JP2016150886A - Hot repairing material for dc electric furnace - Google Patents
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- JP2016150886A JP2016150886A JP2015030428A JP2015030428A JP2016150886A JP 2016150886 A JP2016150886 A JP 2016150886A JP 2015030428 A JP2015030428 A JP 2015030428A JP 2015030428 A JP2015030428 A JP 2015030428A JP 2016150886 A JP2016150886 A JP 2016150886A
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
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- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
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Landscapes
- Ceramic Products (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Abstract
Description
本発明は、直流電気炉電極部とその周辺部を補修するための直流電気炉用熱間補修材に関し、更に詳細には、電気伝導性を必要とされる部位である直流電気炉の炉底電極とその周辺部を補修するための直流電気炉用導電性熱間補修材に関するものである。 The present invention relates to a hot repair material for a DC electric furnace for repairing a DC electric furnace electrode part and its peripheral part, and more specifically, a furnace bottom of a DC electric furnace that is a part that requires electrical conductivity. The present invention relates to a conductive hot repair material for a DC electric furnace for repairing an electrode and its peripheral portion.
直流電気炉は、炉底に設置された炉底電極と、炉蓋に設置された可動電極との間に直流電流を流し、ジュール熱を発生させ、そのジュール熱で鉄・スクラップを溶解して鋼を精練する炉である。炉底電極には３つのタイプがある。第１のタイプは、数本の径の大きい金属製の電極を設置し、その電極を通じて電流を流すと共に、電極の周囲を耐火物を施工するものである；第２のタイプは、カーボンを含有し、通電性を有する煉瓦を電極とするものである；第３のタイプは、多数の金属製のフィンあるいは丸棒を炉底煉瓦に埋め込む方法である。いずれの場合にも、炉底電極煉瓦は通電中に特に高温にさらされ、かつ溶融した鋼に接触する。また、その溶鋼を排出する際には、発生したスラグ成分とも接触して化学的反応が生じる。従って、炉底電極部付近の煉瓦は著しく損傷を受けることになる。 In a DC electric furnace, a DC current is passed between a furnace bottom electrode installed on the furnace bottom and a movable electrode installed on the furnace lid, generating Joule heat, and melting the iron and scrap with the Joule heat. It is a furnace for smelting steel. There are three types of furnace bottom electrodes. The first type installs several large-diameter metal electrodes, passes current through the electrodes, and constructs a refractory around the electrodes; the second type contains carbon The third type is a method in which a large number of metal fins or round bars are embedded in the furnace bottom brick. In either case, the bottom electrode brick is exposed to particularly high temperatures during energization and contacts molten steel. Further, when the molten steel is discharged, a chemical reaction occurs due to contact with the generated slag component. Therefore, the brick near the furnace bottom electrode part is significantly damaged.
直流電気炉の実炉の操業では、損傷した部位を吹付材や焼付材などの補修材により補修しながら操業が継続される。この際、第１のタイプの電気炉では、補修材に通電性が要求されないが、第２と第３のタイプの電気炉の場合には、補修材自体の電気伝導性が低いと炉底電極への通電が妨げられることになるため、このような電気炉を補修するための補修材は電気伝導性を有することが必須要件となる。 In the operation of a direct current electric furnace, the operation is continued while repairing the damaged part with a repair material such as spraying material or baking material. At this time, in the first type electric furnace, the repair material does not require electrical conductivity. However, in the case of the second and third types of electric furnaces, if the electric conductivity of the repair material itself is low, the bottom electrode Therefore, it is essential that the repair material for repairing such an electric furnace has electrical conductivity.
電気炉用補修材による補修は、通常以下のように行われる。すなわち、使用中に損傷が進行した部位を補修するに当たり、まず、溶鋼を排出して補修が必要な部位を露出させる。その露出部に常温の吹付材や焼付材を施工する。その後、炉熱で一定時間加熱したのち、通電によるスクラップ溶解作業を再開する。また、溶解熱を受けて、焼結が進む。このため、吹付材や焼付材の早急な強度発現が十分でない場合には、損傷が大きくなるため、早急な強度発現が求められる。 Repair with an electric furnace repair material is usually performed as follows. That is, in repairing a site where damage has progressed during use, first, the molten steel is discharged to expose the site requiring repair. A spraying material or baking material at room temperature is applied to the exposed portion. Then, after heating with furnace heat for a certain period of time, the scrap melting operation by energization is resumed. Also, sintering proceeds upon receiving heat of dissolution. For this reason, when the rapid strength expression of a spraying material or a baking material is not sufficient, since damage becomes large, rapid strength expression is required.
これまでの補修技術として、例えば、特許文献１には、上記第１のタイプの直流電気炉の補修方法として、炉体を例えばまず出鋼側に傾動して炉底電極のほぼ半数をホットヒールで覆い、残りの半数の電極を露出させた状態で不定形耐火物を吹付施工する方法が開示されており、特許文献１によれば、出鋼側の電極には不定形耐火物がコーティングされず、炉体を正立状態に戻した後にスクラップの装入を行って通電するとホットヒールによる通電が開始され、直立電気炉として直ちに機能し、また、非補修部の炉底耐火物は、次のチャージあるいは数チャージ後の非補修部耐火物に補修を要する段階で炉体を前回とは逆方向の排滓側に傾動して同様に補修を行った後、ホットヒールによる通電を再開することができるとしている。特許文献１に開示された直流電気炉の補修方法は、ドロマイト系吹付材のような電気伝導性を有しない不定形耐火物を使用することを前提としたものである。 As a conventional repair technique, for example, in Patent Document 1, as a repair method for the first type DC electric furnace, the furnace body is first tilted, for example, toward the steel output side, and almost half of the furnace bottom electrode is hot-heeled. And the other half of the electrode is exposed, and a method of spraying an amorphous refractory is disclosed. According to Patent Document 1, an electrode on the steel output side is coated with an amorphous refractory. First, when the furnace body is returned to the upright state and the scrap is charged and energized, energization by the hot heel starts and immediately functions as an upright electric furnace. After repairing the non-repaired part refractory after several charges or several charges, the furnace body is tilted in the direction opposite to the previous direction and repaired in the same way, and then energization with hot heels is resumed. I can do it. The repair method for a DC electric furnace disclosed in Patent Document 1 is based on the premise that an amorphous refractory having no electrical conductivity, such as a dolomite spray material, is used.
