JP5761544B1 - Method and apparatus for desalinating chlorine-containing ash - Google Patents

Abstract

A desalination treatment method and a desalination treatment apparatus capable of achieving a high desalting effect and capable of recovering washing ash suitable for a cement raw material or a fired aggregate raw material. An initial washing step in which washing water is added to chlorine-containing ash to form an initial slurry, and chlorine is leached into water, and a polymer flocculant is added to the initial slurry to precipitate and separate agglomerated flocs to obtain an initial concentrated slurry. An initial concentration step to be formed, a classification step in which the initial concentrated slurry is hydrated and then separated into a fine slurry and a coarse slurry using a wet cyclone, and a polymer flocculant is added to the fine slurry to further fine agglomerate A fine-grain concentration step in which flocs are settled to form a fine-grained concentrated slurry; a step in which the fine-grained concentrated slurry is dehydrated and washed to collect fine-grained washed ash; A method for desalinating chlorine-containing ash and an apparatus for desalinating, characterized by comprising a step of collecting washing ash. [Selection] Figure 1

Description

  The present invention relates to a method for desalinating chlorine-containing ash, and in particular, incineration ash (main ash, fly ash, burning husk, dust) discharged from an incinerator for municipal waste and industrial waste, and incineration from a landfill site. The present invention relates to a technology for efficiently desalting incineration ash having a high chlorine concentration such as ash or chlorine bypass dust generated from a cement factory with a small amount of washing water. The desalination treatment technique of the present invention can desalinate so that incinerated ash having a high chlorine concentration can be used as a cement raw material. In the present invention, the chlorine-containing ash is incinerated ash (main ash, fly ash, burning husk, dust) discharged from municipal incineration facilities and industrial waste incineration facilities, excavated incineration ash from landfill sites, and from cement factories. It means any one kind of chlorine bypass dust generated or a mixture thereof.

  Conventionally, incineration ash generated by intermediate treatment of municipal waste and industrial waste is landfilled or landfilled after melting and volume reduction. However, expansion of existing landfill sites and construction of new landfill sites are difficult due to social factors such as environmental regulations and lack of agreement with neighboring residents. Cement is mainly composed of oxides such as calcium, silicon, aluminum and iron, and waste containing these can be used as a cement raw material. Various wastes such as blast furnace slag and coal ash are actively used as raw materials for cement. Incinerated ash generated during the intermediate treatment of municipal waste and industrial waste is also being used as a raw material for cement.

  However, incineration ash such as municipal waste and industrial waste contains high concentrations of chlorine, so the cement produced when used as a cement raw material also contains a large amount of chlorine. When a large amount of chlorine is contained in the cement, the reinforcing bars are easily corroded, so that the durability of the reinforced concrete is lowered. The JIS standard (JIS R 5210) stipulates that the chlorine content in ordinary Portland cement is 350 ppm or less. On the other hand, incineration ash contains about 1 to 25 wt% of chlorine. When trying to use a high concentration of chlorine such as incinerated ash as a raw material for cement, only a very small amount can be used. The same problem arises when digging ash generated in reclamation works at landfill sites and chlorine bypass dust generated from cement factories are used as cement raw materials.

  Therefore, a wet desalting method using water leaching is known as a method for desalting wastes having a high chlorine concentration such as incinerated ash. When the chlorine-containing ash is washed with water, soluble components such as chlorine are dissolved in water, so that the chlorine concentration of the washed ash decreases. By sufficiently reducing the chlorine concentration of the washing ash, it can be used in large quantities as a cement raw material. Chlorine-containing ash can also be used as a raw material for calcined aggregate by the same wet desalting treatment. Moreover, the same wet desalting process can be used as a pretreatment when the chlorine-containing ash is melt-processed.

  However, when desalting high-chlorine ash slurry by one-step washing process and collecting the liquid and washing ash by solid-liquid separation, the desalination rate of the washing ash is low, or the variation in the chlorine concentration of the washing ash is large. Often not suitable for cement materials. In addition, the chlorine concentration in the washing wastewater is several g / L, often 10 g / L or more, so it is easy to cause metal corrosion of the equipment. Also, it contains high concentrations of metal ions such as calcium, so scales can be generated in piping and equipment. In addition, there is a problem that the load on the apparatus is large, such as the filter cloth used for solid-liquid separation being easily blocked.

In order to avoid such problems, the following methods are known as methods for treating chlorine-containing waste.
(Ii) A method of mixing and stirring incinerated ash and water, grinding and slurrying, classifying into coarse and fine particles with a water tank, and adding an acid to the fine-grained slurry for desalting (Patent Document 1) .
(B) A method in which incinerated ash is classified into coarse and fine particles using a sieve or wet cyclone, then the coarse particles are washed with water, and the fine particles are washed with water and chemically or physically washed for desalting. (Patent Document 2).
(C) Repeated mixing and dehydration of incineration ash and water to wash the incineration ash, performing centrifugation between the primary and secondary washings, and dehydrating until the moisture content of the solid wet ash is 60 wt% or less Then, a method of separating and desalting the washing water having a high chlorine concentration (Patent Document 3).

Japanese Patent No. 5561326 Japanese Patent No. 4937004 Japanese Patent No. 3818924

  In the desalting methods of Patent Document 1 and Patent Document 2, the incineration ash is roughly washed with water and then primary washed by stirring and mixing, etc., and classified into fine slurry and coarse slurry by a wet cyclone or water tank, Secondary cleaning is performed by chemical cleaning such as cleaning or acid addition. However, in these methods, the chlorine concentration in each slurry liquid remains the same as the liquidity at the time of primary cleaning even after classification, and the chlorine concentration in the liquid remains as high as several g / L to 10 g / L. Therefore, even if water and chemicals are added and secondary cleaning is performed, leaching of chlorine is suppressed, sufficient desalting cannot be performed, and the amount of water and chemicals for promoting desalting increases.

  In addition, in the method of Patent Document 1, elutriation is used for wet classification of fine grains and coarse grains. However, elutriation uses differences in particle diameter and sedimentation speed, so that ash particles are flocked. If a flocculated aggregate is formed, classification different from the original particle size distribution of the ash particles is performed, and there is a problem that classification efficiency is lowered. Furthermore, although the method of Patent Document 2 shows an example in which a wet cyclone is used as a means for classification and desalting and washing, since the residence time inside the cyclone is a very short time of several seconds, the leaching of chlorine into water Is insufficient. In addition, the classification efficiency of the wet cyclone is reduced unless the ash and water are sufficiently mixed and slurried.

  In the desalting method of Patent Document 3, centrifugal separation is performed between the primary washing and the secondary washing, and dehydration is performed until the water content of the wet ash in the solid content is 60 wt% or less to separate the washing water having a high chlorine concentration. However, since the wet ash having a water content of 60 wt% or less is in the form of a hard-pressed cake, it is necessary to pulverize it finely in order to resuspend and demineralize it. If the crushing is insufficient, the desalting efficiency after the secondary washing will decrease. Furthermore, although a strong stirring device using an impeller is used to resuspend wet ash having a water content of 60 wt% or less, running costs increase due to wear of the impeller and the like.

  The desalinization treatment method of the present invention overcomes the problems in the conventional method described above, and a slurry obtained by adding water to chlorine-containing ash is stirred for a predetermined time to perform desalting washing, and the slurry is polymer flocculant. Is added to separate the aggregated flocs by sedimentation and form a concentrated slurry, and then, the combined slurry is separated into a coarse slurry and a fine slurry, and then combined with a classification step for separating the concentrated slurry. Provided are a desalting method and a desalting apparatus that can achieve a desalting effect and can recover washing ash suitable for a cement raw material.

