JP2022142609A - Method for treating incineration main ash - Google Patents

Abstract

To provide an efficient method for treating incineration main ash.SOLUTION: A method for treating incineration main ash includes: a first process of adding water to incineration main ash having 10 mm or smaller of particle size; a second process of dehydrating the incineration main ash to which water has been added through centrifugal separation; a third process of separating the dehydrated incineration main ash into heavy products and light products through sorting through specific gravity and recovering the light products as cement raw materials; and a fourth process of separating the heavy products sorted in the third process into non-magnetic products and magnetic products through sorting through magnetic force, recovering the non-magnetic products as nonferrous refining raw materials and recovering the magnetic products as electric furnace and blast furnace raw materials.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for treating incineration bottom ash.

Incineration bottom ash is discharged from the hearth of an incinerator for municipal waste, etc., and the discharged incineration bottom ash is landfilled as it is in a controlled disposal site as general waste. However, in recent years, since the remaining capacity of final landfill disposal sites has been decreasing, various studies have been made on effective utilization of incineration bottom ash.

For example, as a method of processing incineration bottom ash, after incineration bottom ash with a maximum particle size of 5 mm or less is separated into conductors and nonconductors by eddy current sorting, the conductors are separated into high specific gravity substances and low specific gravity substances by specific gravity difference separation. However, it has been proposed to recover precious metals as high specific gravity substances and recover aluminum as low specific gravity substances (Patent Document 1). In addition, after adding water to incinerator bottom ash to make slurry, the incineration ash slurry is separated into slurry containing coarse particles and slurry containing fine particles, and the slurry containing coarse particles is wet specific gravity sorted to recover precious metals. However, after desalting the slurry containing fine particles, it has been proposed to recycle it as a raw material for cement (Patent Document 2).

JP 2018-58059 A JP 2020-110739 A

However, since bottom ash contains a lot of water and is in a moist state, there are the following problems in processing the bottom ash. That is, if the incinerator bottom ash is subjected to physical sorting in a wet state, water seeps out on the surface of the incineration bottom ash, so the incineration bottom ash is united with each other and aggregated, causing adhesion to equipment etc., clogging, etc. normal driving becomes difficult. As a countermeasure, for example, it is conceivable to apply heat energy from a dryer or hydration heat energy by adding an admixture to the incinerated bottom ash to remove moisture, but the method using heat energy does not consume much energy. is huge and expensive, and the method using mixed materials requires a lot of time to remove moisture, which greatly reduces the processing capacity of incineration bottom ash per unit time and shortens the processing time. If the amount of the mixed material is increased, the cost becomes high. Furthermore, a method of dehydrating the incinerator bottom ash as it is with a centrifuge to reduce the water content is also conceivable, but since the incinerator bottom ash contains coarse particles such as metals and slag, the wear of the centrifuge and the damage to the filter cloth are severe. Dehydration is difficult.
An object of the present invention is to provide an efficient method for treating incinerated bottom ash.

In the technical field, a centrifuge is usually used for the purpose of dehydrating incinerator bottom ash, as described above, but the present inventors, before putting the incinerator bottom ash into the centrifuge, Adding water to incinerator bottom ash not only makes it easier to supply to the centrifugal separator, but also promotes the separation of coarse particles and fine particles by centrifugation, so valuables can be efficiently sorted out from incinerator bottom ash. I found that it can be recovered.

