JP2007302482A - Method for treating asbestos-containing inorganic waste material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating waste materials of asbestos-containing inorganic materials which have been used in extensive fields including fields of building materials and of civil engineering by converting and recycling them into cement without forming asbestos dust. <P>SOLUTION: The method for treating an asbestos-containing inorganic waste material comprises heat-treating the waste material by throwing it into a cement production kiln 1 together with cement raw materials to simultaneously effect the conversion of the asbestos in the waste material into harmless minerals and the conversion of it into cement, wherein the method includes the step of subjecting the waste gas leaving the cement production kiln 1 to heating at 950°C or higher for 1 sec or longer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention converts the waste material of inorganic materials containing asbestos (asbestos), which has been used in a wide range of fields including the building materials and civil engineering fields, into cement without deteriorating the surrounding environment by asbestos dust and recycles it. The present invention relates to a processing method for use.

  Various methods have been proposed for treating waste asbestos and asbestos-containing waste materials. As a method for treating waste asbestos, conventionally, a method has been employed in which asbestos is heated at a high temperature of about 1500 ° C. to melt it and solidify it to make it asbestos. For example, in Patent Document 1, “(1) Waste asbestos discharged from a waste asbestos discharge factory is treated to prevent scattering, and the waste from a building dismantling / renovation site is directly doubled. Packed in a plastic bag and transported to an intermediate processing plant (2) At the intermediate processing site, the waste transported into the melting furnace in the melting facility is directly put together with the bag at a furnace temperature of 1500 ° C or higher. Asbestos fibers are melted and made harmless in the solidified waste asbestos “slag” and “carel”. (3) After melting and solidifying, the detoxified slag, etc. is separated from the scope of specially controlled industrial waste and becomes a substance that falls under “glass waste and ceramic waste” and can be buried in a stable final disposal site. "A method for treating waste asbestos". However, there is a problem that if asbestos is melted and solidified and buried in the final disposal site, it cannot be recycled as a resource.

  In addition, as a method for treating asbestos-containing waste materials, a technique of converting to a hydraulic material and reusing it has been proposed. For example, Patent Document 2 is a heat-treated product of an asbestos-cement product obtained by heat-treating an asbestos-cement product at a temperature of 600 to 1450 ° C. for 15 minutes to 2 hours, and has no asbestos peak due to X-ray diffraction. And the hydraulic powder composition characterized by the absence of glassy solidified material is disclosed. However, when asbestos-cement products are actually heat-treated, there is a problem that asbestos dust is generated, so that countermeasures are important. However, Patent Document 2 does not disclose anything about measures against asbestos dust.

  Patent Document 3 discloses a cement manufacturing method using a rotary kiln, which is characterized by treating asbestos waste material and cement raw material in a calcined zone in the rotary kiln. However, in Patent Document 3, since the asbestos waste material is introduced from the clinker outlet side of the rotary kiln, it is necessary to pulverize it in advance, and there is a problem that the surrounding environment is deteriorated in the pretreatment stage.

JP-A-10-337547 Japanese Patent No. 3198148 JP-A-9-86982

  Accordingly, the object of the present invention is to remove waste materials of inorganic materials containing asbestos (asbestos) that have been used in a wide range of fields including the building materials and civil engineering fields, without deteriorating the surrounding environment due to asbestos dust. It is providing the processing method for converting into cement, such as, and reusing.

In the present invention, the waste material of the inorganic material containing asbestos is put into a kiln for cement production together with the cement raw material and heat-treated, thereby converting the asbestos in the waste material into non-asbestos and converting it into cement. In the processing method of inorganic waste materials containing asbestos,
The present invention provides a method for treating an inorganic waste material, comprising a step of heating the exhaust gas emitted from the kiln for cement production to 950 ° C. or more for 1 second or more.

  In the present invention, the cement production kiln is a rotary kiln having a preheater and a calcining furnace, and the exhaust gas flowing in the preheater and / or the calcining furnace has a temperature of 950 ° C. or more and 1 second or more. The present invention provides a method for treating an inorganic waste material, which comprises performing a heating step.

