JP3783293B2

JP3783293B2 - Manufacturing method of water-permeable ceramic block

Info

Publication number: JP3783293B2
Application number: JP24341296A
Authority: JP
Inventors: 元木村; 光伸大谷; 重徳小松
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 1995-10-26
Filing date: 1996-09-13
Publication date: 2006-06-07
Anticipated expiration: 2016-09-13
Also published as: JPH09194268A

Description

【０００１】
【発明の属する技術分野】
本発明は、耐汚染性に優れ、かつ、比較的簡単容易に、安定して透水性セラミックスブロックを製造する方法に関する。
【０００２】
【従来の技術】
透水性セラミックスブロックの製造方法については、例えば特開昭６３−１７６３８０号公報のように、骨材とガラス質粉末を水ガラスで混合したのち一次硬化させ、焼成する方法について記載がある。この方法では混合機、焼成用セッター、サヤなどの製造ラインを著しく汚したり、ラインでの固化物が混入して収率を下げるなどの問題があった。
【０００３】
一方、特公平１−５４３１０号公報や、特公平５−５７９４号公報には、澱粉水溶液を糊剤として用いる方法が提案されている。しかしながら、澱粉水溶液を製造するには、８０〜９０℃程度に加熱しながら撹拌溶解する必要があり、工程的にも繁雑で、かつ該澱粉水溶液は、腐敗し易く、粘度などの溶液特性の経時変化が極めて著しく貯留面など工程管理上にも非常に扱いにくい問題があった。
【０００４】
【発明が解決しようとする課題】
本発明は、かかる従来技術の問題に鑑み、製造ラインを汚損せずに、しかも簡略な工程で、曲げ強度、透水係数などの特性に優れた透水性セラミックスブロックを安定して製造する方法を提供せんとするものである。
【０００５】
【課題を解決するための手段】
本発明は、かかる課題を解決するために、次のような手段を採用する。すなわち、本発明の透水性セラミックスブロックの製造方法は、ブロック全体での平均粒度が４．０ｍｍ〜１．５ｍｍの範囲にある骨材、無機バインダ、実質的にα化された澱粉粉末および水を必須成分として、骨材と実質的にα化された澱粉粉末と無機バインダとを予め実質的に乾いた状態で混合したのち水を添加して混合し、または、骨材と実質的にα化された澱粉粉末とを予め実質的に乾いた状態で混合したのち水を添加して混合して次いで無機バインダを混合し、当該混合物を加圧成型した後、乾燥固化し、次いで焼成することを特徴とするものである。
【０００６】
【発明の実施の形態】
本発明は、従来の透水性セラミックスブロックの製造方法で惹起していた、製造ラインを汚損したり、該澱粉水溶液の場合は、腐敗し易く、経時変化が極めて著しく工程管理上にも非常に扱いにくいなどの問題のない、簡単容易で綺麗に、安定して優れた物性を有するセラミックスブロックを製造できる方法を提供せんと鋭意検討したところ、有機バインダーとして特定な澱粉を採用することを究明したものである。
【０００７】
すなわち、本発明で用いる特定な澱粉は、実質的にα化されているものである。従来技術で使用されていた澱粉は、植物に由来する通常の澱粉原料、つまりβ澱粉であるため、水特に常温程度の冷水と接触しても溶解せず粘性が発現しないものであるのに対して、本発明で採用するα化された澱粉は、常温程度の冷水と接触して容易に溶解する上に、粘性が発現し接着性を発揮する特徴を有するものである。かかるα化の程度は、少なくとも５０モル％以上、好ましくは６０モル％以上、高ければ高いほうが好ましい。
【０００８】
かかるα化澱粉の分子量は、平均分子量にして３万〜５０００万程度である。３万未満では、接着力が不足する傾向があり実用的に乏しい。一方、約５０００万を越える程に高分子量となると、水への溶解性が低下し、接着作用も欠ける傾向が出てくる。
【０００９】
また、かかるα化澱粉の中でも、粘性の点からいうと、水溶液としたときの粘度が、１〜４重量％濃度で、１０〜５０００cp（２０℃）の範囲にあるものが好ましい。１０cp未満では接着作用が小さく、５０００cpを越えると粘度が高すぎて、混合状態が不均一になり焼結体の物性に悪影響を与える傾向がある。
【００１０】
かかるα化澱粉の粉末は、平均粒径としては種々のものを用いることができるが、好ましくは１〜２０μ程度のものが好適に使用される。また、かかるα化澱粉の他に、カルボキシルメチルセルロースのナトリウム塩など易水溶性の高分子物質を併用することができる。
【００１１】
本発明では、骨材、無機バインダ、実質的にα化された澱粉粉末および水を必須成分とする混合物を採用するものであるが、その混合順序は、たとえば骨材と無機バインダと実質的にα化された澱粉粉末を混合したのち水を添加するなど、混合は複数の段階にわけて、例えば二段階で行う。骨材と無機バインダと実質的にα化された澱粉粉末を均一にまぜるために予め実質的に乾いた状態で混合するのが好ましい。実質的に乾いた状態とは、骨材の種類によって、例えば火成岩質砕石のように水を含んでいる場合があるが、含水率６％以内が好ましい。その後で水を添加して澱粉粉末を溶解させ接着作用を発現せしめる。そうでないとα化された澱粉がゲル化して凝集しやすく不均一になりやすい。粉末混合手段としては公知の装置を用いる事ができる。たとえば、アイリッヒミキサー、リボンミキサー、モルタルミキサーなどを使用する。
【００１２】
別の混合順序としては、骨材と実質的にα化された澱粉粉末を予め実質的に乾いた状態で混合したのち水を添加し、ついで無機バインダを添加して混合してもよい。
【００１３】
かかる水の添加量としては、水添加後の混合物の含水率が、４〜１２重量％となるように添加する。骨材自体が予め水を含んでいる場合はその分を補正して含水率を調整する。４重量％未満では、水が混合物を形成する粒子全体にゆきわたらず、不均一となりやすく、１２重量％を越えると成型時に水が分離しやすく、この場合も不均一になり易くなる。
【００１４】
本発明の無機バインダとしては、種々のガラス例えば板ガラス、瓶ガラスなどの粉砕粉末、各種フリット粉末、釉薬粉末、ベントナイト、粘土類などを用いる。融点は、５００〜９００℃程度のものが好ましい。
【００１５】
本発明で使用する骨材の無機質粒子としては、材質的には種々のものがあるが、焼成に耐え、かつ焼成後も強度を保持させる必要があるため、例えば、鉄鋼スラグ、タイル粉砕物、碍子粉砕物、瓦粉砕物、土管粉砕物、煉瓦粉砕物、各種シャモット類、水成岩質砕石、火成岩質砕石、下水道汚泥焼却処理灰、下水道汚泥溶融スラグ、都市廃棄物焼却処理スラグ、水性堆積物焼却処理灰、水性堆積物溶融スラグなどが好ましく用いられる。
【００１６】
鉄鋼スラグの例としては、さらに徐冷スラグ、水砕スラグ、転炉スラグ、電気炉スラグなどがある。水成岩質砕石としては、例えば砂岩、シルト岩、角レキ岩、チャート、泥岩、頁岩、石灰岩などがあるがこれらに限定されるものではない。火成岩質砕石としては、例えば流紋岩、玄武岩、凝灰岩、石英粗面岩、安山岩のような火山岩そして花崗岩、閃緑岩、斑レイ岩、カンラン岩、蛇紋岩などの深成岩などがあるがこれらに限定されるものではない。下水道汚泥焼却処理灰、下水道汚泥溶融スラグは都市の下水処理場で発生する汚泥を焼却処理し有機物を分解せしめたもので、比較的粒度の細かい灰状のもの、あるいは融点以上の温度で処理して生成した溶融物を粉砕した粒状のスラグなどが用いられる。これらは処理場によって化学的な組成が変化することがあるが特に限定されるものではない。都市廃棄物焼却処理スラグは主として都市部で発生する家庭廃棄物あるいは産業廃棄物を焼却処理して発生するもので灰状のもの、溶融物を粉砕した粒状のスラグなどがある。また、水性堆積物焼却処理灰、水性堆積物溶融スラグは、例えば海洋、湖沼、河川に沈殿した堆積物を焼却して発生するもので、灰状のもの、溶融物を粉砕した粒状のスラグなどがある。