That is, the present invention provides the following [1] to [6].
[1] A first step of adding water to incinerated bottom ash having a particle size of 10 mm or less;
A second step of dehydrating the incinerated bottom ash after adding water by centrifugation;
A third step of separating the dehydrated incineration bottom ash into heavy products and light products by gravity sorting, and recovering the light products as raw materials for cement;
The heavy products sorted in the third step are separated into non-magnetic substances and magnetic substances by magnetic separation, the non-magnetic substances are recovered as raw materials for non-ferrous refining, and the magnetic substances are recovered as raw materials for electric furnaces and blast furnaces. Equipped with a process,
How to dispose of bottom ash from incineration.
[2] The method for treating incinerated bottom ash according to [1] above, wherein in the first step, water is added to the incinerated bottom ash in an amount of 1 or more times by mass.
[3] The method for treating incinerated bottom ash according to [1] or [2] above, wherein in the second step, the incinerated bottom ash after hydration is screened and the sieve top ash is dehydrated by centrifugation.
[4] The method for treating incinerated bottom ash according to [3] above, wherein the sieve selection is performed with a sieve having a sieve mesh of 1 mm or less.
[5] Separating the slurry obtained by centrifuging the incinerated bottom ash after hydration into heavy products and light products by wet specific gravity sorting, recovering the heavy products as raw materials for non-ferrous refining, and recovering the light products as raw materials for cement. , The method for treating incinerated bottom ash according to any one of [1] to [4].
[6] The bottom ash obtained by sieving and separating the incinerated bottom ash after hydration is separated into heavy products and light products by wet specific gravity separation, and the heavy products are recovered as raw materials for nonferrous smelting, and the light products are recovered as raw materials for cement. , The method for treating incinerated bottom ash according to any one of [1] to [5].
[7] Processing of incineration bottom ash according to any one of [1] to [6] above, which has a preparatory step of sorting incineration bottom ash having a particle size of 10 mm or less from incineration bottom ash before the first step. Method.

ADVANTAGE OF THE INVENTION According to this invention, valuables can be efficiently sorted and collected from incineration bottom ash.

BRIEF DESCRIPTION OF THE DRAWINGS It is a flowchart which shows an example of the processing method of the incineration bottom ash of this invention.

The method for treating incinerated bottom ash of the present invention comprises a first step, a second step, a third step and a fourth step. Although each step will be described in detail below, an example of the method for treating incinerated bottom ash according to the present invention is shown in FIG.

[First step]
The first step is a step of adding water to incineration bottom ash having a particle size of 10 mm or less.
Incineration bottom ash is wet ash with a high moisture content and can have a moisture content as high as 18% to 35%. Therefore, when processing the incineration bottom ash, it is normal to remove moisture from the incineration bottom ash to improve handling properties, but the inventors dared to add water to the incineration bottom ash. also found that sorting of valuables contained in incinerated bottom ash becomes easy. That is, the wet incineration bottom ash may aggregate and become coarse due to the vibration of the device during physical separation. Coarse incineration bottom ash tends to cause clogging in the device, which leads to a decrease in processing efficiency, but water-added incineration bottom ash does not coarsen, so it is easy to supply to the processing device and is centrifuged. It was found that the separation of coarse and fine particles can be promoted by Here, in this specification, "incineration bottom ash" refers to incineration residue (bottom ash) that accumulates at the bottom of an incinerator when municipal garbage or industrial waste is incinerated. Therefore, the "incineration bottom ash" according to the present invention does not include incineration fly ash, which is dust in the exhaust gas at the time of incineration. Examples of industrial wastes include waste plastics such as waste automobiles, waste home appliances, vending machines, shredder dust from OA equipment, construction waste plastics, agricultural waste plastics, fishery waste plastics, and marine waste plastics. can.

First, the particle size of the incinerated bottom ash is adjusted, and the incinerated bottom ash used in the first step is prepared.
The particle size can be adjusted using, for example, a crusher or a classifier, or a combination thereof. Examples of crushers include jaw crushers, impact crushers, hammer crushers, roll crushers, and rotary crushers. In addition, in order to adjust the particle size of the incinerated bottom ash, the crusher is equipped with a screen with a desired sieve mesh. should be adjusted to Examples of classifiers include vibrating sieves such as ripple flow type and low head type, rotary sieves such as trommels, and wet classifiers such as spiral classifiers, and a desired sieve mesh may be used.

The particle size of the incinerated main ash after particle size adjustment is 10 mm or less, but from the viewpoint of preventing wear and damage inside the device, it is preferably 8 mm or less, more preferably 7 mm or less, and even more preferably 6 mm or less. Although the lower limit of the particle size of the incinerated bottom ash is not particularly limited, it is preferably 0.3 mm or more, more preferably 0.5 mm or more, and still more preferably 1 mm or more from the viewpoint of preventing clogging of the sieve mesh.

