JP7041278B2 - Chlorine-containing powder washing method and chlorine-containing powder washing system - Google Patents

Description

The present invention relates to a method for washing chlorine-containing powder with water and a system for washing chlorine-containing powder, which can be suitably applied to the use of incinerated ash as a raw material for cement.

In the recycling process of waste by converting it into a raw material for cement, chlorine-containing waste may cause problems such as blockage of cement manufacturing equipment due to the chlorine. Therefore, when chlorine-containing powder such as incinerator ash or cement kiln dust (CKD) is used as a raw material for cement as waste to be treated, the chlorine content should be reduced by desalting before use. Is being done.

Regarding the desalting treatment of incinerator ash and the like, for example, Patent Document 1 discloses a method of adding water to incinerator ash to elute chlorine and then dehydrating it. Further, Patent Document 2 discloses a method of washing and desalting incinerator ash a plurality of times by repeating mixing with water and dehydration. Further, Patent Document 3 discloses a method of introducing carbon dioxide into a washing suspension of ash dust to promote elution of chloride ions from the sparingly soluble Friedel salt contained in the ash dust.

Japanese Unexamined Patent Publication No. 2002-338312 Japanese Unexamined Patent Application Publication No. 2003-21129 Japanese Unexamined Patent Publication No. 10-128304

Normally, when chlorine-containing powder such as incineration ash is continuously washed with water, the chlorine-containing powder made into a slurry by adding at least water is stored in a treatment tank having a predetermined capacity, and the mixture is stirred by a stirring blade. At the same time, a method such as washing with water while blowing a gas containing carbon dioxide, which works favorably for the elution of chlorine ions, into bubbles with a disk-type diffuser (diffuser) or the like, and separating the overflowed slurry from the treatment tank by filtration. Is adopted. However, according to the findings of the present inventors, the slurry that has been stirred by such a method has a problem that it takes a relatively long time to separate by filtration with a filter press or the like.

Therefore, an object of the present invention is to shorten the time required for filtering and separating a slurry made by adding at least water to a chlorine-containing powder such as incineration ash, thereby enabling more efficient treatment. It is an object of the present invention to provide a water washing treatment method for powders and a water washing treatment system for chlorine-containing powders.

In order to achieve the above object, the present invention firstly:
A chlorine-containing powder introduction step in which a slurry formed by adding at least water to a chlorine-containing powder is stored in a treatment tank having a predetermined capacity.
A chlorine elution step of stirring the slurry contained in the treatment tank to elute the chlorine contained in the chlorine-containing powder into the liquid phase.
A filter separation step for obtaining a desalted cake by filtering a part or all of the liquid phase from the slurry after chlorine elution is provided.
In the stirring of the slurry in the chlorine elution step, a gas containing carbon dioxide is blown into the slurry contained in the treatment tank, and the gas recirculates while entraining the slurry over the lower and upper layers of the contained slurry. The present invention provides a method for washing chlorine-containing powder with water by forming a mixed stirring flow of the gas and the slurry.

According to the water washing treatment method for the chlorine-containing powder, stirring in the chlorine elution step of the slurry formed by adding at least water to the chlorine-containing powder is performed by blowing a gas containing carbon dioxide into the slurry contained in the treatment tank. This is performed by forming a mixed stirring flow of the gas and the slurry in which the gas recirculates while entraining the slurry over the lower and upper layers of the slurry contained in the treatment tank, so that the solid-state particles having a relatively large particle size are used. Even if there is, it does not stay on the bottom side in the treatment tank and can be well dispersed in the entire slurry. As a result, a state in which the particle size distribution of the solid phase particles of the solid phase contained in the slurry is wide and well dispersed is formed, and the particle size is relatively large in the filter separation step after the chlorine elution step. Large solid-phase particles become nuclei, and solid-phase particles with a relatively small particle size are also combined to form a packed structure with appropriately communicated interparticle voids, making it easier for the liquid phase to pass through. Then, the time required for separating the slurry that has undergone the chlorine elution step by filtration can be shortened.

In order to achieve the above object, secondly, in the method for washing the chlorine-containing powder with water, the treatment tank contains chlorine into which the slurry contained in the treatment tank is additionally introduced. The present invention provides the water washing treatment method, which is configured to overflow according to the powder and be carried out for the filtration separation step.

According to the above configuration, since the slurry is carried out from the processing tank after the chlorine elution step, no special work by an operator or the like is required, and the slurry is continuously introduced according to the chlorine-containing powder to be additionally introduced. Can be washed with water.

In order to achieve the above object, the present invention thirdly provides the water washing treatment method in which the liquid phase is separated by a filter press in the filter separation separation step in the water washing treatment method of the chlorine-containing powder. It is a thing.

According to the above configuration, the desalted cake can be obtained more efficiently in the filtration separation step.

In order to achieve the above object, fourthly, in the method for washing the chlorine-containing powder with water, the chlorine-containing powder was selected from incineration fly ash, molten fly ash, and cement kiln dust. It is intended to provide the water washing treatment method including seeds or two or more kinds.

According to the above configuration, incinerator fly ash, molten fly ash, cement kiln dust and the like, which are wastes containing chlorine, can be desalted and effectively used as a raw material for cement, for example.

In order to achieve the above object, the present invention fifthly enables the water washing treatment according to the chlorine-containing powder continuously introduced in the water washing treatment method for the chlorine-containing powder. It provides a washing treatment method.