また、特許文献２には、直流電気炉電極部等の高温で且つ電気伝導性を必要とされる部位に用いられる、体積抵抗率が１．０×１０−２Ω・ｃｍ以下である導電性材料２０〜７０重量％と、耐火性材料８０〜３０重量％と、コールタールピッチ等の石炭系、石油系タール・ピッチやフェノール樹脂等の樹脂のような加熱により炭素結合を形成する結合材とからなる導電性不定形耐火物が開示されている。
Further, Patent Document 2 discloses a conductive material having a volume resistivity of 1.0 × 10 −2 Ω · cm or less, which is used in a portion requiring high electrical conductivity such as a DC electric furnace electrode part. 20 to 70% by weight of a material, 80 to 30% by weight of a refractory material, and a binder that forms a carbon bond by heating such as coal-based, coal-based tar pitch, resin such as petroleum-based tar pitch or phenol resin A conductive amorphous refractory comprising is disclosed.
更に、特許文献３には、耐火物原料１００重量％のうち、０．１２５ｍｍ以下の微粉部を３０〜５０重量％を含み、ノボラック型フェノール樹脂を有機溶剤に溶解してなるノボラック型フェノール樹脂溶液を外掛けでフェノール樹脂成分が１０〜２０重量％となる範囲で混練することを特徴とする、高温下における自己流動性をもつ不定形耐火物が開示されている。特許文献３に開示された不定形耐火物は、コールタール・ピッチを用いず、ノボラック型フェノール樹脂とテルペン類のような有機溶剤を併用することにより、発煙を抑制し、硬化時間を短縮することができるものである。特許文献３には、不定形耐火物が導電性を有するか、否かについての明確な記述はないが、ノボラック型フェノール樹脂とテルペン類のような有機溶剤の熱分解によってカーボンボンドが形成され、ある程度の導電性が確保できるものと推定される。特許文献３によれば、発煙を抑制することができ、かつ硬化時間は短縮可能であるとしている。 Furthermore, Patent Document 3 discloses a novolac type phenol resin solution obtained by dissolving 30 to 50% by weight of a fine powder portion of 0.125 mm or less out of 100% by weight of a refractory material and dissolving a novolac type phenol resin in an organic solvent. An amorphous refractory having self-fluidity at high temperatures is disclosed, characterized in that the phenol resin component is kneaded in an amount of 10 to 20% by weight. The amorphous refractory disclosed in Patent Document 3 suppresses fuming and shortens the curing time by using a novolak type phenolic resin and an organic solvent such as terpenes without using coal tar pitch. It is something that can be done. In Patent Document 3, there is no clear description as to whether or not the amorphous refractory has conductivity, but a carbon bond is formed by thermal decomposition of an organic solvent such as a novolak-type phenol resin and terpenes, It is estimated that a certain degree of conductivity can be secured. According to Patent Document 3, smoke generation can be suppressed and the curing time can be shortened.
また、特許文献４には、特許文献２、３と同様に熱間で炭化結合する有機結合剤を用いた焼付補修材として、耐火性粉体と、有機結合剤とを含み、熱焼失性バッグに収容されて補修対象炉に投入される焼付補修材であって、前記耐火性粉体１００質量％中に、粒径が１ｍｍ以上の耐火れんが破砕物を最大で５０質量％、前記耐火れんが破砕物との嵩比重差が０．５以下で粒径１ｍｍ以上の球状化処理された球状化粒子を９質量％以上、それぞれ含む焼付補修材が開示されている。特許文献４によれば、この焼付補修材は、良好な展開性及び焼結性を有するとしている。 Patent Document 4 includes a refractory powder and an organic binder as a baking repair material using an organic binder that is carbonized and bonded in the hot manner as in Patent Documents 2 and 3. A baked repair material that is housed in a furnace to be repaired and is put into a repair target furnace, and in 100% by mass of the refractory powder, a refractory brick having a particle size of 1 mm or more is crushed by up to 50% by mass and the refractory brick is crushed A baking repair material is disclosed that contains 9% by mass or more of spheroidized particles having a bulk specific gravity difference of 0.5 or less and a particle diameter of 1 mm or more. According to Patent Document 4, this baking repair material is said to have good expandability and sinterability.
しかしながら、特許文献１に開示されている補修方法は、上記第１のタイプの直流電気炉の補修方法であり、導電性を有しない不定形耐火物を用いて補修すると、補修部位以外の部分に電流が集中し、局部的な損傷が発生しやすいという問題点があった。
また、特許文献２に開示されている導電性不定形耐火物は、不定形耐火物自体が電気伝導性を有しており、耐食性・施工性共に良好であるが、施工時にタール・ピッチや樹脂の熱分解に伴い、有色で異臭の強い発煙が激しく生じるため使用現場の作業環境が著しく悪化するという問題点があった。また、タール・ピッチの発煙には、ＣＯ、ＮＯｘ、ＳＯｘ等の有害物質が含まれるため、近距離での作業は危険でもある。さらに、タール・ピッチ等を含む不定形耐火物は炭素結合を生成して硬化・接着するが、加熱による熱分解の時間が十分に取れない場合では接着強度は低くなり施工体が剥離するという問題点があった。
更に、しかしながら、特許文献３においても、コールタール・ピッチを使用した場合と比較して発煙は少なくなるものの、多少の有色の発煙が発生し、また、ノボラック型フェノール樹脂の熱分解に伴う耐え難い異臭が発生するため、作業環境悪化の問題点を解決するには至っていない。
また、特許文献４の焼付補修材では、耐火れんが破砕物の一例としてマグネシア−カーボン質れんが（以下、「マグ・カーボンれんが」）破砕物が挙げられており、炭素を含有する耐火れんがを破砕した破砕物を耐火材料として活用することで、耐火れんがが、未使用・使用後のどちらの状態であっても、耐火物の炭素含有量が増加して溶鋼やスラグに対して優れた耐食性を示すことが開示されているが、特許文献４の焼付補修材においても、ピッチ、タールなどの有機結合剤が用いられており、発煙により作業環境の悪化するという問題点が依然として残っている。
上述のように、従来の直流電気炉用補修技術では、コールタール・ピッチやフェノール樹脂のような導電性を有するカーボンボンドを形成する炭素含有材料を活用した補修材が使用されてきた。しかし、それらの炭素含有材料は、補修後の加熱による熱分解で有色の発煙があったり、耐え難い異臭が発生してしまうという問題点がある。しかし、それらを使用しない場合には、導電性が確保できず、また、施工体の焼結性が低くなり強度を発現できないという新たな問題点が発生する。
However, the repair method disclosed in Patent Document 1 is a repair method for the first type DC electric furnace described above. When repair is performed using an amorphous refractory having no electrical conductivity, it is applied to a portion other than the repair site. There was a problem that current was concentrated and local damage was likely to occur.