Next, water is added to the incinerated bottom ash whose particle size has been adjusted.
Any method can be adopted as long as it is a general method for adding water, and there is no particular limitation. A method of adding or spraying water to the incineration bottom ash and stirring it, and a method of adding or spraying water to the incineration bottom ash at the entrance of the conveyor, on the conveyor, or at the transfer point of transportation. In particular, when incinerator bottom ash and water are stirred in a stirring tank, it is possible to crush ash clumps and separate fine particles adhering to coarse particles, making it easy to separate coarse particles and fine particles in the centrifuge. becomes. The agitator is a device with a structure that rotates a horizontal cylindrical drum (container with a raking bar attached to the inside, rods and balls are inserted to promote disaggregation and separation of fine particles from coarse particles, or protrusions and In addition to equipment capable of continuously charging and discharging, such as a container with a structure in which a shaft with blades is inserted, a batch type mixer with 1 or 2 shafts used for stirring concrete is used. good too. Considering the effect of beating washing and the fact that continuous treatment is possible, it is more effective to use a horizontal cylindrical drum. The addition of water to the incinerated bottom ash may be performed intermittently or continuously.

Examples of water include tap water defined in JIS A 5303 Annex C and water other than tap water (eg, river water, lake water, well water, ground water, industrial water). Also, the water may be cooling water, room temperature water, or warm water, and is not particularly limited.

The amount of water added is preferably at least 1-fold by mass, more preferably at least 2-fold by mass, and even more preferably at least 3-fold by mass relative to the incinerated bottom ash. If the amount of water added to the incinerated bottom ash is too small, the fluidity of the incinerated bottom ash will decrease, and the handling property will tend to decrease due to clogging or the like in the next step. On the other hand, if the amount of water added is too large, not only does the work efficiency decrease, but also the cost increases. 10 times or less by mass is more preferable.

Moreover, in this step, the incinerated bottom ash after adding water may be sieved and the sieved portion may be subjected to the next step. As a result, separation of coarse particles and fine particles is further promoted by centrifugal separation, making it easier to sort and recover valuables from incinerated bottom ash.
For sieving, for example, the vibrating sieves, rotary sieves, and wet classifiers described above can be used, but are not limited to these.
The sieve mesh for sieve selection is preferably 0.5 to 1 mm, more preferably 0.3 to 0.5 mm, more preferably 0.3 mm from the viewpoint of further promoting separation of coarse particles and fine particles and preventing clogging. preferable.
In addition, it is preferable from the viewpoint of handling property that the sieved bottom ash after being filtered by the sieve is watered again to improve fluidity. The amount of water added may be selected appropriately as long as it has the same fluidity as when water is added to the incinerated bottom ash.

[Second step]
The second step is a step of dehydrating the incinerated bottom ash after the first step by centrifugation. Water and ash can be separated by centrifugation, but since fine ash containing a large amount of water (a large amount of Ca, S, and Cl) moves to the water side, Si, Al, Fe, Cu, Zn, etc. It is possible to recover the ash, which is mainly composed of coarse particles with a large amount of water, as a dehydrated product with a good water content. In addition, since the dehydrated product has a low water content of less than 18% and a small number of fine particles, it can be supplied to the next process without using thermal energy, etc., and valuable materials can be easily recovered. .

The centrifuge can be either a centrifugal sedimentation machine or a centrifugal dehydrator, but a centrifugal dehydrator, which can separate ash and water by passing water through the mesh of the screen, will collect more fine ash on the water side. Since it can be transferred, the moisture content of the ash can be further reduced. Moreover, when this step is performed a plurality of times, the water content reduction effect increases.

The centrifugal dehydrator includes types such as a cylindrical basket type and a conical basket type, but is not particularly limited.
Examples of filter media for the centrifugal dehydrator include filter cloth and screens. Among them, a screen with a pore size of 0.05 mm or more can be used for efficient dehydration. Examples of the material of the filter cloth include polypropylene and polyethylene, and examples of the material of the screen include stainless steel and Hastelloy.
The centrifugal force in centrifugal filtration is usually 100 to 2000G, preferably 200 to 1000G, more preferably 200 to 800G, from the viewpoint of dehydration efficiency.

The centrifugal sedimentation machine also has a straight body type, a decanter type, a disk type, and the like, but is not particularly limited.
The centrifugal force for centrifugal sedimentation is usually 500 to 4000G, preferably 1000 to 3000G, more preferably 1500 to 2500G, from the viewpoint of dehydration efficiency.