In order to achieve the above object, the present invention is described in the sixth aspect.
A treatment tank having a predetermined capacity for accommodating a slurry made by adding at least water to a chlorine-containing powder, and a treatment tank.
A gas containing carbon dioxide is blown into the slurry provided in the treatment tank and contained in the treatment tank, and the gas recirculates while entraining the slurry over the lower and upper layers of the contained slurry. A tubular air diffuser for forming a mixed stirring flow with the slurry, and
Provided is a water washing treatment system for chlorine-containing powder provided with a filter separation device for filtering a part or all of the liquid phase from the slurry taken out from the treatment tank to obtain a desalted cake.

According to the water washing treatment system for the chlorine-containing powder, the stirring in the chlorine elution step of stirring the slurry made by adding at least water to the chlorine-containing powder to elute chlorine into the liquid phase is attached to the treatment tank. A gas containing carbon dioxide is blown into the slurry contained in the treatment tank by using the cylindrical air diffuser, and the gas recirculates while entraining the slurry over the lower and upper layers of the slurry contained in the treatment tank. Since it is possible to form a mixed stirring flow of the gas and the slurry, even solid-phase particles having a relatively large particle size stay on the bottom side in the treatment tank when the slurry is stirred. It can be well dispersed in the entire slurry without any problem. As a result, a state in which the particle size distribution of the solid phase particles of the solid phase contained in the slurry is wide and well dispersed is formed, and the particle size is relatively large in the filter separation step after the chlorine elution step. Large solid-phase particles become nuclei, and solid-phase particles with a relatively small particle size are also combined to form a packed structure with appropriately communicated interparticle voids, making it easier for the liquid phase to pass through. Then, the time required for separating the slurry that has undergone the chlorine elution step by filtration can be shortened.

In order to achieve the above object, seventhly, in the chlorine-containing powder washing treatment system, the treatment tank contains chlorine into which the slurry contained in the treatment tank is additionally introduced. It provides the water washing treatment system which is configured to overflow according to the powder and be carried out to the filter separation device.

According to the above configuration, since the slurry is carried out from the processing tank after the chlorine elution step, no special work by an operator or the like is required, and the slurry is continuously introduced according to the chlorine-containing powder to be additionally introduced. Can be washed with water.

In order to achieve the above object, the present invention provides, eighthly, in the water washing treatment system for chlorine-containing powder, the water washing treatment system in which the filter separation device is a filter press.

According to the above configuration, the desalted cake can be obtained more efficiently in the filter separation step by the filter separation device.

In order to achieve the above object, a ninth aspect of the present invention is the water washing treatment system for chlorine-containing powder, further comprising a transport device for transporting the obtained desalted cake to a cement manufacturing facility. It provides a processing system.

According to the above configuration, the desalted cake obtained by desalting the waste containing chlorine, for example, incinerator fly ash, molten fly ash, cement kiln dust, etc., is directly transported to the cement manufacturing facility. It can be effectively used as a raw material for cement.

In order to achieve the above object, the tenth aspect of the present invention is to enable the water washing treatment according to the chlorine-containing powder continuously introduced in the water washing treatment system for the chlorine-containing powder. It provides a washing treatment system.

According to the present invention, a chlorine-containing powder that shortens the time required for filtering and separating a slurry made by adding at least water to a chlorine-containing powder such as incineration ash, and enables more efficient treatment. A method for washing with water and a system for washing chlorine-containing powder can be provided. Therefore, waste such as incinerator ash can be efficiently desalted and effectively used as a raw material for cement.

It is a flow figure explaining the basic structure of the water washing treatment performed in this invention. It is a schematic block diagram of an example of the water washing treatment system of the chlorine-containing powder which concerns on this invention. It is a graph which shows the result of having investigated the particle size distribution of the solid phase component of the desalting cake C1 obtained in Example 1 and Comparative Examples 1 and 2 in Test Example 2.

The treatment target of the present invention may be any powder containing chlorine, and is not particularly limited, and examples thereof include incinerated fly ash, molten fly ash, and cement kiln dust. These are wastes that have been effectively used as a raw material for cement after desalination, and are typical fly ash for municipal waste incineration, that is, fly ash generated when incineration of household waste (book). In the specification, it is simply referred to as "incineration fly ash"), which generally contains chlorine (Cl) at a concentration of about 10% by mass to 30% by mass, and is generated from a gasification and melting furnace. The fly ash (referred to simply as “molten fly ash” in the present specification) generally contains chlorine at a concentration of about 10% by mass to 40% by mass. On the other hand, the cement kiln dust, which is dust contained in the cement kiln bleed air gas, generally contains chlorine at a concentration of about 10% by mass to 40% by mass.

According to the present invention, the chlorine content of the waste as described above is, for example, typically a concentration of about 0.1% by mass to 3% by mass, and more typically 0.1% by mass to 1.5. The concentration can be reduced to about mass%. The desalted cake having such a reduced chlorine content can be effectively used as a raw material for cement and the like.

The concentration of chlorine in the chlorine-containing powder can be measured by a well-known method, for example, ISO 29581-2 Cement-Test methods-Part2: Chemical analysis by X-ray fluorescence, or the Cement Association standard test method JCAS I-. 05 A fluorescent X-ray analysis method or the like to which "a method for quantifying chlorine in cement by fluorescent X-ray analysis" or the like is applied mutatis mutandis is preferably exemplified.

