JP2016068015A - Production method of burned product - Google Patents
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本発明は、砒素を含む原料を用いた焼成物の製造方法であって、砒素の溶出を抑制した焼成物の製造方法に関する。 The present invention relates to a method for producing a fired product using a raw material containing arsenic, and relates to a method for producing a fired product in which elution of arsenic is suppressed.
近年の環境保全意識の高まりや、逼迫する最終処分場問題の要請から、砒素等の重金属に汚染された土壌や廃棄物の無害化、および有効利用に関する技術の重要性が増している。
しかし、砒素は陰イオン（砒酸イオンおよび亜砒酸イオン）の形態で自然界に存在し、従来多用されているキレート処理が無効なため、重金属の中でも砒素の安定化処理は難しい。また、砒素を含む土壌、廃棄物、または天然鉱物等の有効利用を図るため、これらを原料に用いて製造した焼成物を骨材等に使用する場合、該焼成物から砒素が溶出するおそれがある。
With the recent increase in awareness of environmental conservation and the demand for tight final disposal sites, the importance of technology for detoxification and effective use of soil and waste contaminated with heavy metals such as arsenic is increasing.
However, arsenic is present in nature in the form of anions (arsenate ions and arsenite ions), and the chelation treatment that has been frequently used is ineffective, so it is difficult to stabilize arsenic among heavy metals. In addition, in order to effectively use arsenic-containing soil, waste, natural minerals, etc., when a fired product manufactured using these materials is used as an aggregate, there is a risk that arsenic may elute from the fired product. is there.
そこで、砒素の溶出を抑制する方法が必要であり、以下の方法が知られている。
例えば、非特許文献１に記載の方法は、各種のセメントと、鉄、バリウム、マンガン、またはマグネシウムの塩との混合物を用いて、砒素で汚染された砂質土壌を処理する方法であり、砒素の溶出抑制に有効とされている。そして、これらの塩の中でも、硫酸第１鉄と第１種ポルトランドセメントの組み合わせが最も有効とされている。
また、特許文献１に記載の方法は、消石灰と、鉄化合物とを主成分とする重金属類溶出抑制剤を、重金属類の汚染媒体に添加して混練処理を行う方法であり、さらに、該重金属類溶出抑制剤と、銀、バリウム、ベリリウム、セリウム、コバルト、銅、マグネシウム、マンガン、ニッケル、ストロンチウム、亜鉛の少なくとも一つの水溶性の硫酸塩、塩化物、硝酸塩、水酸化物、酸化物、またはアンモニウム塩とを、重金属の汚染媒体に添加して混練処理を行う方法である。
Therefore, a method for suppressing arsenic elution is required, and the following methods are known.
For example, the method described in Non-Patent Document 1 is a method of treating sandy soil contaminated with arsenic using a mixture of various cements and a salt of iron, barium, manganese, or magnesium. It is effective for the suppression of elution. Among these salts, a combination of ferrous sulfate and first type Portland cement is most effective.
In addition, the method described in Patent Document 1 is a method in which a heavy metal elution inhibitor mainly composed of slaked lime and an iron compound is added to a heavy metal contamination medium to perform a kneading process. An elution inhibitor and at least one water-soluble sulfate, chloride, nitrate, hydroxide, oxide, or silver, barium, beryllium, cerium, cobalt, copper, magnesium, manganese, nickel, strontium, zinc, or In this method, an ammonium salt is added to a heavy metal contamination medium and kneaded.
ところが、本発明の対象物は、砒素を含む原料を用いた焼成物であり、該焼成物の液性はｐＨ１１〜１２程度と高い点が前記砂質土壌と異なる。また、ｐＨ１１〜１２程度のアルカリ性条件下では、前記硫酸第１鉄等の鉄化合物は速やかにゲルを生成し赤褐色になるため、以下の（i）〜（iii）の問題がある。
（i）製造現場で発生する赤褐色の汚泥および汚水は、清掃および排水処理の負担を増加させる。
（ii）硫酸第１鉄等は酸性物質であるため、鉄製の製造装置が腐食し易い。
（iii）焼成物が白色または淡色である程、着色や着色ムラが目立ち、その分、商品価値は低下する。
さらに、特許文献１に記載の方法は、該文献中の表１〜３に示すように、砒素の埋立基準値である０．３ｍｇ／Ｌを満たすとしても、さらに厳しい砒素の環境基準値である０．０１ｍｇ／Ｌ以下を満たすか否かについて、非特許文献１の記載からは不明である。
However, the object of the present invention is a fired product using a raw material containing arsenic, and the liquid property of the fired product is different from the sandy soil in that it has a high pH of about 11-12. Moreover, since the iron compound such as ferrous sulfate rapidly forms a gel and becomes reddish brown under alkaline conditions of about pH 11 to 12, there are the following problems (i) to (iii).
