JP5028741B2

JP5028741B2 - Dust disposal method

Info

Publication number: JP5028741B2
Application number: JP2005025881A
Authority: JP
Inventors: 正治石渡; 泰成天海; 英樹村松; 春樹三浦
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2004-02-18
Filing date: 2005-02-02
Publication date: 2012-09-19
Anticipated expiration: 2025-02-02
Also published as: JP2005262205A

Description

本発明は、セメントキルンから塩素、アルカリ等をバイパスさせて得られたキルンダスト、或いは焼却炉、溶融炉、ガス化溶融炉等から得られた飛灰、溶融飛灰、ダスト等の処理方法に関する。更に詳しくは重金属、塩素、アルカリ等を含有する飛灰、ダストからの有価金属、含有塩化物、肥料原料、化学原料、製錬原料、セメント原料等の再資源化のためのダスト処理方法に関するものである。更に本発明は、ダスト等からの肥料原料又は化学原料の製造方法並びに製錬原料又はセメント原料の製造方法に関するものである。 The present invention relates to a method for treating kiln dust obtained by bypassing chlorine, alkali or the like from a cement kiln, or fly ash obtained from an incinerator, melting furnace, gasification melting furnace or the like, molten fly ash, dust or the like. More specifically, it relates to a dust treatment method for recycling heavy metals, chlorine, alkali and other fly ash, valuable metals from dust, contained chlorides, fertilizer raw materials, chemical raw materials, smelting raw materials, cement raw materials, etc. It is. Furthermore, this invention relates to the manufacturing method of the fertilizer raw material or chemical raw material from dust etc., and the manufacturing method of a smelting raw material or a cement raw material.

従来、この種のダスト処理方法として、キルン熱処理ガスのダストに水に代表されるｐＨ調整剤を添加することにより、このダスト中の第１障害物質の沈殿に最適なｐＨの１次スラリーに調製する工程と、この１次スラリー中で沈殿した第１障害物質を除去する工程と、この１次スラリーにキルン排ガスに代表されるｐＨ調整剤を添加し、第２障害物質の沈殿に最適なｐＨの２次スラリーにする工程とを備えたキルンダストの処理システムが開示されている（例えば、特許文献１参照。）。 Conventionally, as a dust treatment method of this type, a pH-adjusting agent represented by water is added to the dust of the kiln heat treatment gas to prepare a primary slurry having a pH optimum for precipitation of the first obstacle substance in the dust. And a step of removing the first obstacle substance precipitated in the primary slurry, and a pH adjusting agent represented by kiln exhaust gas is added to the primary slurry, so that a pH optimum for the precipitation of the second obstacle substance is obtained. The kiln dust processing system including the process of making the secondary slurry is disclosed (for example, see Patent Document 1).

また別のダスト処理方法として、可溶性重金属塩とＮａＣｌ、ＫＣｌ、Ｎａ₂ＳＯ₄、Ｋ₂ＳＯ₄等のアルカリ金属塩を含む微粉状廃棄物または微粉状にした廃棄物を水に浸漬し、この廃棄物中に含まれる可溶性重金属塩及びアルカリ金属塩を水に溶解するとともに、ＮａＯＨ、Ｃａ(ＯＨ)₂等のアルカリを添加し、このアルカリによって可溶性重金属塩を不溶性の重金属水酸化物とし、次いでこれをろ過し、ろ液中に上記アルカリ金属塩を移行せしめることにより、このアルカリ金属塩を分離したろ過残渣を作成し、このろ過残渣を高温焼結または高温溶融処理する微粉状廃棄物の処理方法が開示されている（例えば、特許文献２参照。）。
特許第２７６４５０８号公報（請求項１、［００１１］、図１）特公昭６３−５８６３８号公報（特許請求の範囲、図１） As another dust treatment method, a pulverized waste or a pulverized waste containing a soluble heavy metal salt and an alkali metal salt such as NaCl, KCl, Na ₂ SO ₄ or K ₂ SO ₄ is immersed in water. The soluble heavy metal salt and alkali metal salt contained in the waste are dissolved in water, and an alkali such as NaOH and Ca (OH) ₂ is added to convert the soluble heavy metal salt into an insoluble heavy metal hydroxide by this alkali. By filtering this and transferring the alkali metal salt into the filtrate, a filtration residue is prepared by separating the alkali metal salt, and the filtration residue is subjected to high-temperature sintering or high-temperature melting treatment. A method is disclosed (for example, refer to Patent Document 2).
Japanese Patent No. 2764508 (Claim 1, [0011], FIG. 1) Japanese Patent Publication No. 63-58638 (Claims, FIG. 1)

特許文献１の処理方法では、ｐＨ調整を二段階で行いかつ第１障害物質を除去する必要があり、工程が煩雑になるとともに、水酸化物の最小溶解度までしか重金属を除去できず、結果としてろ液中の重金属濃度を低減することが困難である。
一方、特許文献２の処理方法では、ダストを水に浸漬して得られたスラリーにＮａＯＨ、Ｃａ(ＯＨ)₂等のアルカリを添加することによって可溶性重金属塩を不溶性の重金属水酸化物としているけれども、重金属水酸化物はその種類毎に溶解度が異なるため、上記アルカリによって水酸化物を生成させる処理では、複数の重金属を低濃度まで除去し難く、結果としてろ液中の重金属濃度を低減することができない。
本発明の目的は、固液分離した後の液中の重金属濃度を効率的に低減することができるダスト処理方法を提供することにある。 In the treatment method of Patent Document 1, it is necessary to adjust the pH in two steps and remove the first obstacle substance, and the process becomes complicated, and heavy metal can be removed only to the minimum solubility of hydroxide, and as a result It is difficult to reduce the heavy metal concentration in the filtrate.
On the other hand, in the treatment method of Patent Document 2, soluble heavy metal salt is made into insoluble heavy metal hydroxide by adding alkali such as NaOH, Ca (OH) ₂ to slurry obtained by immersing dust in water. Since the solubility of heavy metal hydroxides varies depending on the type, it is difficult to remove a plurality of heavy metals to a low concentration in the above-described treatment of generating hydroxides with alkali, and as a result, the concentration of heavy metals in the filtrate is reduced. I can't.
An object of the present invention is to provide a dust treatment method capable of efficiently reducing the heavy metal concentration in the liquid after the solid-liquid separation.

