JP5172196B2 - Incineration ash particle sorting method - Google Patents

Description

  The present invention relates to a method for selecting incinerated ash particles and efficiently selecting harmful substances contained in the incinerated ash.

  At present, most municipal waste incineration ash is landfilled. However, effective use of incinerated ash is being studied and promoted from the viewpoint of landfill sites and the establishment of a recycling society. As one of the usage methods, studies are being made to use it for civil engineering materials.

  However, since incinerated ash contains a lot of harmful substances, especially lead, it is necessary to separate and remove lead in order to use it for civil engineering materials. As a method for measuring harmful substances contained in incinerated ash, Ministry of the Environment Notification No. 18 (elution amount) and Ministry of the Environment Notification No. 19 (content) specified in the Soil Contamination Countermeasures Law are applied and measured. It is necessary to observe the standard regarding the amount of Pb.

  At present, as a method for reducing lead in incineration ash, incineration ash treatment by melting slag, burning cement or the like is known. Detoxification by burning incinerated ash is aimed at detoxification of dioxins and removal and stabilization of heavy metals. As stipulated in the Law Enforcement Regulations on Waste Disposal and Cleaning, 1000 It is necessary to process at a temperature of ℃ or higher. For example, a technique is known in which silica sand and coke are added to incineration ash and fly ash, and the mixture is baked at 1000 to 1300 ° C. to make it harmless (Patent Document 1).

  However, these treatment methods require high temperature treatment of 1000 ° C. to 1600 ° C. or more, and enormous energy is required. And since a lot of carbon dioxide used as a warming gas may be discharged and a high technique is required for operation of the apparatus, a simple incineration ash treatment technique with low energy consumption is eagerly desired.

Japanese Patent Laid-Open No. 10-67547

  Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and the purpose thereof is to select the incineration ash based on the difference in specific gravity, so that the specific gravity of the incineration ash on the heavy specific gravity side An object of the present invention is to provide a method for sorting incinerated ash particles that can reduce the content of harmful substances in the incinerated ash on the light side. In particular, although lead is described, the present invention can be applied to a substance having a large specific gravity such as cadmium.

The above-mentioned subject is achieved by the invention described in each claim. That is, an incineration ash particle selection method for selecting particles constituting incineration ash, wherein a removal step of removing magnetic substances and / or aluminum from the incineration ash, and a particle size difference of the incineration ash after the removal step A particle size selection step for selecting incinerated ash particles using the difference in specific gravity of the incineration ash with respect to the incineration ash having a smaller particle size selected in the particle size selection step after the particle size selection step anda gravity separation step of selecting the ash particles by using, the particle径選specific process the particle size is larger side of incineration ash sorted by using as a material, which is selected by said gravity separation step and features that you use a lighter specific gravity side of incinerator ash as a material.

  According to this configuration, by selecting the incineration ash based on the difference in specific gravity, the lead content of the incineration ash having the lighter specific gravity becomes lower than the incineration ash having the higher specific gravity. Since the incinerated ash on the lighter side of the specific gravity has a low lead content, it can be used for civil engineering materials and the like without performing molten slag treatment or firing treatment. Incineration ash on the heavy specific gravity side has a high lead content, so it is necessary to carry out molten slag treatment and firing treatment. However, compared to conventional methods, it is no longer necessary to treat the entire amount of incineration ash. Reduces carbon gas emissions.