(I) Reddish brown sludge and sewage generated at the manufacturing site increase the burden of cleaning and wastewater treatment.
(Ii) Since ferrous sulfate and the like are acidic substances, iron manufacturing equipment is easily corroded.
(Iii) As the fired product is white or light-colored, coloring and uneven coloring are more conspicuous, and the commercial value is reduced accordingly.
Furthermore, as shown in Tables 1 to 3 in the document, the method described in Patent Document 1 is a more strict arsenic environmental reference value even if the arsenic landfill reference value of 0.3 mg / L is satisfied. Whether or not it satisfies 0.01 mg / L or less is not clear from the description of Non-Patent Document 1.
そこで、本発明は、砒素を含む原料を用いた焼成物の製造方法であって、砒素の溶出を抑制した焼成物の製造方法を提供することを課題とする。 Therefore, an object of the present invention is to provide a method for manufacturing a fired product using a raw material containing arsenic, and suppressing the elution of arsenic.
本発明者らは、前記解題を解決するために種々の方法を検討した結果、下記の構成を有する焼成物の製造方法は、前記課題を解決できることを見い出し、本発明を完成させた。すなわち、本発明は以下のとおりである。
［１］砒素を含む原料を用いて１０００〜１２５０℃で焼成して得た焼成物を、４００℃以下に冷却した後、該冷却した焼成物を、２価のマンガン水溶液に接触させて、砒素の溶出が抑制された焼成物を得る、焼成物の製造方法。
［２］前記２価のマンガン水溶液に接触させる工程が、２価のマンガン水溶液に浸漬する工程である、前記［１］に記載の焼成物の製造方法。
［３］前記２価のマンガン水溶液に接触させる工程が、２価のマンガン水溶液を噴霧、散布、または散水する工程である、前記［１］に記載の焼成物の製造方法。
［４］前記２価のマンガン水溶液に接触させる工程が、表面乾燥状態にした焼成物に対し、２価のマンガン水溶液を噴霧、散布、または散水する工程である、前記［３］に記載の焼成物の製造方法。
［５］前記焼成物中の砒素の含有量が、焼成物１ｋｇあたり１００ｍｇ以下である、前記［１］〜［４］のいずれかに記載の焼成物の製造方法。
［６］前記焼成物中の２価のマンガンの含有量が、焼成物１トンあたり１〜１００モルである、前記［１］〜［５］のいずれかに記載の焼成物の製造方法。
As a result of studying various methods for solving the above-mentioned problems, the present inventors have found that a method for producing a fired product having the following configuration can solve the above-mentioned problems, and completed the present invention. That is, the present invention is as follows.
[1] A fired product obtained by firing at 1000 to 1250 ° C. using a raw material containing arsenic is cooled to 400 ° C. or lower, and then the cooled fired product is brought into contact with a divalent manganese aqueous solution to obtain arsenic. The manufacturing method of a baked product which obtains the baked product in which the elution of was suppressed.
[2] The method for producing a fired product according to [1], wherein the step of bringing the divalent manganese aqueous solution into contact with the divalent manganese aqueous solution is a step of immersing in the divalent manganese aqueous solution.
[3] The method for producing a fired product according to [1], wherein the step of bringing the divalent manganese aqueous solution into contact is a step of spraying, spraying, or sprinkling the divalent manganese aqueous solution.
[4] The firing according to [3], wherein the step of contacting with the divalent manganese aqueous solution is a step of spraying, spraying, or sprinkling the divalent manganese aqueous solution on the fired product that has been dried. Manufacturing method.
[5] The method for producing a fired product according to any one of [1] to [4], wherein the content of arsenic in the fired product is 100 mg or less per 1 kg of the fired product.
[6] The method for producing a fired product according to any one of [1] to [5], wherein the content of divalent manganese in the fired product is 1 to 100 mol per ton of the fired product.
