TW202337562A - Method for desalting treatment of chlorine-containing powder - Google Patents

Abstract

Provided is a method for a desalting treatment of a chlorine-containing powder, whereby it becomes possible to effectively reduce the amount of water to be used in the entire system. The method for a desalting treatment of a chlorine-containing powder is configured such that a slurrying step, a chlorine elution step, a desalted cake formation step, a first desalted cake washing step and a second desalted cake washing step are repeated for each chlorine-containing powder to be supplied, in which at least a portion of a third filtrate obtained in the second desalted cake washing step is collected and stored, and is reused as a wash solution for second desalting for the first desalted cake washing step or a wash solution for third desalting for the second desalted cake washing step or both of the wash solutions for a chlorine-containing powder to be supplied in a subsequent stage, and is used circulatively as a wash solution for first desalting for the slurrying step after one reuse or a plurality of reuses.

Description

Desalination treatment method for chlorine-containing powder

The present invention relates to a desalination treatment method for reducing the chlorine content of chlorine-containing powders such as incineration ash.

Incineration ash generated when municipal waste such as general waste and industrial waste is incinerated, or clinker dust generated from cement plants, etc., are being effectively reused as cement raw materials from the viewpoint of resource and environmental protection. However, these powders contain a large amount of chlorine. Since the chlorine will hinder the quality of cement and the normal operation of cement manufacturing equipment, desalination treatment is required when used as cement raw materials. Furthermore, at this time, a large amount of wash water is required for cleaning, and reducing the amount of water used has become a problem.

Regarding these problems, for example, Patent Document 1 (Japanese Patent Application Publication No. 2003-211129) discloses a method for cleaning ash, which is characterized by providing a plurality of cleaning steps. The cleaning step consists of mixing ash and water. The mixing device is composed of a mixing device and a solid-liquid separation device that separates the mixture from the aforementioned mixing device into ash and water. The ash is washed in multiple stages to countercurrent the flow of ash and water. At the same time, the solid-liquid separation in the first stage is The ash separated from solid and liquid in the separation device is dehydrated until the moisture content of the wet ash does not reach 60%. Furthermore, desalination from ash can be effectively achieved with a small amount of wash water (paragraph 0021 of Patent Document 1).

Furthermore, for example, Patent Document 2 (Japanese Patent Application Laid-Open No. 2005-246295) discloses an incineration ash processing device, which is a drum filter equipped with multiple stages for washing incineration ash, and supplies new washing water in the final stage. The feature of the incineration ash treatment device is the drum filter in each of the above-mentioned stages, which uses the recovered wash water that is suctioned and recovered in each stage as wash water in the previous stage to wash the incineration ash transported from the first stage to the final stage. It is equipped with a recovered wash water supply means that sucks and recovers a part of the previously recovered wash water through the drum filter, and supplies the previously recovered wash water to a position upstream of the drum rotation direction with respect to the segment. The aforementioned mixture is placed around the periphery of the aforementioned filter. Furthermore, while achieving the same cleaning effect as before, the number of drum filter stages can be reduced and the amount of water used can be reduced (Patent Document 2, paragraph 0014) [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2003-211129 [Patent Document 2] Japanese Patent Application Publication No. 2005-246295

[Problem to be solved by the invention]

In the above-mentioned Patent Documents 1 and 2, in the desalination treatment of chlorine-containing powder such as incineration ash, washing water is added to the powder to dissolve chlorine into the liquid phase and the dehydrated desalted cake is used in order to effectively remove the moisture in the cake as The amount of chlorine remaining in the residue, and by setting up multiple stages of cleaning devices to remove the amount of residual chlorine, the amount of water used can be reduced.

However, according to the inventor's knowledge, if a multi-stage cleaning device is installed to clean the desalted cake as in the above-mentioned Patent Documents 1 and 2, a huge amount of water will be used to clean the residual ash attached to the filter cloth and the device itself. However, there is a problem that the overall water usage of the system cannot be suppressed.

Therefore, an object of the present invention is to provide a desalination treatment method for chlorine-containing powder that can effectively reduce the amount of water used in the entire system. [Means used to solve problems]

In order to achieve the above object, the first series of the present invention provides A desalination treatment method for chlorine-containing powder, which has the following steps: The slurrying step is to mix the first desalination washing liquid with chlorine-containing powder to form a slurry. The chlorine dissolution step of dissolving the chlorine contained in the aforementioned chlorine-containing powder in the aforementioned slurry into the liquid phase, The desalting cake forming step of obtaining the first desalting cake and the first filtrate through the aforementioned dehydration of the chlorine-eluted slurry, The first desalting cake washing step is to wash the aforementioned first desalting cake with a second desalting washing liquid that is different from the aforementioned first desalting washing liquid to obtain a second desalting cake and a second filtrate, and The aforementioned second desalting cake is washed with a third desalting washing liquid that is different from the aforementioned first desalting washing liquid and the second desalting washing liquid, to obtain a washed second desalting cake of the third desalting cake and the third filtrate. steps, The aforementioned slurrying step, the aforementioned chlorine dissolution step, the aforementioned desalted cake forming step, the aforementioned first desalted cake washing step and the aforementioned second desalted cake washing step are repeated for each supply of chlorine-containing powder. At least part of the third filtrate obtained in the second desalting cake washing step is recovered and stored, and is reused as the second filtrate in the first desalting cake washing step corresponding to the chlorine-containing powder supplied to the subsequent stage. The desalting washing liquid, the third desalting washing liquid used in the second desalting cake washing step, or both, are recycled as the first desalting washing liquid after being reused once or multiple times. .