【００１７】
これら骨材を使用して製造される透水性セラミックスブロックは、一層のこともあれば二層のこともある。一層の場合、これらの骨材を１種類単独で使用して良く、あるいは数種類組み合わせブレンドして用いてもよい。さらに、二層の場合、各層が同じ骨材系でもよく、異種の組み合わせであってもよい。
【００１８】
本発明の骨材の無機質粒子は、最大粒径１０mm以内でかつ、ブロック全体での平均粒度が４．０mm〜１．５mmの範囲にある。ブロック全体での平均粒度が４．０mmを越えると焼成体の曲げ強度が低下し、１．５mm未満になると焼成体の組織が緻密化し透水性が低下するため実用性に乏しくなる。
【００１９】
あるいは本発明の製造法で得られる透水性セラミックスブロックが、二層構造を有する場合では、表層部を構成する骨材の無機質粒子は平均粒度４．０mm〜０．５mmの範囲がよい。４．０mmを越えると骨材とバインダ間の接着力が低下して骨材が欠落しやすくなる。０．５mm未満になると、表層部の組織が緻密化し透水性が低下するとともに焼成時の収縮が顕著になってひび割れが発生しやすく品位が低下する。一方、基層部を構成する骨材の無機質粒子は平均粒度４．０mm〜１．０mmの範囲がよい。平均粒度が４．０mmを越えると焼成体の曲げ強度が低下し、１．０mm未満になると焼成体の組織が緻密化し透水性が低下するので実用的でない。表層部と基層部を構成する骨材の平均粒度をこれらの範囲にし、ブロック全体では、平均粒度が４．０mm〜１．５mmの範囲にあるように調整する。
【００２０】
平均粒度の調整方法としては、例えば粒度範囲が３．５mm〜１．５mmの粗粒、粒度範囲が１．５mm〜０．５mmの中粒、粒度範囲が０．５mm以下の細粒を適当な配合比でブレンドしてもよく、あるいは粒度範囲が５mm〜２．５mmの粗粒と粒度範囲が２．５mm以下の細粒を適当な配合比でブレンドしてもよい。
【００２１】
骨材と無機バインダと実質的にα化された澱粉粉末を混合した後に水を加えてなる混合物を加圧成型して成型物を得る。加圧成型に際しては、通常の加圧プレスの他に振動式プレスを用いて成型できる。成型物の充填密度を高めるためには、振動式プレスが有効である。成型に際しては、異種の混合物原料を使用し、成型体を異種の積層構造とすることもできれば、単層にすることもできる。成形機に充填する際、一つの混合物原料を充填して、ついで別の混合物原料を充填してから、加圧成型することもできれば、一つの混合物原料を充填して、一度加圧成型したのち、ついで別の混合物原料を充填して、さらに加圧成型することもできる。
【００２２】
また、成型に際しては、種々の形状の金型を用いることによって任意の形状、任意の大きさの成型物を得ることができる。
【００２３】
かくして、成型物を公知の乾燥手段を用いて水分を蒸散せしめ、成型物にハンドリング性を付与する。乾燥手段としては、例えば、熱風式乾燥法、赤外線加熱法、マイクロ波加熱法などがある。通常、乾燥前の含水率の約半分まで乾燥すれば、機械的なハンドリング性も十分である。この乾燥固化体をついで焼成工程に供する。焼成手段としては、公知の例えば、ローラーハースキルン、シャトルキルン、トンネルキルンなどが、好ましく用いられる。焼成温度としては、骨材、無機バインダの配合組成によって異なるが、通常ピーク温度を１０００〜１２５０℃の範囲に設定し、適宜の焼成プロフィルにより透水性セラミックスブロックを得ることができる。
【００２４】
【実施例】
次に、本発明を実施例によってさらに詳細に説明する。
【００２５】
実施例１
骨材として、タイル粉砕物の３．５〜１．５mm品を８５重量部、１．５〜０．５mm品を８重量部、０．５mmアンダー品を７重量部計量した。
【００２６】
さらに板ガラス粉を１２重量部、α化澱粉粉末を０．２５重量部を計量し、モルタルミキサーに投入した。これらを乾式で混合した後、水を７重量部添加しさらに混合した。
【００２７】
この混合物を１００×２００mmサイズの金型を備えた振動式加圧プレスに充填し成型を行った。成型物を１００℃で１時間乾燥を行い、乾燥固化体を得た。ついで、この乾燥固化体を、最高温度が１１８０℃のトンネルキルンに投入して焼結して焼成体を得た。
【００２８】
この焼成体の三点曲げ強度は、６２kg／cm²、透水係数は、０．０５１cm／秒であった。実施例２
骨材として、安山岩砕石を使用し、その配合はＪＩＳＡ−５００１に定められる７号砕石とスクリーニングスをそれぞれ７０重量部と３０重量部計量したものを使用した。
【００２９】
次に、板ガラス粉を１５重量部、α化澱粉粉末を０．２５重量部を計量し、モルタルミキサーに投入した。これらを乾式で混合した後、水を８重量部添加しさらに混合した。
【００３０】
この混合物を１００×２００mmサイズの金型を備えた振動式加圧プレスに充填し成型を行った。成型物を１１０℃で１時間乾燥を行い、乾燥固化体を得た後、ついで、最高温度が１１９０℃であるトンネルキルンに投入して焼結して焼成体を得た。
【００３１】
この焼成物の三点曲げ強度は、７６kg／cm²、透水係数は、０．１２cm／秒であった。
【００３２】
実施例３
基層用原料として、骨材は、粒度範囲が３．５mm〜１．５mmの下水道汚泥溶融スラグの粗粒を６０重量部、粒度範囲が１．５mm〜０．５mmの下水道汚泥溶融スラグの中粒を３０重量部、粒度範囲が０．５mm以下の下水道汚泥焼却灰を１０重量部計量した。
【００３３】
さらに、板ガラスの粉砕品を１７重量部、α化澱粉粉末を０．２５重量部計量した。
【００３４】
これらの原料をモルタルミキサ−に投入し乾式で混合した後、水を７重量部添加しさらに混合した。（混合原料Ａとする）
表層用原料として、骨材は、粒度範囲が２．３mm〜０．５mmの碍子粉砕物を１００重量部計量した。さらに、板ガラスの粉砕品を１２重量部、α化澱粉粉末を０．２５重量部計量した。
【００３５】
これらの原料をモルタルミキサ−に投入し乾式で混合した後、水を６重量部添加しさらに混合した。（混合原料Ｂとする）
混合原料Ａを１００×２００サイズの金型を備えた振動式加圧成型機に投入し１段目の成型を行った。ついで、金型枠内上方に生じた空間に混合原料Ｂを充填し２段目の成型を行った。成型後の表層部と基層部の厚さの比率は約１：８であった。
【００３６】
この成型物を箱型乾燥機に投入し、１０５℃で約１時間処理し、乾燥固化体を得た。ついで、この乾燥固化体を最高温度が約１１９０℃のトンネルキルンに投入して焼成体を得た。
【００３７】
焼成体の三点曲げ強度は、５７kg／cm²、透水係数は、０．０６７cm／秒であった。
【００３８】
【発明の効果】
本発明によれば、混合装置、焼成用セッター、サヤを汚損することなく簡略な工程で曲げ強度、透水係数などの特性に優れたセラミックスブロックを安定して製造することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a water-permeable ceramic block which is excellent in contamination resistance and which is relatively simple, easy and stable.
[0002]
[Prior art]