Hereinafter, the drawings will be referred to in order to explain the present invention more specifically, but the present invention is not limited to the embodiments described together with these drawings.

FIG. 1 shows a flow chart illustrating a basic configuration of a water washing treatment performed in the present invention. As shown in this flow chart, the water washing treatment method according to the present invention is a chlorine-containing powder introduction step (s-) in which a slurry formed by adding at least water to a chlorine-containing powder is stored in a treatment tank having a predetermined capacity. 1) and the chlorine elution step (s-2) in which the chlorine contained in the chlorine-containing powder is eluted into the liquid phase by stirring the slurry contained in the treatment tank, and one of the liquid phases from the slurry after chlorine elution. It is provided with a filtration separation step (s-3) for obtaining a desalted cake by filtering a part or all of the material.

Then, in the water washing treatment method according to the present invention, the slurry in the chlorine elution step is agitated by blowing a gas containing carbon dioxide into the slurry contained in the treatment tank, and the lower layer of the slurry contained in the treatment tank and the slurry. This is performed by forming a mixed stirring flow of the slurry and the gas in which the gas recirculates while entraining the slurry over the upper layer. As a result, even solid phase particles having a relatively large particle size do not stay on the bottom side in the treatment tank and can be well dispersed in the entire slurry. In addition, the particle size distribution of the solid phase particles contained in the slurry is wide and well dispersed, and the particle size is relatively large in the filtration separation step after the chlorine elution step. The solid-phase particles become nuclei, and together with the solid-phase particles having a relatively small particle size, a packed structure having appropriately communicated interparticle voids is formed, and a good filtration rate is exhibited. Due to this excellent filtration rate, the time required for the separation step by filtration is remarkably shortened, and the chlorine-containing powder can be efficiently washed with water.

Further, in the water washing treatment method according to the present invention, the water washing treatment can be performed according to the chlorine-containing powder continuously introduced. That is, in general, the introduction of the chlorine-containing powder can continuously supply, for example, a desalting washing liquid containing chlorine-containing powder and at least water to the treatment tank, but the subsequent separation by filtration is possible. In the process, depending on the specifications of the filter separation device to be used, batch-type processing is generally usual, but by providing a buffer tank for the slurry supplied from the chlorine elution step on the upstream side of the filter separation device, etc. It is possible to carry out the washing treatment without disturbing the continuity of introduction of the chlorine-containing powder. In addition, "continuity" here does not necessarily mean that the washed product is continuously produced without any interruption on the time axis, and when viewed within a time range that is common sense in operation, Typically, for example, when viewed in a time range of about 50 minutes to 100 minutes, it means that the production of the washed product is not interrupted due to the continuity of introduction of the chlorine-containing powder. As a result, the operational efficiency of the washing process can be sufficiently improved.

FIG. 2 shows a schematic configuration explanatory diagram of an example of a water washing treatment system for chlorine-containing powder according to the present invention.

As shown in FIG. 2, the water washing treatment system 1 for the chlorine-containing powder according to this embodiment is provided with a treatment tank 2, and the treatment tank 2 contains chlorine supplied from the chlorine-containing powder supply device 21. The powder P1 and the first desalting washing liquid W1 supplied from the first desalting washing liquid supply device 22 are introduced, and the pH adjusting agent pH1 supplied from the pH adjusting agent supplying device 23 is also introduced as needed. It is said that it can be introduced. In the embodiment shown in FIG. 2, the slurry materials P1, W1 and pH1 are continuously supplied to the treatment tank 2 from the supply devices 21 to 23, and at least chlorine-containing powder is supplied in the treatment tank 2. The body P1 and the first desalting washing liquid W1 are mixed and made into a slurry, and the slurry S1 is stirred for a predetermined time to dissolve chlorine contained in the chlorine-containing powder P1 in the liquid phase and elute it. I am doing it. In the embodiment shown in FIG. 2, at least the chlorine-containing powder P1 and the first desalting washing liquid W1 are introduced into the treatment tank 2 to be mixed and slurryed, but the slurry is separately prepared. There is no problem even if it is introduced into the processing tank 2.

Further, in the chlorine-containing powder washing treatment system 1 according to this embodiment, the slurry S2 that has been treated in the treatment tank 2 is conveyed to the filter separation / separation device 6 via the slurry transfer device 4. .. In the filter separation device 6, a part or all of the liquid phase is filtered out from the slurry S2 to obtain a desalted cake C1 having a reduced chlorine content. Further, a buffer tank 5 is provided on the upstream side of the filter separation device 6, the slurry S2 conveyed from the processing tank 2 is temporarily stored, and the slurry supply valve 8a having a predetermined valve mechanism is opened at a desired timing. Then, a predetermined amount is supplied to the filter separation device 6. By providing such a buffer tank 5, as described above, it is possible to carry out the washing treatment without disturbing the continuity of introduction of the chlorine-containing powder.

As described above, in the treatment tank 2, at least the chlorine-containing powder P1 and the first desalination washing liquid W1 are mixed and made into a slurry, and the chlorine-containing powder P1 and the first desalting washing liquid W1 at that time are combined with each other. The mass ratio (W1 / P1) of is preferably 4 to 10, more preferably 4 to 7, and particularly preferably 4 to 5. When the mass ratio (W1 / P1) is smaller than 4, the elution of chlorine from the chlorine-containing powder P1 may be insufficient. Further, when the mass ratio (W1 / P1) is larger than 10, the amount of the filtrate generated in the subsequent filtration separation step increases.