According to the above desalination treatment method of chlorine-containing powder, since the first desalination washing liquid is mixed with the chlorine-containing powder to form a slurry, the chlorine contained in the chlorine-containing powder is dissolved into the liquid phase of the slurry. The slurry is dehydrated to obtain a first desalted cake and a first filtrate, and the first desalted cake is washed with a second desalted washing liquid different from the first desalted washing liquid to obtain a second desalted cake and a second desalted liquid. filtrate, and then wash the second desalting cake with a third desalting washing liquid that is different from the first desalting washing liquid and the second desalting washing liquid to obtain a third desalting cake and a third filtrate, thereby obtaining The third desalting cake with sufficient chlorine removed. Therefore, it is useful for cement raw materials such as incineration ash containing chlorine. Moreover, at least part of the third filtrate obtained in the second desalting cake washing step is recovered and stored, so even if there is no multi-stage device for washing the desalting cake, it can still be used as chlorine-containing powder supplied to the subsequent stages. The desalination lotion corresponding to the body is reused. Moreover, since it is recycled as the first desalination wash liquid after one or multiple reuses, the desalination effect of the chlorine-containing powder by the desalination treatment can be maintained, and the water consumption of the entire system can be reduced. Furthermore, by reducing the amount of water used, the amount of heavy metals eluted can be suppressed.

In order to achieve the above object, the second aspect of the present invention provides the desalination treatment method. In the desalination treatment method for chlorine-containing powder, the desalination cake forming step, the first desalination cake washing step and the second desalination cake washing step are It is carried out with a solid-liquid separation device using a filter cloth, and at least a part of the filter cloth washed drainage water obtained after the aforementioned filter cloth is washed is circulated as the aforementioned second desalination washing liquid, the aforementioned third desalination washing liquid, or both of them. use.

According to the above configuration, since a solid-liquid separation device using a filter cloth is used, desalting cake formation from the slurry and subsequent cleaning of the entire supplied large-capacity chlorine-containing powder can be effectively performed. Moreover, in order to prevent the filter cloth of the solid-liquid separation device used from being clogged and it must be washed frequently during the operation of the entire device, the washed drainage water can be recycled as the second desalination washing liquid and the third desalination washing liquid. liquid or both, so the overall water usage of the system can be further reduced.

In order to achieve the above object, the third aspect of the present invention provides the desalination treatment method. In the desalination treatment method of chlorine-containing powder of the second configuration, the solid-liquid separation device is a filtration press or a belt filter.

According to the above structure, an existing device system can be used as a solid-liquid separation device.

In order to achieve the above object, the fourth aspect of the present invention provides the desalination treatment method. In the desalination treatment method of chlorine-containing powder of the second configuration, the solid-liquid separation device is a filter press, and the filter cloth is washed and drained at least A part is subjected to solid-liquid separation, and the liquid portion is recycled as the second desalting washing liquid, the third desalting washing liquid, or both.

According to the above structure, an existing device system can be used as a solid-liquid separation device using filter cloth. In addition, although the filter press is a device that can clean the cake, the general cake washing device is to pass water from the anti-filtration surface side of the filter cloth. Therefore, since the filter cloth washed and drained water containing solid content is directly used in the cake washing water (used in the second and third desalination washing liquids), which causes clogging of the filter cloth, the filter cloth is washed and drained. Solid-liquid separation can be appropriately used as the second and third desalting washing liquids.

In order to achieve the above object, the fifth aspect of the present invention provides the desalination treatment method. In the above desalination treatment method of chlorine-containing powder, the aforementioned desalted cake forming step, the aforementioned first desalted cake washing step and the aforementioned second desalted cake washing step are provided. It is carried out using a solid-liquid separation device using a filter cloth, and at least a part of the filter cloth-washed drainage water obtained after washing the filter cloth is recycled as the first desalination washing liquid.

According to the above configuration, since a solid-liquid separation device using a filter cloth is used, desalting cake formation from the slurry and subsequent cleaning of the entire supplied large-capacity chlorine-containing powder can be effectively performed. Moreover, in order to prevent the filter cloth of the solid-liquid separation device used from being clogged and it must be washed frequently during the operation of the entire device, the washed drainage water can be recycled as the first desalination washing liquid, so it can be further reduced. Total water usage of the system.

In order to achieve the above object, the sixth aspect of the present invention provides the desalination treatment method. In the above desalination treatment method of chlorine-containing powder, When reusing the aforementioned third filtrate obtained in the aforementioned second desalting cake washing step, observe any one or more of the following (1) to (5) in the storage tank in which at least a part of the third filtrate is recovered and stored. Decide whether to reuse the aforementioned third filtrate, (1) The total time of the above-mentioned third filtrate reuse treatment (2) The total amount of water processed by the third filtrate reuse mentioned above (3) pH of the aforementioned third filtrate (4) The chloride ion concentration of the aforementioned third filtrate (5) The conductivity of the aforementioned third filtrate.

