JP2015196782A - Asbestos decomposition treatment agent and method for making asbestos harmless - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide various problems indicated heretofore in an asbestos treatment method, and to make asbestos included in the edge materials of building materials or the like harmless efficiently in a short time.SOLUTION: This invention is used for decomposing asbestos and efficiently modifying the same from a fibrous shape into a lumpy shape in a short time. Provided is a treatment method for decomposing asbestos where a decomposition treatment agent for asbestos essentially consisting of a polysulfide aqueous solution in which alkali metal and sulfur are ionically bonded and asbestos-containing building materials is immersed or coated with the material to be treated containing asbestos, and heating is performed at high temperature, the asbestos contained in the object to be treated is efficiently decomposed in a short time.

Description

Until now, various problems have been pointed out in the asbestos treatment method. The present invention relates to a method for efficiently detoxifying asbestos contained in end materials such as building materials in a short time.

  Asbestos is used in a wide range of applications as a construction material because it is excellent in durability, heat resistance, chemical resistance, electrical insulation, and other properties and is inexpensive. However, if the fiber that is frequently used as construction material is scattered and sucked into the human body, there is a risk of harming health, so measures to prohibit its use are taken, and waste materials that have already been used as construction material. Processing has been taken.

Until now, in order to detoxify harmful asbestos (asbestos), heating asbestos-containing products has been performed. That is, by heating the asbestos-containing sample to a temperature of 850 ° C. or higher, the asbestos of the needle-like crystals is modified and decomposed to make it harmless. In heating an asbestos-containing product, dielectric heating by high frequency by microwave irradiation is used.

  In Unexamined-Japanese-Patent No. 2010-149080 (patent document 1), when performing the detoxification process of asbestos by heating an asbestos containing material using a microwave, the state which made the asbestos containing material hold | maintain at a holder Asbestos detoxification treatment method capable of detoxifying asbestos with high efficiency even if it is treated with the above. Specifically, the asbestos-containing material is detoxified by supplying the asbestos-containing material into a heating furnace and heating it. As this heating furnace, the heating furnace heated by irradiating an asbestos containing material with a microwave is used. The asbestos-containing material is supplied into the heating furnace in a state where the asbestos-containing material is held in a holder whose temperature rising rate to the asbestos denaturation temperature is equal to or higher than that of the asbestos-containing material. Thereby, the heating efficiency of asbestos is improved.

  Moreover, in JP 2010-167332 A (Patent Document 2), asbestos that can modify asbestos contained by heating the cement hardened body in a short time while preventing the cement hardened body from exploding. A detoxification method is provided. Asbestos contained in the hardened cement is modified by heating the hardened cement using both the external heating means for heating the hardened cement from the outside and the internal heating means for heating the hardened cement from the inside. Detoxify. And the 1st heating process which heats to disperse the crystal water in a hardened cement body, the 2nd heating process which heats so that the temperature inside a hardened cement body may be raised to the surface temperature, The hardened cement body is heat-treated stepwise by a third heating step in which heating is performed at a temperature that denatures asbestos.

  However, the method of processing asbestos-containing products by microwave irradiation requires a large facility and is an expensive process. Furthermore, during processing, asbestos was scattered in the environment, and there was a risk of causing harm to workers. Moreover, in the method using a cement hardening body, it was necessary to use high temperature of 850 degreeC or more.

JP 2010-149080 A JP 2010-167332 A

  In Patent Document 1, asbestos can be detoxified with high efficiency even when it is treated in a state where the asbestos-containing material is held in a holder when performing asbestos detoxification treatment using microwaves. Although a detoxification treatment method is provided, the use of microwaves remains unchanged. Moreover, in patent document 2, by heating an cement hardening body together using the external heating means which heats a cement hardening body from the outside, and an internal heating means which heats a cement hardening body from the inside, In the detoxification treatment by modifying the asbestos contained in the first heating step of heating to disperse free water and crystal water in the hardened cement body, the temperature inside the hardened cement body is close to the surface temperature Of the asbestos, wherein the hardened cement body is heat-treated stepwise by a second heating step of heating so as to increase the temperature and a third heating step of heating at a temperature to denature the asbestos in the hardened cement body. Although it is a detoxification treatment method, in the first heating step, the temperature of the cement hardened body is increased to 650 to 750 ° C., and in the second heating step, In the third heating step, the temperature of the cement cured body is maintained at 850 ° C. or higher, and a high temperature of 850 ° C. or higher is required. .

