JP3653300B2

JP3653300B2 - Artificial aggregate and method for producing the same

Info

Publication number: JP3653300B2
Application number: JP5194595A
Authority: JP
Inventors: 悟藤井; 正明野村
Original assignee: Taiheiyo Cement Corp
Current assignee: Taiheiyo Cement Corp
Priority date: 1995-02-16
Filing date: 1995-02-16
Publication date: 2005-05-25
Anticipated expiration: 2020-05-25
Also published as: JPH08217501A

Description

【０００１】
【産業上の利用分野】
この発明は、都市ゴミ焼却灰、下水汚泥焼却灰を利用した人工骨材及びその製造方法に関するものである。
【０００２】
【従来の技術】
従来、都市ゴミ焼却灰及び下水汚泥焼却灰は、大部分が埋立て処理され、埋立地は健康に係わる重金属等の有害物が溶出するため要管理地となっている。また、近年の焼却灰の発生量増大から十分な埋立地の確保が困難になりつつあり、将来の灰処理が危惧されている。
【０００３】
一方、埋立地の延命策として、焼却灰の容量を縮小させると共に含有する重金属の溶出を抑制するために溶融化処理が提案されている。しかしながら、この方法はエネルギーコストが高い上にメンテナンスに難があり、しかも、溶融灰の有効利用が十分に果たせないのが現状である。従って、この方法で焼却灰を減容化することは、ある程度の埋立地の延命策となるものの、根本的な解決策とはならず、焼却灰をリサイクル資源として活用することが大きな社会的ニーズとなっている。
【０００４】
【発明が解決しようとする課題】
この発明は、このような事情に鑑みなされたもので、都市ゴミ焼却灰及び下水汚泥焼却灰の有害物質を固定化させ、モルタル、コンクリート、アスファルト用の骨材、埋め戻し材、路盤材、敷材等として大量に有効利用することができる人工骨材及びその製造方法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
前記目的を達成するために、この発明の人工骨材によれば、都市ゴミ焼却灰及び／又は下水汚泥焼却灰と、生石灰、消石灰、及び炭酸化カルシウムの群から選択される少なくとも一種と、蛍石とを、主要成分として焼成してなる人工骨材であって、都市ゴミ焼却灰及び／又は下水汚泥焼却灰と、生石灰、消石灰、及び炭酸化カルシウムの群から選択される少なくとも一種と蛍石との合量が重量比で７０〜４０：３０〜６０、生石灰、消石灰、及び炭酸化カルシウムの群から選択される少なくとも一種と、蛍石が重量比で９０〜５０：１０〜５０であること（請求項１）、を特徴とし、またこの発明の人工骨材の製造方法によれば、都市ゴミ焼却灰及び／又は下水汚泥焼却灰と、生石灰、消石灰、及び炭酸化カルシウムの群から選択される少なくとも一種と、蛍石とを、主要成分として造粒し、９００℃〜１２００℃の温度で焼成すること（請求項２）、都市ゴミ焼却灰及び／又は下水汚泥焼却灰と、生石灰、消石灰、及び炭酸化カルシウムの群から選択される少なくとも一種と蛍石との合量が重量比で７０〜４０：３０〜６０であること（請求項３）、生石灰、消石灰、及び炭酸化カルシウムの群から選択される少なくとも一種と、蛍石が重量比で９０〜５０：１０〜５０であること（請求項４）、を特徴とする。以下、この発明を詳細に説明する。
【０００６】
この発明で使用する都市ゴミ焼却灰及び下水汚泥焼却灰（以下、焼却灰という）は、自治体等での都市ゴミや下水汚泥の焼却処分によって排出される焼却灰をそのまま、あるいは粉砕して使用する。粉砕は、焼却灰単独、あるいは、後述する混合材との混合粉砕でも良く、使用に当たっては、ブレーン比表面積２０００ｃｍ² ／ｇ以上とすることが望ましい。この焼却灰は、発生場所や焼却設備の種類等により化学成分値が大幅に異なるものの、ＣａＯ、ＳｉＯ₂ 、Ａｌ₂ Ｏ₃ 等、骨材として有効な成分が多く、また、若干量のカドミウム、鉛、水銀、クロム等の重金属を含有していることが多い。焼却灰の組成例を表１に示す。
【０００７】
【表１】

