JP4121418B2 - Cement kiln combustion gas extraction dust treatment method - Google Patents

Description

【００４８】
【発明の効果】
以上説明したように、本発明にかかるセメントキルン燃焼ガス抽気ダストの処理方法によれば、塩素バイパスダストを脱塩処理する際に、固液分離後のセレンの除去に要する還元剤の量を大幅に低減し、運転コストを低く抑えること等が可能となる。
【図面の簡単な説明】
【図１】本発明にかかるセメントキルン燃焼ガス抽気ダストの処理方法を実施するためのシステムを示すフローチャートである。
【図２】図１の処理システムに用いる電気透析装置の原理を説明するための概略図である。
【図３】本発明にかかるセメントキルン燃焼ガス抽気ダストの処理方法を実施するためのシステムの一実施例を示すフローチャートである。
【図４】本発明にかかるセメントキルン燃焼ガス抽気ダストの処理方法の試験例を説明するための図であって、（ａ）は比較例、（ｂ）は実施例を示すフローチャートである。
【符号の説明】
１ セメントキルン燃焼ガス抽気ダスト処理システム
２ 溶解槽
３ 固液分離装置
４ 薬液反応槽
５ 薬液反応槽
６ 固液分離装置
７ 電気透析装置
７ａ 陽極
７ｂ 陰極
７ｃ 陽イオン交換膜
７ｄ 陰イオン交換膜
７ｅ 脱塩室
７ｆ 濃縮室
８ 循環ルート
１１ ボイラ
１２ 温水槽
１３ 溶解槽
１４ ベルトフィルタ
１５ 貯槽
１６ 薬液反応槽
１７ フィルタープレス
１８ 薬液反応槽
１９ フィルタープレス
２０ 薬液反応槽
２１ 除鉄塔
２２ キレート樹脂塔
２３ ろ過装置
２４ 電気透析装置
２５ ボイラ
２６ 加熱器
２７ 結晶装置
２８ コンデンサ
２９ ろ液タンク
３０ 遠心分離機
４１ 溶解槽
４２ ろ過装置
４３ 薬液反応槽
４４ 薬液反応槽
４５ ろ過装置
５１ 溶解槽
５２ ろ過装置
５３ 薬液反応槽
５４ 薬液反応槽
５５ ろ過装置
５６ 電気透析装置BACKGROUND OF THE INVENTION
The present invention relates to a method of treating cement kiln combustion gas extraction dust, and in particular, a part of combustion gas is extracted from a kiln exhaust gas passage from the bottom of the kiln to the bottom cyclone to remove chlorine and sulfur. The present invention also relates to a method for treating cement kiln combustion gas extraction dust that effectively uses dust contained in the extracted combustion gas.
[0001]
[Prior art]
Focusing on chlorine, sulfur, alkali, etc. that cause problems such as blockage of pre-heaters in cement production facilities, focusing on the particular problem of chlorine, from the kiln bottom of cement kilns to bottom cyclones From the kiln exhaust gas flow path, a chlorine bypass facility for extracting a part of combustion gas and removing chlorine is used.
[0002]
In this chlorine bypass facility, chlorine is unevenly distributed on the fine powder side of the dust generated by cooling the extracted combustion gas, so the dust is separated into coarse powder and fine powder by a classifier, and the coarse powder is converted into a cement kiln system. At the same time, fine powder (chlorine bypass dust) containing separated potassium chloride and the like was recovered and added to the cement grinding mill system (for example, see Patent Document 1).
[0003]
However, in recent years, recycling of waste by converting it into cement raw material or fuel has been promoted, and as the amount of waste processed increases, the amount of chlorine, sulfur, alkali and other volatile components brought into the cement kiln also increases. The amount of bypass dust is also increasing. For this reason, all of the chlorine bypass dust could not be used in the cement crushing process and was washed with water. However, the amount of chlorine bypass dust generated is expected to increase further in the future, so the development of an effective method for its use is expected. Was demanded.
[0004]
From this point of view, in the cement raw material treatment method described in Patent Document 2, chlorine bypass dust that has been conventionally washed with water is desalted and effectively used as a cement raw material. Therefore, water is added to waste containing chlorine. The chlorine in the waste is eluted and filtered, and the resulting desalted cake is used as a raw material for cement, and the wastewater is purified and discharged or recovered to recover chlorine without causing environmental pollution. We are trying to make effective use of bypass dust.
