JP6279664B2 - Fly ash treatment method and fly ash treatment apparatus - Google Patents

Description

  The present invention relates to a fly ash cleaning method, a processing method, a cleaning apparatus, and a processing apparatus, and more particularly to a cleaning method, a processing method, a cleaning apparatus, and a processing apparatus for fly ash containing radioactive cesium.

  In recent years, there is a case where radioactive cesium is contained in fly ash generated by incineration of sludge, garbage, etc., and it is necessary to clean such fly ash. As a method for cleaning fly ash containing radioactive cesium, for example, there are the following techniques disclosed in Non-Patent Document 1 and Non-Patent Document 2. Moreover, as a method for washing fly ash containing chlorine, for example, there is the following technique disclosed in Patent Document 1.

  Specifically, Patent Document 1 discloses a technique for elution of a substance to be removed by performing elution, solid-liquid separation, and dehydration three times, respectively, as a fly ash cleaning system containing a chlorine compound.

  Non-Patent Document 1 discloses a technique in which fly ash and water are supplied to a dissolution tank and then supplied to a cleaning device, and a dehydrated cake is generated by a filter press as an ash cleaning method. .

  Non-Patent Document 2 discloses a technique for confirming the elution rate by eluting fly ash containing radioactive cesium into a solvent (distilled water).

Japanese Patent No. 4329906

(Germany) National Institute for Environmental Studies, Resource Recycling and Waste Research Center, “Cleaning Technology for Soot and Dust Exceeding 8,000 Bq / kg”, [online] March 17, 2012, Ministry of the Environment, [June 8, 2012] Day search], Internet <URL: http://www.env.go.jp/jishin/attach/haikihyouka_kentokai/12-mat_5.pdf> (Germany) National Institute for Environmental Studies, Resource Recycling and Waste Research Center, “Appropriate Waste Disposal from the Viewpoint of Behavior of Radioactive Substances (Technical Data)”, [online] December 2, 2011, [July 2012 Search 12th of March], Internet <URL: http://www.env.go.jp/jishin/attach/haikihyouka_kentokai/10-mat_3.pdf>

In the ash cleaning method disclosed in Non-Patent Document 1, the dissolution tank, the cleaning device, and the filter press are contaminated by radioactive cesium.
In the fly ash cleaning method disclosed in Patent Document 1, elution, solid-liquid separation, and dehydration are performed three times. For this reason, the efficiency of washing fly ash is poor.
Non-Patent Document 2 discloses that the elution rate in one elution operation is 47%, and the elution rate in two elution operations is 60%. When the elution rate is low, the fly ash cannot be washed sufficiently. In order to increase the elution rate in order to sufficiently wash fly ash, elution, solid-liquid separation, and dehydration must be performed many times. Non-Patent Document 2 discloses that the elution rate is 78% even after five elution operations. For this reason, the efficiency of washing fly ash is poor.

  In view of the above problems, the present invention can reduce the equipment contaminated by radioactive cesium when washing or treating fly ash, and improve the efficiency of washing, and the fly ash washing method and treatment method It is an object of the present invention to provide a cleaning device and a processing device.

  The method for washing fly ash according to the present invention includes a step of eluting radioactive cesium by mixing fly ash containing radioactive cesium and water, and an eluate obtained in the step of elution is subjected to solid-liquid separation using a filter press. And a step of supplying water to the dehydrated cake in the filter press obtained in the solid-liquid separation step, and a dehydrated cake containing water in the supplying step is solid-liquid separated by the filter press. In the supplying step, water having a volume not less than 3 times and not more than 9 times the volume of the dehydrated cake is supplied.

  The cleaning apparatus for fly ash according to the present invention comprises a mixing tank in which fly ash containing radioactive cesium and water are mixed to form an eluate by eluting the radioactive cesium, and an eluate obtained in the mixing tank. A filter press for solid-liquid separation and a supply unit for supplying water having a volume of 3 to 9 times the volume of the dehydrated cake to the dehydrated cake in the filter press.