請求項１に係る発明は、図１の実線で示すように、カルシウム含有量が５重量％以上であってＣｄ、Ｐｂ、Ｚｎ及びＣｕの重金属を少なくとも含むダスト１０と水１３とを混合してｐＨ１２以上のスラリーを調製するとともに、ｐＨ値を１２以上としたスラリー中でＣｄ及びＣｕの殆どを水に不溶性の水酸化物にする工程１４と、このｐＨ値を１２以上としたスラリーに炭酸ガス１６を吹き込み、スラリーのｐＨをスラリー調製時のｐＨ値より低い１０〜１１．５の範囲にまで低下させてスラリーに溶解しているＰｂ、Ｚｎの水に対する溶解度を低下させ、水酸化物又は炭酸塩の形態で沈殿させ、かつ、僅かに溶存するＣｄを炭酸塩の形態で沈殿させる工程１７と、この炭酸ガスを吹き込んだスラリーを３０分以上１２時間以下の範囲内で静置して、スラリーに溶解して残留している重金属をカルシウム塩との共沈効果により沈澱させ、スラリーに溶解している重金属濃度をより一層低減する第１次静置工程１８ａと、この第１次静置工程の静置物を固液分離する第１次固液分離工程１９ａと、この第１次固液分離により得られた第１次ろ液２１ａを３０分以上１２時間以下の範囲内で静置して、第１次ろ液に溶解して残留している重金属を第１次ろ液に溶解していた過飽和のカルシウム塩との共沈効果により更に沈澱させ、第１次ろ液に溶解している重金属濃度を更に低減する第２次静置工程１８ｂと、この第２次静置工程の静置物を固液分離する第２次固液分離工程１９ｂとを含むダスト処理方法である。 As shown by the solid line in FIG. 1, the invention according to claim 1 is a mixture of dust 10 and water 13 having a calcium content of 5% by weight or more and containing at least heavy metals of Cd, Pb, Zn and Cu. A slurry having a pH of 12 or more is prepared, and in the slurry having a pH value of 12 or more , most of Cd and Cu are converted to water-insoluble hydroxides, and carbon dioxide gas is added to the slurry having a pH value of 12 or more. 16 is blown, and the pH of the slurry is lowered to a range of 10 to 11.5 lower than the pH value at the time of slurry preparation, so that the solubility of Pb and Zn dissolved in the slurry is reduced. The step 17 for precipitating in the form of a salt and precipitating slightly dissolved Cd in the form of a carbonate and the slurry into which the carbon dioxide gas has been blown are allowed to stand for 30 minutes to 12 hours. A first stationary step 18a for further reducing the concentration of heavy metal dissolved in the slurry by precipitating the heavy metal remaining in the slurry by coprecipitation with the calcium salt. The primary solid-liquid separation step 19a for solid-liquid separation of the stationary product in the primary stationary step and the primary filtrate 21a obtained by the primary solid-liquid separation within a range of 30 minutes to 12 hours. Left to stand for further precipitation of the heavy metal remaining in the primary filtrate by the coprecipitation effect with the supersaturated calcium salt dissolved in the primary filtrate. A dust treatment method including a second stationary step 18b for further reducing the concentration of heavy metals dissolved in the solid, and a second solid-liquid separation step 19b for solid-liquid separation of the stationary substance in the second stationary step. is there.

請求項２に係る発明は、請求項１に係る発明であって、第２次固液分離により得られた第２次ろ液２１ｂを蒸発・晶析する工程２２と、この蒸発・晶析により得られた固形物２３から肥料原料又は化学原料を生成する工程とを更に含む処理方法である。
請求項３に係る発明は、請求項１に係る発明であって、第１次又は第２次固液分離のいずれか又は双方により得られた残渣２４ａ，２４ｂから製錬原料又はセメント原料を生成する工程を更に含む処理方法である。 The invention according to claim 2 is the invention according to claim 1, wherein a step 22 of evaporating and crystallizing the secondary filtrate 21b obtained by the secondary solid-liquid separation, and the evaporation and crystallization are performed. And a step of generating a fertilizer raw material or a chemical raw material from the obtained solid material 23.
The invention according to claim 3 is the invention according to claim 1, wherein a smelting raw material or a cement raw material is generated from the residues 24a and 24b obtained by either or both of the primary and secondary solid-liquid separations. It is the processing method which further includes the process to do.