  In addition, the present invention adjusts the particle size of the waste material so that the content ratio of the fine powder having a maximum dimension of less than 200 mm and a particle size of less than 1 mm is 5% or less, and the total amount of the waste material and the cement raw material The ratio of the waste material occupying the weight of the inorganic waste material is adjusted so that the mass ratio in a dry state is 5% or less, and the cement raw material is introduced into the cement production kiln from the kiln bottom of the kiln. A processing method is provided.

  In the present invention, the waste material whose particle size is adjusted such that the content ratio of the fine powder having a maximum dimension of less than 200 mm and a particle diameter of less than 1 mm is 5% or less is contained in the fine powder having a particle diameter of less than 1 mm. The present invention provides a method for treating an inorganic waste material, wherein the waste material is obtained by solidifying a waste material having a ratio exceeding 5% using an inorganic binder.

  In the present invention, since the exhaust gas emitted from the kiln for producing cement is heated at 950 ° C. or higher for 1 second or longer, asbestos in the exhaust gas can be completely made non-asbestos. Therefore, the waste materials of inorganic materials containing asbestos (asbestos) that have been used in a wide range of fields including the building materials and civil engineering fields are converted to cement without deteriorating the surrounding environment by asbestos dust and reused. be able to.

  In the present invention, the inorganic material containing asbestos is an inorganic material in which asbestos is used as at least a part of the fiber raw material. For example, the matrix is a cement hydrate or a calcareous raw material and a siliceous raw material. Is a material composed of calcium silicate hydrate and the like produced by autoclave curing, and various fillers and admixtures are often used together as necessary. Specific examples include asbestos cement boards such as asbestos slate and asbestos cement roofing materials, asbestos cement calcium silicate boards, cement tile materials, chimney materials, and extrusion molding materials. Inorganic materials containing asbestos have been widely used as materials for buildings and structures, and a large amount of such waste materials are generated when dismantling and repairing buildings and structures. In order to reuse this asbestos-containing inorganic material waste material (hereinafter simply referred to as waste material) as a resource, the asbestos contained in the waste material should be made non-asbestos and a material or state that is easy to reuse. It is important to convert. As a method of performing such treatment, a method of heating together with a cement raw material using a cement production kiln is suitable, but as described above, simply putting waste material into a cement production kiln and firing it. The exhaust gas from the kiln contained asbestos dust, which deteriorated the surrounding environment.

Therefore, the present invention is characterized by having a step of heating the exhaust gas emitted from the kiln for producing cement at 950 ° C. or higher for 1 second or longer (hereinafter sometimes referred to as the heating step of the present invention).
FIG. 1 is a schematic diagram for explaining an embodiment of the present invention. In addition, although FIG. 1 demonstrates as an example the case where a rotary kiln is used as a kiln for cement manufacture, the kiln used for this invention is not limited to a rotary kiln.
In FIG. 1, the rotary kiln 1 mainly includes a preheater 11, a calcining furnace 12, a calcining furnace burner 121, a kiln main body 13, a combustion burner 131, and a clinker cooler 14. Such a rotary kiln is generally called a rotary kiln with a new suspension preheater (NSP). As a raw material for cement, limestone is mainly used, and other materials such as clay, silica, and iron are used. The coarsely crushed, mixed and finely crushed cement raw material is first put into the preheater 11 and heated. That is, the cement raw material descends the cyclones 111, 112, 113, and 114 in this order and is heated. The heating of the cement raw material in the cyclone is performed by supplying hot air. Subsequently, the cement raw material that has passed through the preheater 11 is further heated in the calcining furnace 12 by the calcining furnace burner 121, put into the kiln main body 13, and fired.