According to the present invention, a desalting treatment method having the following configuration is provided as a means for solving the above problems.
[1] An initial washing process in which washing water is added to chlorine-containing ash to form an initial slurry, and chlorine is leached into water, and a polymer flocculant is added to the initial slurry to precipitate and separate the aggregated floc to form an initial concentrated slurry. An initial concentration step of transferring chlorine of the chlorine-containing ash to the primary supernatant, a classification step of adding the initial concentrated slurry to water and then separating it into a fine slurry and a coarse slurry using a wet cyclone, and and a fine concentration step of shifting the said sub grains chlorine on the secondary supernatant water to form a fine particle concentrate slurry by adding a polymer flocculant to the settling of the fine flocs in the grain slurry, the Draining and desalting the primary supernatant water of the initial concentration step and the secondary supernatant water of the fine particle concentration step, and dewatering and washing the fine particle concentrated slurry to recover the desalted fine particle washed ash; the above Desalting method chlorine-containing ash and having a step of recovering the coarse cleaning ash desalted dehydrated washed particle slurry.
[2] Add washing water to the chlorine-containing ash to make an initial slurry with a solid content concentration of 30 to 300 g / L, add a polymer flocculant to the initial slurry and concentrate the solid content concentration to more than twice that of the initial slurry. The initial concentration slurry is separated into primary supernatant water, and 40 to 90% of the chlorine content contained in the chlorine-containing ash is transferred to the primary supernatant water and removed out of the system. Ash desalting method.
[3] Washing water is added to the initial concentrated slurry to form a diluted slurry having a solid content concentration of 10 to 150 g / L, and the diluted slurry is introduced into a wet cyclone to obtain coarse particles having a 50% particle size of 30 μm to 1000 μm. The chlorine-containing ash desalting method according to the above [1] or [2], wherein the coarse slurry is classified into a coarse slurry containing and a fine slurry containing fine particles having a 50% particle diameter of less than 30 μm .
[4] Add a polymer flocculant to the fine-grain slurry to precipitate and separate fine-grain ash, and concentrate the fine-grained slurry to a concentration of solids more than twice that of the fine-grain slurry, and secondary supernatant water. The above-mentioned [1] to [3] are separated and transferred to the secondary supernatant to transfer 5 to 60% of the amount of chlorine contained in the chlorine-containing ash and remove it outside the system, and recover the fine-grained concentrated slurry. A method for desalinating chlorine-containing ash according to any one of the above.
[5] The recovered fine-grained concentrated slurry is dewatered and washed, and the fine-grained washed ash in which the amount of chlorine contained in the chlorine-containing ash at the start of treatment is reduced to 1/2 to 1/60 is collected. The method for desalinating chlorine-containing ash according to any one of [4] above.
[6] The [1] to [1] to recover the coarse-grained ash in which the coarse-grain slurry is washed and solid-liquid separated to reduce the amount of chlorine contained in the chlorine-containing ash at the start of the treatment to 1/2 to 1/100 The method for desalinating chlorine-containing ash according to any one of [4] above.
[7] The method for desalinating chlorine-containing ash according to any one of [1] to [6], wherein the step of introducing the diluted slurry into a wet cyclone and classifying the slurry into a fine slurry and a coarse slurry is performed a plurality of times. .
[8] The diluted slurry is introduced into a wet cyclone and classified into a primary fine slurry and a primary coarse slurry, and washing water is added to the primary coarse slurry to obtain a secondary diluted slurry having a solid content concentration of 10 to 150 g / L. The secondary diluted slurry is again introduced into the wet cyclone and classified into a secondary fine slurry and a secondary coarse slurry, and the secondary fine slurry and the primary fine slurry are mixed to obtain a total fine slurry. The method for desalinating chlorine-containing ash as described in [7] above, wherein a polymer flocculant is added to the total fine particle slurry to precipitate the fine particles to obtain a fine particle concentrated slurry.
[9] The method for desalinating chlorine-containing ash according to any one of [1] to [8] above, wherein the coarse washed ash and the fine washed ash are collected and used as a cement raw material.
[10] Main ash and fly ash generated from the intermediate treatment of municipal waste, burning husks and dust generated from the intermediate treatment of industrial waste, excavated ash generated from reclamation work at landfill sites, or chlorine bypass generated from cement factories The method for desalinating chlorine-containing ash according to any one of [1] to [9] above, wherein the dust is treated.

Moreover, according to this invention, the desalination processing apparatus which has the following structures is provided.
[11] Means for adding washing water to chlorine-containing ash to form an initial slurry, leaching chlorine into water, means for stirring the initial slurry, means for adding a polymer flocculant to the initial slurry, and separating and separating the aggregated floc Forming an initial concentrated slurry , transferring chlorine from the chlorine-containing ash to the primary supernatant water, separating the supernatant from the supernatant water, removing the supernatant water from the system, and adding washing water to the initial concentrated slurry. Means for forming a diluted slurry, a wet cyclone for classifying the diluted slurry into a fine slurry and a coarse slurry, and adding a polymer flocculant to the fine slurry to precipitate and separate the fine particles to form a fine concentrated slurry . means for separating the upper supernatant water by migrating said sub grains chlorine above supernatant water, means for recovering fine cleaning ash desalted dehydrated washed said sub grain concentrated slurry, the coarse particle slurry was dehydrated washed with Desalination apparatus chlorine-containing ash, characterized in that it comprises means for recovering desalted coarse cleaning ashes.

[Specific description]
The desalination treatment method of the present invention includes an initial washing step of adding washing water to chlorine-containing ash to form an initial slurry and leaching chlorine into water, and adding a polymer flocculant to the initial slurry to remove ash particles in the slurry. An initial concentration step in which an initial concentrated slurry is formed by settling and separating as an aggregate floc, a classification step in which the initial concentrated slurry is separated into a fine slurry and a coarse slurry by a wet cyclone, and a polymer flocculant in the fine slurry The fine-grained aggregated flocs are settled and separated to form a fine-grained concentrated slurry, the fine-grained concentrated slurry is dehydrated and washed to recover the fine-grained washed ash, and the coarse-grained slurry is A method for desalinating chlorine-containing ash, comprising a step of dewatering and washing to collect coarse-grained washed ash.
1 to 4 show process diagrams of the desalting method of the present invention.

[Initial cleaning process]
In the desalination treatment method of the present invention, as the first step, washing water is added to the chlorine-containing ash, guided to a mixing tank, stirred for a predetermined time, and leached into water as an initial slurry (initial washing step). The amount of washing water is preferably an amount of water that transfers 40 to 90% of the amount of chlorine contained in the chlorine-containing ash to the supernatant water in the subsequent sedimentation separation. Specifically, for example, a slurry with a solid content concentration of 30 to 300 g / L is used. Is preferred. In order to obtain this solid content concentration, it is generally preferable to add 2 to 20 times as much washing water as the chlorine-containing ash weight at the start of the treatment. If the water content of the slurry is less than this, it will be insufficient to dissolve chlorine contained in the chlorine-containing ash in water. If the amount of water in the slurry is greater than this, the amount of supernatant water in the sedimentation tank increases, and the burden of wastewater treatment becomes excessive. For the initial cleaning, a square or cylindrical complete mixing tank with a stirrer used in a general chemical apparatus, or a rotating drum type mixing tank can be used. The complete mixing tank may be one tank, or a plurality of tanks may be arranged in series or in parallel. In the rotating drum type mixing tank, the slurry may be stirred as it is, or a ball-shaped or rod-shaped grinding medium may be added. When foreign substances having different properties from those of ash having a particle diameter of 5 to 20 mm or more are mixed in the chlorine-containing ash, it may be removed in advance by screening or magnetic separation.

[Initial concentration step]
A polymer flocculant is added to the initial slurry, and the ash particles in the slurry are settled and separated as agglomerated flocs to form an initial concentrated slurry (initial concentration step). For example, the initial slurry to which the polymer flocculant is added is guided to a sedimentation separation tank to separate and separate the ash particles, thereby forming an initial concentrated slurry. It is preferable that the slurry has a solid content concentration concentrated to at least twice that of the initial slurry. For example, when the initial slurry has a solid content of 60 g / L, it is preferably concentrated to about 300 g / L, and when the initial slurry has a solid content of 30 g / L, it is preferably concentrated to 250 g / L or more. Normally, the concentration of the solid content of the slurry to 400 g / L or more requires a long sedimentation time, and blockage in the pipe is likely to occur. Therefore, in actual operation, the upper limit of the solid content concentration is 400 g / L. It is preferable to carry out the concentration to a degree.

  By concentrating the slurry, the chlorine contained in the concentrated ash is easily leached into the washing water. By concentrating the solid content concentration of the slurry to more than twice that of the initial slurry, approximately 40 to 90% of the amount of chlorine contained in the chlorine-containing ash can be transferred to the primary supernatant and discharged out of the system. . In the sedimentation separation tank, it is separated into the initial concentrated slurry at the bottom of the tank and the primary supernatant water above it, and since the primary supernatant water is leached in large quantities of chlorine and calcium, the primary supernatant is removed from the system, The initial concentrated slurry is extracted from the sedimentation tank.

