JP2004059370A - Method for kneading castable refractory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a kneading method for a castable refractory which eliminates the deterioration of workability of a castable refractory containing a recycled material by a simple means and gives a construction body more compact, more excellent in corrosion resistance and strength than a conventional one. <P>SOLUTION: This kneading method for a castable refractory uses a recycled material as at least a part of a refractory raw material. The recycled material is a water absorption-treated one, has a water absorption of 2% or more and a water absorption index shown by formula (1) of 10-100, and is used in an amount of 5-70 mass% based on the total castable refractory. <P>COPYRIGHT: (C)2004,JPO

Description

【００１１】
また、本発明のキャスタブル耐火物の混練方法は、吸水処理済みの再利用材料以外の耐火材料と水分とを１５秒以上混練した後に、吸水処理済み再利用材料を投入して混練することを特徴とする。
【００１２】
【発明の実施の形態】
本発明者らは、再利用材料を用いたキャスタブル耐火物における上述の脱水層の形成を抑制する方法について種々検討を進めた結果、以下の知見を得た：
▲１▼吸水処理済み再利用材料を用いると、脱水層がほとんど形成されなくなる；▲２▼脱水層の形成を抑制するには、ある一定範囲の吸水状態にある吸水処理済み再利用材料を使用しなければならない；
▲３▼脱水層の形成を抑制するには、吸水処理済み再利用材料と再利用材料以外の耐火材料を同時に混練するか、あるいは再利用材料以外の耐火材料を予め混練して配合物を得た後に吸水処理済み再利用材料を投入する必要がある；
▲４▼吸水処理済み再利用材料以外の耐火材料と水を混練する前に吸水処理済み再利用材料を投入すると、水分が周囲に吸収されて再利用材料自体の水分量が不足し、結果として脱水層の形成が抑制できなくなる。
【００１３】
ここで、従来の再利用材料の粗大粒を水で濡らし吸水させたものを使用するキャスタブル耐火物において、施工体の含水率が不均一であるなどの問題点は、再利用材料の粗大粒の吸水状態やあるいは再利用材料の粗大粒の投入時期が適切に管理されていなかったことによる。従って、本発明の再利用材料を用いたキャスタブル耐火物の混練方法においては、吸水処理済みの再利用材料を使用する他、その吸水状態及び投入時期を適切に管理することを特徴とするものである。
【００１４】
以下、本発明の再利用材料を用いたキャスタブル耐火物の混練方法について、更に詳細に説明する。
本発明の再利用材料を用いたキャスタブル耐火物の混練方法に使用される再利用材料は、煉瓦や不定形耐火物の使用後品や未使用の下品などであり、用途に応じて種々の組成のものから適宜選択することができる。例えば、高炉樋用キャスタブル耐火物であれば、再利用材料としては、アルミナや炭化珪素、カーボン等を主な構成成分とするものが好適に使用できる。なお、使用後品を利用する場合には、スラグやメタルの付着やそれらの浸潤部を取り除くなどの処理を必要に応じて施したものを使用することが好ましい。また、必要に応じて粉砕、粒調等を行なったものを使用することができる。
【００１５】
次に、本発明方法に使用可能な再利用材料は、ＪＩＳ　Ｒ２２０５によって測定された吸水率が２％以上であるものが好ましい。再利用材料の吸水率が２％未満の場合は、吸水状態でなくとも脱水層の形成は、極く僅かであり、吸水処理済みの再利用材料を用いることによる効果は小さい。即ち、本発明の効果が明確に発揮されるのは、再利用材料の吸水率が２％以上の場合である。なお、再利用材料の吸水率が４％以上の場合、特に本発明の効果が大きい。
【００１６】
更に、本発明方法の効果を明確に発揮させるためには、吸水処理済みの再利用材料の吸水状態として下記の式（１）で求められる吸水指数が１０〜１００、好ましくは２５〜９５の範囲内のものでなければならない：
【数３】

