed by scraping it with an appropriate tool. Hereinafter, the removed asbestos material may be referred to as waste asbestos material.
At this time, scattering of the asbestos material can be suppressed by spraying a scattering inhibitor made of metal silicate or the like on the asbestos material. The asbestos dust scattered in the air is purified by a negative pressure dust remover and discarded to the outside.
The operator preferably wears protective clothing to prevent asbestos exposure.

(3) Processing agent spraying operation The above-mentioned processing agent is sprayed on waste asbestos material. As a spraying method, spraying may be employed, or a method of applying using an applicator such as a brush may be employed.
The application amount of the treatment agent is preferably 30 to 70 parts by mass with respect to 100 parts by mass of the asbestos material. A high detoxifying effect can be obtained by setting the spraying amount within this range. In addition, the spreading amount of the treatment agent can be set outside the above range depending on the type and components of the asbestos material.

The (a) alkali metal silicate contained in the treatment agent reacts with the asbestos material to render it harmless.
(A) The reaction between the alkali metal silicate and the asbestos material is not clear in detail, but the following estimation is possible.
For example, an asbestos material having a structure represented by the formula (1) reacts with (a) an alkali metal silicate (potassium silicate: K ₂ SiO ₃ ) under a strong base condition (for example, pH 10 or more), whereby the formula It is conceivable that the reaction has the structure shown in (2) and the decomposition products shown in formulas (3) to (5).
In order to obtain strong base conditions, the reaction may be carried out in the presence of a strong base compound such as KOH, Ca (OH) ₂ , NaOH or the like. In this example, KOH is used.

In the above reaction, a part of magnesium is eliminated as a product represented by the formulas (3) to (5) by reaction with KOH.
Further, as shown in the formula (6), magnesium that is chelate-bonded to a pair of silanol groups (Si—OH) in the asbestos material is separated from one silanol group and is bonded to potassium silicate, and the magnesium is separated. Potassium is ionically bonded to the silanol group.
The structure in which potassium silicate is bonded to the silanol group is considered to be chemically stable, and the reverse reaction of formula (6) hardly occurs even when the pH is lowered.

Thus, the asbestos material is rendered harmless by the elimination reaction of magnesium and the binding reaction with potassium silicate.
As described above, since the reverse reaction is unlikely to occur with respect to the reaction of the formula (6), the asbestos material is not easily detoxified.
The use of the treatment agent of the present invention makes it possible for the asbestos material to be in a form in which re-poisoning is unlikely to occur due to a change in pH.

In contrast, (a) without using an alkali metal silicate, the asbestos material represented by the formula (1) is simply put under strong base conditions (for example, KOH is added) as shown in the formula (7). However, when the pH is lowered, the reverse reaction easily occurs and the structure shown in Formula (1) is restored by hydrolysis.

(B) Quaternary ammonium silicate has the effect of increasing the permeability (wetability) to asbestos material. For this reason, the other component in a processing agent can osmose | permeate deeply inside the asbestos material, and can be spread over the whole. Therefore, (a) alkali metal silicate can act on the whole asbestos material, and the said detoxification reaction can be accelerated | stimulated.

When calcium hydroxide (Ca (OH) ₂ ) is present, the quaternary ammonium silicate reacts with this to produce calcium silicate which is a glassy substance.
When asbestos is used together with cement-based materials (concrete, mortar, etc.), asbestos reacts with calcium hydroxide contained in the cement-based material to produce glassy calcium silicate. Therefore, the asbestos material can be fixed.
Formula (8) is an example of the formation reaction of calcium silicate.

Since quaternary ammonium silicate produces calcium silicate, which is a glassy substance, and asbestos material is fixed, even if the detoxification reaction by alkali metal silicate becomes insufficient, harmful asbestos The material can be prevented from being released due to scattering or the like.