請求項４に係る発明は、図１の実線で示すように、カルシウム含有量が５重量％以上であってＣｄ、Ｐｂ、Ｚｎ及びＣｕの重金属を少なくとも含むダスト１０と水１３とを混合してｐＨ１２以上のスラリーを調製するとともに、ｐＨ値を１２以上としたスラリー中でＣｄ及びＣｕの殆どを水に不溶性の水酸化物にする工程１４と、このｐＨ値を１２以上としたスラリーに炭酸ガス１６を吹き込み、スラリーのｐＨをスラリー調製時のｐＨ値より低い１０〜１１．５の範囲にまで低下させてスラリーに溶解しているＰｂ、Ｚｎの水に対する溶解度を低下させ、水酸化物又は炭酸塩の形態で沈殿させ、かつ、僅かに溶存するＣｄを炭酸塩の形態で沈殿させる工程１７と、この炭酸ガスを吹き込んだスラリーを３０分以上１２時間以下の範囲内で静置して、スラリーに溶解して残留している重金属をカルシウム塩との共沈効果により沈澱させ、スラリーに溶解している重金属濃度をより一層低減する第１次静置工程１８ａと、この第１次静置工程の静置物を固液分離する第１次固液分離工程１９ａと、この第１次固液分離により得られた第１次ろ液２１ａを３０分以上１２時間以下の範囲内で静置して、第１次ろ液に溶解して残留している重金属を第１次ろ液に溶解していた過飽和のカルシウム塩との共沈効果により更に沈澱させ、第１次ろ液に溶解している重金属濃度を更に低減する第２次静置工程１８ｂと、この第２次静置工程の静置物を固液分離する第２次固液分離工程１９ｂと、この第２次固液分離１９ｂにより得られた第２次ろ液２１ｂを蒸発・晶析する工程２２と、この蒸発・晶析により得られた固形物２３から肥料原料又は化学原料を生成する工程とを含む肥料原料又は化学原料の製造方法である。 As shown by the solid line in FIG. 1, the invention according to claim 4 is a mixture of dust 13 and water 13 having a calcium content of 5% by weight or more and containing at least heavy metals of Cd, Pb, Zn and Cu. A slurry having a pH of 12 or more is prepared, and in the slurry having a pH value of 12 or more , most of Cd and Cu are converted to water-insoluble hydroxides, and carbon dioxide gas is added to the slurry having a pH value of 12 or more. 16 is blown, and the pH of the slurry is lowered to a range of 10 to 11.5 lower than the pH value at the time of slurry preparation, so that the solubility of Pb and Zn dissolved in the slurry is reduced. The step 17 for precipitating in the form of a salt and precipitating slightly dissolved Cd in the form of a carbonate and the slurry into which the carbon dioxide gas has been blown are allowed to stand for 30 minutes to 12 hours. A first stationary step 18a for further reducing the concentration of heavy metal dissolved in the slurry by precipitating the heavy metal remaining in the slurry by coprecipitation with the calcium salt. The primary solid-liquid separation step 19a for solid-liquid separation of the stationary product in the primary stationary step and the primary filtrate 21a obtained by the primary solid-liquid separation within a range of 30 minutes to 12 hours. Left to stand for further precipitation of the heavy metal remaining in the primary filtrate by the coprecipitation effect with the supersaturated calcium salt dissolved in the primary filtrate. A second stationary step 18b for further reducing the concentration of the heavy metal dissolved in the second solid solid-liquid separation step 19b for solid-liquid separation of the stationary product in the second stationary step, A step 22 of evaporating and crystallizing the secondary filtrate 21b obtained by the liquid separation 19b; A method for producing a fertilizer material or chemical raw materials and a step of generating a fertilizer material or chemical raw materials from the solids 23 obtained by crystallization.

請求項５に係る発明は、カルシウム含有量が５重量％以上であってＣｄ、Ｐｂ、Ｚｎ及びＣｕの重金属を少なくとも含むダスト１０と水１３とを混合してｐＨ１２以上のスラリーを調製するとともに、ｐＨ値を１２以上としたスラリー中でＣｄ及びＣｕの殆どを水に不溶性の水酸化物にする工程１４と、このｐＨ値を１２以上としたスラリーに炭酸ガス１６を吹き込み、スラリーのｐＨをスラリー調製時のｐＨ値より低い１０〜１１．５の範囲にまで低下させてスラリーに溶解しているＰｂ、Ｚｎの水に対する溶解度を低下させ、水酸化物又は炭酸塩の形態で沈殿させ、かつ、僅かに溶存するＣｄを炭酸塩の形態で沈殿させる工程１７と、この炭酸ガスを吹き込んだスラリーを３０分以上１２時間以下の範囲内で静置して、スラリーに溶解して残留している重金属をカルシウム塩との共沈効果により沈澱させ、スラリーに溶解している重金属濃度をより一層低減する第１次静置工程１８ａと、この第１次静置工程の静置物を固液分離する第１次固液分離工程１９ａと、この第１次固液分離により得られた第１次ろ液２１ａを３０分以上１２時間以下の範囲内で静置して、第１次ろ液に溶解して残留している重金属を第１次ろ液に溶解していた過飽和のカルシウム塩との共沈効果により更に沈澱させ、第１次ろ液に溶解している重金属濃度を更に低減する第２次静置工程１８ｂと、この第２次静置工程の静置物を固液分離する第２次固液分離工程１９ｂと、この第１次又は第２次固液分離のいずれか又は双方により得られた残渣２４ａ，２４ｂから製錬原料又はセメント原料を生成する工程とを含む製錬原料又はセメント原料の製造方法である。 The invention according to claim 5 is to prepare a slurry having a pH of 12 or more by mixing the dust 10 having a calcium content of 5% by weight or more and containing at least heavy metals such as Cd, Pb, Zn and Cu with water 13. most of Cd and Cu in a slurry with a pH value of 12 or more and the step 14 of the insoluble hydroxide in water is blown with carbon dioxide 16 the pH value in the slurry 12 or slurry the pH of the slurry is lowered to a range of less than pH values 10 to 11.5 at the time of preparation and Pb dissolved in the slurry, reduce the water solubility of the Zn, precipitated in the form of hydroxide or carbonate, and, The step 17 for precipitating slightly dissolved Cd in the form of carbonate and the slurry into which the carbon dioxide gas has been blown are allowed to stand for 30 minutes to 12 hours to dissolve in the slurry. First standing step 18a for precipitating heavy metal remaining due to coprecipitation with calcium salt and further reducing the concentration of heavy metal dissolved in the slurry, and a stationary product of this first standing step The first solid-liquid separation step 19a for solid-liquid separation and the first filtrate 21a obtained by the first solid-liquid separation are allowed to stand within a range of 30 minutes to 12 hours, The heavy metal remaining in the primary filtrate is further precipitated by the coprecipitation effect with the supersaturated calcium salt dissolved in the primary filtrate, and the concentration of heavy metal dissolved in the primary filtrate is reduced. Further reduction of the second stationary step 18b, the second solid-liquid separation step 19b for solid-liquid separation of the stationary product in the second stationary step, and either the first or second solid-liquid separation Smelting raw materials or cement raw materials are produced from the residues 24a and 24b obtained by the two or both It is a manufacturing method for smelting raw or cement material and the step.

