JP3683376B2

JP3683376B2 - Induction furnace lining material

Info

Publication number: JP3683376B2
Application number: JP09320797A
Authority: JP
Inventors: 喜久雄有賀
Original assignee: TYK Corp
Current assignee: TYK Corp
Priority date: 1997-03-26
Filing date: 1997-03-26
Publication date: 2005-08-17
Anticipated expiration: 2017-03-26
Also published as: JPH10267554A

Description

【０００１】
【発明の属する技術分野】
本発明は銅および銅合金の溶解や精錬を行う誘導炉の誘導炉用内張り材に関するものである。
【０００２】
【従来の技術】
従来、銅および銅合金等の金属の溶解、精錬を行う場合は主に黒鉛質のルツボを内装したルツボ炉が用いられているが、最近では多量の溶解や精錬が容易にできる作業効率が良く、品質の均一性や作業性の高い上作業環境が良い等の優位性を持つ誘導炉が品質管理上、作業効率上および作業環境上の諸問題より導入され、特に大型炉が急速に普及してきている。
【０００３】
誘導炉は外周部に電気誘導コイルを配設し、このコイルの内側に必要ならばコイル保護用のコイルセメントにより被覆層を備えさせ、その内側に湯モレセンサー、絶縁材、断熱材等を配設しその最内側に１層の耐火材壁（内張り材）を構築して使用されている。この内張り耐火壁の構築方法は小型炉では黒鉛ルツボを内装して炉本体とルツボとの間隙に乾式不定形耐火物（以下バック材と称する）を充填し施工されている。また大型炉では一般的には炉本体内に所定の壁厚さを持たせるように設計された鋼製の内型枠（以下フォ−マ−ト称する）を炉本体内に配設し、このフォーマーと炉本体との間隙部に乾粉状の不定形耐火物を投入した後、フォーマーの内側より振動を与えながら投入された不定形耐火物を加振充填させて施工して使用に供されている。この内張りされた底部や側壁の損傷が高いとか稼動面の汚れは炉の保全作業が多くなり炉の稼働率の低下が生じ工場全体の操業に支障をきたし大きな影響をもたらす。このため炉の長寿命化をはかるため、ここに用いられる耐火物は特に吟味された耐火材を用いて製造される耐火物が使用されている。
【０００４】
現在一般にはＳｉＣ５〜２０重量％、ＳｉＯ₂２〜２０重量％、Ａｌ₂Ｏ₃６０〜９３重量％の高アルミナ−炭化珪素質耐火物に必要ならば無水硼酸等の適宜の焼結助材を添加した乾式不定形耐火物が使用されているが、使用回数が進むにつれて内張り材の稼動面に操炉中に生成するスラグが徐々に付着堆積し、特に炉底部にその傾向は高く炉底が高くなり炉有効容積が減少し、時にはその減少率は容量で３０容量％にも達する。このため付着スラグ落し作業を余儀なくされる。このスラグ落し作業は付着スラグが銅の酸化物と銅金属が混在することにより高熱下でないと落しずらいことより極度な３Ｋ作業となると共に炉の稼働率も低下させることとなる。このような現状下でも作業効率、省力化や大型製品の需要増等により炉容は大型化へと進みこの現象更に増大し、ますますその作業は過酷の度を増し、更に保全作業頻度を多くしている。
【０００５】
これらの諸問題を解決し安定した繰炉ができて操業率が高く、ランニングコストが低く、良い環境下での作業を目指すため炉の内張り材の補修や解体、新規施工と云う３Ｋ作業の頻度が少なく且つ簡便で快適な作業となることが強く望まれているのが現状である。
【０００６】
【発明が解決しようとする課題】
本発明者等はこのような現状に鑑み高熱下でのスラグ落し作業という悪環境下での３Ｋ作業の軽減ができ、炉が正常で繰炉ができ、能力を十分発揮でき得る状態が維持でき、効率良く生産することが可能な誘導炉の内張り方法とその耐火物を提供することを技術的な課題とする。
【０００７】
【課題を解決するための手段】
本発明者等はこのような現状に鑑み、高熱下で炉の上部より覗き込むような状態で行なわれる３Ｋ作業であるスラグ付着物の除去作業をより軽減ができ、炉が正常で安定した操業ができて炉本来の能力を十分発揮できうる状態が維持できる方策を見い出すためにスラグ等付着物の付着、堆積の過程を種々の角度より調査を行った。その結果以下の順序で進行している。
【０００８】