Table 1 shows the experimental results showing the solidification action by the quaternary ammonium silicate.
In Example 1, a 17.4 mass% aqueous solution of quaternary ammonium silicate was applied to a test specimen made of concrete using a brush (average coating amount 0.14 g / cm ² ). It was measured. For comparison, the results of Example 2 in which no quaternary ammonium silicate aqueous solution is applied are also shown.
The compressive strength was measured according to JIS A1108. The Schmidt hammer strength was measured according to JSCE-G504. The micro Vickers hardness was measured using a micro Vickers hardness meter (scratch tester).

As shown in Table 1, since the mechanical strength in Example 1 was higher than that in Example 2, the solidification action by the quaternary ammonium silicate was confirmed.

(4) Asbestos material collection and compression work The asbestos material sprayed with the treatment agent can be put into a disposal bag and compressed using a compression device.
FIG. 2 shows an example of the compression device. In order to compress the asbestos material 1 using this apparatus, the asbestos material 1 put in the disposal bag 2 is compressed by the pressing body 4 in the compression container 3.
Thereby, volume reduction of the asbestos material 1 can be achieved. The volume of the asbestos material 1 can be, for example, about 1/3 to 1/4 of that before compression.
For this reason, transportation and disposal costs can be greatly reduced. Furthermore, the amount of treatment agent used can be reduced, which is further advantageous in terms of cost.
In particular, in a specially managed industrial waste disposal site that requires strict leakage prevention management, the shortage of disposal space is a problem. Therefore, the technical significance of this method capable of volume reduction is great.

Since the volume is reduced, the treatment agent can be spread over the entire asbestos material 1 and the detoxification reaction with the alkali metal silicate can be surely advanced. Also, immobilization by the production of calcium silicate can be promoted. The compression treatment also has the effect of preventing the asbestos material from scattering.

Moreover, since the capacity of the asbestos material 1 becomes small, the asbestos material 1 can be additionally charged into the disposal bag 2 and recompressed. Thereby, since many asbestos materials 1 can be stuffed in one disposal bag 2, the number of bagging asbestos materials (packing asbestos materials) which need to be disposed can be reduced, and transportation and disposal costs can be further reduced.
The protective clothing and curing sheets used in the asbestos material removing operation can be put into the disposal bag 2 and compressed.
In order to reliably prevent external leakage of the asbestos material 1, a plurality of disposal bags 2 are used. Specifically, it is packed in a double bag. By using the disposal bag 2, it is possible to prevent the asbestos material from scattering. Three or more disposal bags 2 may be used.

(5) Carrying out to disposal site After sealing the opening of the disposal bag 2, this bagging asbestos material (packing asbestos material) is carried out from the work site and transported to a specially managed industrial waste disposal site. Bagged asbestos materials are disposed of in landfills at the industrial waste disposal site.

Since the treatment agent of the present invention contains (a) alkali metal silicate and (b) quaternary ammonium silicate, (a) the asbestos material can be rendered harmless by the alkali metal silicate. .
Asbestos material is thought to change to a harmless and stable chemical structure by reaction with alkali metal silicate, and this compound is unlikely to be harmed again due to environmental changes such as pH, so if a disposal bag for packing is used. Even if it is damaged and waste asbestos material leaks, safety can be secured.
In addition, (b) quaternary ammonium silicate has the effect of increasing the permeability, so that the treatment agent is deeply penetrated into the asbestos material, and the alkali metal silicate is allowed to act on the whole of the asbestos material. The chemical reaction can be promoted.
Furthermore, (b) quaternary ammonium silicate produces calcium silicate which is a glassy substance by reaction with calcium hydroxide contained in building materials and the like on which asbestos materials are constructed. By fixing the asbestos material by being consolidated or the like, it is possible to reliably prevent the asbestos material from being released to the outside.
In addition, since (c) water is used as a solvent, the solvent itself is also superior in terms of safety compared to an organic solvent or the like. Further, (a) alkali metal silicate and (b) quaternary ammonium silicate have no problem in terms of safety because they are low in toxicity.
Accordingly, it is possible to prevent harmful asbestos from being leaked to the outside and improve safety not only at the removal work site but also at the time of transportation to the disposal site, handling at the disposal site, and after landfill disposal.