In addition, the conductive amorphous refractory disclosed in Patent Document 2 has an electrical conductivity, and the corrosion resistance and workability are good. In connection with the thermal decomposition, there is a problem that the working environment at the site of use is significantly deteriorated due to intense generation of colored smoke with a strong off-flavor. In addition, since tar and pitch fumes contain harmful substances such as CO, NO x , and SO x , work at a short distance is dangerous. In addition, amorphous refractories containing tar, pitch, etc. generate carbon bonds and cure / adhere, but if the time of thermal decomposition by heating is not sufficient, the adhesive strength becomes low and the construction body peels off There was a point.
Further, in Patent Document 3, however, although smoke generation is reduced as compared with the case where coal tar pitch is used, some colored smoke is generated, and unpleasant odor due to thermal decomposition of the novolac type phenol resin. Therefore, the problem of deterioration of the working environment has not been solved.
Moreover, in the baking repair material of patent document 4, the magnesia-carbon brick (henceforth "mag-carbon brick") crushed material is mentioned as an example of the refractory brick crushed material, and the refractory brick containing carbon was crushed. By utilizing the crushed material as a refractory material, the refractory bricks, regardless of whether they are unused or used, have an increased corrosion resistance against molten steel and slag due to an increase in the carbon content of the refractory. However, in the baking repair material of Patent Document 4, organic binders such as pitch and tar are used, and the problem that the working environment deteriorates due to smoke generation still remains.
As described above, in the conventional repair technique for a DC electric furnace, a repair material using a carbon-containing material forming a carbon bond having conductivity such as coal tar pitch or phenol resin has been used. However, these carbon-containing materials have a problem that colored smoke is generated due to thermal decomposition by heating after repair, and an unpleasant odor is generated. However, if they are not used, the conductivity cannot be ensured, and a new problem arises that the sinterability of the construction body becomes low and the strength cannot be expressed.
従って、本発明の目的は、使用時の発煙等による作業環境の悪化を防止し、かつ耐火物自体が導電性を有し、さらに耐用性の高い直流電気炉用導電性熱間補修材を得ることにある。 Accordingly, an object of the present invention is to obtain a conductive hot repair material for a DC electric furnace that prevents deterioration of the working environment due to smoke generation during use, and that the refractory itself has conductivity and has high durability. There is.
上記課題を解決するために、本発明者らは、発煙や悪臭の原因となる上記炭素含有材料を含まない直流電気炉用導電性熱間補修材について鋭意研究を行った結果、以下のような知見を得た。
すなわち、直流電気炉用熱間補修材の導電性については、適当な量の導電性材料を配合すれば十分に確保することができ、特許文献２〜４のようなカーボン結合を有する必要がないことが判明した。
また、直流電気炉用導電性熱間補修材の強度の発現について、様々な焼結助剤について検討した結果、ポルトランドセメントを添加することで施工体に高強度を付与できることが判明した。
本発明者らは、かかる知見を基に、本発明を完成するに至った。
In order to solve the above problems, the present inventors conducted intensive research on a conductive hot repair material for DC electric furnaces that does not contain the above-mentioned carbon-containing material that causes fuming and offensive odors. Obtained knowledge.
That is, the electrical conductivity of the hot repair material for a DC electric furnace can be sufficiently ensured by adding an appropriate amount of an electrically conductive material, and does not need to have a carbon bond as in Patent Documents 2 to 4. It has been found.
Moreover, as a result of examining various sintering aids regarding the development of the strength of the conductive hot repair material for DC electric furnaces, it was found that high strength can be imparted to the construction body by adding Portland cement.
Based on this knowledge, the present inventors have completed the present invention.
すなわち、本発明は、鉄粉あるいは鉄を主成分とする合金粉を５〜３０質量％、ポルトランドセメントを５〜２５質量％を含み、残部が塩基性耐火性骨材から構成されることを特徴とする直流電気炉用通電性補修材に係るものである。 That is, the present invention comprises 5-30% by mass of iron powder or an alloy powder containing iron as a main component, 5-25% by mass of Portland cement, and the balance is composed of a basic refractory aggregate. It relates to the conductive repair material for DC electric furnace.
また、本発明の直流電気炉用導電性熱間補修材は、更に、マグネシア・カーボンれんがの破砕物を含有することを特徴とする。 In addition, the conductive hot repair material for a DC electric furnace according to the present invention further includes a crushed material of magnesia / carbon brick.
本発明の直流電気炉用導電性熱間補修材によれば、補修材自体が電気伝導性を有し、かつポルトラントセメントを活用することで発煙による作業環境の悪化を抑え、さらに低融点である特徴から養生時間による耐用性の低下を改善することができるという効果を奏するものである。 According to the conductive hot repair material for DC electric furnaces of the present invention, the repair material itself has electrical conductivity, and by using portland cement, the deterioration of the working environment due to fuming is suppressed, and the melting point is low. From a certain feature, there is an effect that it is possible to improve a decrease in durability due to curing time.
本発明の直流電気炉用導電性熱間補修材は、鉄粉及び／または鉄（Ｆｅ）を主成分とする合金粉（以下、「鉄合金粉」と記載する）；ポルトランドセメント；及び塩基性耐火骨材から構成される。なお、本発明の直流電気炉用導電性熱間補修材では、ポルトランドセメントを使用しているにも拘わらず、水を一切使用せず、乾式の粉末状として使用することにも特徴がある。 The conductive hot repair material for a DC electric furnace of the present invention comprises iron powder and / or alloy powder mainly composed of iron (Fe) (hereinafter referred to as “iron alloy powder”); Portland cement; and basic Constructed from refractory aggregate. The conductive hot repair material for a DC electric furnace of the present invention is characterized in that it is used as a dry powder without using water at all, although Portland cement is used.
本発明の直流電気炉用導電性熱間補修材に使用される鉄粉または鉄合金粉は、熱間補修材に導電性を付与するための成分である。ここで、鉄粉、鉄合金粉は、安価であり、損耗により溶融して溶湯に混入しても不純成分とならない利点がある。更に、Ａｌ−Ｍｇ合金のように取扱い上で特別の注意を要するような危険性がない。なお、鉄粉、鉄合金粉は、それぞれを単独で使用しても、２種以上の混合物として用いても差し支えない。なお、鉄粉、鉄合金粉としては、例えば還元鉄粉、アトマイズ鉄粉、電解鉄粉等を挙げることができ、また、純鉄粉、快削鋼粉、低合金鋼粉、Ｃｒ系鉄合金粉、Ｎｉ系鉄合金粉、Ｃｒ−Ｍｏ系鉄合金粉、Ｃｏ系鉄合金粉等を挙げることができる。 The iron powder or iron alloy powder used for the conductive hot repair material for a DC electric furnace of the present invention is a component for imparting conductivity to the hot repair material. Here, iron powder and iron alloy powder are inexpensive and have the advantage that they do not become impure components even when melted due to wear and mixed into molten metal. Furthermore, there is no danger that requires special care in handling unlike Al-Mg alloys. The iron powder and iron alloy powder may be used alone or as a mixture of two or more. Examples of the iron powder and iron alloy powder include reduced iron powder, atomized iron powder, electrolytic iron powder, etc., and pure iron powder, free-cutting steel powder, low alloy steel powder, Cr-based iron alloy Examples thereof include powder, Ni-based iron alloy powder, Cr-Mo-based iron alloy powder, and Co-based iron alloy powder.