The chlorine ion concentration of the first desalting washing liquid W1 which is mixed with the chlorine-containing powder P1 in the treatment tank 2 and constitutes the slurry S1 is preferably 3% by mass or less, more preferably 2% by mass or less, and 1% by mass. The following are particularly preferred. Although the lower limit is not set in particular, the chlorine concentration of industrial water derived from river water, groundwater, etc. is usually about 0.005% by mass. When the chlorine ion concentration of the first desalting washing liquid W1 is larger than 3% by mass, the elution efficiency of chlorine from the chlorine-containing powder P1 in the chlorine elution step depends on the chlorine content of the chlorine-containing powder P1. May decrease.

The pH of the slurry S1 in the chlorine elution step is preferably 6 to 11, more preferably 6 to 10.5, and particularly preferably 6 to 9. Here, since the pH of the slurry S1 is blown with a gas containing carbon dioxide as described later, the pH can be set to 7 or less by dissolving the carbon dioxide in the gas, but the pH adjuster is applied to the slurry S1. pH 1 may be added. By adding the pH adjuster pH 1, the pH of the slurry S1 can be adjusted to 6 to 9, and chlorine elution from the sparingly soluble Friedel salt contained in the ash dust can be effectively generated. As the pH adjuster pH 1, dilute sulfuric acid, hydrochloric acid or the like can be used.

As shown in FIG. 2, in the water washing treatment system 1 for chlorine-containing powder according to this embodiment, a tubular air diffuser 3 is attached to the treatment tank 2. The tubular air diffuser 3 is composed of a nozzle 31 for injecting the gas A1 through which the air supply pipe 33 for supplying the gas A1 containing carbon dioxide communicates with the gas A1, and a cylindrical cylindrical tube 32 for arranging the nozzle 31 at the inner end. It is configured. Then, the gas A1 blown from the nozzle 31 rises upward together with the slurry while entraining the slurry inside the cylinder of the cylindrical tube 32, becomes a mixed jet of the gas A1 and the slurry S1, and becomes the upper end opening of the cylindrical tube 32. It is designed to be ejected from 32a. On the other hand, from the lower end opening 32b of the cylindrical tube 32, as the slurry inside the cylinder rises upward, the lower side inside the cylinder of the cylindrical tube 32 becomes negative pressure as compared with the upper side, so that the treatment tank 2 has a negative pressure. The slurry staying on the bottom side is sucked into the inside of the cylinder of the cylinder tube 32. By such a mechanism of the tubular air diffuser 3, the gas A1 recirculates in the slurry housed in the treatment tank 2 while entraining the slurry S1 over the lower layer and the upper layer thereof. Is formed so that the entire slurry contained in the treatment tank 2 is agitated.

More specifically, the mechanism of the tubular air diffuser 3 will be described in more detail. Due to the air lift effect generated by the blowing of the gas A1 from the nozzle 31, a difference in specific gravity is formed between the slurry inside and outside the cylinder of the cylindrical tube 32. Then, a mixed jet of the slurry and the gas is generated in the cylinder of the cylindrical tube 32. The shape of the gas in the mixed jet has an arbitrary diameter due to the shape of the nozzle 31 for blowing into the slurry, shearing due to collision with the slurry when blown from the nozzle 31, or after being blown. It is in the form of bubbles. The speed of the mixing stirring flow flowing in the cylinder of the cylindrical tube 32 is preferably 1 m / sec or more, more preferably 2 m / sec or more, and particularly preferably 3 m / sec or more. Although there is no upper limit to the speed of this mixing stirring flow, it is preferably 15 m / sec or less from the viewpoint of preventing sudden ejection of the slurry S1 from the treatment tank 2. When the speed of the mixing stirring flow flowing in the cylinder of the cylindrical tube 32 is less than 1 m / sec, the formed stirring flow becomes weak and it becomes difficult to stir the entire slurry S1 contained in the processing tank 2. In some cases.

Further, the cylindrical tube 32 of the tubular air diffuser 3 may adopt a substantially conical structure in which the inner diameter thereof decreases from the lower end side where the nozzle 31 is arranged toward the upper end opening 32a. According to this, the ejection pressure of the mixed jet from the upper end opening 32a can be further increased.

Further, a structure such as a protrusion or a spacer is provided inside the cylinder of the cylindrical tube 32 of the tubular air diffuser 3 so as to partially block the flow of the mixed jet, and the means for generating turbulence by the structure is provided. You may try to do it. According to this, it is possible to easily generate bubbles due to the cavitation effect.

Here, it can be said that the cavitation effect is a phenomenon in which a vacuum cavity is generated due to a pressure difference in a microscopic local region of the fluid and becomes fine bubbles, and is a phenomenon that can generally occur in a fluid in general. Therefore, the cavitation bubbles can be generated by the shape of the nozzle 31 and the cylindrical tube 32 of the cylindrical air diffuser 3, the upper end opening 32a and the lower end opening of the cylindrical tube 32, even if there is no special turbulent flow generating means by the above structure. Due to the shape of 32b and the like, it may occur in the above slurry.