[0005]
[Patent Document 1]
International Publication No. WO97 / 21 Pamphlet [Patent Document 2]
Japanese Patent Laid-Open No. 11-100343
[Problems to be solved by the invention]
Conventionally, when desalinating chlorine bypass dust, the pH of the wastewater is adjusted with hydrochloric acid, etc., and the pH is adjusted by adding a chemical agent having iron ions having a reducing action, and after removing heavy metals such as selenium, It was necessary to discharge to sewage and the ocean. However, in order to remove the selenium concentration in the wastewater to a safe standard, for example, 0.1 mg-Se / l in the case of sewage discharge, ferrous chloride (FeCl ₂ ) as a reducing agent is 8000 mg-Fe. ^{2 +} / l or more was necessary, and there was a problem that a large amount of reducing agent was consumed in removing selenium, resulting in a high operating cost.
[0007]
Therefore, the present invention has been made in view of the above problems in the prior art, and when desalinating chlorine bypass dust, the amount of reducing agent required for removing selenium after solid-liquid separation is greatly increased. It is an object of the present invention to provide a method for treating cement kiln combustion gas bleed dust that can be reduced to a low operating cost.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a method for treating cement kiln combustion gas extraction dust, extracting a portion of cement kiln combustion gas, collecting dust contained in the extracted combustion gas, After adding water to the collected dust to form a slurry, it is separated into a primary cake and a primary filtrate containing selenium, and a ferrous compound is added to the primary filtrate containing selenium , By adjusting the pH of the primary filtrate to 8 or more and 11 or less, the selenium concentration is reduced to 0.3 mg / l or more and 5 mg / l or less, and the filtrate with the reduced selenium concentration is added to the secondary cake and selenium. The secondary filtrate containing selenium is passed through an electrodialyzer and separated into concentrated salt water and demineralized water containing selenium. Recycling as part of the water added to the dust And butterflies.
[0009]
According to the present invention, the reduction of the selenium concentration by adding the ferrous compound as a reducing agent and adjusting the pH is limited to a medium concentration range of 0.3 mg / l or more and 5 mg / l or less. In order to further reduce the selenium concentration by passing through a dialysis machine and reduce it to the final target value, when reducing the selenium concentration in the wastewater discharged out of the system as concentrated brine to a predetermined value or less, as a reducing agent The amount of ferrous compound added can be greatly reduced. In particular, the removal of selenium up to the above medium concentration range is possible with the addition of a relatively small amount of ferrous compound. Then, it is passed through an electrodialyzer and finally, for example, when the selenium concentration is discharged into sewage If the allowable reference value is 0.1 mg / l or less, the amount of ferrous compound added as a reducing agent can be greatly reduced. At this time, since the desalted water is circulated and used as part of the water added to the collected dust, no wastewater treatment is required, and the amount of chemicals required for the wastewater treatment can be greatly reduced.
[0010]
In the processing method of the cement kiln combustion gas extracted dust, the use of having a high selective permeability of monovalent ions of monovalent anion permselective membranes such as electrodialysis apparatus, the amount reducing effect of ferrous compounds higher can do.
[0011]
Further, in the method for treating cement kiln combustion gas bleed dust , a pH adjuster containing any one of calcium hydroxide, sodium hydroxide, and potassium hydroxide is added to the primary filtrate to which the ferrous compound is added. By adding, the pH of the primary filtrate can be adjusted .
[0012]
Furthermore, the salt containing either potassium chloride or sodium chloride is recoverable by evaporating the concentrated salt water. Moreover, you may discharge | release to at least any one of a sewer, a river, and the ocean, without collect | recovering salts from concentrated salt water. The primary cake or / and the secondary cake can be effectively used as a raw material for producing cement.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 shows an example of a system for carrying out a method for treating cement kiln combustion gas bleed dust according to the present invention. This treatment system 1 includes a dissolution tank 2, a solid-liquid separator 3, and a chemical reaction tank 4. 5, a solid-liquid separator 6, an electrodialyzer 7, and a circulation route 8 for returning the desalted water separated by the electrodialyzer 7 to the dissolution tank 2.
[0015]
The dissolution tank 2 is for dissolving water-soluble chlorine contained in the chlorine bypass dust in warm water, and this warm water is supplied from a boiler or the like. The dissolution tank 2 is supplied with demineralized water from the subsequent electrodialysis apparatus 7 via the circulation route 8.