鉄粉あるいは鉄合金粉の配合量は、５〜３０質量％、好ましくは８〜２０質量％の範囲内である。これらの成分の配合量が５質量％未満であると、施工体に十分な電気伝導性を付与することができないために好ましくなく、また、３０質量％を超えると、鉄粉または鉄合金粉の酸化により施工体の組織が悪くなったり、稼働面付近で溶鉄が生成して直流電気炉用導電性熱間補修材の強度低下を引き起こし、耐用性が低下するので好ましくない。 The compounding quantity of iron powder or iron alloy powder is 5-30 mass%, Preferably it exists in the range of 8-20 mass%. When the blending amount of these components is less than 5% by mass, it is not preferable because sufficient electrical conductivity cannot be imparted to the construction body, and when it exceeds 30% by mass, iron powder or iron alloy powder is not preferable. It is not preferable because the structure of the construction body is deteriorated due to oxidation, or molten iron is generated in the vicinity of the operating surface, causing a decrease in strength of the conductive hot repair material for DC electric furnaces and reducing the durability.
なお、鉄粉、鉄合金粉の粒度は、特に限定されるものではないが、例えば０．０４５〜１．０ｍｍの範囲内に８５質量％以上含くまれることが好ましく、０．１５〜０．８ｍｍの範囲内に８５質量％以上含くまれることがより好ましい。ここで、０．０４５ｍｍ未満の粉末の割合が多くなると、後述する塩基性耐火骨材の粒度との差が大きくなって、分離しやすくなるため、導電性の不良や耐食性の悪化などが起こり易くなることがあるために好ましくない。また、１．０ｍｍより大きい粉末の割合が多くなると、施工体組織内に粉末が偏在してしまい、導電性が低下することがあるために好ましくない。 In addition, although the particle size of iron powder and iron alloy powder is not specifically limited, For example, it is preferable that 85 mass% or more is contained in the range of 0.045-1.0 mm, and 0.15-0. It is more preferable that 85% by mass or more is included in the range of 8 mm. Here, when the ratio of the powder of less than 0.045 mm increases, the difference from the particle size of the basic refractory aggregate described later increases, and it becomes easy to separate, so that poor conductivity and deterioration of corrosion resistance are likely to occur. This is not preferable. Moreover, when the ratio of the powder larger than 1.0 mm increases, since powder will be unevenly distributed in a construction body structure | tissue and electroconductivity may fall, it is unpreferable.
次に、本発明の直流電気炉用導電性熱間補修材は、ポルトランドセメントを含有する。ポルトランドセメントを添加することで、施工体を高強度化することができる。この理由は、以下のように考えられる。すなわち、ポルトランドセメントは、ＳｉＯ２、ＣａＯ、Ａｌ２Ｏ３、Ｆｅ２Ｏ３等から構成されるセメント化合物であり、セメントクリンカーの製造工程では、１５００℃程度の高温で焼成してセメント化合物を生成させると、１５〜２５質量％の液相もまた生成する。また、この液相を含む焼成物を急冷するため、ポルトランドセメント中には微細な結晶やガラス相が存在することとなる。これらの微細な結晶やガラス相は、加熱によって容易に再度液相となり、この液相が焼結助剤として働いて塩基性耐火骨材の焼結を促進して施工体の高強度化をもたらす。すなわち、ポルトランドセメントは、熱間で容易に溶融して塩基性耐火骨材の焼結を促進して施工体に強度を発現させることができる。 Next, the conductive hot repair material for a DC electric furnace of the present invention contains Portland cement. By adding Portland cement, the construction body can be strengthened. The reason is considered as follows. That is, Portland cement is a cement compound composed of SiO 2 , CaO, Al 2 O 3 , Fe 2 O 3 and the like. In the cement clinker manufacturing process, it is fired at a high temperature of about 1500 ° C. to produce a cement compound. When done, a liquid phase of 15-25% by weight is also produced. Further, since the fired product containing the liquid phase is rapidly cooled, a fine crystal or glass phase is present in the Portland cement. These fine crystals and glass phase easily become liquid phase again by heating, and this liquid phase works as a sintering aid to promote the sintering of the basic refractory aggregate, resulting in high strength of the construction body. . That is, Portland cement can be easily melted hot to promote the sintering of the basic refractory aggregate and to develop strength in the construction body.
本発明の直流電気炉用導電性熱間補修材に使用されるポルトランドセメントは、上述のようにＳｉＯ２、ＣａＯ、Ａｌ２Ｏ３、Ｆｅ２Ｏ３等から構成されるセメント化合物であり、建築用モルタルやコンクリートなどで使用される慣用のポルトランドセメントを使用することできる。ここで、ポルトランドセメントには様々なタイプのものがあり、普通ポルトランドセメントの他、早強タイプ、超早強タイプ、中庸熱タイプ、低熱タイプ、耐硫酸塩タイプなどのポルトランドセメントが知れられているが、そのいずれも使用できる。これらの中でも、特に市販の普通ポルトランドセメントは、最も安価で効果的、経済的であるため、普通ポルトランドセメントを使用することが好ましい。 The Portland cement used for the conductive hot repair material for DC electric furnaces of the present invention is a cement compound composed of SiO 2 , CaO, Al 2 O 3 , Fe 2 O 3, etc. Conventional Portland cement used in mortar and concrete can be used. Here, there are various types of Portland cement, and Portland cements such as early strength type, ultra-early strength type, medium heat type, low heat type, and sulfate resistant type are known in addition to ordinary Portland cement. However, any of them can be used. Of these, commercially available ordinary Portland cement is the most inexpensive, effective and economical, and it is preferable to use ordinary Portland cement.
本発明の直流電気炉用導電性熱間補修材において、ポルトランドセメントの含有量は５〜２５質量％の範囲内、好ましくは８〜２０質量％の範囲内である。ポルトラントセメントの含有量が５質量％未満の場合には、強度発現が十分でなく、耐用性が低下するために好ましくなく、また、２５質量％を超える場合には、施工体自体の焼結性は向上するものの、低融点物を多く生成するため耐食性が低下するため好ましくない。 In the conductive hot repair material for a DC electric furnace of the present invention, the content of Portland cement is in the range of 5 to 25% by mass, preferably in the range of 8 to 20% by mass. When the content of the portrant cement is less than 5% by mass, the strength development is not sufficient and the durability is lowered, which is not preferable. When the content exceeds 25% by mass, the construction body itself is sintered. However, since a lot of low melting point products are produced, the corrosion resistance is lowered, which is not preferable.