【０００８】
この焼却灰を用いて前述したコンクリート用骨材等各種の骨材を製造するに当たり、骨材は、堅牢且つ給水率が低いことが必須の条件であり、また、重金属の溶出がなく化学的に安定であることが要求される。市販されている膨張頁岩やフライアッシュを用いて製造される人工骨材と同様に、焼却灰をそのまま、あるいは、粉砕後ベントナイト（造粒助材）を添加して造粒後、焼成して得られる骨材は、都市ゴミ焼却灰を例にすると、図１及び図２に示すように焼成温度の上昇と共に比重が小さくなり軽量化する。しかし、この焼成物は吸水率が２０％程度と高い上、水中で長期保存すると崩壊するため前述した骨材としての使用が不可能である。
【０００９】
この発明は、焼却灰に混合材として生石灰、消石灰、及び炭酸化カルシウムの群から選択される少なくとも一種（以下、石灰等という）と、蛍石とを併用使用することにより、高比重、低吸水率で有害物の溶出がなく、普通骨材と遜色のない安定した骨材とする。
【００１０】
焼却灰、石灰等、及び蛍石の使用割合は、焼却灰を７０〜４０重量部、混合材（石灰等と蛍石の合計量）を３０〜６０重量部とし、混合材は石灰等を９０〜５０重量部、蛍石を１０〜５０重量部の範囲とする。混合材が３０重量部より少ないと、焼成温度を高くしても比重が大きくならず、しかも吸水率も高く重金属等の溶出が見られるなど好ましくない。また、これを６０重量部を超えて混合することは、良質な骨材が得られるものの、焼却灰の使用量が少なくなり、焼却灰を大量に有効利用する発明の目的にそぐわないばかりか、コスト高となり不経済である。
【００１１】
混合材中の蛍石の使用は、石灰等との併用使用と相俟って、焼成温度を下げ、高比重、低給水率の骨材として安定した共有物を形成する、蛍石と石灰等の使用比率において、蛍石が１０重量部より少ないと、焼成温度低減効果を含めて、前記優れた骨材とすることができず、また、５０重量部を超えて使用しても、骨材としての特性が向上する以上にコスト高になるほか、過剰使用は、かえって前記骨材としての特性が低下して好ましくない。混合材は、ブレーン比表面積２０００ｃｍ² ／ｇ以上、好ましくは、４０００〜１５０００ｃｍ² ／ｇ程度の物が好適に用いられ、混合材をそれぞれ単独、若しくは混合粉砕、あるいは焼却灰と混合粉砕して粒度を調整することができる。
【００１２】
上記した焼却灰及び混合材に、造粒助材、及び水を適量加えて造粒し、５〜１５ｍｍ程度の焼成用ペレットを製造する。造粒は、加圧成形、押出し成形、転動造粒等、各種の造粒法が適用でき、特に成形の容易さからパンペレタイザーが好適に用いられる。造粒助材としては、ベントナイトが好適に使用でき、これを焼却灰及び混合材１００重量部に対して１０重量部以内、また、水を２０重量部以内で添加して造粒する。
【００１３】
次に、ペレットを焼成してこの発明の人工骨材を得る。焼成は、ロータリキルン、竪窯、移動火格子形炉等、各種の焼成炉を用い、９００〜１２００℃、好ましくは、９５０〜１１００℃の温度範囲とすることにより、比重２．０以上の高比重、低吸水率で高強度の良質な骨材とすることができる。焼成温度は、ペレット中に占める混合材の添加量にもよるが、９００℃未満では比重、吸水率、及び強度の点で不十分であり、また、１２００℃を越えて焼成しても、比重、吸水率等が頭打ちとなり、経済的でない。
【００１４】
【作用】
この発明によれば、焼成を容易にし、焼却灰中の有害物を溶出することなく、普通骨材と遜色のない比重、吸水率等の物性を有する堅牢な骨材とすることができ、モルタル、コンクリート、アスファルト用の骨材、埋め戻し材、路盤材、敷材等として大量に有効利用することができる。
【００１５】
【実施例】
表１に示す組成の都市ゴミ焼却灰、及び下水汚泥焼却灰を粉砕してそれぞれブレーン比表面積３１００ｃｍ² ／ｇ、及び３２００ｃｍ² ／ｇとした焼却灰に、ブレーン比表面積がそれぞれ５１００ｃｍ² ／ｇの蛍石、８５００ｃｍ² ／ｇの消石灰、８０００ｃｍ² ／ｇの生石灰、及び、９０００ｃｍ² ／ｇとした炭酸カルシウムを表２に示す各種の配合割合で添加し、これに増粘材としてベントナイト５重量部を加え、十分に混合した後、直径１ｍのパンペレタイザーに水を添加しながら５〜１０ｍｍ径のペレットに造粒した。造粒物を直径４５０ｍｍ、長さ８２７０ｍｍのロータリキルンに１５０Ｋｇ／ｈの割合で送入し、各種の温度で焼成した。結果を表２に示す。この発明の骨材は、比重２．０以上で低吸水率の優れた骨材が得られた。
【００１６】
【表２】

