JP2018052751A - Cement mortar of refractory brick for blast furnace tuyere and blast furnace tuyere structure - Google Patents

Cement mortar of refractory brick for blast furnace tuyere and blast furnace tuyere structure Download PDF

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JP2018052751A
JP2018052751A JP2016187277A JP2016187277A JP2018052751A JP 2018052751 A JP2018052751 A JP 2018052751A JP 2016187277 A JP2016187277 A JP 2016187277A JP 2016187277 A JP2016187277 A JP 2016187277A JP 2018052751 A JP2018052751 A JP 2018052751A
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blast furnace
raw material
mortar
furnace tuyere
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JP6744794B2 (en
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俊久 佐々木
Toshihisa Sasaki
俊久 佐々木
倫 中村
Hitoshi Nakamura
倫 中村
和也 丸山
Kazuya Maruyama
和也 丸山
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Nippon Steel Corp
Krosaki Harima Corp
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Nippon Steel and Sumitomo Metal Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a cement mortar of refractory brick for blast furnace tuyere and a blast furnace tuyere structure capable of achieving both improvement of alkali resistance and improvement of adhesive strength of the cement mortar.SOLUTION: There is provided a silicon carbide based cement mortar of refractory brick for blast furnace tuyere which comprises fire resistant material, antioxidizing agent, and sodium silicate as binding agent. The fire resistant material comprises from 87 to 97 mass% of alumina raw material, and from 0.5 to 5 mass% of carbon raw material and/or silicon carbide raw material. The antioxidizing agent is formulated from 0.3 to 3 mass% in outer percentage relative to 100 mass% of the fire resistant material. The sodium silicate is formulated from 30 to 60 mass% in outer percentage relative to the total amount of 100 mass% of the fire resistant material and the antioxidizing agent. The silicon carbide based cement mortar contains 70 mass% or more of SiC as chemical component.SELECTED DRAWING: None

Description

本発明は、高炉羽口用耐火物れんがのモルタル及び高炉の羽口を構成する高炉羽口構造体に関する。   The present invention relates to a refractory brick mortar for a blast furnace tuyere and a blast furnace tuyere structure constituting a tuyere of a blast furnace.

高炉羽口構造体は、高炉羽口用耐火れんがをモルタルで接合して構築されるところ、高炉羽口用耐火れんがとしては従来一般的に、粘土質れんが又は高アルミナ質れんがが採用されてきた。しかし、これらの材質は、高炉稼動時に炉内に発生するアルカリガスがれんがに侵入し、れんがに体積膨張が生じるという問題があった。れんがに体積膨張が生じると、高炉羽口構造体の周囲の内張りの構造的緩み、あるいは水冷ジャケットの変形・破損の原因となる。そこで、耐アルカリ性付与のために、高炉羽口用耐火れんがに炭化珪素を主骨材とした材質の適用も検討されている(例えば、特許文献1参照)。   The blast furnace tuyere structure is constructed by joining refractory bricks for blast furnace tuyers with mortar, and as a refractory brick for blast furnace tuyere, clay bricks or high alumina bricks have been generally used. . However, these materials have a problem that the alkaline gas generated in the furnace during operation of the blast furnace enters the brick and causes volume expansion of the brick. When volume expansion occurs in the brick, it causes structural loosening of the lining around the blast furnace tuyere structure or deformation / breakage of the water cooling jacket. Therefore, in order to impart alkali resistance, application of a material having silicon carbide as a main aggregate for refractory bricks for blast furnace tuyere has also been studied (for example, see Patent Document 1).

一方、高炉羽口用耐火れんがを接合するモルタルは、耐火材料と結合剤を主成分として構成されるところ、通常、耐火材料としては接合する高炉羽口用耐火れんがと同材質のものが使用される。したがって、炭化珪素質の高炉羽口用耐火れんがには、炭化珪素原料を耐火材料とするモルタルが使用されている。また、通常、モルタルは水を加えて混練したものを使用するが、モルタルが高炉稼動時に高温にさらされると、モルタル中の水が水蒸気となり、この水蒸気により高炉羽口用耐火れんがの炭化珪素が酸化して耐用が低下する懸念がある。このため、モルタルの結合剤としては、タール又はフェノールレジンなどの有機質のものが使用されている。   On the other hand, mortar for joining refractory bricks for blast furnace tuyere is composed mainly of refractory materials and binders. Usually, refractory materials of the same type as refractory bricks for blast furnace tuyeres are used. The Therefore, a mortar using a silicon carbide raw material as a refractory material is used for the refractory brick for blast furnace tuyeres made of silicon carbide. In addition, mortar is usually kneaded with water added. However, when the mortar is exposed to high temperature during blast furnace operation, the water in the mortar becomes water vapor, which causes the silicon carbide of the refractory brick for blast furnace tuyere to be formed. There is a concern that the service life may be reduced due to oxidation. For this reason, organic substances such as tar or phenol resin are used as mortar binders.