The waste material is input from the kiln bottom 132 of the kiln main body, moves to the kiln main body 13 together with the cement raw material, and is fired. In general, the preheater 11 is configured to be applied to a powdery raw material. Therefore, if the waste material is to be input from the preheater 11, this must be pulverized, and a large amount of asbestos dust is generated. Since it occurs, it is not preferable. Therefore, it is preferable to throw in the waste material from the kiln bottom 132 of the kiln body. The kiln body 13 is rotating at a rate of 2 to 3 revolutions per minute, and the cement raw material and waste materials that are input are baked at a high temperature of about 1450 ° C. while moving in the exit direction of the kiln body 13. It becomes a sintered body (cement clinker), is cooled by the clinker cooler 14, and is taken out from the rotary kiln 1. The cement raw material and the waste material are baked in the kiln main body 13 by burning pulverized coal from the kiln main body 13 toward the kiln bottom direction 132 toward the kiln bottom direction 132 and feeding it into the kiln main body 13. The kiln front is the side from which the sintered body of the kiln main body 13 is taken out, and the kiln bottom is the side to which the cement raw material is charged.
The temperature inside the kiln main body 13 is about 950 to 1050 ° C. at the kiln bottom 132, the maximum temperature of the middle part is about 1450 ° C., and the temperature before the kiln 133 is about 1200 ° C. Gypsum is added to the sintered body thus obtained as necessary for the purpose of adjusting the setting time of the cement, and the cement is obtained by pulverizing with a finishing pulverizer (finishing mill).

  The exhaust gas from the kiln main body 13 moves in the direction opposite to the direction of travel of the cement raw material and the waste material, and rises in the order of the calcining furnace 12 and the cyclones 114, 113, 112, and 111 of the preheater 11, After that, it is discharged from the exhaust port 21. At this time, the powder moving together with the exhaust gas is lowered and returned toward the kiln main body 13 by the action of the cyclone or the introduction of the cement raw material. However, there is a possibility that the fine powder content of the waste material passes through the cyclone as it is and goes to the exhaust port 21, and even if it passes through the dust collector, the possibility of asbestos being discharged from there is not zero. Therefore, in the present invention, the exhaust gas is heated at 950 ° C. or higher for 1 second or longer to make asbestos contained in the exhaust gas non-asbestos.

  As described above, in the heating step of the present invention, the exhaust gas is heated at 950 ° C. or more and for 1 second or more, preferably 950 to 1100 ° C. and 1 to 2 seconds, more preferably 1000 to 1200 ° C. Heating is performed for 1100 and 1-2 seconds. By the heating process of the present invention, chrysotile asbestos (sometimes called white asbestos) is changed from forsterite to enstatite, and amosite asbestos (sometimes called tea asbestos) is enstatite + crinoferrosilite + hematite + magnetite + To quartz, crocidolite asbestos (sometimes called blue asbestos) transforms into hematite + amorphous phase and is completely non-asbestos.

In order to heat the exhaust gas at 950 ° C. or higher and for 1 second or longer, for example, a method of increasing the temperature of the calciner 12 and / or the preheater 11 is preferably applied. In general, the temperature of the preheater 11 is 400 to 900 ° C., and the temperature in the cyclone 114 and the calcining furnace 12 is 850 to 900 ° C. The pot bottom 132 has a temperature of 950 to 1050 ° C., but the flow rate from the pot bottom 132 to the cyclone 114 and the calciner 12 is about 30 to 40 m per second, and the time for heating at 950 ° or more is about 0.3 to 0.00. About 5 seconds, the conventional rotary kiln cannot perform the heating process of the present invention.
Specific means for increasing the temperature of the calciner 12 include a method of increasing the fuel supplied to the calciner burner 121 and a method of suppressing the input amount of raw materials. The temperature of the preheater 11 is increased. As specific means, in addition to raising the temperature of the calciner 12, there are a method of raising the combustion burner 131 and a method of raising the temperature of the clinker cooler 14 to increase the amount of air extracted therefrom.
Alternatively, any other heating device that performs the heating process of the present invention may be installed near the calcining furnace 12 and / or the preheater 11 or further outside the exhaust port 21.
Further, in order to carry out the heating process of the present invention in the calcining furnace 12 and / or the preheater 11, the residence time of the exhaust gas therein is set to 1 second or more, and the asbestos contained in the exhaust gas is completely removed. Need to be asbestos. The method for controlling the residence time of the exhaust gas is not particularly limited. For example, it is desirable to appropriately adjust the flow rate of the exhaust gas. As a means for controlling the flow rate of the exhaust gas, for example, a method of suppressing the suction exhaust amount in the duct 21 before the dust collector can be mentioned.

