JPH11147085A - Method for reusing incineration ash of fluidized bed incinerator and furnace bottom residue of fluidized bed type gasifying furnace as resources - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently classify the incineration ash from a fluidized bed incinerator and the furnace bottom residue of a fluidized bed type gasifying furnace into an iron material, a nonferrous metal material and aggregate to enhance the utilization value of them as resources and to improve economical efficiency while enhancing safety with respect to the aggregate to reutilize the aggregate as resources. SOLUTION: A coarse matter removing process 1 for removing coarse matter from incineration ash and furnace bottom residue (a general term 'furnace ash'), a coarse iron sorting process 1 sorting an iron component from the coarse matter, a rough sorting process 2 sorting the minus sieve matter of the coarse matter removing process by particle size, a rough crushing process 2 roughly crushing the plus sieve component of the rough sorting process, a magnetic matter removing process 3 sorting an iron component by utilizing magnetic force, an aluminum component removing process 4 utilizing an induced current to remove an aluminum component, a classifying process 5 performing classification by particle size, a long metal piece removing process 7 removing long metal pieces from classified furnace ash of 5 mm or more and a washing process 6 removing heavy metals from classified furnace ash of below 2.5 mm are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for efficiently recycling incinerated ash discharged from a fluidized-bed incinerator and bottom residues of a fluidized-bed gasifier.

[0002]

2. Description of the Related Art Fluid bed incineration ash of general waste contains many noncombustible materials in addition to ferrous materials and nonferrous metals. For example, glass, pottery, stone, sand and the like. If they can be sorted, crushed and classified efficiently, they can be used as concrete aggregates,
It can be reused as construction material, such as roadbed material for road pavement and asphalt aggregate, and as civil engineering material. In recent years, it has been considered that general waste is incinerated at a high temperature in a fluidized-bed incinerator and then treated in the following procedure. During incineration ash, iron scraps such as empty cans are magnetically selected and removed at any time. Also, coarse substances having a predetermined size or more are removed from the incinerated ash after incineration, and those other than the coarse substances are crushed as small as possible. Next, a magnetic field line is applied, and an iron material is selected therefrom. The iron material obtained here is reused as iron resources. The non-ferrous metal material is further removed from the pulverized material from which the iron material has been removed, and other than the metal material is classified according to the particle size.
A vibrating sieve or a rotary sieve (Trommel) is used for classification. The classified non-metallic material is used for aggregate. Those that do not have an appropriate use are sent to landfill.

[0003] One of the incineration techniques for general waste is a combination of a fluidized-bed gasification furnace and a swirling melting furnace, which is simply referred to as a "gasification melting furnace". However, it is easy to understand here, "fluidized bed gasifier"
I will say that. The bottom incombustibles from the fluidized bed gasifier also have almost the same properties as the incinerated ash from the fluidized bed incinerator. This furnace bottom incombustible material is in a completely dry state, and its main constituents are setmono, glass, stone, sand, and the like. Above all, metals are discharged in a non-oxidized state due to a reducing atmosphere, and thus can be said to have higher utility value than the incinerated ash. The bottom incombustibles discharged from the fluidized-bed gasifier are hereinafter referred to as "furnace residue of the fluidized-bed gasifier".

[0004]

However, the rate of reuse of the incineration ash of fluidized-bed incinerators and bottom residues of fluidized-bed gasification furnaces is extremely small in practice.
Most have been landfilled as before, and the burden on the repository has been increasing. Not all iron materials can be reused. When considered on a weight basis, the majority of magnetic materials are bulky items such as empty cans, spray cans, pipes and the like. When taken out of the incinerator, the magnetic material is clogged with sand-like substances such as fluidized sand. Empty cans filled with liquid sand have a low utility value as recycled iron resources, and in most cases they must be landfilled.