ここで、吸水指数が大きい方が脱水層の形成が少なく好ましいが、それ以下の吸水指数においても、再利用材料周囲の脱水層の形成を低減することによって、効果を得ることができる。なお、前記吸水指数が１０未満では、吸水処理済みの再利用材料周囲の脱水層の形成を抑制する効果が不十分であり好ましくない。また、前記吸水指数が１００を超えると、余剰な水分によって流動性が過大となり、不良な施工体となることがあるため好ましくない。なお、前記吸水指数が９５以下であると、再利用材料中に吸水性がわずかに残存することにより、再利用材料と再利用材料以外の耐火材料粉末とがより密に接着されるため、より強固な組織を得ることができるためより好ましい。なお、再利用材料の吸水指数を適宜サンプリングして求める場合には、それらの平均値が上記範囲内に入っていることが好ましい。
【００１７】
本発明方法において、吸水処理済みの再利用材料の使用量は、キャスタブル耐火物全体に占める割合で５〜７０質量％の範囲で用いるのが好ましく、より好ましくは１０〜５５％の範囲内である。吸水処理済みの再利用材料の使用量が５質量％未満では、吸水処理済みの再利用材料を用いることの効果が明確に現れにくく、また、該使用量が７０％を超えると、再利用材料以外の耐火材料が少なすぎる状態となり、適切な施工性を確保できなくなるために好ましくない。
【００１８】
なお、吸水処理済みの再利用材料の粒度は、粒径１ｍｍ以上が７０質量％以上であることが好ましく、８０質量％以上がより好ましい。これより少ないと、微粉が多いため、吸水した状態にすることによって凝固したり、スラリー状になったりしてハンドリングが困難となるため、また、過剰の水分を含有し易くなり、施工時の水分管理が困難になるために好ましくない。なお、上述した脱水層の形成は、再利用材料の粒径が小さい場合にはほとんど起こらないため、微粉状態の再利用材料は、吸水状態である必要性がない。
【００１９】
なお、吸水処理済みの再利用材料は、再利用材料に吸収される水分以上の過剰な水分が付着していないことが好ましい。過剰な水分の付着は、施工水分の過剰添加につながり易く、混練時の水分調整を困難にするために好ましくない。
【００２０】
再利用材料への吸水処理は、再利用材料を一旦水没させて引き上げる方法、上から散水する方法などが考えられるが、上記吸水状態にすることが可能な方法であれば、特に手段は限定されない。ただし、吸水させてから使用するまでの期間が長い場合には、乾燥しないような対策を施すなどして、実際に混練する時点での吸水指数が、上記範囲に収まるようにしなければならない。なお、再利用材料に吸収させるものとしては、水の他、各種水溶液が使用可能である。水溶液としては、例えばアルギン酸ソーダ、グルコース、ブドウ糖、プロピレングリコールなどの保湿性を付与する水溶液を使用可能である。
【００２１】
吸水処理済み再利用材料は、混練時に他の耐火材料と混合することによって、本発明の効果を得ることができる。即ち、混練前に、吸水済みの再利用材料とそれ以外の耐火材料とを混合してはならない。また、吸水処理済みの再利用材料以外の耐火材料と水分とを１５秒以上、好ましくは２０秒以上混練した後に、吸水処理済みの再利用材料を投入して混合する方法がより効果的である。吸水処理済みの再利用材料以外の耐火材料と水分とを混練する前に他の乾燥状態の粉末と混合すると、周囲の乾燥状態の粉末に水分が吸収されることによって、吸水処理済み再利用材料中の水分が不足してしまい、結果として脱水層の形成が抑制できなくなり、また、施工可能な流動性を得るのに必要な水分量が極端に増加し、施工水分量の管理が困難となるために好ましくない。吸水処理済み再利用材料の混合時期は、本発明の効果を得るのに非常に重要な要件である。
【００２２】
本発明において、吸水処理済みの再利用材料以外の耐火材料及び添加剤としては、本発明の特徴を阻害しない範囲で、その用途に応じて任意に使用できる。また、吸水処理を行なっていない再利用材料を使用することも可能である。更に、添加剤としては、例えばアルミニウム、シリコンのような金属添加物、炭化ホウ素のような酸化防止剤、アルカリ金属リン酸塩、アルカリ金属カルボン酸塩、アルカリ金属フミン酸塩、ポリカルボン酸ナトリウムのような分散剤を挙げることができる。
【００２３】
本発明方法において、吸水処理済み耐火材料と水分とを混練する場合、水分としては水またはそれに準ずるもの例えばシリカゾルなどが使用できる。
【００２４】
本発明方法により得られたキャスタブル耐火物の施工形態は、特に限定されるものではなく、キャスタブル耐火物における一般的な施工方法が適用可能である。また、圧送や吹付け施工なども可能である。
【００２５】
【実施例】
以下に実施例を挙げて本発明のキャスタブル耐火物の混練方法を更に説明するが、本発明は以下の実施例に限定されるものではないことを理解されたい。
実施例
以下の表１に再利用材料の組成及び吸水率を、表２に再利用材料以外の耐火材料の配合物の配合割合をそれぞれ記載する。
上記再利用材料及び耐火材料の配合物を使用し、以下の表３に記載する配合割合及び混練条件にて、キャスタブル耐火物を調製した。得られたキャスタブル耐火物のタップフロー値（ＪＩＳ　Ｒ　２５２１）並びに施工体の諸特性を表３に併記する。
【００２６】
【表１】