In the present invention, the mixed jet formed by the tubular air diffuser 3 and the mixed stirring flow of the slurry and the gas formed by refluxing the mixed jet over the lower and upper layers of the slurry contained in the treatment tank 2 are used. May contain bubbles due to the above cavitation effect. Bubbles due to the cavitation effect generate a high impact pressure of several GPa in a local region on the order of several μm at the time of collapse, and a temperature of several thousand ° C is microscopically generated by adiabatic compression at the time of bubble collapse. Therefore, the decay impact force of the cavitation bubbles has the effect of destroying the solid-phase aggregates present in the slurry S1. Further, the heating at the time of decay of the cavitation bubbles has an effect of improving the elution efficiency of chlorine from the chlorine-containing powder P1.

In order to form a more effective stirring flow, the treatment tank 2 may be equipped with a plurality of tubular air diffusers 3 as described above. In this case, by unifying the ejection directions of the mixed jets by the plurality of tubular air diffusers 3 in the vertical direction of the processing tank 2, it is possible to effectively stir the entire inside of the processing tank 2. .. Further, the processing tank 2 may be provided with a tubular air diffuser 3 and may be further equipped with a general-purpose stirring blade in combination.

As the slurry transfer device 4 for transferring the slurry S1 from the processing tank 2 to the buffer tank 5, a general-purpose slurry pump such as a screw pump or a mono pump may be used, but in the embodiment shown in FIG. 2, the processing tank An inclined gutter is installed at the place where the overflow of 2 occurs. By doing so, the amount of the slurry S1 to be increased by the chlorine-containing powder P1 and / or the first desalting washing liquid W1 which may be continuously supplied to the treatment tank 2 is increased according to the increased amount. The slurry S2 overflowing from the processing tank 2 is automatically transferred to the buffer tank 5.

The buffer tank 5 is not limited in its mechanism and material as long as it can store a predetermined amount of slurry S2 and appropriately supply it to the filter separation device 6.

The filter separation device 6 may be any device that can filter out a part or all of the liquid phase from the slurry S2 that has been treated in the treatment tank 2, and a filter press or the like is preferably exemplified. Also in the embodiment shown in FIG. 2, a filter press is used as the filter separation device 6. In such a filter separation device 6 (filter press), the introduced object to be treated is solid-liquid separated by a filter cloth to obtain a dehydrated cake whose water content is usually reduced to about 50% by mass. At that time, the pressure in the squeezing for adjusting the thickness and the water content of the dehydrated cake (the squeezing at the time of introducing the object to be treated may be referred to as "primary squeezing") may be 0.2 MPa to 2 MPa. The opening of the filter cloth may be any as long as it can collect a solid phase having a particle size of 0.1 μm or more, and the pressing method, the type of the filter cloth, and the like are not particularly limited. In the embodiment shown in FIG. 2, when the slurry S2 is introduced into the filter separation device 6 (filter press), the slurry S2 is pressurized by the slurry supply pump 7a having a predetermined pump mechanism. Can be done. That is, it is possible to press-fit the object to be processed, whereby the slurry S2 can be introduced into the filter separation device 6 (filter press) more quickly. Further, since the water removed when the slurry S2 is introduced into the filter separation device 6 (filter press) is discharged as the first filtrate W3, in the embodiment shown in FIG. 2, this is used as a predetermined valve. The filtrate discharge valve 8c having a mechanism is opened so that the filtrate can be discharged to the outside of the system.

Further, in the filter separation device 6 (filter press), the dehydrated cake once obtained by solid-liquid separation and having a water content of about 50% by mass is washed with the second demineralizing washing liquid W2. Then, almost all of the liquid phase contained in the dehydrated cake is replaced with the second demineralized washing liquid W2 (in the case of washing by circulating the washing liquid in the direction in which the object to be treated is introduced and in the forward direction). Is also referred to as "normal cleaning", and is also referred to as "reverse cleaning" when the washing liquid is circulated in the direction opposite to the direction in which the object to be treated is introduced.) This makes it possible to more reliably desalt the dehydrated cake. The chlorine ion concentration of the second desalting washing liquid W2 is preferably lower than that of the first desalting washing liquid W1, more specifically, 0.5% by mass or less, preferably 0.3. It is more preferably 0% by mass or less, and particularly preferably 0.1% by mass or less. Although the lower limit is not set in particular, the chlorine concentration of industrial water derived from river water, groundwater, etc. is usually about 0.005% by mass.

In the embodiment shown in FIG. 2, the second desalting washing liquid W2 is a predetermined valve from the second desalting washing liquid supply tank 61 attached to the filter separation device 6 (filter-press) at a desired timing. The second desalting washing liquid supply valve 8b having a mechanism is opened to supply the liquid. At that time, the second desalting washing liquid W2 can be pressurized by the second desalting washing liquid supply pump 7b having a predetermined pump mechanism. That is, it is possible to pressurize and introduce the second desalting washing liquid W2, whereby the dehydrated cake can be washed more quickly by the second desalting washing liquid W2. Further, during or after washing with the second desalting washing liquid W2, the dehydrated cake is squeezed to adjust the thickness and water content in the same manner as the primary squeezing treatment at the time of introducing the slurry S2 described above. (The squeezing during or after washing the dehydrated cake may be referred to as "secondary squeezing").