[0005] In addition, it is often the case that a long non-ferrous metal material is contained in granular aggregate for civil engineering construction obtained from incineration ash of a fluidized bed incinerator. Non-ferrous metal materials have a unique use value that is difficult to replace with other materials, and there has been a problem that such non-ferrous metal materials are not actually sufficiently used for their intended purpose. The long non-ferrous metal material contained in the incineration ash is, for example, a spring, a nail, a wire, a fork, etc. made of copper or stainless steel. Most of them have an average length of about 30 mm. Aggregates having a particle size of 5 mm to 13 mm are preferable as the aggregate for civil engineering for construction, and these aggregates contain a non-ferrous metal at a ratio of 0.3% to 6% by weight. Even if these are used as a part of the aggregate as it is, it is considered that there is no problem in itself depending on the use of the aggregate. However, when used as an asphalt aggregate for roads, for example, there is a problem in that the above-mentioned elongated metal piece jumps out on the asphalt pavement surface, impairing the workability and safety of construction. In reality, the only way to remove these was to manually remove them.

[0006] In order to sieve particles having a particle size of 5 mm to 13 mm, a sieve having a mesh size of about 13 mm is used.
It is usually difficult to imagine that an average length of 30 mm or more passes through a sieve having a mesh size of 13 mm. However, when classifying the crushed incinerated ash, if the sieve is rotated or vibrated, even a thin object with a length of about 30 mm may collide with surrounding objects on the sieve surface, sometimes vertically or diagonally in the sieve. stand up. When the longitudinal direction of the long and thin shaped object rises vertically or obliquely, and it coincides with the passing direction of the sieve, even the one having a length of about 30 mm easily passes through the sieve. In addition, heavy metals such as lead and hexavalent chromium may be mixed in the aggregate.
In the case of aggregate obtained from fluidized bed incineration ash, it is not preferable that such toxic heavy metal components may be eluted. However, investigating the toxicity of a large amount of fluidized bed incineration ash and detoxifying the entire amount would fundamentally dramatically increase the cost of recycling fluidized bed incineration ash, which is waste. It is not appropriate, as it could hurt its economics. Furnace bottom residues of a fluidized bed gasifier also have the same properties as fluidized bed incineration ash.

[0007] Accordingly, the present invention provides a utility value as a resource by efficiently classifying the incineration ash of a fluidized bed incinerator and the bottom residue of a fluidized bed gasifier into iron, non-ferrous metal and aggregate. To provide a method for recycling incinerated ash of fluidized bed incinerators and bottom residues of fluidized bed gasifiers, which can increase the safety of aggregate without impairing its economic efficiency. Aim.

[0008]

The above objects can be attained by the following means. (1) A process for removing coarse substances from incineration ash of a fluidized bed incinerator and / or furnace ash consisting of a bottom residue of a fluidized bed gasifier, and coarse iron for separating iron from the removed coarse substances The sorting process, the coarse sorting process of performing particle size sorting under the screen of the coarse substance removal process, the coarse crushing process of coarsely crushing the screen of the coarse sorting process, and the coarse screening process of sieving and the coarsely crushed material. A magnetic substance removing process for separating iron from the furnace ash using magnetic force, an aluminum removing process for removing aluminum from the furnace ash using an induced current after the magnetic substance removing process, and an aluminum removing A classification process of classifying the furnace ash after the process according to particle size, a long metal fragment removal process of removing a long metal fragment mixed from 5 mm or more of the classified furnace ash, Ash and method for recycling furnace bottom residue of the fluidized bed gasification furnace of the fluidized bed incinerator, characterized in that it consists of a cleaning process for removing heavy metals from those of less than 2.5mm of the ash.

(2) The long metal piece removing process is as follows:
The method of (1), wherein the incineration ash of the fluidized-bed incinerator and the bottom residue of the fluidized-bed gasification furnace are recycled by a vibrating sieve having slit-shaped sieves. (3) The elongate metal strip removing process includes the step of removing the classified furnace ash from a central part having a plurality of circular openings at 30-4.
Sliding downward from the upper part of the slope of the inclined plate inclined at 5 degrees, the furnace ash other than the long metal pieces is dropped from the opening,
The incinerated ash of the fluidized bed incinerator according to the above (1), wherein the elongated metal piece is passed through the opening without falling from the opening and slid to the lower end of the inclined plate to be separated. Of bottom residue from fluidized bed and fluidized bed gasifiers.