本発明の直流電気炉用導電性熱間補修材の残部は、塩基性耐火骨材から構成される。塩基性耐火骨材としては、ＭｇＯ及び／またはＣａＯを主成分とするもので、例えば、マグネシア、カルシア、ドロマイト等を挙げることができ、これらは、焼成クリンカー、電融クリンカー、天然及び合成の鉱物として主に用いることができるが、成形された耐火物の破砕物や使用後耐火物の破砕物も使用可能である。 The remainder of the conductive hot repair material for a DC electric furnace of the present invention is composed of a basic refractory aggregate. The basic refractory aggregate is mainly composed of MgO and / or CaO, and examples thereof include magnesia, calcia, dolomite and the like. These include calcined clinker, electrofused clinker, natural and synthetic minerals. However, a molded refractory crushed material and a refractory crushed material after use can also be used.
ここで、塩基性耐火骨材中のＭｇＯとＣａＯの合計含量は、８５質量％以上、好ましくは９０質量％以上である。ＭｇＯとＣａＯの合計含量が８５質量％未満では、不純物が多くなり耐食性が低下するために好ましくない。 Here, the total content of MgO and CaO in the basic refractory aggregate is 85% by mass or more, preferably 90% by mass or more. A total content of MgO and CaO of less than 85% by mass is not preferable because impurities increase and corrosion resistance decreases.
また、塩基性耐火骨材の最大粒径は、４〜１０ｍｍの範囲内であり、好ましくは４〜８ｍｍの範囲内である。塩基性耐火骨材の最大粒径が４ｍｍより小さい場合には、充填性が低下するために好ましくなく、また、１０ｍｍより大きいと、分散性が悪くなって遍在することがあるために好ましくない。 The maximum particle size of the basic refractory aggregate is in the range of 4 to 10 mm, preferably in the range of 4 to 8 mm. When the maximum particle size of the basic refractory aggregate is smaller than 4 mm, it is not preferable because the filling property is deteriorated, and when it is larger than 10 mm, it is not preferable because dispersibility may be deteriorated and ubiquitous. .
更に、塩基性耐火骨材の粒度は、１ｍｍ以上の大きい粒子（粗粒部）が６０〜９０質量％、好ましくは６５〜８５質量％、１ｍｍ未満の小さい粒子（微粉部）が１０〜４０質量％、好ましくは１５〜３５質量％の範囲内である。ここで、１ｍｍ以上の大きい粒子が６０質量％未満の場合には、微粉部が多くなり過ぎて施工体の展開性が低下するため好ましくない。また、１ｍｍ以上の大きい粒子が９０質量％を超えると、微粉部が少なく、施工体組織がボソついた状態になって耐食性が低下するため好ましくない。 Further, the particle size of the basic refractory aggregate is 60 to 90 mass%, preferably 65 to 85 mass%, and 10 to 40 mass% of small particles (fine powder portion) of less than 1 mm, with large particles (coarse portion) of 1 mm or more. %, Preferably in the range of 15 to 35% by weight. Here, when the size of large particles of 1 mm or more is less than 60% by mass, the fine powder portion is excessively increased, and the developability of the construction body is deteriorated. On the other hand, if the size of large particles of 1 mm or more exceeds 90% by mass, the fine powder portion is small and the construction structure becomes distorted and the corrosion resistance is lowered.
更に、本発明の直流電気炉用導電性熱間補修材には、マグネシア・カーボンれんがの破砕物を配合して耐食性を向上させることができる。マグネシア・カーボンれんがの破砕物を添加することで耐食性をより向上させることが可能となる。ここで、マグネシア・カーボンれんがには様々な種類のものがあるが、いずれも高耐食性、高耐熱スポーリング性が要求される部位で使用される緻密な組織を有しかつ高耐食性を有する材質として知られており、本発明の直流電気炉用導電性熱間補修材と比較して極めて高い耐食性を有することから、いずれの種類のマグネシア・カーボンれんがの破砕物でも使用できる。さらには、マグネシア・カーボンれんがは、カーボンを含有するため適度な電気伝導性を有するため、マグネシア・カーボンれんがの破砕物を添加しても、得られる施工体の導電性を阻害することがない。なお、マグネシア・カーボンれんがの破砕物としては、未使用品のれんがを粉砕した破砕物、使用後れんがを回収して粉砕した破砕物のどちらでも使用することができる。例えば、転炉用、溶鋼取鍋用などに製造したれんが、あるいは使用後のれんがを利用することができる。 Further, the conductive hot repair material for a DC electric furnace of the present invention can be mixed with a crushed material of magnesia / carbon brick to improve the corrosion resistance. Corrosion resistance can be further improved by adding crushed magnesia / carbon bricks. Here, there are various types of magnesia and carbon bricks, all of which have a dense structure and are used in parts that require high corrosion resistance and high heat spalling properties. Since it is known and has extremely high corrosion resistance as compared with the conductive hot repair material for DC electric furnaces of the present invention, any type of magnesia / carbon brick crushed material can be used. Furthermore, since magnesia / carbon brick contains carbon and has appropriate electrical conductivity, even if a crushed material of magnesia / carbon brick is added, the conductivity of the obtained construction body is not hindered. As the crushed material of magnesia / carbon brick, either a crushed material obtained by pulverizing unused bricks or a crushed material obtained by collecting and pulverizing bricks after use can be used. For example, a brick manufactured for a converter, a ladle for a molten steel, or a brick after use can be used.
本発明の直流電気炉用導電性熱間補修材におけるマグネシア・カーボンれんがの破砕物の含有量は、特に限定されるものではないが、好ましくは４０質量％以下、より好ましくは３〜４０質量％、更に好ましくは２０〜３５質量％の範囲内である。マグネシア・カーボンれんがの破砕物の含有量が３質量％未満の場合には、配合効果が発現し難く、また、４０質量％を超えると、高温下の酸化雰囲気でカーボンが脱炭してしまい、得られる施工体の気孔率が増加して耐食性が低下することがある。 The content of crushed magnesia / carbon bricks in the conductive hot repair material for DC electric furnaces of the present invention is not particularly limited, but is preferably 40% by mass or less, more preferably 3 to 40% by mass. More preferably, it is in the range of 20 to 35% by mass. When the content of crushed magnesia / carbon brick is less than 3% by mass, the compounding effect is difficult to develop, and when it exceeds 40% by mass, the carbon is decarburized in an oxidizing atmosphere under high temperature, The porosity of the resulting construction may increase and corrosion resistance may decrease.