【００２７】
【表２】

【００２８】
【表３】

【００２９】
表３において、「再利用材料以外の部分」及び「再利用材料の比率」とは、キャスタブル耐火物全体に占める各々の内掛け比率である。
また、「施工水分量」とは、再利用材料と再利用材料以外の配合物を合わせたキャスタブル耐火物全体の量１００％に対する混練時に加えた水分の外掛け比率である。
また、「総水分量」とは、キャスタブル耐火物全体の量１００％に対する再利用材料に含まれる水分と施工水分量とを併せた水分量の外掛け比率である。総水分量が少ない程、施工に必要な水分量は少ないと言える。
また、施工水分量は、タップフロー値が１８０程度になるように調整したものであるが、比較例８、９については、水分増によるタップフロー値の上昇が殆ど認められないことから、１０％で打ち切りとした。
また、「再利用材料投入時期」において、「混練時」とは、再利用材料以外の耐火材料の配合物に対して水を添加するのと同時に吸水処理済みの再利用材料を投入して混練したものであり、「２０秒後」とは、吸水処理済みの再利用材料以外の耐火材料の配合物に所定量の水を添加して混練を開始してから２０秒後に吸水処理済みの再利用材料を投入したものであり、「混練前」とは、再利用材料以外の耐火材料に水を添加する前に、吸水処理済みの再利用材料を投入したものである。
また、気孔率及び曲げ強さの測定に供した試験片は、流し込みによって得られた成形体を、実施例１と比較例５は酸化雰囲気、それ以外は還元雰囲気にて、１０００℃で３時間加熱処理を行なうことによって得たものである。なお、気孔率は、ＪＩＳ　Ｒ２２０５により測定した。また、曲げ強さは、ＪＩＳ　Ｒ　２５５３により測定した。
【００３０】
表３から明らかなように、本発明例１と比較例６、本発明例２、３と比較例７、本発明例４、５と比較例８、９のそれぞれの比較において、明確な差異が認められる。即ち、比較例６〜９においては、施工可能なタップフロー値を得るのにより多くの水分添加を必要とするばかりか、吸水処理済みの再利用材料が多くなり過ぎると、水分増により施工が困難となるのに対し、本発明例では、いずれも低水分量での施工が可能である。更に、注目すべきは、再利用材料に含まれる水分量を併せた総水分量においても、同じ配合の比較例と比べて少なくなっていることである。このような低水分量化、及び脱水層とその周囲との組織ギャップが解消されることにより、本発明例は比較例に比べて、低気孔率、高強度を達成しているものと考えられる。
【００３１】
【発明の効果】
本発明のキャスタブル耐火物の混練方法を用いることにより、再利用材料を用いた場合でも、従来よりも少ない水分添加量での施工が可能となるほか、従来では施工が困難であった再利用材料が多い配合においても、低水分量で施工性を確保することが可能となる。また、従来の吸水した再利用材料を用いたキャスタブル耐火物における問題点であった低水分量化及び脱水層と周囲との組織ギャップの解消により、従来と比べて低気孔率化及び高強度化を図ることができ、実炉使用時においては耐用性の向上を達成することができる。また、本発明例により、従来よりも多くの再利用材料を安定して使用することが可能になるため、再利用材料の有効活用によって、廃棄物を削減する効果も大きい。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for kneading castable refractories, and more particularly, to castable refractories obtained by recycling bricks and irregular-shaped refractories after use and unused products (hereinafter referred to as “reusable materials”). For the kneading method.
[0002]
[Prior art]
In recent years, from the viewpoint of effective utilization of resources or from the viewpoint of the global environment, recycling of waste materials has been studied in the field of refractories. Various methods have already been proposed for using recycled materials for amorphous refractories. For example, Japanese Unexamined Patent Publication No. Hei 11-12049 discloses a method in which an amorphous refractory material preliminarily kneaded with water is pumped through a transport pipe by a pump, and after the pumping, compressed air and a coagulant are added from the same path or another path. Amorphous refractories for wet spraying, which are sprayed from a spray nozzle onto an object to be machined, are made of irregularly shaped refractory materials, electrofused or sintered coarse refractory materials with a particle size of 10 to 40 mm, crushed bricks, bricks or irregular shaped One or two or more coarse particles consisting of crushed particles, which are waste materials of refractories, are added in an amount of 10 to 50% by weight (mass%) in an external manner, and the initial setting time after addition of the coagulant is within 1 minute. An amorphous refractory for wet spraying containing coarse particles is disclosed.
[0003]
JP-A-6-219853 discloses that a waste material of mag-carbon brick is sized to 5 to 60 mm and then immersed in a solution of amorphous silica suspended in water under vacuum for at least several tens of minutes. A method for treating mag-carbon brick debris, which is characterized by drying afterwards, is disclosed, and further, it is exemplified that the treated mag-carbon brick debris is blended with magnesia castable refractories.
[0004]
Further, JP-A-2001-335377 discloses that 30 to 70% by mass of a carbon-containing waste raw material aggregate composed of coarse particles having a particle size of 5 to 10 mm and fine particles having a particle size of 0.25 to 2 mm. A castable refractory is disclosed.
[0005]
As described above, castable refractories containing conventional recycled materials are prepared as coarse particles by directly or after performing necessary pretreatment after the recycled material is appropriately grained, or into relatively large particles. It was common to use them. However, when trying to construct a castable refractory using the above-mentioned reusable material, fluidity is insufficient, so it is necessary to increase the amount of water added, and it is difficult to obtain a dense construction body. . In particular, in the case of castable refractories to which a large amount of recycled materials are added, even if the amount of added water is increased, the fluidity is still insufficient, and it is difficult to secure workability. Further, even if the construction could be performed, a dense construction was not obtained due to the large amount of added water, and the corrosion resistance and strength were not satisfactory.
[0006]