[0010]

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Here, only the case of incineration ash of a fluidized bed incinerator will be described, but the same applies to the case of a bottom residue of a fluidized bed gasifier. In the process of recycling the incineration ash of a fluidized bed incinerator as asphalt aggregate, the removal of coarse substances is performed first. This method is efficient because it initially removes those that are not suitable as recycled aggregate. For example, if most of the magnetic substances and coarse substances are removed by one rotating sieve, troubles in subsequent processes, such as bridges and abrasion, can be reduced.

The present invention also has a coarse iron sorting process for the coarse substances removed in the coarse substance removing process. In the former-stage bulky matter removal process, sand and the like in the empty cans and spray cans are discharged by the rotation effect, so that the value as iron recycling resources can be increased by the coarse iron sorting process. In the recycling of the incineration ash of a fluidized bed incinerator, the present invention uses sieves having different openings of coarse mesh, large mesh, large slit mesh, medium mesh, medium slit mesh, small mesh, and fine mesh in order. A coarse mesh is, for example, about 60 mm in diameter, a large mesh is about 13 mm in diameter,
The medium mesh has a diameter of about 5 mm, the small mesh has a diameter of about 2.5 mm, and the fine mesh has a diameter of about 0.3 mm.

FIG. 1 is a flow chart of recycling fluidized bed incineration ash. The incineration ash of the fluidized bed incinerator may be recycled, for example, according to such a flow. The flow is generally as follows. That is, a coarse substance removal process for removing coarse substances from the incineration ash of a fluidized bed incinerator, a coarse iron separation process for separating iron from the removed coarse substances, and an incineration ash below the sieve after the coarse substance removal process. Coarse crushing process to coarsely crush the sieve of the coarse separation process and the coarse separation process to sort, and a magnetic substance removal process to separate iron using magnetic force from the incinerated ash after the above process,

[0013] An aluminum component removal process for removing aluminum from the incinerated ash after the above-mentioned process using an induced current, a classification process for classifying the incinerated ash after the above process according to particle size, A cleaning process for removing heavy metals from the recycled aggregate having a particle size sufficient to pass through the small mesh among the recycled aggregates, and a medium mesh among the classified recycled aggregates The process comprises a long metal strip removal process for removing the long metal strip mixed into the aggregate having a particle size not exceeding the size of the aggregate.

Hereinafter, each process will be described in detail. Coarse-matter removal process and coarse-iron sorting process In the coarse-matter removal process, work is performed to remove coarse matter from incineration ash of a fluidized-bed incinerator. The incineration ash of the fluidized bed incinerator
It is mainly composed of ferrous and non-ferrous metals and glass, pottery, stone and sand. Using a coarse mesh rotating sieve, leave the large incinerated ash whose size exceeds the coarse mesh on the sieve,
Less incineration ash is collected under the sieve. As a result, coarse incineration ash such as iron cans and concrete pieces, such as empty cans and spray cans, which cannot be recycled as aggregates as they are, is sieved from the incineration ash. The sieved coarse incineration ash then leads to a coarse iron removal process. In the coarse iron removal process, the coarse incineration ash is separated into a magnetic substance and a non-magnetic substance by a suspended magnetic separator. For empty cans, etc., the incineration ash of the fluidized bed incinerator, which had clogged inside and prevented recycling, was discharged due to the rotating effect of the use of the rotary sieve in the bulky matter removal process at the previous stage, and high-purity coarse iron material It can be reused as a resource. Since the discharged incinerated ash is recycled as aggregate, the recycling rate of fluidized bed incinerated ash is increased.