Non-Patent Document 2 discloses that about 80% of the radioactive cesium is present as cesium chloride that is easily soluble in water, and about 20% is present as a cesium compound that is insoluble or difficult to dissolve in water. Has been. However, the elution rate in one elution operation is 47%, the elution rate in two elution operations is 60%, the elution rate is low in one or two elution operations, and the number of elution operations is further increased. If it is not overlapped, it cannot be eluted up to 80%. Therefore, conventionally, in order to sufficiently dissolve radioactive cesium in fly ash in water, it has been considered to repeat the elution operation three times or more, or to provide a secondary cleaning device, or both.
Then, in order to dissolve radioactive cesium in fly ash in water, by supplying water having a volume of 3 to 9 times to the dehydrated cake in which the eluate is compressed with a filter press, The present inventors have found that the radioactive cesium in the fly ash can be sufficiently dissolved in water. When the volume of supplied water is less than 3 times the volume of dehydrated cake, radioactive cesium is not sufficiently eluted, and when the volume of supplied water exceeds 9 times the volume of dehydrated cake, the amount of supplied water is It becomes excessive, the amount of the separated liquid separated by the filter press increases, and the efficiency of the treatment of the separated liquid becomes worse.
In this way, since water having a volume of 3 to 9 times the volume of the dehydrated cake is supplied to the dehydrated cake in the filter press, the equipment required to dissolve the radioactive cesium in the fly ash in water, Even if the washing device is omitted and only the mixing tank for mixing fly ash and water is used, the radioactive cesium in the fly ash can be sufficiently dissolved in water. For this reason, even if a washing device arranged between the mixing tank and the solid-liquid separation device is omitted, the fly ash can be washed sufficiently.
As described above, the fly ash cleaning method and cleaning apparatus of the present invention can reduce equipment contaminated by radioactive cesium when cleaning or processing fly ash, and improve the cleaning efficiency.

  Here, in this specification, the mixing tank means a tank in which fly ash and water are mixed and dissolved. The cleaning device of Non-Patent Document 1 means a device that applies a shearing force with air to a solution in which fly ash is dissolved to perform cleaning. That is, the mixing tank of the present invention is substantially the same as the dissolution tank of Non-Patent Document 1, and differs from the cleaning apparatus of Non-Patent Document 1 in that no shearing force is given by air.

  The fly ash treatment method of the present invention includes a step of washing fly ash by the fly ash washing method, and supplying a separation liquid obtained by the solid-liquid separation to a reverse osmosis (RO) membrane device, followed by filtration. A step of generating permeated water and concentrated water by the treatment, and a step of adsorbing radioactive cesium in the concentrated water to the adsorbent.

  The fly ash treatment apparatus of the present invention is a reverse osmosis (RO) membrane device that is supplied with the separation liquid obtained by the fly ash cleaning apparatus and the solid-liquid separation apparatus and generates permeate and concentrated water by filtration. And an adsorption tower including an adsorbent that adsorbs radioactive cesium in the concentrated water.

  According to the fly ash treatment method and treatment apparatus of the present invention, concentrated water containing radioactive cesium can be generated by filtration of radioactive cesium in the RO membrane device, and the radioactive cesium in the concentrated water is adsorbed by the adsorbent. be able to. For this reason, radioactive cesium contained in fly ash can be made to adsorb | suck to an adsorbent. In this way, the fly ash treatment method and treatment apparatus of the present invention efficiently removes radioactive cesium in fly ash even if equipment such as a cleaning device disposed between the mixing tank and the solid-liquid separation device is omitted. Can be processed well. Accordingly, when washing or treating fly ash, equipment contaminated by radioactive cesium can be reduced, and washing efficiency can be improved.

  As described above, according to the present invention, when the fly ash is washed or processed, it is possible to reduce equipment contaminated by radioactive cesium and improve the washing efficiency, A processing method, a cleaning apparatus, and a processing apparatus can be provided.

It is a schematic diagram which shows the washing | cleaning method, processing method, washing | cleaning apparatus, and processing apparatus of fly ash in embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a fly ash cleaning apparatus 1 and a processing apparatus 10 according to an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the fly ash cleaning device 1 according to the present embodiment includes a mixing tank 2, a solid-liquid separation device 3, and a supply unit 4. The fly ash treatment apparatus 10 in the present embodiment includes a cleaning apparatus 1, an adjustment tank 11, a precipitation tank 12, a turbidity apparatus 13, a pressurizing unit 14, a reverse osmosis (RO) membrane apparatus 15, An adsorption tower 16, a capture unit 17, a shielding unit 18, a treated water tank 19, and a solidifying device 20 are provided.