しかし、このような有機質の結合剤を使用した場合、稼動時における高炉羽口構造体周囲の内張りの熱膨張による上方への突き上げ現象により、モルタルからなる目地部に亀裂が入る目地切れ現象が生じ易い。更に、例えばフェノールレジンを結合剤として使用した場合、モルタル(目地部)近傍は酸化雰囲気であるので、フェノールレジンが酸化して、モルタルの強度が低下して目地切れ現象を助長する。   However, when such an organic binder is used, a joint breakage phenomenon occurs in which the joint portion made of mortar cracks due to the upward push-up phenomenon due to the thermal expansion of the lining around the blast furnace tuyere structure during operation. easy. Further, for example, when phenol resin is used as a binder, since the vicinity of the mortar (joint portion) is an oxidizing atmosphere, the phenol resin is oxidized, and the strength of the mortar is lowered to promote the joint break phenomenon.

この目地切れ現象は、高炉羽口用耐火れんがとモルタルとの接着強度(以下、単に「モルタルの接着強度」又は「接着強度」という。)が低いことに起因して生じる。このため、目地切れ現象を解消するには、モルタルの接着強度を向上させる必要がある。   This joint breakage phenomenon is caused by low adhesive strength between the refractory brick for blast furnace tuyere and mortar (hereinafter simply referred to as “adhesive strength of mortar” or “adhesive strength”). For this reason, in order to eliminate the joint break phenomenon, it is necessary to improve the adhesive strength of the mortar.

また、高炉羽口用耐火物れんが及びその目地部であるモルタルは、炉内側である稼動面では1000℃まで加熱されているものの、稼動背面は200℃程度までしか温度が上がらない。このため、常温から1000℃迄の温度範囲における接着強度が必要となる。さらに、稼動背面においては、十分なカーボンボンドを形成しにくいので十分な接着強度が得られにくい問題があった。   Moreover, although the refractory brick for blast furnace tuyere and the mortar which is the joint part are heated up to 1000 ° C. on the operation surface inside the furnace, the temperature of the operation back surface only rises to about 200 ° C. For this reason, the adhesive strength in the temperature range from normal temperature to 1000 degreeC is required. Furthermore, since it is difficult to form a sufficient carbon bond on the operation back surface, there is a problem that it is difficult to obtain a sufficient adhesive strength.

モルタルの接着強度を向上させる技術としては、特許文献2に、結合剤として珪酸ソーダを使用する技術が開示されている。珪酸ソーダは比較的低温から接着強度が発現しやすいので、フェノールレジンと比較して有利である。   As a technique for improving the adhesive strength of mortar, Patent Document 2 discloses a technique using sodium silicate as a binder. Sodium silicate is more advantageous than phenolic resin because it tends to exhibit adhesive strength at relatively low temperatures.

しかし、本発明者らが、炭化珪素質の高炉羽口用耐火れんがを接合するために、炭化珪素原料を耐火材料とするモルタルに結合剤として珪酸ソーダを適用して高炉羽口構造体を試作したところ、モルタルからなる目地部に膨れや亀裂が発生し、結果として、十分なモルタルの接着強度が得られないことがわかった。   However, in order to join silicon carbide-based refractory bricks for blast furnace tuyere, we prototyped a blast furnace tuyere structure by applying sodium silicate as a binder to a mortar that uses silicon carbide as a refractory material. As a result, it was found that swelling and cracks occurred in the joint portion made of mortar, and as a result, sufficient adhesive strength of mortar could not be obtained.

すなわち、耐アルカリ性向上を目的に炭化珪素質の高炉羽口用耐火れんがを使用し、また、従来の技術常識に倣ってモルタルの耐火材料として炭化珪素原料を使用し、更に、モルタルの接着強度向上を目的に結合剤として珪酸ソーダを使用したものの、目的とするモルタルの接着強度向上は達成できなかった。   In other words, silicon carbide refractory bricks for blast furnace tuyeres are used for the purpose of improving alkali resistance, and silicon carbide raw materials are used as refractory materials for mortar in accordance with conventional common knowledge, and further improvement in adhesive strength of mortar. Although sodium silicate was used as a binder for the purpose of the above, improvement in the adhesive strength of the target mortar could not be achieved.

特開2002−195761号公報Japanese Patent Laid-Open No. 2002-195761 特開2000−282121号公報JP 2000-282121 A

本発明が解決しようとする課題は、耐アルカリ性向上とモルタルの接着強度向上を両立させうる高炉羽口用耐火物れんがのモルタル及び高炉羽口構造体を提供することにある。   The problem to be solved by the present invention is to provide a mortar and blast furnace tuyere structure for refractory bricks for blast furnace tuyere that can achieve both improved alkali resistance and improved adhesive strength of mortar.

本願発明者らが、上述した炭化珪素原料及び珪酸ソーダを使用したモルタルからなる目地部に膨れや亀裂が発生する原因を検討したところ、以下のメカニズムの推論を得るに至った。   The inventors of the present application have examined the cause of swelling and cracks occurring in the joint portion composed of the mortar using the above-described silicon carbide raw material and sodium silicate, and have obtained the following mechanism inference.