Coarse Sorting Process and Coarse Crushing Process The incinerated ash that has passed through the coarse mesh is led to the coarse sorting process. The coarse sorting process sorts incinerated ash with a large-mesh mesh sieve. The small incineration ash that has passed through the large mesh leads to a magnetic substance removal process. The large-sized incineration ash that has not passed is led to a coarse crushing process and then to a magnetic substance removal process. The coarse crushing process is a process for coarsely crushing incinerated ash having a large particle size that has not passed through the large mesh. The coarse crushing may be performed by, for example, a shearing method. More specifically, the incinerated ash to be roughly crushed is guided on a rotary table, and crushed by a shearing effect between the rotary table and a roller whose clearance is set in advance. This crushing method is the same as that generally used for crushing clinker in a cement plant.

Magnetic substance removal process The incineration ash that has passed through the large mesh and the incineration ash that has passed through the coarse crushing process removes magnetic substances, that is, iron, from the incineration ash in the magnetic substance removal process. Here, iron is specifically, for example, a bottle lid, a nail, a spring, iron sand, etc.
Refers to iron materials of relatively small particle size that could not be removed by the coarse substance removal process. In the magnetic substance removal process, such iron is magnetically separated by a drum type magnetic separator. The magnetic separator has, for example, a permanent magnet built in half of a rotating drum, and the incinerated ash is separated into a magnetic substance and a non-magnetic substance by rotation of the drum. The iron collected by magnetic separation may be reused together with the coarse iron resources that have undergone the coarse iron removal process. The incinerated ash from which the iron has been removed is then directed to an aluminum removal process.

Aluminum Removal Process In this aluminum removal process, only aluminum is selectively separated and integrated, and this is used as aluminum resources. That is, a rotating drum for incineration ash is provided, and a rotor rotating at a higher speed than the rotating drum is provided in the rotating drum. The eddy current generated thereby repels aluminum to selectively separate the aluminum. This is a method widely used for sorting steel cans and aluminum cans. The incinerated ash from which only aluminum has been selectively removed by the aluminum removal process is further guided to a classification process, and is classified according to the particle size.

Classification process (including long metal strip removal process) In the classification process, a multi-stage vibrating sieve having a large mesh, a medium mesh, a medium slit mesh, a small mesh, and a fine mesh is used. I do. 1) Classification by Large Slit Mesh The sieve of the large slit mesh used here is, for example, a slit having a width of 11 to 12 mm and a length of 20 to 25 mm, and has a long thin shape such as a spring, a nail, a wire, or a fork. Long metal pieces that could not be removed by the aluminum removal process remain on the screen and other incinerated ash falls below the screen. The sieve mesh of this large slit mesh is, for example, 11 to 13 mm in width, preferably 11 to 12 mm, because the aggregate shape obtained by the present invention is not spherical,
For example, there are many shapes having a width of 6 to 7 mm and a length of 13 mm, and these are collected below. The reason why the length is set to 20 to 25 mm, for example, is that the long non-ferrous metal piece to be removed is an average length of 30 mm or more and is collected on a sieve. However, if the properties of the incineration ash that enters the classification process change, the appropriate choice will be made. In addition, the interval of the large slit mesh is 30 mm.
The above is provided.

2) Classification by medium mesh sieve The incinerated ash that has passed through the large slit mesh and dropped below the sieve is then led to a medium mesh sieve of about 5 mm. The medium mesh sieve is provided with a plurality of circular sieve openings having a diameter of 5 mm. Here, in the incineration ash passed through a large slit mesh width (11 to 12 mm) and length (20 to 25 mm) sieve, 5 m
The incinerated ash having a particle size of m or more is classified as recycled aggregate.
The incinerated ash having a particle size of 5 mm to 13 mm (actually, a particle size smaller than this range or a large particle size may be slightly included) on the sieve is basically made of recycled bone. Although it can be used directly as a material, it is usually often mixed with long metal pieces. Such elongated metal pieces should be removed, and the incineration ash having a particle size of 5 mm leads to a further elongated metal piece removal process.

