JP4032075B1 - Asbestos residue treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method for asbestos residue capable of reducing processing costs by detoxifying asbestos and waste containing asbestos with low energy.
A processing method for detoxifying asbestos and waste containing asbestos, comprising a konjac solution 11 containing konjac koji powder such as konjac koji powder, granules, surimi, small chunks, paste or extract, The waste material 12 containing asbestos is kneaded in paste form 1 and the paste-like kneaded material 14 containing the konjac solution 11 and asbestos 12 is pressed to reduce the volume of the liquid material, thereby solid paper clay. Including a pressing step to make a state and a melting step in which a paper clay-like solid is heated and melted in a melting furnace, and needles peculiar to asbestos have disappeared in the solid after the melting It is characterized by that.
[Selection] Figure 1

Description

  The present invention relates to a method for treating asbestos residue generated by the operation of removing sprayed asbestos.

  Asbestos is a natural mineral fiber that includes serpentinite chrysotile and amphibole amosite. Asbestos has excellent properties such as heat resistance, chemical resistance and insulation, and has been widely used as a building material (fireproof material, heat insulating material, soundproofing material) and sprayed on the wall or ceiling of buildings. It was.

  Thus, although asbestos has excellent characteristics, a causal relationship with disease has been pointed out. That is, asbestos is a very fine glass-like needle-like fiber, and when this asbestos dust is taken into the respiratory tract, it is said to cause asbestosis, lung cancer, and malignant mesothelioma.

  Therefore, the use of sprayed asbestos is now prohibited. However, buildings that use existing asbestos will peak in the future due to reasons such as rebuilding due to their lifetime. Therefore, there is a need for safe removal of asbestos waste after removal of asbestos and after removal.

  Asbestos waste is designated as specially controlled industrial waste, so it must be treated according to the Specially Controlled Industrial Waste Treatment Standards or transported or commissioned to a licensed specially controlled industrial waste. However, a great expense for that is required.

  Currently, asbestos and the disposal method of waste containing asbestos are almost limited to the method of landfilling in the final disposal site. On the other hand, by detoxifying waste containing asbestos, it can be disposed of as ordinary industrial waste, so asbestos detoxification technologies include the closed electric furnace melting method and the slag melting method. Proposed.

Patent Document 1 discloses a detoxification process in which a closed chute is provided in a closed electric furnace, a bag containing waste asbestos material is compressed and filled in the chute furnace, and melted at a high temperature equal to or higher than the melting point of the waste asbestos material (1500 ° C.). A method is disclosed. Patent Document 2 discloses a method in which asbestos is supplied into an electric resistance melting furnace and melted at a high temperature of 1400 ° C. to 1700 ° C. to add slag without adding an additive. Furthermore, Patent Document 3 discloses a method of adding a CaF ₂ source to asbestos waste and melting it at 1300 ° C. to 1400 ° C. to vitrify it using an electric resistance heating furnace.
Japanese Patent Laid-Open No. 7-171536 Japanese Patent No. 3449929 Japanese Patent No. 3120308

  However, each of the above asbestos detoxification methods melts asbestos at a high temperature of 1000 ° C. or higher, requires enormous energy, and the melting furnace is easily hurt by high temperature heat and has a high running cost. There are disadvantages.

  This invention is made in view of the said problem, and provides the processing method of the asbestos residue which can reduce processing cost by detoxifying the waste containing asbestos and asbestos with low energy. With the goal.

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, the method for treating asbestos residue of the present invention,
A treatment method for detoxifying asbestos and waste containing asbestos,
A kneading step of kneading a konjac solution containing konjac koji products such as konjac koji powder, grains, surimi, small chunks, paste or extract, and waste containing asbestos into a paste,
Pressing the paste-like kneaded material containing the konjac solution and asbestos to discharge and reduce the volume of the liquid material by a press treatment, to a solid paper clay state,
A melting step of heating and melting a paper clay solid in a melting furnace in a range of 500 ° C. to 700 ° C . ;
The needle-shaped body peculiar to asbestos has disappeared in the solid matter after melting.

  According to the asbestos residue treatment method of the present invention, when a konjac solution is added to a waste containing asbestos and kneaded, the konjac solution gels. For this reason, generation | occurrence | production of asbestos dust can be suppressed or kneading | mixing can be performed preventing generated dust from scattering. Then, the volume can be reduced by press treatment to form a solid material of low clay, and when it is put into a melting furnace in the subsequent melting step, it is easy to put in and handling becomes convenient. Furthermore, by heating from the outside, an autothermal melting reaction of a mixture of the konjac solution and asbestos is induced. When the mixture generates heat equal to or higher than the heating temperature, the asbestos needle fibers can be eliminated, and asbestos can be rendered harmless.