According to the above structure, when the third filtrate is reused, it is possible to avoid using a washing liquid that is inappropriate for washing the desalted cake.

In order to achieve the above object, the seventh aspect of the present invention provides the desalination treatment method. In the above desalination treatment method of chlorine-containing powder, at least a part of the second filtrate obtained in the first desalination cake washing step is recovered and stored. The second desalting washing liquid corresponding to the chlorine-containing powder supplied to the subsequent stage is used in the first desalting cake washing step and is reused once or multiple times as the first desalting liquid. Recycle with lotion.

According to the above structure, the second filtrate obtained in the first desalting cake washing step is also reused, thereby reliably reducing the water consumption of the entire system. Moreover, since at least part of the above-mentioned second filtrate is recovered and stored, even if there is no multi-stage device for washing the desalted cake, it can be used as a desalting washing liquid corresponding to the chlorine-containing powder supplied to the subsequent stage. Reuse.

In order to achieve the above object, the eighth aspect of the present invention provides the desalination treatment method of chlorine-containing powder of claim 7. In the above desalination treatment method of chlorine-containing powder, When the above-mentioned second filtrate obtained in the above-mentioned first desalted cake washing step is reused, any one or more of the following (1) to (5) may be observed in the storage tank in which at least a part of the second filtrate is recovered and stored. Decide whether to reuse the aforementioned second filtrate, (1) The total time of the above-mentioned second filtrate reuse treatment (2) The total amount of water processed by the second filtrate reuse mentioned above (3) pH of the aforementioned second filtrate (4) The chloride ion concentration of the second filtrate mentioned above (5) The conductivity of the aforementioned second filtrate.

According to the above structure, when the second filtrate is reused, it is possible to avoid using a washing liquid that is inappropriate for washing the desalted cake.

In order to achieve the above object, the ninth aspect of the present invention provides the desalination treatment method. In the above desalination treatment method of chlorine-containing powder, In the first desalting cake washing step, the washing of the first desalting cake with the second desalting washing liquid is carried out multiple times with the second desalting washing liquid, and/or In the second desalting cake washing step, the washing of the second desalting cake with the third desalting washing liquid is performed a plurality of times with the third desalting washing liquid.

According to the above structure, desalination can be reliably performed by washing the cake multiple times.

In order to achieve the above object, the tenth aspect of the present invention provides the desalination treatment method. In the above desalination treatment method of chlorine-containing powder, The amount of water used is 1.5 to 4 parts by mass relative to 1 part by mass of the dry weight of the chlorine-containing powder to be desalted.

According to the above structure, the amount of water used in the desalination treatment of chlorine-containing powder such as incineration ash can be greatly reduced. Furthermore, by reducing the amount of water used, the amount of heavy metals eluted can be suppressed.

In order to achieve the above object, the eleventh aspect of the present invention provides the desalination treatment method. In the above desalination treatment method of chlorine-containing powder, The aforementioned desalted cake forming step, the aforementioned first desalted cake washing step, and the aforementioned second desalted cake washing step are performed with one solid-liquid separation device.

According to the above configuration, the device configuration can be simplified, thereby reducing initial costs and running costs. In addition, the use of water used to wash away the residual ash attached to the filter cloth or the device body can be suppressed to a minimum.

The target object of the desalination treatment method for chlorine-containing powder of the present invention is not particularly limited as long as it is a powder containing chlorine. Examples include incineration fly ash, fused fly ash, chlorine bypass dust, etc. In the past, these wastes were effectively utilized as cement raw materials after desalination treatment. In the typical municipal waste incineration fly ash, that is, the fly ash generated when household waste is incinerated ("incineration fly ash"), it is generally Chlorine (Cl) is contained in a concentration of approximately 10% to 30% by mass, and fly ash generated from a gasification melting furnace ("molten fly ash") generally contains chlorine in a concentration of approximately 10% to 40% by mass. . On the other hand, chlorine bypass dust, which is dust contained in cement kiln exhaust gas, generally contains chlorine at a concentration of 10% to 40% by mass.

According to the desalination treatment method of chlorine-containing powder of the present invention, the chlorine concentration of the above-mentioned chlorine-containing powder is reduced to about 3% by mass or less, and more typically to about 2% by mass or less. This can be effectively used as a cement raw material, for example. The chlorine concentration of chlorine-containing powder can be measured by well-known methods, for example, potentiometric titration, ion chromatography and fluorescence in accordance with JIS A 1154 "Test method for chloride ions contained in hardened concrete" are preferably used. Basic parameter method of X-ray analysis, etc.

The present invention will be described in more detail below with reference to the drawings.

FIG. 1 is a flow chart showing one embodiment of the desalination treatment method for chlorine-containing powder according to the present invention.