In the embodiment shown in FIG. 2, the second filtrate W4 produced by washing the dehydrated cake with the second desalting washing liquid W2 in the filter separation device 6 is a filtrate return pump 7c having a predetermined pump mechanism. The liquid is sent to the storage portion of the dewatering washing liquid supply device 22 and reused as the first dewatering washing liquid W1. According to this, the amount of water used for the desalting washing liquid can be saved. When the concentration of chlorine or the like rises due to the reuse of the washing liquid, the filtrate discharge valve 8c having a predetermined valve mechanism is opened so that the chlorine and the like can be discharged to the outside of the system. As described above, since the concentration of chlorine and the like in the first filtrate generated at the time of introduction into the filter separation device 6 (filter press) is relatively high, the filtrate discharge valve 8c is basically used. Is discharged to the outside of the system by opening the cap, but in some cases, the liquid is sent to the storage portion of the desalination washing liquid supply device 22 and the first desalting is performed in the same manner as the second filtrate W4. It may be reused as a washing liquid W1.

Further, as shown in FIG. 2, in the chlorine-containing powder washing treatment system 1 according to this embodiment, the desalted cake C1 obtained by the filter separation device 6 is conveyed to the cement manufacturing device 9 for cement. I try to use it as a raw material. At that time, a general-purpose device such as a belt conveyor, which can convey a cake having a water content of about 50% by mass, may be used.

Further, as shown in FIG. 2, in the chlorine-containing powder washing treatment system 1 according to this embodiment, the carbon dioxide-containing gas A2 discharged from the cement manufacturing apparatus 9 is transferred to the tubular air diffuser 3. It is supplied and used as a part or all of the gas A1 containing carbon dioxide. According to this, the slurry in the chlorine elution step can be heated by the amount of heat contained in the gas discharged from the cement manufacturing apparatus 9, and the elution efficiency of chlorine from the chlorine-containing powder P1 can be improved. can.

As described above, according to the present invention, solid-state particles having a relatively large particle size are obtained by adopting a specific stirring means when stirring a slurry formed by adding at least water to a chlorine-containing powder. However, it does not stay on the bottom side of the processing tank 2 and can be well dispersed in the entire slurry S1 contained in the processing tank 2. As a result, a state in which the particle size distribution of the solid phase particles of the solid phase contained in the slurry is wide and well dispersed is formed, and the particle size is relatively relatively small in the filtration separation step by the filtration separation device 6. The large solid-phase particles of the above are the nuclei, and the solid-phase particles of relatively small particle size are also combined to form a packed structure having appropriately communicated interparticle voids, and a good filtration rate is exhibited. Due to this excellent filtration rate, the time required for the filter separation device 6 is significantly shortened, and the chlorine-containing powder P1 can be efficiently washed with water. Here, the solid phase particles may contain calcium carbonate due to a chemical reaction between the calcium component dissolved in the slurry S1 and the carbon dioxide in the gas A1 blown into the slurry S1.

According to the examples described later, when a filter press is used as the filter separation device 6, the time required for press-fitting the slurry, normal washing (washing with water), primary pressing, back washing (washing with water), and secondary pressing. Of these, the time required for the press-fitting and backwashing processes was significantly reduced. Therefore, it is considered that the configuration of the present invention greatly contributes to improving the filtration rate in the process of dehydration from the slurry-like composition through a filter-separated separation member such as a filter cloth. Further, the required time can be typically shortened to, for example, 25 minutes or less, more typically, for example, 22 minutes or less, and even more typically 20 minutes or less. It is possible to shorten it to the following, and it is considered that this will sufficiently improve the operational efficiency of the washing process.

Hereinafter, specific test examples will be shown to explain the present invention in more detail, but the present invention is not limited to the embodiments of these test examples.

[Test Example 1]
In the configuration of the water washing treatment system 1 for the chlorine-containing powder shown in FIG. 2, it was evaluated how the equipment specifications of the chlorine elution step in the treatment tank 2 affect the required time of the filtration separation step.

As the chlorine-containing powder P1, molten fly ash (Cl: 12.8% by mass, Pb: 2600 ppm, Zn: 15600 ppm) generated from a gasification and melting furnace was used (hereinafter referred to as “molten fly ash P2”). .. Further, tap water was used as the first desalting washing liquid W1 for slurrying the molten fly ash P2 and the second desalting washing liquid W2 for washing the dehydrated cake. Further, as the treatment tank 2, a tank having a capacity of 3.5 m ³ was used.

A filter press (air permeability of the filter cloth: 1000 cm / min, thickness of the filter cloth: 1.8 mm, filter cloth: Ayaori cedar of polypropylene) was used for the filter separation device 6, and the solid-liquid ratio of the slurry S1 ("" The mass ratio of the first desalination washing liquid W1 / molten flying ash P2 ”is set to 4, and the solid-liquid ratio of the desalted cake C1 at the time of washing with the second desalting washing liquid W2 in the filter separation device 6. (Mass ratio of "second desalting washing liquid W2 / molten flying ash P2") was set to 1, and the water content of the desalted cake C1 obtained by the treatment was set to 50% by mass.

