JP2659319B2 - Method and apparatus for recycling waste incineration residue - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention processes incineration residues discharged from a fluidized bed incinerator for municipal waste and collects and reuses it as iron scrap, non-ferrous metal scrap, concrete aggregate, crushed sand, and the like. The present invention relates to a processing method and a processing apparatus.

[0002]

2. Description of the Related Art According to "Japanese Waste 1991", edited by the Ministry of Health and Welfare, 73% of municipal solid waste is incinerated, and the total weight of this incinerated waste is 10%.
Assuming 0%, the weight of incineration residue after incineration is 14.5%. No further analysis of this 14.5% was published, but according to our research, this 14.5%
The breakdown of incineration residues is about 1-2% for metals and about 2 for non-metals.
Approximately 3%, fly ash and other about 10%.
Combined with the data of about 90,000 tons / day indicating the daily amount, the daily amount of non-metals incineration residues generated throughout Japan is estimated to be 1.8 to 2.7 thousand tons / day. Therefore, 1.8-2.7 every day
It is calculated that 1,000 tons of nonmetal residues are landfilled without being reused. However, the place where the above-mentioned landfill waste is landfilled, that is, the space of the final landfill disposal site is naturally limited, so that some municipalities will not be able to secure landfill space in the very near future if the current pace is maintained. Currently, incineration residues discharged from fluidized bed incinerators incinerated at high temperatures (hereinafter referred to as incineration residues) are treated by using a magnetic separator to separate and recover only iron, which is a magnetic material, and to remove the remaining non-ferrous metals. Non-metals that have passed through the magnetic separator and are mixed with iron are sent to landfills, but if they have some way to recover and use them, the life of final landfills scattered throughout the country can be extended. Will be. Therefore, the present inventors have focused on recovering and utilizing useful materials from incineration residues that have been conventionally disposed of in landfills, and as a result, the incineration residues from which iron has been removed show that the contents and the vast amount thereof. Considering that the use as civil engineering materials is the most suitable in view of the amount, further research has shown that if the following conditions can be satisfied, nonmetal residues can be used as substitutes for concrete aggregate and crushed sand. I found what I could do. Iron content is sufficiently removed Chloride content is reduced Harmless by alkali-silica reaction Non-ferrous metals are removed Particle shape is uniform

[0003]

Means for Solving the Problems The present inventors have described the above-mentioned.
As a result of diligent studies on a method for recovering nonmetal residues from incineration residues so as to satisfy the above conditions, the specific process of the present invention has been completed. That is, the present invention is a method for reusing non-metals from incineration residues discharged from a fluidized bed incinerator for waste, and (1) after recovering iron from the incineration residues by magnetic separation. A chloride removing step of removing fine particles containing a large amount of chloride from the obtained residue; (2) a residual iron removing step of removing residual iron from the residue by strong magnetic separation again; A non-ferrous metal removing step of removing non-ferrous metals from the residue using a voltage electric field or a strong induced current generated by rotating a strong magnet at a high speed, and (4) classifying the non-metals residue according to particle size. The present invention relates to a method for reusing waste incineration residues, which is characterized by performing a granulation step of processing particles into particles by repeating pulverization at least once, and a processing apparatus used in the method.

Hereinafter, the method for reusing waste incineration residues according to the present invention will be described in detail. In the processing method of the present invention, first, as a first step, generally performed,
After collecting iron from incineration residue by magnetic separation,
A chloride removal step of removing fine particles containing a large amount of chloride from the obtained residue is performed. As described above, this step is a step performed to achieve “reduction of chloride content” which is required as a condition when the nonmetal residue is used as a substitute for aggregate and crushed sand in concrete. . By the way, in general, chloride in fly ash generated during incineration of garbage is 6% in Cl amount.
As described above, the chloride in the incineration residue is 0.1 to 0.3 in Cl amount.
%. That is, most of the chloride evaporates and scatters while being contained in the fly ash, and a part thereof remains in the incineration residue. Further, the present inventors classified the incineration residue from which iron and non-ferrous metals had been removed in advance, measured the amount of chloride for each particle size, and examined the relationship between the particle size and the contained chloride. The results showed that most of the chloride contained in the incineration residue was contained in the fine-grained residue.