As shown in this embodiment, the desalination treatment method of chlorine-containing powder of the present invention includes the following steps: a slurrying step of mixing the first desalination washing liquid with chlorine-containing powder to form a slurry; The chlorine dissolution step of dissolving the chlorine contained in the chlorine-containing powder into the liquid phase; the desalination cake forming step of obtaining the first desalting cake and the first filtrate by dehydrating the chlorine-dissolved slurry; The desalted cake is washed with a second desalted washing liquid that is different from the first desalted washing liquid to obtain the first desalted cake and the second filtrate; and the obtained second desalted cake is combined with the first desalted cake. The first desalting washing liquid and the second desalting washing liquid are washed with a third desalting washing liquid that is different from the second desalting washing liquid to obtain the third desalting cake and the third filtrate in the second desalting cake washing step.

Mix the first desalination washing liquid with the chlorine-containing powder to make a slurry, or dissolve the chlorine contained in the chlorine-containing powder in the slurry into the liquid phase. You can use a special dissolution tank known to those skilled in the art, etc. conduct. In addition, dehydrating the slurry or adding desalting washing liquid to the desalted cake formed by dehydration for washing can be performed by using a special mixing tank or dehydration device that is well known to those skilled in the art. In addition, the movement of the slurry and the liquid can be carried out by using a fluid supply device, a supply tank, a fluid supply pipe, a specific storage tank, etc. that are well known to those skilled in the art.

Furthermore, the above-mentioned slurrying step, chlorine dissolution step, desalting cake forming step, first desalting cake washing step and second desalting cake washing step are repeated for each supply of chlorine-containing powder (repeated in Figure 1 Paragraph 1, Paragraph 2, Paragraph 3), at this time, at least part of the third filtrate obtained in the second desalting cake washing step is recovered and stored, and is reused as chlorine-containing powder supplied to the subsequent stages. Corresponding desalination lotion. More specifically, it can be reused as the second desalting washing liquid used in the first desalting cake washing step, the third desalting washing liquid used in the second desalting cake washing step, or both of them. Moreover, the third filtrate is recycled once or multiple times as the first desalting washing liquid.

Here, "the chlorine-containing powder supplied to the subsequent stage" means that it is different from the chlorine-containing powder that existed in the same step earlier in time. Therefore, for example, in the embodiment shown in Figure 1, the first stage, the second stage, the third stage and the desalination process are repeated in chronological order, and the third filtrate from the first stage is reused in the second stage, but the other It can also be reused as the second desalination washing liquid, the third desalination washing liquid, or both, corresponding to the chlorine-containing powder supplied in the third step and thereafter.

Furthermore, the steps for washing the desalted cake formed by washing the desalted cake are divided into the first and second steps according to the chronological order of the processing steps. However, it can also be divided into more steps to correspond to these methods. For example, a third desalting cake washing step, a fourth desalting cake washing step, a fifth desalting cake washing step, subsequent desalting cake steps, etc., and more stages of desalting cake washing steps are provided. In this case, it is preferable that the filtrate from the desalting cake washing step with an arbitrary number is reused in the chlorine-containing powder supplied to the later stage according to the number attached in the chronological order of the steps with the same number or the previous one. The number attached is in the desalted cake washing steps.

In the embodiment shown in FIG. 1 , at least a part of the second filtrate obtained in the first desalting cake washing step is recovered and stored, and is reused as the second filtrate corresponding to the chlorine-containing powder supplied to the subsequent stage. 1. Desalination cake washing step 2. Desalination washing liquid. And, after the second filtrate is reused once or a plurality of times, it is recycled as the first desalting washing liquid.

The "chlorine-containing powder supplied to the subsequent stage" here means, as mentioned above, that it is different from the chlorine-containing powder that exists in the same step before it according to time. Therefore, for example, in the embodiment shown in Figure 1, although the second filtrate from the first stage is reused in the second stage, it can also be reused as the chlorine-containing powder supplied to the third stage or thereafter. Corresponds to the second desalting washing liquid. Furthermore, the desalting cake washing step may be further provided with multiple stages such as a third desalting cake washing step. In this case, the step of first washing the desalting cake formed by slurry dehydration becomes the first desalting cake washing step. , the desalting lotion used is the second desalting lotion.

In addition, in the desalination treatment method of chlorine-containing powder of the present invention, the reuse of the above-mentioned second filtrate is not an essential component. Furthermore, in the embodiment shown in FIG. 1 , the first filtrate obtained in the desalting cake forming step is treated as wastewater, but if necessary, it may be used as the first filtrate corresponding to the chlorine-containing powder supplied to the subsequent stage. Desalination washing liquid is reused.

In the embodiment shown in Figure 1, all the desalination washing liquid used in the desalination treatment of chlorine-containing powder in the first stage uses new water, which means water newly supplied to the system. As the new water, water other than seawater such as industrial water (fresh water) or chlorine-containing water may be used, as necessary, by adding a chloride ion concentration adjuster such as NaCl or KCl to adjust the chloride ion concentration. However, it cannot be used in large quantities. In areas with industrial water (fresh water), or in situations where the use of industrial water (fresh water) is restricted based on cost, etc., it is more convenient to dilute seawater with industrial water (fresh water) and use it.