Table 1 summarizes the equipment specifications of the chlorine elution process and the pH of the slurry in each specification for each level used for evaluation. Specifically, in Example 1, a level is provided in which the gas A1 is supplied and the slurry S1 is agitated only by the tubular air diffuser 3, and in Comparative Example 1, the gas A1 is supplied by the tubular air diffuser. Instead of 3, a disc-type air diffuser installed in the processing tank 2 is used to blow fine bubbles, and a stirring blade arranged in the processing tank 2 is used to stir the slurry S1. , Without supplying the gas A1, only the stirring of the slurry S1 is performed by the stirring blade arranged in the processing tank 2 instead of the tubular air diffuser 3, and each equipment specification is separated by filter. We evaluated how it affects the time required for the process. For supplying the gas A1 to the slurry S1, a tubular air diffuser (Aqua Blaster AL-1500, manufactured by Ayence Co., Ltd.) was used in Example 1, and an air diffuser (Teller C type, manufactured by Erastocks Co., Ltd.) was used in Comparative Example 1. Made) was used. Further, a four-blade type having a diameter of 600 mm was used for the stirring blade.

Table 2 summarizes the time required for the filtration separation step and the filtration rate (kg / hr) per unit area (m ² ) of the filter cloth involved in the filtration separation for each of the above levels. The required time is summarized for each of the following press-fitting, normal cleaning, primary pressing, back-cleaning, and secondary pressing processes related to the work process of the filter press.

(Press-fit)
The slurry was poured into the filter separation chamber surrounded by the filter cloth of the filter press through a pipe connected to the introduction port where the filter cloth enclosure of the filter separation chamber was partially unraveled, and the slurry was filtered by the filter cloth. A step of filling a certain amount of slurry with a predetermined pressure while discharging the filtrate W3 from the discharge port side / In this test example, about 20 L of slurry is prepared per filter separation chamber under a pressure condition of 0.3 MPa. Filled up.

(Correct cleaning)
Step of washing with the second desalting washing liquid W2 through the pipe into which the slurry was charged / In this test example, it was set to 0.3 MPa × 1 minute, which was fixed between each level.

(Primary squeezing)
A process of adjusting the thickness and water content of the dehydrated cake by applying a predetermined pressure to the filter plates arranged so as to sandwich the cake layer through the filter cloth surrounding the filter separation chamber of the filter press / 0.3 MPa in this test example. The setting was fixed at x4 minutes and between each level.

(Backwash)
A step of introducing the second dewatering washing liquid W2 into the dehydrated cake and washing it through the pipe on the discharge port side of the filtrate from the filter separation chamber of the filter press in the opposite direction to the normal washing / the second in this test example. Backwashing was performed until the electric conductivity of the filtrate W4 became 900 mS / m (when the backwashing filtrate has the above electric conductivity, the chlorine content of the obtained dewatered cake C1 is about 0.5% by mass. You can expect it.).

(Secondary squeezing)
After backwashing, a predetermined pressure is applied to the filter plates arranged on the outside so as to sandwich the cake layer through the filter cloth surrounding the filter separation chamber of the filter press, and the thickness and water content of the dehydrated cake are adjusted. In the test example, it was set to 0.7 MPa × 4 minutes, which was fixed between each level.

As shown in Table 2, in Example 1 in which the tubular air diffuser 3 was used as the specification of the treatment tank 2 in the chlorine elution step, the time required for the filter separation separation step by the filter press was 3 minutes by press fitting. It took 8 minutes for backwashing, which took 20 minutes in total, whereas in Comparative Example 1 using a diffuser and a stirring blade as the specifications of the treatment tank 2 in the chlorine elution step, press-fitting was performed. It took 5 minutes, 13 minutes for backwashing, and 27 minutes in total, which took longer. In Comparative Example 2 in which only the stirring blade was used as the specification of the treatment tank 2 in the chlorine elution step, 7 was press-fitted. It took minutes, backwashing took 16 minutes, and the total time was 32 minutes, which was even longer. Further, when the filtration rate (kg / m ² / hr), which is an index of the processing capacity, was obtained, it was 14.1 in Example 1, 10.1 in Comparative Example 1, and 9.4 in Comparative Example 2, and chlorine elution was obtained. It was clarified that when the slurry S1 was stirred and the gas A1 was supplied in the treatment tank 2 in the step by using the tubular air diffuser 3, the water washing treatment ability of the chlorine-containing powder was significantly improved.

[Test Example 2]
The particle size distribution of the solid phase component of the desalted cake C1 obtained at each level of Test Example 1 was examined with a laser diffraction / scattering type particle size distribution measuring device. The results are shown in FIG.

As shown in FIG. 3, the solid phase component of Comparative Example 1 has many fine particles and the solid phase component of Comparative Example 2 has many coarse particles, whereas the solid phase component of Example 1 has many solid phase components. The particle size distribution of the particles was relatively in the middle of Comparative Example 1 and Comparative Example 2. This is because, in Comparative Example 1, calcium carbonate generated by the supply of gas A1 containing carbon dioxide is particles having a relatively fine particle size, but in the combination of the diffuser and the rotary blade, the entire treatment tank 2 is sufficiently agitated. However, due to the fact that the overflow from the treatment tank 2 contains a large amount of calcium carbonate particles, in Comparative Example 2, the molten flying ash P2 used as the chlorine-containing powder P1 was used in the stirring using only the stirring blade. It was considered that this was due to the fact that the contained solid phase content remained in the aggregated state. On the other hand, in the first embodiment using the tubular air diffuser 3, the first is a slurry in which the gas A1 recirculates while entraining the slurry S1 over the lower and upper layers of the slurry S1 contained in the processing tank 2. Secondly, the supply of the gas A1 containing carbon dioxide is caused by the fact that a mixed stirring flow with the gas is formed and the entire slurry S1 contained in the treatment tank 2 can be sufficiently stirred. It is considered that the slurry S2 overflowing from the treatment tank 2 was formed in a state in which the particle size distribution of the solid phase particles for the solid phase was wide and well dispersed due to the generation of calcium carbonate particles. rice field.