3) Classification by Medium Slit Mesh Incineration ash having a particle size of less than 5 mm that has passed through the medium mesh sieve and dropped below the sieve is led to the medium slit mesh. The medium slit mesh has a width of 5 mm (preferably 4 mm) and a length of 10 to 10 mm.
It is formed in a 12 mm slit shape. It has basically the same structure as the large slit mesh sieve described above. A part of the long metal piece that has passed through the mesh of the medium mesh sieve is sieved here. The reason why the mesh size of the medium slit mesh is set to, for example, 4 mm in width is to collect the aggregate under the sieve, instead of the shape of the aggregate being spherical.
The reason why the length is set to 0 to 12 mm is that the long non-ferrous metal piece has an average length of about 15 to 20 mm. The interval between the slits is set to 20 mm or more. Nevertheless, non-ferrous metals may be slightly mixed in the aggregate of 2 to 5 mm, but this is not a problem. It is about 0.01% on a weight basis. However, if the properties of the incinerated ash entering the classification process change, the width and length of the slit are selected according to the properties. The removal of the long metal pieces even with the medium slit mesh sieve confirms that some of the long metal pieces are mixed in the recycled aggregate having a particle size of 5 mm or more. 5mm mentioned earlier
This proves once again that a further long metal strip removal process is required to remove the long metal strips contained in the above-mentioned recycled aggregate.

4) Classification by fine mesh sieve The incinerated ash having a particle size of less than 5 mm from which a part of the long metal piece is further removed is led to a small mesh sieve having a diameter of, for example, 2.5 mm, and then to a sieve having a diameter of 0.3 mm. Guide to fine mesh sieve. Thereby, less than 4 mm to 2.5 mm, less than 2.5 mm
Obtain incineration ash classified to 0.3 mm and less than 0.3 mm.
Note that these ranges may slightly include those having a smaller particle size or a larger particle size. The incinerated ash having a particle size of less than 4 mm to 2.5 mm is collected as recycled aggregate. The incinerated ash with a particle size of less than 0.3 mm is discharged out of the system together with the dust of each device, and it is less than 2.5 mm to 0.3 mm
The incinerated ash is washed away in a washing process to remove soluble heavy metals contained in the incinerated ash, thereby forming recycled aggregate.

Cleaning Process The cleaning process is performed, for example, as follows. A first cleaning tank and a second cleaning tank are provided, and the particle size is less than 2.5 mm to 0.3 mm
Is introduced into a first cleaning tank in which an alkaline cleaning solution having a pH of about 12 to 13 is introduced to dissolve a lead component, a hexavalent chromium component, and the like in the incinerated ash. Washing solution is pH 10-1
Overflow with 1. The incinerated ash washed with alkali is guided to the second washing tank, and neutralizes the alkali component attached in the first washing tank. An acidic cleaning solution having a pH of about 3 is introduced into the second cleaning tank. The washing solution is allowed to overflow at a pH of about 6 to 7. The first
The cleaning liquid overflowing from the second cleaning tank is guided to a drain storage tank that stores the cleaning drain.

Recycled aggregate having a particle size of 0.3 mm to less than 2.5 mm has a larger specific surface area than recycled aggregate having a particle size of 5 mm to less than 13 mm, or 2.5 mm to less than 5 mm. As such, metals such as lead and hexavalent chromium may elute. Lead has a pH of about
It is generally reported that the elution concentration is the lowest at about 8 to 10 or less, and the elution concentration (vertical axis) increases linearly in a semilogarithmic graph with respect to pH (horizontal axis) at pH 8 or lower and pH 10 or higher. Have been. Hexavalent chromium in recycled aggregate generally exists in the form of oxide. While many hydroxides of metals are insoluble in water, hexavalent chromium oxides are water soluble and do not form hydroxides. Therefore, hexavalent chromium can be easily dissolved by washing with an alkaline aqueous solution. The incineration ash of fluidized bed incinerators is generally pH 10
It is about 11 alkaline. To make the cleaning solution alkaline, many chemicals are not required for the alkaline chemical to be added.