On the other hand, Japanese Patent Application Laid-Open No. 61-215268 discloses a method in which a molten metal container is formed by pouring into a molten metal container having a steel shell provided outside and a refractory lining provided inside the steel shell. Amorphous refractories are mainly composed of a casting refractory material having a particle size of less than 10 mm, and a base material of 100 parts by weight (parts by mass) in dry weight, and a silica-based or alumina-based material which is uniformly mixed in the base material. An amorphous refractory for a molten metal container, comprising 5 to 60 parts by weight (parts by mass) of a coarse refractory having a particle diameter of 10 mm or more coated with a coating agent. That is, the publication discloses that the workability of the amorphous refractory is improved by using coarse particles coated with a silica-based or alumina-based coating agent for the amorphous refractory. However, coating with a silica-based or alumina-based coating agent is not realistic because it requires a great deal of labor and cost. Further, the publication exemplifies using coarse particles wetted with water and absorbing water in order to improve workability, but in this method, the water content of the construction body is not uniform. It is described that a satisfactory construction body could not be obtained for reasons such as
[0007]
[Problems to be solved by the invention]
In the castable refractory using the conventional reusable material as described above, the present inventors conducted various studies in order to clarify the cause of the problem that the amount of construction moisture increases or the workability cannot be secured. As a result of the repetition, the following findings were obtained:
(1) In the process of adding water to the refractory material and the reusable material other than the reusable material and kneading, and during the period from the kneading until the construction, the reusable material gradually absorbs moisture from the surroundings;
{Circle around (2)} As the recycled material absorbs moisture from the surroundings, a material layer (hereinafter, referred to as a dewatering layer) having a significantly reduced moisture content is formed around the recycled material and adheres to the particles of the recycled material. (It becomes a state like a mud dumpling with particles of recycled material as the core);
{Circle around (3)} Since the dewatered layer has no fluidity, it has a significant adverse effect on the fluidity of the castable refractory itself;
{Circle around (4)} Once formed, the dewatered layer is quite firm, and the dewatered layer is not completely eliminated by techniques such as extending the kneading time;
(5) When the added amount of the recycled material is increased, the dehydrated layer is fixed and the enlarged particles of the recycled material interfere with each other. Difficult to obtain sex;
{Circle around (6)} Since the moisture content of the dehydrated layer and its surroundings is significantly different, a structural gap is formed in the castable refractory construction;
{Circle around (7)} It is considered that the above phenomenon is influenced by the fact that the water absorption of the recycled material is higher than that of ordinary refractory materials other than the recycled material;
{Circle around (8)} The above-mentioned phenomenon becomes more remarkable in a method in which the recyclable material is introduced after the refractory material other than the recyclable material and water are kneaded.
[0008]
Therefore, an object of the present invention is to solve the deterioration of the workability of castable refractories using recycled materials by simple means, and to obtain a castable body which is denser than before and has excellent corrosion resistance and strength. An object of the present invention is to provide a method for kneading refractories.
[0009]
[Means for Solving the Problems]
The main cause of the above-mentioned problems of the prior art is the formation of a dewatering layer due to the absorption of water by the recycled material, and found that by suppressing the formation of the dehydration layer, the problems of the prior art can be overcome. It was completed.
[0010]
That is, in the method for kneading castable refractories of the present invention, in the method for kneading castable refractories using recycled materials as at least a part of the refractory raw material, the water absorption of the recycled materials is 2% or more and the following formula ( A water-absorbed product having a water-absorption index of 1) in the range of 10 to 100, and wherein the water-absorbed recycled material is used in an amount of 5 to 70% by mass of the entire castable refractory. And:
(Equation 2)