本発明の焼成物の製造方法は、砒素の溶出を抑制した焼成物を製造することができる。 The method for producing a fired product of the present invention can produce a fired product in which elution of arsenic is suppressed.
本発明は、前記のとおり、砒素を含む原料を用いて１０００〜１２５０℃で焼成して得た焼成物を、４００℃以下に冷却した後、該冷却した焼成物を、２価のマンガン水溶液に接触させて、砒素の溶出が抑制された焼成物を得る、焼成物の製造方法等である。以下、本発明を各構成要素に分けて詳細に説明する。 In the present invention, as described above, the fired product obtained by firing at 1000 to 1250 ° C. using a raw material containing arsenic is cooled to 400 ° C. or lower, and then the cooled fired product is converted into a divalent manganese aqueous solution. For example, a method for producing a fired product in which a fired product in which elution of arsenic is suppressed is obtained. Hereinafter, the present invention will be described in detail for each component.
（１）原料
本発明において用いる原料は、土壌、産業廃棄物、一般廃棄物、天然頁岩、汚泥、石炭灰、火山岩、および焼却灰等からなる群より選ばれる１種以上であり、砒素を含むものである。
前記原料が、固形物の場合は粉砕し、また粉体の場合は成形（造粒を含む。）するのが好ましい。粉砕装置は、ジョークラッシャー、ボールミル、ローラミル、またはロッドミルが挙げられ、成形装置は、パンペレタイザー、ブリケットマシン、ロールプレス機、および押出し成形機等が挙げられる。また、成形性を高めるために原料にリグニンやベントナイト等の粘結剤を混合してもよい。また、焼成物が軽量骨材である場合、ＳｉＣ等の発泡剤を混合してもよい。
(1) Raw material The raw material used in the present invention is at least one selected from the group consisting of soil, industrial waste, general waste, natural shale, sludge, coal ash, volcanic rock, and incinerated ash, and contains arsenic. It is a waste.
When the raw material is a solid material, it is preferably pulverized, and when the raw material is a powder, it is preferably molded (including granulation). Examples of the pulverizer include a jaw crusher, a ball mill, a roller mill, and a rod mill. Examples of the molding apparatus include a pan pelletizer, a briquette machine, a roll press machine, and an extrusion molding machine. Moreover, you may mix binders, such as lignin and a bentonite, in order to improve a moldability. Moreover, when the fired product is a lightweight aggregate, a foaming agent such as SiC may be mixed.
（２）焼成温度と焼成時間
本発明における焼成温度は１０００〜１２５０℃である。該温度が１０００℃未満では焼成物の強度が低く、１２５０℃を超えると溶融して操業できない場合がある。また、焼成物が軽量骨材である場合、前記温度範囲内であれば、還元雰囲気になった原料の内部でガスが発生し、半溶融状態になった原料中の粒子が膨張して軽量化する。なお、前記焼成温度は、好ましくは１０５０〜１２００℃である。
また、本発明における焼成時間は、原料の投入量や、焼成装置の大きさおよび焼成の性能等にもよるが、焼成度と生産効率のバランスを考慮すると、好ましくは２０分〜２時間、より好ましくは３０分〜１時間である。
また、本発明において用いる焼成装置は、ロータリーキルン、および電気炉等が挙げられる。
(2) Baking temperature and baking time The baking temperature in this invention is 1000-1250 degreeC. If the temperature is less than 1000 ° C, the strength of the fired product is low, and if it exceeds 1250 ° C, it may melt and be unable to operate. Also, when the fired product is a lightweight aggregate, if it is within the above temperature range, gas is generated inside the raw material in a reducing atmosphere, and the particles in the raw material in a semi-molten state expand and lighten. To do. The firing temperature is preferably 1050 to 1200 ° C.
The firing time in the present invention is preferably 20 minutes to 2 hours in consideration of the balance between the degree of firing and the production efficiency, although it depends on the input amount of the raw material, the size of the firing apparatus and the firing performance. Preferably, it is 30 minutes to 1 hour.
Examples of the baking apparatus used in the present invention include a rotary kiln and an electric furnace.