As for the method for producing a water-permeable ceramic block, there is a description of a method of firstly curing and firing an aggregate and a vitreous powder with water glass as disclosed in, for example, JP-A-63-176380. This method has problems such as significantly fouling a production line such as a mixer, a setter for firing, a sheath, and a solidified product mixed in the line to lower the yield.
[0003]
On the other hand, Japanese Patent Publication No. 1-54310 and Japanese Patent Publication No. 5-5794 propose methods using an aqueous starch solution as a paste. However, in order to produce an aqueous starch solution, it is necessary to stir and dissolve while heating at about 80 to 90 ° C., which is complicated in terms of process, and the aqueous starch solution is easily spoiled, and the aging of solution characteristics such as viscosity There was a problem that the change was extremely remarkable and it was very difficult to handle the process management such as the storage surface.
[0004]
[Problems to be solved by the invention]
The present invention provides a method for stably producing a water-permeable ceramic block excellent in characteristics such as bending strength and water permeability in a simple process without fouling the production line. It is something to be done.
[0005]
[Means for Solving the Problems]
The present invention employs the following means in order to solve such problems. That is, the method for producing a water-permeable ceramic block of the present invention comprises an aggregate, an inorganic binder, a substantially pregelatinized starch powder and water having an average particle size in the range of 4.0 mm to 1.5 mm. As an essential component, the aggregate, the substantially pregelatinized starch powder, and the inorganic binder are mixed in advance in a substantially dry state and then mixed with water, or the aggregate and the aggregate are substantially pregelatinized. The starch powder thus prepared is mixed in advance in a substantially dry state, then water is added and mixed, then the inorganic binder is mixed, the mixture is pressure-molded, dried and solidified, and then fired. It is a feature.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is caused by the conventional method for producing a water-permeable ceramic block, which fouls the production line, and in the case of the starch aqueous solution, it easily perishes, and the change with time is extremely significant, which is very handled in process control. We have eagerly studied to provide a method that can produce ceramic blocks that are easy, easy, clean, stable, and have excellent physical properties without problems such as difficulties, and have found that a specific starch is used as the organic binder. It is.
[0007]
That is, the specific starch used in the present invention is substantially pregelatinized. The starch used in the prior art is an ordinary starch raw material derived from plants, that is, β starch, so that it does not dissolve and does not develop viscosity even when contacted with water, particularly cold water at room temperature. In addition, the pregelatinized starch employed in the present invention has characteristics that it is easily dissolved in contact with cold water at about room temperature and exhibits viscosity and exhibits adhesiveness. The degree of such pregelatinization is preferably at least 50 mol% or more, preferably 60 mol% or more, and the higher the higher.
[0008]