通常、炭化珪素原料は、炭素原料(C)と珪素原料(Si)を混合したものを電気炉(アチソン炉)に詰め、直接通電して得られる。つまり、SiO+3C→SiC+2COの反応により炭化珪素原料(SiC)が得られる。ただし、この反応が進むと、SiCとCとが反応して、炭化珪素原料の表面に金属Siが析出する。金属Siは、酸及び塩基と反応する両性金属である。このため、モルタルが珪酸ソーダを含む場合、珪酸ソーダは塩基性であるので、金属Siと珪酸ソーダの塩基性成分OHとが反応(Si+2OH→SiO+H)して、Hガスが発生する。このHガスの発生により、目地部に膨れや亀裂が発生する。 Usually, the silicon carbide raw material is obtained by charging a mixture of a carbon raw material (C) and a silicon raw material (Si) in an electric furnace (Acheson furnace) and directly energizing it. That is, a silicon carbide raw material (SiC) is obtained by a reaction of SiO 2 + 3C → SiC + 2CO. However, when this reaction proceeds, SiC and C react to deposit metal Si on the surface of the silicon carbide raw material. Metal Si is an amphoteric metal that reacts with acids and bases. For this reason, when mortar contains sodium silicate, since sodium silicate is basic, metal Si and basic component OH of sodium silicate react (Si + 2OH → SiO 2 + H 2 ) to generate H 2 gas. . Due to the generation of the H 2 gas, swelling and cracks occur in the joint portion.

そこで本発明者らは上記課題を解決するにあたり、耐アルカリ性向上のために炭化珪素質の高炉羽口用耐火れんがを使用すること、及びモルタルの接着強度向上のためにモルタルの結合剤として珪酸ソーダを使用することを前提としたうえで、モルタル中の耐火材料と珪酸ソーダとの反応によるHガスの発生を抑えつつ、耐アルカリ性向上とモルタルの接着強度向上を両立させるために、モルタルの結合剤以外の構成(耐火材料等)の見直しを図った。 In order to solve the above problems, the present inventors use silicon carbide-based refractory bricks for blast furnace tuyeres to improve alkali resistance, and sodium silicate as a mortar binder for improving the adhesive strength of mortar. In order to achieve both improved alkali resistance and improved adhesive strength of the mortar while suppressing the generation of H 2 gas due to the reaction between the refractory material in the mortar and sodium silicate, The structure other than the agent (refractory materials, etc.) was reviewed.

すなわち本発明によれば、化学成分としてSiCを70質量%以上含む炭化珪素質の高炉羽口用耐火れんがのモルタル及び当該モルタルを介して接合してなる高炉羽口構造体であって、前記モルタルは、耐火材料、酸化防止剤、及び結合剤として珪酸ソーダを含み、前記耐火材料は、アルミナ原料を87質量%以上97質量%以下、炭化珪素原料及び/又はカーボン原料を0.5質量%以上5質量%以下含み、前記酸化防止剤は、前記耐火材料100質量%に対して外掛けで0.3質量%以上3質量%以下配合され、前記珪酸ソーダは、前記耐火材料及び前記酸化防止剤の合量100質量%に対して外掛けで30質量%以上60質量%以下配合されている、高炉羽口構造体が提供される。   That is, according to the present invention, a mortar of refractory brick for silicon blast furnace tuyere containing 70% by mass or more of SiC as a chemical component, and a blast furnace tuyere structure bonded through the mortar, the mortar Includes a refractory material, an antioxidant, and sodium silicate as a binder. The refractory material is 87 mass% to 97 mass% alumina raw material, and 0.5 mass% or more silicon carbide raw material and / or carbon raw material. 5% by mass or less, and the antioxidant is blended in an amount of 0.3% by mass to 3% by mass with respect to 100% by mass of the refractory material, and the sodium silicate includes the refractory material and the antioxidant. There is provided a blast furnace tuyere structure that is blended in an amount of 30% to 60% by mass with respect to a total amount of 100% by mass.

本発明の高炉羽口構造体において目地部となるモルタルは、炭化珪素原料の配合量を5質量%以下に抑えている。したがって、炭化珪素原料に付随する金属Siと珪酸ソーダとの反応によるHガスの発生が抑制される。 In the mortar serving as a joint in the blast furnace tuyere structure of the present invention, the compounding amount of the silicon carbide raw material is suppressed to 5% by mass or less. Therefore, generation of H 2 gas due to the reaction between metal Si and sodium silicate accompanying the silicon carbide raw material is suppressed.

また、本発明においてモルタルの耐火材料の主材として使用するアルミナ原料は、炭化珪素原料及びカーボン原料に次いで耐アルカリ性に優れた原料であり、更に、本発明ではHガスの発生による膨れや亀裂の問題が生じない範囲で、耐アルカリ性に最も優れる炭化珪素原料ないしカーボン原料も使用する。しかも、本発明では酸化防止剤を配合するので、炭化珪素原料及びカーボン原料の酸化による消失が抑制され、これらの配合量が少量であっても、耐アルカリ性向上効果が継続的に得られる。 The alumina raw material used as the main material of the mortar refractory material in the present invention is a raw material having excellent alkali resistance next to the silicon carbide raw material and the carbon raw material. Further, in the present invention, blisters and cracks due to the generation of H 2 gas are used. As long as this problem does not occur, a silicon carbide raw material or carbon raw material having the highest alkali resistance is also used. Moreover, since the antioxidant is blended in the present invention, disappearance due to oxidation of the silicon carbide raw material and the carbon raw material is suppressed, and even when the blending amount is small, the alkali resistance improving effect is continuously obtained.