In addition, the chloride ion concentration of the desalting washing liquid introduced into the system may increase with reuse. For example, in the case of the first desalting washing liquid, it is preferably suppressed in the range of 3 mass % to 15 mass %. Moreover, in the case of the second desalting washing liquid, it is preferably suppressed to the range of 0.5 mass% to 6 mass%. Moreover, in the case of the third desalting washing liquid, it is preferably suppressed to the range of 0 mass % to 2 mass %.

In an example of the desalting treatment method of chlorine-containing powder of the present invention, FIG. 2 shows a state in which the desalting cake is washed with a desalting washing liquid a plurality of times. That is, in the desalination treatment method of the present invention, for example, as shown in FIG. 2A , the second desalination cake can be washed with the third desalination washing liquid multiple times using the third desalination washing liquid. And as shown in FIG. 2B , the first desalted cake can be washed with the second desalting washing liquid multiple times using the second desalting washing liquid. As shown in FIG. 2C , washing with the second desalting washing liquid is performed a plurality of times, and washing with the third desalting washing liquid is performed a plurality of times. After being used for any number of times, it can be treated as waste water or reused as chlorine-containing powder supplied to the subsequent stages.

Figure 3 shows a state in which the desalting cake forming step, the first desalting cake washing step, and the second desalting cake washing step are performed in one solid-liquid separation device in the desalination treatment method of chlorine-containing powder of the present invention. Specifically, the solid-liquid separation device may be, for example, a filter press or a belt filter. That is, in the example shown in Figure 3, the slurry that has undergone the chlorine dissolution step is introduced into the solid-liquid separation device 1, and is dehydrated according to the normal specifications of the device to obtain the first filtrate. Furthermore, the second desalting washing liquid is introduced into the dehydrated cake held in the device, and is washed according to the normal cleaning specifications of the device to obtain the second filtrate. In addition, the third desalting washing liquid is introduced into the cake washed with the second desalting washing liquid held in the device, and is washed according to the normal cleaning specifications of the device to obtain the third filtrate. Then, the second filtrate and the third filtrate are stored in the storage tank 2 and the storage tank 3 respectively, and can be supplied at a desired time as a washing liquid for supplying the chlorine-containing powder to the subsequent stage.

Moreover, in the example shown in FIG. 3 , the storage tank 2 and the storage tank 3 are respectively provided with a measuring device 4 and a measuring device 5 to observe the properties of the liquid in the tank. Although the observation is not limited, for example, the following (1) to (5) may be used. (1) The total time of the reuse process of the second filtrate or the third filtrate: Use a timer to measure the operation time of the pump for the reuse process. (2) Total water volume treated by reusing the second filtrate or third filtrate: measure the water volume with a flow meter. (3) pH of the second filtrate or third filtrate: measure the pH of the liquid in the tank with a pH meter. (4) Chloride ion concentration of the second filtrate or third filtrate: measure the chloride ion concentration of the liquid in the tank by ion chromatography and potentiometric titration. (5) Conductivity of the second filtrate or third filtrate: measure the conductivity of the liquid in the tank with a conductivity meter.

Furthermore, for example, as the standard for the chloride ion concentration in (4) above, the second desalting washing liquid and the third desalting washing liquid are the same as above. In the case of the second filtrate, it is preferably suppressed to 0.5 mass% to 6 mass%. range. Moreover, in the case of the third filtrate, it is preferable to suppress it in the range of 0 mass % to 2 mass %.

On the other hand, for example, in the case of the second filtrate, as the standard for the total time in (1) above, it is preferably suppressed to the range of 0 minutes to 10 minutes. Moreover, in the case of the third filtrate, it is preferable to suppress it in the range of 0 minutes to 20 minutes.

Moreover, for example, as the standard for the total amount of water in the above (2), the water usage amount is preferably suppressed to 0 to 0 parts by mass relative to 1 part by mass of the dry weight of the chlorine-containing powder to be desalted. The range is 3.5 parts by mass. Moreover, in the case of the third filtrate, it is preferably suppressed to the range of 0 to 3.5 parts by mass.

Moreover, for example, as the pH standard in the above (3), in the case of the second filtrate, it is preferable to keep it within the range of pH7 to pH13. Moreover, in the case of the third filtrate, it is preferable to keep it within the range of pH 7 to pH 12.5.

In addition, for example, as the standard of electrical conductivity in the above (5), in the case of the second filtrate, it is preferably suppressed to the range of 3S/m~30S/m. Moreover, in the case of the third filtrate, it is preferably suppressed to the range of 0S/m ~ 10S/m.

Figure 4 shows another example of the desalination treatment method of chlorine-containing powder of the present invention. That is, in the desalting treatment method of the present invention, for example, as illustrated in FIG. 3 , the solid-liquid separation device 1 is used to combine the desalting cake forming step, the first desalting cake washing step, and the second desalting cake washing step. A solid-liquid separation device is used. At this time, a solid-liquid separation device using filter cloth can also be used. Specifically, the solid-liquid separation device 1 may be, for example, a filter press or a belt filter. Usually, in a solid-liquid separation device using filter cloth, in order to prevent the filter cloth from clogging, it needs to be washed frequently during the entire operation of the device, resulting in a large amount of filter cloth washing and drainage, which is stored in the storage tank 6 in advance as containing water. Chlorine powder lotion can be supplied at the desired time. In this case, since the waste water from washing the filter cloth contains insoluble matter washed away from the used filter cloth, it is treated with the solid-liquid separation device 7 and this liquid part can be used as a washing liquid for the chlorine-containing powder. Especially in the case of filter presses, the filter cloth washing drainage containing solid content is directly used in the cake washing water (used in the second and third desalination washing liquids), which may cause the filter cloth to become clogged. For solid-liquid separation, it can be preferably used as the second and third desalination washing liquids or filter cloth washing washing liquid. The solid-liquid separation device 7 may be, for example, a filter press, a belt filter, a belt press, a vacuum drum filter, a settling tank, or the like.