【００１７】
次に、表２で得られた骨材の「産業廃棄物に含まれる金属等の検定方法（溶出試験）（昭和４８年２月１７日、環境庁告示第１３号）に準拠した溶出試験を行った。この発明の骨材は、いずれも有害物質が検出限界以下に固定され、溶出が起らなかった。一例として表２、ＮＯ１５の試験結果を表３に示す。
【００１８】
【表３】

【００１９】
【発明の効果】
この発明によれば、都市ゴミ焼却灰及び下水汚泥焼却灰を骨材として活用することにより、有害物質を溶出することなく安定して焼却灰を大量に資源化することができる。
【図面の簡単な説明】
【図１】この発明によらない焼成温度と焼成物の比重の関係を示す図である。
【図２】この発明によらない焼成温度と焼成物の吸水率の関係を示す図である。[0001]
[Industrial application fields]
The present invention relates to an artificial aggregate using municipal waste incineration ash and sewage sludge incineration ash and a method for producing the same.
[0002]
[Prior art]
Conventionally, most municipal waste incineration ash and sewage sludge incineration ash are landfilled, and the landfill site has become a required management site because harmful substances such as heavy metals related to health are eluted. In addition, it is becoming difficult to secure a sufficient landfill due to an increase in the amount of incinerated ash generated in recent years, and future ash treatment is feared.
[0003]
On the other hand, as a life prolonging measure for landfill sites, a melting process has been proposed in order to reduce the volume of incinerated ash and suppress elution of contained heavy metals. However, this method has a high energy cost and is difficult to maintain, and the effective use of molten ash cannot be sufficiently achieved. Therefore, while reducing the volume of incinerated ash by this method is a measure to prolong the life of landfills to some extent, it is not a fundamental solution, and it is a great social need to use incinerated ash as a recycling resource. It has become.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and fixes harmful substances such as municipal waste incineration ash and sewage sludge incineration ash to fix mortar, concrete, aggregate for asphalt, backfill material, roadbed material, flooring. An object of the present invention is to provide an artificial aggregate that can be effectively used in large quantities as a material and the like, and a method for producing the same.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the artificial aggregate of the present invention, at least one selected from the group of municipal waste incineration ash and / or sewage sludge incineration ash, quick lime, slaked lime, and calcium carbonate, and firefly Artificial aggregate obtained by firing stone as a main component , and at least one selected from the group of municipal waste incineration ash and / or sewage sludge incineration ash, quicklime, slaked lime, and calcium carbonate and fluorite And the total amount is 70-40: 30-60 by weight ratio, The artificial bone of the present invention is characterized in that at least one selected from the group consisting of quicklime, slaked lime, and calcium carbonate and fluorite is 90 to 50:10 to 50 by weight ratio (Claim 1). According to the method for producing wood, granulation is carried out by granulating municipal waste incineration ash and / or sewage sludge incineration ash, at least one selected from the group of quick lime, slaked lime, and calcium carbonate, and fluorite. Calcination at a temperature of 900 ° C. to 1200 ° C. (Claim 2) , at least one selected from the group of municipal waste incineration ash and / or sewage sludge incineration ash, quicklime, slaked lime, and calcium carbonate and fluorite And the total amount of calcite is 70 to 40:30 to 60 by weight (Claim 3) , at least one selected from the group of quicklime, slaked lime, and calcium carbonate, and fluorite is 90 to 90 by weight. 50: It is 0 to 50 (claim 4), characterized by. Hereinafter, the present invention will be described in detail.
[0006]
The municipal waste incineration ash and sewage sludge incineration ash (hereinafter referred to as incineration ash) used in the present invention is used as it is or after pulverizing the incineration ash discharged by the municipal waste and the sewage sludge incineration disposal in the local government. . The pulverization may be incineration ash alone or mixed pulverization with a mixture material described later. In use, it is desirable that the specific surface area of the brain is 2000 cm ² / g or more. This incineration ash has many components that are effective as aggregates, such as CaO, SiO ₂ , Al ₂ O _3, etc., although the chemical component values vary greatly depending on the location of the incineration and the type of incineration equipment, etc., and a small amount of cadmium, It often contains heavy metals such as lead, mercury and chromium. A composition example of incineration ash is shown in Table 1.
[0007]
[Table 1]