[0016]
The solid-liquid separator 3 is a belt filter or the like, and separates the slurry from the dissolution tank 2 into a primary cake and a primary filtrate.
[0017]
The chemical reaction tank 4 is for adding a ferrous compound as a pH adjuster and a reducing agent to the primary filtrate from the solid-liquid separator 3. The chemical reaction tank 5 is for adding another kind of pH adjusting agent. This operation is performed to reduce the selenium concentration in the filtrate.
[0018]
The solid-liquid separator 6 is a filter press or the like, and separates the slurry from the chemical reaction tank 5 into a secondary cake and a secondary filtrate.
[0019]
The electrodialyzer 7 functions to include monovalent anions and cations in the secondary filtrate from the solid-liquid separator 6 on the concentrated salt water side. This will be described with reference to FIG.
[0020]
The electrodialysis apparatus 7 includes an anode 7a and a cathode 7b at both ends, and a cation exchange membrane 7c as an ion exchange membrane and an anion exchange membrane 7d are alternately arranged between the electrodes 7a and 7b. A desalting chamber 7e or a concentration chamber 7f is formed between the cation exchange membrane 7c and the anion exchange membrane 7d. Process liquid (solid-liquid separator 6 filtrate) is supplied to the desalting chamber 7e, K ⁺ is included in the processing liquid to move through the cation exchange membrane 7c to concentrating chamber 7f, Cl ^- is Then, it passes through the anion exchange membrane 7d and moves to the concentration chamber 7f. On the other hand, if the anion exchange membrane has selectivity for monovalent ions, selenic acid (SeO ₄ ²⁻ ) is divalent and therefore remains in the desalting chamber 7e. As a result, an anion having a valence of ² or more such as SeO ₄ ²⁻ remains in the desalting chamber 7e, and K ⁺ and Cl ⁻ move to the concentration chamber 7f, and these become KCl and are included in the concentrated salt water. , SeO ₄ ^2- is included in the demineralized water.
[0021]
The circulation route 8 is provided for returning the desalted water from the electrodialyzer 7 to the dissolution tank 2.
[0022]
Next, the operation of the processing system 1 having the above configuration will be described.
[0023]
Chlorine bypass dust is supplied to the dissolution tank 2, and water-soluble chlorine content contained in the chlorine bypass dust is dissolved in warm water. The slurry discharged from the dissolution tank 2 is solid-liquid separated by the solid-liquid separator 3, and the primary cake from which the chlorine content has been removed is returned to the cement kiln or directly added to the cement grinding mill system and used as a cement raw material. Used as On the other hand, the filtrate containing the chlorine content is supplied to the chemical reaction tank 4.
[0024]
The primary filtrate containing heavy metals such as chlorine and selenium is precipitated by reducing selenium by the ferrous compound in the chemical reaction tank 4 adjusted in pH by the pH adjuster, and in the chemical reaction tank 5. By adjusting the pH to 8 to 11 with the adjusting agent, the selenium concentration in the filtrate decreases. Here, selenium removal by a reducing agent requires a large amount of chemicals to remove to a low concentration range (0.3 mg-Se / l or less), but a medium concentration range (0.3-5 mg-Se / l). )) Can be removed with a relatively small amount. Therefore, selenium removal in the chemical reaction tank 4 is limited to the middle concentration range, and the amount of reducing agent used is reduced.
[0025]
Next, the slurry discharged from the chemical reaction tank 5 is solid-liquid separated by the solid-liquid separator 6, the secondary cake is returned to the cement kiln and used as a cement raw material, and the secondary filtrate is supplied to the electrodialyzer 7. Supply. In the electrodialysis apparatus 7, as described above, the selenic acid (SeO ₄ ²⁻ ) in the filtrate is included in the demineralized water, and the chlorine content is included in the concentrated brine.
[0026]
The demineralized water containing selenium from the electrodialyzer 7 is returned to the dissolution tank 2 via the circulation route 8 and circulated for use. On the other hand, the concentrated salt water discharged from the electrodialyzer 7 can be discharged or the industrial salt can be recovered by a salt recovery facility and used as an industrial raw material. As a result, selenium is removed in the chemical reaction tank 4 to a medium concentration range (0.3-5 mg-Se / l), and selenium is removed to a low concentration range (0.3 mg-Se / l or less) by the electrodialyzer 7. Therefore, the amount of reducing agent used can be greatly reduced as compared with the conventional case.