以上より、本発明によれば、モルタルの結合剤として珪酸ソーダを使用したことによる接着強度向上効果がいかんなく発揮されるとともに、十分な耐アルカリ性も確保することができる。   As described above, according to the present invention, the effect of improving the adhesive strength due to the use of sodium silicate as a mortar binder can be exhibited and sufficient alkali resistance can be ensured.

モルタルの接着強度測定用の試験機を示す。1 shows a testing machine for measuring adhesive strength of mortar.

本発明の高炉羽口構造体は、高炉羽口用耐火れんがをモルタルで接合して構築される。なお、高炉羽口構造体の構造及びその構築方法自体は周知である。   The blast furnace tuyere structure of the present invention is constructed by joining refractory bricks for blast furnace tuyere with mortar. The structure of the blast furnace tuyere structure and the construction method itself are well known.

本発明において高炉羽口用耐火れんがには、耐アルカリ性向上の点から、化学成分としてSiCを70質量%以上含む炭化珪素質の高炉羽口用耐火れんがを使用する。   In the present invention, a refractory brick for silicon blast furnace tuyere containing 70% by mass or more of SiC as a chemical component is used as the refractory brick for blast furnace tuyeres from the viewpoint of improving alkali resistance.

また、本発明において使用するモルタルは、耐火材料、酸化防止剤、及び結合剤として珪酸ソーダを含む。   In addition, the mortar used in the present invention includes refractory material, antioxidant, and sodium silicate as a binder.

そして耐火材料は、当該耐火材料100質量%中に、アルミナ原料を87質量%以上97質量%以下、炭化珪素原料及び/又はカーボン原料を0.5質量%以上5質量%以下含む。アルミナ原料が87質量%未満では、十分な耐アルカリ性が得られない。アルミナ原料が97質量%を超えると、炭化珪素原料及び/又はカーボン原料の配合量が少なくなるので、十分な耐アルカリ性が得られない。なお、アルミナ原料の配合量は、90質量%以上95質量%以下が好ましい。   And a refractory material contains 87 mass% or more and 97 mass% or less of alumina raw materials, and 0.5 to 5 mass% of silicon carbide raw materials and / or carbon raw materials in the said refractory material 100 mass%. If the alumina raw material is less than 87% by mass, sufficient alkali resistance cannot be obtained. If the alumina raw material exceeds 97% by mass, the compounding amount of the silicon carbide raw material and / or the carbon raw material is reduced, so that sufficient alkali resistance cannot be obtained. In addition, 90 mass% or more and 95 mass% or less are preferable for the compounding quantity of an alumina raw material.

また、炭化珪素原料及び/又はカーボン原料の配合量が0.5質量%未満では、十分な耐アルカリ性が得られない。炭化珪素原料及び/又はカーボン原料の配合量が5質量%を超えると、炭化珪素原料に付随する金属Siと珪酸ソーダとの反応によるHガスの発生が顕著となり、目地部に膨れや亀裂が発生する。なお、炭化珪素原料及び/又はカーボン原料の配合量は、1質量%以上3質量%以下がより好ましい。 Moreover, if the compounding quantity of a silicon carbide raw material and / or a carbon raw material is less than 0.5 mass%, sufficient alkali resistance will not be obtained. When the compounding amount of the silicon carbide raw material and / or the carbon raw material exceeds 5% by mass, the generation of H 2 gas due to the reaction between the metal Si accompanying the silicon carbide raw material and sodium silicate becomes remarkable, and the joints are swollen and cracked. Occur. In addition, as for the compounding quantity of a silicon carbide raw material and / or a carbon raw material, 1 to 3 mass% is more preferable.

アルミナ原料としては、焼結アルミナ、電融アルミナ、仮焼アルミナ等を使用できる。炭化珪素原料としては炭化珪素粉末を使用できる。カーボン原料としてはピッチ、コークス、黒鉛、カーボンブラック、無煙炭等を使用できる。いずれの原料も純度90%以上の高純度品を使用することが好ましい。   As the alumina raw material, sintered alumina, electrofused alumina, calcined alumina, or the like can be used. Silicon carbide powder can be used as the silicon carbide raw material. As the carbon raw material, pitch, coke, graphite, carbon black, anthracite, or the like can be used. It is preferable to use a high purity product having a purity of 90% or more for any of the raw materials.

また、本発明のモルタルは、アルミナ原料、炭化珪素原料及びカーボン原料以外にも耐火材料として粘土を添加してもよい。粘土を添加することで、モルタルの可塑性(作業性)を確保することができる。粘土は耐火材料中10質量%以下添加することが好ましい。粘土の配合量が10質量%を超えると、耐アルカリ性の低下が顕著となるので好ましくない。   Moreover, the mortar of this invention may add clay as a refractory material besides an alumina raw material, a silicon carbide raw material, and a carbon raw material. By adding clay, the plasticity (workability) of the mortar can be ensured. Clay is preferably added in an amount of 10% by mass or less in the refractory material. If the blending amount of the clay exceeds 10% by mass, the alkali resistance is significantly lowered, which is not preferable.