[0011]
Further, the method for kneading castable refractories of the present invention is characterized in that, after kneading a refractory material other than the water-absorbed recycled material and water for 15 seconds or more, the water-absorbed recycled material is charged and kneaded. And
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The present inventors have conducted various studies on a method for suppressing the formation of the above-mentioned dewatered layer in castable refractories using recycled materials, and obtained the following findings:
(1) When a water-absorbed recycled material is used, a dehydrated layer is hardly formed; (2) To suppress the formation of a dehydrated layer, use a water-absorbed recycled material that has a certain range of water absorption. Must;
(3) In order to suppress the formation of a dewatering layer, the water-absorbed recycled material and a refractory material other than the recycled material are simultaneously kneaded, or a refractory material other than the recycled material is previously kneaded to obtain a compound. After use, it is necessary to input the water-absorbed recycled material;
(4) If the water-absorbed recycled material is put in before mixing the water with the refractory material other than the water-absorbed recycled material, the water is absorbed into the surroundings and the water content of the recycled material itself becomes insufficient. The formation of a dehydrated layer cannot be suppressed.
[0013]
Here, in the castable refractory using the conventional coarse particles of the reusable material wetted with water and absorbing water, the problem that the water content of the construction body is not uniform is a problem of the coarse particles of the reusable material. This is because the state of water absorption and the timing of feeding coarse particles of reusable material were not properly controlled. Therefore, in the method for kneading castable refractories using the reusable material of the present invention, in addition to using the reusable material that has been subjected to the water-absorbing treatment, the water-absorbing state and the charging time are appropriately managed. is there.
[0014]
Hereinafter, the method for kneading the castable refractory using the recycled material of the present invention will be described in more detail.
The recycled materials used in the method for kneading castable refractories using the recycled materials of the present invention include bricks and used refractories of irregular-shaped refractories, and unused vulnerable articles. Can be selected as appropriate. For example, in the case of a castable refractory for a blast furnace gutter, a material containing alumina, silicon carbide, carbon, or the like as a main component can be suitably used as a reused material. When a post-use product is used, it is preferable to use a product which has been subjected to a treatment such as adhesion of slag or metal or removal of a permeated portion thereof as necessary. Further, if necessary, those which have been pulverized, adjusted in grain size and the like can be used.
[0015]
Next, the recycled material that can be used in the method of the present invention preferably has a water absorption of 2% or more as measured by JIS R2205. When the water absorption of the recycled material is less than 2%, the formation of the dewatered layer is extremely small even if the material is not in the water absorbing state, and the effect of using the recycled material after the water absorption treatment is small. That is, the effect of the present invention is clearly exhibited when the water absorption of the recycled material is 2% or more. When the water absorption of the recycled material is 4% or more, the effect of the present invention is particularly large.
[0016]
Further, in order to clearly show the effect of the method of the present invention, the water absorption index determined by the following formula (1) as a water absorption state of the water-absorbed recycled material is in the range of 10 to 100, preferably 25 to 95. Must be within:
[Equation 3]