  The mixing tank 2 is supplied with fly ash A containing radioactive cesium and water B, and the fly ash A and water B are mixed to form an eluate. The mixing tank 2 dissolves radioactive cesium in the fly ash A in water B. The water B is not particularly limited. For example, tap water, industrial water, pure water, ground water, reprocessed water for various types of waste water, and the like can be used.

  The mixing tank 2 may have a stirring member for mixing and stirring the supplied fly ash A and water B. Moreover, the mixing tank 2 may contain the some tank.

  The mixing tank 2 is a tank in which the fly ash A and the water B are mixed and dissolved, and does not give a shearing force with air to the liquid in which the fly ash A is dissolved.

  The solid-liquid separation device 3 is connected to the mixing tank 2, and no devices such as a cleaning device, a classification device, and a dehydration device are disposed between the solid-liquid separation device 3 and the mixing tank 2. That is, only the member which connects them is arrange | positioned between the mixing tank 2 and the solid-liquid separator 3, and the pump for transferring the eluate formed in the mixing tank 2 to the solid-liquid separator 3 A storage tank or the like may be arranged.

  The solid-liquid separation device 3 is a filter press that solid-liquid separates the eluate obtained in the mixing tank 2. The solid-liquid separation device 3 performs solid-liquid separation of the eluate into a dehydrated cake and a separated liquid containing radioactive cesium, and the dehydrated cake (eluate) supplied with water from the supply unit 4 described later is dehydrated cake. And solid-liquid separation into a separation liquid containing radioactive cesium. The dehydrated cake obtained by dehydrating the dehydrated cake supplied with water from the supply unit 4 is washed fly ash (washed fly ash C).

  The filter press is not particularly limited. For example, a filter press with a filter cloth on a filter plate with holes in the center of metal or resin unevenness, and the eluate is centered on the filter plate with a pump or the like. Pressurized and pressed from the hole, only water (separated liquid) is discharged outside the filter cloth in the gap between the two filter plates, and a dehydrated cake is formed between the filter plates (between the filter cloth and the filter cloth). It is what is done.

  The supply unit 4 supplies water having a volume of 3 to 9 times, preferably 3 to 8 times the volume of the dehydrated cake to the dehydrated cake in the solid-liquid separator 3. The supply unit 4 may be configured to supply water from the outside of the processing device 10 to the solid-liquid separation device 3, and the permeated water D discharged by the RO membrane device 15 described later is supplied to the solid-liquid separation device 3. It may be configured to supply to. In addition, when the water supplied from the supply part 4 is introduce | transduced from the exterior of the processing apparatus 10, tap water, industrial water, pure water, ground water, reprocessing water of various waste_water | drain etc. can be utilized, for example.

  The adjustment tank 11 is connected to a separation liquid discharge unit of the solid-liquid separation device 3 and stores a separation liquid containing radioactive cesium generated by the solid-liquid separation device 3. The adjustment tank 11 may include a plurality of tanks.

  The sedimentation tank 12 is connected to the adjustment tank 11, and agglomerates and precipitates coarse solids (coarse solids than separated by the turbidizer 13) in the separation liquid when solids are mixed in the separation liquid. The precipitation tank 12 reduces coarse solids in the separated liquid. The sedimentation tank 12 may include a plurality of tanks.

  The turbidity removal device 13 is connected to the sedimentation tank 12 and is used for filtering the separated liquid in which coarse solids are reduced. The turbidity removal device 13 is coarser than the RO membrane, that is, has impurities ( For example, it is a pretreatment device for the RO membrane device 15. The turbidity removing device 13 is, for example, sand filtration.

  The pressurizing unit 14 is connected to the turbidity device 13 and pressurizes the separated liquid from which coarse impurities discharged from the turbidity device 13 are removed to an osmotic pressure or higher. The pressurizing unit 14 is, for example, a high pressure pump.