また、本発明のモルタルは、耐火材料、酸化防止剤、結合剤のほかに、本発明の効果を損なわない範囲で他の材料を含みうる。例えば、分散材、有機繊維等が挙げられ、これらは、耐火原料100質量%に外掛けで、例えば0.1質量%以下の範囲で配合されうる。   Moreover, the mortar of this invention can contain another material in the range which does not impair the effect of this invention other than a refractory material, antioxidant, and a binder. For example, a dispersing material, an organic fiber, etc. are mentioned, and these can be mix | blended in the range of 0.1 mass% or less, for example, on the refractory raw material 100 mass%.

酸化防止剤は、主に耐火原料中の炭化珪素原料及びカーボン原料の酸化防止のために配合する。このような酸化防止機能を有する酸化防止剤としては、炭化硼素(BC)、金属粉等が挙げられ、これらの1種又は2種以上の組合せを使用できる。酸化防止剤の配合量は、耐火材料100質量%に対して外掛けで0.3質量%以上3質量%以下とする。酸化防止剤の配合量が0.3質量%未満では、十分な酸化防止機能が得られず、炭化珪素原料及びカーボン原料が早期に酸化して消失する結果、これらによる耐アルカリ性向上効果が早期に失われる。酸化防止剤の配合量が3質量%を超えると、酸化防止機能が飽和し、材料コストの増大を招く。酸化防止剤の配合量は、1質量%以上3質量%以下が好ましい。 The antioxidant is blended mainly for the purpose of preventing oxidation of the silicon carbide raw material and the carbon raw material in the refractory raw material. Examples of the antioxidant having such an antioxidant function include boron carbide (B 4 C), metal powder, and the like, and one or a combination of two or more thereof can be used. The blending amount of the antioxidant is 0.3% by mass or more and 3% by mass or less with respect to 100% by mass of the refractory material. When the blending amount of the antioxidant is less than 0.3% by mass, a sufficient antioxidant function cannot be obtained, and as a result, the silicon carbide raw material and the carbon raw material are oxidized and disappeared at an early stage. Lost. When the blending amount of the antioxidant exceeds 3% by mass, the antioxidant function is saturated and the material cost is increased. As for the compounding quantity of antioxidant, 1 to 3 mass% is preferable.

結合剤として使用する珪酸ソーダの配合量は、耐火材料及び酸化防止剤の合量100質量%に対して外掛けで30質量%以上60質量%以下とする。珪酸ソーダの配合量が30質量%未満では、十分な接着強度が得られない。珪酸ソーダの配合量が60質量%を超えると、モルタル施工時に垂れが生じて作業性が悪くなる。珪酸ソーダの配合量は、40質量%以上50質量%以下が好ましい。珪酸ソーダとしては、Si/Na比の異なるものが有るが市販のものであればいずれを使用しても大差ない。   The amount of sodium silicate used as the binder is 30% by mass or more and 60% by mass or less as an outer shell with respect to 100% by mass of the total amount of the refractory material and the antioxidant. When the amount of sodium silicate is less than 30% by mass, sufficient adhesive strength cannot be obtained. When the amount of sodium silicate exceeds 60% by mass, sagging occurs during mortar construction, resulting in poor workability. The blending amount of sodium silicate is preferably 40% by mass or more and 50% by mass or less. Some sodium silicates have different Si / Na ratios, but any commercially available one is not much different.

ここで、本発明において使用するモルタルは、アルミナ原料を主材としている。これは、アルミナ原料が炭化珪素原料に次いで耐アルカリ性が良好だからである。また、アルミナ原料はHガスの発生を抑制できる効果も有する。さらに、炭化珪素原料及び/又はカーボン原料と酸化防止剤を所定量含むため、所望の耐アルカリ性を確保できる。ただし、材料固有の耐アルカリ性の点では、炭化珪素原料を主材とするモルタルに比べると若干劣ることは否めない。そこで、本発明においてより高度な耐アルカリ性を達成するには、モルタル中にアルカリ蒸気が侵入するのを防ぐために、モルタルからなる目地部の厚さ(目地厚)を小さくすることが有効である。従来一般的な高炉羽口構造体の目地厚は約2mmであるが、本発明では1mm以下とすることが好ましい。 Here, the mortar used in the present invention is mainly made of an alumina raw material. This is because the alumina raw material has good alkali resistance next to the silicon carbide raw material. Further, the alumina raw material has an effect of suppressing generation of H 2 gas. Furthermore, since the silicon carbide raw material and / or the carbon raw material and the antioxidant are included in a predetermined amount, desired alkali resistance can be ensured. However, in terms of the alkali resistance inherent to the material, it cannot be denied that it is slightly inferior to mortar containing silicon carbide as a main material. Therefore, in order to achieve higher alkali resistance in the present invention, it is effective to reduce the thickness of the joint portion (joint thickness) made of mortar in order to prevent alkali vapor from entering the mortar. Conventionally, the joint thickness of a general blast furnace tuyere structure is about 2 mm, but in the present invention, it is preferably 1 mm or less.