（３）冷却温度
本発明において焼成物の冷却温度は４００℃以下である。冷却温度が４００℃を超えると、水が焼成物の表面で蒸発して２価のマンガンが析出し、２価のマンガンが焼成物の内部まで浸透し難いほか、焼成物を２価のマンガン水溶液中に浸漬する場合、該水溶液中の水が急激に蒸発して２価のマンガンの濃度管理が難しくなる場合がある。なお、該冷却温度は、好ましくは３５０℃以下、より好ましくは３００℃以下である。
なお、焼成物の冷却は、放置して空冷してもよいが、冷却を早めるためエアークーラーを用いるとよい。
(3) Cooling temperature In this invention, the cooling temperature of a baked product is 400 degrees C or less. When the cooling temperature exceeds 400 ° C., water evaporates on the surface of the fired product, divalent manganese is deposited, and it is difficult for the divalent manganese to penetrate into the fired product. When immersed in water, the water in the aqueous solution may rapidly evaporate, making it difficult to control the concentration of divalent manganese. In addition, this cooling temperature becomes like this. Preferably it is 350 degrees C or less, More preferably, it is 300 degrees C or less.
The fired product may be cooled by leaving it alone, but an air cooler may be used to speed up the cooling.
（４）接触工程
該工程は、冷却した焼成物を２価のマンガン水溶液に接触させて、２価のマンガンが内部に浸透した焼成物を得る工程である。
ここで、前記接触工程は、
（i）冷却した焼成物を２価のマンガン水溶液に浸漬する工程、
（ii）冷却した焼成物に対し２価のマンガン水溶液を噴霧、散布、または散水する工程、
または、
（iii）冷却して表面乾燥状態にした焼成物に対し、２価のマンガン水溶液を噴霧、散布、または散水する工程
である。また、前記（iii）に記載の表面乾燥状態とは、含水状態の表面から、水が完全に除かれた状態をいい、例えば、含水状態の焼成物を、しばらく静置するか、風乾するか、または布で拭くことにより、表面に水が存在しない状態をいう。なお、前記（i）〜（iii）の工程は、任意の後工程として、さらに風乾や加熱乾燥等の乾燥工程を含んでもよい。
前記（i）〜（iii）の工程は、具体的には、
（i）の工程は、例えば、焼成物をコンベアー等に乗せて運搬し、焼成物の温度が４００℃以下になった時点で、２価のマンガン水溶液を入れた水槽内に投入して浸漬する。ただし、（i）の工程は、水槽内の水が蒸発するため、適宜、水槽内に、水、水溶液、または水と２価のマンガン化合物を供給する。
（ii）の工程は、例えば、焼成物をコンベアー等に乗せて運搬し、焼成物の温度が４００℃以下になった時点で、２価のマンガン水溶液を噴霧、散布、または散水する。ここで、散水装置は、焼成物全体にマンガン水溶液が接触できるため、シャワーが好適である。
（iii）の工程は、前記（ii）の工程に類似するが、（ii）の工程と異なるのは、２価のマンガン水溶液を噴霧、散布、または散水する前に、焼成物を含水状態にする工程を含む点である。該含水状態は、工業用水などの水を浸漬、噴霧、散布、または散水することにより得られる。水を浸漬する場合、焼成後に１００〜４００℃まで冷却された焼成物に対して水を浸漬すると、迅速に焼成物の内部まで含水させることができる。
この含水処理を付加したのは、含水状態の焼成物はマンガンの浸透性が向上することを経験的に見出したことによる。この浸透性が向上する理由は、焼成物内に存在する水を通じてマンガンが拡散するためであると推察する。そして、前記焼成物の含水状態は、好ましくは表面乾燥状態であり、より好ましくは該表面乾燥状態であって煮沸吸水率に対して３０〜９５％まで含水した状態である。ここで、前記煮沸吸水率とは、焼成物を２時間煮沸したときの吸水率をいい、ＪＩＳ ７２０９「プラスチック−吸水率の求め方」に準じ下記式で表わされる。
煮沸吸水率＝１００×（ｍ２−ｍ１）／ｍ１
ただし、ｍ１は絶乾状態の焼成物の質量を表わし、ｍ２は吸水後の焼成物の質量を表わす。
(4) Contacting step This step is a step of bringing the cooled fired product into contact with a divalent manganese aqueous solution to obtain a fired product in which divalent manganese has penetrated.