  The RO membrane device 15 is connected to the pressurizing unit 14, is supplied with a pressurized separation liquid, and generates permeated water D and concentrated water by filtration. The permeated water D is water that has passed through the RO membrane, and the concentrated water is water that does not pass through the RO membrane and contains radioactive cesium. In this RO membrane device 15, the permeated water D from which radioactive cesium has been removed and the concentrated water in which the radioactive cesium contained in the fly ash remains can be obtained by filtration with an RO membrane.

  The RO membrane device 15 includes, for example, an RO membrane and a pressure vessel that accommodates the RO membrane. The RO membrane is configured not to transmit radioactive cesium.

  In addition, the processing apparatus 10 may be provided with one set of the pressurizing part 14 and the RO membrane apparatus 15, and may be provided with a plurality of sets of the pressurizing part 14 and the RO membrane apparatus 15. When the processing apparatus 10 includes a plurality of sets of pressure units 14 and RO membrane apparatuses 15, they may be arranged in parallel or in series, but are preferably arranged in series.

  The use of the permeated water D obtained by the RO membrane device 15 is not particularly limited, but is preferably configured to be supplied to the solid-liquid separation device 3. For example, as shown by the dotted line connecting the permeated water D and the solid-liquid separation device 3 in FIG. 1, the permeate discharge unit of the RO membrane device 15 and the solid-liquid separation device 3 are connected by a pipe or the like. 4 and the permeated water D is used for washing fly ash. Moreover, you may use the permeated water D as the water B which wash | cleans the fly ash A, for example. Thus, it is preferable that the processing apparatus 10 is configured to circulate water generated in the processing apparatus 10 in the processing apparatus 10.

The adsorption tower 16 is connected to the concentrated water discharge part of the RO membrane device 15, and adsorbs radioactive cesium in the concentrated water to generate treated water. The adsorption tower 16 accommodates therein an adsorbent capable of adsorbing radioactive cesium. The adsorbent is not particularly limited as long as it can adsorb radioactive cesium, and may adsorb non-radioactive cesium or the like. Such adsorbents are, for example, bitumen and zeolite, and are preferably bitumen. Bitumen is also called ferrocyanide (C ₁₈ Fe ₇ N ₁₈ ) or Prussian blue, and includes materials derived from bitumen such as bitumen-supported products and bitumen granules.

  The capture unit 17 captures the adsorbent discharged from the adsorption tower 16. Although the capture part 17 is not specifically limited, For example, a UF film | membrane, a precipitation apparatus, etc. can be used and it is preferable to use a UF film | membrane from a viewpoint with high capture property.

  The shielding unit 18 surrounds the adsorption tower 16 and the capturing unit 17. The shielding part 18 is, for example, concrete, and is configured so that radiation does not leak from the inside to the outside.

  The treated water tank 19 is connected to the capture unit 17 and stores treated water from which the adsorbent has been removed by the capture unit 17. The treated water stored in the treated water tank 19 is reduced in radioactive cesium, but has a salt content.

  The solidification device 20 is connected to the treated water tank 19 and separates into treated water E and salinity F with reduced salinity. The solidification device 20 is, for example, an evaporation device. The obtained treated water E, like the permeated water D, may be supplied to the solid-liquid separation device 3 as washing of the fly ash A, or may be used as the water B. When the treated water E is supplied to the solid-liquid separator 3, it may be used as washing water for the eluate supplied from the mixing tank 2 to the solid-liquid separator 3, but dehydrated by the solid-liquid separator 3. It is preferable to use it as washing water for the dehydrated cake obtained. Treated water E and permeated water D are water with few impurities and have a quality of pure water, so that they can be used as rinsing water for the solid-liquid separation device 3 to use more cesium than using tap water or industrial water. Can be efficiently eluted.

  Subsequently, a cleaning method and a processing method of fly ash in the present embodiment will be described. The fly ash cleaning method and the processing method in the present embodiment are performed using the fly ash cleaning apparatus 1 and the processing apparatus 10 shown in FIG.