  In order to further improve the effect of the heating process of the present invention, that is, the effect of completely converting the asbestos contained in the exhaust gas into non-asbestos, and efficiently converting the waste material into cement and reusing it, the maximum size of the waste material is less than 200 mm. The particle size is adjusted so that the content ratio of fine powder having a particle size of less than 1 mm is 5% or less and the water content is adjusted to 20% or less, and the mass of the waste material in a dry state is 5 to 30 kg / bag. It is preferable to pack the bag in the range and put it into the rotary kiln 1.

The apparatus and method for adjusting the particle size of the waste material so that the maximum size is less than 200 mm and the content ratio of the fine powder having a particle size of less than 1 mm is 5% or less are not particularly limited. In the case where the maximum size of the waste material is 200 mm or more, the particle size may be adjusted so as to satisfy the above conditions by crushing the waste material using a known crusher such as a hammer crusher or a devil crusher. In this case, when crushing the waste material, it is also effective to perform crushing while sprinkling the waste material in order to suppress the generation of dust. When the waste material is fine powder having a particle size of less than 1 mm or the content ratio of fine powder having a particle size of less than 1 mm exceeds 5%, an inorganic binder such as cement and water are added and mixed. The particle size may be adjusted so that the particle size is 1 mm or more and the maximum dimension is less than 200 mm by granulation or the like. When the maximum size of the waste material is 200 mm or more, it is not preferable because crushing of the waste material is difficult to pack and there is a risk of damaging the inside of the rotary kiln due to a drop impact when the rotary kiln is charged. Moreover, when the content ratio of the fine powder having a particle size of less than 1 mm exceeds 5%, asbestos dust is easily generated when the waste material is introduced into the rotary kiln 1 from the kiln bottom. Moreover, when crushing waste materials, it is necessary to provide the crusher with a dust collector, and the dust of waste materials collected by the dust collector also corresponds to the waste materials of inorganic materials containing asbestos. Since this dust contains a large amount of fine powder having a particle size of less than 1 mm, in the treatment of this dust, as described above, it is mixed with cement and water, granulated, etc., and solidified to have a particle size of 1 mm or more and maximum The particle size may be adjusted so that the dimension is less than 200 mm.

  The waste material whose particle size has been adjusted in this way is fed into the kiln from the kiln bottom 132 of the rotary kiln 1. As a charging method, a crushing device is provided continuously at the charging port before the charging port to the kiln butt, and the waste material transported as it is in the original shape is crushed in the kiln while crushing to the predetermined conditions described above. There are a method of charging and a method of packing the waste material crushed under the above-mentioned predetermined conditions into a kiln. In the case of putting in a bag, it is preferable to adjust the moisture content of the waste material to 20% or less and pack the waste material in a range of 5 to 30 kg as a mass in a dry state. The reason for packing the waste material is to prevent the generation of asbestos dust before the waste material is put into the kiln from the kiln bottom 132 of the rotary kiln 1. As a bag body for bagging crushed waste material, it is flammable without the risk of dioxin generation, easy to bag waste material, and excellent handling properties after bagging waste material For example, a resin such as polyester having a thickness of 0.1 to 0.3 mm, a sandbag, a bag made of kraft paper with laminated paper, etc. In view of hermeticity, a bag made of resin such as polyester or kraft paper with laminated paper is suitable. If the water content of the waste material packed in the bag exceeds 20%, the waste material explodes due to the volume expansion when the water content contained in the waste material suddenly changes to water vapor when the waste material is introduced from the kiln bottom 132 of the rotary kiln 1. Asbestos dust is likely to be generated, and there is a risk of adversely affecting the rotary kiln 1. Therefore, it is preferable to adjust the moisture content of the waste material whose particle size has been adjusted to 20% or less and pack it in a bag. When the moisture content is high, the moisture content may be adjusted by a heat drying method using infrared rays, a heat drying method using microwaves, or the like. Moreover, it is not preferable that the mass per bag of the waste material packed in the bag exceeds 30 kg because work efficiency is lowered. Further, if the mass of the waste material per bag of the waste material packed in bags is less than 5 kg, it is not preferable because the cost required for bagging becomes too high. In addition, the moisture content in this invention means (mass of the object in the state containing water-mass of the object in a dry state) / mass of the object in a dry state x 100 (%). The dry state is obtained after heating the object at 105 ° C. for 24 hours.