Here, the contact step includes
(I) a step of immersing the cooled fired product in a divalent manganese aqueous solution;
(Ii) a step of spraying, spraying or sprinkling a divalent manganese aqueous solution on the cooled fired product,
Or
(Iii) A step of spraying, spraying, or sprinkling a divalent manganese aqueous solution on the fired product that has been cooled to a dry surface. Moreover, the surface dry state described in the above (iii) means a state in which water is completely removed from the surface of the water-containing state. For example, whether the fired product in the water-containing state is left for a while or air-dried. Or a state where water is not present on the surface by wiping with a cloth. The steps (i) to (iii) may further include a drying step such as air drying or heat drying as an optional subsequent step.
Specifically, the steps (i) to (iii)
In the step (i), for example, the fired product is transported on a conveyor or the like, and when the temperature of the fired product becomes 400 ° C. or lower, the product is immersed in a water tank containing a divalent manganese aqueous solution. . However, since the water in the water tank evaporates in the step (i), water, an aqueous solution, or water and a divalent manganese compound are appropriately supplied into the water tank.
In the step (ii), for example, the fired product is transported on a conveyor or the like, and when the temperature of the fired product becomes 400 ° C. or lower, the divalent manganese aqueous solution is sprayed, sprayed, or sprinkled. Here, the watering device is preferably a shower because the aqueous manganese solution can contact the entire fired product.
The step (iii) is similar to the step (ii), but the step (ii) is different from the step (ii) in that the fired product is brought into a water-containing state before the divalent manganese aqueous solution is sprayed, sprayed or sprinkled. It is a point including the process to do. The water-containing state can be obtained by immersing, spraying, spraying, or watering water such as industrial water. When water is immersed, when water is immersed in a fired product cooled to 100 to 400 ° C. after firing, the inside of the fired product can be quickly hydrated.
The reason why this water treatment was added is that it has been found empirically that the baked product in a water-containing state has improved manganese permeability. The reason why this permeability is improved is presumed to be that manganese diffuses through the water present in the fired product. The water content of the fired product is preferably a surface dry state, more preferably the surface dry state and a water content of 30 to 95% with respect to boiling water absorption. Here, the boiling water absorption rate refers to the water absorption rate when the fired product is boiled for 2 hours, and is expressed by the following formula according to JIS 7209 “Plastics—How to determine water absorption rate”.
Boiling water absorption rate = 100 × (m 2 −m 1 ) / m 1
However, m 1 represents the mass of the burned material of absolute dry state, m 2 represents the mass of the fired product after water absorption.
前記２価のマンガン水溶液中のマンガン濃度は、好ましくは０．１質量％以上、より好ましくは０．４質量％以上、さらに好ましくは１．０質量％以上である。該濃度が０．１質量％未満では、砒素の溶出抑制効果が十分でない場合がある。特に、水溶液のマンガンの濃度が低いと、焼成物が保持しきれずに余る水溶液の量が多くなるため、水溶液の無駄が少なくなるよう、前記（ii）の工程の場合は０．４質量％以上、（iii）の工程の場合は１.０質量％以上が好ましい。また、該濃度の上限は、２価のマンガン化合物の飽和溶解度である。
そして、２価のマンガン化合物は硫酸マンガン、硝酸マンガン、塩化マンガン、およびこれらの水和物等からなる群より選ばれる１種以上が挙げられる。これらの中でも、砒素の溶出抑制効果がより高く、取扱い性に優れ、水溶液の腐食性が低い点から硫酸マンガンが好ましく、硫酸マンガン５水和物、または硫酸マンガン１水和物がより好ましい。なお、前記２価のマンガン水溶液は、着色が問題にならない範囲で、硫酸第１鉄等の２価の鉄化合物を含んでもよい。
The manganese concentration in the divalent manganese aqueous solution is preferably 0.1% by mass or more, more preferably 0.4% by mass or more, and further preferably 1.0% by mass or more. If the concentration is less than 0.1% by mass, the arsenic elution suppression effect may not be sufficient. In particular, when the concentration of manganese in the aqueous solution is low, the amount of the aqueous solution remaining because the fired product cannot be retained increases, so that the waste of the aqueous solution is reduced, so that in the case of the step (ii) 0.4 mass% or more. In the case of the step (iii), 1.0% by mass or more is preferable. The upper limit of the concentration is the saturation solubility of the divalent manganese compound.
The divalent manganese compound includes at least one selected from the group consisting of manganese sulfate, manganese nitrate, manganese chloride, and hydrates thereof. Among these, manganese sulfate is preferable, and manganese sulfate pentahydrate or manganese sulfate monohydrate is more preferable because it has a higher arsenic elution suppression effect, excellent handleability, and low aqueous solution corrosivity. The divalent manganese aqueous solution may contain a divalent iron compound such as ferrous sulfate as long as coloring is not a problem.