Here, the present invention has been made in the background of such circumstances, and the problem to be solved is related to the decomposition and detoxification of asbestos, and in particular, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra) An object of the present invention is to provide a decomposition treatment agent for asbestos mainly composed of one or a mixture thereof and a polysulfide aqueous solution in which sulfur is ion-bonded. In this decomposition method, asbestos is decomposed to efficiently modify the fiber form into a block form in a short time.

  In the present invention, in order to solve such problems, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra), or a mixture thereof, and a polysulfide aqueous solution in which sulfur is ion-bonded. An asbestos decomposition treatment agent characterized in that the asbestos decomposition treatment agent according to the present invention is used as a gist thereof, and asbestos in an asbestos-containing building material is used as an object to be decomposed. It will be.

And in order to make the asbestos decomposition processing agent according to this invention act advantageously, after impregnating asbestos and an asbestos-containing building material in the asbestos decomposition processing agent, by combining heating or heating and an oxidizing agent together The gist is also a method of detoxifying asbestos characterized by promoting decomposition.

In addition, according to one of the preferable embodiments of the asbestos decomposition treatment agent according to the present invention, asbestos and asbestos-containing building materials are immersed in the asbestos decomposition treatment agent, and a temperature of 100 ° C. to 250 ° C. in the reaction aqueous solution. It is characterized by reacting for 3 to 18 hours under conditions.

  Moreover, according to one of the preferable aspects of the asbestos decomposition processing method according to this invention, asbestos and asbestos-containing building materials are shape | molded and granulated to a suitable magnitude | size by the crushing process process of asbestos and asbestos-containing building materials. It features a pre-treatment that prevents scattering and improves handling operation performance.

  And according to the desirable aspect of the asbestos decomposition treatment method according to the present invention, the sulfur-based decomposition residue in the exhaust gas generated in the heating treatment process for detoxifying asbestos and asbestos-containing building materials is removed. The gist is also a method for detoxifying the characteristic asbestos.

In the invention according to claim 1, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium ( A decomposition treatment agent for asbestos comprising, as a main component, a polysulfide aqueous solution in which any one of Ca), strontium (Sr), barium (Ba), radium (Ra) or a mixture thereof and sulfur is ion-bonded is provided. The asbestos is intended to decompose asbestos in the asbestos-containing building material, but is not limited thereto.

In the invention which concerns on Claim 3, after impregnating asbestos and an asbestos containing building material in the above-mentioned decomposition agent of asbestos, decomposition | disassembly is accelerated | stimulated by using a heating or a combination of heating and an oxidizing agent, It is characterized by the above-mentioned. It provides a method for detoxifying asbestos.

Moreover, in the invention which concerns on Claim 4, asbestos and an asbestos containing building material are immersed in the above-mentioned decomposition agent of asbestos, and it is made to react for 3 to 18 hours under the temperature conditions of 100 to 250 degreeC in the reaction aqueous solution. The present invention provides a method for detoxifying asbestos characterized by the above.

Further, in the invention according to claim 5, after asbestos and asbestos-containing building material are immersed in the above-described decomposition agent for asbestos, the temperature is set to 400 in a high temperature furnace using fine powder of an oxidizer and an organic binder. The present invention provides a method for detoxifying asbestos, characterized by self-combustion at ˜900 ° C. for 30 to 120 minutes and high-speed oxidation treatment.

Further, in the invention according to claim 6, the asbestos and the asbestos-containing building material are appropriately sized in the crushing treatment process of asbestos and the asbestos-containing building material before or after the asbestos and the asbestos-containing building material are immersed in the decomposition treatment agent. Furthermore, the present invention provides a method for detoxifying asbestos characterized by pretreatment for preventing scattering and handling operation performance by molding or granulating.

In this invention, there exists an effect described below.

That is, in the present invention, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca) Asbestos is decomposed by the action of asbestos mainly composed of a polysulfide aqueous solution in which sulfur is ionically bonded to any one of strontium (Sr), barium (Ba), and radium (Ra) and a mixture thereof. It can be decomposed and modified from a fibrous form to a massive form.

Photograph of impregnating asbestos-containing building materials in an asbestos decomposition treatment agent containing polysulfide aqueous solution as the main component X-ray diffraction measurement result measured after grinding asbestos-containing building materials with a ball mill X-ray diffraction measurement results measured after impregnating asbestos-containing building materials into an asbestos decomposition treatment agent containing polysulfide aqueous solution as the main component and grinding with a ball mill

The asbestos decomposition treatment agent according to the present invention is mainly composed of a polysulfide aqueous solution in which sulfur is ion-bonded with any one of a group 1 or group 2 metal body or a mixture thereof. The asbestos decomposition treatment agent according to the present invention may be added with an aqueous solution of metal hydroxide or an aqueous solution containing metal hydroxide fine particles.

