JP6560874B2 - Cleaning method of incineration ash - Google Patents

Description

  The present invention relates to a method for cleaning incineration ash, and can be suitably used for, for example, a method for cleaning incineration ash that removes heavy metals contained in incineration ash, particularly lead (Pb).

  For example, in Japanese Patent No. 4834936 (Patent Document 1), the bottom ash of a waste incinerator is brought into contact with an extraction liquid to extract the extraction residue and the extraction waste liquid, and the extraction waste liquid and fly ash are mixed and harmless. An incineration ash treatment apparatus including a detoxification treatment means for carrying out a treatment is described.

  In addition, in Japanese Patent No. 4999904 (Patent Document 2), waste containing lead is added to an aqueous solution containing calcium ions to form a slurry, and the lead component is eluted from the waste into the slurry while stirring the slurry. A waste treatment method is described in which stirring is stopped before the eluted lead component returns to waste, and the slurry is solid-liquid separated into a solid content with a low lead content and a solution with a high lead content. Yes.

Japanese Patent No. 4834936 Japanese Patent No. 4999904

  The incineration ash discharged from the incineration facility contains heavy metals such as lead. In particular, for lead, acceptance standards for final disposal of incineration ash, as well as maintenance standards and abolition standards for leachate generated from the final disposal site have been established. It is necessary to remove or insolubilize before discharging from the incineration facility.

  In recent years, the capacity of the disposal site has become tight due to the difficulty of constructing the final disposal site, so the recycling of incinerated ash greatly contributes to the extension of the life of the existing final disposal site. A problem in the recycling of incineration ash is elution of heavy metals from the incineration ash. That is, in order to further promote the recycling of incinerated ash, it is important to remove heavy metals contained in the incinerated ash in advance.

  Patent Document 1 describes a method for treating incinerated ash using an acid or an alkali. However, this method of eluting lead using an acid or alkali has a higher cost of the drug and requires a large amount of drug compared to a method of eluting lead using an aqueous calcium chloride solution.

  Patent Document 2 describes a method for treating incinerated ash using an aqueous calcium chloride solution. However, in the method of eluting lead using this calcium chloride aqueous solution, 1 to 10 times as much water as incineration ash is required for cleaning, and the amount of drug used increases as the amount of water used for cleaning increases. Therefore, the burden on water treatment by calcium such as generation of scale increases. That is, the amount of water and chemicals used increases, and the processing cost increases accordingly.

  Therefore, the present invention provides a low-cost cleaning method for incineration ash by reducing the amount of water and chemicals supplied to the incineration ash.

  In order to solve the above-mentioned problem, the incinerated ash is washed by watering a calcium compound aqueous solution of less than 1 times the amount of the incinerated ash to the incinerated ash that has been left standing, and then watering water that does not contain calcium ions. The calcium ion concentration of the calcium compound aqueous solution is 1% or more, the liquid-solid ratio obtained by dividing the amount of the calcium compound aqueous solution by the weight of the incineration ash is less than 1.0, and the calcium compound aqueous solution and water not containing calcium ions are Water is intermittently sprinkled from the incineration ash.

  ADVANTAGE OF THE INVENTION According to this invention, the washing method of the low cost incineration ash can be provided by reducing the usage-amount of the water and chemical | medical agent supplied to incineration ash.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a graph which shows the relationship between the form of calcium by a present Example, and the lead concentration in the elution water. It is a graph which shows the relationship between the calcium ion concentration of the calcium chloride aqueous solution by a present Example, and the lead concentration in elution water. It is a graph which shows the relationship between the amount of accumulation leachate by this example, and the electrical conductivity of leachate. It is a graph which shows the relationship between the various washing | cleaning methods by a present Example, the accumulated lead elution amount, and the accumulated lead elution amount per calcium. It is a graph which shows the relationship between the various washing | cleaning methods by a present Example, and the lead concentration in elution water. It is a graph which shows the relationship between the kind of gas to vent by a present Example, and the lead concentration in the elution water. It is the schematic of the washing | cleaning apparatus used for washing | cleaning of the incineration ash by a present Example. It is the schematic of the washing | cleaning apparatus used for washing | cleaning of the incineration ash by the modification 1 of a present Example. It is the schematic of the washing | cleaning apparatus used for washing | cleaning of the incineration ash by the modification 2 of a present Example. It is the schematic of the washing | cleaning apparatus used for washing | cleaning of the incineration ash by the modification 3 of a present Example. It is the schematic of the washing | cleaning apparatus used for washing | cleaning of the incineration ash by the modification 4 of a present Example.

  In the following embodiments, when necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other, and one is the other. There are some or all of the modifications, details, supplementary explanations, and the like.

  Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps) are not necessarily indispensable unless otherwise specified and clearly considered essential in principle. Needless to say.

  In addition, when referring to “consisting of A”, “consisting of A”, “having A”, and “including A”, other elements are excluded unless specifically indicated that only that element is included. It goes without saying that it is not what you do. Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

  In all the drawings for explaining the following embodiments, components having the same function are denoted by the same reference numerals in principle, and repeated description thereof is omitted. Hereinafter, the present embodiment will be described in detail with reference to the drawings.

  FIG. 1 is a graph showing the relationship between the form of calcium and the lead concentration in the elution water according to this example. The elution water was prepared in accordance with Environmental Agency Notification No. 13. That is, an aqueous solution adjusted to have a calcium ion concentration of 5% was added to the incinerated ash, and the mixture was shaken continuously for 6 hours and then allowed to stand, and then a 1.0 μm membrane filter. Elution water was created by filtering with.

As shown in FIG. 1, elution water contains lead in all forms, particularly chloride ([Cl] ⁻ ), nitrate ([NO ₃ ] ⁻ ), and acetate ([CH ₃ COOH] ⁻ ). Has a higher concentration of lead. Hydroxide ([OH] ⁻ ) has a lower lead concentration in the elution water than other forms, but is contained in an aqueous calcium compound solution using an agent that increases the amount used or dissolves calcium hydroxide such as acid. By increasing the amount of calcium produced, it is possible to promote lead elution and increase the lead concentration in the elution water.

  FIG. 2 is a graph showing the relationship between the calcium ion concentration of the calcium chloride aqueous solution and the lead concentration in the elution water according to this example. The aqueous calcium chloride solution was adjusted so that the calcium ion concentration was 0%, 1%, 5%, 10%, and 20%. The elution water was prepared in accordance with Environmental Agency Notification No. 13. That is, add an aqueous solution adjusted to a predetermined calcium ion concentration to the incinerated ash, 10 times the amount of the incinerated ash, shake for 6 hours continuously, leave still, and filter with a 1.0 μm membrane filter. To prepare elution water.

  As shown in FIG. 2, by using a calcium chloride aqueous solution having a calcium ion concentration of 1% or more, a lead concentration three times or more is detected with respect to an aqueous solution having a calcium ion concentration of 0%. Therefore, it turns out that the elution of lead contained in the incinerated ash can be promoted by using a calcium chloride aqueous solution having a calcium ion concentration of 1% or more.

  FIG. 3 is a graph showing the relationship between the cumulative amount of leachate and the electric conductivity of leachate according to this embodiment. Table 1 summarizes the experimental conditions.

In the experiment, φ104 × 400 mm PVC pipe was filled with 4,000 g of incinerated ash containing water at a height of 300 mm, and water was sprayed from above the incinerated ash using a pump. The watering strength is 160 mm / day. First, incinerated ash is preliminarily hydrated with water that does not contain calcium ions. Thereafter, a calcium chloride aqueous solution adjusted to have a calcium ion concentration of 5% was sprinkled, and then water containing no calcium ions was sprinkled to obtain waste water generated from the bottom of the incinerated ash as leachate.

  As shown in FIG. 3, immediately after the leachate is generated, the electrical conductivity shows a high value. This is because ions such as sodium and potassium contained in the incineration ash are eluted.

  Thereafter, as the cumulative amount of leachate increases, the electrical conductivity decreases, and the cumulative amount of leachate becomes substantially constant in the range of about 300 to 1,400 mL. Since the cumulative leachate amount substantially matches the amount of water previously contained in the incinerated ash, and the electric conductivity of water not containing calcium ions is approximately 0 S / m, the decrease in the electric conductivity is It is thought that the water contained in the incinerated ash flowed while diluting ions such as sodium and potassium contained in the incinerated ash.

  Furthermore, when the cumulative amount of leachate exceeds 1,400 mL, the electrical conductivity increases and then becomes constant at about 16 S / m. Since the electrical conductivity of the sprinkled calcium chloride aqueous solution is about 15 S / m, this leachate is due to the sprinkled calcium chloride aqueous solution switched from the water previously contained in the incinerated ash. It is thought that the electrical conductivity has increased.

  From the above results, the leachate in the range where the cumulative leachate amount is less than about 1,400 mL is due to the water previously contained in the incinerated ash, and the leachate in the range where the cumulative leachate amount is greater than about 1,400 mL It is thought that water originates in the sprinkled calcium chloride aqueous solution. That is, since the order of the leachate coincides with the order of water spraying, and the amount of leachate with increased or decreased electrical conductivity and the amount of water spray almost coincide, It is thought that the water that does not contain the calcium ions that have been sprinkled is flowing as the leachate that extrudes the calcium chloride aqueous solution in the incinerated ash.