It should be noted that wastewater containing hexavalent chromium is generally treated with a reducing agent such as ferrous sulfate or sodium bisulfite at a pH of about 2 to reduce it to trivalent chromium at a pH of about 2 and then to a pH of about 8. Methods for forming and separating soluble trivalent chromium precipitates are generally known. So 2.5mm
The incineration ash of about 0.3 mm was led to a washing tank having a pH of about 2 or less, and a test was performed in which sodium bisulfite was added to reduce the contained hexavalent chromium to trivalent chromium. However, it was judged that it was inappropriate to reduce the incineration ash having a pH of 10 to 11 to about 2 with an acid in consideration of economical aspects (a point of using a large amount of acid and a point of requiring a reducing agent).

According to the investigation of the present inventor, when the entire amount of the recycled aggregate less than 2.5 mm is introduced into the washing tank, fine particles (specifically, less than 0.3 mm) overflow while floating from the washing tank. Shed. When the washed effluent is allowed to stand still in the effluent storage tank, the incinerated ash having a small particle size settles and accumulates, making continuous operation of the washing process difficult. If the incinerated ash having a small particle size settles and accumulates, it is necessary to scrape them from the bottom of the wastewater storage tank. This hinders efficient operation and labor saving.

For this reason, in this embodiment, the particle size is 0.3
Particles smaller than mm are selectively excluded from the aggregate material. As a result, overflow of incinerated ash having a small particle size is prevented, and the recycling operation is reduced. Since particles having a diameter of less than 0.3 mm have a large specific surface area, the possibility of eluting heavy metals is extremely large as compared with particles having a larger particle diameter. Moreover, the amount of particles less than 0.3 mm in the entire incineration ash is not large. Even if only these are selectively targeted for landfill disposal as before, the load on the landfill disposal site will not be increased. As shown in FIG. 2, by the classification process of the present invention, the ratio of incineration ash having a particle diameter of less than 0.3 mm among the incineration ash that has passed through the 2.5 mm diameter fine mesh is about 10%.
It was about.

(Further) Removal of long metal pieces Although the removal of long metal pieces is performed in the above classification process, it is preferable to perform the following operation for more certainty. That is, a particle size of 5 mm to 13 m
If the incineration ash is less than m, the long metal pieces are more reliably removed by, for example, the following long metal piece removal process. FIG.
FIG. 4 is a side view of the sliding inclined plate 11 that performs a long metal side removing process. FIG. 4 is a diagram showing the arrangement relationship of the openings 13 of the sieves provided on the sliding inclined plate 11. As shown in FIG. 3, an inclined plate 11 for dropping and sliding the incineration ash 10 is provided. The inclination angle θ of the inclined plate 11 is preferably 30 degrees to 45 degrees. The falling point A of the incineration ash 10 is specified on the inclined plate 11, and a certain range from the falling point A is defined as the approaching section 12. For example, the diameter a is about 13 mm downward from the passing point of the approaching section 12. A plurality of large mesh screens 13 are opened.

The incineration ash 10 is dropped from the incineration ash discharge port 14 to a specific falling point A on the inclined plate 11, and the dropped incineration ash 10 is slid downward. The incinerated ash 10 containing the long metal pieces slides on the inclined plate 11, but the apparent specific gravity differs greatly between the long metal pieces and the other incinerated ash 10. The long metal piece slides almost in the longitudinal direction. Even when it reaches the vicinity of the opening 13 of the sieve, it passes through the opening 13 by inertia and
1 is deposited on the elongated metal piece depositing portion 15 at the lower end. It does not pass through the space between the openings 13 of the sieve and drop to the back side of the inclined plate 11. Even if the vehicle slides in the lateral direction, the average length of the elongated metal piece is larger than the diameter of the opening 13 (about 30 mm), so that there is little possibility that the metal piece passes through the opening 13. Other incineration ash 10 having a small apparent specific gravity has a small inertial force for sliding on a slope.
It passes through the openings 13 of the sieve mesh and accumulates in the incineration ash accumulation section 16 on the back side of the inclined plate 11.