Here, the Group 1 metal body refers to any one of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). The metal body refers to any one of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). The polysulfide aqueous solution is lithium sulfide (Li ₂ S _X ), sodium sulfide (Na ₂ S _X ), potassium sulfide (K ₂ S _X ), rubidium sulfide (Rb ₂ S _X ), cesium sulfide (Cs ₂ S _X ), francium sulfide (Fr ₂ S _X ), sulfide An aqueous solution of S _X = 2-12 of beryllium (BeS _X ), magnesium sulfide (MgS _X ), calcium sulfide (CaS _X ), strontium sulfide (SrS _X ), barium sulfide (BaS _X ), and radium sulfide (RaS _X ) Pointing, metal hydroxide It is lithium hydroxide (Li ₂ OH), sodium hydroxide (Na ₂ OH), potassium hydroxide (K ₂ OH), rubidium hydroxide (Rb ₂ OH), cesium hydroxide (Cs ₂ OH), hydroxide francium (Fr ₂ OH), beryllium hydroxide (BeOH), magnesium hydroxide (MgOH), calcium hydroxide (CaOH), strontium hydroxide (SrOH), barium hydroxide (BaOH), radium hydroxide (RaOH).

Lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), Any one of barium (Ba) and radium (Ra) or a mixture thereof and a polysulfide aqueous solution (S _X ( _X = 2 to 12)) in which sulfur is ion-bonded are generated using a known chemical reaction. be able to.

In particular, as a method for stably and safely producing polysulfide (however, S _X ( _X = 6 to 12)), any one of potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide, or these There is a method in which a mixture and sulfur are reacted by stirring and mixing under high pressure of 98 ° C. to 345 ° C. without discharging steam in a sealed container.

For example, when calcium hydroxide and sulfur are used, they can be produced by mixing slaked lime, sulfur and water.
^{_{Ca (OH) 2 → Ca 2+}} + 2OH -
Ca ²⁺ ＋ S → CaS
Reaction occurs.
This CaS is
_{^{2CaS + 4OH - → H 2 S}} + Ca (OH) 2 + O 2 + S 2+ 2Ca 2+
It becomes. Other metals also cause upset reactions, where S ^2- has an important role in asbestos degradation.

Here, in the conventional manufacturing method, a part of hydrogen sulfide and oxygen was released to the atmosphere as steam, but in the present invention, this reaction is performed in a sealed container so that the steam is not discharged. .

Therefore, the above reaction proceeds accurately,
H ₂ S + Ca (OH) ₂ + CaS → Ca (HS) ₂ + Ca (OH) ₂
It becomes.

CaS is
2CaS + 2H ₂ O → Ca (HS) ₂ + Ca (OH) ₂
It becomes.

In addition, CaS
CaS + ( _X -1) S → CaS _X
Thus, CaS _X ( _X = 6) is stably generated.

This is not limited to the case where calcium hydroxide is used. Even when potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide or a mixture thereof is used, S _X ( _X = 6) is _reduced. The processing agent contained can be generated stably. In particular, potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide, or a mixture thereof and sulfur and potassium, magnesium, calcium, or sodium adhering to the surface of the sulfur particles are crushed and peeled off. By reacting while stirring and mixing, a treatment agent mainly composed of polysulfide (however, S _X ( _X = 6)) can be generated more stably.

In addition, when the reaction is performed at a temperature higher than the melting temperature of sulfur, a treatment agent mainly composed of polysulfide (however, S _X ( _X = 8)) can be stably generated. In addition, when a predetermined amount of potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide or a mixture thereof is continuously mixed in a mixed solution of sulfur and hot water, polysulfide However, it is possible to stably produce a treating agent having S _X ( _X = 8 to 10) as a main component.

Moreover, slaked lime is mixed in a mixed solution of potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide or a mixture thereof and sulfur and hot water in a low temperature environment (−20 ° C. to 0 ° C.). In this case, it is possible to stably produce a milk-like treatment agent containing polysulfide (however, S _X ( _X = 6 to 12)) as a main component and capable of solidifying the object to be treated.

In addition, calcium is mixed in a mixed solution of potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide or a mixture thereof and sulfur and hot water in a low temperature environment (-30 ° C to -25 ° C). In this case, it is possible to stably produce a treating agent mainly composed of polysulfide (however, S _X ( _X = 8)).

When sulfur previously ground to 100 μm or less (preferably 50 μm or less), potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide or a mixture thereof is used in a powder or silt state Can stably produce a treatment agent mainly composed of polysulfide (however, S _X ( _X = 10 to 12)).