  Therefore, by sprinkling the calcium chloride aqueous solution and then watering the calcium ion-free water, the extrusion flow is formed in the incineration ash without mixing the calcium chloride aqueous solution and the water not containing the calcium ion. Therefore, it is not necessary to continue spraying only the calcium chloride aqueous solution on the incinerated ash. Thereby, the liquid quantity of the calcium chloride aqueous solution to sprinkle can be reduced. Furthermore, since the calcium chloride aqueous solution containing the high concentration lead eluted from the incineration ash can be obtained, the efficiency of the leachate treatment can be improved.

  FIG. 4 is a graph showing the relationship between various cleaning methods according to this example, the cumulative lead elution amount, and the cumulative lead elution amount per calcium. Table 2 summarizes various cleaning methods and experimental conditions.

In the experiment, φ580 × 200 mm PVC pipe was filled with 1,580 g of water-containing incinerated ash at a height of 130 mm, and water was sprayed from above the incinerated ash using a pump. The watering strength is 160 mm / day. In the washing method 1, 1,100 mL of water not containing calcium ions was sprinkled on the incineration ash. In the washing method 2, after 170 mL of calcium chloride aqueous solution adjusted to have a calcium ion concentration of 5% was sprayed on the incinerated ash, 930 mL of water not containing calcium ions was sprayed. In the washing method 3, 550 mL of calcium chloride aqueous solution adjusted to have a calcium ion concentration of 5% was sprayed on the incinerated ash, and then 550 mL of water not containing calcium ions was sprayed. In cleaning method 4, 1,100 mL of calcium chloride aqueous solution adjusted to have a calcium ion concentration of 5% was sprayed on the incinerated ash. Watering of calcium chloride aqueous solution and water not containing calcium ions were intermittently performed in multiple times. The liquid-solid ratio was defined as the amount of calcium chloride aqueous solution (mL) divided by the weight (g) of incinerated ash.

  The cumulative lead elution amount in cleaning methods 2, 3 and 4 using an aqueous calcium chloride solution is larger than the cumulative lead elution amount in cleaning method 1 using only water not containing calcium ions. Therefore, elution of lead contained in incineration ash is promoted by cleaning methods 2, 3 and 4 using an aqueous calcium chloride solution, and lead can be removed more efficiently than cleaning method 1 using only water not containing calcium ions. I understand.

  Moreover, since the contact time between the incinerated ash and the aqueous calcium chloride solution becomes longer as the amount of water sprayed from the aqueous calcium chloride solution increases, the cumulative lead elution amount increases. Therefore, in addition to the watering time of the calcium chloride aqueous solution, it is important to ensure the contact time between the incinerated ash and the calcium chloride aqueous solution by, for example, standing and curing after watering. Since the contact time increases in proportion to the watering time of the aqueous calcium chloride solution, it is desirable that the contact time is at least 3 hours, preferably 3 hours or more including the watering time.

  On the other hand, when the cumulative lead elution amount per calcium is compared, the values of cleaning methods 2 and 3 in which the calcium chloride aqueous solution is sprinkled and then water containing no calcium ions is sprinkled. The cleaning method 4 in which only the calcium chloride aqueous solution is sprinkled. Higher than the value of. As a result, when the liquid-solid ratio is less than 1.0, it is possible to efficiently elute lead with a small amount of calcium chloride by watering calcium calcium aqueous solution and then spraying water not containing calcium ions. It turns out that it is.

  Therefore, when the purpose of cleaning is to reduce the lead content, the amount of water sprayed from the calcium compound aqueous solution is increased to increase the lead elution amount, or the calcium ion concentration in the calcium compound aqueous solution to be sprinkled is increased. Just do it. On the other hand, when the purpose of washing is to suppress the elution amount of lead, after watering the calcium compound aqueous solution, water that does not contain calcium ions may be sprinkled, and a method of continuously watering the calcium compound aqueous solution (for example, the above) The amount of calcium compound aqueous solution required is less than that required for cleaning method 4), and lead can be removed efficiently. That is, in this method, the amount of calcium compound is controlled in accordance with the purpose and target of cleaning, and the incineration ash can be efficiently cleaned using the minimum amount of calcium compound.

  FIG. 5 is a graph showing the relationship between various cleaning methods according to this example and the lead concentration in the elution water. The lead concentration in the elution water shown in the figure represents the risk of elution of lead from the incinerated ash. The elution water of each incineration ash before and after cleaning was prepared in accordance with Notification No. 13 of the Environment Agency. That is, 10 times the amount of pure water was added to the incinerated ash, shaken continuously for 6 hours, and then allowed to stand, and further filtered through a 1.0 μm membrane filter to prepare elution water. . Cleaning methods 1, 2, 3 and 4 are the same as the various cleaning methods shown in Table 2.