Further, as an example of a preferred embodiment of the present invention, the particle size selection step is selected by a first particle size selection step of selecting the incinerated ash after the removal step and the first particle size selection step. A second particle size sorting step for sorting the incineration ash on the side having a smaller particle size,
In the specific gravity sorting step, the incineration ash having a smaller particle size selected in the second particle size sorting step is selected, and the incineration ash having a larger particle size selected in the first particle size sorting step is used as a material. Use as
Characterized to have access to light specific gravity side ash which is selected by said gravity separation step as materials. As another embodiment, the particle size selection step includes a first particle size selection step of selecting the incinerated ash after the removal step, and a particle size selected in the first particle size selection step is small. A second particle size selection step for selecting the incineration ash on the side, and a third particle size selection step for selecting the incineration ash on the side having a smaller particle size selected in the second particle size selection step, The specific gravity sorting step includes a first specific gravity sorting step for sorting the incinerated ash having a smaller particle size selected in the second particle size sorting step, and a smaller particle size selected in the third particle size sorting step. It has a second gravity separation step of selecting ash, and the ash of the first grain径選specific process the particle size which is selected by the larger side used as materials, sorted by the first gravity separation step using a light specific gravity side of ash that is as materials, incineration of the second gravity sorted in sorting step the lighter specific gravity side Use ash as material .

  According to this configuration, the specific gravity selection step can be performed after the particle size selection step. In the particle selection, the specific gravity selection may be performed on the incinerated ash having a previously selected particle size (smaller particle size). There is no need to set the processing capacity higher than necessary. This is because the particle size sorting process can be performed with simple equipment and in a short time compared to the specific gravity sorting process. In the incinerated ash, particles having a large particle size are silicon (for example, glass or the like), and in most cases, lead is not contained, or even if it is contained, the amount is small.

  In the following, first, the background to the idea of the technical idea of the present invention will be described. First, there is a study of classifying incinerated ash with a sieve and measuring the amount of hydrochloric acid extracted from the lead contained in each fraction ("Behavior of heavy metals in municipal waste incinerated ash during firing, I. Characterization and firing by particle size" Effect ", Proceedings of the 15th Annual Meeting of the Waste Science Society, pp. 751-753, 2004). According to this report, it has been reported that the smaller the particle size, the greater the amount of lead extracted with hydrochloric acid.

  In addition, after classifying with a sieve, the metal element content of each fraction (quantified by completely dissolving ash with aqua regia) is measured, and there is research on their distribution behavior (“size of municipal solid waste incineration ash” Separate Dissolution Test "Proceedings of the 12th Waste Society Research Presentation, 860-862, 2001). According to this, it is reported that the particle size of incinerated ash and the content of lead contained therein are not regular.

  Based on the above research results, when sorting using the incineration ash particle size difference, the lead contained in the incineration ash may be separated, but it may not be possible. Incineration ash used for civil engineering materials It is considered that sorting for reducing the lead content is difficult only by particle size sorting.

  Based on the above considerations, the present inventor came up with the present invention, and the essence is to use the difference in physical properties of the incineration ash in order to select the incineration ash with a low lead content, that is, The first method is a method of selecting incineration ash with a low lead content using the specific gravity difference, and the second method is to classify the incineration ash according to the particle size, This is a method for selecting incineration ash having a small particle size based on the difference in specific gravity.

(Particle size selection)
This is a step of classifying incinerated ash according to the particle size. The range of the particle size can be appropriately set according to the properties of the incineration ash. As the particle size selection means, there are known classification means, and for example, a vibration sieve machine, a wind-type sieve machine, a dry centrifugal separator, a wet centrifugal separator or the like can be used.

(Specific gravity selection)
This is a process of separating the incineration ash by specific gravity. Specific gravity selection methods include a wet specific gravity separation method and a dry specific gravity separation method. Examples of the wet specific gravity separation method and apparatus include an apparatus (floating / sinking separator) for injecting incinerated ash into water and dividing it into an upper layer part and a lower layer part, a wet cyclone, and the like. As the dry specific gravity separator, a wind separator, a cyclone or the like can be used. In the case of the wet specific gravity separation method, a drying process may be necessary as appropriate depending on the requirements of the subsequent steps.

(Embodiment 1)
The incinerated ash having the particle size distribution shown in FIG. 1 was selected with a sieve. Incinerated ash with a fraction of 2.00 to 3.35 mm was collected and subjected to wet specific gravity separation. The specific gravity separation operation was performed by filling the cylinder with water, injecting incineration ash from the upper part of the cylinder, and dividing the incineration ash deposited on the bottom part into an upper layer part and a lower layer part.