[0005]

[Table 1]

On the other hand, Ministry of Construction No. 142 issued by the Ministry of Construction (June 1986)
The special note on March 2) stated that "... chlorides contained in one cubic meter of concrete used for major structural strength of buildings such as reinforced concrete structures should be reduced to 0.30 kilograms or less. Is 0.30
In the case of using concrete exceeding the kilogram but not more than 0.60 kg, the allowable range of the chloride content in the concrete is indicated as the following (1).
ASS5 allows the content of chloride up to 0.1%, unless otherwise specified (JASS5 1990 edition). Therefore, the above "concrete used for the main part in structural strength"
In order to make the aggregate for use, the chloride content of the whole product should be 0.1
%, And the first step (chloride removal step) of the present invention is as described above, wherein most of the chloride contained in the incineration residue is contained in the fine particle residue. This is a process for removing the fine particles in the incineration residue to reduce the chloride in the non-metallic residue to 0.1% or less, based on the fact that the residue is in a non-metallic residue. More specifically, the present inventors remove the fine particles having a particle size of 0.3 mm or less from the received incineration residue by wind sorting or sieving, and further fine particles are subjected to the same method again in a particle processing step described later. It has already been confirmed that the above conditions (chloride content of 0.1% or less) can be maintained by removal by such methods, and it has been found that such a method can be used in the above chloride removal step.

Next, in the present invention, a residual iron removing step is performed as a second step. The residual iron is removed by subjecting the residue after the chloride removing step to a strong magnetic separator again to remove the residual iron. This is the step of performing Here, `` again '' means that, as described above, a fluidized bed incinerator plant is usually provided with a magnetic separator for separating and recovering iron from the residue. This is because the function is not sufficiently fulfilled, and a large amount of iron remains in the residual residue subjected to the magnetic separator. In addition, as described above, this step is performed to achieve “sufficient removal of iron”, which is required as a condition for substituting nonmetallic residues for concrete aggregate and crushed sand. The reason why such conditions are required is that if iron remains in the concrete aggregate, this iron may gradually rust and color the surface of the concrete product. . Therefore, the second aspect of the present invention
In the process (removal of residual iron), a magnetic separator of about 2,000 gauss is used instead of the conventional magnetic separator of about 1,000 gauss, and the magnetic force is applied to the rear pulley of the conveyor that carries the incineration residue, for example. By arranging the magnetic force portion of the sorting machine, the distance between the magnetic force portion and the non-sorted object is made the shortest distance, and a device is devised so as to maintain a sufficient proximity time, thereby completely removing iron.