[Classification process]
Washing water is added to the initial concentrated slurry extracted from the settling tank to form a diluted slurry. The solid content concentration of the diluted slurry is preferably 10 to 150 g / L. In order to achieve this solid content concentration, it is generally preferable to add 0.5 to 40 times the amount of the washing water to the initial concentrated slurry. If the amount of water in the diluted slurry is less than this, the viscosity of the slurry increases, so that the flow state becomes poor and classification of coarse particles and fine particles becomes difficult. On the other hand, if the amount of water in the diluted slurry is larger than this, the burden of sedimentation separation in the subsequent fine-grain concentration step becomes excessive.

  The diluted slurry is introduced into a wet cyclone and classified into a coarse slurry and a fine slurry. The ash particles in the diluted slurry form a floc in which a large number of particles are aggregated in a higher order due to the crosslinking action of the polymer flocculant. For this reason, when performing normal elutriation or sieving, classification according to the particle size of the aggregated flocs is performed, resulting in a classification result different from the original particle size distribution of the ash particles. On the other hand, the wet cyclone has an effect of breaking the cross-linking bond by the polymer flocculant due to the shear stress due to the centrifugal force and dispersing it in the primary particles, so that a classification result corresponding to the particle size distribution of the ash particles is easily obtained.

The classification is preferably performed into a coarse slurry containing coarse particles having a 50% particle size of 30 μm or more and 1000 μm or less and a fine slurry containing fine particles having a 50% particle size of less than 30 μm . Here, the 50% diameter particle is a particle diameter indicating 50% in the distribution curve of the cumulative weight ratio of the volume particle size distribution of the particles. In general, the chlorine concentration of fine ash is higher than that of coarse ash because chlorine tends to be concentrated in fine particles. By classifying the diluted slurry into a fine slurry and a coarse slurry, a large amount of chlorine can be transferred to the fine slurry, and the chlorine concentration of the coarse slurry can be reduced. The standard particle diameter (referred to as a classified diameter) for classification into coarse and fine particles is preferably 30 μm to 100 μm, more preferably 30 μm to 80 μm. If the classification diameter is smaller than this range, precise classification must be performed, so that the treatment flow rate of the wet cyclone must be reduced and the multistage treatment of the wet cyclone must be performed, which increases the treatment cost per ash weight. . On the other hand, if the particle diameter based on classification is larger than this range, the distribution ratio of the particles transferred to the fine slurry becomes too high, and the load on the solid-liquid separation facility for the fine slurry in the subsequent stage becomes large. In particular, the optimum particle size for classification may be determined in consideration of the particle size distribution of the chlorine-containing ash and the weight distribution ratio of the fine-grained washing ash and the solid washing ash. The classification diameter is preferably such that the weight distribution ratio of the fine-grain washing ash and the solid washing ash is about 1: 1 to about 1: 3, and more preferably the classification diameter is about 1: 1. The classification diameter can be adjusted by increasing or decreasing the factor that affects the centrifugal force of the particles, for example, the cyclone inner diameter or the slurry flow rate to the cyclone.

[Fine grain concentration process]
A fine-grain slurry is extracted and a polymer flocculant is added, and fine-grained ash is settled and separated into a fine-grain concentrated slurry (fine-grain concentration step). For example, a fine particle slurry to which a polymer flocculant is added is guided to a settling tank, and fine ash is precipitated and separated as agglomerated flocs to form a fine particle concentrated slurry. It is preferable to use a slurry in which the solid concentration is more than twice that of the fine slurry.

  By concentrating the slurry, chlorine contained in the fine ash can be discharged out of the system as a supernatant. By concentrating the solid content concentration of the slurry to more than twice that of the fine slurry, approximately 5 to 60% of the chlorine content in the incinerated ash can be transferred to the secondary supernatant and discharged out of the system. it can. In the sedimentation separation tank, it is separated into a fine-grained concentrated slurry at the bottom of the tank and the secondary supernatant water on the upper side, and since a relatively large amount of chlorine is dissolved in the secondary supernatant water, the secondary supernatant water is removed, The fine concentrated slurry is extracted from the sedimentation tank. Note that desalting at the time of concentration may be promoted by adding a polymer flocculant after adding a desalting aid to the fine-grain slurry. Further, a sedimentation aid may be added to the fine particle slurry together with the polymer flocculant to accelerate the sedimentation rate.

  The desalting effect can be enhanced by introducing the diluted slurry into a wet cyclone and classifying the slurry into a fine slurry and a coarse slurry a plurality of times. An example in which classification is performed in two stages is shown in FIG.

  As shown in FIG. 2, the diluted slurry is introduced into a wet cyclone and classified into a primary fine grain slurry and a primary coarse grain slurry. Further, wash water is added to the primary coarse slurry to form a secondary diluted slurry. It is preferable to dilute to a solid content concentration of 10 to 150 g / L. In order to obtain this solid content concentration, it is generally preferable to add 0.5 to 60 times as much washing water as the ash weight at the start of the treatment to the primary fine particle slurry.

  The secondary diluted slurry is again introduced into the wet cyclone and classified into a secondary fine slurry and a secondary coarse slurry. Further, the secondary fine slurry and the primary fine slurry are mixed to make a total fine slurry. A polymer flocculant is added to the total fine-grain slurry, and the fine-grained ash is agglomerated flocs to settle and separate into a fine-grain concentrated slurry.

[Recovery process of fine-grained washed ash]
The fine-grained concentrated slurry is extracted from the sedimentation tank, dehydrated and washed. For example, the fine slurry is dehydrated with a filter press, the dehydrated cake is washed, the pore water in the cake is replaced with washing water, and desalted to recover fine solid content (fine washed ash). According to the desalting method of the present invention, for example, fine-grained washed ash in which the amount of chlorine contained in the ash at the start of treatment is reduced to 1/2 to 1/60 can be recovered.

[Coarse-grain washing ash recovery process]
The coarse slurry or the secondary coarse slurry is extracted from the wet cyclone and separated into solid and liquid to collect coarse solids (coarse washed ash). Since filter presses are expensive and have a low throughput per unit time, solid-liquid separation of coarse diluted slurry may be performed using a continuous processing device such as a centrifugal separator to reduce the load on the filter press. According to the desalting treatment method of the present invention, for example, it is possible to collect coarse-grain washed ash in which the amount of chlorine contained in the ash at the start of treatment is reduced to 1/2 to 1/100. When the particle concentration of the coarse particle slurry or the secondary coarse particle slurry is too high to be fluidized, it is preferable to add water so that the solid content concentration becomes 100 to 400 g / L.

  Further, when the chlorine concentration of the coarse slurry or the secondary coarse slurry is high, it is preferable to add water before solid-liquid separation to leach chlorine into the water and discharge the chlorine together with the waste water. In the case of ash with a very low content of coarse particles, or when the total amount of ash to be treated is very small, the efficiency may be reduced if the coarse particles and fine particles are treated separately. In such a case, the coarse slurry may be mixed with the fine slurry and processed with a filter press.

  In the above processing method of the present invention, secondary supernatant water extracted from the sedimentation separation tank or filtered water and washing water generated by solid-liquid separation may be reused by returning to the upper processing step for those having a low chlorine concentration. . For example, if the secondary supernatant water has a chlorine concentration of 5 g / L or less, it can be reused as washing water for the initial washing step of chlorine-containing ash or washing water for diluting the initial concentrated slurry. If it is filtered water or washing water in the solid-liquid separation process, the washing water in the initial washing process of chlorine-containing ash, the washing water in the initial concentrated slurry, or the washing water in the process of making the primary coarse slurry into a secondary dilution slurry Can be reused.

  In the treatment method, a commercially available anionic polymer flocculant may be used as the polymer flocculant. As the polymer flocculant, a solution previously dissolved in a concentration of 0.01 to 0.1% may be used. Further, as the desalting aid, acids such as sulfuric acid, nitric acid, carbonic acid, acetic acid, or liquids or solid powders thereof such as sodium salt, potassium salt, calcium salt, magnesium salt, aluminum salt, iron salt can be used.

  As an apparatus for carrying out the above desalination treatment method of the present invention, means for adding washing water to chlorine-containing ash and leaching the chlorine component into water as an initial slurry, means for adding a polymer flocculant to the initial slurry, agglomeration A means for separating the flocs by sedimentation into an initial concentrated slurry and supernatant water, a means for removing the supernatant water out of the system, a means for adding washing water to the initial concentrated slurry to form a diluted slurry, A wet cyclone for classifying into a fine particle slurry and a coarse particle slurry, means for adding a polymer flocculant to the fine particle slurry to precipitate and separate fine ash and separating it into a fine particle concentrated slurry and supernatant water, and the fine particle concentrated slurry A desalinization treatment apparatus provided with means for recovering fine-grained washed ash by dehydration and washing, and means for collecting the coarse-grained slurry by dehydrating and washing the coarse-grain slurry can be used.