1 Water washing treatment system for chlorine-containing powder 2 Treatment tank 3 Cylindrical air diffuser 4 Slurry transfer device 5 Buffer tank 6 Filter separation device 7a Slurry supply pump 7b Second desalination washing liquid supply pump 7c Sulfate return pump 8a Slurry Supply valve 8b 2nd desalination wash liquid supply valve 8c Sulfate discharge valve 9 Cement production equipment 21 Chlorine-containing powder supply equipment 22 1st desalination wash liquid supply equipment 23 pH adjuster supply equipment 31 Nozzle 32 Cylindrical tube 33 Send Air tube 61 2nd desalting washing liquid supply tank A1, A2 Gas containing carbon dioxide P1 Chlorine-containing powder P2 Molten flying ash S1, S2 Slurry C1 Desalting cake W1 1st desalting washing liquid W2 2nd desalting Washing liquid W3 1st filtrate W4 2nd filtrate pH1 pH adjuster

Claims (10)

A chlorine-containing powder introduction step in which a slurry formed by adding at least water to a chlorine-containing powder is stored in a treatment tank having a predetermined capacity.
A chlorine elution step of stirring the slurry contained in the treatment tank to elute the chlorine contained in the chlorine-containing powder into the liquid phase.
A filter separation step for obtaining a desalted cake by filtering a part or all of the liquid phase from the slurry after chlorine elution is provided.
In the stirring of the slurry in the chlorine elution step, a gas containing carbon dioxide is blown into the slurry contained in the treatment tank, and the gas recirculates while entraining the slurry over the lower and upper layers of the contained slurry. A method for washing chlorine-containing powder with water, which is carried out by forming a mixed stirring flow of the gas and the slurry.
The gas containing carbon dioxide is blown into the slurry contained in the treatment tank by a tubular air diffuser.
The tubular air diffuser is provided with a cylindrical cylindrical tube having openings at both ends and a nozzle for passing carbon dioxide-containing gas arranged at one end thereof.
The tubular air diffuser is provided so that the nozzle is arranged on the lower side in the processing tank.
The gas containing carbon dioxide is introduced into the cylinder of the cylinder through the nozzle of the tubular air diffuser, and the slurry is sucked into the inside of the cylinder from the lower opening of the cylinder. A method for washing a chlorine-containing powder with water so that the gas and the slurry are mixed and ejected from the upper opening of the cylindrical tube by being introduced . The treatment tank is configured such that the slurry contained in the treatment tank overflows in response to the chlorine-containing powder additionally introduced and is carried out for the filtration separation step. The method for washing a chlorine-containing powder according to claim 1. The method for washing a chlorine-containing powder according to claim 1 or 2, wherein the liquid phase is separated by a filter press in the filter separation step. The method for washing a chlorine-containing powder according to claim 1 or 2, wherein the chlorine-containing powder contains one or more selected from incineration fly ash, molten fly ash, and cement kiln dust. The method for treating a chlorine-containing powder according to claim 1 or 2, wherein the washing treatment with water can be performed according to the chlorine-containing powder continuously introduced. A treatment tank having a predetermined capacity for accommodating a slurry made by adding at least water to a chlorine-containing powder, and a treatment tank.
A gas containing carbon dioxide is blown into the slurry provided in the treatment tank and contained in the treatment tank, and the gas recirculates while entraining the slurry over the lower and upper layers of the contained slurry. A tubular air diffuser for forming a mixed stirring flow with the slurry, and
A chlorine-containing powder washing treatment system comprising a filter separation device for filtering a part or all of the liquid phase from the slurry taken out from the treatment tank to obtain a desalted cake .
The tubular air diffuser is provided with a cylindrical cylindrical tube having openings at both ends and a nozzle for passing carbon dioxide-containing gas arranged at one end thereof.
The tubular air diffuser is provided so that the nozzle is arranged on the lower side in the processing tank.
The gas containing carbon dioxide is introduced into the cylinder of the cylinder through the nozzle of the tubular air diffuser, and the slurry is sucked into the inside of the cylinder from the lower opening of the cylinder. A water washing treatment system for chlorine-containing powder, which is configured to be introduced to form a mixed jet of the gas and the slurry and ejected from the upper opening of the cylindrical tube . The treatment tank is configured such that the slurry contained in the treatment tank overflows in response to the chlorine-containing powder additionally introduced and is carried out to the filter separation device. The water washing treatment system for chlorine-containing powder according to claim 6. The chlorine-containing powder washing treatment system according to claim 6 or 7, wherein the filter separation device is a filter press. The water washing treatment system for chlorine-containing powder according to claim 6 or 7, further comprising a transport device for transporting the obtained desalted cake to a cement manufacturing facility. The water washing treatment system for chlorine-containing powder according to claim 6 or 7, wherein the water washing treatment can be performed according to the chlorine-containing powder continuously introduced.

Images