▲１▼操炉中に生成するスラグは出湯時に上部より下部へ、底部へと付着して行く。 ▲２▼繰返えしされるため付着したスラグの成分が内張り材の組織中に浸入して表層に異質層（以下変質層と称する）を形成する。
▲３▼変質層はスラグとのなじみが良く付着し易すくなり付着度が増し堆積して行く。特に炉底部の内張り材の稼動面は湯温がやや低いため付着度合が高くなる。
▲４▼付着物とスラグ等となじみが良いので繰り返し繰り返し層状付着が進む。この付着物は銅の酸化物を主成分とし更には銅金属を混在することになり冷却すると展性の高い性状を有してくる。
▲５▼付着したスラグの除去作業は高熱下で行うがより高い堆積状況となった場合は炉を冷却させて行う。
【０００９】
このようにスラグの付着は、まづスラグが内張り材の組織内へ浸入し稼動層に変質層を形成させる。この生成された変質層はスラグや銅金属等とのなじみが良く容易に付着現象が発生し付着速度が早くなる。以後ほぼ同質のスラグが毎回接する。この両者はなじみ易く、この現象は繰返して層状堆積へと継がっていく。この付着堆積物中には銅の酸化物を主体とし銅金属が混在するため冷却させると銅の特性である展性が働き除去作業は非常に困難となり手間がかかる過酷な作業となるため除去が容易である高熱下での除去作業となり代表的な高熱下での３Ｋ作業がしいられる。
【００１０】
このような作業を続けるうちにも付着、堆積が進み炉容量が少なくなると共に溶解効率も大きく低下し、電気エネルギ−の浪費、生産性の低下により、ついには炉内張り材の取替えを余儀なくされ、その頻度が高くなっている等のその現状を知見し得た。
【００１１】
以上の如くスラグの付着、堆積は操業上、生産効率上大きな問題を生じている。現在最も多く一般に用いられている耐火物の成分組成はＳｉＯ₂１５重量％、ＳｉＣ１５重量％、Ａｌ₂Ｏ₃７０重量％の乾式不定形耐火物である。この耐火物により炉の底部および側壁部共施工されている。本発明者等は使用耐火材の特性を検討しさらに研究試験を重ねた結果、高シリカ−高炭化珪素質材とすることによりスラグの浸透、付着を大きく改善することを見いだし、炉の内張り材の材料構成を炭化珪素質材２５〜５５重量％、ムライト質材１０〜５５重量％、溶融石英質材５〜３５重量％、天然珪石質材１０〜３０重量％を含みこの四者の合量を９０重量％以上で構成された耐火材とすることにより材質的に大きな改善を見い出すことができた。
【００１２】
更にこの耐火物の性能を高めるため本耐火材に水と適宜の硬化剤を必要ならば、解膠剤を添加し混練後、あらかじめ炉底部の厚み３０mm以上で炉底部厚みの５０％迄の一体成形体とし１０００℃以下の熱処理を施こし気孔率を１５％以下とした緻密度の高い無目地状の成形体を誘導炉の底部に従来の乾式不定形耐火物によりまず一層打設した後、その上部に施工した後、従来と同じく鋼製型枠のフォーマーを挿入し所定の形態（型、厚み）に側壁部打撃加振して施工することにより目地部や組織内へのスラグ成分の浸入による変質層の生成、スラグの付着堆積を大きく改良させ現在の問題点の解決することができて安全な操業を行うことのできる手法をここに提供するものである。
【００１３】
（限定理由）
▲１▼炭化珪素質材、２５〜５５重量％
２５重量％以下ではスラグの耐浸入性や対付着効果が少ない。
５５重量％以上では５５重量％を越えてもその効果は大きく改善されることもなく材料コストが高くなる。
▲２▼ムライト質材、１０〜５５重量％
炭化珪素質材と混在材質となることにより組織の強化がはかられ物理的にも秀ぐれた特性を出すが１０重量％以下ではその効果が少なく、５５重量％以上となると緻密度が低下してスラグの浸透や表層での付着度が高くなる傾向を示す。▲３▼溶融石英質材、５〜３５重量％
溶解石英質材は耐熱スポ−リング性と焼結力を高める効果があるが５重量％以下では効果が小さく３５重量％を超えると耐食性が劣化するため。
▲４▼天然珪石質材、１０〜３０重量％
天然珪石質材は熱間での残存膨張性を高めて耐火材の使用中の受熱による内張り材の焼結収縮を改善し、亀裂の発生を防止するが１０重量％以下では効果が少なく、３０重量％を越えると使用中の組織の脆弱化が進むためである。
▲５▼炭化珪素質材、ムライト質材、溶融石英質材および天然珪石質材の合量が９０重量％以上この４者の合量が９０重量％以下となると本発明の内張り材の特質がそこなわれるためである。
▲６▼炉の底部に本発明の内張り材を厚み０mm以上で底部厚の５０％迄の厚さに施工する。
炉底部材の厚みが３０mm以下であると炉底部材の容損が進むと一部浮きあがり現象を含めて損傷が大きくなる。又炉底部の厚みの５０％以上の厚みまでは損傷には至らないためである。
【００１４】
【実施例】
実施例に用いた原料の化学成分値を表１に示す。
【表１】