The ratio of the waste material to the total amount of the waste material and cement raw material put into the rotary kiln 1 is preferably 5% or less as a mass ratio in a dry state. When the mass ratio of the waste material exceeds 5%, it is not preferable because the obtained cement has a large variation in performance and becomes difficult to use as cement.

  In the case where a crushing device is provided continuously at the charging port and the waste material is put into the kiln, the waste material crushed by the crushing device is directly put into the kiln from the hook bottom 132, and the waste material is packaged in a bag. In the case of charging to the kiln bottom 132, a belt conveyor or the like may be used. The waste material thrown into the rotary kiln from the kiln bottom 132 of the rotary kiln 1 together with the cement raw material heated by the preheater 11 is heated at 950 to 1450 ° C. for 30 to 60 minutes while rotating in the rotary kiln 13. Within the range of this heat treatment, it is preferable that the maximum temperature is 1200 ° C. or higher and the time for heating at a temperature of 1200 ° C. or higher is 15 minutes or longer. As a result of this heat treatment, asbestos in the waste material is made non-asbestos and fired together with the cement raw material to form a sintered body (cement clinker). Since the temperature and time conditions for the heat treatment are general cement firing conditions, the waste material can be treated under conditions for producing ordinary cement.

  The heat treatment of the waste material in the rotary kiln 13 will be further described. The waste material introduced from the kiln bottom 132 of the rotary kiln 13 together with the cement raw material heated in the preheater 11 and the calcining furnace 12 is burned by the bag body and the rotary kiln 1. While exposed inside, the water in the waste material evaporates. On the other hand, the hot air blown into the rotary kiln 13 by burning pulverized coal from the direction before the kiln 133 is discharged as exhaust gas from the kiln bottom 132 side of the rotary kiln 13 toward the exhaust port 21. As described above, asbestos in the exhaust gas is completely made non-asbestos by carrying out the heating step. The waste material thrown into the rotary kiln 1 from the kiln bottom 132 moves from the kiln bottom 132 side to the front kiln 133 side while rotating in the rotary kiln 13, and is mixed with the cement raw material at 950 to 1450 ° C. for 30 to 60 minutes. Heat treatment is performed to make asbestos non-asbestos, and the components constituting the waste material are fired together with the cement raw material to form a sintered body. The temperature in the rotary kiln 13 is about 950 to 1050 ° C. at the kiln bottom 132, the maximum temperature is 1450 ° C., and the temperature before the kiln 133 is about 1200 ° C. In order to obtain a sintered body, it is preferable that the maximum temperature is set to 1200 ° C. or higher and the time for heating at a temperature of 1200 ° C. or higher is set to 15 minutes or longer within the range of the heat treatment. Since the inside of the rotary kiln 13 is high temperature, even if asbestos dust is generated in the rotary kiln 13, it is made non-asbestos in a very short time.

The chemical composition of the waste material contains lime and silicic acid as main components, and contains alumina, magnesia and iron as subcomponents, and the molar ratio of each component is CaO / SiO ₂ = 0.5 to 3, When Al ₂ O ₃ / SiO ₂ = 0 to 2, MgO / SiO ₂ = 0 to 2 and Fe ₂ O ₃ / SiO ₂ = 0 to 2, the matrix fixing asbestos in the waste material is heated. Therefore, the asbestos is fixed to the matrix until it is made non-asbestos by heating, which is more effective in preventing the generation of asbestos dust.

  The sintered body thus obtained is cooled by the clinker cooler 14 and taken out from the rotary kiln 13 as in the case of ordinary cement production, and after being cooled in the cooler, powdered and regenerated as cement. . Needless to say, gypsum can be added for the purpose of adjusting the setting time of the regenerated cement.