According to the asbestos material processing method of the present invention, since the above-mentioned treatment agent is used, the asbestos material can be reliably rendered harmless and safety can be ensured.
Furthermore, asbestos material can be reduced in volume by compressing the asbestos material, so that transportation and disposal costs can be greatly reduced. Furthermore, the amount of treatment agent used can be reduced, which is further advantageous in terms of cost.
In particular, in a specially managed industrial waste disposal site that requires strict leakage prevention management, the shortage of disposal space is a problem. Therefore, the technical significance of this method capable of volume reduction is great.

Hereafter, the effect of this invention is shown by a specific example.
Asbestos was quantified as follows. For asbestos material (standard sample) and internal standard substance (talc: Mg ₃ Si ₄ O ₁₀ (OH) ₂ ) mixed in known amounts, the diffraction line intensity ratio between asbestos material (standard sample) and internal standard substance A calibration curve was prepared by measurement with an X-ray diffractometer. Asbestos material (standard sample) is a 95% chrysotile standard sample provided by the Japan Working Environment Measurement Association.
A known amount of the internal standard substance was added to the sample to be measured, and the diffraction line intensity ratio between the sample to be measured and the internal standard substance was determined with an X-ray diffractometer. The asbestos material mass ratio was determined from the diffraction line intensity ratio using the calibration curve, and the asbestos material content was calculated from the value.

(Test Example 1) (Blank test)
Asbestos material (standard sample) was subjected to component analysis by the X-ray diffraction method.
For comparison, a similar test was conducted except that the asbestos material was treated with formic acid.
The formic acid treatment is a treatment in which 20% by mass aqueous formic acid solution is added to asbestos and dried. The results are shown in Table 2.
3A and 3B are graphs showing the results of X-ray diffraction. The horizontal axis is the X-ray incident angle, and the vertical axis is the X-ray intensity. FIG. 3A shows the results without formic acid treatment, and FIG. 3B shows the results with formic acid treatment. P1 and P2 are peaks indicating asbestos material (standard sample), and P3 and P4 are peaks indicating internal standard substance (talc).

(Test Example 2) (Calcium hydroxide only treatment)
9.0 g of a 20% by mass calcium hydroxide (Ca (OH) ₂ ) aqueous solution was added to and mixed with 0.6 g of asbestos material (standard sample).
After drying at 40 ° C. for 1 week, the asbestos material was subjected to component analysis by X-ray diffraction method to calculate the asbestos content.
The asbestos content is the ratio (mass%) of the asbestos amount obtained in this test example to the asbestos amount in test example 1 (blank test).
For comparison, a similar test was performed on the dried asbestos material, except that formic acid treatment was performed prior to component analysis. The results are shown in Table 2.
FIG. 4A is a graph showing the results of X-ray diffraction without formic acid treatment, and FIG. 4B is a graph showing the results of X-ray diffraction with formic acid treatment.

(Test Example 3) (Cement water only treatment)
7.5 g of cement water was added to and mixed with 0.6 g of asbestos material (standard sample).
Cement water is obtained by suspending Portland cement in water (cement: water = 1: 3 (mass basis)).
After drying at 40 ° C. for 1 week, the asbestos material was subjected to component analysis by X-ray diffraction method to calculate the asbestos content.
For comparison, a similar test was performed on the dried asbestos material, except that formic acid treatment was performed prior to component analysis. The results are shown in Table 2.
FIG. 5A is a graph showing the results of X-ray diffraction without formic acid treatment, and FIG. 5B is a graph showing the results of X-ray diffraction with formic acid treatment.

(Test Example 4) (Treatment agent only treatment)
To 0.6 g of asbestos material (standard sample), 3 ml of the treatment agent was added and mixed, and dried at 40 ° C. for 24 hours.
The compounding of the processing agent was (a) alkali metal silicate (potassium silicate: K ₂ SiO ₃ ) 9.3 mass%, (b) quaternary ammonium silicate (dimethylethanolammonium silicate) 10.6 mass %, (D) 0.5% by mass of surfactant, and (c) 79.6% by mass of water.
A nonionic surfactant was used as the surfactant.
The asbestos material was mixed again with 3 ml of the treatment agent, dried at 40 ° C. for 24 hours, then mixed with 3 ml of the treatment agent three times, and dried at 40 ° C. for 24 hours.
About this asbestos material, the component analysis was performed by the X ray diffraction method, and the asbestos content rate was computed.
For comparison, a similar test was performed on the dried asbestos material, except that formic acid treatment was performed prior to component analysis. The results are shown in Table 2.
FIG. 6A is a graph showing the results of X-ray diffraction without formic acid treatment, and FIG. 6B is a graph showing the results of X-ray diffraction with formic acid treatment.