実施例材の粒度測定値を表２に示す。
【表２】

実施例に用いた本発明材と比較例としての一般材の配合比率を表３に示す。
【表３】

本発明の実施例として表１、２に示す定められた材料を用いて表３▲１▼に示された配合比率に調整して、硬化剤、解膠剤としてリン酸ソ−ダ１重量％、水４重量％を添加し、混練後、粗、中粒子部材を混合、さらに混練後、振動台上で、加振脱泡を５分間行い、３０〜５０mm厚みの成形用原料を作成し、振動台上に２５０×１１４×６５mmの成形用石膏型を固定し、振動させながら石膏型内へこの成形用原料を順次投入して成形する。脱型後予備乾燥として３０〜５０℃２４時間乾燥後、５００℃１０時間の熱処理を行ない作製する。
【００１５】
比較品は表１、２に示す定められた材料を用いて表３▲２▼に示された配合比率に調整して、焼結助剤として無水硼酸１重量％添加し、ミキサ−にて乾式混合を行ない供試材とした。
【００１６】
成形方法として乾式振動充填による成形を行った。即ち振動台（振動数１８００回／分のユーラスモーターを設置する）上に２５０×４０×６５mmの鋼製枠内に１mm厚のステンレス製メタルケ−スを挿入した型を固定し、静圧にて５分間加振充填を行ない、この成形体を保形させるために８００℃で１０時間加熱した後、ステンレス製メタルケ−スより取り出して、試験体とした。
この試験結果を表４に示す。
【表４】

【００１７】
本発明の実用実施例として表４に示された本発明品を表４▲１▼の品質特性値試験材の製法と同じ様に硬化剤、解膠剤として１重量％のリン酸ソ−ダと４重量％の水を添加し、同じ様に原料を調製し振動台上に所定の炉底用ブロックの型を取付けて型自体を振動させながら調製された原料を徐々に投入しながら振動鋳込成形を行い２０時間養生後脱型し３０〜５０℃で２４時間予備乾燥をした後、１時間５０℃で昇温させながら、５００℃迄昇温後２４時間熱処理をほどこしてそれぞれ成形体を製作する。
【００１８】
この成形体を誘導炉の最炉底部に乾式不定形耐火物の比較品（表４▲２▼）を打設後あらかじめ１体成形された所定の形状炉底用ブロックをその上部に設置した後この上に所定の鋼製のフォーマーを配設する。このフォーマーと炉本体との間（所定の側壁内張り材の厚み）に底部ブロック材の下しき用材と同様、乾式不定形耐火物の比較材（表４▲２▼）を投入してフォーマーの内側より打撃を与えながら振動を加えて側壁部を加振充填を行ない築造し通電させ徐々に昇温しながら低温焼結させ不定形耐火物を硬化させながら溶解材を溶解するがこの初溶解時のみ炉壁の安定性と耐久性を高めるために通常の溶解温度よりも溶解温度を１００℃高い１３５０℃まで昇温２時間〜３時間保持し高温焼結を行い後温度調整をして使用した後は正規の操炉に入る。
【００１９】
実用実施例に用いた誘導炉の使用条件を次に示す。
炉の大きさ１０^T炉
溶解材銅
溶湯温度１２５０℃
【００２０】
尚本発明実用実施例の誘導炉用内張り用耐火物の構成を図１に従来方式を図２に示す。
実炉使用試験結果を表５に示す。
【表５】