[0008]
In producing various aggregates such as the above-mentioned concrete aggregates using this incinerated ash, it is essential that the aggregates be robust and have a low water supply rate. It is required to be stable. As with artificial aggregates manufactured using commercially available expanded shale and fly ash, incinerated ash is used as it is, or after pulverized bentonite (granulation aid) is added, granulated, and then fired. Taking municipal waste incineration ash as an example, the aggregate is reduced in specific gravity and weight as the firing temperature is increased, as shown in FIGS. However, this fired product has a high water absorption rate of about 20% and disintegrates when stored for a long time in water, so it cannot be used as the above-mentioned aggregate.
[0009]
This invention uses high specific gravity and low water absorption by using incinerated ash in combination with at least one selected from the group of quick lime, slaked lime, and calcium carbonate (hereinafter referred to as lime) and fluorite. A stable aggregate that is free from harmful substances and is comparable to ordinary aggregate.
[0010]
The incinerated ash, lime, etc. and fluorite are used in a proportion of 70-40 parts by weight of incinerated ash, 30-60 parts by weight of the mixed material (total amount of lime, etc. and fluorite), and 90% by weight of the mixed material. -50 parts by weight and fluorite in the range of 10-50 parts by weight. When the amount of the mixed material is less than 30 parts by weight, the specific gravity does not increase even when the firing temperature is increased, and the water absorption rate is also high and elution of heavy metals and the like is not preferable. In addition, mixing more than 60 parts by weight is not only suitable for the purpose of the invention to effectively use a large amount of incineration ash, although the amount of incineration ash used is reduced, although a good quality aggregate is obtained. High and uneconomical.
[0011]
The use of fluorite in the mixed material, combined with the combined use with lime, etc., lowers the firing temperature and forms a stable common material as an aggregate with high specific gravity and low water supply rate, fluorite and lime, etc. If the amount of fluorite is less than 10 parts by weight, the above-mentioned excellent aggregate cannot be obtained, including the effect of reducing the firing temperature, and even if it exceeds 50 parts by weight, the aggregate In addition to the improvement of the characteristics of the above, the cost becomes higher and the excessive use is not preferable because the characteristics of the aggregate are deteriorated. Mixing material, Blaine specific surface area of 2000 cm ² / g or more, preferably, 4000~15000cm ² / g approximately ones are preferably used, the mixed material alone, or mixed grinding, or ash and then mixed and ground particle size Can be adjusted.
[0012]
Appropriate amounts of granulation aid and water are added to the above incinerated ash and mixed material, and granulated to produce pellets for firing of about 5 to 15 mm. For granulation, various granulation methods such as pressure molding, extrusion molding, rolling granulation, and the like can be applied. In particular, a pan pelletizer is preferably used because of easy molding. Bentonite can be suitably used as the granulating aid, and this is granulated by adding water within 10 parts by weight and water within 20 parts by weight with respect to 100 parts by weight of incinerated ash and mixed material.
[0013]
Next, the pellet is fired to obtain the artificial aggregate of the present invention. Firing is performed at a temperature range of 900 to 1200 ° C., preferably 950 to 1100 ° C., using a variety of firing furnaces such as a rotary kiln, wood kiln, and moving grate furnace. A high-quality aggregate with high specific gravity and low water absorption can be obtained. Although the firing temperature depends on the added amount of the mixed material in the pellets, if it is less than 900 ° C., it is insufficient in terms of specific gravity, water absorption, and strength. The water absorption rate has reached its peak and is not economical.
[0014]
[Action]
According to the present invention, it is possible to make a solid aggregate that has physical properties such as specific gravity and water absorption comparable to ordinary aggregates without facilitating firing and eluting harmful substances in the incinerated ash. It can be effectively used in large quantities as concrete, asphalt aggregate, backfill material, roadbed material, flooring material, and the like.
[0015]
【Example】
Municipal waste incineration ash having the composition shown in Table 1, and respectively the Blaine specific by grinding sludge incineration ash surface area 3100 cm ² / g, and the incineration ash was 3200 cm ² / g, the Blaine specific surface area of 5100cm ² / g, respectively Fluorite, 8500 cm ² / g slaked lime, 8000 cm ² / g quicklime, and 9000 cm ² / g calcium carbonate were added at various blending ratios shown in Table 2, and 5 parts by weight of bentonite as a thickener Was added and mixed well, and the mixture was granulated into pellets having a diameter of 5 to 10 mm while adding water to a pan pelletizer having a diameter of 1 m. The granulated product was fed into a rotary kiln having a diameter of 450 mm and a length of 8270 mm at a rate of 150 kg / h, and fired at various temperatures. The results are shown in Table 2. The aggregate of the present invention was an aggregate having a specific gravity of 2.0 or more and an excellent low water absorption rate.
[0016]
[Table 2]