Next, in the present invention, a non-ferrous metal removing step is performed as a third step. This step uses a high voltage electric field or a strong induced current generated by rotating a strong magnet at a high speed to make use of the residual iron content. From the residue obtained after the removal step,
This is a step of removing non-ferrous metals. This step, as described above, is a step performed in order to achieve "removal of non-ferrous metals", which is required as a condition when non-metal residues are used as substitutes for aggregate and crushed sand in concrete. These conditions are required because nonferrous metals can adversely affect concrete, and some of these nonferrous metals are relatively expensive and reusable, such as copper and brass. This is because many are high.
In general, nonferrous metals in incineration residues often contain various small parts.For example, relatively large ones such as kettles and pipes can be easily removed by sieving, but fine parts are difficult to visually remove with the naked eye. is there. Therefore, in the treatment of incineration residues, there are very few cases in which the operation of separating non-metals and non-ferrous metals is performed industrially. As one method of separating non-ferrous metals from non-metals, there is also an attempt to add metal particles to heavy oil and separate them with a specific gravity difference.
As a method of treating incineration residues, an operation of washing and removing oil is indispensable, which is complicated and not economical. Therefore, in the incineration residue treatment of the present invention, a non-ferrous metal separation and recovery method using a high voltage region or a non-ferrous metal separation and recovery method using an induced current is employed. First, the former method uses a 50,000 to 100,000 volt DC power supply to provide a high piezoelectric area of 5 to 10 m in height,
In addition, a method is provided in which a discharge wire is provided above and corona discharge is performed to drop an object to be separated from above into a high voltage region. The latter method has been used to sort aluminum cans. However, the magnetic force is insufficient (about 1,000 gauss) if it is diverted as it is, so the magnetic force filling the drum is increased to 2000-3000 gauss. At the same time, the number of poles is usually doubled or increased from 16 poles, and the number of revolutions usually increased from 1500 to 1800 rpm to about 3000 rpm. We have:
As a result of repeated experiments on non-ferrous metal removal with various improvements, the separation test of the incineration residue from which iron was completely removed showed that when the non-ferrous metal weight ratio in the sample was 50.5%, the separation rate was 75 to 85%, When the weight ratio of non-ferrous metals in the sample was 100%, a separation rate of 83 to 87% was obtained. Here, non-ferrous metals that cannot be separated are mainly bolts and nuts made of stainless steel, thick castings, and tangled copper wires, which cannot be separated well by the high-voltage electric field method or the induced current method.
However, since they have a relatively large shape, it has been confirmed that they can be removed in the step of separating particles according to particle size after the pulverization step described later. When the amount of the residue to be treated was about 10 tons / day, it was also confirmed that the separation method using the induced current was more economical in plant design.

Next, in the present invention, a granulation step is performed as a fourth step following the third step. In this step, the residue obtained after the completion of the non-ferrous metal removal step is classified and pulverized according to particle size. A step in which the flat shard-like residue is granulated by removing the residue once or more times, or the corners of the residue are deleted, and the residue is processed into particles having a particle size that can be used as aggregate for concrete and crushed sand. It is.
As described above, this step is performed to ensure that “the particle shape is uniform” required as a condition when the nonmetal residue is used as a substitute for aggregate and crushed sand in concrete. It is a process. More specifically, first, a nonmetal residue is sieved, and a residue of 0.3 mm or less is collected from the residue.
It was discarded for the purpose of chloride removal as described above. Next, crushing and elimination are required. For plate-shaped glass pieces and ceramic pieces, those having a surface length several times the plate thickness require crushing. The reason for this is that fragments that have too large a flat surface (including a curved surface) with respect to the plate thickness entrain air when kneading with cement. Therefore, the plate-like fragments must be crushed to a surface length of about 2 to 3 times the plate thickness. In addition, simply crushing glass or ceramics leaves ridges on the fractured surface and is dangerous if touched by humans. It is important to note that many lines are required on the smooth glass surface and on the glaze of ceramics to improve the adhesion to the cement. In order to satisfy the above-mentioned requirements for the shape of ready-mixed concrete manufacturers, crushers used in quarries and the like are merely crushed, and are not cut or deleted, which is insufficient. Therefore, the present inventors focused on the use of a rod mill or a ball mill, which holds a material to be ground in a rotating body for a certain period of time as a pulverizer and aims to remove the material due to abrasion between the objects to be ground, and prototyped a test machine using a rod mill. The experimental tests were repeated with different rod dimensions and retention times in the drum. Most of glass and ceramic pieces are 2-3mm thick
Therefore, the data as shown in FIG. 2 was obtained by analyzing the data of an experimental test using a flat surface (including a curved surface) length of 6 mm as a reference and a clogged particle diameter of 6 mm as a reference. . From the results in FIG. 2, particles of 6 mm or more decrease with time, while particles of 2 to 6 mm increase with time, and the rate of increase of particles of 2 mm or less is the rate of increase of particles of 2 to 6 mm diameter. It turns out that it is smaller than. Also, the change in the degree of pulverization due to the thickness of the rod was also determined. From this result, in the pulverization process, two systems, larger and smaller, were divided into coarse particles of 6 mm or more based on a particle size of about 6 mm in diameter. It is better to use a heavy rod to give a stronger crushing force and a lighter rod for the purpose of abrasion to prevent powdering of fine particles than to crush it. Was confirmed.