【００２１】
【発明の効果】
表５に示されるように実用試験の結果では比較例に比べ本発明の態様（内張り材のライニング法）では炉底部でのスラグの付着開始時がおそく、かつ付着量も少ないことより付着したスラグの除去作業と比較例に比べほぼ同じ使用回数時では５回が２回少なくなり炉の冷却回数も２回と少なくなったことより炉の加熱、冷却頻度が減少し、炉壁の亀裂の発生発達が軽減、地金差しによる炉の寿命終了もなく良好なる効果が得られた。今回の試験結果では本発明の耐火物及び内張り材の構成であれば更に耐用寿命の延長が見込まれる。尚本発明の一番の課題であるスラグ付着の軽減と炉壁材の損傷を小さくし安全な操業、３Ｋ作業の改善については付着したスラグの除去作業、補修作業の頻度減少により１ch当りの作業頻度数０．０３４１ｃｈ／回が０．０１００ｃｈ／回となりその頻度比率は１００％か３０．８％となり、更に耐用寿命が１５４ｃｈが２０１ｃｈとなり１３０％の耐用向上につながって溶解効率の改善となり生産コスト引き下げにも大きな貢献をすることができ、その効果は絶大なものがある。
【図面の簡単な説明】
【図１】本発明の誘導炉用内張り材の下底方式実施態様を示す断面図である。
【図２】本発明の誘導炉用内張り材の入底方式の実施態様を示す断面図である。
【図３】従来の誘導炉用内張り材の実施態様を示す断面図である。
【符号の説明】
１従来の乾式不定形耐火物（底部）
２本発明による１体成形耐火物
３側壁部用乾式不定形耐火物
４本発明品と同材質による乾式不定形耐火物[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction furnace lining material for induction furnaces for melting and refining copper and copper alloys.
[0002]
[Prior art]
Conventionally, when melting and refining metals such as copper and copper alloys, a crucible furnace equipped with a graphite crucible has been used, but recently, a large amount of melting and refining is easy and work efficiency is high. Induction furnaces with superior quality uniformity, high workability and good work environment have been introduced due to quality control, work efficiency and work environment problems, especially large furnaces have been rapidly spreading. ing.
[0003]
In the induction furnace, an electric induction coil is arranged on the outer periphery, and if necessary, a coating layer is provided with coil cement for protecting the coil inside the coil, and a hot water sensor, insulating material, heat insulating material, etc. are arranged inside the coil. It is installed and constructed with a refractory material wall (lining material) on the innermost side. In the construction method of the lining refractory wall, in a small furnace, a graphite crucible is provided and a gap between the furnace main body and the crucible is filled with a dry amorphous refractory (hereinafter referred to as a back material). In large-sized furnaces, generally, a steel inner mold (hereinafter referred to as “format”) designed to have a predetermined wall thickness in the furnace body is disposed in the furnace body. After putting dry powder-like amorphous refractory into the gap between the former and the furnace body, the amorphous refractory that was thrown in while being vibrated from the inside of the former was vibrated and filled for use. ing. The damage to the bottom and side walls, which are lined up, and the contamination of the operation surface, increase the maintenance work of the furnace, which lowers the operation rate of the furnace and hinders the operation of the entire factory and has a great influence. For this reason, in order to prolong the life of the furnace, the refractory used here is a refractory manufactured using a particularly examined refractory material.
[0004]
Now commonly SiC5~20 wt%, SiO ₂ 2 to 20 wt%, Al ₂ O ₃ 60~93% by weight of high alumina - an appropriate sintering aids of boric anhydride, if necessary in the silicon carbide refractories The added dry amorphous refractory is used, but as the number of uses increases, the slag generated during the operation of the lining material gradually adheres and accumulates on the working surface of the lining material, and this tendency is particularly high at the bottom of the furnace. It becomes higher and the effective volume of the furnace decreases, and the rate of reduction sometimes reaches 30% by volume. For this reason, adhesion slag dropping work is forced. This slag dropping operation is an extreme 3K operation because the attached slag is difficult to drop unless it is under high heat due to a mixture of copper oxide and copper metal, and the operating rate of the furnace is also reduced. Even under such circumstances, the reactor capacity has been increased due to work efficiency, labor saving and increased demand for large products, and this phenomenon has further increased, and the work has become increasingly severe and the frequency of maintenance work has increased. doing.
[0005]
The frequency of 3K work such as repair and dismantling of furnace lining materials and new construction in order to solve these problems and achieve a stable furnace, high operating rate, low running cost, and work in a good environment At present, there is a strong demand for a simple and comfortable work with a small amount of work.
[0006]
[Problems to be solved by the invention]
In view of such a current situation, the present inventors can reduce the 3K work under the adverse environment of the slag dropping work under high heat, maintain the state where the furnace is normal and can perform the furnace, and can fully demonstrate the ability. It is a technical problem to provide a method for lining an induction furnace and its refractory that can be efficiently produced.
[0007]
[Means for Solving the Problems]
In view of the current situation, the present inventors can further reduce the slag deposit removal operation, which is a 3K operation performed in a state of looking into the top of the furnace under high heat, so that the furnace operates normally and stably. In order to find a way to maintain the state that can fully demonstrate the original capacity of the furnace, the process of depositing and depositing slag and other deposits was investigated from various angles. As a result, it proceeds in the following order.
[0008]
(1) Slag generated during the operation of the furnace adheres from the top to the bottom and from the bottom to the bottom during hot water. {Circle around (2)} The slag component adhering to the inside penetrates into the structure of the lining material to form a heterogeneous layer (hereinafter referred to as an altered layer) on the surface layer.