なお、未使用のマグネシア・カーボンれんがの破砕物を使う場合には、フェノールレジンなどのバインダーの分解に伴う悪臭などが発生する可能性があるが、マグネシア・カーボンれんがの破砕品の添加量が上記範囲内であれば、バインダーなどの揮発分は、発煙、悪臭などの問題を発生し難い程度であり、たとえ発煙、悪臭などが発生したとしても問題とならない。しかしながら、マグネシア・カーボンれんがの破砕物としては、バインダーなどの揮発分の少ない使用後れんがの破砕物を使用することが好ましい。 If unused crushed magnesia / carbon brick is used, it may cause bad odor due to decomposition of binders such as phenol resin, but the added amount of crushed magnesia / carbon brick is above. If it is within the range, the volatile matter such as the binder is not likely to cause problems such as smoke and odor, and even if smoke or odor is generated, no problem occurs. However, as the crushed material of magnesia / carbon brick, it is preferable to use the crushed material of used brick with little volatile matter such as a binder.
マグネシア・カーボンれんがの粉砕物の粒度は、特に限定されるものではないが、好ましくは０．１〜１０ｍｍの範囲内、より好ましくは０．３〜５ｍｍの範囲内である。マグネシア・カーボンれんがの粉砕物の粒度が、０．１ｍｍより小さいと、焼結性を阻害することがあり、また、１０ｍｍより大きいと、破砕物が偏在して均一な組織にならないため強度や耐食性が局部的に弱い部分ができることがある。 The particle size of the pulverized magnesia / carbon brick is not particularly limited, but is preferably in the range of 0.1 to 10 mm, more preferably in the range of 0.3 to 5 mm. If the particle size of the magnesia / carbon brick pulverized product is smaller than 0.1 mm, the sinterability may be impaired. If the particle size is larger than 10 mm, the crushed material is unevenly distributed and does not form a uniform structure. There may be a locally weak part.
上述のように、本発明の直流電気炉用導電性熱間補修材は、ポルトランドセメントを含有するものであるが、通常のセメントモルタルのように水を添加することは好ましくない。この理由は、水の添加が補修部位を冷却して直流電気炉用導電性熱間補修材の焼結を阻害するのみならず、スクラップ溶解の際に水蒸気爆発の原因にもなり得るためである。 As described above, the conductive hot repair material for a DC electric furnace of the present invention contains Portland cement, but it is not preferable to add water as in ordinary cement mortar. The reason for this is that the addition of water not only inhibits the sintering of the conductive hot repair material for DC electric furnaces by cooling the repair site, but can also cause steam explosions during scrap melting. .
一方、発塵防止のために、本発明の直流電気炉用導電性熱間補修材に少量の油などの液体を加えることができる。この際、液体とポルトランドセメントが反応すると、粉状である本発明の直流電気炉用導電性熱間補修材が固化するため好ましくない。なお、油の添加量が多くなり過ぎると、発煙、悪臭などの問題が発生するとともに、本発明の直流電気炉用導電性熱間補修材を粉末状形態とすることが難しくなることがあるため、油を添加する場合でも、２質量％以下程度に抑えるべきである。なお、添加可能な油としては、例えば一号灯油、流動パラフィン、菜種油等を挙げることができる。 On the other hand, in order to prevent dust generation, a small amount of liquid such as oil can be added to the conductive hot repair material for DC electric furnace of the present invention. At this time, if the liquid and Portland cement react, the conductive hot repair material for a DC electric furnace according to the present invention which is powdery is solidified, which is not preferable. If the amount of oil added is too large, problems such as smoke and odors occur, and it may be difficult to make the conductive hot repair material for a DC electric furnace of the present invention into a powder form. Even when oil is added, it should be suppressed to about 2% by mass or less. Examples of oils that can be added include No. 1 kerosene, liquid paraffin, and rapeseed oil.
本発明の直流電気炉用導電性熱間補修材の製造方法は、特に限定されるものではなく、例えば、原料を秤量し、マラーミキサー、コナーミキサー、ナウターミキサー、オムニミキサーなどを用いて混合し、混合品をフレコンバッグ、プラスチック製の袋、紙袋などに入れて製品として出荷することができる。 The method for producing a conductive hot repair material for a DC electric furnace of the present invention is not particularly limited. For example, raw materials are weighed and mixed using a Muller mixer, a Conner mixer, a Nauter mixer, an omni mixer, etc. The mixed product can be shipped as a product in a flexible container bag, a plastic bag, a paper bag, or the like.
また、本発明の直流電気炉用導電性熱間補修材の施工方法もまた特に限定されるものではなく、例えば直流電気炉の使用中に損傷の進んだ部位を補修する当たり、まず、溶鋼を排出して補修が必要な部分を露出させ、その露出部に本発明の直流電気炉用導電性熱間補修材を投入する。投入方法が限定されないが、例えば、プラスチック製袋に入れて投入する、スコップを用いて投入する、フレコンバッグごと直流電気炉に投入するなどの方法が採用できる。本発明の直流電気炉用導電性熱間補修材は粉体であっても、適度な流動性を有するので補修が必要な部位に、直流電気炉用導電性熱間補修材を供給することができる。なお、必要に応じて、投げ込まれた直流電気炉用導電性熱間補修材の表面をレーキなどによって均すこともできる。ここで、投入された直流電気炉用導電性熱間補修材は常温であるが、炉熱で一定時間加熱されることによって、焼結して強度が発現する。その後、直流電気炉にスクラップを投入して通電により溶解作業を再開することができる。溶解作業による熱で更に焼結が進み、高耐用な施工体（補修材層）を得ることが可能となる。 In addition, the method of applying the conductive hot repair material for DC electric furnace of the present invention is not particularly limited. For example, when repairing a damaged part during use of the DC electric furnace, The portion that needs to be discharged and repaired is exposed, and the conductive hot repair material for DC electric furnace of the present invention is put into the exposed portion. The charging method is not limited, but for example, a method of charging in a plastic bag, charging using a scoop, or charging the flexible container bag together with a DC electric furnace can be employed. Even if the conductive hot repair material for a DC electric furnace of the present invention is a powder, the conductive hot repair material for a DC electric furnace can be supplied to a portion requiring repair because it has an appropriate fluidity. it can. In addition, the surface of the thrown-in electroconductive hot repair material for DC electric furnaces can also be leveled by rake etc. as needed. Here, although the charged hot repair material for DC electric furnace is at room temperature, it is sintered and develops strength by being heated with furnace heat for a certain period of time. Thereafter, the scraping operation can be resumed by energizing the DC electric furnace with scrap. Sintering further proceeds with heat from the melting operation, and a highly durable construction body (repair material layer) can be obtained.