  The desalination treatment method of the present invention performs an initial washing step in which chlorine-containing ash is made into a slurry and a chlorine component is leached into water, and a polymer flocculant is added to the slurry to precipitate and separate the aggregated floc to form a concentrated slurry. This is a processing method that combines a classification step of separating the concentrated slurry thus formed into a coarse slurry and a fine slurry, and the chlorine concentration at an early stage by concentrating the slurry first. Since the high supernatant water is removed from the system, the subsequent desalting and washing becomes easy, and the chlorine concentration of the washing ash can be greatly reduced. Further, since the chlorine concentration is gradually reduced, the chlorine concentration can be surely lowered, and the chlorine concentration of the cleaning ash is also stabilized. Furthermore, corrosion and scale generation of the apparatus can be reduced, and the amount of water used can be reduced.

  In the desalting method of the present invention, after the initial concentration step, classification is performed using a wet cyclone, so that the aggregation floc is broken and classification corresponding to the particle size distribution of the original ash particles is performed. Since optimum desalting washing and solid-liquid separation are performed, a high desalting effect can be obtained. The agglomeration treatment prior to classification is not carried out by the conventional treatment method because it is likely to be mistaken so as to reduce the classification effect, but the treatment method of the present invention utilizes the shear stress of the wet cyclone. Since classification can be performed while destroying the aggregated floc, the classification effect can be greatly enhanced.

  According to the desalination treatment method of the present invention, for example, 96% or more of coarse washing ash is removed from high-chlorine incinerated ash having a chlorine concentration of 14 wt% to 15 wt%, and the chlorine of fine washing ash is removed. 94% or more can be removed, and the coarse and fine ash can be used as a raw material for cement. The washed ash that has been desalted in the same manner can also be used as a raw material for the calcined aggregate. Moreover, the said desalting process method can be applied as a pre-processing at the time of melt-processing a chlorine containing ash.

  If the fine-grained washed ash has a high chlorine concentration and is difficult to reuse, only the coarse-grained washed ash can be reused. In this case, the fine ash is disposed of in landfill, but the weight of soluble components and coarse ash is reduced compared with the ash before desalting and washing, so the weight of ash to be disposed of is about 3/10 or less. There is a large volume reduction effect.

  The desalination treatment method of the present invention is not limited to incineration ash (main ash, fly ash, burning husk, dust) of municipal waste and industrial waste, but is generated from excavated ash generated in the reclamation work at the final disposal site, or from a cement factory Incineration ash having a high chlorine concentration such as chlorine bypass dust can be treated alone or in combination. The desalting method of the invention includes an embodiment for treating these chlorine-containing ashes.

Process drawing which shows the example of the desalinating method (Example 1, 5, 7, 9) of this invention. Process drawing which shows the example of the desalinating method (Example 2, 6, 8, 10) of this invention. Process drawing which shows the example of the desalination processing method (Example 4, 12) of this invention. Process drawing which shows the example of the desalinating process method (Example 3, 11) of this invention.

  Examples of the present invention are shown below together with comparative examples. The chlorine concentration of the chlorine-containing ash was evaluated by filtering the residue after dissolving 10% nitric acid and measuring the chlorine concentration in the filtrate by a coulometric titration method. The coulometric titration apparatus used was SALMAT-100 manufactured by Chuken Consulting. The wet cyclone used was Hitachi Zosen's Cyclone MD-3. As the wet sieve, a standard sieve having a mesh size of 32 micrometers manufactured by Tokyo Screen was used.

[Example 1]
10kg of dust (chlorine concentration 13wt%) generated when industrial waste is incinerated is put into a mixing and stirring tank, 10 times the amount of dust is added to washing water, and an initial slurry with a solid content of 95g / L And mixed and stirred for 10 minutes. The solid content concentration after 10 minutes of mixing and stirring was reduced to 60 g / L due to the dissolution of soluble components in water. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the slurry so that the concentration in the stirring tank would be 1 ppm, mixed, and then introduced into the settling tank, where the solid content concentration was 4.3. The mixture was allowed to stand until it was concentrated twice, so that the solid content was settled, and 80.4 L of the upper primary supernatant water was extracted and removed to obtain an initial concentrated slurry. The chlorine concentration of the primary supernatant water was 13.4 g / L.
24.6 L of the initial concentrated slurry was extracted from the sedimentation tank. The solid content concentration was 256 g / L. Washing water of 5 times the initial dust weight was added to form a diluted slurry having a solid content concentration of 84 g / L, and mixed and stirred for 10 minutes. The diluted slurry was introduced into a wet cyclone, and 17.4 L of coarse slurry was classified on the underflow side, and 57.2 L of fine slurry was classified on the overflow side. At this time, the 50% particle size of the coarse slurry was 75 μm, and the 50% particle size of the fine slurry was 15 μm.
Washing water of 4 times the initial dust weight was added to the coarse slurry and mixed and stirred for 10 minutes to obtain a coarse diluted slurry with a solid content concentration of 71 g / L. After the coarse-grain diluted slurry is put into a centrifuge and dehydrated, the dehydrated cake is washed with washing water having an amount equivalent to the initial dust weight to remove adhering water on the surface, and the coarse-grain washed ash 4 Obtained 1 kg. Water was drained as a coarse filtrate.
On the other hand, the fine slurry is extracted from the wet cyclone and introduced into the mixing and stirring layer, and an anionic polymer flocculant (trade name: Diafloc AP-825B) is added to the stirring tank so that the concentration in the stirring tank is 0.5 ppm. After mixing, the mixture was introduced into a sedimentation separation tank and allowed to stand until the solid concentration was 4.3 times that of the fine particle slurry, so that the solid content was settled to obtain a fine particle concentrated slurry having a solid content concentration of 165 g / L. The secondary supernatant water on the upper side of the fine-grained concentrated slurry was extracted. The chlorine concentration of the secondary supernatant water was 3.7 g / L. The fine-grained concentrated slurry was dehydrated with a filter press, and the dehydrated cake was washed with washing water twice as much as the initial dust weight, and the surface adhering water was removed to obtain 2.2 kg of fine-grain washed ash. The water was drained as a fine filtrate.
The recovered coarse ash and fine ash have a chlorine concentration of 0.40 wt% and 0.44 wt%, respectively, which can be used as cement raw materials.

[Example 2]
10kg of dust (chlorine concentration 13wt%) generated when industrial waste is incinerated is put into a mixing and stirring tank, 10 times the amount of dust is added to washing water, and an initial slurry with a solid content of 95g / L And mixed and stirred for 10 minutes. The solid content concentration after 10 minutes of mixing and stirring was reduced to 60 g / L due to the dissolution of soluble components in water. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the slurry so that the concentration in the stirring tank would be 1 ppm, mixed, and then introduced into the settling tank, where the solid content concentration was 4.3. The mixture was allowed to stand until it was concentrated twice, so that the solid content was settled, and 80.4 L of the upper primary supernatant water was extracted and removed to obtain an initial concentrated slurry. The chlorine concentration of the primary supernatant water was 13.4 g / L.
24.6 L of the initial concentrated slurry was extracted from the sedimentation tank. The solid content concentration was 256 g / L. Washing water of 5 times the initial dust weight was added to make a primary dilution slurry with a solid concentration of 84 g / L, and the mixture was stirred for 10 minutes. The primary diluted slurry was introduced into a wet cyclone, and 17.4 L of primary coarse slurry was classified on the underflow side, and 57.2 L of primary fine slurry was classified on the overflow side. At this time, the 50% particle size of the primary coarse slurry was 75 μm, and the 50% particle size of the primary fine slurry was 15 μm.
The primary coarse slurry was extracted from the wet cyclone, and washed water of 4 times the initial dust weight was added to make a secondary diluted slurry with a solid concentration of 71 g / L, and mixed and stirred for 10 minutes. The secondary diluted slurry was introduced into a wet cyclone and classified into a secondary coarse slurry 14.3L and a secondary fine slurry 43.1L. At this time, the 50% particle size of the secondary coarse particle slurry was 71 μm, and the 50% particle size of the secondary fine particle slurry was 18 μm. After the secondary coarse slurry is put into a centrifuge and dehydrated, the dehydrated cake is washed with washing water having an amount equivalent to the initial dust weight to remove adhering water on the surface, and the coarse washed ash 3.1 kg was obtained. Water was drained as a coarse filtrate.
On the other hand, the primary fine particle slurry and the secondary fine particle slurry were extracted from each wet cyclone and mixed to obtain a total fine particle slurry. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the total fine particle slurry so that the concentration in the stirring tank was 0.5 ppm, and the mixture was stirred and mixed. The solid content was allowed to settle until it was concentrated to 4.1 times the total fine-grain slurry, to obtain a fine-grain concentrated slurry having a solid content concentration of 131 g / L. The secondary supernatant water on the upper side of the fine-grained concentrated slurry was extracted. The chlorine concentration of the secondary supernatant water was 2.6 g / L. The fine-grained concentrated slurry was dehydrated with a filter press, and the dehydrated cake was washed with washing water twice the initial dust weight to remove the adhering water on the surface to obtain 3.2 kg of fine-grain washed ash. The water was drained as a fine filtrate.
The recovered coarse-grained ash and fine-grained ash had a chlorine concentration of 0.30 wt% and 0.44 wt%, respectively, both of which could be used as cement raw materials.