(3) The altered layer has a good affinity with the slag and becomes easy to adhere, and the degree of adhesion increases and accumulates. In particular, the operating surface of the lining material at the bottom of the furnace has a high degree of adhesion because the hot water temperature is slightly low.
{Circle around (4)} Since the adhesion between the deposit and the slag is good, the layered deposition repeatedly proceeds repeatedly. This deposit contains a copper oxide as a main component and further contains copper metal, and when cooled, has a highly malleable property.
(5) The work for removing the adhering slag is performed under high heat, but when the deposition condition becomes higher, the furnace is cooled.
[0009]
In this way, the slag adheres, firstly, the slag enters into the structure of the lining material and forms an altered layer in the working layer. The generated deteriorated layer has a good affinity with slag, copper metal, etc., and the adhesion phenomenon easily occurs, and the adhesion speed is increased. Since then, slag of almost the same quality will contact each time. Both of these are easy to adapt, and this phenomenon continues to layer deposition. This deposit is mainly composed of copper oxide and contains copper metal, so if it is cooled, the malleability, which is a characteristic of copper, works and the removal work becomes very difficult and laborious. This is an easy removal operation under high heat, and a typical high heat 3K operation is performed.
[0010]
While continuing such work, the adhesion and deposition progressed and the furnace capacity decreased and the melting efficiency was greatly reduced. Waste of electric energy and a decrease in productivity led to forced replacement of the furnace lining material. I was able to find out the current situation, such as the frequency of the increase.
[0011]
As described above, the adhesion and accumulation of slag cause a big problem in operation and production efficiency. Component composition of the refractory used in the currently most commonly SiO ₂ 15 wt%, SiC15 wt%, Al ₂ O ₃ 70 wt% of the dry monolithic refractory. This refractory is used for both the bottom and side walls of the furnace. As a result of investigating the characteristics of the refractory material used and conducting further research tests, the present inventors have found that the penetration and adhesion of slag can be greatly improved by using a high silica-high silicon carbide material, and the furnace lining material. The total amount of these four components, including 25 to 55% by weight of silicon carbide material, 10 to 55% by weight of mullite material, 5 to 35% by weight of fused silica material, and 10 to 30% by weight of natural siliceous material By using as a refractory material composed of 90% by weight or more, a great improvement in material properties could be found.
[0012]
Furthermore, if it is necessary to add water and an appropriate curing agent to the refractory material in order to enhance the performance of the refractory, after adding a deflocculant and kneading, the furnace bottom thickness of 30 mm or more and up to 50% of the furnace bottom thickness are integrated in advance. After forming a compact body with a high density and having a porosity of 15% or less by heat treatment at 1000 ° C. or less as a molded body, it was first placed in the bottom of the induction furnace with a conventional dry amorphous refractory, After the construction on the upper part, the steel mold former is inserted and the side wall is struck and shaken into the specified form (mold, thickness). It is intended to provide a technique that can greatly improve the generation of altered layers and slag deposits, and solve the current problems and enable safe operation.
[0013]
(Reason for limitation)
(1) Silicon carbide material, 25 to 55% by weight
If it is 25% by weight or less, the penetration resistance and anti-adhesion effect of the slag are small.
If it exceeds 55% by weight, the effect is not greatly improved even if it exceeds 55% by weight, and the material cost increases.
(2) Mullite material, 10-55% by weight
By combining silicon carbide and mixed materials, the structure is strengthened and the physical properties are excellent. However, the effect is less at 10% by weight or less, and the density decreases at 55% by weight or more. The tendency of slag penetration and surface adhesion is high. (3) Fused quartz material, 5 to 35% by weight
The fused quartz material has the effect of increasing the heat resistance and sintering power, but the effect is small at 5% by weight or less, and the corrosion resistance deteriorates when it exceeds 35% by weight.
(4) Natural siliceous material, 10-30% by weight
Natural siliceous material improves the residual expansibility in the hot and improves the sintering shrinkage of the lining material due to heat reception during the use of the refractory material, and prevents cracking, but is less effective at 10 wt% or less, 30 This is because when the weight percentage is exceeded, the organization in use becomes more vulnerable.
(5) When the total amount of silicon carbide material, mullite material, fused quartz material and natural siliceous material is 90% by weight or more and the total amount of these four members is 90% by weight or less, the characteristics of the lining material of the present invention are This is to be done there.
(6) The lining material of the present invention is applied to the bottom of the furnace to a thickness of 0 mm or more and up to 50% of the thickness of the bottom.
When the thickness of the furnace bottom member is 30 mm or less, the damage including the partially floating phenomenon increases as the loss of the furnace bottom member proceeds. Moreover, it is because damage is not caused to the thickness of 50% or more of the thickness of the furnace bottom.
[0014]
【Example】
Table 1 shows the chemical component values of the raw materials used in the examples.
[Table 1]