  As shown in FIG. 5, the concentration of lead in the elution water after washing with watering (cleaning methods 1, 2, 3 and 4) is greatly reduced from the concentration of lead eluted from the incinerated ash before washing. Further, in the cleaning methods 2 and 3 in which the calcium compound aqueous solution is sprinkled and then water containing no calcium ions is sprinkled, since the lead concentration in the elution water is lower than the other cleaning methods 1 and 4, the calcium compound aqueous solution is sprinkled. After that, the risk of elution of lead from the incinerated ash can be greatly reduced by using a method of sprinkling water that does not contain calcium ions.

  FIG. 6 is a graph showing the relationship between the type of gas to be ventilated and the lead concentration in the elution water. In the experiment, φ580 × 200 mm PVC pipe was filled with 1,580 g of water-containing incinerated ash at a height of 130 mm, sprinkled with a pump from the top of the incinerated ash, and further vented from the bottom of the incinerated ash. The water spray strength is 190 mm / day, and the ventilation rate is 2 mm / second. Elution water was prepared for each incinerated ash after washing. The elution water was prepared in accordance with Environmental Agency Notification No. 13. That is, 10 times the amount of pure water was added to the incinerated ash, shaken continuously for 6 hours, and then allowed to stand, and further filtered through a 1.0 μm membrane filter to prepare elution water. .

In the system in which air (atmosphere) and carbon dioxide (CO ₂ ) are ventilated, the lead concentration in the elution water is greatly reduced as compared with the case in which aeration is not performed, and further, the system in which 10% and 100% of carbon dioxide are aerated. The lead concentration in the elution water decreased compared to the system in which air (atmosphere) was ventilated. Moreover, in the system in which carbon dioxide was aerated, the carbon dioxide concentrations were 10% and 100% different from each other by 10 times, but the lead concentrations in the elution water were both below the detection limit, and no difference was observed.

  Therefore, in addition to washing the incinerated ash by watering, it is understood that lead can be carbonated by reducing the risk of elution from the incinerated ash by aeration during or after watering. Ventilation can enhance the elution suppression effect by using air (atmosphere) or gas having a larger amount of carbon dioxide than the atmosphere such as exhaust gas from an incinerator.

  As described above, in this embodiment, the calcium compound aqueous solution is first sprinkled from the incinerated ash to be washed, and then water not containing calcium ions is sprinkled. As a method of watering, mist-like watering by a sprinkler or the like, or dripping from a tube, a hose or a pipe is performed. Sprinkling is performed intermittently, and a small amount of watering is performed a small number of times, so that a small amount of water can be efficiently brought into contact with the incineration ash, and the formation of a water channel can be suppressed. .

  As a method of using the calcium compound, a calcium compound aqueous solution having a liquid-solid ratio of less than 1.0 is supplied to the incineration ash. The calcium ion concentration of the calcium compound aqueous solution is 1% or more, and the contact time between the calcium aqueous solution and the incineration ash is 3 hours or more. The lead contained in the incineration ash can be reduced by efficiently eluting more lead from the incineration ash into the calcium compound aqueous solution by the lead elution promoting effect of the calcium compound.

  In addition, after sprinkling the calcium compound aqueous solution, water containing no calcium ions is sprinkled, and the calcium compound aqueous solution containing a large amount of lead is washed away to remove lead eluted from the incineration ash, and lead from the incineration ash after washing Elution can be reduced.

  Furthermore, reduction of lead elution can be promoted by ventilating a gas having a larger amount of carbon dioxide than air, such as air or exhaust gas, during or after watering.

  As described above, in this example, when the supply amount of the calcium compound aqueous solution that promotes the elution of lead is less than 1.0 in the liquid-solid ratio, the lead in the incineration ash is reduced and the lead from the incineration ash after cleaning is reduced. Elution can be suppressed. Further, since the amount of waste water generated after washing is the same amount as the supply amount, it is possible to reduce the cost of chemicals and the amount of water required for waste water treatment. Thereby, a low-cost and efficient method for cleaning incineration ash can be provided.

<Specific example>
Next, a specific method for cleaning incineration ash according to the present embodiment will be described.

  FIG. 7 is a schematic view of a cleaning apparatus used for cleaning incineration ash according to the present embodiment.