In the desalination treatment method of chlorine-containing powder of the present invention, although there is no limit, the amount of water used is 1.5 to 4 parts by mass relative to 1 part by mass of the dry weight of the chlorine-containing powder to be desalted. Here, as the "water usage amount", the optimal range of the water amount can be calculated by dividing the amount of water newly supplied to the entire system by the dry weight of the chlorine-containing powder supplied to the system per hour. In addition, the internal amount of water used in each step, including recycled water, is about 1.5 to 7.0 parts by mass for slurrying, and about 0.5 to 5.0 parts by mass for the first desalted cake washing step. parts, used in the second desalting cake washing step is about 0.5 to 5.0 parts by mass. And, as needed, the amount used in the filter cloth cleaning step is about 0.1 to 2 parts by mass.

The present invention is not limited to the above-described embodiments. Various combinations and modifications of the embodiments within the scope disclosed in this specification are possible, and these embodiments are also included in the technical scope of the present invention. [Example]

Hereinafter, the present invention will be explained more specifically by giving test examples. However, the scope of the present invention is not limited to these test examples.

<Test example 1> For the chlorine bypass dust discharged from the cement plant (the chlorine concentration using the basic parameter method of X-ray fluorescence analysis is 20.94%), slurrying, chlorine dissolution, desalination cake formation and desalination are carried out with the specific water amount shown in Table 1 In the cake washing process, at this time, the effect of recycling the drainage from the desalted cake washing was investigated. The test system uses beakers, propeller stirrers and magnetic funnels. Specifically, a specific amount of water and a specific amount of dust are mixed in a beaker to form a slurry. This slurry is formed by using a magnetic funnel equipped with filter paper (quantitative filter paper No. 5c) and a filtrate receiving bottle, using a vacuum pump to depressurize and suck the bottle, and dehydrate the slurry spread on the filter paper. The desalted cake is For cleaning, the desalted cake is spread on the filter paper of the magnetic funnel and the washing liquid used for washing the desalted cake is spread on the desalted cake to wash the cake. Then, separate the desalted cake from the filter paper. After obtaining the desalted cake, install the filter paper on the magnetic funnel again, use a vacuum pump to depressurize the bottle, and spread the washing liquid on the filter paper while washing the filter paper and performing solid-liquid separation.

More specifically, as shown in Figure 5, in Comparative Examples 1 to 7, 1.5 to 5.0 parts by mass of new water (the following The water ratio relative to the dry weight of the chlorine bypass dust is referred to as "1.5 equivalents", etc.). Add 3.5 equivalents, 3 equivalents, 2.5 equivalents, 2 equivalents, 1.25 equivalents or 1 equivalent of new water to the dehydrated desalted cake to wash it. . In addition, 1.5 equivalents of new water are used for washing the filter paper, and 3.5 equivalents, 3 equivalents, and 2 equivalents of the second filtrate discharged from the first stage are used in combination to slurry the chlorine bypass dust for the second stage treatment. Equivalent, 1.25 equivalent or 1 equivalent, and 1.5 equivalent of the filter paper without solid content discharged from the first stage. In addition, in Comparative Example 7, the desalted cake was not washed.

Moreover, as shown in Figure 6, in Examples 1 to 5, 1.5 to 5.0 equivalents of new water were added to the chlorine bypass dust for the first stage treatment to slurry it, and 3.5 equivalents of Use 2.5 equivalents, 1.5 equivalents, 1.25 equivalents or 1 equivalent of new water to wash the desalted cake (the first desalting cake washing), and then repeat the desalting cake washing with the same amount of new water (the second desalting cake washing) . In the same manner as Comparative Examples 1 to 7, 1.5 equivalents of new water were used for washing the filter paper, and 3.5 equivalents of the second filtrate discharged from the first stage were used in combination to slurry the chlorine bypass dust for the second stage treatment. , 2.5 equivalents, 1.5 equivalents, 1.25 equivalents or 1 equivalent, and 1.5 equivalents of the filter paper washed and drained from the first stage. However, in Examples 1 to 5, 3.5 equivalents, 2.5 equivalents, 1.5 equivalents, 1.25 equivalents or 1 equivalent of the third filtrate discharged from the washing of the second desalted cake in the first stage was used to perform the second desalting treatment. 1. Wash the desalted cakes.

On the other hand, as shown in Figure 7, in Example 6, the slurrying, the first desalting cake washing, the second desalting cake washing and the filter paper washing were all performed with 1.5 equivalents of water, but when it was supplied to the second The slurrying of the chlorine bypass dust in the first stage treatment uses the second filtrate discharged from the washing of the first desalting cake in the first stage, and the first desalting cake washing uses the washing of the second desalting cake in the first stage. The third filtrate is discharged cleanly and the second desalted cake is washed and drained using the filter paper discharged from the first stage.