Here, the larger the water absorption index is, the less the formation of the dewatering layer is preferable. However, even with the water absorption index lower than that, the effect can be obtained by reducing the formation of the dehydration layer around the reused material. If the water absorption index is less than 10, the effect of suppressing the formation of a dehydrated layer around the reused material after the water absorption treatment is insufficient, which is not preferable. On the other hand, if the water absorption index exceeds 100, the fluidity becomes excessive due to excess water, and a poor construction body may be formed, which is not preferable. When the water absorption index is 95 or less, the water absorption slightly remains in the reusable material, so that the reusable material and the refractory material powder other than the reusable material are more tightly bonded to each other. It is more preferable because a strong tissue can be obtained. In the case where the water absorption index of the reusable material is determined by appropriately sampling, it is preferable that the average value thereof is within the above range.
[0017]
In the method of the present invention, the amount of the water-absorbed recycled material used is preferably in the range of 5 to 70% by mass, more preferably in the range of 10 to 55% by mass of the total castable refractory. . If the used amount of the water-absorbed recycled material is less than 5% by mass, the effect of using the water-absorbed recycled material is hardly apparent, and if the used amount exceeds 70%, the recycled material is not used. The amount of refractory materials other than the above is too small, and it is not preferable because appropriate workability cannot be secured.
[0018]
The particle size of the recycled material after the water absorption treatment is preferably 70% by mass or more, more preferably 80% by mass or more when the particle size is 1 mm or more. If the amount is less than this, the amount of fine powder is large, so that it becomes solidified or becomes a slurry by absorbing water, making it difficult to handle. It is not preferable because management becomes difficult. In addition, since the formation of the above-mentioned dewatering layer hardly occurs when the particle size of the recycled material is small, the recycled material in a fine powder state does not need to be in a water-absorbing state.
[0019]
In addition, it is preferable that the water-absorbed reusable material does not have excess moisture more than the moisture absorbed by the reusable material. Excessive attachment of moisture is not preferable because it tends to lead to excessive addition of construction moisture and makes it difficult to adjust moisture during kneading.
[0020]
The method of absorbing water to the reusable material may be a method of once immersing the reusable material in water and pulling it up, or a method of sprinkling water from above. . However, if the period from water absorption to use is long, it is necessary to take measures to prevent drying, such that the water absorption index at the time of actual kneading falls within the above range. As the material to be absorbed by the reusable material, various aqueous solutions can be used in addition to water. As the aqueous solution, for example, an aqueous solution that imparts moisturizing properties, such as sodium alginate, glucose, glucose, and propylene glycol, can be used.
[0021]
The effect of the present invention can be obtained by mixing the water-absorbed recycled material with another refractory material during kneading. That is, the water-absorbed recycled material and other refractory materials must not be mixed before kneading. A more effective method is to knead the refractory material other than the water-absorbed recycled material with water for 15 seconds or more, preferably 20 seconds or more, and then add and mix the water-absorbed recycled material. . If the refractory material other than the water-absorbed recycled material is mixed with other dry powders before kneading, moisture is absorbed by the surrounding dry powder, and the water-absorbed recycled material is absorbed. Insufficient moisture in the water prevents the formation of a dewatering layer as a result, and the amount of water required to obtain workable fluidity increases extremely, making it difficult to control the amount of water in the work. Not preferred. The mixing time of the water-absorbed recycled material is a very important requirement for obtaining the effects of the present invention.
[0022]
In the present invention, the refractory material and the additive other than the water-absorbed recycled material can be arbitrarily used according to the application within a range not to impair the features of the present invention. It is also possible to use a recycled material that has not been subjected to a water absorption treatment. Further, as additives, for example, aluminum, metal additives such as silicon, antioxidants such as boron carbide, alkali metal phosphate, alkali metal carboxylate, alkali metal humate, sodium polycarboxylate Such dispersants can be mentioned.
[0023]
In the method of the present invention, when the water-absorbed refractory material and water are kneaded, the water may be water or an equivalent thereof such as silica sol.
[0024]
The construction form of the castable refractory obtained by the method of the present invention is not particularly limited, and a general construction method for castable refractories can be applied. In addition, pressure feeding, spraying, and the like are also possible.
[0025]
【Example】
Hereinafter, the method of kneading the castable refractory of the present invention will be further described with reference to Examples, but it should be understood that the present invention is not limited to the following Examples.
Examples Table 1 below shows the composition and water absorption of the recycled material, and Table 2 shows the blending ratio of the blend of the refractory material other than the recycled material.
A castable refractory was prepared using the above-mentioned mixture of the reusable material and the refractory material, at the mixing ratio and kneading conditions shown in Table 3 below. Table 3 also shows the tap flow value (JIS R 2521) of the castable refractory obtained and various characteristics of the construction.
[0026]
[Table 1]