[0027]
Next, an embodiment of a method for treating cement kiln combustion gas extraction dust according to the present invention will be described with reference to FIG.
[0028]
As shown in the figure, the cement kiln combustion gas extraction dust treatment method is roughly divided into a water washing step, a waste water treatment step, and a salt recovery step.
[0029]
The water washing step is a step of washing the chlorine bypass dust with water to remove the chlorine content. In order to carry out this step, the boiler 11, the hot water tank 12, the dissolution tank 13, the belt filter 14, and the storage tank are used. 15 are provided.
[0030]
Hot water generated in the boiler 11 is supplied to the dissolution tank 13 through the hot water tank 12 and mixed with chlorine bypass dust. In the dissolution tank 13, the water-soluble chlorine content contained in the chlorine bypass dust is dissolved in warm water. The slurry discharged from the dissolution tank 13 is solid-liquid separated in the belt filter 14, and the primary cake from which the chlorine content has been removed is returned to the cement kiln and used as a cement raw material. On the other hand, the primary filtrate containing chlorine and heavy metals such as selenium is temporarily stored in the storage tank 15.
[0031]
The wastewater treatment step is a step of removing heavy metals such as selenium and calcium from the primary filtrate, and in order to carry out this step, the chemical reaction tanks 16, 18, 20 and a filter as a solid-liquid separation device Presses 17 and 19, iron removal tower 21, chelate resin tower 22, filtration device 23, and electrodialysis device 24 are provided.
[0032]
The primary filtrate containing chlorine, heavy metals such as selenium, and calcium stored in the storage tank 15 is supplied to the chemical reaction tank 16. Hydrochloric acid as a pH adjusting agent is added to the chemical reaction tank 16 to adjust the pH in the chemical reaction tank 16 to 4 or less. The reason for supplying hydrochloric acid is to dissolve ferrous sulfate as a reducing agent to enhance the effect as a reducing agent.
[0033]
With ferrous sulfate, selenium as a heavy metal contained in the waste water is reduced and deposited. Here, in order to suppress the addition amount of ferrous sulfate as a reducing agent, the selenium concentration of the secondary filtrate is set to about 0.8 mg-Se / l. Next, calcium hydroxide is added to raise the pH to 8 to 11, and the ferrous hydroxide produced by the addition of ferrous sulfate is condensed and precipitated. The reason why the pH is adjusted to 8 to 11 is that ferrous hydroxide and a selenium compound and / or selenium metal precipitate as products in such a pH range. In place of calcium hydroxide, sodium hydroxide, potassium hydroxide or the like may be used.
[0034]
And the slurry discharged | emitted from the chemical | medical solution reaction tank 16 is solid-liquid separated by the filter press 17, and a secondary cake is returned to a cement kiln etc. and used as a cement raw material, and a secondary filtrate is potassium carbonate in the chemical | medical solution reaction tank 18. And calcium in the secondary filtrate is removed. The reason why calcium in the secondary filtrate is removed is to prevent clogging between the exchange membranes due to the calcium scale in the electrodialysis apparatus 24 in the subsequent stage. In addition, you may use sodium carbonate instead of potassium carbonate.
[0035]
Next, the slurry discharged from the chemical reaction tank 18 is separated into solid and liquid by a filter press 19, and the tertiary cake is returned to the cement kiln and used as a cement raw material. The pH of the tertiary filtrate is adjusted by adding hydrochloric acid. After that, iron, residual heavy metals, and suspended substances (SS) are removed by the iron removal tower 21, the chelate resin tower 22, and the filtration device 23.
[0036]
The waste water from the filtration device 23 is supplied to the electrodialysis device 24, and in the electrodialysis device 24, selenic acid (SeO ₄ ²⁻ ) in the waste water is included in the desalted water, and the chlorine content is included in the concentrated salt water. The desalinated water from the electrodialyzer 24 is returned to the hot water tank 12 in the water washing step via a circulation route (not shown) (see reference A). Thereby, the selenium concentration of concentrated salt water is reduced to 0.1 mg-Se / l or less which is an allowable value in the case of sewage discharge, for example.