The molecular weight of such pregelatinized starch is about 30,000 to 50 million in terms of average molecular weight. If it is less than 30,000, the adhesive strength tends to be insufficient, which is practically poor. On the other hand, when the molecular weight is higher than about 50 million, the solubility in water is lowered and the adhesive action tends to be lacking.
[0009]
Among such pregelatinized starches, in terms of viscosity, those having an aqueous solution concentration of 1 to 4% by weight and having a concentration in the range of 10 to 5000 cp (20 ° C.) are preferable. If it is less than 10 cp, the adhesive action is small, and if it exceeds 5000 cp, the viscosity is too high and the mixed state becomes non-uniform and the physical properties of the sintered body tend to be adversely affected.
[0010]
Various powders of such pregelatinized starch can be used as the average particle diameter, but those having a particle size of about 1 to 20 μm are preferably used. In addition to the pregelatinized starch, a water-soluble polymer substance such as sodium salt of carboxymethyl cellulose can be used in combination.
[0011]
In the present invention, a mixture comprising an aggregate, an inorganic binder, a substantially pregelatinized starch powder, and water as essential components is employed. The order of mixing is substantially, for example, the aggregate and the inorganic binder. The mixing is performed in a plurality of stages, for example, in two stages, such as adding water after adding the pregelatinized starch powder. In order to uniformly mix the aggregate, the inorganic binder, and the substantially pregelatinized starch powder, it is preferably mixed in advance in a substantially dry state. The substantially dry state may contain water, such as igneous crushed stone, depending on the type of aggregate, but a water content of 6% or less is preferable. Thereafter, water is added to dissolve the starch powder to develop an adhesive action. Otherwise, the pregelatinized starch will gel and tend to aggregate and become non-uniform. As the powder mixing means, a known apparatus can be used. For example, an Eirich mixer, a ribbon mixer, a mortar mixer or the like is used.
[0012]
As another mixing sequence, the aggregate and the substantially pregelatinized starch powder may be mixed in advance in a substantially dry state, and then water may be added, and then an inorganic binder may be added and mixed.
[0013]
The amount of water added is such that the water content of the mixture after water addition is 4 to 12% by weight. When the aggregate itself contains water in advance, the water content is adjusted by correcting that amount. If it is less than 4% by weight, water does not spread over the entire particles forming the mixture and tends to be non-uniform, while if it exceeds 12% by weight, water tends to separate during molding, and in this case also tends to be non-uniform.
[0014]
As the inorganic binder of the present invention, various kinds of glass such as pulverized powders such as plate glass and bottle glass, various frit powders, glaze powders, bentonite, clays and the like are used. The melting point is preferably about 500 to 900 ° C.
[0015]