(Test Example 5) (Treatment agent + calcium hydroxide treatment)
To 0.6 g of asbestos material (standard sample), 3 ml of the same treatment agent as in Test Example 4 was added and mixed, and dried at 40 ° C. for 24 hours.
To this asbestos material, 9.0 g of a 20% by mass calcium hydroxide (Ca (OH) ₂ ) aqueous solution was added and mixed, dried at 40 ° C. for 1 week, then added again with 3 ml of the treatment agent, and mixed at 40 ° C. After drying for 24 hours, 3 ml of the treatment agent was added and mixed three times and dried at 40 ° C. for 24 hours.
About this asbestos material, the component analysis was performed by the X ray diffraction method, and the asbestos content rate was computed.
For comparison, a similar test was performed on the dried asbestos material, except that formic acid treatment was performed prior to component analysis. The results are shown in Table 2.
FIG. 7A is a graph showing the results of X-ray diffraction without formic acid treatment, and FIG. 7B is a graph showing the results of X-ray diffraction with formic acid treatment.

(Test Example 6) (Treatment agent + cement water treatment)
To 0.6 g of asbestos material (standard sample), 3 ml of the same treatment agent as in Test Example 4 was added and mixed, and dried at 40 ° C. for 24 hours.
After adding 7.5 g of cement water similar to Test Example 3 to this asbestos material and mixing, drying at 40 ° C. for 1 week, adding 3 ml of treatment agent again, mixing and drying at 40 ° C. for 24 hours. Three times, 3 ml of the treatment agent was added and mixed, and dried at 40 ° C. for 24 hours.
About this asbestos material, the component analysis was performed by the X ray diffraction method, and the asbestos content rate was computed.
For comparison, a similar test was performed on the dried asbestos material, except that formic acid treatment was performed prior to component analysis. The results are shown in Table 2.
FIG. 8A is a graph showing the results of X-ray diffraction without formic acid treatment, and FIG. 8B is a graph showing the results of X-ray diffraction with formic acid treatment.

As shown in Table 2, from Test Examples 2 and 3, when the asbestos material was treated with calcium hydroxide or cement water, the asbestos content decreased, but when the pH was lowered by formic acid treatment, the asbestos content was reduced. It can be seen that returns to 100% or close to it.
On the other hand, as shown in Test Examples 4 to 6, when the treatment agent was used, the asbestos content was low, and this content was not greatly increased by the formic acid treatment.
From this, it can be seen that by using the treatment agent of the present invention, a part of asbestos was rendered harmless and re-toxification was unlikely to occur even when the pH environment changed.
This can be attributed to the irreversible change of the chemical structure of asbestos to a harmless structure due to the reaction with the treating agent of the present invention.
Moreover, in the presence of calcium hydroxide or cement water, the asbestos content was lower.

9A and 9B show the results of component analysis of the surface of the asbestos material (standard sample) used in Test Example 1 using a scanning electron microscope-energy dispersive X-ray analysis method (SEM-EDX method). The vertical axis represents the content (% by mass). FIG. 9A shows the results without formic acid treatment, and FIG. 9B shows the results with formic acid treatment. From these, it can be seen that almost no change in the composition of the asbestos material due to the formic acid treatment occurs.

10A and 10B are component analysis results of the asbestos material processed in Test Example 2 by the SEM-EDX method. FIG. 10A shows the results without formic acid treatment, and FIG. 10B shows the results with formic acid treatment.
11A and 11B show the component analysis results of the asbestos material processed in Test Example 3 by the SEM-EDX method. FIG. 11A shows the results without formic acid treatment, and FIG. 11B shows the results with formic acid treatment.
From these, it can be seen that when the asbestos material is treated with calcium hydroxide or cement water, the magnesium content decreases, but it returns to 100% or a value close to it by formic acid treatment (pH reduction).