  In the kneading step, the amount of the konjac solution to be mixed is preferably mixed so that the amount ratio of the konjac solution and asbestos is selected in the range of 2: 8 to 4: 6. By kneading at such a quantity ratio, generation of asbestos dust can be prevented, and asbestos can be rendered harmless by generating sufficient heat in the melting step.

  In the kneading step, when slaked lime is further added in an amount of 0.005% to 0.5% based on the weight of the kneaded product, the gelation of the konjac solution is promoted, and in the melting step, the heat treatment time is shortened to reduce the asbestos. Can be rendered harmless.

  In the melting step, the heating temperature is set within a range of 500 ° C to 700 ° C. Conventionally, in order to render asbestos harmless, it has been necessary to melt asbestos at a high temperature of 1000 ° C. or higher, but it is possible to melt asbestos and asbestos waste by lowering the temperature condition. For this reason, asbestos and asbestos waste can be rendered harmless at a lower temperature than in the past, and costs for melting and processing can be reduced.

Embodiments of the present invention will be described below with reference to the drawings.
1 to 3 are process explanatory views showing an example of a method for treating asbestos residue according to the present invention. The asbestos residue treatment method of the present invention includes a kneading step 1 (FIG. 1) for kneading a konjac solution and a waste containing asbestos, and a pressing step 2 for pressing the kneaded material obtained by this kneading step (FIG. 2). ) And a melting step 3 (FIG. 3) for melting the pressed solid.

  As shown in FIG. 1, in the kneading step 1, the konjac solution 11 and the waste 12 containing asbestos are mixed by a kneader 13 to obtain a paste-like kneaded material 14. As the kneader 13 used, a kneader, a Mueller mixer, a screw kneader, or the like can be used.

  The konjac solution 11 is a solution containing konjac koji processed products such as konjac koji powder, granules, surimi, small chunks, paste or extract. Glucomannan, the main raw material of konjac, is a polysaccharide composed of glucose and mannose. A hydrate obtained by swelling water in glucomannan solidifies to form an elastic gel when it comes into contact with an alkaline compound. It is also known that solidification is accelerated when this hydrate is heated. In the present invention, a konjac solution containing all glucomannan can be used regardless of the presence or absence of impurities such as konjac meal. For example, an aqueous solution of konjac powder obtained by drying and pulverizing konjac koji, an aqueous solution of konjac koji granulated, or an aqueous solution obtained by mixing and dissolving konjac koji paste or a small lump with water. Furthermore, not only water but also a predetermined auxiliary agent, for example, a solubilizing aid that helps dissolve konjac flour or a penetrating aid that enhances asbestos permeability is added to water, and konjac flour is dissolved in this. A solution may be made. And it can create by heating water to predetermined temperature (for example, around 40 degreeC), mixing this with a konjac powder, and making it melt | dissolve.

  When the asbestos 12 itself is made of an alkaline building material such as cement containing an alkali component, the konjac solution 11 permeates into the inside while reacting with the alkali component to form a gel. In this way, when the konjac solution 11 is added to the waste 12 containing asbestos and kneaded, the konjac solution 11 gels, so that the generation of asbestos dust is suppressed or the generated dust is prevented from scattering. can do.

  The quantity ratio of the konjac solution 11 and the asbestos 12 to be mixed is preferably adjusted to be from 2: 8 to 4: 6. In addition, when processing the asbestos waste removed by the method of the patent No. 3816944 of the applicant of the present application, the amount of the konjac solution can be reduced, and the shortage of the konjac solution can be mixed and processed. Is possible.

  Furthermore, in this kneading step 1, it is preferable to add slaked lime 15 in a range of 0.005% to 0.5% with respect to the weight of the kneaded product of the konjac solution 11 and the asbestos 12.

  After completion of the kneading step 1, as shown in FIG. 2, the kneaded product 14 containing the konjac solution 11 and the asbestos 12 is pressure-formed by press processing to discharge and reduce the liquid, and the paper clay state The press process 2 to make the solid material 21 is performed. The volume of the solid material 21 after the pressing step 2 is set to about one-tenth of the paste-like kneaded material 14. In the press molding, a generally used press press machine 22 can be used.

  After the pressing step 2, as shown in FIG. 3, a melting step 3 is performed in which the solid material 21 formed by pressure in the pressing step 2 is put into a melting furnace 31 and heated to melt. Examples of the melting furnace used here include an electric furnace such as an arc furnace, a plasma furnace, a plasma arc furnace, and a resistance furnace.

  In the melting step 3, the heating temperature is set within a range of 500 ° C. or higher and 700 ° C. or lower. If the heating temperature is less than 500 ° C., the asbestos needle fibers remain without being decomposed, and thus no harm can be expected. In the present invention, the heat treatment is performed for a time period during which the asbestos needle fibers disappear. This heating time is preferably about 4 to 6 hours.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these forms, In the range of the same identity as the invention embodied in these, it can change suitably and can implement.