As the inorganic particles of the aggregate used in the present invention, there are various materials, but it is necessary to withstand firing and maintain strength even after firing.For example, steel slag, tile pulverized material, Palm ground, tile ground, clay pipe ground, brick ground, various chamottes, aquatic rocks, igneous rocks, sewer sludge incineration ash, sewer sludge melting slag, municipal waste incineration slag, aqueous sediment incineration Treated ash, aqueous sediment molten slag, and the like are preferably used.
[0016]
As examples of steel slag, there are further annealed slag, granulated slag, converter slag, electric furnace slag, and the like. Examples of hydrolithic crushed stones include, but are not limited to, sandstone, siltstone, hornstone, chert, mudstone, shale, and limestone. Examples of igneous rocks include volcanic rocks such as rhyolite, basalt, tuff, quartz granite, andesite, and plutonic rocks such as granite, diorite, gabbro, peridotite, and serpentinite. Is not to be done. Sewage sludge incineration ash and sewage sludge molten slag are incinerated sludge generated in urban sewage treatment plants to decompose organic matter, and processed at a relatively fine grained ash or at a temperature above the melting point. A granular slag obtained by pulverizing the melt produced in this manner is used. The chemical composition of these may vary depending on the treatment site, but is not particularly limited. Municipal waste incineration slag is mainly generated by incineration of household waste or industrial waste generated in urban areas, and includes ash-like and granular slag obtained by pulverizing melt. Aqueous sediment incineration ash and aqueous sediment molten slag are generated by incineration of sediment deposited in the ocean, lakes, rivers, etc., and are ash-like, granular slag obtained by pulverizing the melt, etc. There is.
[0017]
The water-permeable ceramic block manufactured using these aggregates may be one layer or two layers. In the case of one layer, these aggregates may be used alone or in combination of several kinds. Further, in the case of two layers, each layer may be the same aggregate system or a different combination.
[0018]
The aggregated inorganic particles of the present invention have a maximum particle size of 10 mm or less and an average particle size of the whole block in the range of 4.0 mm to 1.5 mm. When the average particle size of the whole block exceeds 4.0 mm, the bending strength of the fired body is lowered, and when it is less than 1.5 mm, the structure of the fired body becomes dense and the water permeability is lowered, so that the practicality becomes poor.
[0019]
Alternatively, when the water-permeable ceramic block obtained by the production method of the present invention has a two-layer structure, the aggregate inorganic particles constituting the surface layer portion preferably have an average particle size of 4.0 mm to 0.5 mm. If it exceeds 4.0 mm, the adhesive force between the aggregate and the binder is reduced, and the aggregate is likely to be lost. If the thickness is less than 0.5 mm, the structure of the surface layer portion becomes dense and water permeability is lowered, and shrinkage during firing becomes remarkable, and cracks are likely to occur and the quality is lowered. On the other hand, the inorganic particles of the aggregate constituting the base layer portion preferably have an average particle size of 4.0 mm to 1.0 mm. When the average particle size exceeds 4.0 mm, the bending strength of the fired body is lowered, and when it is less than 1.0 mm, the structure of the fired body becomes dense and the water permeability is lowered, which is not practical. The average particle size of the aggregate constituting the surface layer portion and the base layer portion is set within these ranges, and the entire particle size is adjusted so that the average particle size is in the range of 4.0 mm to 1.5 mm.