This step may be performed twice or more. In this case, this step may be performed again after adding water to the recovered dehydrated product in the same manner as in the first step. As a result, it is possible not only to further remove fine particles that could not be removed by one dehydration, but also to further reduce the water content.
Note that the slurry in this step may contain a large amount of fine particles. Therefore, in the present invention, it is possible to have a step of recovering solids from the slurry. For the dehydration treatment, for example, a centrifugal separator can be used, and a centrifugal sedimentation machine is preferred. The dehydration treatment may be performed multiple times.

After this step, the dehydrated matter is recovered from the centrifuge, and the recovered dehydrated matter can be subjected to a surface modification step in which air is blown to further reduce the water content. Further, after this step, instead of the surface modification step, or together with the surface modification step, the collected dehydrated matter may be sieved and separated into two or more grain groups, and each grain group may be subjected to the next step. can.

[Third step]
The third step is a step of separating the dehydrated incineration bottom ash into heavy products and light products by specific gravity sorting, and recovering the light products as raw materials for cement.
A known gravity sorter can be used as the gravity sorter, and either a dry type or a wet type can be used, but a dry table type gravity sorter is preferable, and an air table is more preferable.
In specific gravity sorting, for example, when an air table is used, the dehydrated incineration bottom ash supplied to the upper surface of the vibrating table is in a state of floating from the upper surface of the vibrating table due to the air flow passing through the vibrating table, and vibrates. Heavy products with high specific gravity move to the lower layer and light products with low specific gravity move to the upper layer due to the vibration imparted in the tilting direction of the table. It is received and moved diagonally upward, and the light product in the upper layer is pushed diagonally downward from the upper surface of the vibrating table without receiving the frictional force and vibration force, and the heavy product and the light product are discharged separately from the vibrating table. . The heavy products are then supplied to the next process, and the light products are recovered as raw materials for cement. As shown in the examples below, the light product is rich in calcium and can be reused as a raw material for cement.

In addition, in this process, when the incinerated bottom ash after adding water is sieved and the dehydrated matter obtained by dehydrating the sieve by centrifugation is gravity-selected, the water content of the dehydrated matter is sufficiently reduced, Heavy products can be easily recovered by processing with a gravity sorter. This heavy product is a grain group in which precious metals are particularly concentrated, and valuable metals such as Au, Ag, Cu, and Fe can be concentrated and recovered, and cement-repellent components such as Cr and Pb are also recovered in the heavy product. can. In addition, as described above, the dehydrated product has a sufficiently reduced water content, so it can be gravity sorted as it is, but it is better to dry the wet particle surfaces and then carry out the gravity sorting. Since it has an effect of suppressing stagnation on the deck of the specific gravity sorter, it may be treated with a blower on the conveyor or with a wind sorter.

[Fourth step]
In this step, the heavy products sorted in the third step are separated into non-magnetic substances and magnetic substances by magnetic separation, the non-magnetic substances are recovered as raw materials for non-ferrous refining, and the magnetic substances are recovered as raw materials for electric furnaces and blast furnaces. . This enables reuse of valuable metals.
A known magnetic force sorter can be used for the magnetic force sorting, and for example, any of a drum type, a pulley type, and a hanging type may be used, and there is no particular limitation.
In magnetic separation, for example, heavy products are supplied onto a drum with a permanent magnet placed inside, and magnetic substances contained in the heavy products are attracted to the surface of the drum, carried by the rotation of the drum, and discharged from the magnetic substance discharge port. be done. On the other hand, the non-magnetic substances contained in the heavy product separate and fall from the drum surface due to the rotation of the drum, and are discharged from the non-magnetic substance discharging port. The non-magnetic substances are recovered as raw materials for non-ferrous refining, and the magnetic substances are recovered as raw materials for electric furnaces and blast furnaces. As shown in the examples below, non-magnetic substances are rich in valuable metals such as Au, Ag, Cu, and Fe, so they can be reused as raw materials for non-ferrous refining. In addition, since magnetic deposits are rich in stainless steel, iron, etc., they can be reused as raw materials for electric furnaces and blast furnaces.

The surface magnetic flux density of the magnetic force sorter is preferably 700 to 10,000 gauss, more preferably 1,000 to 7,500 gauss, and still more preferably 1,500 to 5,000 gauss, from the viewpoint of promoting separation between non-magnetic and magnetic substances.