As described above, by following a series of operations relating to the method for treating incineration residues of the present embodiment, the "iron content" required as a condition for substituting nonmetal residues for aggregate and crushed sand in concrete is obtained. , That the non-ferrous metals are removed, that the chloride content is reduced, and that the particle size and shape are uniform. Will be satisfied. As a result, if the non-ferrous metal residue treated by the method for treating incineration residue of the present example satisfies the last condition, which is “harmless by the alkali silica reaction (hereinafter abbreviated as ASR)”, Non-metal residues can be used as substitutes for concrete aggregate and crushed sand.

ASR is a phenomenon in which a product produced by a reaction between silica having reactivity in an aggregate and an alkali contained in concrete absorbs water and expands to cause cracks or the like in the concrete. JIS A5308
Judgment of the reactivity by the reaction test method (chemical method) described above is that “when the amount of dissolved silica (Sc) is 10 mmol / L or more and the amount of reduced alkali concentration (Rc) is less than 700 mmol / L,
When the amount of dissolved silica (Sc) is equal to or greater than the alkali concentration decrease (Rc), the aggregate is determined to be harmless, and the other aggregates are determined to be harmless. ". Therefore, the present inventors classified non-metal residues obtained according to the above-described method for treating incineration residues of this example, and classified AS
When the R test was performed, the results shown in Table 2 below were obtained.

[0012]

[Table 2]

As is clear from Table 2 above, the residues of both samples A and B could be determined to be harmless.
As a result of repeating this experiment many times, it was clarified that the values of Rc and Sc varied, and thus it was impossible to judge whether the particle diameter was harmless or not harmless in the ASR test.
In addition, it should be taken into account that nonmetal components in the incineration residue differ depending on the region where the incineration residue originates, in other words, the municipalities where the base waste is generated. Therefore,
The present inventors took out three main components (porcelain, stone, and glass) from the nonmetal residue and performed an ASR test on these components. The results shown in Table 3 below were obtained.

[0014]

[Table 3]

From the results shown in Table 3 above, it is clear that the determination of the ASR test is harmless or not harmless, because the content of glass is greatly involved.
From the value, it was found that the maximum allowable content of the glass component was 65%. Based on the above results, the present inventors collected various types (regions) of incineration residues, and investigated the glass components in the nonmetal components. As a result, the maximum amount of the glass components was 61%. And most of them were found to be in the 40-50% range. Therefore, it is clear that the nonmetallic components in the incineration residue used in the treatment method of the present invention satisfy the condition that “the judgment in the ASR test is harmless”, and thus the concrete aggregate and It can be said that it can be sufficiently used as a substitute for crushed sand.