  First, fly ash A containing radioactive cesium and water B are supplied to the mixing tank 2, and the fly ash A and water B are mixed in the mixing tank 2 to form an eluate. In this step, radioactive cesium in fly ash A is dissolved in water B.

  Next, the eluate obtained in the above step is subjected to solid-liquid separation. In other words, the eluate obtained in the mixing tank 2 is supplied to the solid-liquid separator 3 without passing through other equipment such as a cleaning device. In other words, after the step of forming the eluate, a step of solid-liquid separation is performed without performing other steps such as a washing step and a classification step. In this solid-liquid separation step, the eluate is solid-liquid separated using a filter press. By this process, it is separated into a dehydrated cake as a solid content and a separation liquid containing radioactive cesium as a liquid content.

  Next, water is supplied to the dehydrated cake in the filter press which is the solid-liquid separation device 3 obtained in the solid-liquid separation step. In this step, water having a volume of 3 to 9 times, preferably 3 to 8 times the volume of the dehydrated cake is supplied. When the volume of water is more than 3 times the volume of the dehydrated cake, 80% or more of radioactive cesium is eluted. Even if the volume of water with respect to the volume of the dehydrated cake is more than 9 times or less than 9 times, the difference in elution amount of radioactive cesium is the same, so the amount of washing water can be reduced by making it 9 times or less. Since the amount of the separation liquid can be reduced, the processing efficiency of the separation liquid containing radioactive cesium can be improved.

  Next, the dehydrated cake containing water in the step of supplying water is subjected to solid-liquid separation by the solid-liquid separation device 3. Thereby, it isolate | separates into the wash liquid ash (washing fly ash C) which is a dewatering cake, and the isolation | separation liquid containing the radioactive cesium as a liquid component. After dehydration is completed, the filter press filter plate is opened and the dehydrated cake is discharged.

  By carrying out the above steps, radioactive cesium in the fly ash A can be reduced, so that the fly ash A can be washed. When processing the radioactive cesium in the fly ash A, the following processes are implemented following the said process.

The separation liquid containing radioactive cesium obtained by solid-liquid separation is transferred to the adjustment tank 11.
Next, the separation liquid stored in the adjustment tank 11 is transferred to the precipitation tank 12, and when the solid content is contained in the separation liquid, the solid matter in the separation liquid is aggregated and precipitated.

  Next, the separation liquid that has been subjected to the precipitation treatment in the precipitation tank 12 is filtered by the turbidity device 13. By this filtration, coarse impurities such as solid substances in the separated liquid that have not been removed in the precipitation tank 12 can be removed.

  Next, the separation liquid from which coarse impurities have been removed by the turbidizer 13 is pressurized by the pressure unit 14. The pressure applied to the separation liquid is not particularly limited, but a pressure necessary for obtaining the permeated water D from which radioactive cesium has been removed by the RO membrane device 15 is applied.

  Next, the separation liquid pressurized by the pressurization unit 14 is supplied to the RO membrane device 15 and separated into permeated water D and concentrated water by filtration using the RO membrane. Through this step, permeated water D from which radioactive cesium has been removed and concentrated water in which radioactive cesium contained in fly ash remains are generated.

  In addition, the pressurizing unit 14 and the RO membrane device 15 may be one stage or a plurality of stages. In the case of two stages, the separation liquid pressurized by the first stage pressurizing unit 14 is filtered by the first stage RO membrane device 15, and the resulting permeate is added by the second stage pressurizing part. It is preferable that the permeated water pressurized and pressurized is filtered by the second stage RO membrane device, and the water that has permeated the second stage RO membrane device is used as the permeated water D.

  Although the permeated water D may be discharged to the outside of the processing apparatus 10, it is preferable to employ a closed system that circulates water generated in the processing apparatus 10 into the processing apparatus 10. In the closed system, the permeated water D may be supplied as a cleaning liquid to the filter press or used as the water B.

  Next, radioactive cesium in the concentrated water is adsorbed on the adsorbent. In this step, the concentrated water is supplied to the adsorption tower 16 and the radioactive cesium is adsorbed by an adsorbent such as bitumen or zeolite accommodated in the adsorption tower 16. Thereby, the radioactive cesium contained in the fly ash can be processed. The adsorbent on which the radioactive cesium is adsorbed is subjected to a predetermined waste treatment.