表1に示す各配合のモルタルについて、接着強度を測定するとともに耐アルカリ性を評価した。併せて作業性を評価し、これらをもって総合評価を行った。   About the mortar of each mixing | blending shown in Table 1, while measuring adhesive strength, alkali resistance was evaluated. At the same time, workability was evaluated, and comprehensive evaluation was performed with these.

なお、表1においてアルミナ原料としては電融アルミナ、炭化珪素原料としては炭化珪素粉末、カーボン原料としてはピッチを使用した。その他、耐火材料として粘土を使用した。また、酸化防止剤としては炭化硼素(BC)粉末を使用し、結合剤(珪酸ソーダ)としては3号水ガラスを使用した。 In Table 1, electrofused alumina was used as the alumina raw material, silicon carbide powder was used as the silicon carbide raw material, and pitch was used as the carbon raw material. In addition, clay was used as a refractory material. Further, boron carbide (B 4 C) powder was used as the antioxidant, and No. 3 water glass was used as the binder (sodium silicate).

Figure 2018052751
Figure 2018052751

モルタルの接着強度の測定は以下の方法で行った。
1.試験機
(1)図1に示す試験機を使用する。
2.操作
(1)供試れんがの114mmを長さに1辺40mm角に切り出し、長さの中央を切断して3対製作する。
(2)混練したモルタルを長さ2等分した切断面に一旦、試験片作製用スプーンで、すり込むように塗布したのち、これをスプーンで取り除く。再び、別の混練したモルタルを同じ要領で切断面に素早く塗布して所定目地の成形用ドリル棒を接着れんがのコーナーにはさみ所定目地を作る。
(3)ドリルを回転しながら抜き取り、スプーンで過剰のモルタルを除き、目地面とれんが面を平行に接着して24時間乾燥する。
(4)自然乾燥試験片を温度110±5℃の乾燥装置で12時間以上乾燥する。
(5)試験片3の接着面の幅及び厚さを0.1mmまで測り平均値を求める。
(6)図1の試験機において、荷重用ロール2の中心が目地(モルタル)6の中心に合致するように試験片をセットする。加圧速度は、原則として毎秒5kgで均一に加圧して最大荷重を求めた。
(7)加熱は図1に示す試験機を加熱炉内で行った。加熱炉内の炉内雰囲気は、酸化雰囲気又はN2あるいはArガスを吹き込んで不活性雰囲気とした。なお、試験片の温度は、稼動背面のモルタルの温度(200℃)、高炉稼動時におけるモルタルの低温部の温度(500℃)と高温部の温度(1000℃)の3つの温度でそれぞれ行った。
3.計算
(1)各試験片の接着強度Ba(kg/cm)は、次の式によって算出する。
Ba=(3W・l)/(2b・d
ここで、W:試験片の最大荷重(kg)
l:支点間距離(cm)
b:試験片の目地部の幅(cm)
d:試験片の目地部の厚さ(cm)
The adhesion strength of the mortar was measured by the following method.
1. Test machine (1) The test machine shown in FIG. 1 is used.
2. Operation (1) 114 mm of the test brick is cut into a 40 mm square on each side, and three pairs are manufactured by cutting the center of the length.
(2) The kneaded mortar is once applied to a cut surface obtained by dividing the kneaded mortar into halves with a spoon for preparing a test piece, and then removed with a spoon. Again, another kneaded mortar is quickly applied to the cut surface in the same manner, and a predetermined drill joint is formed at the corner of the brick to form a predetermined joint.
(3) Pull out while rotating the drill, remove excess mortar with a spoon, adhere the joint surface and brick face in parallel and dry for 24 hours.
(4) The natural drying test piece is dried for 12 hours or more with a drying apparatus having a temperature of 110 ± 5 ° C.
(5) Measure the width and thickness of the bonding surface of the test piece 3 to 0.1 mm and determine the average value.
(6) In the testing machine of FIG. 1, the test piece is set so that the center of the load roll 2 matches the center of the joint (mortar) 6. In principle, the maximum load was determined by applying a uniform pressure at 5 kg / sec.
(7) Heating was performed in the heating furnace using the testing machine shown in FIG. The furnace atmosphere in the heating furnace was an inert atmosphere by blowing an oxidizing atmosphere or N 2 or Ar gas. In addition, the temperature of the test piece was measured at each of three temperatures: the temperature of the mortar on the back of the operation (200 ° C.), the temperature of the low temperature portion (500 ° C.) and the temperature of the high temperature portion (1000 ° C.) during blast furnace operation. .
3. Calculation (1) The adhesive strength Ba (kg / cm 2 ) of each test piece is calculated by the following equation.
Ba = (3W · l) / (2b · d 2 )
Where W: Maximum load of the test piece (kg)
l: Distance between fulcrums (cm)
b: Width of joint part of test piece (cm)
d: Joint joint thickness (cm)