Example 3
The same test as in Example 1 was performed, and 43.9 L of secondary supernatant water having a chlorine concentration of 3.7 g / L,
90.8 L of dehydrated washing water having a chlorine concentration of 0.38 g / L was obtained by mixing the whole amount of the coarse filtrate and the fine filtrate. Implementation was performed except that 43.9 L of the secondary supernatant water and 56.1 L of the dehydrated washing water were used as 100 L of the initial slurry washing water, and 34.7 L of the dehydrated washing water was reused as part of the 50 L diluted washing water. In the same manner as in Example 1, 10 kg of soot dust (chlorine concentration: 13 wt%) was treated to obtain 4.1 kg of coarse grain washed ash and 2.2 kg of fine grain washed ash. The recovered coarse ash and fine ash have a chlorine concentration of 0.41 wt% and 0.46 wt%, respectively, and both can be used as cement raw materials.

Example 4
The same test as in Example 2 was performed, and 75.8 L of secondary supernatant water having a chlorine concentration of 2.6 g / L,
58.5 L of dehydrated washing water having a chlorine concentration of 0.10 g / L was obtained by mixing all of the coarse and fine filtrates. Implementation was performed except that 75.8 L of the secondary supernatant water and 24.2 L of the dehydrated washing water were used as 100 L of the initial slurry washing water, and 34.3 L of the dehydrated washing water was reused as a part of 50 L of the diluted slurry washing water. In the same manner as in Example 2, 10 kg of dust (chlorine concentration: 13 wt%) was treated to obtain 3.1 kg of coarse-grained washed ash and 3.2 kg of fine-grained washed ash. The recovered coarse ash and fine ash have a chlorine concentration of 0.31 wt% and 0.47 wt%, respectively, which can be used as cement raw materials.

Example 5
Put 10kg of husks (chlorine concentration 1.6wt%) generated when incinerating industrial waste into a mixing and stirring tank, and add 10 times the weight of the husk weight of washing water to a solid content concentration of 95g / L. The slurry was prepared as an initial slurry and mixed and stirred for 10 minutes. The solid concentration after mixing and stirring for 10 minutes was reduced to 90 g / L due to the dissolution of soluble components in water. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the slurry so that the concentration in the stirring tank would be 1 ppm, mixed, and then introduced into the settling tank, where the solid content concentration was 3.4. The solid content was settled by allowing to stand until it was concentrated twice, and 74.3 L of the upper primary supernatant was extracted and removed to obtain an initial concentrated slurry. The chlorine concentration of the primary supernatant water was 1.6 g / L.
30.7 L of the initial concentrated slurry was extracted from the sedimentation tank. The solid content concentration was 309 g / L. Washing water in an amount 5 times the weight of the initial husk was added to form a diluted slurry having a solid content of 118 g / L, and mixed and stirred for 10 minutes. The diluted slurry was introduced into a wet cyclone, and 18.8 L of coarse slurry was classified on the underflow side, and 61.9 L of fine slurry was classified on the overflow side. At this time, the 50% particle diameter of the coarse slurry was 435 μm, and the 50% particle diameter of the fine slurry was 10 μm.
Washing water having an amount of 4 times the initial burning husk weight was added to the coarse slurry and mixed and stirred for 10 minutes to obtain a coarse diluted slurry having a solid content concentration of 112 g / L. The coarse diluted slurry is put into a centrifuge and dehydrated, and then the dehydrated cake is washed with washing water having an amount equal to the initial burning husk weight to remove adhering water on the surface, and the coarse washed ash 6 0.6 kg was obtained. Water was drained as a coarse filtrate.
On the other hand, the fine slurry is extracted from the wet cyclone and introduced into the mixing and stirring layer, and an anionic polymer flocculant (trade name: Diafloc AP-825B) is added to the stirring tank so that the concentration in the stirring tank is 0.5 ppm. After mixing, the mixture was introduced into a sedimentation separation tank and allowed to stand until the solid content was concentrated to 3.9 times that of the fine particle slurry, so that the solid content was settled to obtain a fine particle concentrated slurry having a solid content concentration of 183 g / L. The secondary supernatant water on the upper side of the fine-grained concentrated slurry was extracted. The chlorine concentration of the secondary supernatant water was 0.44 g / L. The fine-grained concentrated slurry was dehydrated with a filter press, and the dehydrated cake was washed with washing water twice the initial burning husk weight to remove the adhering water on the surface to obtain 2.9 kg of fine-grain washed ash. The water was drained as a fine filtrate.
The recovered coarse ash and fine ash have a chlorine concentration of 0.13 wt% and 0.16 wt%, respectively, and both can be used as cement raw materials.

Example 6
Put 10kg of husks (chlorine concentration 1.6wt%) generated when incinerating industrial waste into a mixing and stirring tank, and add 10 times the weight of the husk weight of washing water to a solid content concentration of 95g / L. The slurry was prepared as an initial slurry and mixed and stirred for 10 minutes. The solid concentration after mixing and stirring for 10 minutes was reduced to 90 g / L due to the dissolution of soluble components in water. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the slurry so that the concentration in the stirring tank would be 1 ppm, mixed, and then introduced into the settling tank, where the solid content concentration was 3.4. The solid content was settled by allowing to stand until it was concentrated twice, and 74.3 L of the upper primary supernatant was extracted and removed to obtain an initial concentrated slurry. The chlorine concentration of the primary supernatant water was 1.6 g / L.
30.7 L of the initial concentrated slurry was extracted from the sedimentation tank. The solid content concentration was 309 g / L. Washing water in an amount 5 times the weight of the initial husk was added to obtain a primary diluted slurry having a solid content concentration of 118 g / L, and mixed and stirred for 10 minutes. The primary diluted slurry was introduced into a wet cyclone, and 18.8 L of primary coarse slurry was classified on the underflow side, and 61.9 L of primary fine slurry was classified on the overflow side. At this time, the 50% particle size of the primary coarse particle slurry was 435 μm, and the 50% particle size of the primary fine particle slurry was 10 μm.
The primary coarse slurry was extracted from the wet cyclone, and washed water having an amount of 4 times the initial burning husk weight was added to form a secondary diluted slurry having a solid concentration of 112 g / L, and mixed and stirred for 10 minutes. The secondary diluted slurry was introduced into a wet cyclone, secondary coarse slurry 14.7L was classified on the underflow side, and secondary fine slurry 44.1L was classified on the overflow side. At this time, the 50% particle size of the secondary coarse particle slurry was 445 μm, and the 50% particle size of the secondary fine particle slurry was 12 μm. After the secondary coarse slurry is put into a centrifuge and dehydrated, the dehydrated cake is washed with washing water having an amount equal to the initial burning husk weight to remove adhering water on the surface, and the coarse washed ash 4.9 kg was obtained. Water was drained as a coarse filtrate.
On the other hand, the primary fine particle slurry and the secondary fine particle slurry were extracted from each wet cyclone and mixed to obtain a total fine particle slurry. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the total fine particle slurry so that the concentration in the stirring tank was 0.5 ppm, and the mixture was stirred and mixed. The solid content was allowed to settle until it was concentrated to 4.0 times the total fine-particle slurry, to obtain a fine-grain concentrated slurry having a solid content concentration of 174 g / L. The secondary supernatant water on the upper side of the fine-grained concentrated slurry was extracted. The chlorine concentration of the secondary supernatant water was 0.28 g / L. The fine-grained concentrated slurry was dehydrated with a filter press, and the dehydrated cake was washed with washing water twice the initial burning husk weight to remove adhering water on the surface to obtain 4.6 kg of fine-grain washed ash. The water was drained as a fine filtrate.
The recovered coarse ash and fine ash have a chlorine concentration of 0.11 wt% and 0.16 wt%, respectively, which can be used as cement raw materials.