以下、本発明の直流電気炉用導電性熱間補修材を更に具体的に説明する。
表１に、本発明品の配合例を示し、表２に、比較品の配合例を示す。
鉄粉１は、市販の鉄粉であり、粒度は１．０〜０.０７５ｍｍであり、０．５〜０．１５ｍｍ域に６０〜７０質量％が分布した。また，粒度の影響を見るために、篩い分けして粒度１ｍｍ超の鉄粉２と、粒度０．０４５ｍｍ未満の鉄粉３とした。
ポルトランドセメントは、市販のもので住友大阪セメント株式会社製の普通ポルトランドセメントと早強ポルトランドセメントを使用した。
塩基性骨材として、ドロマイトクリンカーを使用した。組成は、ＣａＯ＝６０質量％、ＭｇＯ＝３３質量％、Ｆｅ２Ｏ３＝６質量％であった。ドロマイトクリンカーは篩い分けして５〜１ｍｍのドロマイト１と、１ｍｍ未満のドロマイト２とした。
マグネシア・カーボンれんがの破砕物は、製鉄所で発生した使用後の取鍋用マグネシア・カーボンれんが（Ｃ＝１５質量％）と転炉用マグネシア・カーボンれんが（Ｃ＝２０質量％）であった：
ＭｇＯ−Ｃ破砕物１は、取鍋用マグネシア・カーボンれんがの破砕物であり、その粒度は５〜１ｍｍ＝６５質量％、１〜０．１ｍｍ＝３５質量％であった；
ＭｇＯ−Ｃ破砕物２は、転炉用マグネシア・カーボンれんがの破砕物であり、その粒度は５〜１ｍｍ＝６５質量％、１〜０．１ｍｍ＝３５質量％であった；
ＭｇＯ−Ｃ破砕物３は、取鍋用マグネシア・カーボンれんがの破砕物であり、その粒度は２５〜１０ｍｍであった；
ＭｇＯ−Ｃ破砕物４は、転炉用マグネシア・カーボンれんがの破砕物であり、その粒度は０．１ｍｍ未満であった。
Hereinafter, the conductive hot repair material for a DC electric furnace of the present invention will be described more specifically.
Table 1 shows a blending example of the product of the present invention, and Table 2 shows a blending example of the comparative product.
The iron powder 1 is a commercially available iron powder, the particle size is 1.0-0.075 mm, and 60-70 mass% was distributed in the 0.5-0.15 mm area. Moreover, in order to see the influence of a particle size, it sieved and it was set as the iron powder 2 with a particle size over 1 mm, and the iron powder 3 with a particle size of less than 0.045 mm.
Portland cement is commercially available, and ordinary Portland cement and early strength Portland cement manufactured by Sumitomo Osaka Cement Co., Ltd. were used.
Dolomite clinker was used as the basic aggregate. The composition was CaO = 60 mass%, MgO = 33 mass%, and Fe 2 O 3 = 6 mass%. The dolomite clinker was sieved to 5 to 1 mm dolomite 1 and less than 1 mm dolomite 2.
The crushed material of magnesia / carbon brick was magnesia / carbon brick for ladle after use (C = 15% by mass) and magnesia / carbon brick for converter (C = 20% by mass) generated in an ironworks:
MgO-C crushed material 1 is a crushed material of magnesia carbon brick for ladle, and its particle size was 5-1 mm = 65 mass%, 1-0.1 mm = 35 mass%;
MgO-C crushed material 2 is a crushed material of magnesia carbon brick for converters, and its particle size was 5-1 mm = 65 mass%, 1-0.1 mm = 35 mass%;
MgO-C crushed material 3 is a crushed material of magnesia carbon brick for ladle, and its particle size was 25 to 10 mm;
The MgO-C crushed material 4 was a crushed material of magnesia carbon brick for converters, and its particle size was less than 0.1 mm.
また、本発明品及び比較品の補修材の諸特性を表１及び２に併記する。なお、諸特性の評価方法は以下の通りである：
焼結性は、本発明品及び比較品の補修材をアルミナ質キャスタブル製の型枠に充填し、型枠ごと酸化雰囲気中、１３５０℃で３時間焼成して焼結体を得た。この際、型枠の内寸を幅３０ｍｍ、厚み３０ｍｍ、長さ１４０ｍｍとし、補修材の充填量を２５０ｇとした。冷却後、得られた焼結体を型枠から取り出して試験片し、外観を目視観察して焼結性の評価とした。しっかり形状を保っているものを◎、やや強く押すと角部が削れるものを○、形状が保たれず崩れてしまうものを×の３段階で評価した；
通電性は、上記試験片の１４０ｍｍ方向の電気抵抗値を絶縁抵抗計（三和電気計器製：ＤＭ−５２５７）で測定し、抵抗値が５０ＭΩ未満であれば◎、５０ＭΩ以上、１００ＭΩ未満であれば○として通電性ありと評価し、１００ＭΩより大きいものを×として通電性なしと評価した。なお、焼結性試験で形状が崩れたものについて、電気抵抗測定は行わなかった；
施工性は、本発明品及び比較品の補修材８００ｇをナイロン袋に詰め（四角いプラスチック製袋のコーナー部に詰めて）円錐状にしたものを、アルミナキャスタブル製の板（３００×３００×２０ｍｍ）の上に置き、１５００℃で３時間加熱した。加熱によりナイロン袋が破れ、補修材粉末が崩れ広がった形状の焼結体を得た。焼結体の広がり径により展開性を、また、骨材が偏りなく分散しているかどうかを目視により調べて、施工性の評価とした。施工性が極めて良好を◎、施工性が良好を○、施工性がやや劣るが許容範囲であるものを△、施工性が不十分なものを×とした（ただし、本発明品、比較品共×評価のものはなかった）；
圧縮強度は、焼結性を調査した試験片を用い、ＪＩＳ Ｒ ２５５３（キャスタブル耐火物の強さ試験方法）に準じて測定した；
耐食性の評価には、回転ルツボ法を用いた。試験条件は１６００℃（酸化雰囲気）で行い、スラグは一定時間経過する毎にルツボから排出し新鮮なスラグに交換した。スラグ交換の頻度は、６０分に１回の計４回行った。スラグはＣａＯ／ＳｉＯ２＝４．５の電気炉スラグを用いた。侵食量はポルトランドセメント無添加の侵食量を１００とした指数で示し、数値が多いほど耐食性に劣ることを示している。
Tables 1 and 2 also show the characteristics of the repair material of the present invention product and the comparative product. The evaluation methods for various properties are as follows:
Sinterability was obtained by filling the repair material of the product of the present invention and the comparative product into a mold made of alumina castable and firing the mold together in an oxidizing atmosphere at 1350 ° C. for 3 hours to obtain a sintered body. At this time, the inner dimensions of the mold were 30 mm wide, 30 mm thick and 140 mm long, and the filling amount of the repair material was 250 g. After cooling, the obtained sintered body was taken out of the mold and used as a test piece, and the appearance was visually observed to evaluate the sinterability. Evaluation was made in three stages: ◎ for those that maintained a firm shape, ◯ for those whose corners were shaved when pressed slightly, and × for those that did not retain their shape and collapsed;
For electrical conductivity, the electrical resistance value in the 140 mm direction of the test piece is measured with an insulation resistance meter (manufactured by Sanwa Denki Keiki Co., Ltd .: DM-5257). If it was evaluated as ○, it was evaluated as having electrical conductivity, and a value larger than 100 MΩ was evaluated as being × as having no electrical conductivity. In addition, the electrical resistance measurement was not performed for those whose shape collapsed in the sinterability test;