As shown in FIG. 7, for example, a container CO having a capacity of 4 t (8 m ³ ) is used as a cleaning tank for the incineration ash 1. 3t of incineration ash 1 discharged from the incineration facility is uniformly spread over the container CO at a thickness of about 30 cm to 50 cm. The container CO is installed under a hopper that carries out the incineration ash 1 of the incineration facility, receives the incineration ash 1 directly, and then transfers the incineration ash 1 to a cleaning facility that performs sprinkling cleaning and performs a cleaning process.

  A device such as a sprinkler capable of spraying liquid or a tube, hose or pipe capable of dripping liquid is installed at one or a plurality of locations in the cleaning facility so that the water spray is distributed uniformly throughout the container CO. Using this apparatus, an aqueous calcium chloride solution 2 in which 125 kg of calcium chloride is dissolved in advance is sprayed from the upper part of the container CO to the incinerated ash 1 in a stationary state. The amount of water sprayed from the aqueous calcium chloride solution 2 is, for example, 900 L at a liquid / solid ratio of 0.3. Thereafter, water 3 not containing calcium ions is sprayed on the incineration ash 1 in a stationary state, and the calcium chloride aqueous solution 2 is washed out from the incineration ash 1. The amount of water 3 that does not contain calcium ions is, for example, 1,700 L. Watering is performed intermittently in a plurality of times, and the watering strength is 160 mm / day and 24 hours. Moreover, the incineration ash 1 is ventilated at an aeration rate of 0.01 to 5 mm / sec during or after each watering. The aeration rate is changed according to the amount of gaseous carbon dioxide and the aeration time, and the aeration rate may be slower as the amount is larger and the time is longer.

  The leachate 4 which becomes waste water is collected at the lower part of the container CO and is appropriately treated in the leachate treatment facility or treated by blowing it into an incinerator.

<Modification 1>
It is possible to circulate and use the obtained leachate in the calcium compound aqueous solution that sprays water to promote the elution of lead contained in the incinerated ash. Since the leachate contains calcium ions derived from calcium compounds and incinerated ash at high concentrations, the leachate can be used as an aqueous calcium compound solution that promotes lead elution.

  FIG. 8 is a schematic view of a cleaning apparatus used for cleaning incinerated ash according to Modification 1 of the present embodiment.

As shown in FIG. 8, for example, a container CO having a capacity of 4 t (8 m ³ ) is used as a cleaning tank for the incineration ash 1. 3t of incineration ash 1 discharged from the incineration facility is uniformly spread over the container CO at a thickness of about 30 cm to 50 cm. The container CO is installed under a hopper that carries out the incineration ash 1 of the incineration facility, receives the incineration ash 1 directly, and then transfers the incineration ash 1 to a cleaning facility that performs sprinkling cleaning and performs a cleaning process.

  A device such as a sprinkler capable of spraying liquid or a tube, hose or pipe capable of dripping liquid is installed at one or a plurality of locations in the cleaning facility so that the water spray is distributed uniformly throughout the container CO. Using this apparatus, an aqueous calcium chloride solution 2 in which 125 kg of calcium chloride is dissolved in advance is sprayed from the upper part of the container CO to the incinerated ash 1 in a stationary state. The amount of water sprayed from the aqueous calcium chloride solution 2 is, for example, 900 L at a liquid / solid ratio of 0.3. Thereafter, water 3 not containing calcium ions is sprayed on the incineration ash 1 in a stationary state, and the calcium chloride aqueous solution 2 is washed out from the incineration ash 1. The amount of water 3 that does not contain calcium ions is, for example, 1,700 L. Watering is performed intermittently in a plurality of times, and the watering strength during circulation is 700 mm / day and 18 hours, and the watering strength during washing is 160 mm / day and 6 hours for a total of 24 hours. Moreover, the incinerated ash 1 is ventilated at a ventilation rate of 0.01 to 5 mm / sec during or after watering. The aeration rate is changed according to the amount of gaseous carbon dioxide and the aeration time, and the aeration rate may be slower as the amount is larger and the time is longer.

  During the circulation, the leachate 4 is transferred from a tank for collecting the leachate 4 by a pump and sprinkled from the upper part of the container CO. By removing lead from the water in the tank that collects the leachate 4, re-adsorption of lead to the incinerated ash 1 by circulation can be prevented. Lead removal methods include aeration using air or carbon dioxide, ion exchange using ion exchange resin, adsorption using an adsorbent capable of adsorbing lead such as zeolite, coprecipitation using iron salt, sodium sulfide It is possible to remove by a substitution method or the like when a slightly soluble sulfur compound is produced using a method, a ferrite method, an iron powder method, a treatment method in which phosphoric acid is added to produce apatite, or a chelate is present in water. The removal treatment by the aeration method removes calcium ions, but in the leachate 4, the calcium ion concentration is much higher than the lead ion concentration. It is thought that this does not affect the promotion of lead elution.