表1では、以上のようにして測定した200℃、500℃及び1000℃の接着強度が、1kg/cm以上の場合を◎(優)、1kg/cm未満0.7kg/cm以上の場合を○(良)、0.7kg/cm未満の場合を×(不可)として示した。接着強度が0.7kg/cm以上を合格基準とした理由は、500℃及び1000℃の接着強度が0.7kg/cm未満となると、稼動時における内張り材の熱膨張による上方への突き上げ現象によって、接着強度が耐えることが出来なくなり、モルタルの目地切れ現象が生じてしまうためである。 In Table 1, when the adhesive strength at 200 ° C., 500 ° C., and 1000 ° C. measured as described above is 1 kg / cm 2 or more, ◎ (excellent), less than 1 kg / cm 2 and 0.7 kg / cm 2 or more. The case was shown as ○ (good) and the case of less than 0.7 kg / cm 2 was shown as x (impossible). The reason why the adhesive strength is 0.7 kg / cm 2 or more as the acceptance criterion is that when the adhesive strength at 500 ° C. and 1000 ° C. is less than 0.7 kg / cm 2 , it is pushed upward due to the thermal expansion of the lining material during operation. This is because the phenomenon makes it impossible to withstand the adhesive strength, and a mortar joint breakage phenomenon occurs.

耐アルカリ性の評価は、アルカリ反応膨張の測定で行った。すなわち、20mm×20mm×80mmに作製した試験片を、コ−クス粉と炭酸カリウム粉(アルカリ源)との混合粉に埋め込んだ状態での加熱処理(1300℃×5時間)を5回繰り返した後、アルカリ反応膨張による線変化率を求めた。この線変化率の数値が小さいほど耐アルカリ性に優れる。   Evaluation of alkali resistance was performed by measuring alkali reaction expansion. That is, the heat treatment (1300 ° C. × 5 hours) in a state where a test piece prepared in 20 mm × 20 mm × 80 mm was embedded in a mixed powder of coke powder and potassium carbonate powder (alkali source) was repeated five times. Then, the linear change rate by alkali reaction expansion was calculated | required. The smaller the value of the linear change rate, the better the alkali resistance.

表1では、以上のようにして測定した線変化率が、5%以下の場合を◎(優)、5%超10%以下の場合を○(良)、10%超の場合を×(不可)として示した。なお、線変化率が10%以下を合格基準とした理由は、線変化率が10%超となると、モルタルが膨れてしまい、接着強度が低下してしまうためである。   In Table 1, when the linear change rate measured as described above is 5% or less, ◎ (excellent), 5% to 10% or less ○ (good), 10% or more × (impossible) ). The reason why the linear change rate is 10% or less is that the mortar swells and the adhesive strength decreases when the linear change rate exceeds 10%.

また、作業性については、施工時にモルタルの垂れがなく施工できた場合を◎(優)、施工時にモルタルの垂れが少しあったが施工は問題なくできた場合を○(良)、施工時にモルタルの垂れが顕著であり施工できなかった場合を×(不可)として評価した。   As for workability, ◎ (excellent) when the mortar was able to be constructed without dripping at the time of construction, ○ (good) when the mortar was drooled at the time of construction but there was no problem, and the mortar at the time of construction. The case where the drooping was remarkable and construction was not possible was evaluated as x (impossible).

そして、総合評価は、全ての評価で◎(優)の場合を◎(優)、全ての評価で×(不可)はないがいずれかの評価で○(可)があった場合を○(可)、いずれかの評価で×(不可)があった場合を×(不可)として評価した。   And overall evaluation is ◎ (excellent) in the case of ◎ (excellent) in all evaluations, ◯ (excluded) in all evaluations, but ○ (possible) in the case of any evaluation is ○ (possible) ), The case where there was x (impossible) in any evaluation was evaluated as x (impossible).

表1中、実施例1〜14は本発明の範囲内にモルタルを使用した例で、総合評価は◎(優)又は○(可)で良好な結果が得られた。   In Table 1, Examples 1 to 14 are examples in which mortar was used within the scope of the present invention, and good results were obtained with a comprehensive evaluation of ◎ (excellent) or ◯ (possible).

比較例1は、アルミナ原料の配合量が多く、かつ炭化珪素原料の配合量が少ない例で、耐アルカリ性が合格基準を満たしていない。   Comparative Example 1 is an example in which the amount of alumina raw material is large and the amount of silicon carbide raw material is small, and the alkali resistance does not satisfy the acceptance criteria.

比較例2は、炭化珪素原料の配合量が多い例で、珪酸ソーダと混合したときにHガスの発生が顕著に見られ、試験片の作製ができず、接着強度及び耐アルカリ性の測定ができなかった。 Comparative Example 2 is an example in which the amount of silicon carbide raw material is large. When mixed with sodium silicate, the generation of H 2 gas is noticeable, test pieces cannot be produced, and adhesion strength and alkali resistance are measured. could not.