In addition, the decomposition treatment agent can be generated using alkaline ash, which is waste, as a raw material. For example, fly ash (coal species: generated by co-firing 50% Musselburg and 50% Drayton, alkalinity pH 13.5) is used as alkali ash, fly ash 20 parts by weight, sulfur 20 parts by weight, water 100 weights First, 20 parts by weight of fly ash and 100 parts by weight of water are put in a reaction can, the upper lid is closed, and the mixer is operated to mix for about 10 minutes.

Next, a safety valve is set, the exhaust pressure is set to about 10 kg / cm ² as the upper limit reaction pressure, the furnace body cooling drain valve and the cooling valve are opened, and the cooling water inlet valve is opened to allow water to flow.

Next, in order to suppress evaporation during the reaction, a preload of about 2.5 kg / cm ² is applied by pressurization with an air compressor.

Next, the burner is ignited, the pressure gauge and the thermometer are confirmed, and the temperature is raised while mixing. At this time, the pressure is set to 10 kg / cm ² or less, and after the thermometer display reaches 110 ° C., the mixture is reacted for about 30 minutes.

Next, the burner is stopped and left until the pressure gauge is lowered. When the pressure gauge is stabilized, the final residual pressure is completely discharged by the exhaust valve and assimilated with the atmospheric pressure. At this time, since toxic gas containing hydrogen sulfide is discharged, it is necessary to appropriately treat it by a conventionally used method.

Next, the mixer is stopped, the discharge valve is opened, the precipitate and liquid are discharged, and these are collected.

Next, the recovered product is cooled and separated by precipitation to obtain a chemical solution and a precipitate. Here, 130 parts by weight of the chemical solution and 20 parts by weight of the precipitate were obtained.

Further, the collected chemical solution contained calcium polysulfide and was a yellow-green pH 10 liquid with a liquid specific gravity of 1.2 g / mL.

Moreover, as a raw material of an above-mentioned decomposition processing agent, it may replace with alkaline ash and what was adjusted to pH13.5 with cellulose-based incinerator fly ash, such as paper, and a base may be used. In this case, a brown pH 11 liquid containing calcium polysulfide and having a liquid specific gravity of 1.15 g / mL was obtained.

The liquid thus produced, and further the aqueous precipitate solution can be used as an asbestos decomposition treatment agent.

  Hereinafter, test examples of the present invention will be shown and the present invention will be clarified more specifically. However, the present invention is not subject to any restrictions by the description of such test examples. Needless to say. In addition to the following test examples, the present invention includes various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the specific description described above. It should be understood that improvements and the like can be added.

First, an aqueous solution (concentration: 25% by weight) of an asbestos decomposition treatment agent containing a polysulfide aqueous solution as a main component was prepared. The color vest piece which is an asbestos containing building material was immersed in the aqueous solution of this decomposition processing agent (FIG. 1). In FIG. 1, reference numeral 1 denotes an immersion experiment container, which is a 50 mL small beaker-like container. 2 is an aqueous solution of a decomposition treatment agent, 3 is a color vest piece containing asbestos, and a lump of 30 mm in length, 20 mm in width, and 10 mm in height was used. 4 is a sealed rubber, which is 60 minutes after immersion, in which the air inside the color vest piece was released in the form of bubbles and accumulated in the upper part of the experimental container, but disappeared after 300 minutes. The volume of the aqueous solution of the decomposition treatment agent was adjusted to 4% with respect to the weight of the asbestos-containing material (color vest piece). If the weight percent is 4% or more, the asbestos-containing material can be made harmless efficiently. Therefore, 4% by weight was the optimum value. The volume ratio of color vest to aqueous solution was about 1: 7. As a reference sample, a color vest piece, which is an asbestos-containing building material, was also immersed in pure water.

  The decomposition treatment aqueous solution containing the color vest piece, which is an asbestos-containing building material, was placed in a ball mill and reacted and ground for 18 hours while heating to 100 ° C. In the confirmation after the experiment, the color vest piece before the experiment was a lump having a length of 30 mm, a width of 20 mm, and a height of 10 mm. However, after the experiment, it was confirmed that the color vest piece was pulverized into particles of about 2 mm. By raising the temperature to 100 to 250 ° C. while applying pressure, the reaction rate can be increased, and the decomposition treatment can be performed in 3 to 18 hours depending on the temperature. Needless to say, the pulverization step may be performed in the previous step of impregnation with the decomposition treatment liquid. In addition to the pulverization process, processing and molding to an appropriate size by cutting or the like is also effective for promoting the reaction.