また、前記焼成物中の２価のマンガンの含有量は、好ましくは焼成物１トンあたり１〜１００モルである。ただし、前記焼成物は絶乾状態である。該値が１モル未満では、砒素の溶出抑制効果が十分でない場合があり、該値が１００モルを超えると、焼成物の変色や製造装置の腐食が懸念される。なお、該値は、より好ましくは２〜５０モルである。
また、本発明が対象とする焼成物中の砒素の含有量は、特に制限はないが、好ましくは焼成物１ｋｇあたり１００ｍｇ以下である。ただし、前記焼成物は絶乾状態である。
なお、本発明の製造方法により製造された焼成物は、軽量骨材、モルタルおよびコンクリート用の細骨材および粗骨材、路盤材、路肩材、盛土材、充填材等の用途に用いることができる。特に、白色または淡色の軽量骨材等に対しては、着色が無いか少ないため、本発明の焼成物の製造方法は好適である。
Further, the content of divalent manganese in the fired product is preferably 1 to 100 mol per ton of the fired product. However, the fired product is in an absolutely dry state. If the value is less than 1 mol, the arsenic elution suppression effect may not be sufficient, and if the value exceeds 100 mol, discoloration of the fired product and corrosion of the production apparatus may occur. The value is more preferably 2 to 50 mol.
Further, the content of arsenic in the fired product targeted by the present invention is not particularly limited, but is preferably 100 mg or less per 1 kg of the fired product. However, the fired product is in an absolutely dry state.
The fired product produced by the production method of the present invention can be used for lightweight aggregates, fine aggregates and coarse aggregates for mortar and concrete, roadbed materials, road shoulder materials, embankment materials, fillers, and the like. it can. In particular, for white or light-colored lightweight aggregates and the like, since there is little or no coloration, the method for producing a fired product of the present invention is suitable.
以下、本発明を実施例により説明するが、本発明はこれらの実施例に限定されない。
１．焼成物の製造
（１）混合原料の焼成
石炭灰と未燃カーボンの合計を１００質量％とした場合に未燃カーボンを２．５質量％含む石炭灰を６８質量％、粒径が２ｍｍ以下の頁岩粉末（発泡剤）を１７質量％、および１０質量％の濃度のリグニン（粘結剤）水溶液を１５質量％混合して混合原料を作製した。
次に、該混合原料を押出し成形機を用いて成形した、直径１５ｍｍ、長さ５〜２５ｍｍの成形物を乾燥した後、該乾燥した成形物をロータリーキルンを用いて、１２００℃で３０分間、１時間あたり前記成形物を１トンの投入速度で投入して焼成し焼成物を得た。なお、該焼成物の煮沸吸水率（２時間煮沸）は２８％、絶乾密度は１．３ｇ／ｃｍ３であった。
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
1. Production of calcined product (1) Firing of mixed raw material When the total amount of coal ash and unburned carbon is 100% by mass, coal ash containing 2.5% by mass of unburned carbon is 68% by mass, and the particle size is 2 mm or less. 17% by mass of shale powder (foaming agent) and 15% by mass of an aqueous lignin (binding agent) solution having a concentration of 10% by mass were used to prepare a mixed raw material.
Next, after drying the molded product having a diameter of 15 mm and a length of 5 to 25 mm, the mixed raw material was molded using an extrusion molding machine, the dried molded product was subjected to 1 minute at 1200 ° C. for 30 minutes using a rotary kiln. The molded product was charged at a rate of 1 ton per hour and fired to obtain a fired product. In addition, the boiling water absorption (boiling for 2 hours) of the fired product was 28%, and the absolute dry density was 1.3 g / cm 3 .