  About the incinerated ash of this upper layer part and lower layer part, the test prescribed | regulated to Ministry of the Environment notification No. 19 was done, and lead content was measured.

  As a result, the lead content in the lower layer was 470 mg / kg, whereas the upper layer was 170 mg / kg. From this, it was confirmed that ash (lower layer part) with high lead content and low ash (upper layer part) can be separated by carrying out specific gravity separation.

  In addition, the incinerated ash with a fraction of 4.75 to 6.73 mm was collected, tested in accordance with the Ministry of the Environment Notification No. 19, and the lead content was measured to be 70 mg / kg. The environmental standard value stipulated in 1) was 150 mg / kg or less.

  From previous research, it was thought that separation of lead was insufficient with only particle size selection. However, the combination of particle size selection and specific gravity selection ensures reliable separation of ash with high lead content and low ash. It was confirmed that it could be done.

(Embodiment 2)
Hereinafter, another embodiment of the method for sorting incinerated ash particles will be described.

  As shown in FIG. 2, incineration ash is discharged from the incinerator (# 1). The discharged incinerated ash is subjected to a magnetic separator and an aluminum separator in the next step to remove magnetic substances and the like (# 2). Next, in the particle size selection step, the incinerated ash is classified with a vibrating screener having an opening of 5 to 150 mm (# 3). Here, the incineration ash of the sieve pass contains a large amount of incineration ash with a large amount of lead hydrochloric acid extracted. On the other hand, most of the incinerated ash on the sieve (does not pass) has a small amount of lead hydrochloric acid extracted, so it can be used as it is for civil engineering materials (underground roadbed aggregate, asphalt mixing aggregate, etc.). The amount of incinerated ash on the sieve is, for example, 0 to 40% by weight with the incinerated ash after the previous step being 100% by weight (this depends on the properties of the incinerated ash and the starting material). The amount of lead hydrochloric acid extracted is the lead content measured by the measurement method shown in Ministry of the Environment Notification No. 19.

  On the other hand, the sieving (passed) incineration ash is subjected to specific gravity sorting by a specific gravity sorter (# 4). By the specific gravity selection here, incineration ash with a light specific gravity is often used for civil engineering materials (underground roadbed aggregates, aggregates for asphalt mixing, etc.) because there are many extracts of lead hydrochloric acid extracted. The amount of incinerated ash having a light specific gravity is, for example, 10 to 40% by weight, with the total amount of incinerated ash selected by specific gravity being 100% by weight.

  On the other hand, incineration ash with heavy specific gravity selected by specific gravity sorting contains a lot of incineration ash with a large amount of lead hydrochloric acid extracted, so it is sent to a melting furnace or a baking furnace, where it is melted or fired, respectively. The amount of lead hydrochloric acid extracted is reduced (# 5).

  In FIG. 3, the particle size selection process is performed in two stages in the configuration of FIG. The particle size selection in the first stage is the same as that in FIG. 2, but in the subsequent process, classification is performed with a vibrating screen machine having an opening of 2 to 10 mm as the second stage (# 31). The incinerated ash on the sieve (does not pass) is subjected to specific gravity sorting by a specific gravity sorter (# 32). Since the selected incineration ash with a light specific gravity is often low in the amount of lead hydrochloric acid extracted, it can be used as it is for civil engineering materials (underground roadbed aggregate, aggregate for asphalt mixing, etc.). The amount of incinerated ash having a light specific gravity is, for example, 10 to 40% by weight, with the total amount of incinerated ash selected by specific gravity being 100% by weight.

  On the other hand, the incineration ash under the sieve contains a lot of incineration ash with a large amount of lead hydrochloric acid extracted, so it is sent to the melting furnace or firing furnace, where it is melted or fired, respectively, and extracted with lead hydrochloric acid. The amount is reduced (# 5).