[0016]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a schematic diagram showing an example of the incineration residue treatment device of the present invention. The processing apparatus of the present embodiment includes a carry-in conveyor 1 that conveys the incineration residue to each of the processing apparatuses described below, a fine particle separator 2 disposed at the forefront of the carry-in conveyor 1, and a fine particle separator 2 disposed at a subsequent stage. A magnetic force separator 3, a non-ferrous metal separator 4 disposed downstream of the magnetic force separator 3, and a granulating device X disposed downstream of the non-ferrous metal separator 4. Further, the particle separator 2, the magnetic separator 3, and the non-ferrous metal separator 4 are connected to a particle hopper 6, an iron scrap hopper 7, and a non-ferrous metal hopper 8, respectively. The fine particle separator 2 is a device for performing a chloride removing step of removing fine particles containing a large amount of chloride from the incineration residue as described above. For example, the fine particle separator 2 is placed on a sieve having a predetermined mesh, and then the vibration generator is used. A vibration separator or the like of a type that vibrates at a pressure is used. The magnetic force sorter 3 is a device that removes residual iron by applying a strong magnetic force again to incineration residues that have already been subjected to iron removal by a normal magnetic force sorter before being introduced into the conveyor 1. This is an apparatus for performing a residual iron removing step. This magnetic force sorter 3 uses a magnetic drum having a magnetic force portion that generates a magnetic force (2000 to 3000 gauss) stronger than the magnetic force (1000 gauss) used in a normal magnetic force sorter,
Also, instead of placing the magnet drum of the sorting machine in the middle of the chute as in the past and dropping the sorting object from above and separating it left and right, the magnet drum is incorporated into the pulley of the belt conveyor to reduce the thickness of the belt. This is to increase the sorting ability by keeping the contact with the sorting object as thin as possible and keeping it in close contact for a longer time. After removing irons by this, the remainder enters the next non-ferrous metal separator 4. The non-ferrous metal separator 4 is a device that literally separates and collects metals other than iron (for example, aluminum, etc.) from the incineration residue. The non-ferrous metal is separated by either a method of dropping or a method of separating a good conductor using an induced current generated by rotating a strong magnetic material at a high speed. The above-mentioned apparatus for separating fine particles, ferrous metals and non-ferrous metals is used during the operation time of the incinerator, for example, 16 hours / day or 24 hours.
Drive continuously for hours / days. This is because a smaller amount can be separated and the separation accuracy is higher. The residue that has passed through these certain removal devices is stored in the intermediate hopper 5. The reason for providing this intermediate hopper is that, in the subsequent granulating apparatus X, it is better to continuously process a certain amount of material, the efficiency and results of pulverization / deletion are better, and the operation monitoring and dispensing of heavy machinery must be performed daily. Because you can concentrate inside.

As shown in FIG. 1, the granulating apparatus X comprises four sieves A, B, C, D (9, 11, 12, 15), a coarse crusher 10 and a fine crusher 14. I have. This coarse crusher
The crusher 10 and the fine crusher 14 are each of a drum type rod mill type, and the thickness of the iron rod to be charged is determined according to the necessity of crushing, but is in the range of 20 to 50 mmφ. Several lifting flights parallel to the drum axis are provided on the inner surface of the drum. The material to be ground is continuously charged, but 10 to 20
The powder is kept in the drum for one minute, and the crushing by the iron bar and the deletion by the kneading action of the flight are performed simultaneously in parallel, so that the uniformity of the shape (granulation) is efficiently achieved. To minimize the amount of pulverization by pulverization, the inside of the coarse pulverizer is divided into two stages in series in the flow direction, with a thick iron bar at the front and a thinner bar at the rear. In the meantime, the yield of the product as the aggregate is increased.
On the other hand, the fine crusher aimed to finish the product by removing it, made the iron bar thinner, and made the residence time longer than that of the coarse crusher. In addition, in both the coarse and fine crushers, the dimensions of the rods can be changed arbitrarily, the rotation speed of the drum is made variable, and the residence time of the incineration residue can be set freely. Therefore, it is possible to flexibly cope with the qualitative fluctuation of the residue due to the fluctuation of the load of the incinerator and the regional difference and seasonal difference of the city where the incinerator is installed. The non-metal residue that has passed through the non-ferrous metal separator 4 is first divided into two sieves A (5). The fine residual particles that have passed through the sieve A are provided at the subsequent stage of the sieve A, and are introduced into a fine pulverizer 14 for the purpose of giving the particles roundness rather than pulverization. Coarse residual particles that do not pass through the eye are also introduced into a coarse crusher 10 disposed downstream of the sieve A to be pulverized, and sieved by the sieve B. At this time, the fine particles that have passed through the sieve B are further fed into the fine crusher 14, and those that have not passed through the sieve B are sieved by the sieve C, and the particles that have passed through the sieve C are again sent to the coarse crusher 10. It is designed to be refluxed. Those that did not pass through the sieve C are pieces of ceramics that have become spherical and are not easily crushed any more, or massive non-ferrous metal pieces or linear non-ferrous metals that have passed through the non-ferrous metal separator 4. They are,
Dispose of it as an unsuitable component. On the other hand, the material processed by the fine crusher 14 to a good granular shape without a corner portion is divided into fine aggregate and coarse aggregate by a sieve D with a difference in particle size.
It is divided into hoppers 16 and 17 as final products. The sieves of the sieves A to D are 5 to 6
It is selected based on mm. This is based on the judgment that most glass pieces and ceramic pieces have a thickness of 2 to 3 mm, and the aggregate has a surface length of 2 to 3 times the plate thickness. However, the thicker ones are less likely to be crushed, and even if the surface length is somewhat longer, they are almost granular. Therefore, the upper limit of the sieve of the sieve C is set to about 15 mm.