By the way, the particle size adjustment of the waste material accompanied by the crushing treatment may be performed in an asbestos-containing waste material crushing treatment facility in which measures against asbestos are taken in order to prevent scattering of asbestos dust. In this case, the particle size of the waste material is adjusted so that the content ratio of fine powder having a maximum dimension of less than 200 mm and a particle size of less than 1 mm is 5% or less, and the moisture content is adjusted to 20% or less. Asbestos-containing waste asbestos-containing waste material crushing facility separate from the cement manufacturing plant, the step of filling the waste material in a dry mass range of 5-30 kg / bag (hereinafter referred to as the first step) It can be carried out in a waste material crushing treatment plant. In addition, the waste material packed in a bag can be stored in a state of being packed in a storage place in an asbestos-containing waste material crushing treatment plant, if necessary. In addition, the asbestos-containing waste material crushing treatment plant where the asbestos countermeasure was taken here refers to the facility managed with the following requirements.
(1) As a crushing facility for “debris” limited to Article 8-1-1, Paragraph 2 of Article 7 of the Order for Enforcement of the Law on Waste Disposal and Cleaning (Cabinet Order No. 300 of 1971) The facility is permitted to be installed by the local government having jurisdiction over the installation location.
(2) In accordance with the provisions of Article 5, Paragraph 1 of the Ordinance for the Prevention of Disorders of Specified Chemical Substances (Ministry of Labor Ordinance No. 39 of 1947), a local exhaust system having the requirements of Article 7 of the Regulations was installed. Be an indoor work place.
(3) In accordance with the provisions of the Ordinance for the Prevention of Disorders of Specified Chemical Substances (Ministry of Labor Ordinance No. 39 of 1947), appointing the chief operator of specified chemical substances, etc. .

  The implementation of the first step is not limited to the asbestos-containing waste material crushing treatment plant. For example, a mobile vehicle having an asbestos-containing waste material crushing treatment facility and equipment for performing the first step is used as a waste material. It may be dispatched to the place of occurrence.

  When the first step is performed in the asbestos-containing waste material crushing treatment plant, the step of transporting the bagged waste material from the asbestos-containing waste material crushing treatment plant to the cement manufacturing plant is the second step. During transportation, it must be ensured that no asbestos dust is generated. In addition, it is necessary to be able to treat the above-described waste material using a cement manufacturing kiln without providing special equipment for measures against asbestos dust. For this reason, it is preferable that the transportation means used in the second step is provided with a dust collection facility that does not discharge dust having a maximum dimension of 5 μm or more to the outside. In order not to discharge dust having a maximum size of 5 μm or more, for example, a filter such as a hepa filter is attached to the dust collection facility, and the exhaust from the dust collection facility to the outside may be performed after the dust is removed by the filter.

  As a means of transportation used in the second step, a storage for storing the waste material packed in the first step, and collecting the dust in the storage and discharging dust having a maximum dimension of 5 μm or more to the outside. And a vehicle equipped with a dust collecting device for preventing the above. The waste material packed in the first step is stored in a storage provided in the transport means via a belt conveyor or the like, and is transported to a cement manufacturing plant for performing the third step. In the second step, the dust collected in the dust collector provided in the transportation means can be returned to the first step and handled as a crushed waste material.

  Thus, for the waste material transported to the cement factory, as described above, the ratio of the waste material to the total amount of the waste material and the cement raw material is adjusted to be in a range of 5% in a dry mass ratio, The waste material is packed in a kiln for cement production together with the cement raw material in a state of being packed in a bag, and is heated at 950 to 1450 ° C. for 30 to 60 minutes to obtain a sintered body. The step of powdering (third step) is performed.