本発明の処理方法では、次の効果を奏する。
(1) ダストと水の混合により調製されたスラリーに炭酸ガスを吹き込んで所望のｐＨ値に調整することにより、ダストに含まれていた重金属を水酸化物又は炭酸塩の形態で沈殿させることができる。
(2) 炭酸ガスを吹き込んだスラリーを静置することにより、水に溶解して残留していた重金属がカルシウム塩の沈殿に伴われて一緒に沈殿する。この静置を固液分離した後のろ液に対しても行うことにより、特許文献１及び２の処理方法と比較して、液中の重金属濃度をより効率的にかつより一層低減することができる。
(3) 固液分離した液を蒸発・晶析することにより得られた固形物には、カリウム及び塩素等のハロゲン類が多量に含まれるので、これらを肥料の原料、又は化学原料に利用することができる。
(4) 固液分離により得られた残渣は若干重金属を含むものの大部分がカルシウム化合物、シリカから構成されているので、この残渣は製錬原料又はセメント原料に利用することができる。 The processing method of the present invention has the following effects.
(1) Carbon dioxide is blown into a slurry prepared by mixing dust and water to adjust to a desired pH value, thereby precipitating heavy metals contained in the dust in the form of hydroxide or carbonate. it can.
(2) By leaving the slurry into which carbon dioxide gas has been blown, the heavy metal remaining in the water is precipitated together with the precipitation of the calcium salt. By performing this standing also on the filtrate after solid-liquid separation, the heavy metal concentration in the liquid can be more efficiently and further reduced as compared with the processing methods of Patent Documents 1 and 2. it can.
(3) Since solids obtained by evaporating and crystallizing the liquid separated into solid and liquid contain a large amount of halogens such as potassium and chlorine, these are used as fertilizer raw materials or chemical raw materials. be able to.
(4) Although the residue obtained by solid-liquid separation contains a little heavy metal, most of it is composed of calcium compound and silica, so this residue can be used for smelting raw material or cement raw material.

本発明の実施の形態を実線で示された図１に基づいて説明する。
本発明処理方法の対象となるダストは、カルシウム含有量（ＣａＯ）が５重量％以上の重金属を含むダスト１０である。カルシウム含有量が５重量％以上のダストは、水と混合してスラリーにしたときに、スラリーがアルカリ性（ｐＨ１２以上）になる。このダストを例示すれば、セメントキルンから塩素、アルカリ等をバイパスさせて得られたキルンダスト、或いは焼却炉、溶融炉、ガス化溶融炉等から得られた飛灰、溶融飛灰、ダスト等、或いは都市ごみ、廃水処理工程からでるスラッジ等を焼却処理した際に排出されるダストである。ダストに含まれる重金属には、Ｃｄ、Ｐｂ、Ｚｎ、Ｃｕ等が例示される。 An embodiment of the present invention will be described with reference to FIG. 1 indicated by a solid line.
The dust that is the subject of the treatment method of the present invention is the dust 10 containing heavy metal having a calcium content (CaO) of 5% by weight or more. Dust having a calcium content of 5% by weight or more becomes alkaline (pH 12 or more) when the slurry is mixed with water to form a slurry. To illustrate this dust, kiln dust obtained by bypassing chlorine, alkali, etc. from a cement kiln, or fly ash obtained from an incinerator, melting furnace, gasification melting furnace, etc., molten fly ash, dust, etc. It is dust discharged when incineration of municipal waste and sludge from wastewater treatment process. Examples of heavy metals contained in the dust include Cd, Pb, Zn, and Cu.

先ずダスト１０と水１３とを混合してｐＨ１２以上のスラリーを調製する（工程１４）。具体的には重量比でダストの２〜２０倍量、好ましくは３〜１０倍量の水と混合する。ｐＨ１２以上のスラリーでは、ダストに含まれる重金属のうち、Ｃｄ、Ｃｕ等はそのほとんどが水酸化物になる。この水酸化物は水に対する溶解度が非常に小さく沈殿する。ダストに含まれる重金属のうち、Ｐｂ、Ｚｎ等については、ｐＨ１２以上では水に対する溶解度が高くなり、一部がアルカリ水溶液に溶解している。 First, dust 10 and water 13 are mixed to prepare a slurry having a pH of 12 or more (step 14). Specifically, it is mixed with 2 to 20 times, preferably 3 to 10 times, the amount of dust by weight. In a slurry having a pH of 12 or more, among heavy metals contained in dust, most of Cd, Cu and the like become hydroxides. This hydroxide precipitates with very low solubility in water. Among heavy metals contained in dust, Pb, Zn, and the like have high solubility in water at pH 12 or higher, and some are dissolved in an alkaline aqueous solution.

次にこのスラリーに炭酸ガス１６を吹き込み、スラリーのｐＨをスラリー調製時のｐＨ値より低下させる。好ましくはｐＨを１２未満、更に好ましくは１０〜１１．５の範囲に低下させる（工程１７）。この炭酸ガスは、キルン、焼却炉、溶融炉等の炭酸ガスを含む排ガスでもよい。炭酸ガスの吹き込みの際に、水に不溶性の重金属水酸化物は、分散していても、或いは沈降して沈澱物であってもよい。特許文献１に記載されているようにこの不溶性の重金属水酸化物を除去する必要はない。この炭酸ガスの吹き込みとスラリーのｐＨを低下させることにより、溶解していたＰｂ、Ｚｎ等は、水に対する溶解度が低下するため、水酸化物になるとともに、炭酸塩を生成する。また僅かに溶存するＣｄ等も炭酸塩になる。この水に不溶性の重金属の水酸化物、炭酸塩は時間の経過とともに沈殿する。 Next, carbon dioxide gas 16 is blown into this slurry, and the pH of the slurry is lowered from the pH value at the time of slurry preparation. Preferably, the pH is lowered to less than 12, more preferably 10 to 11.5 (step 17). The carbon dioxide gas may be exhaust gas containing carbon dioxide gas such as kiln, incinerator, melting furnace or the like. When carbon dioxide gas is blown in, the heavy metal hydroxide that is insoluble in water may be dispersed or may be precipitated and precipitated. As described in Patent Document 1, it is not necessary to remove this insoluble heavy metal hydroxide. By blowing this carbon dioxide gas and lowering the pH of the slurry, the dissolved Pb, Zn, etc. are reduced in water solubility, and thus become hydroxides and produce carbonates. In addition, slightly dissolved Cd and the like also become carbonate. This water-insoluble heavy metal hydroxide and carbonate precipitates over time.