比較例3は、アルミナ原料の配合量が少ない例で、耐アルカリ性が合格基準を満たしていない。また、粘土の配合量が多い点も耐アルカリ性が合格基準を満たしていない要因となっている。   The comparative example 3 is an example with few compounding quantities of an alumina raw material, and alkali resistance does not satisfy the acceptance criteria. In addition, the large amount of clay is also a factor that the alkali resistance does not meet the acceptance criteria.

比較例4は、酸化防止剤の配合量が少ない例で、耐アルカリ性が合格基準を満たしていない。   The comparative example 4 is an example with few compounding quantities of antioxidant, and alkali resistance does not satisfy the acceptance criteria.

比較例5は、珪酸ソーダの配合量が少ない例で、接着強度が合格基準を満たしていない。また、珪酸ソーダの配合量が少ないためモルタルの粘性が足りず、モルタルの垂れが顕著となり、作業性も×となった。   The comparative example 5 is an example with few compounding quantities of sodium silicate, and adhesive strength does not satisfy the acceptance criteria. Further, since the amount of sodium silicate was small, the viscosity of the mortar was insufficient, dripping of the mortar became remarkable, and the workability was also x.

比較例6は、珪酸ソーダの配合量が多い例で、モルタルの垂れが顕著となり、作業性が×となった。   Comparative Example 6 was an example in which the amount of sodium silicate was large. The dripping of the mortar was remarkable and the workability was x.

比較例7は、結合剤としてフェノールレジンを用いた例で、接着強度が合格基準を満たしていない。   The comparative example 7 is an example using a phenol resin as a binder, and the adhesive strength does not satisfy the acceptance criteria.

比較例8は、耐火材料の主材として炭化珪素原料を用いた例で、接着強度及び耐アルカリ性が合格基準を満たしていない。   Comparative Example 8 is an example in which a silicon carbide raw material is used as the main material of the refractory material, and the adhesive strength and alkali resistance do not satisfy the acceptance criteria.

1 球座面
2 荷重用ロール
3 試験片
4、5 支持用ロール
6 目地(モルタル)
DESCRIPTION OF SYMBOLS 1 Ball seat surface 2 Roll for load 3 Test piece 4, 5 Roll for support 6 Joint (mortar)

Claims (2)

化学成分としてSiCを70質量%以上含む炭化珪素質の高炉羽口用耐火れんがのモルタルであって、
耐火材料、酸化防止剤、及び結合剤として珪酸ソーダを含み、
前記耐火材料は、アルミナ原料を87質量%以上97質量%以下、カーボン原料及び/又は炭化珪素原料を0.5質量%以上5質量%以下含み、
前記酸化防止剤は、前記耐火材料100質量%に対して外掛けで0.3質量%以上3質量%以下含まれ、
前記珪酸ソーダは、前記耐火材料及び前記酸化防止剤の合量100質量%に対して外掛けで30質量%以上60質量%以下含まれる、高炉羽口用耐火れんがのモルタル。
A mortar of a refractory brick for silicon blast furnace tuyere containing 70% by mass or more of SiC as a chemical component,
Including sodium silicate as a refractory material, antioxidant, and binder,
The refractory material contains alumina raw material 87 mass% or more and 97 mass% or less, carbon raw material and / or silicon carbide raw material 0.5 mass% or more and 5 mass% or less,
The antioxidant is included in an amount of not less than 0.3% by mass and not more than 3% by mass with respect to 100% by mass of the refractory material,
The sodium silicate is a mortar of refractory bricks for blast furnace tuyere, which is contained in an amount of 30% by mass or more and 60% by mass or less on the basis of the total amount of the refractory material and the antioxidant of 100% by mass.
化学成分としてSiCを70質量%以上含む炭化珪素質の高炉羽口用耐火れんがが、モルタルを介して接合されてなる高炉羽口構造体であって、
前記モルタルは、耐火材料、酸化防止剤、及び結合剤として珪酸ソーダを含み、
前記耐火材料は、アルミナ原料を87質量%以上97質量%以下、カーボン原料及び/又は炭化珪素原料を0.5質量%以上5質量%以下含み、
前記酸化防止剤は、前記耐火材料100質量%に対して外掛けで0.3質量%以上3質量%以下含まれ、
前記珪酸ソーダは、前記耐火材料及び前記酸化防止剤の合量100質量%に対して外掛けで30質量%以上60質量%以下含まれる、高炉羽口構造体。
A blast furnace tuyere structure made of silicon carbide-based blast furnace tuyere containing 70% by mass or more of SiC as a chemical component is joined through mortar,
The mortar includes a refractory material, an antioxidant, and sodium silicate as a binder,
The refractory material contains alumina raw material 87 mass% or more and 97 mass% or less, carbon raw material and / or silicon carbide raw material 0.5 mass% or more and 5 mass% or less,
The antioxidant is included in an amount of not less than 0.3% by mass and not more than 3% by mass with respect to 100% by mass of the refractory material,
The sodium silicate is a blast furnace tuyere structure that is contained in an amount of 30% by mass or more and 60% by mass or less based on the total amount of the refractory material and the antioxidant of 100% by mass.
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WO2022025652A1 (en) * 2020-07-30 2022-02-03 주식회사 엔티에스 Method for manufacturing heat dissipation sheet using waste graphite

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