（２）焼成物の浸漬（前記（ｉ）の工程）
次に、前記焼成物を空冷して２５０℃に冷えた時点で、該焼成物を２分割し、一方を硫酸マンガン５水和物として０．７５質量％の濃度の硫酸マンガン水溶液に３分間浸漬し、他方を硫酸第１鉄７水和物として０．７５質量％の濃度の硫酸第１鉄水溶液に３分間浸漬した後、該浸漬した焼成物を１２時間風乾して、２価のマンガンの含有量が焼成物１トンあたり６モルである焼成物（実施例１）、および２価の鉄の含有量が焼成物１トンあたり６モルである焼成物（比較例１）を製造した。
(2) Immersion of fired product (step (i) above)
Next, when the fired product is air-cooled and cooled to 250 ° C., the fired product is divided into two parts, and one of them is immersed in an aqueous manganese sulfate solution having a concentration of 0.75% by mass as manganese sulfate pentahydrate. And the other was immersed in a ferrous sulfate aqueous solution having a concentration of 0.75% by mass as ferrous sulfate heptahydrate for 3 minutes, and then the soaked fired product was air-dried for 12 hours, A calcined product (Example 1) having a content of 6 mol per ton of calcined product and a calcined product (Comparative Example 1) having a bivalent iron content of 6 mol per ton of calcined product were produced.
（３）焼成物に散水（（ii）の工程）
また、前記２５０℃に冷えた焼成物を２分割し、一方の焼成物に対し硫酸マンガン５水和物として１０質量％の濃度の硫酸マンガン水溶液を散水し、他方の焼成物に対し１０質量％の濃度の硫酸第１鉄水溶液を、散水量を調節して散水した後、散水処理した焼成物を１２時間風乾して、２価のマンガンの含有量が焼成物１トンあたり２モルである焼成物（実施例２）、および２価の鉄の含有量が焼成物１トンあたり２モルである焼成物（比較例２）を製造した。
（４）焼成物の浸漬後、散水（（iii）の工程）
また、前記２５０℃に冷えた焼成物を水に浸漬した後、該焼成物を風乾して表面乾燥飽水状態にした。該表面乾燥飽水状態の焼成物の含水率は２０質量％であった。
次に、該表面乾燥飽水状態の焼成物を２分割し、一方の焼成物に対し硫酸マンガン５水和物として１０質量％の濃度の硫酸マンガン水溶液を、また、他方の焼成物に対し硫酸第１鉄７水和物として１０質量％の濃度の硫酸第１鉄水溶液を、散水量を調整して散水した後、該散水した焼成物を１２時間風乾して、２価のマンガンの含有量が焼成物１トンあたり２モルである焼成物（実施例３）、および４モルである焼成物（実施例４）と、２価の鉄の含有量が焼成物１トンあたり２モルである焼成物（比較例３）、および４モルである焼成物（比較例４）を製造した。
前記と同様にして表面乾燥飽水状態にした、含水率が２０質量％の焼成物に対し、硫酸マンガン１水和物として２０質量％の濃度の硫酸マンガン水溶液を、散水量を調整して散水した後、該散水した焼成物を１２時間風乾して、２価のマンガンの含有量が焼成物１トンあたり６モルである焼成物（実施例５）を製造した。
(3) Watering the fired product (step (ii))
Further, the fired product cooled to 250 ° C. was divided into two, and a manganese sulfate aqueous solution having a concentration of 10% by mass as manganese sulfate pentahydrate was sprayed on one fired product, and 10% by mass on the other fired product. After watering the ferrous sulfate aqueous solution with a concentration of 5%, the fired product subjected to the watering treatment was air-dried for 12 hours, and the content of divalent manganese was 2 mol per ton of the fired product. Product (Example 2) and a calcined product (Comparative Example 2) in which the content of divalent iron was 2 mol per ton of calcined product.
(4) After immersion of the fired product, watering (step (iii))
The fired product cooled to 250 ° C. was immersed in water, and then the fired product was air-dried to make the surface dry and saturated. The moisture content of the surface-dried saturated water-baked product was 20% by mass.
Next, the fired product in a surface-dried saturated state is divided into two, and an aqueous manganese sulfate solution having a concentration of 10% by mass as manganese sulfate pentahydrate is added to one of the fired products, and sulfuric acid is added to the other fired product. A ferrous sulfate aqueous solution having a concentration of 10% by mass as ferrous heptahydrate was sprayed after adjusting the amount of water sprayed, and then the watered fired product was air-dried for 12 hours to contain divalent manganese. Is a baked product (Example 3) having 2 moles per ton of baked product, and a baked product (Example 4) of 4 moles, and a baked product having a divalent iron content of 2 mol per ton of baked product Product (Comparative Example 3) and a fired product (Comparative Example 4) of 4 mol were produced.