Example 7
Put 10kg of husks (chlorine concentration 1.6wt%) generated when incinerating industrial waste into a mixing and stirring tank, and add 10 times the weight of the husk weight of washing water to a solid content concentration of 95g / L. The slurry was prepared as an initial slurry and mixed and stirred for 10 minutes. The solid concentration after mixing and stirring for 10 minutes was reduced to 90 g / L due to the dissolution of soluble components in water. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the slurry so that the concentration in the stirring tank would be 1 ppm, mixed, and then introduced into the settling tank, where the solid content concentration was 3.4. The solid content was settled by allowing to stand until it was concentrated twice, and 74.3 L of the upper primary supernatant was extracted and removed to obtain an initial concentrated slurry. The chlorine concentration of the primary supernatant water was 1.6 g / L.
30.7 L of the initial concentrated slurry was extracted from the sedimentation tank. The solid content concentration was 309 g / L. Washing water in an amount 5 times the weight of the initial husk was added to form a diluted slurry having a solid content of 118 g / L, and mixed and stirred for 10 minutes. The diluted slurry was introduced into a wet cyclone, and 17.0 L of coarse slurry was classified on the underflow side, and 63.7 L of fine slurry was classified on the overflow side. At this time, the 50% particle size of the coarse slurry was 454 μm, and the 50% particle size of the fine slurry was 24 μm.
Washing water of 4 times the weight of the initial burning husk was added to the coarse slurry and mixed and stirred for 10 minutes to obtain a coarse diluted slurry having a solid content concentration of 105 g / L. The coarse diluted slurry is put into a centrifuge and dehydrated, and then the dehydrated cake is washed with washing water having an amount equal to the initial burning husk weight to remove adhering water on the surface, and the coarse washed ash 6 0.0kg was obtained. Water was drained as a coarse filtrate.
On the other hand, the fine slurry is extracted from the wet cyclone and introduced into the mixing and stirring layer, and an anionic polymer flocculant (trade name: Diafloc AP-825B) is added to the stirring tank so that the concentration in the stirring tank is 0.5 ppm. After mixing, the mixture was guided to a sedimentation separation tank and allowed to stand until the solid content was concentrated to 3.5 times that of the fine slurry, so that the solid content was settled to obtain a fine slurry with a solid content of 198 g / L. The secondary supernatant water on the upper side of the fine-grained concentrated slurry was extracted. The chlorine concentration of the secondary supernatant water was 0.39 g / L. The fine-grained concentrated slurry was dehydrated with a filter press, and the dehydrated cake was washed with washing water twice the initial burning husk weight to remove the surface adhering water to obtain 3.5 kg of fine-grain washed ash. The water was drained as a fine filtrate.
The recovered coarse ash and fine ash have a chlorine concentration of 0.12 wt% and 0.17 wt%, respectively, and both can be used as cement raw materials.

Example 8
Put 10kg of husks (chlorine concentration 1.6wt%) generated when incinerating industrial waste into a mixing and stirring tank, and add 10 times the weight of the husk weight of washing water to a solid content concentration of 95g / L. The slurry was prepared as an initial slurry and mixed and stirred for 10 minutes. The solid concentration after mixing and stirring for 10 minutes was reduced to 90 g / L due to the dissolution of soluble components in water. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the slurry so that the concentration in the stirring tank would be 1 ppm, mixed, and then introduced into the settling tank, where the solid content concentration was 3.4. The solid content was settled by allowing to stand until it was concentrated twice, and 74.3 L of the upper primary supernatant was extracted and removed to obtain an initial concentrated slurry. The chlorine concentration of the primary supernatant water was 1.6 g / L.
30.7 L of the initial concentrated slurry was extracted from the sedimentation tank. The solid content concentration was 309 g / L. Washing water in an amount 5 times the weight of the initial husk was added to obtain a primary diluted slurry having a solid content concentration of 118 g / L, and mixed and stirred for 10 minutes. The primary diluted slurry was introduced into a wet cyclone, and 17.0 L of the primary coarse slurry was classified on the underflow side, and 63.7 L of the primary fine slurry was classified on the overflow side. At this time, the 50% particle size of the primary coarse particle slurry was 454 μm, and the 50% particle size of the primary fine particle slurry was 24 μm.
The primary coarse slurry was extracted from the wet cyclone, and washed water having an amount 4 times the weight of the initial burning husk was added to obtain a secondary diluted slurry having a solid concentration of 105 g / L, and mixed and stirred for 10 minutes. The secondary dilution slurry was introduced into a wet cyclone and classified into a secondary coarse slurry 12.0 L and a secondary fine slurry 45.0 L. At this time, the 50% particle size of the secondary coarse particle slurry was 461 μm, and the 50% particle size of the secondary fine particle slurry was 26 μm. After the secondary coarse slurry is put into a centrifuge and dehydrated, the dehydrated cake is washed with washing water having an amount equal to the initial burning husk weight to remove adhering water on the surface, and the coarse washed ash 4.7 kg was obtained. Water was drained as a coarse filtrate.
On the other hand, the primary fine particle slurry and the secondary fine particle slurry were extracted from each wet cyclone and mixed to obtain a total fine particle slurry. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the total fine particle slurry so that the concentration in the stirring tank was 0.5 ppm, and the mixture was stirred and mixed. The solid content was allowed to settle until it was concentrated to 4.1 times the total fine-particle slurry, and a solid-concentrated slurry having a solid content concentration of 186 g / L was obtained. The secondary supernatant water on the upper side of the fine-grained concentrated slurry was extracted. The chlorine concentration of the secondary supernatant was 0.21 g / L. The fine-grained concentrated slurry was dehydrated with a filter press, and the dehydrated cake was washed with washing water twice as much as the initial burning husk weight to remove surface adhering water to obtain 4.8 kg of fine-grain washed ash. The water was drained as a fine filtrate.
The recovered coarse-grained ash and fine-grained ash had a chlorine concentration of 0.10 wt% and 0.18 wt%, respectively, both of which could be used as cement raw materials.

Example 9
Put 10kg of husks (chlorine concentration 1.6wt%) generated when incinerating industrial waste into a mixing and stirring tank, and put in washing water 5 times the weight of the husks. The solid content concentration is 181g / L. The slurry was prepared as an initial slurry and mixed and stirred for 10 minutes. The solid content concentration after 10 minutes of mixing and stirring was reduced to 173 g / L due to dissolution of soluble components in water. An anionic polymer flocculant (trade name Diaflock AP-825B) was added to and mixed with the slurry so that the concentration in the stirring tank was 1 ppm, and then introduced into the settling tank, so that the solid content concentration was 2.0. The solid content was allowed to settle until it was concentrated twice, and 27.5 L of the upper primary supernatant water was extracted and removed to obtain an initial concentrated slurry. The chlorine concentration of the primary supernatant water was 3.1 g / L.
27.5 L of the initial concentrated slurry was extracted from the sedimentation tank. The solid content concentration was 344 g / L. Washing water of 5 times the weight of the initial husk was added to make a diluted slurry with a solid content concentration of 123 g / L, and mixed and stirred for 10 minutes. The diluted slurry was introduced into a wet cyclone, and 18.1 L of the coarse slurry was classified on the underflow side, and 59.4 L of the fine slurry was classified on the overflow side. At this time, the 50% particle size of the coarse slurry was 442 μm, and the 50% particle size of the fine slurry was 11 μm.
Washing water having an amount of 4 times the initial burning husk weight was added to the coarse slurry and mixed and stirred for 10 minutes to obtain a coarse diluted slurry having a solid content concentration of 112 g / L. The coarse diluted slurry is put into a centrifuge and dehydrated, and then the dehydrated cake is washed with washing water having an amount equal to the initial burning husk weight to remove adhering water on the surface, and the coarse washed ash 6 Obtained 5 kg. Water was drained as a coarse filtrate.
On the other hand, the fine slurry is extracted from the wet cyclone and introduced into the mixing and stirring layer, and an anionic polymer flocculant (trade name: Diafloc AP-825B) is added to the stirring tank so that the concentration in the stirring tank is 0.5 ppm. After mixing, the mixture was introduced into a sedimentation separation tank and allowed to stand until the solid content was concentrated to 3.5 times that of the fine particle slurry, so that the solid content was settled to obtain a fine particle concentrated slurry having a solid content concentration of 176 g / L. The secondary supernatant water on the upper side of the fine-grained concentrated slurry was extracted. The chlorine concentration of the secondary supernatant water was 1.1 g / L. The fine-grained concentrated slurry was dehydrated with a filter press, and the dehydrated cake was washed with washing water twice as much as the initial burning husk weight to remove surface adhering water to obtain 3.0 kg of fine-grain washed ash. The water was drained as a fine filtrate.
The recovered coarse ash and fine ash have a chlorine concentration of 0.20 wt% and 0.28 wt%, respectively, and both can be used as cement raw materials.