Table 2 shows the measured particle sizes of the example materials.
[Table 2]

Table 3 shows the blending ratios of the present invention material used in the examples and the general material as a comparative example.
[Table 3]

As an example of the present invention, using the specified materials shown in Tables 1 and 2 and adjusting the blending ratio shown in Table 3 (1), 1% by weight of soda phosphate as a curing agent and peptizer 4% by weight of water was added, and after kneading, the coarse and medium particle members were mixed, and after kneading, the mixture was subjected to vibration and defoaming for 5 minutes on a vibration table to produce a molding raw material having a thickness of 30 to 50 mm. A molding gypsum mold of 250 × 114 × 65 mm is fixed on a vibration table, and the molding raw materials are sequentially charged into the gypsum mold while being vibrated and molded. After demolding, as a preliminary drying, drying is performed at 30 to 50 ° C. for 24 hours, and then heat treatment at 500 ° C. for 10 hours is performed.
[0015]
The comparative product was adjusted to the blending ratio shown in Table 3 (2) using the specified materials shown in Tables 1 and 2, 1% by weight of anhydrous boric acid was added as a sintering aid, and dry-mixed with a mixer. Mixing was performed to obtain a test material.
[0016]
Molding by dry vibration filling was performed as a molding method. In other words, a mold in which a 1 mm thick stainless steel metal case is inserted into a 250 x 40 x 65 mm steel frame is fixed on a vibration table (a Eurus motor with a frequency of 1800 rotations / min) and static pressure is applied. After 5 minutes of vibration filling, the molded body was heated at 800 ° C. for 10 hours to retain the shape, and then taken out from a stainless steel metal case to obtain a test body.
The test results are shown in Table 4.
[Table 4]