A manganese sulfate aqueous solution having a concentration of 20% by mass as manganese sulfate monohydrate was applied to the calcined product having a moisture content of 20% by mass in the same manner as described above. Then, the sprinkled fired product was air-dried for 12 hours to produce a fired product (Example 5) in which the content of divalent manganese was 6 mol per ton of the fired product.
２．焼成物からの砒素の溶出濃度の測定
前記実施例１〜５、および比較例１〜４の各焼成物５０ｇを、純水に塩酸を加えてｐＨ５．８〜６．３に調整した試験液に入れ、振とう機を用いて、２０℃、毎分２００回、および振とう幅４．５ｃｍの条件で６時間振とうした。次に、該試験液を１５分間静置した後、孔径０．４５μｍのメンブランフィルターを用いてろ過し、該ろ液中の砒素の濃度とｐＨを測定した。その結果を表１に示す。
2. Measurement of elution concentration of arsenic from calcined product 50 g of each calcined product of Examples 1 to 5 and Comparative Examples 1 to 4 was added to hydrochloric acid to pure water to adjust the pH to 5.8 to 6.3. Then, using a shaker, it was shaken for 6 hours under the conditions of 20 ° C., 200 times per minute, and a shaking width of 4.5 cm. Next, the test solution was allowed to stand for 15 minutes and then filtered using a membrane filter having a pore diameter of 0.45 μm, and the concentration and pH of arsenic in the filtrate were measured. The results are shown in Table 1.
表１に示すように、実施例１〜５は、砒素の濃度が０．０１ｍｇ／Ｌ以下で環境基準を満たす。これに対し、比較例３および比較例４は前記環境基準を満たしていない。また、実施例１は比較例１よりｐＨが高く、製造装置が腐食するおそれは低いことがわかる。
したがって、本発明の焼成物の製造方法は、砒素を含む原料を用いた場合でも、砒素の溶出を抑制した焼成物を製造でき、砒素を含む土壌、廃棄物、および天然鉱物等の有効利用を図ることができる。
As shown in Table 1, Examples 1 to 5 satisfy the environmental standard when the arsenic concentration is 0.01 mg / L or less. On the other hand, Comparative Example 3 and Comparative Example 4 do not satisfy the environmental standard. In addition, it can be seen that Example 1 has a higher pH than Comparative Example 1, and the production apparatus is less likely to corrode.
Therefore, the method for producing a baked product of the present invention can produce a baked product that suppresses arsenic elution even when a raw material containing arsenic is used, and effectively uses soil, waste, natural minerals, etc. containing arsenic. You can plan.
Claims (6)
The method for producing a fired product according to any one of claims 1 to 5, wherein the content of divalent manganese in the fired product is 1 to 100 mol per ton of the fired product.
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| JP2000506059A (en) * | 1996-02-28 | 2000-05-23 | ソルベイ（ソシエテ アノニム） | Ash inactivation method |
| JP2003080202A (en) * | 2001-09-17 | 2003-03-18 | Bogenpfeil:Kk | Method for manufacturing material for civil work and environment-construction |
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| JP2007532302A (en) * | 2004-04-14 | 2007-11-15 | ソルヴェイ（ソシエテ アノニム） | Sludge treatment method |
| JP2008049330A (en) * | 2006-07-24 | 2008-03-06 | Taiheiyo Cement Corp | Manufacturing method of fired product |
| JP2008272542A (en) * | 2006-08-03 | 2008-11-13 | Taiheiyo Cement Corp | Heavy metal elution preventing method for baked material and baked material for civil engineering material |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000506059A (en) * | 1996-02-28 | 2000-05-23 | ソルベイ（ソシエテ アノニム） | Ash inactivation method |
| JP2004511345A (en) * | 2000-10-17 | 2004-04-15 | ソルヴェイ | How to deactivate sludge |
| JP2003080202A (en) * | 2001-09-17 | 2003-03-18 | Bogenpfeil:Kk | Method for manufacturing material for civil work and environment-construction |
| JP2007532302A (en) * | 2004-04-14 | 2007-11-15 | ソルヴェイ（ソシエテ アノニム） | Sludge treatment method |
| JP2008049330A (en) * | 2006-07-24 | 2008-03-06 | Taiheiyo Cement Corp | Manufacturing method of fired product |
| JP2008272542A (en) * | 2006-08-03 | 2008-11-13 | Taiheiyo Cement Corp | Heavy metal elution preventing method for baked material and baked material for civil engineering material |
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