Example 10
Put 10kg of husks (chlorine concentration 1.6wt%) generated when incinerating industrial waste into a mixing and stirring tank, and put in washing water 5 times the weight of the husks. The solid content concentration is 181g / L. The slurry was prepared as an initial slurry and mixed and stirred for 10 minutes. The solid content concentration after 10 minutes of mixing and stirring was reduced to 173 g / L due to dissolution of soluble components in water. An anionic polymer flocculant (trade name Diaflock AP-825B) was added to and mixed with the slurry so that the concentration in the stirring tank was 1 ppm, and then introduced into the settling tank, so that the solid content concentration was 2.0. The solid content was allowed to settle until it was concentrated twice, and 27.5 L of the upper primary supernatant water was extracted and removed to obtain an initial concentrated slurry. The chlorine concentration of the primary supernatant water was 3.1 g / L.
27.5 L of the initial concentrated slurry was extracted from the sedimentation tank. The solid content concentration was 344 g / L. Washing water in an amount 5 times the weight of the initial husk was added to make a primary dilution slurry with a solid content concentration of 123 g / L, and mixed and stirred for 10 minutes. The primary dilution slurry was introduced into a wet cyclone, and the primary coarse slurry 18.1L was classified on the underflow side, and the primary fine slurry 59.4L was classified on the overflow side. At this time, the 50% particle size of the primary coarse particle slurry was 442 μm, and the 50% particle size of the primary fine particle slurry was 11 μm.
The primary coarse slurry was extracted from the wet cyclone, and washed water having an amount of 4 times the initial burning husk weight was added to form a secondary diluted slurry having a solid concentration of 112 g / L, and mixed and stirred for 10 minutes. The secondary dilution slurry was introduced into a wet cyclone and classified into a secondary coarse slurry 14.5L and a secondary fine slurry 43.5L. At this time, the 50% particle size of the secondary coarse particle slurry was 451 μm, and the 50% particle size of the secondary fine particle slurry was 10 μm. After the secondary coarse slurry is put into a centrifuge and dehydrated, the dehydrated cake is washed with washing water having an amount equal to the initial burning husk weight to remove adhering water on the surface, and the coarse washed ash 4.7 kg was obtained. Water was drained as a coarse filtrate.
On the other hand, the primary fine particle slurry and the secondary fine particle slurry were extracted from each wet cyclone and mixed to obtain a total fine particle slurry. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the total fine particle slurry so that the concentration in the stirring tank was 0.5 ppm, and the mixture was stirred and mixed. The solid content was allowed to settle until it was concentrated to 3.6 times the total fine-particle slurry, to obtain a fine-grain concentrated slurry having a solid content concentration of 168 g / L. The secondary supernatant water on the upper side of the fine-grained concentrated slurry was extracted. The chlorine concentration of the secondary supernatant was 0.73 g / L. The fine-grained concentrated slurry was dehydrated with a filter press, and the dehydrated cake was washed with washing water twice as much as the initial burning husk weight to remove surface adhering water to obtain 4.8 kg of fine-grain washed ash. The water was drained as a fine filtrate.
The recovered coarse-grained ash and fine-grained ash had a chlorine concentration of 0.12 wt% and 0.21 wt%, respectively, which could be used as cement raw materials.

Example 11
A test similar to that of Example 9 was performed, and 42.5 L of secondary supernatant water having a chlorine concentration of 1.1 g / L,
92.8 L of dehydrated washing water having a chlorine concentration of 0.07 g / L was obtained by mixing all of the coarse filtrate and the fine filtrate. 42.5L of the secondary supernatant water and 7.5L of the dehydrated washing water are used as 50L of the initial slurry washing water, 50L of the dehydrated washing water is used as the washing water 50L of the diluted slurry, and 35.3L of the dehydrated washing water is diluted with coarse particles. Except for reusing as a part of 40 L of slurry washing water, 10 kg of husk (chlorine concentration: 1.6 wt%) was treated in the same manner as in Example 9, and 6.5 kg of coarse ash and 3.0 kg of fine ash Got. The recovered coarse-grained ash and fine-grained ash had a chlorine concentration of 0.29 wt% and 0.39 wt%, respectively, which could be used as cement raw materials.

Example 12
The same test as in Example 10 was performed, and 74.4 L of secondary supernatant water having a chlorine concentration of 1.1 g / L,
60.2L of dehydrated washing water having a chlorine concentration of 0.08 g / L was obtained by mixing all of the coarse and fine filtrates. The secondary supernatant water 50L is used as the initial slurry cleaning water 50L, the dehydrated cleaning water 24.4L and the dehydrated cleaning water 25.6L are used as the diluted slurry cleaning water 50L, and the dehydrated cleaning water 34.6L is used as the coarse diluted slurry. Except for reusing as a part of 40L of washing water, 10kg of husk (chlorine concentration 1.6wt%) was treated in the same manner as in Example 10 to obtain 4.7kg of coarse ash and 4.8kg of fine ash. Obtained. The recovered coarse-grained ash and fine-grained ash had a chlorine concentration of 0.20 wt% and 0.39 wt%, respectively, which could be used as cement raw materials.

[Comparative Example 1]
10kg of dust (chlorine concentration 13wt%) generated when industrial waste is incinerated is put into a mixing and stirring tank, 10 times the amount of dust is added to washing water, and an initial slurry with a solid content of 95g / L And mixed and stirred for 10 minutes. The solid concentration after mixing and stirring for 10 minutes was 60 g / L. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the slurry so that the concentration in the stirring tank would be 1 ppm, mixed and then introduced into the settling tank, so that the solid content concentration was 4.3 times. The solid content was allowed to settle until it was concentrated to an initial concentrated slurry. 80.4 L of the primary supernatant water on the upper side of the initial concentrated slurry was extracted and removed. The chlorine concentration of the primary supernatant water was 13.4 g / L.
The initial concentrated slurry was extracted from the sedimentation tank, and washed water of 5 times the initial dust weight was added to make a primary diluted slurry with a solid content concentration of 84 g / L, and mixed and stirred for 10 minutes. An anionic polymer flocculant (trade name: Diafloc AP-825B) was added to the primary dilution slurry so that the concentration in the stirring tank would be 1 ppm, mixed and then introduced into the sedimentation tank, where the solid content concentration was the primary dilution. The slurry was allowed to stand until it was concentrated to 2.9 times the slurry, and the solid content was allowed to settle to a primary concentrated slurry. The secondary supernatant water on the upper side of the primary concentrated slurry was extracted and removed. The chlorine concentration of the secondary supernatant water was 3.7 g / L.
Further, the primary concentrated slurry was extracted from the sedimentation tank, and washed water of 4 times the initial dust weight was added to obtain a secondary diluted slurry with a solid content concentration of 96 g / L, and mixed and stirred for 10 minutes. The secondary concentrated slurry was dewatered, and the dewatered cake was washed with washing water 3 times the initial dust weight, and the surface adhering water was removed to obtain 6.3 kg of washing ash. The chlorine concentration of the washed ash was 0.60 wt%, and the chlorine concentration was high, which was not preferable as a cement raw material.

[Comparative Example 2]
10kg of dust (chlorine concentration 13wt%) generated when industrial waste is incinerated is put into a mixing and stirring tank, 10 times the amount of dust is added to washing water, and an initial slurry with a solid content of 95g / L And mixed and stirred for 10 minutes. The solid concentration after mixing and stirring for 10 minutes was 60 g / L. The slurry was dewatered, and the dewatered cake was washed with washing water 12 times the initial dust weight, and the surface adhering water was removed to obtain 6.3 kg of washing ash. The chlorine concentration of the washed ash was 1.1 wt%, and the chlorine concentration was high, which was not preferable as a cement raw material.