Next, the present invention will be described more specifically with reference to examples.
Asbestos waste generated during asbestos removal work such as buildings and konjac solution are mixed so that the volume ratio is 3: 7, and further 0.1% slaked lime is mixed and kneaded, and paste A kneaded product is obtained. The kneaded product is subjected to pressure molding with a pressure press and then charged into an electric furnace to melt at a furnace temperature of 650 ° C. At this time, although the furnace temperature was 650 ° C., the temperature of the melt in the furnace was 750 ° C. And the asbestos needle-like fiber was decomposed | disassembled by the heating for about 4 hours, and the process ash was ceramicized.

  As a result of a qualitative test on asbestos in the ceramicized ash, it was confirmed that no asbestos was contained. Table 1 shows the results of component testing of the ceramicized ash by ICP emission spectrometry and gravimetric method.

  Next, under the same conditions as above, when slaked lime is not added, that is, only asbestos waste and konjac solution are mixed and kneaded so that the weight ratio is 3: 7. obtain. When this kneaded product is pressure-molded by a pressure press and then put into an electric furnace and subjected to a low-temperature (650 ° C.) heat treatment, it takes 6 hours for the asbestos needle fibers to be decomposed and ceramicized. Some heating was necessary.

  For comparison, when nothing was mixed under the same conditions and only asbestos waste was heated at 650 ° C. for 8 hours, the asbestos needle fibers remained. Furthermore, when asbestos waste and slaked lime were mixed without adding the konjac solution and heated at 650 ° C. for 8 hours, the asbestos needle fibers remained.

  From these results, it has been found that the konjac solution has an action of promoting the decomposition of asbestos needle fibers at a low temperature. It was also found that when konjac solution was added and slaked lime was further mixed, there was an action of decomposing asbestos needle fibers in a short time.

  The main component of asbestos is magnesium silicate, and when slaked lime is added, it reacts with silicon, which is the main component of asbestos, to cut the asbestos bond, thus promoting the decomposition of asbestos needle fibers. The solid material obtained by kneading the asbestos waste and the konjac solution and self-melting in the melting furnace generates heat, so that the temperature of the melt is higher than the furnace temperature. As a result of the heat treatment, the asbestos needle fibers can be decomposed, and asbestos detoxification is achieved.

  The treated ash after the melting process is made ceramic by detoxifying asbestos, and this fiber is mixed with less than 5% of long-fiber wollastonite (wollastonite) and molded into a seal shape. Thus, it can be reused as packing. That is, the ceramicized treated ash after melting is pulverized using a pulverizer. Then, less than 5% of wollastonite (wollastonite) is added, and if necessary, a predetermined amount of water is added and mixed with a mixer to form a sheet. The obtained sheet can be densified by punching into an arbitrary shape and compression-molding, and can be used as a packing for a flange such as an expansion pipe of a boiler.

  According to the present invention, asbestos can be made harmless by decomposing and extinguishing the asbestos needle fibers with low energy (heating temperature in the range of 500 ° C. to 700 ° C.). As a result, the cost of the melting treatment can be reduced, and the waste can be treated as general industrial waste by detoxification. And since the asbestos considered to be dangerous to a human body can be detoxified, it is excellent in economical efficiency and safety as a processing method of waste containing asbestos.

Process explanatory drawing which shows an example of the processing method of the asbestos residue which concerns on this invention. Process explanatory drawing following FIG. Process explanatory drawing following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Kneading process 2 Pressing process 3 Melting process 11 Konjac solution 12 Waste containing asbestos and asbestos 13 Kneading machine 14 Kneaded material 21 Solid material 22 Press machine 31 Melting furnace

Claims (3)

A treatment method for detoxifying asbestos and waste containing asbestos,
A kneading step of kneading the konjac solution containing konjac koji processed products such as konjac koji powder, granules, surimi, small chunks, paste or extract, and the waste containing the asbestos into a paste,
Pressing the paste-like kneaded material containing the konjac solution and asbestos to discharge and reduce the volume of the liquid material by a press treatment, to a solid paper clay state,
A melting step of heating and melting a paper clay solid in a melting furnace in a range of 500 ° C. to 700 ° C .;
A method for treating asbestos residue, characterized in that asbestos-specific needles disappear in the melted solid matter.   2. The method for treating asbestos residue according to claim 1, wherein in the kneading step, the amount of the konjac solution to be mixed is selected such that the ratio of the amount of the konjac solution to asbestos is in the range of 2: 8 to 4: 6.   The method for treating asbestos residue according to claim 1 or 2, wherein 0.005% to 0.5% of slaked lime is further added to the weight of the kneaded product in the kneading step.

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