  The leachate 4 which becomes waste water is collected at the lower part of the container CO and is appropriately treated in the leachate treatment facility or treated by blowing it into an incinerator.

<Modification 2>
In the specific example and the modified example 1, the calcium compound aqueous solution and the water not containing calcium ions are supplied to the incineration ash by watering, respectively, but the calcium compound may be supplied to the incineration ash by a method other than liquid. That is, even if the calcium compound aqueous solution is not used, the calcium compound aqueous solution is prepared in the incinerated ash by first supplying the calcium compound to the incinerated ash and sprinkling water not containing calcium ions. If the lead is eluted, and then water containing no calcium ions is supplied to the incineration ash to wash away the calcium compound aqueous solution containing a large amount of lead, the same effects as those of the specific example and the modified example 1 can be obtained. In Modifications 2, 3, and 4, a method that does not depend on watering will be described.

  FIG. 9 is a schematic view of a cleaning apparatus used for cleaning incinerated ash according to Modification 2 of the present embodiment.

As shown in FIG. 9, for example, a container CO having a capacity of 4 t (8 m ³ ) is used as a cleaning tank for the incineration ash 1. 3t of incineration ash 1 discharged from the incineration facility is uniformly spread over the container CO at a thickness of about 30 cm to 50 cm. Further, solid calcium chloride 5 is uniformly spread on the incineration ash 1. The amount of calcium chloride 5 is, for example, 125 kg. When a sheet of calcium chloride 5 is used, a predetermined amount is evenly spread on the incineration ash 1 so that the amount of calcium chloride 5 contained is, for example, 125 kg. The sheet of calcium chloride 5 is one in which calcium chloride 5 is sandwiched or knitted with a nonwoven fabric, a net, cotton or a film, etc., or a sheet having a bag-like structure that is permeable to water and calcium chloride 5 is inserted. Conceivable. The container CO is installed under a hopper that carries out the incineration ash 1 of the incineration facility, receives the incineration ash 1 directly, and then transfers the incineration ash 1 to a cleaning facility that performs sprinkling cleaning and performs a cleaning process.

  A device such as a sprinkler capable of spraying liquid or a tube, hose or pipe capable of dripping liquid is installed at one or a plurality of locations in the cleaning facility so that the water spray is distributed uniformly throughout the container CO. For watering by dripping, when scouring with water occurs and it is assumed that the watering does not spread uniformly over the calcium compound, a sheet of non-woven fabric or the like is laid over the sprinkled calcium chloride 5 and from the top Sprinkle water. Using this apparatus, water 3 not containing calcium ions is sprinkled from the upper part of the container CO to the incinerated ash 1 in a stationary state. At this time, as a part for preparing a calcium chloride aqueous solution that promotes lead elution, for example, 900 L of water 3 not containing calcium ions is sprinkled, and as a part used for washing out the calcium chloride aqueous solution, for example, 1,700 L of calcium ions are used. Water 3 not included is sprinkled. Watering is performed intermittently in a plurality of times, and the watering strength is 160 mm / day and 24 hours. Moreover, the incinerated ash 1 is ventilated at a ventilation rate of 0.01 to 5 mm / sec during or after watering. The aeration rate is changed according to the amount of gaseous carbon dioxide and the aeration time, and the aeration rate may be slower as the amount is larger and the time is longer.

  The amount of calcium chloride 5 added during the watering period is set so that the calcium ion concentration during water passage does not become less than 1%. In the case of the modification 2, even if water 3 not containing 900 L of calcium ions is sprayed at once with respect to 125 kg of calcium chloride 5, the calcium ion concentration is (125 kg × 1,000 × (40/111)) / 900 L = 50.1 g / L, not less than 1% (10 g / L).

  It is assumed that the lead elution promotion was terminated by 900 L of water sprinkling, and 1,700 L of water 3 not containing calcium ions used to wash out the calcium chloride aqueous solution containing lead whose elution was promoted was continuously sprinkled. . Thereby, dissolution of calcium chloride 5 in the solid or the sheet proceeds, and the calcium ion concentration in the passing water becomes less than 1%.

  The leachate 4 which becomes waste water is collected at the lower part of the container CO and is appropriately treated in the leachate treatment facility or treated by blowing it into an incinerator.

<Modification 3>
FIG. 10 is a schematic view of a cleaning apparatus used for cleaning incinerated ash according to Modification 3 of the present embodiment.