After 18 hours, X-ray diffraction measurement was performed to confirm the peak of chrysotile (white asbestos) crystals characteristic of asbestos. The results of X-ray diffraction spectra are shown in FIGS. The horizontal axis is the diffraction angle (2θ), and the unit is ^o (degrees). The vertical axis represents intensity, and the unit is cps (counts per second). The X-ray diffraction analysis method measures diffracted X-rays generated when X-rays are irradiated on a crystal surface. The position and intensity of the diffraction angle are specific to the crystal structure, and qualitative analysis can be performed from the diffraction pattern and quantitative analysis from the intensity. The peak at an angle of 12 degrees is a typical peak of serpentine chrysotile (white asbestos) in asbestos. When this peak decreases, it means that chrysotile crystals disappear, and it is considered that detoxification has been realized. When immersed in pure water (FIG. 2), a chrysotile crystal peak was observed around an angle of 12 degrees. However, in the aqueous solution of asbestos decomposition treatment mainly composed of polysulfide aqueous solution, no chrysotile crystal peak was observed around an angle of 12 degrees, so it was confirmed that asbestos detoxification treatment could be carried out. It was done.

At this time, asbestos is converted into a chemical substance in which asbestos Mg ₃ Si ₂ O ₅ (OH) ₄ is sulfided by a chemical reaction between sulfur and a strong alkali metal aqueous solution. From this, it is clear that this is due to the polysulfide reaction, which is a common property of Group 1 or Group 2 metal bodies, so lithium (Li), sodium (Na), potassium (K), rubidium (Rb) Any one of cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra), or a mixture thereof; A polysulfide aqueous solution in which sulfur is ion-bonded can be used as a decomposition treatment agent. At this time, since an oxidation reaction occurs in the middle, in order to accelerate the reaction, an oxidizing agent such as oxygen, hydrogen peroxide, sodium hypochlorite, or a binder such as polyisocyanate is injected into this atmosphere. It is effective in promoting the decomposition treatment reaction.

  In addition, using the aforementioned asbestos decomposition treatment agent, after immersing asbestos and asbestos-containing building materials in the asbestos decomposition treatment agent, oxygen, hydrogen peroxide, fine powder of an oxidizing agent such as sodium hypochlorite and , Using an organic binder such as polyisocyanate, stirring or chopping with a ball mill or the like, and then putting the object into a high temperature furnace and self-combustion at a high temperature furnace temperature of 400 to 900 ° C. for 30 to 120 minutes In this case, the same reaction occurs even when the high-speed oxidation treatment is performed, and the asbestos detoxification effect can be obtained.

Until now, in order to detoxify harmful asbestos (asbestos), heating asbestos-containing products has been performed. That is, by heating the asbestos-containing sample to a temperature of 850 ° C. or higher, the asbestos of the needle-like crystals is modified and decomposed to make it harmless. In heating an asbestos-containing product, high-frequency electromagnetic induction heating by microwave irradiation is used, but there is a problem that the apparatus becomes large and processing costs are high. However, in the present invention, a rapid and simple treatment method can be provided by reacting for 3 to 18 hours under a temperature condition of 100 ° C. to 250 ° C. and detoxifying.

Claims (6)

Lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), An asbestos decomposition treatment comprising, as a main component, a polysulfide aqueous solution in which sulfur is ion-bonded with any one of barium (Ba) and radium (Ra) or a mixture thereof. The decomposition treatment agent according to claim 1, wherein the asbestos has asbestos in the asbestos-containing building material as a decomposition target. The asbestos decomposition treatment agent according to claim 1 or 2, wherein asbestos or an asbestos-containing building material is impregnated, and then the decomposition is promoted by heating or using a combination of heating and an oxidizing agent. Detoxification method. 4. The method for detoxifying asbestos according to claim 3, wherein the heating is performed under a temperature condition of 100 to 250 [deg.] C. for 3 to 18 hours. After immersing asbestos or asbestos-containing building materials in the asbestos decomposition treatment agent using the asbestos decomposition treatment agent according to claim 1 or 2, using an oxidizer fine powder and an organic binder, A method for detoxifying asbestos, characterized by self-combusting in a furnace at a temperature of 400 to 900 ° C. for 30 to 120 minutes and performing high-speed oxidation treatment. Before or after impregnating asbestos and asbestos-containing building materials into the asbestos decomposition treatment agent, asbestos and asbestos-containing building materials are molded and granulated to an appropriate size in the crushing treatment process of asbestos and asbestos-containing building materials. The asbestos detoxification method according to any one of claims 3 to 5, wherein pretreatment is performed to prevent scattering and to improve handling operation performance.