続いて上記スラリーを第１次静置する（工程１８ａ）。静置は３０分以上、好ましくは１〜１２時間行う。除去効率を考慮すれば１時間以上静置すれば十分であるが、装置、操業上の観点から上記範囲内から静置時間が決められる。上記上限値を越えて静置しても除去効率はそれ程向上しない。この第１次静置により、水に溶解して残留していた重金属がカルシウム塩の沈殿に伴われて一緒に沈殿する。この共沈効果により水に溶解している重金属の濃度がより一層低減する。
続いて液と沈殿物を含む第１次静置物を遠心分離、フィルタプレス等により第１次固液分離する（工程１９ａ）。この第１次固液分離により第１次ろ液２１ａと第１次残渣２４ａが得られる。第１次ろ液２１ａを更に第２次静置する（工程１８ｂ）。この静置も３０分以上、好ましくは１〜１２時間行う。除去効率を考慮すれば１時間以上静置すれば十分であるが、装置、操業上の観点から上記範囲内から静置時間が決められる。上記上限値を越えて静置しても除去効率はそれ程向上しない。この第２次静置により、溶解していた過飽和のカルシウム塩が析出するが、その際にも第１次ろ液に溶解して残留していた重金属がカルシウム塩の沈殿に伴われて一緒に沈殿する。この共沈効果により第１次ろ液に溶解している重金属の濃度が更に低減する。 Subsequently, the slurry is allowed to stand for the first time (step 18a). The standing is performed for 30 minutes or more, preferably 1 to 12 hours. Considering the removal efficiency, it is sufficient to stand for 1 hour or more, but the standing time is determined from the above range from the viewpoint of the apparatus and operation. The removal efficiency does not improve so much even if the product is left standing above the upper limit. By this first standing, the heavy metal remaining after dissolving in water precipitates together with the precipitation of the calcium salt. This coprecipitation effect further reduces the concentration of heavy metals dissolved in water.
Subsequently, the primary stationary product containing the liquid and the precipitate is subjected to primary solid-liquid separation by centrifugation, filter press or the like (step 19a). By this primary solid-liquid separation, a primary filtrate 21a and a primary residue 24a are obtained. The primary filtrate 21a is further allowed to stand for a second time (step 18b). This standing is also performed for 30 minutes or more, preferably 1 to 12 hours. Considering the removal efficiency, it is sufficient to stand for 1 hour or more, but the standing time is determined from the above range from the viewpoint of the apparatus and operation. The removal efficiency does not improve so much even if the product is left standing above the upper limit. By this second standing, the dissolved supersaturated calcium salt is precipitated, but the heavy metal remaining in the first filtrate also remains together with the calcium salt precipitation. Precipitate. This coprecipitation effect further reduces the concentration of heavy metals dissolved in the primary filtrate.

更に続いて液と沈殿物を含む第２次静置物を遠心分離、フィルタプレス等により第２次固液分離する（工程１９ｂ）。この第２次固液分離により第２次ろ液２１ｂと第２次残渣２４ｂが得られる。第２次ろ液２１ｂを加熱することによりその水分を蒸発し、液に溶解していた物を晶析させる（工程２２）。得られた固形物２３にはカリウム、ナトリウム等のアルカリ金属と、塩素、臭素等のハロゲン類が多量に含まれるので、この固形物により肥料の原料や化学原料が製造される。一方第１次及び第２次固液分離により得られた残渣２４ａ，２４ｂには若干重金属を含むものの大部分がカルシウム化合物、シリカから構成されているので、これらの残渣により製錬原料又はセメント原料が製造される。 Subsequently, the secondary stationary product containing the liquid and the precipitate is subjected to secondary solid-liquid separation by centrifugation, filter press or the like (step 19b). By this secondary solid-liquid separation, a secondary filtrate 21b and a secondary residue 24b are obtained. The secondary filtrate 21b is heated to evaporate its water and crystallize what was dissolved in the liquid (step 22). Since the obtained solid 23 contains a large amount of alkali metals such as potassium and sodium and halogens such as chlorine and bromine, a fertilizer raw material and a chemical raw material are produced from the solid. On the other hand, most of the residues 24a and 24b obtained by the primary and secondary solid-liquid separations contain some heavy metals, but are composed of calcium compounds and silica. Is manufactured.