For the washed water after treatment, the chlorine concentration was determined by fluorescence X-ray analysis basic parameter method. Furthermore, ICP analysis (Pb, Zn) and ion chromatography analysis (Cl) of the first filtrate discharged when the desalting cake was formed were performed on the drainage water.

Table 2 summarizes the total amount of new water used in each stage of chlorine bypass dust treatment, and the results of analysis of chlorine concentration and drainage components in the washed product.

The results are as follows.

As shown in Figure 8, the chlorine concentration of the dehydrated cake after washing increased as the new water ratio decreased in both the comparative examples and the examples. However, by recycling the wash water as in the Example, the fresh water ratio (drainage treatment amount) can be reduced with the same chlorine concentration in the dehydrated cake as in the Comparative Example. For example, in Comparative Example 3, the total amount of new water used for each stage of treatment of chlorine bypass dust is 4 equivalents, and the chlorine concentration at this time is 0.59% - dry. In contrast, in Example 1, the When drying with the same chlorine concentration of 0.57% as in Comparative Example 3, it is enough that the total amount of new water is 3 equivalents.

On the other hand, the Pb and Zn components in the wastewater decreased in both the comparative examples and the examples due to the increase in Cl concentration in the wastewater due to the reduction in the fresh water ratio (Figure 9). In addition, by recycling the wash water to reduce the chlorine concentration of the dewatered cake (while maintaining the desalination performance) as in the examples, it is possible to reduce the Pb and Zn concentrations in the wastewater (Figure 10). Therefore, it can be seen that the cost of drainage treatment chemicals required for the treatment of Pb and Zn can be reduced.

In Figure 11, the value obtained by dividing the chlorine concentration of the dehydrated cake by the new water ratio, that is, the residual chlorine concentration per unit water volume, is calculated by subtracting the value of the example from the value of the comparative example when the new water ratio is the same. Create a relationship diagram with the corresponding new water ratio.

As a result, as shown in Figure 11, when the new water ratio is smaller, the desalination treatment effect obtained by recycling the clean water in the example is more significant when compared with the comparative example when the new water ratio is the same.

As can be seen from the above, by recycling clean water, it is possible to reduce the amount of water used in the entire system required to achieve the purpose of desalination treatment.

1: Solid-liquid separation device (for slurry or cake dehydration) 2,3,6:storage tank 4,5: Measuring device 7: Solid-liquid separation device (used to remove cleaning residue from filter cloth)

[Fig. 1] is a flow chart showing one embodiment of the desalination treatment method for chlorine-containing powder of the present invention. [Fig. 2] is a flow chart illustrating a state of washing the desalted cake with a desalting washing liquid in an example of the desalting treatment method of chlorine-containing powder of the present invention. Fig. 2A shows the method of washing the desalted cake. The third desalting washing liquid is used to wash the second desalting cake multiple times with the third desalting washing liquid. Figure 2B shows the state of using the second desalting washing liquid to wash the first desalting cake multiple times with the second desalting washing liquid. As for the state of washing, FIG. 2C shows two states of washing multiple times with the second desalting washing liquid and washing multiple times with the third desalting washing liquid. [Fig. 3] illustrates another example of the desalting treatment method for chlorine-containing powder of the present invention. The desalting cake forming step, the first desalting cake washing step, and the second desalting cake washing step are performed in one solid-liquid separation device. A flowchart of the ongoing process. [Fig. 4] illustrates another example of the desalting treatment of chlorine-containing powder of the present invention. The desalting cake forming step, the first desalting cake washing step, and the second desalting cake washing step are performed in one solid-liquid separation device. , and a flow chart of the state of using a solid-liquid separation device using filter cloth as its solid-liquid separation device. [Fig. 5] is a flow chart illustrating the aspects of Comparative Examples 1 to 7 performed in Test Example 1. [Fig. 6] is a flow chart illustrating the aspects of Examples 1 to 5 performed in Test Example 1. [Fig. 7] It is a flow chart explaining the aspect of Example 6 performed in Test Example 1. [Fig. 8] is a graph showing the relationship between the new water ratio obtained as a result of Test Example 1 and the chlorine concentration of the desalted cake after washing. [Fig. 9] A graph showing the relationship between the chlorine concentration and the Pb concentration in the wastewater component (Fig. 9A) and the relationship between the chlorine concentration and the Zn concentration in the wastewater component (Fig. 9B) obtained as a result of Test Example 1. [Fig. 10] A graph showing the relationship between the chlorine concentration of the desalted cake and the Pb concentration in the drainage component (Fig. 10A) and the relationship between the chlorine concentration of the desalting cake and the Zn concentration in the drainage component (Fig. 10B) obtained as a result of Test Example 1 . [Fig. 11] shows the value obtained as a result of Test Example 1 by dividing the chlorine concentration of the desalted cake by the new water ratio. The difference between the value of the Comparative Example and the value of the Example when the new water ratio is the same is shown. Corresponding graph of the relationship between fresh water ratio.