[0020]
As a method for adjusting the average particle size, for example, coarse particles having a particle size range of 3.5 mm to 1.5 mm, medium particles having a particle size range of 1.5 mm to 0.5 mm, and fine particles having a particle size range of 0.5 mm or less are suitable. You may blend by a compounding ratio, or you may blend the coarse particle of a particle size range of 5 mm-2.5 mm, and the fine particle of a particle size range of 2.5 mm or less by a suitable compounding ratio.
[0021]
After the aggregate, the inorganic binder, and the substantially pregelatinized starch powder are mixed, a mixture obtained by adding water is pressure-molded to obtain a molded product. In press molding, it can be molded using a vibration press in addition to a normal press. In order to increase the filling density of the molded product, a vibrating press is effective. In molding, different mixture raw materials can be used, and the molded body can have a different laminated structure or a single layer. When filling the molding machine, it is possible to fill one mixture raw material, then fill another mixture raw material, and then press-mold, or after filling one mixture raw material and press-molding once Then, another mixture raw material can be filled and further pressure-molded.
[0022]
In molding, a molded product having any shape and any size can be obtained by using molds having various shapes.
[0023]
Thus, moisture is evaporated from the molded product using a known drying means, and handling properties are imparted to the molded product. Examples of the drying means include a hot air drying method, an infrared heating method, and a microwave heating method. Usually, if it is dried to about half of the moisture content before drying, the mechanical handleability is sufficient. This dried solidified body is then subjected to a firing step. As the firing means, for example, a known roller hearth kiln, shuttle kiln, tunnel kiln or the like is preferably used. Although the firing temperature varies depending on the composition of the aggregate and the inorganic binder, the peak temperature is usually set in a range of 1000 to 1250 ° C., and a water-permeable ceramic block can be obtained by an appropriate firing profile.
[0024]
【Example】
Next, the present invention will be described in further detail with reference to examples.
[0025]
Example 1
As aggregate, 85 parts by weight of 3.5 to 1.5 mm of crushed tile, 8 parts by weight of 1.5 to 0.5 mm, and 7 parts by weight of 0.5 mm under goods were weighed.
[0026]
Further, 12 parts by weight of plate glass powder and 0.25 parts by weight of pregelatinized starch powder were weighed and put into a mortar mixer. After these were mixed by a dry method, 7 parts by weight of water was added and further mixed.
[0027]
This mixture was filled in a vibrating pressure press equipped with a 100 × 200 mm size mold and molded. The molded product was dried at 100 ° C. for 1 hour to obtain a dried and solidified product. Next, this dried solidified body was put into a tunnel kiln having a maximum temperature of 1180 ° C. and sintered to obtain a fired body.