[0017]
As a practical example of the present invention, the product of the present invention shown in Table 4 was used in the same manner as the quality characteristic value test material shown in Table 4 (1). And 4% by weight of water, prepare the raw material in the same way, attach a predetermined furnace bottom block mold on the shaking table and vibrate the mold itself while gradually adding the prepared raw material to vibration casting After molding for 20 hours, demolding, pre-drying at 30-50 ° C. for 24 hours, raising the temperature to 50 ° C. for 1 hour, raising the temperature to 500 ° C., and then subjecting each molded body to a heat treatment for 24 hours. To manufacture.
[0018]
After placing this compact in the induction furnace at the bottom of the induction furnace with a dry amorphous refractory comparative product (Table 4 (2)), and then placing a pre-shaped furnace bottom block on the top of the molded body. A predetermined steel former is disposed thereon. The dry amorphous refractory comparison material (Table 4 (2)) is inserted between the former and the furnace body (thickness of the specified side wall liner) as well as the bottom block material. Applying vibration while giving more impact, filling the side wall with vibration and filling, energizing it, gradually raising the temperature and sintering at low temperature to cure the amorphous refractory, melting the melting material, but only at the first melting In order to increase the stability and durability of the furnace wall, the melting temperature is raised to 1350 ° C., which is 100 ° C. higher than the normal melting temperature, held for 2 to 3 hours, and after high temperature sintering is performed and the temperature is adjusted and used Enters a regular furnace.
[0019]
The use conditions of the induction furnace used in the practical examples are as follows.
Size of furnace 10 ^T melting material Copper melt temperature 1250 ° C
[0020]
The configuration of the refractory for the induction furnace lining according to the practical example of the present invention is shown in FIG. 1, and the conventional system is shown in FIG.
The actual furnace use test results are shown in Table 5.
[Table 5]

[0021]
【The invention's effect】
As shown in Table 5, in the result of the practical test, in the aspect of the present invention (lining material lining method) compared to the comparative example, the slag adhered at the start of the slag at the bottom of the furnace is slow and the amount of adhesion is small. When the number of times of use is almost the same as that of the comparative example, the number of times of use is reduced by 2 times and the number of times of cooling of the furnace is reduced to 2 times. The development was reduced, and a good effect was obtained without the end of the life of the furnace due to the metal bar. In this test result, the service life is expected to be further extended if the refractory and the lining material of the present invention are configured. The most important issue of the present invention is the reduction of slag adhesion and the safe operation by reducing damage to the furnace wall material. The improvement of 3K work is the work per channel by removing the adhered slag and reducing the frequency of repair work. The frequency of 0.0341ch / time is 0.0100ch / time, and the frequency ratio is 100% or 30.8%. Furthermore, the service life is 154ch, which is 201ch, leading to improved service life of 130%, improving dissolution efficiency, and production cost. It can make a big contribution to the reduction, and the effect is tremendous.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a lower-bottom system embodiment of an induction furnace lining material according to the present invention.
FIG. 2 is a cross-sectional view showing an embodiment of a bottoming system for an induction furnace lining material according to the present invention.
FIG. 3 is a cross-sectional view showing an embodiment of a conventional lining material for an induction furnace.
[Explanation of symbols]
1 Conventional dry amorphous refractories (bottom)
2 One-piece molded refractory according to the present invention 3 Dry amorphous refractory for side wall 4 Dry amorphous refractory made of the same material as the present invention

Claims

Silicon carbide material 25-55 wt%, mullite material 10-55 wt%, fused quartz material 5-35 wt%, natural siliceous material 10-30 wt%, the total amount of these four is 90 wt% or more A lining corresponding to up to 50% of the thickness of the bottom of the induction furnace at least 30 mm in the induction furnace using water, an appropriate curing agent and, if necessary, a peptizer added to the refractory material composed of The part is molded using a mold, and after demolding, heat treatment at 1000 ° C. or lower is performed, and an integrally molded fixed refractory having a porosity of 15% or less is used. After placing with silicon-type dry amorphous refractory, and constructing it as the furnace bottom working layer on the top, insert steel mold into the furnace body and construct the sidewall with dry amorphous material An induction furnace lining material characterized by having a bottom multi-layer structure.