  Next, the adsorbent and the like discharged from the adsorption tower 16 are captured. In this step, when the adsorbent containing radioactive cesium is discharged from the adsorption tower, the adsorbent is captured by a capture means such as a UF membrane.

  The step of adsorbing to the adsorbent and the step of capturing the adsorbent are performed in the shielding unit 18 that shields radiation inside. Thereby, it can suppress that radioactive cesium leaks outside during implementation of the above-mentioned process.

  Next, the treated water from which the adsorbent has been removed by the capture unit 17 is accommodated in the treated water tank 19. The treated water stored in the treated water tank 19 is reduced in radioactive cesium, but has a salt content.

  Next, the salt content in the treated water is separated by a solidifying device 20 such as an evaporator. Thereby, the treated water E with reduced salinity and the salinity F can be generated. The treated water E may be supplied to the solid-liquid separator 3 or may be used as the water B.

  As described above, the fly ash cleaning method of the present embodiment is a step of eluting radioactive cesium by mixing fly ash containing radioactive cesium and water, and an eluate obtained in the step of eluting In a solid-liquid separation with a filter press (solid-liquid separation device 3), a step of supplying water to the dehydrated cake in the filter press obtained in the step of solid-liquid separation, A step of solid-liquid separation of the contained dehydrated cake with a filter press, and in the supplying step, water having a volume of 3 to 9 times the volume of the dehydrated cake is supplied.

  Further, the fly ash cleaning apparatus 1 of the present embodiment is a mixture tank 2 that mixes fly ash A containing radioactive cesium and water B, and elutes radioactive cesium to form an eluate, and this A filter press (solid-liquid separator 3) for solid-liquid separation of the eluate obtained in the mixing tank 2 and a dehydrated cake in the filter press are supplied with water having a volume of 3 to 9 times the volume of the dehydrated cake. And a supply unit 4.

According to the fly ash washing method and washing apparatus in the present embodiment, fly ash A is supplied by supplying water having a volume of 3 to 9 times to a dehydrated cake in which the eluate is compressed by a filter press. More than 80% of radioactive cesium contained in fly ash by one elution operation in water, one dehydration operation of eluate with filter press, and one rinse operation with filter press Can be recovered as a separation liquid. For this reason, the efficiency of washing fly ash can be improved.
Also, by omitting the cleaning device, which is a device required for dissolving radioactive cesium in fly ash in water, even in the mixing tank 2 that mixes fly ash and water, Since water having a volume not less than 3 times and not more than 9 times the volume of the dehydrated cake can be supplied and the radioactive cesium can be sufficiently eluted, the radioactive cesium in the fly ash A can be sufficiently dissolved in water. For this reason, even if the washing | cleaning apparatus arrange | positioned between the mixing tank 2 and the solid-liquid separation apparatus 3 is abbreviate | omitted, the fly ash A can fully be wash | cleaned.
Furthermore, the washing effect is further increased by circulating the washing water through the dehydrated cake for a certain period of time.
By omitting the cleaning device, the power required for the cleaning device can be omitted, so that the cleaning efficiency can be improved.
From the above, the fly ash cleaning method and the cleaning apparatus 1 according to the present embodiment can reduce equipment contaminated by radioactive cesium and improve the cleaning efficiency when cleaning or processing fly ash. .

  The fly ash treatment method of the present embodiment includes a step of washing fly ash A by the above-described fly ash washing method, and supplying a separation liquid obtained by the above solid-liquid separation to the RO membrane device 15 to perform a filtration treatment. A step of generating permeated water D and concentrated water, and a step of adsorbing radioactive cesium in the concentrated water to the adsorbent.

  The fly ash treatment apparatus 10 of the present invention is supplied with the separation liquid obtained by the fly ash washing apparatus 1 and the solid-liquid separation apparatus 3, and the RO membrane apparatus 15 that generates permeate D and concentrated water by filtration treatment. And an adsorption tower 16 containing an adsorbent for adsorbing radioactive cesium in the concentrated water.