Claims (11)

A desalination treatment method for chlorine-containing powder, which has the following steps: The slurrying step is to mix the first desalination washing liquid with chlorine-containing powder to form a slurry. The chlorine dissolution step of dissolving the chlorine contained in the aforementioned chlorine-containing powder in the aforementioned slurry into the liquid phase, The desalting cake forming step of obtaining the first desalting cake and the first filtrate through the aforementioned dehydration of the chlorine-eluted slurry, The first desalting cake washing step is to wash the aforementioned first desalting cake with a second desalting washing liquid that is different from the aforementioned first desalting washing liquid to obtain a second desalting cake and a second filtrate, and The aforementioned second desalting cake is washed with a third desalting washing liquid that is different from the aforementioned first desalting washing liquid and the second desalting washing liquid, to obtain a washed second desalting cake of the third desalting cake and the third filtrate. steps, The aforementioned slurrying step, the aforementioned chlorine dissolution step, the aforementioned desalted cake forming step, the aforementioned first desalted cake washing step and the aforementioned second desalted cake washing step are repeated for each supply of chlorine-containing powder. At least part of the third filtrate obtained in the second desalting cake washing step is recovered and stored, and is reused as the second filtrate in the first desalting cake washing step corresponding to the chlorine-containing powder supplied to the subsequent stage. The desalting washing liquid, the third desalting washing liquid used in the second desalting cake washing step, or both, are recycled as the first desalting washing liquid after being reused once or multiple times. . The desalting treatment method for chlorine-containing powder as claimed in claim 1, wherein the desalting cake forming step, the first desalting cake washing step and the second desalting cake washing step are performed by a solid-liquid separation device using filter cloth, At least a part of the filter cloth washed drainage water obtained after the aforementioned filter cloth is washed is recycled as the aforementioned second desalination washing liquid, the aforementioned third desalination washing liquid, or both. Such as the desalination treatment method of chlorine-containing powder of claim 2, wherein the solid-liquid separation device is a filter press or a belt filter. The desalination treatment method of chlorine-containing powder according to claim 2, wherein the solid-liquid separation device is a filter press, and at least a part of the drained water after washing the filter cloth is subjected to solid-liquid separation, and the liquid part is used as the second desalination. The washing liquid, the aforementioned third desalting washing liquid, or both are recycled. The desalting treatment method for chlorine-containing powder according to any one of claims 1 to 4, wherein the aforementioned desalting cake forming step, the aforementioned first desalting cake washing step, and the aforementioned second desalting cake washing step are performed by using a filter cloth. The solid-liquid separation device is used, and at least a part of the filter cloth washed drainage water obtained after the aforementioned filter cloth is washed is recycled as the aforementioned first desalination washing liquid. The method for desalting chlorine-containing powder according to any one of claims 1 to 5, wherein when the above-mentioned third filtrate obtained from the above-mentioned second desalting cake washing step is reused, at least a part of the third filtrate is recovered and stored. In the storage tank, observe any one or more of the following (1)~(5) to determine whether to reuse the aforementioned third filtrate, (1) The total time of the above-mentioned third filtrate reuse treatment (2) The total amount of water processed by the third filtrate reuse mentioned above (3) pH of the aforementioned third filtrate (4) The chloride ion concentration of the aforementioned third filtrate (5) The conductivity of the aforementioned third filtrate. The desalination treatment method for chlorine-containing powder according to any one of claims 1 to 6, wherein at least a part of the second filtrate obtained in the first desalting cake washing step is recovered and stored, and reused as a supply. The chlorine-containing powder in the later stage corresponds to the second desalting washing liquid used in the first desalting cake washing step. After being reused once or multiple times, it is recycled as the first desalting washing liquid. . For example, in the desalination treatment method for chlorine-containing powder of Claim 7, when the aforementioned second filtrate obtained in the aforementioned first desalting cake washing step is reused, in the storage tank where at least a part of the second filtrate is recovered and stored, the observation Determine whether to reuse the aforementioned second filtrate based on any one or more of the following (1)~(5), (1) The total time of the above-mentioned second filtrate reuse treatment (2) The total amount of water processed by the second filtrate reuse mentioned above (3) pH of the aforementioned second filtrate (4) The chloride ion concentration of the second filtrate mentioned above (5) The conductivity of the aforementioned second filtrate. The desalination treatment method for chlorine-containing powder according to any one of claims 1 to 8, wherein in the first desalination cake washing step, the first desalination cake is washed with the second desalination washing liquid. Use the second desalting washing liquid multiple times, and/or In the second desalting cake washing step, the washing of the second desalting cake with the third desalting washing liquid is performed a plurality of times with the third desalting washing liquid. The desalting treatment method for chlorine-containing powder according to any one of claims 1 to 9, wherein the amount of water used is 1.5 to 4 parts by mass relative to 1 part by mass of the dry weight of the chlorine-containing powder to be desalted. . The desalting treatment method for chlorine-containing powder according to any one of claims 1 to 10, wherein the aforementioned desalting cake forming step, the aforementioned first desalting cake washing step, and the aforementioned second desalting cake washing step are based on one solid-liquid process. separation device.

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