  FIG. 4 further includes a third stage particle size selection step in the configuration of FIG. As a third stage, classification processing is performed with a vibrating sieve having an opening of 1 to 5 mm (# 41). The incinerated ash on the sieve (does not pass) is subjected to specific gravity sorting by a specific gravity sorter (# 42). Since the selected incineration ash with a light specific gravity is often low in the amount of lead hydrochloric acid extracted, it can be used as it is for civil engineering materials (underground roadbed aggregate, aggregate for asphalt mixing, etc.). The amount of incinerated ash having a light specific gravity is, for example, 5 to 40% by weight, with the total amount of incinerated ash selected by specific gravity being 100% by weight.

  On the other hand, since the incinerated ash under the sieve is contained in a large amount of incinerated ash with a large amount of lead hydrochloric acid extracted, it cannot be used as it is for civil engineering materials, so it is sent to a melting furnace or a firing furnace, respectively. A baking treatment is performed, and the lead hydrochloric acid extraction amount is reduced (# 5).

  2, 3 and 4 illustrate that the particle size selection step and the specific gravity selection step can be provided in other stages. And providing these processes in multiple stages in this way can be selected as appropriate according to the particle size distribution and properties of the incinerated ash.

Figure showing the particle size distribution of incineration ash The figure which shows an example of embodiment The figure which shows an example of embodiment The figure which shows an example of embodiment

Claims (3)

An incineration ash particle sorting method for sorting particles constituting incineration ash,
A removal step of removing magnetic substances and / or aluminum from the incinerated ash;
After the removal step, a particle size selection step of selecting the incineration ash particles using the particle size difference of the incineration ash,
After the particle size selection step, for the incineration ash with a smaller particle size selected in the particle size selection step, a specific gravity selection step of selecting the incineration ash particles using the specific gravity difference of the incineration ash, Have
Using the particle径選specific particle size which is selected in step a large side of the incineration ash as a material,
Using incineration ash of the gravity separation step is sorted lighter specific gravity side as it materials, does not use the incinerated ash of the gravity separation step is sorted heavier specific gravity side as materials, or of the heavier gravity side ash A method for sorting incinerated ash particles, characterized by subjecting to a melting treatment or firing treatment . The particle size selection step includes a first particle size selection step of selecting the incineration ash after the removal step, and a first particle size selection step of selecting the incineration ash having a smaller particle size selected in the first particle size selection step. 2 particle size selection process,
In the specific gravity sorting step, the incinerated ash on the side having a smaller particle size sorted in the second particle size sorting step is sorted,
Using the incinerated ash on the side of the larger particle size selected in the first particle size selection step as a material,
Using incineration ash of the gravity separation step is sorted lighter specific gravity side as it materials, does not use the incinerated ash of the gravity separation step is sorted heavier specific gravity side as materials, or of the heavier gravity side ash The method for sorting incinerated ash particles according to claim 1, wherein the ash is melt-processed or fired . The particle size selection step includes a first particle size selection step of selecting the incineration ash after the removal step, and a first particle size selection step of selecting the incineration ash having a smaller particle size selected in the first particle size selection step. A second particle size selection step, and a third particle size selection step for selecting the incinerated ash having a smaller particle size selected in the second particle size selection step,
In the specific gravity sorting step, the first specific gravity sorting step of sorting the incinerated ash having a smaller particle size sorted in the second particle size sorting step and the small particle size sorted in the third particle size sorting step. A second specific gravity sorting step of sorting the incineration ash on the side,
Using the incinerated ash on the larger particle size side selected in the first particle size selection step as a material ,
The lighter specific gravity side of ash that has been sorted by the first gravity separation step as it is used as a material, does not utilize the heavy gravity side of ash that has been sorted by the first gravity separation step as materials, or the heavy gravity The incineration ash on the side is melted or fired,
The lighter specific gravity side of ash that has been sorted by the second gravity separation step as it is used as a material, does not utilize the heavy gravity side of ash that has been sorted by the second gravity separation step as materials, or the heavy gravity The incineration ash particle sorting method according to claim 1, wherein the incineration ash on the side is subjected to a melting treatment or a firing treatment .

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