As shown in FIG. 10, for example, a container CO having a capacity of 4 t (8 m ³ ) is used as a cleaning tank for the incineration ash 1. The incineration ash 1 discharged from the incineration facility is uniformly spread over the container CO at a thickness of about 10 cm to 20 cm, and the solid calcium chloride 5 is evenly spread over the thickness of about 10 cm to 20 cm. . Thereafter, in the same manner, the incineration ash 1 and the solid calcium chloride 5 are alternately stacked on the entire container CO until the incineration ash 1 becomes 3 t. The uppermost layer is coated with solid calcium chloride 5. The total amount of the solid calcium chloride 5 is, for example, 125 kg, and is divided into each layer and sprinkled. When a calcium chloride 5 sheet is used, a predetermined amount is divided into each layer so that the amount of calcium chloride 5 contained is, for example, 125 kg, and spread uniformly. The sheet of calcium chloride 5 is one in which calcium chloride 5 is sandwiched or knitted with a nonwoven fabric, a net, cotton or a film, etc., or a sheet having a bag-like structure that is permeable to water and calcium chloride 5 is inserted. Conceivable.

  The container CO is installed under the hopper that carries out the incineration ash 1 of the incineration facility, and receives the incineration ash 1 directly, and each time one layer is received, the calcium chloride 5 is sprinkled on it, or the calcium chloride 5 Spread the sheet. Thereafter, the incinerated ash 1 is transferred to a cleaning facility for performing sprinkling cleaning, and cleaning processing is performed.

  A device such as a sprinkler capable of spraying liquid or a tube, hose or pipe capable of dripping liquid is installed at one or a plurality of locations in the cleaning facility so that the water spray is distributed uniformly throughout the container CO. For sprinkling by dripping at the top, if scouring with water occurs and it is assumed that the sprinkling does not spread uniformly over the calcium compound, spread a sheet such as a non-woven fabric over the sprinkled calcium chloride 5, Watering from the top. Using this apparatus, water 3 not containing calcium ions is sprinkled from the upper part of the container CO to the incinerated ash 1 in a stationary state. At this time, as a part for preparing a calcium chloride aqueous solution that promotes lead elution, for example, 900 L of water 3 not containing calcium ions is sprinkled, and as a part used for washing out the calcium chloride aqueous solution, for example, 1,700 L of calcium ions are used. Water 3 not included is sprinkled. Watering is performed intermittently in a plurality of times, and the watering strength is 160 mm / day and 24 hours. Moreover, the incinerated ash 1 is ventilated at a ventilation rate of 0.01 to 5 mm / sec during or after watering. The aeration rate is changed according to the amount of gaseous carbon dioxide and the aeration time, and the aeration rate may be slower as the amount is larger and the time is longer.

  The amount of calcium chloride 5 added during the watering period is set so that the calcium ion concentration during water passage does not become less than 1%. In the case of the modification 3, even if water 3 not containing 900 L of calcium ions is sprayed at once with respect to 125 kg of calcium chloride 5, the calcium ion concentration is (125 kg × 1,000 × (40/111)) / 900 L = 50.1 g / L, not less than 1% (10 g / L).

  It is assumed that the lead elution promotion was terminated by 900 L of water sprinkling, and 1,700 L of water 3 not containing calcium ions used to wash out the calcium chloride aqueous solution containing lead whose elution was promoted was continuously sprinkled. . Thereby, dissolution of calcium chloride 5 in the solid or the sheet proceeds, and the calcium ion concentration in the passing water becomes less than 1%.

  The leachate 4 which becomes waste water is collected at the lower part of the container CO and is appropriately treated in the leachate treatment facility or treated by blowing it into an incinerator.

<Modification 4>
FIG. 11 is a schematic view of a cleaning apparatus used for cleaning incineration ash according to Modification 4 of the present embodiment.

As shown in FIG. 11, for example, a container CO having a capacity of 4 t (8 m ³ ) is used as a cleaning tank for the incineration ash 1. 3t of incineration ash 1 discharged from the incineration facility is poured into this container CO, solid calcium chloride 5 is added, and the mixture is stirred with a backhoe or the like. The amount of calcium chloride 5 is, for example, 125 kg. The kneaded incineration ash 1 is spread uniformly with a thickness of about 30 to 50 cm. The container CO is installed under a hopper that carries out the incineration ash 1 of the incineration facility, receives the incineration ash 1 directly, and then transfers the incineration ash 1 to a cleaning facility that performs sprinkling cleaning and performs a cleaning process.