By treating the incineration bottom ash in this manner, valuables can be efficiently sorted and recovered from the incineration bottom ash.

Although the present invention has been described in detail based on the embodiments, the present invention is not limited to the above embodiments. Various modifications are possible for the present invention without departing from the gist thereof. For example, the under-sieves separated by sieving the dehydrated incineration bottom ash in the first step, and the slurry separated by centrifugation in the second step contain many fine particles derived from the incineration bottom ash. so you can collect them. More specifically, one or more selected from the under-sieves separated by sieving the incineration bottom ash after dehydration in the first step, and the slurry separated by centrifugation in the second step by wet specific gravity sorting. It can be separated into heavy products and light products, the heavy products recovered as non-ferrous smelting feedstock, and the light products recovered as cement raw material.

EXAMPLES The embodiments of the present invention will now be described more specifically with reference to Examples. However, the present invention is not limited to the following examples.

1. Analysis of Au, Ag, Fe, and Cr The analysis was performed according to the ore analysis method of JIS M 8100 to 8200.

2. Analysis of S, CaO, SiO ₂ , Al, Cu, Pb, and Cl Analyzed by the fundamental parameter method using a fluorescent X-ray analyzer (ZSX Primus II, manufactured by Rigaku).

Example 1
(Preparation process)
The incinerated bottom ash sorted by the existing equipment of the factory was sieved with a sieve having a sieve mesh of 25 mm. Next, the incinerated bottom ash under the sieve was sieved with a cylindrical vibrating sieve (KF-1000-3D, manufactured by Kowa Kogyosho Co., Ltd., screen 10 mm), and 50.0 kg of the sieved bottom ash was collected. The moisture content under the sieve was 25.0 mass%.
(First step)
150 L (three times the amount) of water was added to 50 kg of the sieved material, and the mixture was sufficiently stirred to obtain a uniform slurry.
(Second step)
The slurry was supplied to a centrifugal dehydrator (manufactured by Kotobuki Giken, N452K, screen 0.3 mm, centrifugal acceleration 300 G) for dehydration, and 41.5 kg of dehydrated matter was recovered. The water content of the dehydrated product was 16.5 mass%.
(Third step)
41.5 kg of dehydrated matter is supplied to a dry specific gravity sorter (SHB-4 manufactured by Harada Sangyo Co., Ltd.) and subjected to specific gravity sorting treatment, and the heavy product is separated into 2.5 kg. 0 kg and 39.5 kg of light products were recovered.
(Fourth step)
The heavy product collected in the third step is supplied to a drum-type magnetic sorter (manufactured by Nippon Magnetics, RENS-φ318 x 350 L, 3000 gauss) and magnetically sorted. 1.05 kg of kimono was collected.

Example 2
(First step)
The dehydrated product obtained by performing the preparation step, the first step, and the second step under the same conditions as in Example 1 was added with water again under the same conditions as in Example 1, and thoroughly stirred to obtain a uniform A slurry was obtained.
(Second step)
The slurry was dehydrated using a centrifugal dehydrator under the same conditions as in Example 1, and the dehydrated matter was recovered. The water content of the dehydrated product was 13.3 mass%.
(Third step)
The dehydrated matter was subjected to gravity sorting treatment using a dry gravity sorter under the same conditions as in Example 1, and heavy products and light products were recovered.
(Fourth step)
Heavy products were magnetically sorted using a drum-type magnetic sorter under the same conditions as in Example 1, and non-magnetic and magnetic substances were collected.

Example 3
(Preparation process)
The same operation as in Example 1 was performed on the under-sieves sieved with a sieve having a sieve opening of 25 mm, and the under-sieves were collected. The moisture content under the sieve was 25.0 mass%.
(First step)
The same operation as in Example 1 was performed for the under-sieve to obtain a uniform slurry.
(Second step)
The slurry was supplied to a centrifugal sedimentator (LCSS-M300-22 type, manufactured by CMS, centrifugal acceleration 2000 G) for dehydration, and the dehydrated matter was recovered. The water content of the dehydrated product was 17.8 mass%.
(Third step)
The dehydrated matter was subjected to gravity sorting treatment using a dry gravity sorter under the same conditions as in Example 1, and heavy products and light products were recovered.
(Fourth step)
Heavy products were magnetically sorted using a drum type magnetic sorter under the same conditions as in Example 1, and non-magnetic and magnetic substances were collected.