  According to the fly ash treatment method and the treatment apparatus 10 in the present embodiment, the concentrated cesium-containing concentrated water can be generated by the radioactive cesium filtration process in the RO membrane device 15, and the radioactive cesium in the concentrated water is adsorbed. Can be adsorbed on the material. For this reason, since the radioactive cesium contained in the fly ash A can be made to adsorb | suck to an adsorbent, the radioactive cesium contained in the fly ash A can be processed. As described above, the fly ash treatment method and the treatment apparatus 10 according to the present embodiment can be used even if a device such as a cleaning device disposed between the mixing tank 2 and the solid-liquid separation device 3 is omitted. A can be processed efficiently. Therefore, when processing fly ash A, while being able to reduce the apparatus contaminated with radioactive cesium, the efficiency of the treatment of fly ash A can be improved.

  In the fly ash treatment method in the present embodiment, preferably, permeate D obtained in the step of generating permeate and concentrated water is supplied to the filter press.

  In the fly ash treatment method of the present embodiment, the filter press is preferably configured to be supplied with the permeate D obtained by the RO membrane device 15.

  Thereby, since the permeated water D obtained by filtration using the RO membrane device 15 can be used as the washing water in the filter press, the fly ash A can be washed effectively, and the fly ash treatment method and treatment The water supplied into the apparatus 10 can be reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  DESCRIPTION OF SYMBOLS 1 Cleaning apparatus, 2 Mixing tank, 3 Solid-liquid separation apparatus, 4 Supply part, 10 Processing apparatus, 11 Adjustment tank, 12 Precipitation tank, 13 Turbidity removal apparatus, 14 Pressurization part, 15 RO membrane apparatus, 16 Adsorption tower, 17 Capture unit, 18 shielding unit, 19 treated water tank, 20 solidification device, A fly ash, B water, C washed fly ash, D permeated water, E treated water, F salt content.

Claims (4)

Mixing the fly ash containing radioactive cesium and water to elute the radioactive cesium;
A step of obtaining a first separation liquid by solid-liquid separation of the eluate obtained in the elution step with a filter press;
Supplying water to the dehydrated cake in the filter press obtained in the step of obtaining the first separation liquid;
A step of obtaining a second separated liquid by solid-liquid separation of the dehydrated cake containing water in the supplying step with the filter press;
A step of adsorbing radioactive cesium in the first separation liquid or the second separation liquid to an adsorbent to obtain treated water,
In the supplying step, water having a volume of 3 to 9 times the volume of the dehydrated cake is supplied,
Further comprising the step of separating the treated water into treated water with reduced salinity and salinity using a solidification device;
A method for treating fly ash, wherein the treated water with reduced salinity is used as at least one of the water in the eluting step and the water in the supplying step. A step of supplying the first separation liquid or the second separation liquid to a reverse osmosis membrane device and generating permeated water and concentrated water by filtration;
Wherein in the step of obtaining a treated water to obtain the treated water by adsorbing radioactive cesium of the concentrate water to the adsorbent treatment method of fly ash according to claim 1. Mixing fly ash containing radioactive cesium and water, and mixing elution liquid by eluting radioactive cesium,
A filter press for obtaining a first separation liquid by solid-liquid separation of the eluate obtained in the mixing tank;
A supply unit for supplying water having a volume of 3 to 9 times the volume of the dehydrated cake to the dehydrated cake in the filter press;
The filter press is configured to obtain a second separated liquid by solid-liquid separation of a dehydrated cake containing water supplied by the supply unit,
An adsorption tower for obtaining treated water by adsorbing radioactive cesium in the first separation liquid or the second separation liquid with an adsorbent;
A solidifying device for separating the treated water into treated water with reduced salinity and salinity;
A fly ash treatment apparatus configured to supply treated water with reduced salinity to at least one of the mixing tank and the filter press. A reverse osmosis membrane device that is supplied with the first separation liquid or the second separation liquid and generates permeated water and concentrated water by filtration;
The fly ash treatment apparatus according to claim 3 , wherein the adsorption tower is configured to obtain the treated water by adsorbing radioactive cesium in the concentrated water with the adsorbent.

Images