Hereinafter, the present invention will be further described by way of examples and comparative examples.
(Reference Example 1)
5g of asbestos-containing corrugated plate containing chrysotile and amosite (crushed to under 590μm) manufactured in 1965, burned in a fluidized-fired furnace experimental device that reproduced the exhaust gas flow from the bottom of a kiln for cement production We investigated how much heating was necessary to make the asbestos scattered as dust non-asbestos.
FIG. 2 is a schematic diagram of the fluidized-fired furnace experimental apparatus used in this reference example. The experimental apparatus 100 includes a sample heating zone 101 and a sample recovery zone 102. The sample heating zone 101 is composed of a SUS tube having an outer tube of 150 mm and an inner tube of 80 mm, and extends in the vertical direction (5 m). A main burner 31 is provided at the lowermost part of the sample heating zone 101, and auxiliary burners 32, 33, 34, and 35 are provided at the side portions. By heating the gaps between the outer tube and the inner tube, the temperature in the inner tube is increased. Can be adjusted. A plurality of thermometers and anemometers (not shown) are provided in the inner tube so that the heating temperature in the inner tube and the residence time of the sample can be measured. Further, the experimental apparatus 100 is provided with a sample insertion port 41. A cyclone 50 is provided between the sample heating zone 101 and the sample recovery zone 102 and both zones are connected. The cyclone 50 collects dust that floats with the exhaust gas and does not go to the sample collection zone 102. The sample collection zone 102 is composed of a 50 mm steel pipe, extends in the lateral direction, and has a sample collection unit 61 at a position 6 m from the connecting portion of the cyclone 50. The sample collection unit 61 is equipped with a glass fiber filter paper inside, and can collect dust in the exhaust gas. Note that a blower (not shown) is installed downstream of the sample recovery unit to suck exhaust gas in the discharge direction.
Whether or not chrysotile and amosite are present in the collected sample when the sample is held for 1 second at 750 ° C., 800 ° C., 850 ° C., 900 ° C., and 950 ° C. using the experimental apparatus 100 It was confirmed by microscopic observation by an X-ray diffraction test and a disperse staining method. As a result, the disappearance of chrysotile was confirmed by heating at 850 ° C., but the presence of amosite was also confirmed by heating at 750 ° C., 800 ° C., 850 ° C., and 900 ° C. However, disappearance was confirmed by heating at 950 ° C. for 1 second. From the above, it was confirmed that heating at 950 ° C. or higher and 1 second or longer is necessary to completely convert the exhaust gas containing asbestos into non-asbestos.

Example 1
Corrugated asbestos slate scrap (constructed as a large corrugated plate of JIS-A-5403 at that time) that was constructed as an outer wall of a warehouse about 25 years ago as a waste material of inorganic materials containing asbestos. Applicable) was used.
First step: In an asbestos-containing waste material crushing treatment plant equipped with a demon tooth crusher as a crushing device, the waste material is crushed by being sprinkled on a belt conveyor while being sprinkled on a belt crusher, and classified by a sieving machine having an opening of 200 mm. And the thing with a particle size of 200 mm or more was crushed so that the largest dimension might be less than 200 mm by repeating sending to a devil crusher again and grind | pulverizing. The content ratio of the fine powder having a particle size of less than 1 mm contained in the crushed waste material was measured using a sieving machine having an opening of 1 mm, and was about 1%. While adjusting the moisture content to about 10% by heat drying method using infrared rays, the crushed waste material is sent to a bag made of polypropylene and made of polypropylene so that the dry mass of the waste material becomes 20 kg. Packed in a bag. In addition, dust was collected by the installed dust collector from the demon tooth crusher to the end of bagging, and no asbestos dust was generated.
Second step: The packaged waste material was loaded as a transportation means on a truck equipped with a storage and a dust collector equipped with a hepa filter for collecting dust inside the storage, and transported to a cement manufacturing factory. . In the second step, asbestos dust was not discharged outside the truck.
Third step: The third step was performed in a cement manufacturing plant using a rotary kiln with a cement firing capacity of 100 tons / hour.
The rotary kiln used in this example is the rotary kiln 1 with NSP described in FIG.
Limestone, clay, and copper calami were used as the cement raw material, and the waste material was 1% and the cement raw material was 99% in the dry mass ratio. The waste material packed in the bag together with the cement raw material heated by the preheater 11 is continuously fed into the rotary kiln 1 from the kiln bottom 132 of the rotary kiln operating at a rate of 1000 kg / hr. It was. The operating condition of the rotary kiln 1 is that the temperature is 950 ° C. at the kiln butt 132 and 1450 ° C. at the kiln front 133, and the elapsed time from the introduction of the kiln butt 132 to the removal from the kiln 132 as a sintered body is 45 minutes. Yes, the heating time of 1200 ° C. or higher was 30 minutes.
The temperature of the calciner 12 was set to 950 ° C. by adjusting the fuel supplied to the calciner burner 121, and the temperatures of the cyclones 114 and 113 were set to 950 ° C. The temperature of the cyclone was adjusted by adjusting the exhaust gas flow rate. Further, the flow rate of the exhaust gas exiting from the heating kiln main body 13 was adjusted so that the exhaust gas stayed in the calcining furnace 12 for 1 to 2 seconds and the cyclones 114 and 113 for 1 to 2 seconds. Dust contained in the exhaust gas was collected at the exhaust port 21 and whether or not asbestos was present in the dust was confirmed by an X-ray diffraction test. As a result, no diffraction peak derived from asbestos was observed. Therefore, observation was performed using microscopic observation by a disperse staining method, but no asbestos was observed.