Example 4
(First step)
The dehydrated product obtained by performing the preparation step, the first step, and the second step under the same conditions as in Example 3 was added with water again under the same conditions as in Example 3, and thoroughly stirred to obtain a uniform A slurry was obtained. (Second step)
The slurry was dehydrated using a centrifugal settler under the same conditions as in Example 3, and the dehydrated matter was recovered. The water content of the dehydrated product was 16.9 mass%.
(Third step)
The dehydrated matter was subjected to gravity sorting treatment using a dry gravity sorter under the same conditions as in Example 1, and heavy products and light products were recovered.
(Fourth step)
Heavy products were magnetically sorted using a drum-type magnetic sorter under the same conditions as in Example 1, and non-magnetic and magnetic substances were recovered.

Example 5
(Preparation process)
The under-sieves were collected by the same operation as in Example 1, except that the under-sieves obtained by sieving with a sieve with a mesh size of 25 mm were sieved with a cylindrical vibrating sieve equipped with a screen of 6 mm. The moisture content under the sieve was 30.0 mass%.
(First step)
The same operation as in Example 1 was performed for the under-sieve to obtain a uniform slurry.
(Second step)
The slurry was supplied to a centrifugal dehydrator equipped with a screen of 0.4 mm, subjected to dehydration treatment at a centrifugal acceleration of 400 G, and dehydrated matter was recovered. The water content of the dehydrated product was 17.3 mass%.
(Third step)
The dehydrated matter was subjected to gravity sorting treatment using a dry gravity sorter under the same conditions as in Example 1, and heavy products and light products were recovered.
(Fourth step)
Heavy products were magnetically sorted using a drum-type magnetic sorter under the same conditions as in Example 1, and non-magnetic and magnetic substances were recovered.

Example 6
(Preparation process)
The under-sieves obtained by sieving with a sieve having a mesh size of 25 mm were sieved in the same manner as in Example 5, and the under-sieves were collected. The moisture content under the sieve was 30.0 mass%.
(First step)
A uniform slurry was obtained by the same operation as in Example 1, except that 50 L (one volume) of water was added to the under-sieve.
(Second step)
The slurry was supplied to a centrifugal dehydrator equipped with a screen of 0.4 mm, subjected to dehydration treatment at a centrifugal acceleration of 700 G, and dehydrated matter was recovered. The water content of the dehydrated product was 17.6 mass%.
(Third step)
The dehydrated matter was subjected to gravity sorting treatment using a dry gravity sorter under the same conditions as in Example 1, and heavy products and light products were recovered.
(Fourth step)
Heavy products were magnetically sorted using a drum-type magnetic sorter under the same conditions as in Example 1, and non-magnetic and magnetic substances were collected.

Example 7
(Preparation process)
The slurry obtained by performing the same operation as in Example 1 on the incinerated bottom ash under the sieve with a sieve opening of 25 mm was sieved with a sieve with a sieve opening of 0.3 mm, and the sieve top was collected. The moisture content on the sieve was 35.0 mass%.
(First step)
The same operation as in Example 6 was performed on the sieve to obtain a uniform slurry.
(Second step)
The slurry was supplied to a centrifugal dehydrator equipped with a screen of 0.3 mm, subjected to dehydration treatment at a centrifugal acceleration of 400 G, and dehydrated matter was recovered. The water content of the dehydrated product was 12.1 mass%.
(Third step)
The dehydrated matter was subjected to gravity sorting treatment using a dry gravity sorter under the same conditions as in Example 1, and heavy products and light products were recovered.
(Fourth step)
Heavy products were magnetically sorted using a drum type magnetic sorter under the same conditions as in Example 1, and non-magnetic and magnetic substances were collected.

Comparative example 1
(Preparation process)
The under-sieves were collected by the same operation as in Example 1, except that the under-sieves obtained by sieving with a sieve with a mesh size of 25 mm were sieved with a cylindrical vibrating sieve equipped with a screen of 15 mm. The moisture content under the sieve was 24.5 mass%.
(First step)
The same operation as in Example 1 was performed for the under-sieve to obtain a uniform slurry.
(Second step)
An attempt was made to dehydrate the slurry using a centrifugal dehydrator under the same conditions as in Example 1, but the dehydrated product could not be discharged, and subsequent implementation was abandoned.