[0018]

As described above, according to the method for reusing waste incineration residues of the present invention having the above-mentioned structure, various useful components, in particular, from the incineration residues currently disposed in landfills, Non-metallic residues, which account for 70-80% of the residues and can be used as aggregate for concrete, can be efficiently recovered, and as a result, the life of landfills can be extended by reusing the recovered components and reducing the volume of landfills And reduction of waste disposal costs.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an incineration residue treatment device of the present invention.

FIG. 2 is a graph showing data of residue treatment by a rod mill in the granulation step of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conveyor for carrying in residue 2 ... Particle separator 3 ... Magnetic separator 4 ... Non-ferrous metal separator 5 ... Intermediate hopper 6 ... Particle hopper 7 ... Iron scrap hopper 8 ... Non-ferrous metal hopper X ... Granulation device 9 ... Sieve A10 ... Coarse pulverizer 11 ... sieve B 12 ... sieve C 13 ... defective raw material hopper 14 ... fine pulverizer 15 ... sieve D 16 ... fine product hopper 17 ... coarse product hopper

Claims (2)

(57) [Claims] 1. A method for recycling non-metals from incineration residues discharged from a fluidized bed incinerator for waste, comprising: (1) recovering iron from incineration residues by magnetic separation; A chloride removing step of removing fine particles containing a large amount of chloride from the obtained residue; (2) a residual iron removing step of removing residual iron from the residue by strong magnetic separation again; A non-ferrous metal removing step of removing non-ferrous metals from the residue using a voltage electric field or a strong induced current generated by rotating a strong magnet at a high speed, and (4) classifying the non-metals residue according to particle size. Repeat crushing once or more,
And a granulation step of processing the waste into incineration. 2. Discharged from a waste fluidized bed incinerator ,
Equipment to treat incineration residues collected by magnetic separation of iron
A fine particle separator (2) for removing fine particles containing chloride from the waste fluidized incineration residue , and the waste fluid separating device disposed downstream of the fine particle separator (2).
A strong magnetic separation device (3) for separating and removing iron from the incineration residue by using a strong magnetic force , and a non-ferrous metal is removed from the waste fluidized incineration residue disposed downstream of the strong magnetic separation device (3). Non-ferrous metal separator
(4) Classifying means arranged at the subsequent stage of the non-ferrous metal separator (4), which classifies the non-metals residue obtained by removing iron, chloride fine particles and non-ferrous metal from the incineration residue by particle size, and rotating. A drum-type pulverizer having a drum having a variable number and residence time; and a granulating device (X) for appropriately pulverizing the residue classified by the classification means and uniformly forming the residue into particles. A waste incineration residue treatment device characterized by the above-mentioned.