It is preferable that the approaching section 12 secures a distance equal to or greater than the falling distance from the upper part of the inclined plate 11 to the falling point A of the inclined plate 11. That is, the fall distance h is 0.3 m or more.
If it is 1 m, the approach section 12 is also longer. When such a run-up section 12 is provided, even if the elongated metal piece falls vertically from the upper side of the inclined plate 11 to the drop point A of the inclined plate 11 with its longitudinal direction directed vertically, even if the metal piece is located immediately below, Of the incineration ash depositing portion 16 on the back side of the inclined plate 11 after passing through the opening 13 of FIG. That is, it is possible to slide stably on the inclined plate 11 with an inertial force.

As shown in FIG. 4, the distance b between the openings 13 of adjacent sieves is preferably, for example, 30 mm or more. By keeping this distance, it is possible to prevent an accidental situation in which the elongated metal piece passes through the opening 13 of the sieve and falls to the back side of the inclined plate 11. Distance 30mm
The reason for the above is that the average length of the mixed long metal pieces is about 30 mm, so that the flow is stabilized and rectified, and the metal pieces pass through the opening 13 of the sieve without fail. It is. Generally, recycled aggregate having a size of 5 mm or more and less than 13 mm is manufactured through a process of magnetically sorting incinerated ash from a fluidized bed incinerator, sorting aluminum by an induced current, and classifying by a sieve. According to the research of the present inventor, 0.3 to 6
It was found that about% of non-ferrous metal (aluminum and long metal pieces) was contained.

Although the incineration ash of the fluidized-bed incinerator has been described in detail above, the same treatment can be performed on the bottom residue of the fluidized-bed gasification furnace. Through a process of aluminum sorting by a sieve and classification by a sieve, a recycled aggregate of 5 mm or more and less than 13 mm can be obtained, and a furnace bottom residue of less than 0.3 mm that is not recycled can be reduced to about 10%.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. Example 1 The fluidized bed incineration ash was recycled according to the flow shown in FIG. 5, and the material balance was examined. FIG. 5 shows the results. The non-ferrous metal in FIG. 5 is composed of aluminum and a long metal piece. From FIG. 5, it was found that the amount of incinerated ash having a particle size of less than 0.3 mm was 9.5%, which was 10% or less of the whole. In the end, it was found that the amount of final waste could be drastically reduced even if only these were landfilled.

[Reference Experiment 1] A first washing tank and a second washing tank were provided, and incineration ash having a particle size of 2.5 mm or less was introduced into each washing tank in order. An alkaline cleaning solution having a pH of about 12 to 13 is introduced into the first cleaning tank.
Spilled over. An acidic cleaning solution having a pH of about 3 was introduced into the second cleaning tank, and was overflowed at a pH of about 6 to 7. The incineration ash after washing was subjected to an elution test according to the notification of the Environment Agency No. 46, and the amounts of lead and hexavalent chromium eluted were measured before and after washing. The results are shown in Table 1.

[0034]

[Table 1]

The rate at which the recycled aggregate of 0.3 mm or more and less than 2.5 mm after washing comes in contact with water and elutes lead and hexavalent chromium is determined by the environmental standard value relating to soil contamination, ie, 0.0% lead.
It was 1 ppm and 0.05 ppm or less of hexavalent chromium, indicating that sufficient safety was ensured.