Comparative example 2
(Preparation process)
The same operation as in Comparative Example 1 was performed on the under-sieves sieved with a sieve having a sieve opening of 25 mm, and the under-sieves were collected. The moisture content under the sieve was 24.5 mass%.
(First step)
The same operation as in Example 1 was performed for the under-sieve to obtain a uniform slurry.
(Second step)
An attempt was made to dehydrate the slurry using a centrifugal settler under the same conditions as in Example 3, but the dehydrated product could not be discharged, and subsequent implementation was abandoned.

Comparative example 3
(Preparation process)
The same operation as in Example 1 was performed on the under-sieves sieved with a sieve having a sieve opening of 25 mm, and the under-sieves were collected. The moisture content under the sieve was 25.0 mass%.
(First step)
A slurry was obtained by performing the same operation as in Example 1, except that 25 L (0.5 times the amount) of water was added to the under-sieve.
(Second step)
The slurry could not be supplied to the centrifugal dehydrator, and the subsequent implementation was abandoned.

Table 1 shows the treatment conditions in each example and comparative example. In addition, in each example and comparative example, light products (cement raw materials) obtained in the third step, and non-magnetic substances (non-ferrous refining raw materials) and magnetic substances (electric furnace / blast furnace raw materials) obtained in the fourth step ) are shown in Tables 2 and 3.

In Comparative Examples 1 and 2, there is a risk of damage to the centrifugal separator due to the generation of abnormal noise due to the bite of coarse particles, and the slurry cannot be discharged from the centrifugal dehydrator or centrifugal sedimentation machine. processing became difficult.
In Comparative Example 3, since the slurry had no fluidity, the slurry could not be supplied to the centrifugal dehydrator, making continuous treatment difficult.
In contrast, in Examples 1 to 7, since the slurry had fluidity, it was possible to supply the slurry to the centrifuge and to discharge the slurry. In addition, by subjecting the slurry after dehydration to specific gravity separation, it is possible to easily recover cement raw materials as light products. We were able to recover raw materials for electric furnaces and blast furnaces as kimonos.

Claims (7)

A first step of adding water to incinerated bottom ash having a particle size of 10 mm or less;
A second step of dehydrating the incinerated bottom ash after adding water by centrifugation;
A third step of separating the dehydrated incineration bottom ash into heavy products and light products by gravity sorting, and recovering the light products as raw materials for cement;
The heavy products sorted in the third step are separated into non-magnetic substances and magnetic substances by magnetic separation, the non-magnetic substances are recovered as raw materials for non-ferrous refining, and the magnetic substances are recovered as raw materials for electric furnaces and blast furnaces. Equipped with a process,
How to dispose of bottom ash from incineration. 2. The method for treating incinerated bottom ash according to claim 1, wherein in the first step, water is added to the incinerated bottom ash in an amount of 1 mass-fold or more. 3. The method for treating incinerated bottom ash according to claim 1 or 2, wherein in the second step, the incinerated bottom ash after hydration is sieved, and the sieved bottom ash is dehydrated by centrifugal separation. The method for treating incinerated bottom ash according to claim 3, wherein the sieve selection is performed with a sieve having a sieve mesh of 1 mm or less. A slurry obtained by separating incinerated bottom ash after adding water by centrifugation is separated into heavy products and light products by wet specific gravity sorting, and the heavy products are recovered as raw materials for non-ferrous refining, and the light products are recovered as raw materials for cement. The method for treating incinerated bottom ash according to any one of 1 to 4. The bottom ash obtained by sieving and separating the incinerated bottom ash after hydration is separated into heavy products and light products by wet specific gravity separation, the heavy products are recovered as raw materials for non-ferrous refining, and the light products are recovered as raw materials for cement. The method for treating incinerated bottom ash according to any one of 1 to 5. The method for treating incinerated bottom ash according to any one of claims 1 to 6, comprising a preparatory step of selecting incinerated bottom ash having a particle size of 10 mm or less from the incinerated bottom ash before the first step.

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