As for workability, 800 g of the repair material of the present invention and the comparative product are packed in a nylon bag (packed in the corner of a square plastic bag) into a conical shape, and an alumina castable plate (300 × 300 × 20 mm) And heated at 1500 ° C. for 3 hours. A sintered body having a shape in which the nylon bag was broken by heating and the repair material powder collapsed and spread was obtained. The expansibility of the sintered body was evaluated by visual inspection and whether or not the aggregate was evenly dispersed was determined as an evaluation of workability. The workability is very good, the workability is good, the workability is slightly inferior but acceptable, and the workability is inferior. × There was no evaluation);
The compressive strength was measured in accordance with JIS R 2553 (castable refractory strength test method) using a test piece investigated for sinterability;
A rotating crucible method was used for evaluation of corrosion resistance. The test conditions were 1600 ° C. (oxidizing atmosphere), and the slag was discharged from the crucible and replaced with fresh slag every time a fixed time passed. The frequency of slag exchange was 4 times, once every 60 minutes. As the slag, an electric furnace slag of CaO / SiO 2 = 4.5 was used. The amount of erosion is indicated by an index with the amount of erosion without addition of Portland cement taken as 100, and the greater the value, the lower the corrosion resistance.
上記表１において、本発明例１〜１０は、鉄粉量と粒度を変化させたものである。また、本発明品１１〜１４は普通ポルトランドセメントの量を変化させたものであり、本発明品１５は、早強ポルトランドセメント使用したものである。本発明品１６〜１８は、ドロマイトの粒度を変更したものである。本発明品１〜１８は、いずれも焼結性、通電性、施工性、圧縮強度、耐食性に優れ、導電性を必要とされる直流電気炉用導電性熱間補修材として優れた特性を有することが解る。
更に、本発明品１９〜２５は、ＭｇＯ−Ｃ破砕物１の配合量を変えた場合あり，本発明品２６〜２８は、マグネシア−カーボンれんがの破砕品のソースと粒度を変えた場合である。ドロマイトクリンカーとマグネシア−カーボンれんがの破砕品を併用することで、一層の耐食性の向上を図ることができることが解る。
In the said Table 1, this invention examples 1-10 change iron powder amount and a particle size. Moreover, this invention goods 11-14 change the quantity of normal Portland cement, and this invention goods 15 use the early strong Portland cement. Invention products 16 to 18 are obtained by changing the particle size of dolomite. The inventive products 1 to 18 are all excellent in sinterability, electrical conductivity, workability, compressive strength, corrosion resistance, and excellent properties as a conductive hot repair material for DC electric furnaces that require electrical conductivity. I understand that.
Furthermore, this invention goods 19-25 are the cases where the compounding quantity of MgO-C crushed material 1 is changed, and this invention goods 26-28 are the cases where the source and particle size of the crushed goods of magnesia-carbon brick are changed. . It can be seen that a further improvement in corrosion resistance can be achieved by using a crushed product of dolomite clinker and magnesia-carbon brick.
上記表２において、比較品１は、鉄粉を含まない場合であるが、通電性が悪いだけではなく、焼結性も劣るものであった。焼結性が劣る原因は、鉄が酸化して生成する酸化鉄も焼結性に寄与するためと推定される。比較品２は、鉄粉の添加量が少ない場合であるが、焼結性はやや改善されるものの、通電性が不十分であった。比較品３は、鉄粉量が多い場合であるが、焼結性に劣るだけではなく、耐食性も劣る結果となった。比較品４及び５は、ポルトランドセメントを含まない場合と３質量％と少ない場合であるが、この場合は焼結性が劣り、耐食性も余りよい結果とはならなかった。比較品６及び７は、ポルトランドセメントの添加量が大きすぎる場合であるが、耐食性に劣る結果となった。
上述のように、本発明品の直流電気炉用導電性熱間補修材の効果は明確である。
In Table 2 above, Comparative Product 1 was a case containing no iron powder, but it was not only poor in conductivity but also poor in sinterability. The reason why the sinterability is inferior is presumed to be that iron oxide produced by oxidation of iron also contributes to sinterability. Comparative product 2 was a case where the amount of iron powder added was small, but the sinterability was slightly improved, but the electrical conductivity was insufficient. Although the comparative product 3 is a case where there is much iron powder amount, it was not only inferior to sinterability, but also resulted in inferior corrosion resistance. Comparative products 4 and 5 were those containing no Portland cement and 3 mass%, but in this case, the sinterability was inferior and the corrosion resistance was not so good. Comparative products 6 and 7 were cases where the amount of Portland cement added was too large, but resulted in poor corrosion resistance.
As described above, the effect of the conductive hot repair material for a DC electric furnace according to the present invention is clear.
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| JP2007039255A (en) * | 2005-07-29 | 2007-02-15 | Kurosaki Harima Corp | Spraying material for repairing lining of steelmaking electric furnace and method for repairing lining of steelmaking electric furnace using the same |
| JP2007302521A (en) * | 2006-05-12 | 2007-11-22 | Kurosaki Harima Corp | Hot casting repair material |
| JP2008120635A (en) * | 2006-11-13 | 2008-05-29 | Shinagawa Refract Co Ltd | Hot spray repair material |
| JP2012126610A (en) * | 2010-12-16 | 2012-07-05 | Kurosaki Harima Corp | Baking repairing material |
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| CN115180894A (en) * | 2022-06-27 | 2022-10-14 | 中建八局第三建设有限公司 | Green brick for repairing ancient building wall and preparation method thereof |
| CN115180894B (en) * | 2022-06-27 | 2023-06-16 | 中建八局第三建设有限公司 | Green brick for repairing ancient building wall and preparation method thereof |
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