On the other hand, the sintered body obtained by the heat treatment in the rotary kiln 1 was taken out of the rotary kiln 1 through the clinker cooler 14, cooled in a cooler, and then pulverized by a normal cement grinding process. Prior to pulverization, 3% gypsum was added to the sintered body at a mass ratio (external ratio) to the cement raw material.
Ten samples of the obtained powder were collected and subjected to an X-ray diffraction test. As a result, no asbestos diffraction peak was observed. Therefore, observation was performed using microscopic observation by a disperse staining method, but no asbestos was observed. Therefore, it was confirmed that the asbestos was non-asbestos-treated. Next, as a result of carrying out the compressive strength test (7 days) for each sample based on JIS R 5201, the compressive strength of all the samples exceeded 22.5 N / mm ^2. It had a performance corresponding to ordinary Portland cement specified in R 5210.

  According to the present invention, waste materials of inorganic materials containing asbestos (asbestos) that have been used in a wide range of fields including the building materials and civil engineering fields are converted into cement without generating asbestos dust and reused. The processing method for doing can be provided.

It is the schematic for demonstrating one Embodiment of this invention. It is the schematic of the experimental apparatus used by the reference example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary kiln 11 Preheater 111,112,113,114 Cyclone 12 Calciner 121 Calciner burner 13 Kiln body 131 Combustion burner 132 Kiln bottom 133 In front of kiln 14 Clinker cooler 100 Experimental apparatus 101 Sample heating zone 102 Sample recovery zone 21 Duct before dust collection 31 Main burner 32, 33, 34, 35 Auxiliary burner 41 Sample inlet 50 Cyclone 61 Sample recovery unit

Claims (4)

Asbestos containing inorganic material containing asbestos is put into a kiln for cement production together with cement raw material and heat treated, thereby converting the asbestos in the waste material into non-asbestos and converting it into cement. In the processing method of inorganic waste materials,
A method for treating an inorganic waste material, comprising a step of heating the exhaust gas emitted from the kiln for cement production to 950 ° C. or more for 1 second or more.   The cement production kiln is a rotary kiln equipped with a preheater and a calcining furnace, and the exhaust gas flowing in the preheater and / or the calcining furnace is heated at 950 ° C. or more for 1 second or more. The method for treating an inorganic waste material according to claim 1, wherein the method is performed.   The particle size of the waste material is adjusted so that the content ratio of the fine powder having a maximum dimension of less than 200 mm and a particle size of less than 1 mm is 5% or less, and the ratio of the waste material to the total amount of the waste material and the cement raw material Is adjusted to be 5% or less in a mass ratio in a dry state, and the waste material is put into the cement production kiln together with a cement raw material from the kiln bottom of the kiln. Treatment method for inorganic waste materials.   The waste material whose particle size is adjusted so that the content ratio of the fine powder having a maximum dimension of less than 200 mm and a particle diameter of less than 1 mm is 5% or less is 5% in the content ratio of the fine powder having a particle diameter of less than 1 mm. The method for treating an inorganic waste material according to claim 3, wherein the waste material that exceeds the amount is solidified using an inorganic binder.

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