次に本発明の実施例を説明する。
＜実施例１＞
表１に示すセメントキルンダスト１００ｇと水１リットルとを混合しスラリーを調製した。図１の破線に示すように、このスラリーの一部を抜き取りろ過した後、ｐＨ１２．０のろ液１を得た。その後、このスラリーに１５％ＣＯ₂−空気混合ガスを吹き込んでスラリーのｐＨを１０．５に調整した。ｐＨを調整した後、１５％ＣＯ₂−空気混合ガスを吹き込みを止め、図１の破線に示すように、スラリーの一部を抜き取りろ過した後、ろ液２を得た。ｐＨ調整したスラリーを１時間第１次静置した後、第１次静置物をフィルタプレスにより第１次固液分離した。図１の破線に示すように、このときのろ液の一部を抜き取りろ液３とした。第１次固液分離で得られたろ液を更に５時間第２静置した。この静置により析出した沈殿物を第２次固液分離した。図１の破線に示すように、このときのろ液の一部を抜き取りろ液４とした。実施例１で得られたろ液１、ろ液２、ろ液３及びろ液４をｐＨ測定し、更に各ろ液の重金属成分についてＩＣＰ発光分光分析法により化学分析を行った。その結果を表２に示す。 Next, examples of the present invention will be described.
<Example 1>
A slurry was prepared by mixing 100 g of cement kiln dust shown in Table 1 and 1 liter of water. As shown by the broken line in FIG. 1, a part of this slurry was extracted and filtered, and then a filtrate 1 having a pH of 12.0 was obtained. Thereafter, a 15% CO ₂ -air mixed gas was blown into the slurry to adjust the pH of the slurry to 10.5. After adjusting the pH, blowing of 15% CO ₂ -air mixed gas was stopped, and a portion of the slurry was extracted and filtered as shown by the broken line in FIG. The slurry whose pH was adjusted was allowed to stand for the first time for 1 hour, and then the first stationary product was subjected to primary solid-liquid separation with a filter press. As shown by the broken line in FIG. 1, a part of the filtrate at this time was extracted and designated as filtrate 3. The filtrate obtained by the first solid-liquid separation was further allowed to stand for a second for 5 hours. The precipitate deposited by this standing was subjected to secondary solid-liquid separation. As shown by the broken line in FIG. 1, a part of the filtrate at this time was extracted and designated as filtrate 4. The filtrate 1, filtrate 2, filtrate 3 and filtrate 4 obtained in Example 1 were measured for pH, and the heavy metal components of each filtrate were further chemically analyzed by ICP emission spectrometry. The results are shown in Table 2.

表２から、炭酸ガスを吹き込むことにより、液中の重金属濃度は低下し、ろ液２とろ液３の各分析値の比較から、水酸化物や炭酸塩の形態で重金属を除去した後において、静置工程のカルシウム塩による共沈効果で重金属濃度が更に低下することが判った。またろ液３とろ液４の各分析値の比較から、第２次ろ液を十分に静置することにより、重金属成分を検出限界以下に低下することができた。 From Table 2, by blowing carbon dioxide gas, the heavy metal concentration in the liquid decreases, and after removing heavy metals in the form of hydroxide or carbonate from the comparison of each analysis value of filtrate 2 and filtrate 3, It was found that the heavy metal concentration was further reduced by the coprecipitation effect of the calcium salt in the stationary process. Moreover, from the comparison of the analysis values of the filtrate 3 and the filtrate 4, the heavy metal component could be lowered below the detection limit by allowing the secondary filtrate to stand sufficiently.

＜実施例２＞
表３に示すセメントキルンダスト１００ｇと水１リットルとを混合しスラリーを調製した。図１の破線に示すように、このスラリーの一部を抜き取りろ過した後、ろ液１を得た。その後、このスラリーに１０％ＣＯ₂−空気混合ガスを吹き込んでスラリーのｐＨを１０に調整した。それ以外は実施例１と同様にダストを処理するとともに、実施例２で得られたろ液１、ろ液２、ろ液３及びろ液４をｐＨ測定し、更に各ろ液の重金属成分について実施例１と同様に化学分析を行った。その結果を表４に示す。 <Example 2>
A slurry was prepared by mixing 100 g of cement kiln dust shown in Table 3 and 1 liter of water. As shown by the broken line in FIG. 1, a portion of this slurry was extracted and filtered, and then filtrate 1 was obtained. Thereafter, a 10% CO ₂ -air mixed gas was blown into the slurry to adjust the pH of the slurry to 10. Otherwise, dust was treated in the same manner as in Example 1, pH of filtrate 1, filtrate 2, filtrate 3 and filtrate 4 obtained in Example 2 were measured, and the heavy metal components of each filtrate were further measured. Chemical analysis was performed as in Example 1. The results are shown in Table 4.

表4から実施例１と同様に、炭酸ガスを吹き込むことにより、液中の重金属濃度は低下し、ろ液２とろ液３の各分析値の比較から、水酸化物や炭酸塩の形態で重金属を除去した後において、静置工程のカルシウム塩による共沈効果で重金属濃度が更に低下することが判った。またろ液３とろ液４の各分析値の比較から、第２次ろ液を十分に静置することにより、重金属成分を検出限界以下に低下することができた。 As in Example 1 from Table 4, by blowing carbon dioxide gas, the heavy metal concentration in the liquid decreases, and from the comparison of the analytical values of filtrate 2 and filtrate 3, heavy metal in the form of hydroxide or carbonate It was found that the heavy metal concentration was further reduced by the coprecipitation effect of the calcium salt in the standing step after the removal. Moreover, from the comparison of the analysis values of the filtrate 3 and the filtrate 4, the heavy metal component could be lowered below the detection limit by allowing the secondary filtrate to stand sufficiently.

＜実施例３＞
実施例２と同じ表３に示すセメントキルンダスト１００ｇと水１リットルとを混合しスラリーを調製した。図１の破線に示すように、このスラリーの一部を抜き取りろ過した後、ろ液１を得た。その後、このスラリーに１０％ＣＯ₂−空気混合ガスを吹き込んでスラリーのｐＨを１１に調整した。それ以外は実施例１と同様にダストを処理するとともに、実施例３で得られたろ液１、ろ液２、ろ液３及びろ液４をｐＨ測定し、更に各ろ液の重金属成分について実施例１と同様に化学分析を行った。その結果を表５に示す。 <Example 3>
A slurry was prepared by mixing 100 g of cement kiln dust and 1 liter of water shown in Table 3 as in Example 2. As shown by the broken line in FIG. 1, a portion of this slurry was extracted and filtered, and then filtrate 1 was obtained. Thereafter, a 10% CO ₂ -air mixed gas was blown into the slurry to adjust the pH of the slurry to 11. Otherwise, dust was treated in the same manner as in Example 1, pH of filtrate 1, filtrate 2, filtrate 3 and filtrate 4 obtained in Example 3 were measured, and the heavy metal components of each filtrate were further measured. Chemical analysis was performed as in Example 1. The results are shown in Table 5.