[0027]
[Table 2]

[0028]
[Table 3]

[0029]
In Table 3, “parts other than recycled materials” and “ratio of recycled materials” are the respective inner ratios of the entire castable refractory.
Further, the “moisture content for construction” is an external ratio of water added at the time of kneading to 100% of the entire castable refractory including the recycled material and the compound other than the recycled material.
Further, the “total moisture content” is an outer ratio of the moisture content of the reusable material and the construction moisture content to 100% of the entire castable refractory. It can be said that the smaller the total water content, the smaller the water content required for construction.
In addition, the construction water content was adjusted so that the tap flow value was about 180. However, in Comparative Examples 8 and 9, since the rise in the tap flow value due to the increase in water was hardly recognized, it was 10%. And censored.
In the "Recycled material input timing", the term "at the time of kneading" means that at the same time as adding water to the compound of the refractory material other than the recycled material, the water-absorbed recycled material is charged and kneaded. "After 20 seconds" means that a predetermined amount of water is added to the composition of the refractory material other than the water-absorbed recycled material and the kneading is started, and 20 seconds after the water-absorbed recycled material is added. The used material is charged, and “before kneading” means that the water-absorbed recycled material is charged before adding water to the refractory material other than the recycled material.
The test piece subjected to the measurement of the porosity and the bending strength was a molded article obtained by pouring, Example 1 and Comparative Example 5 were in an oxidizing atmosphere, and the rest were in a reducing atmosphere at 1000 ° C. for 3 hours. It was obtained by performing a heat treatment. The porosity was measured according to JIS R2205. The flexural strength was measured according to JIS R 2553.
[0030]
As is clear from Table 3, there is a clear difference in the comparison between the inventive example 1 and the comparative example 6, the inventive examples 2 and 3 and the comparative example 7, and the inventive examples 4 and 5 and the comparative examples 8 and 9. Is recognized. That is, in Comparative Examples 6 to 9, not only is it necessary to add more water to obtain a tap flow value that can be applied, but if too much water-absorbed reused material is used, it is difficult to apply due to increased water. On the other hand, in the examples of the present invention, construction can be performed with a low water content. Further, it should be noted that the total water content including the water content contained in the recycled material is smaller than that of the comparative example having the same composition. It is considered that the present invention example achieved lower porosity and higher strength than the comparative example by reducing the water content and eliminating the tissue gap between the dehydrated layer and its surroundings.
[0031]
【The invention's effect】
By using the method for kneading castable refractories of the present invention, even when a reusable material is used, it is possible to perform construction with a smaller amount of added water than before, and a reusable material that was conventionally difficult to construct. It is possible to secure workability with a low water content even in a composition containing a large amount of water. In addition, low porosity and high strength have been achieved compared to the past by lowering the water content and eliminating the tissue gap between the dewatered layer and the surroundings, which were problems with castable refractories using recycled materials that absorbed water. It is possible to improve the durability when using the actual furnace. Further, according to the example of the present invention, more reused materials can be used more stably than in the past, so that the effective use of recycled materials has a great effect of reducing waste.

Claims (2)

In a method of kneading castable refractories for recycling used and / or unused bricks and / or irregular refractories as at least a part of the refractory raw materials, there is provided a method for mixing bricks and / or irregular refractories after use. And / or an unused product having a water absorption of 2% or more and having a water absorption index represented by the following formula (1) within the range of 10 to 100, and A method for kneading castable refractories, characterized in that after-use and / or unused products of amorphous refractories are used in an amount of 5 to 70% by mass of the entire castable refractories:

(In the formula, the recycled material means a used product and / or an unused product of a brick and / or an amorphous refractory.) After kneading the refractory material other than the used and / or non-used refractory material and / or the non-used refractory brick and / or irregular refractory for at least 15 seconds, the water-absorbed brick and / or irregular refractory The method for kneading castable refractories according to claim 1, wherein the used and / or unused products are charged and kneaded.