FIG. 12 shows the result of component analysis of the asbestos material treated in Test Example 5 (with formic acid treatment) by the SEM-EDX method, and FIG. 13 shows the components of the asbestos material treated in Test Example 6 (with formic acid treatment). It is an analysis result.
From these results, it was confirmed that the magnesium content did not increase even when formic acid treatment (pH reduction) was performed by using a treatment agent, and recombination of detached magnesium was less likely to occur.

(Test Examples 7 to 12)
An aqueous solution of a quaternary ammonium silicate (2.5% by mass in terms of solid content) was applied to the surface of a test body made of the material shown in Table 3 and dried. The contact angle of water on this surface was measured.

As shown in Table 3, the contact angle was greatly reduced by the quaternary ammonium silicate.
From this, it can be seen that the quaternary ammonium silicate has an effect of increasing the permeability (wetting property).

(Test Examples 13 to 15)
A treatment agent similar to that used in Test Example 4 was sprayed on 300 g of asbestos material (bulk specific gravity: about 0.1 to 0.2 g / cm ³ ). The amount of treatment agent used was 100 g (Test Example 13), 150 g (Test Example 14), or 200 g (Test Example 15). The asbestos material was compression-processed using the compression apparatus shown in FIG. The compression rate was about 70-80%.

In any of Test Examples 13 to 15, asbestos material solidified by the compression treatment was obtained.
In particular, in Test Example 14, the solidified asbestos material collapses only slightly even when a strong pressure is applied from the outside. In Test Example 15, the solidified asbestos material is applied with a strong pressure from the outside. However, the shape did not collapse so that it was easy to handle during transportation.

(Test Example 16)
The asbestos material treated in the same manner as in Test Example 6 was immersed in water having a pH of 7.8 to 8.3, and the elution amount of heavy metals and the like was measured. The measurement method complies with the “Ministerial Ordinance (Ministry of Internal Affairs and Communications Ordinance No. 5) that establishes the criteria for judging industrial waste including metals. The results are shown in Table 4.

From Table 4, it can be seen that the asbestos material treated according to the present invention hardly elutions heavy metals or the like in any of the detection items and satisfies the regulation value.

According to the present invention, asbestos material can be rendered harmless in a form that is unlikely to be re-harmful due to environmental changes, so that it can be used not only at the removal work site, but also during transportation to the disposal site, handling at the disposal site, and after landfill disposal. Prevents harmful asbestos from leaking outside and improves safety.

DESCRIPTION OF SYMBOLS 1 ... Asbestos material, 2 ... Waste bag, 3 ... Compression container, 4 ... Pressing body.

Claims

(A) alkali metal silicate,
An asbestos treatment agent comprising (b) quaternary ammonium silicate and (c) water.
The blending amount of (a) alkali metal silicate with respect to the entire treating agent is 5 to 45% by mass, and the blending amount of (b) quaternary ammonium silicate with respect to the entire treating agent is 3 to The asbestos-material processing agent of Claim 1 which is 25 mass%.
Wherein (a) an alkali metal silicate, M 2 SiO 3: a (M an alkali metal), asbestos material processing agent according to claim 1 or 2.
The (b) quaternary ammonium silicate is (R 3 N) 2 O.nSiO 2 (R is an alkyl group having 1 or more carbon atoms, and n is an integer of 1 or more). The asbestos material treatment agent according to any one of 1 to 3.
(i) a step of spraying the asbestos material treatment agent according to any one of claims 1 to 4 to the asbestos material removed from the construction object;
(ii) packing the asbestos material sprayed with the asbestos treatment agent into a disposal bag;
A method of treating asbestos material, comprising:
After the step (i) and before the step (ii), subjecting the asbestos material sprayed with the asbestos treatment agent to compression treatment;
The method of processing the asbestos material of Claim 5 containing this.