[0017]
Next, the dissolution test in accordance with the “Analysis method (dissolution test) of metals contained in industrial waste” (February 17, 1973, Environmental Agency Notification No. 13) of aggregates obtained in Table 2 In the aggregates of the present invention, no harmful substances were fixed below the detection limit and no elution occurred.Table 2 shows the test results of NO15 and Table 3 shows the test results of NO15.
[0018]
[Table 3]

[0019]
【The invention's effect】
According to the present invention, by utilizing municipal waste incineration ash and sewage sludge incineration ash as aggregates, it is possible to stably incinerate incineration ash in a large amount without eluting harmful substances.
[Brief description of the drawings]
FIG. 1 is a diagram showing the relationship between the firing temperature and the specific gravity of a fired product not according to the present invention.
FIG. 2 is a diagram showing a relationship between a firing temperature and a water absorption rate of a fired product not according to the present invention.

Claims

Municipal waste incineration ash and / or sewage sludge incineration ash, at least one selected from the group of quicklime, slaked lime, and calcium carbonate, and an artificial aggregate formed by firing fluorite as main components , The total amount of at least one selected from the group of municipal waste incineration ash and / or sewage sludge incineration ash, quicklime, slaked lime, and calcium carbonate and fluorite is 70 to 40:30 to 60 by weight ratio, An artificial bone material characterized in that at least one selected from the group of quicklime, slaked lime, and calcium carbonate and fluorite are 90 to 50:10 to 50 in a weight ratio.

A municipal waste incineration ash and / or sewage sludge incineration ash, at least one selected from the group of quicklime, slaked lime, and calcium carbonate, and fluorite are granulated as main components, and a temperature of 900 ° C. to 1200 ° C. A method for producing an artificial aggregate, characterized in that it is fired.

The total amount of at least one selected from the group of municipal waste incineration ash and / or sewage sludge incineration ash, quicklime, slaked lime, and calcium carbonate and fluorite is 70 to 40:30 to 60 by weight. The method for producing an artificial aggregate according to claim 2 .

The method for producing an artificial bone according to claim 3 , wherein the weight ratio of at least one selected from the group of quicklime, slaked lime, and calcium carbonate and fluorite is 90-50: 10-50.