表５から実施例１と同様に、炭酸ガスを吹き込むことにより、液中の重金属濃度は低下し、ろ液２とろ液３の各分析値の比較から、水酸化物や炭酸塩の形態で重金属を除去した後において、静置工程のカルシウム塩による共沈効果で重金属濃度が更に低下することが判った。またろ液３とろ液４の各分析値の比較から、第２次ろ液を十分に静置することにより、重金属成分を検出限界以下に低下することができた。 As in Example 1 from Table 5, by blowing carbon dioxide gas, the heavy metal concentration in the liquid decreases, and from comparison of the analytical values of filtrate 2 and filtrate 3, heavy metal in the form of hydroxide or carbonate It was found that the heavy metal concentration was further reduced by the coprecipitation effect of the calcium salt in the standing step after the removal. Moreover, from the comparison of the analysis values of the filtrate 3 and the filtrate 4, the heavy metal component could be lowered below the detection limit by allowing the secondary filtrate to stand sufficiently.

＜参考例１＞
表６に示すセメントキルンダスト１００ｇと水１リットルとを混合しスラリーを調製した。図１の破線に示すように、このスラリーの一部を抜き取りろ過した後、ろ液１を得た。その後、このスラリーに１０％ＣＯ₂−空気混合ガスを吹き込んでスラリーのｐＨを１２．３に調整した。それ以外は実施例１と同様にダストを処理するとともに、参考例１で得られたろ液１、ろ液２、ろ液３及びろ液４をｐＨ測定し、更に各ろ液の重金属成分について実施例１と同様に化学分析を行った。その結果を表７に示す。 < Reference Example 1 >
A slurry was prepared by mixing 100 g of cement kiln dust shown in Table 6 and 1 liter of water. As shown by the broken line in FIG. 1, a portion of this slurry was extracted and filtered, and then filtrate 1 was obtained. Thereafter, a 10% CO ₂ -air mixed gas was blown into the slurry to adjust the pH of the slurry to 12.3. Otherwise, the dust was treated in the same manner as in Example 1 , pH of filtrate 1, filtrate 2, filtrate 3 and filtrate 4 obtained in Reference Example 1 were measured, and the heavy metal components of each filtrate were further measured. Chemical analysis was performed as in Example 1. The results are shown in Table 7.

表７から実施例１と同様に、炭酸ガスを吹き込むことにより、液中の重金属濃度は低下し、ろ液２とろ液３の各分析値の比較から、水酸化物や炭酸塩の形態で重金属を除去した後において、静置工程のカルシウム塩による共沈効果でＰｂ以外の重金属成分を検出限界以下に低下することができた。またろ液３とろ液４の各分析値の比較から、第２次ろ液を十分に静置することにより、Ｐｂ成分も検出限界以下に低下することができた。 As in Example 1 from Table 7, the concentration of heavy metals in the liquid is reduced by blowing carbon dioxide gas. From the comparison of the analytical values of filtrate 2 and filtrate 3, heavy metals in the form of hydroxides and carbonates. After removal, heavy metal components other than Pb could be reduced below the detection limit due to the coprecipitation effect of the calcium salt in the standing step. Moreover, from the comparison of the analysis values of the filtrate 3 and the filtrate 4, the Pb component could be lowered below the detection limit by sufficiently leaving the secondary filtrate.

＜実施例４＞
実施例１、実施例２及び参考例１の各ろ液４（第２次ろ液）を加熱し、水分を蒸発させ、ＫＣｌ含有結晶を得た。これらの分析値を表８に示す。表８からＫＣｌ含有結晶中、カリウムの含有量はいずれも４３重量％であり、Ｋ₂Ｏ換算にすると５０重量％以上の値を示し、塩化カリウム肥料の規格を満足するものであった。 <Example 4 >
Each filtrate 4 (secondary filtrate) of Example 1, Example 2 and Reference Example 1 was heated to evaporate water, thereby obtaining KCl-containing crystals. These analytical values are shown in Table 8. From Table 8, in the KCl-containing crystals, the content of potassium was 43% by weight, and when converted to K ₂ O, it showed a value of 50% by weight or more and satisfied the standard of potassium chloride fertilizer.

＜実施例６＞
実施例１、実施例２、実施例３及び参考例１の各第１次残渣及び第２次残渣を化学分析したところ、すべての残渣について、Ｃａ化合物、ＳｉＯ₂が主成分であり、セメント原料又は製錬の原料として再利用可能なものであった。
<Example 6>
When each primary residue and secondary residue of Example 1, Example 2, Example 3 and Reference Example 1 were chemically analyzed, Ca compounds and SiO ₂ were the main components in all the residues, and the cement raw material Or it was reusable as a raw material for smelting.

本発明は、キルンダスト、或いは焼却炉、溶融炉、ガス化溶融炉等から得られた飛灰、溶融飛灰、ダスト等の処理に利用できる。また上記キルンダスト等から、肥料原料、化学原料、製錬原料、セメント原料等を製造できる。 INDUSTRIAL APPLICABILITY The present invention can be used for treating kiln dust, fly ash obtained from an incinerator, melting furnace, gasification melting furnace or the like, molten fly ash, dust and the like. Further, fertilizer raw materials, chemical raw materials, smelting raw materials, cement raw materials and the like can be produced from the kiln dust and the like.

本発明のダスト処理工程を示す図。The figure which shows the dust treatment process of this invention.