  A device such as a sprinkler capable of spraying liquid or a tube, hose or pipe capable of dripping liquid is installed at one or a plurality of locations in the cleaning facility so that the water spray is distributed uniformly throughout the container CO. Using this apparatus, water 3 not containing calcium ions is sprinkled from the upper part of the container CO to the incinerated ash 1 in a stationary state. At this time, as a part for preparing a calcium chloride aqueous solution that promotes lead elution, for example, 900 L of water 3 not containing calcium ions is sprinkled, and as a part used for washing out the calcium chloride aqueous solution, for example, 1,700 L of calcium ions are used. Water 3 not included is sprinkled. Watering is performed intermittently in a plurality of times, and the watering strength is 160 mm / day and 24 hours. Moreover, the incinerated ash 1 is ventilated at a ventilation rate of 0.01 to 5 mm / sec during or after watering. The aeration rate is changed according to the amount of gaseous carbon dioxide and the aeration time, and the aeration rate may be slower as the amount is larger and the time is longer.

  The amount of calcium chloride 5 added during the watering period is set so that the calcium ion concentration during water passage does not become less than 1%. In the case of the modification 4, even if water 3 not containing 900 L of calcium ions is sprayed at once with respect to 125 kg of calcium chloride 5, the calcium ion concentration is (125 kg × 1,000 × (40/111)) / 900 L = 50.1 g / L, not less than 1% (10 g / L).

  It is assumed that the lead elution promotion was terminated by 900 L of water sprinkling, and 1,700 L of water 3 that does not contain calcium ions used to wash out the calcium chloride aqueous solution containing lead whose elution was promoted should be continuously sprinkled. Then, the dissolution of the solid calcium chloride 5 proceeds, and the calcium ion concentration in the passing water becomes less than 1%.

  The leachate 4 which becomes waste water is collected at the lower part of the container CO and is appropriately treated in the leachate treatment facility or treated by blowing it into an incinerator.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, the washing tank filled with incineration ash may have a structure as a tank. For example, a tank made of steel, FRP (Fiber Reinforced Plastics), or concrete may be used in addition to the container. The thickness of the incinerated ash, the thickness of the fixed or calcium compound sheet, and the number of layers of the incinerated ash or calcium compound depend on the size of the washing tank and the unit volume weight of the incinerated ash. In addition, the amount of calcium compound can be increased or decreased depending on the use of a calcium compound other than calcium chloride and the amount of lead contained in the incinerated ash.

1 Incinerated ash 2 Calcium chloride aqueous solution 3 Water not containing calcium ions 4 Leached water (waste water)
5 Calcium chloride CO container

Claims (5)

(A) including a step of supplying a calcium compound aqueous solution to the left incinerated ash;
The calcium ion concentration of the calcium compound aqueous solution is 1% or more,
The liquid-solid ratio obtained by dividing the amount of the calcium compound aqueous solution by the weight of the incinerated ash is less than 1.0,
The contact time between the incinerated ash and the calcium compound aqueous solution is 3 hours or more,
When supplying the calcium compound aqueous solution to the incinerated ash or after supplying the incinerated ash, ventilate the incinerated ash,
The step (a)
(A1) depositing a calcium compound on the incineration ash,
(A2) supplying water not containing calcium ions to the calcium compound and the incinerated ash from the calcium compound side;
Incineration ash cleaning method including (A) including a step of supplying a calcium compound aqueous solution to the left incinerated ash;
The calcium ion concentration of the calcium compound aqueous solution is 1% or more,
The liquid-solid ratio obtained by dividing the amount of the calcium compound aqueous solution by the weight of the incinerated ash is less than 1.0,
The contact time between the incinerated ash and the calcium compound aqueous solution is 3 hours or more,
When supplying the calcium compound aqueous solution to the incinerated ash or after supplying the incinerated ash, ventilate the incinerated ash,
The step (a)
(A1) a step of alternately stacking the incinerated ash and the calcium compound a plurality of times to form a laminate having the uppermost layer as the calcium compound;
(A2) supplying water containing no calcium ions from the calcium compound side of the uppermost layer to the stack;
Incineration ash cleaning method including (A) including a step of supplying a calcium compound aqueous solution to the left incinerated ash;
The calcium ion concentration of the calcium compound aqueous solution is 1% or more,
The liquid-solid ratio obtained by dividing the amount of the calcium compound aqueous solution by the weight of the incinerated ash is less than 1.0,
The contact time between the incinerated ash and the calcium compound aqueous solution is 3 hours or more,
When supplying the calcium compound aqueous solution to the incinerated ash or after supplying the incinerated ash, ventilate the incinerated ash,
The step (a)
(A1) a step of kneading the incinerated ash and the calcium compound,
(A2) supplying water not containing calcium ions to the calcium compound and the incinerated ash;
Incineration ash cleaning method including In the cleaning method of incineration ash according to any one of claims 1 to 3 ,
The method for cleaning incineration ash, wherein the water not containing calcium ions is supplied intermittently. In the incineration ash cleaning method according to claim 4 ,
A method for cleaning incineration ash, wherein the water not containing calcium ions is sprayed or dripped.

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