[0037]
The salt recovery step is a step of recovering the salt from the concentrated salt water to obtain industrial raw materials. In order to carry out this step, the boiler 25, the heater 26, the crystal device 27, the capacitor 28, and the filtrate tank 29 and a centrifuge 30 are provided.
[0038]
The concentrated salt water is heated in the heater 26 by the steam from the boiler 25, and crystallization is performed in the crystallizer 27. In the crystallizer 27, the solute in the concentrated salt water is precipitated as crystals, and the industrial salt is recovered through the centrifuge 30 and used as an industrial raw material. On the other hand, the water evaporated in the crystal device 27 is cooled in the condenser 28 to recover the drain, and this drain is returned to the water washing step. The filtrate separated by the centrifuge 30 is returned to the crystal device 27 through the filtrate tank 29. In addition, it is also possible to discharge the salt without recovering the salt from the concentrated salt water.
[0039]
Next, a test example of a method for treating cement kiln combustion gas extraction dust according to the present invention will be described with reference to FIG.
[0040]
FIG. 4A is a flowchart showing a comparative example, and shows a case where selenium removal is performed without using an electrodialyzer, and FIG. 4B shows an embodiment of the present invention using an electrodialyzer. It is a flowchart to show.
[0041]
In the comparative example of FIG. 4A, the chlorine bypass dust is supplied to the dissolution tank 41, and the water-soluble chlorine content contained in the chlorine bypass dust is dissolved in water. The slurry discharged from the dissolution tank 41 is solid-liquid separated by the filtration device 42 and separated into a primary cake and a primary filtrate. The selenium concentration of this primary filtrate was 32 mg-Se / l.
[0042]
The primary filtrate containing chlorine and selenium is supplied to the chemical reaction tank 43, and after adding the ferrous compound in the chemical reaction tank 43 whose pH is adjusted by the pH adjuster, the pH is adjusted in the chemical reaction tank 44. By adjusting the pH to 8 to 11 with the adjusting agent, selenium is reduced and deposited. And the slurry from the chemical | medical solution reaction tank 44 is solid-liquid separated by the filtration apparatus 45, and is isolate | separated into a secondary cake and a secondary filtrate. Here, when the selenium concentration of the secondary filtrate is 0.1 mg-Se / l, which is an acceptable standard for sewage discharge, the amount of ferrous compound used as the reducing agent is 8000 mg Fe ²⁺ / l or more. there were.
[0043]
On the other hand, in the embodiment of FIG. 4B, the chlorine bypass dust is supplied to the dissolution tank 51, and the water-soluble chlorine content contained in the chlorine bypass dust is dissolved in water. The slurry discharged from the dissolution tank 51 is separated into a solid and a liquid by a filtration device 52 and separated into a primary cake and a primary filtrate. The selenium concentration in the primary filtrate was 32.8 mg-Se / l because demineralized water containing selenium in the electrodialyzer 55 was returned to the dissolution tank 51 as described later.
[0044]
The primary filtrate containing chlorine and selenium is supplied to the chemical reaction tank 53, and after adding the ferrous compound in the chemical reaction tank 53 whose pH is adjusted by the pH adjuster, the pH is adjusted in the chemical reaction tank 54. By adjusting the pH to 8 to 11 with the adjusting agent, selenium is reduced and deposited. And the slurry from the chemical | medical solution reaction tank 54 is solid-liquid separated by the filtration apparatus 55, and isolate | separated into a secondary cake and a secondary filtrate. Thereafter, the secondary filtrate is separated into concentrated salt water and demineralized water containing selenium by the electrodialyzer 56, and the demineralized water containing selenium is returned to the dissolution tank 51 and circulated.
[0045]
Here, when the selenium concentration is set to 0.1 mg-Se / l, which is an acceptable standard in the case of sewage discharge, the selenium concentration in the secondary filtrate is reduced to 0.8 mg-Se / l by removing selenium in the chemical reaction tank 53. Then, most of the selenium in the secondary filtrate is moved to the desalted water side by the electrodialyzer 56 using a monovalent anion selective membrane, and the acceptable standard in the case of sewage discharge is 0.1 mg- Se / l. As described above, the removal of selenium up to the middle concentration range (0.3-5 mg-Se / l) requires only the addition of a relatively small amount of ferrous compound, and this time the selenium concentration in the secondary filtrate is reduced to 0. the addition amount of the ferrous compound agent to reduce to 8 mg-Se / l was about 2,000 mg-Fe ²⁺ / l.