Example 2 Three sets of approximately 10 kg of recycled aggregate collected to 5 mm to less than 13 mm were prepared, of which 5% (0.5 kg) of a long non-ferrous metal was mixed.
It was tested whether incineration ash could be separated under the following conditions. (1) Fall distance 300mm (2) Approach section 300mm (3) Circular opening diameter 13mm (4) Circular opening pitch (circumferential-circumferential) 300mm (5) Inclination angle 30 ° (6) Sieve length 1200mm The test was conducted three times, and the mixed state of the non-ferrous metal was examined for the upper and lower portions of the sieve. The test results are shown in Table 2. In this test, 5% of the long non-ferrous metal in the aggregate was able to reduce the contamination rate to 0.75%. This also means that non-ferrous metals in the aggregate
This means that it could be recovered at a rate of about 0%.

[0037]

[Table 2]

[0038]

According to the present invention, the incineration ash of a fluidized bed incinerator and / or
Or, for the bottom residue of fluidized-bed gasification furnace, coarse material removal process, coarse iron sorting process, coarse sorting process, coarse crushing process, magnetic material removal process, aluminum content removal process, classification process, and long metal strip removal process And a cleaning process, so that they are efficiently classified into ferrous materials, non-ferrous metal materials, and aggregates. Therefore, the utility value of each can be enhanced as a resource. Particle size 2.
The safety of the aggregate as a whole is increased by washing and removing heavy metals from incineration ash less than 5 mm. Since cleaning is not intended for all types of aggregates, it does not increase the cost of fluidized bed incineration ash and does not impair economic efficiency. It is possible to efficiently recycle incineration ash discharged from fluidized bed incinerators, which are currently mostly landfilled, and the bottom residues of fluidized bed gasifiers to reduce the load on the final disposal site and extend the life of the plant. it can.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the recycling of fluidized bed incinerated ash.

FIG. 2 is a graph showing the particle size distribution of incinerated ash that has passed through a 2.5 mm diameter fine mesh by the classification process of the present invention.

FIG. 3 is a side view of an inclined plate for performing a long metal side removing process.

FIG. 4 is a diagram showing an arrangement relationship of openings of sieves provided on an inclined plate.

FIG. 5 is a diagram showing an example of a material balance when a fluidized bed incinerated ash is subjected to a recycling process.

[Explanation of symbols]

 Reference Signs List 10 Incinerated ash 11 Inclined plate 12 Approach section 13 Opening of sieve 14 Incinerated ash discharge port 15 Deposit of long metal pieces 16 Incinerated ash deposited section

Claims (3)

[Claims] 1. A process for removing coarse substances from incineration ash of a fluidized-bed incinerator and / or furnace ash comprising a bottom residue of a fluidized-bed gasifier, and separating iron from the removed coarse substances. Coarse iron sorting process, coarse sorting process of performing particle size sorting under the sieve of the coarse material removal process, coarse crushing process of coarse crushing on the sieve of the coarse sorting process, sieving of the coarse sorting process and the coarse crushed material A magnetic material removal process for separating iron from the furnace ash using a magnetic force, an aluminum content removal process for removing aluminum from the furnace ash after the magnetic material removal process using an induced current, A classification process of classifying the furnace ash after the fraction removal process according to particle size, a long metal fragment removal process of removing a long metal fragment mixed from 5 mm or more of the classified furnace ash, and classification. And a cleaning process for removing heavy metals from less than 2.5 mm of the incinerator ash, wherein the incineration ash of a fluidized bed incinerator and the bottom residue of a fluidized bed gasifier are recycled. . 2. The incinerated ash of a fluidized bed incinerator and the furnace of a fluidized bed gasifier according to claim 1, wherein the long metal strip removing process is performed by a vibrating sieve having slit-shaped sieves. How to recycle bottom residue. 3. The long metal strip removing process slides the classified furnace ash downward from an upper part of a slope of a sloped plate having a plurality of circular openings in the center and inclined at 30 to 45 degrees. The furnace ash other than the long metal pieces is dropped from the opening, and the long metal pieces are passed through the opening without falling from the opening, slid to the lower end of the inclined plate, and separated. The method for recycling incinerated ash of a fluidized-bed incinerator and bottom residue of a fluidized-bed gasifier according to claim 1.