Explanation of symbols

１０ダスト
１３水
１４スラリーの調製工程
１６炭酸ガス
１７重金属の沈殿工程
１８ａ，１８ｂ静置による残留重金属のカルシウム塩との共沈工程
１９ａ，１９ｂ固液分離工程
２１ａ，２１ｂろ液
２２蒸発・晶析工程
２３固形物
２４ａ，２４ｂ残渣 10 Dust 13 Water 14 Slurry Preparation Process 16 Carbon Dioxide 17 Heavy Metal Precipitation Process 18a, 18b Co-precipitation Process with Calcium Salt of Residual Heavy Metal by Standing 19a, 19b Solid-Liquid Separation Process 21a, 21b Filtrate 22 Evaporation / crystallization Step 23 Solid matter 24a, 24b Residue

Claims

A dust having a calcium content of 5% by weight or more and containing at least a heavy metal such as Cd, Pb, Zn, and Cu is mixed with water (13) to prepare a slurry having a pH of 12 or more, and the pH value is adjusted. A step (14) in which most of Cd and Cu are converted into a water-insoluble hydroxide in a slurry having a pH of 12 or more, and carbon dioxide gas (16) is blown into the slurry having a pH value of 12 or more to adjust the pH of the slurry. the Pb that to a range of less than pH values 10 to 11.5 at the time of slurry preparation by reducing dissolved in the slurry, reduce the water solubility of the Zn, precipitated in the form of hydroxides or carbonates And, the step (17) of precipitating slightly dissolved Cd in the form of carbonate, and the slurry into which the carbon dioxide gas has been blown is allowed to stand for 30 minutes to 12 hours to dissolve in the slurry. Remaining A primary standing step (18a) in which heavy metal is precipitated by a coprecipitation effect with a calcium salt to further reduce the concentration of the heavy metal dissolved in the slurry, and the stationary product in the first standing step is a solid liquid. The primary solid-liquid separation step (19a) to be separated and the primary filtrate (21a) obtained by the primary solid-liquid separation are allowed to stand within a range of 30 minutes to 12 hours, Heavy metal dissolved in the primary filtrate is further precipitated by coprecipitation with the supersaturated calcium salt dissolved in the primary filtrate, and dissolved in the primary filtrate. A dust treatment method comprising: a second stationary step (18b) for further reducing the concentration; and a second solid-liquid separation step (19b) for solid-liquid separation of the stationary product in the second stationary step.

A step (22) for evaporating and crystallizing the secondary filtrate (21b) obtained by the second solid-liquid separation, and a fertilizer raw material or a chemical raw material from the solid matter (23) obtained by the evaporation and crystallization. The processing method according to claim 1, further comprising:

The processing method of Claim 1 which further includes the process of producing | generating a smelting raw material or a cement raw material from the residue (24a, 24b) obtained by either or both of the primary or secondary solid-liquid separation.

A dust having a calcium content of 5% by weight or more and containing at least a heavy metal such as Cd, Pb, Zn, and Cu is mixed with water (13) to prepare a slurry having a pH of 12 or more, and the pH value is adjusted. A step (14) in which most of Cd and Cu are converted into a water-insoluble hydroxide in a slurry having a pH of 12 or more, and carbon dioxide gas (16) is blown into the slurry having a pH value of 12 or more to adjust the pH of the slurry. the Pb that to a range of less than pH values 10 to 11.5 at the time of slurry preparation by reducing dissolved in the slurry, reduce the water solubility of the Zn, precipitated in the form of hydroxides or carbonates And, the step (17) of precipitating slightly dissolved Cd in the form of carbonate, and the slurry into which the carbon dioxide gas has been blown is allowed to stand for 30 minutes to 12 hours to dissolve in the slurry. Remaining A primary standing step (18a) in which heavy metal is precipitated by a coprecipitation effect with a calcium salt to further reduce the concentration of the heavy metal dissolved in the slurry, and the stationary product in the first standing step is a solid liquid. The primary solid-liquid separation step (19a) to be separated and the primary filtrate (21a) obtained by the primary solid-liquid separation are allowed to stand within a range of 30 minutes to 12 hours, Heavy metal dissolved in the primary filtrate is further precipitated by coprecipitation with the supersaturated calcium salt dissolved in the primary filtrate, and dissolved in the primary filtrate. A second stationary step (18b) for further reducing the concentration, a second solid-liquid separation step (19b) for solid-liquid separation of the stationary product in the second stationary step, and the second solid-liquid separation. A step (22) for evaporating and crystallizing the secondary filtrate (21b) obtained by the above step, and a fertilizer raw material or a chemical raw material from the solid matter (23) obtained by the evaporation and crystallization. Method for producing a fertilizer material or chemical raw materials and the step of.

A dust having a calcium content of 5% by weight or more and containing at least a heavy metal such as Cd, Pb, Zn, and Cu is mixed with water (13) to prepare a slurry having a pH of 12 or more, and the pH value is adjusted. A step (14) in which most of Cd and Cu are converted into a water-insoluble hydroxide in a slurry having a pH of 12 or more, and carbon dioxide gas (16) is blown into the slurry having a pH value of 12 or more to adjust the pH of the slurry. the Pb that to a range of less than pH values 10 to 11.5 at the time of slurry preparation by reducing dissolved in the slurry, reduce the water solubility of the Zn, precipitated in the form of hydroxides or carbonates And, the step (17) of precipitating slightly dissolved Cd in the form of carbonate, and the slurry into which the carbon dioxide gas has been blown is allowed to stand for 30 minutes to 12 hours to dissolve in the slurry. Remaining A primary standing step (18a) in which heavy metal is precipitated by a coprecipitation effect with a calcium salt to further reduce the concentration of the heavy metal dissolved in the slurry, and the stationary product in the first standing step is a solid liquid. The primary solid-liquid separation step (19a) to be separated and the primary filtrate (21a) obtained by the primary solid-liquid separation are allowed to stand within a range of 30 minutes to 12 hours, Heavy metal dissolved in the primary filtrate is further precipitated by coprecipitation with the supersaturated calcium salt dissolved in the primary filtrate, and dissolved in the primary filtrate. A second stationary step (18b) for further reducing the concentration, a second solid-liquid separation step (19b) for solid-liquid separation of the stationary product in the second stationary step, and the first or second step. A smelting raw material or cement containing a step of producing a smelting raw material or a cement raw material from the residue (24a, 24b) obtained by either or both of the following solid-liquid separations Method of manufacturing a door raw materials.