[0028]
This fired body had a three-point bending strength of 62 kg / cm ² and a water permeability of 0.051 cm / second. Example 2
As the aggregate, andesite crushed stone was used, and its blend was measured by measuring 70 parts by weight and 30 parts by weight of No. 7 crushed stone defined in JIS A-5001 and screenings, respectively.
[0029]
Next, 15 parts by weight of plate glass powder and 0.25 parts by weight of pregelatinized starch powder were weighed and put into a mortar mixer. After these were mixed by a dry method, 8 parts by weight of water was added and further mixed.
[0030]
This mixture was filled in a vibrating pressure press equipped with a 100 × 200 mm size mold and molded. The molded product was dried at 110 ° C. for 1 hour to obtain a dried and solidified body, and then put into a tunnel kiln having a maximum temperature of 1190 ° C. and sintered to obtain a fired body.
[0031]
This fired product had a three-point bending strength of 76 kg / cm ² and a water permeability of 0.12 cm / second.
[0032]
Example 3
As raw material for the base layer, the aggregate is 60 parts by weight of coarse particles of sewage sludge molten slag having a particle size range of 3.5 mm to 1.5 mm and medium particles of sewage sludge molten slag having a particle size range of 1.5 mm to 0.5 mm. 30 parts by weight, and 10 parts by weight of sewer sludge incinerated ash having a particle size range of 0.5 mm or less.
[0033]
Further, 17 parts by weight of the pulverized plate glass and 0.25 parts by weight of the pregelatinized starch powder were weighed.
[0034]
After these raw materials were put into a mortar mixer and mixed by dry method, 7 parts by weight of water was added and further mixed. (Mixed raw material A)
As a raw material for the surface layer, 100 parts by weight of aggregated pulverized material having a particle size range of 2.3 mm to 0.5 mm was weighed. Further, 12 parts by weight of the pulverized plate glass and 0.25 parts by weight of the pregelatinized starch powder were weighed.
[0035]
After these raw materials were put into a mortar mixer and mixed by dry method, 6 parts by weight of water was added and further mixed. (Mixed raw material B)
The mixed raw material A was put into a vibration pressure molding machine equipped with a 100 × 200 size mold, and the first stage molding was performed. Subsequently, the mixed raw material B was filled in the space formed above the inside of the mold frame, and the second stage molding was performed. The ratio of the thickness of the surface layer portion and the base layer portion after molding was about 1: 8.
[0036]
This molded product was put into a box-type dryer and treated at 105 ° C. for about 1 hour to obtain a dried solidified product. Subsequently, this dried solidified body was put into a tunnel kiln having a maximum temperature of about 1190 ° C. to obtain a fired body.
[0037]
The three-point bending strength of the fired body was 57 kg / cm ² , and the water permeability was 0.067 cm / sec.
[0038]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the ceramic block excellent in characteristics, such as bending strength and a water permeability, can be stably manufactured in a simple process, without fouling a mixing apparatus, a setter for baking, and a sheath.