[Comparative Example 3]
Coarse-grained washed ash 4.3 kg and fine-grained washed ash 2.0 kg were obtained in the same manner as in Example 2 except that a wet sieve (screen opening of 32 μm) was used instead of the wet cyclone. The recovered coarse-grained ash and fine-grained ash had a chlorine concentration of 0.58 wt% and 0.60 wt%, respectively, and the chlorine concentration was high, which was undesirable as a cement raw material.

[Comparative Example 4]
In the sedimentation separation, 3.0 kg of coarse-grained washed ash and 3.3 kg of fine-grained washed ash were obtained in the same manner as in Example 2 except that the anionic polymer flocculant was not used. The initial slurry was allowed to stand until the solid content concentration was concentrated 1.5 times, and the total fine-grain slurry was allowed to stand until the solid content concentration was concentrated 1.5 times. The recovered coarse-grained ash and fine-grained ash have a chlorine concentration of 0.55 wt% and 0.71 wt%, respectively.

  Table 1 shows the processing results of Examples 1-12 and Comparative Examples 1-4. In Table 1, the solid content concentration of the initial slurry is the concentration (g / L) after the soluble component after stirring is dissolved. The concentration ratio of the initial concentrated slurry is the ratio (B / A) of the solid content concentration B of the initial concentrated slurry to the solid content concentration A of the initial slurry. The 50% particle size is a particle size indicating 50% in the distribution curve of the cumulative weight ratio of the volume particle size distribution of the particles. The concentration ratio of the fine-grained concentrated slurry is the ratio (D / C) of the solid content concentration D of the fine-grained concentrated slurry to the solid content concentration C of the fine-grained slurry. However, only Comparative Example 1 shows the ratio (3.0 times) of the solid concentration of the primary concentrated slurry to the solid concentration of the primary diluted slurry. The water used for the dewatering and washing was subjected to the classification operation, and 10 L was used for washing and dewatering of the coarse-grained washing ash, and 20 L was used for washing and dewatering of the fine-grained washing ash. In Example 3, Example 4, Example 11, and Example 12, the secondary supernatant water and the dehydrated washing water in which the whole amount of the coarse filtrate and the fine filtrate were mixed were reused to repeatedly perform desalting treatment. did.

  Table 2 shows the rate of chlorine transfer to the primary and secondary supernatants in Examples 1 to 12 and Comparative Examples 1 to 4, and the chlorine reduction rate of each washing ash. Chlorine transfer rate is the proportion of the amount of chlorine that was leached out of the supernatant, extracted and removed, and discharged out of the system, out of the amount of chlorine originally contained in the chlorine-containing ash at the start of treatment. It is. The reduction ratio of chlorine is the ratio of the amount of chlorine in each washed ash after treatment to the amount of chlorine originally contained in the chlorine-containing ash at the start of treatment.

  As shown in Table 1 and Table 2, according to the desalting method of the present invention, a high desalting effect is obtained by a combination of removal of chlorine-containing supernatant water by sedimentation separation in the initial concentration step and classification step by a wet cyclone. It is done. The desalted coarse washed ash and fine washed ash can be used as a cement raw material or a fired aggregate raw material. Moreover, the amount of fresh water used can be greatly reduced by reusing secondary supernatant water and dehydrated washing water and repeatedly performing desalting.

Claims (11)

An initial washing step of adding washing water to the chlorine-containing ash to form an initial slurry and leaching chlorine into water; adding a polymer flocculant to the initial slurry to precipitate and separate the aggregated flocs to form an initial concentrated slurry; and An initial concentration step of transferring chlorine of the chlorine-containing ash to the primary supernatant, a classification step of separating the finely divided slurry and the coarse slurry using a wet cyclone after adding the initial concentrated slurry, and further adding the finely divided slurry to A fine particle concentration step of adding a polymer flocculant to precipitate and separate the fine particle flocs to form a fine particle concentrated slurry and transferring chlorine of the fine particles to the secondary supernatant water, and the initial concentration step. Draining and desalinating the primary supernatant water and secondary supernatant water of the fine granule concentration step, and dewatering and washing the fine granule concentrate slurry to recover the desalted fine granule wash ash, and the coarse particles The Desalting method chlorine-containing ash and a step of recovering the Lee dehydrated washed coarse cleaning ash desalted.   Washing water is added to the chlorine-containing ash to form an initial slurry with a solid content concentration of 30 to 300 g / L, and a polymer flocculant is added to the initial slurry, so that the solid concentration is concentrated to more than twice that of the initial slurry. 2. The chlorine-containing ash desalting according to claim 1, wherein the chlorine-containing ash is separated into slurry and primary supernatant water, and 40 to 90% of the chlorine content contained in the chlorine-containing ash is transferred to the primary supernatant water and removed from the system. Processing method. Washing water is added to the initial concentrated slurry to form a diluted slurry having a solid content concentration of 10 to 150 g / L. The diluted slurry is introduced into a wet cyclone, and coarse particles containing coarse particles having a 50% particle size of 30 μm to 1000 μm. The method for desalinating chlorine-containing ash according to claim 1 or 2, wherein the slurry is classified into a slurry and a fine slurry containing fine particles having a 50% particle diameter of less than 30 µm .   A fine particle slurry is added to a polymer flocculant to precipitate and separate the fine ash, and the solid content is separated into a fine particle concentrated slurry in which the concentration is more than twice that of the fine particle slurry, and the secondary supernatant water, The secondary supernatant water is transferred to 5 to 60% of the amount of chlorine contained in the chlorine-containing ash and removed from the system, and the fine-grained concentrated slurry is recovered. A method for desalinating chlorine-containing ash.   The collected fine-grained concentrated slurry is dewatered and washed, and the fine-grained washed ash with the chlorine content contained in the chlorine-containing ash at the start of treatment reduced to 1/2 to 1/60 is collected. A method for desalinating chlorine-containing ash according to any one of the above.   The coarse-grain slurry is washed and solid-liquid separated, and the coarse-grain wash ash with the chlorine content contained in the chlorine-containing ash at the start of treatment reduced to 1/2 to 1/100 is recovered. A method for desalinating chlorine-containing ash according to any one of the above.   The method for desalinating chlorine-containing ash according to any one of claims 1 to 6, wherein the step of introducing the diluted slurry into a wet cyclone and classifying the slurry into a fine slurry and a coarse slurry is performed a plurality of times.   The diluted slurry is introduced into a wet cyclone and classified into a primary fine particle slurry and a primary coarse particle slurry. Washing water is added to the primary coarse particle slurry to obtain a secondary diluted slurry having a solid content concentration of 10 to 150 g / L. The secondary dilution slurry is again introduced into the wet cyclone and classified into a secondary fine slurry and a secondary coarse slurry, and the secondary fine slurry and the primary fine slurry are mixed to form a total fine slurry. The method for desalinating chlorine-containing ash according to claim 7, wherein a polymer flocculant is added to the fine particle slurry, and the fine particles are settled to obtain a fine particle concentrated slurry.   The method for desalinating chlorine-containing ash according to any one of claims 1 to 8, wherein the coarse-grained ash and the fine-grained ash are collected and used as a cement raw material.   Treats main ash and fly ash generated from the intermediate treatment of municipal waste, burning husks and soot generated from the intermediate treatment of industrial waste, excavated ash generated from reclamation work at landfill sites, or chlorine bypass dust generated from cement factories The method for desalinating chlorine-containing ash according to any one of claims 1 to 9. Means for adding washing water to chlorine-containing ash to form an initial slurry, leaching chlorine into water, means for stirring the initial slurry, means for adding a polymer flocculant to the initial slurry, and initializing the aggregated floc by settling and separation A means for forming a concentrated slurry and transferring chlorine from the chlorine-containing ash to the primary supernatant water to separate it from the supernatant water; a means for removing the supernatant water from the system; and a dilution slurry by adding washing water to the initial concentrated slurry A wet cyclone for classifying the diluted slurry into a fine-grained slurry and a coarse-grained slurry, and adding a polymer flocculant to the fine-grained slurry to precipitate and separate the fine grains to form a fine-grained concentrated slurry. means for separating the upper supernatant water by migrating grain chlorine above supernatant water, means for recovering fine cleaning ash desalted dehydrated washed said sub grain concentrated slurry, desalted and dehydrated washing the coarse slurry Shi Further comprising means for recovering the coarse cleaning ash desalination apparatus chlorine-containing ash, characterized in.

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