[0046]
As described above, when the selenium concentration is made 0.1 mg-Se / l or less, which is an acceptable standard in the case of sewage discharge, the amount of ferrous compound added in the comparative example and the example is as shown in Table 1. Thus, it can be seen that the present invention can greatly reduce the amount of reducing agent.
[0047]
[Table 1]

[0048]
【The invention's effect】
As described above, according to the cement kiln combustion gas extraction dust processing method according to the present invention, when desalinating chlorine bypass dust, the amount of reducing agent required for removing selenium after solid-liquid separation is greatly increased. It is possible to reduce the operation cost and the like.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a system for carrying out a method for treating cement kiln combustion gas bleed dust according to the present invention.
FIG. 2 is a schematic diagram for explaining the principle of an electrodialysis apparatus used in the treatment system of FIG.
FIG. 3 is a flowchart showing an embodiment of a system for carrying out a method for treating cement kiln combustion gas bleed dust according to the present invention.
FIGS. 4A and 4B are diagrams for explaining a test example of a method for treating cement kiln combustion gas bleed dust according to the present invention, in which FIG. 4A is a flowchart showing a comparative example, and FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cement kiln combustion gas extraction dust processing system 2 Dissolution tank 3 Solid-liquid separator 4 Chemical reaction tank 5 Chemical reaction tank 6 Solid-liquid separator 7 Electrodialyzer 7a Anode 7b Cathode 7c Cation exchange membrane 7d Anion exchange membrane 7e Desorption Salt chamber 7f Concentration chamber 8 Circulation route 11 Boiler 12 Hot water tank 13 Dissolution tank 14 Belt filter 15 Storage tank 16 Chemical liquid reaction tank 17 Filter press 18 Chemical liquid reaction tank 19 Filter press 20 Chemical liquid reaction tank 21 Iron removal tower 22 Chelate resin tower 23 Filtration device 24 Electrodialyzer 25 Boiler 26 Heater 27 Crystallizer 28 Condenser 29 Filtrate tank 30 Centrifugal machine 41 Dissolution tank 42 Filtration apparatus 43 Chemical liquid reaction tank 44 Chemical liquid reaction tank 45 Filtration apparatus 51 Dissolution tank 52 Filtration apparatus 53 Chemical liquid reaction tank 54 Chemical liquid Reaction tank 55 Filtration device 56 Electrodialysis device

Claims (6)

Extract a part of the cement kiln combustion gas, collect the dust contained in the extracted combustion gas,
After adding water to the collected dust to form a slurry, it is separated into a primary cake and a primary filtrate containing selenium,
While adding a ferrous compound to the primary filtrate containing selenium , and adjusting the pH of the primary filtrate to 8 or more and 11 or less, the selenium concentration is 0.3 mg / l or more and 5 mg / l. Reduced to
Separating the filtrate with reduced selenium concentration into a secondary cake and a secondary filtrate containing selenium;
The secondary filtrate containing the selenium is passed through an electrodialyzer and separated into concentrated brine and demineralized water containing selenium,
A method for treating cement kiln combustion gas extraction dust, wherein the demineralized water containing selenium is circulated and used as a part of water added to the collected dust.   The method for treating cement kiln combustion gas extraction dust according to claim 1, wherein the electrodialyzer uses a monovalent anion selective permeable membrane to separate concentrated salt water into demineralized water containing selenium. The pH of the primary filtrate is adjusted by adding a pH adjuster containing any one of calcium hydroxide, sodium hydroxide, and potassium hydroxide to the primary filtrate to which the ferrous compound is added. method of processing cement kiln combustion gas extracted dust according to claim 1 or 2, characterized in that. The method for treating cement kiln combustion gas bleed dust according to claim 1, 2 or 3 , wherein the concentrated salt water is evaporated to recover a salt containing at least one of potassium chloride and sodium chloride. The concentrated salt water, sewage, river, method of processing cement kiln combustion gas extracted dust according to any one of claims 1 to 4, characterized in that the discharge in at least one of the ocean. Method of processing cement kiln combustion gas extracted dust according to any one of claims 1 to 5, characterized in that the primary cake or / and the second cake utilizes a raw material for cement production.

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