Claims

Aggregated with an aggregate having an average particle size in the range of 4.0 mm to 1.5 mm, an inorganic binder, a substantially pregelatinized starch powder, and water as essential components. The starch powder and the inorganic binder are mixed in advance in a substantially dry state and then mixed with water, or the aggregate and the substantially pregelatinized starch powder are in a substantially dry state in advance. A method for producing a water-permeable ceramic block, comprising adding water, mixing and then mixing an inorganic binder, press-molding the mixture, drying and solidifying, and then firing.

The method for producing a water-permeable ceramic block according to claim 1, wherein the pregelatinized starch powder is soluble in cold water.

The method for producing a water-permeable ceramic block according to claim 1, wherein the pregelatinized starch powder has an average molecular weight of 30,000 to 50 million.

The method for producing a water-permeable ceramic block according to claim 1, wherein the gelatinized starch powder has a 1 to 4 wt% aqueous solution having a viscosity of 10 to 5000 cp at 20 ° C.

The method for producing a water-permeable ceramic block according to claim 1, wherein the inorganic binder is glass powder, frit, glaze, or clay.

The method for producing a water-permeable ceramic block according to claim 1, wherein the pressure molding is vibration type pressure molding.

The method for producing a water-permeable ceramic block according to claim 1, wherein the aggregate constituting the water-permeable ceramic block is an inorganic particle having a maximum particle size of 10 mm or less.

The water-permeable ceramic block has a two-layer structure, the aggregate constituting the surface layer portion is inorganic particles having an average particle size in the range of 4.0 mm to 0.5 mm, and the aggregate constituting the base layer portion is the average particle size The method for producing a water-permeable ceramic block according to claim 1, wherein the particles are inorganic particles in a range of 4.0 mm to 1.0 mm.

The inorganic particles are steel slag, tile pulverized material, insulator pulverized material, tile pulverized material, clay pipe pulverized material, brick pulverized material, various chamottes, hydrolithic crushed stone, igneous rock crushed stone, sewer sludge incineration ash, sewer sludge molten slag. The method for producing a water-permeable ceramic block according to claim 7 or 8 , which is at least one selected from municipal waste incineration slag, aqueous sediment incineration ash, and aqueous sediment molten slag.

The method for producing a water-permeable ceramic block according to claim 1, wherein the amount of water added is such that the water content of the mixture after water addition is 4 to 12% by weight.