JP3646125B2 - High-temperature property testing equipment for electric furnace raw materials for alloy iron production - Google Patents

High-temperature property testing equipment for electric furnace raw materials for alloy iron production Download PDF

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JP3646125B2
JP3646125B2 JP2000240250A JP2000240250A JP3646125B2 JP 3646125 B2 JP3646125 B2 JP 3646125B2 JP 2000240250 A JP2000240250 A JP 2000240250A JP 2000240250 A JP2000240250 A JP 2000240250A JP 3646125 B2 JP3646125 B2 JP 3646125B2
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graphite rod
electric furnace
temperature
raw material
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JP2002060853A (en
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義浩 宮内
英樹 秋本
嘉弘 木津
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日本電工株式会社
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Priority to FR0110432A priority patent/FR2812944B1/en
Priority to NO20013841A priority patent/NO20013841L/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、電気炉で溶融・還元される鉱石、特にマンガン系合金鉄の製造に供されるマンガン含有鉱石の高温性状を測定し、さらに前記鉱石が電気炉装入原料として適しているかどうかを評価することのできる装置に関する。
【０００２】
【従来の技術】
マンガン系合金鉄は、原料鉱石と炭素系還元剤とを電気炉に装入し、これら装入物中に電極を挿入して通電加熱して高温状態とし、原料鉱石と炭素系還元剤とを反応させることによって製造する。この際、電気炉の操業を安定維持して原料原単位および電力原単位を低く抑えることが必要である。
【０００３】
電気炉操業の安定性には種々の要因が関係するが、中でも原料鉱石の高温性状は、その還元過程における電気伝導性、発生ガスの通気性、該鉱石から生成する溶融スラグの粘性等により、電気炉操業の安定性に直接影響する。なかでも還元過程での電気伝導性が極めて重要である。すなわち、電気炉精錬の場合は、装入原料を電極間の抵抗加熱により加熱して原料鉱石を溶融し、さらに金属状態への還元温度まで昇温する必要があるが、原料鉱石の電気抵抗が小さいと電極直下および周辺の温度を速やかに上げることができず、還元反応が停滞するばかりでなく、生成したスラグの温度が上がらず、スラグの流動性が低下するためメタルとスラグの分離性が悪化することになる。このように、原料鉱石の電気伝導性が電気炉操業に及ぼす影響は極めて大きい。
【０００４】
したがって、例えば、新しい鉱石が入荷した場合にその原料鉱石の高温性状を的確に知ることが必要である。この要求に対し、従来は、過去の経験とその鉱石の化学成分等から原料鉱石の電気伝導性等の高温性状を推定する方法がとられていた。しかし、高温性状に影響をおよぼす要因には未知のものも多く、そのため、装入鉱石の電気伝導性が推定と異なり、電気炉の安定操業が阻害される事態に至ることも多く、操業上のリスクが大きかった。
【０００５】
このような問題に対処するため、特許第2935611号公報には、高温荷重軟化試験を用いた鉱石原料の高温性状の評価方法が提案されている。また、例えば、「フェアロイ，Vol．21，No2，ｐ.63-68（1972）」には、マンガン鉱石などフェロマンガン製造用原料の熱間電気抵抗を測定した結果が報告されている。
【０００６】
【発明が解決しようとする課題】
しかしながら、前者の提案は、原料鉱石の軟化溶融挙動を把握するものであり、電気炉操業を左右する原料鉱石の電気伝導性を正確に評価できず、その結果に基づいて電気炉操業を行った場合、必ずしも充分な安定性が得られなかった。また、後者の手段は、鉱石が未だ軟化・溶融しない温度範囲である1000℃までの領域における鉱石の電気抵抗を測定するものであり、鉱石が溶融し、還元される温度領域の電気伝導度を与えることができず、操業上の指標になり得ないものであった。さらに、1000℃を超え、溶融・還元される状態に至る期間では、原料鉱石は固相状態では膨張し、軟化・溶融に伴い収縮する。そのような状態における原料鉱石の電気伝導性に係る情報を的確に与える手段は未だ提案されていない。
【０００７】
本発明は、かかる1000℃を超え、溶融・還元される状態に至る期間における原料鉱石の高温性状、特に電気伝導性に係る正確なデータを与えることのできる合金鉄製造用電気炉原料の高温性状試験装置を提案することを目的とし、特に還元温度域での電気炉内の状況に近似した状態で、原料鉱石の電気伝導性を測定することのできる装置を提案することを目的とする。
【０００８】
【課題を解決するための手段】
本発明の合金鉄製造用電気炉原料の高温性状試験装置は、合金鉄製造用の電気炉原料から調製された試料を収容する試料収容室と、前記試料を少なくとも1500℃まで上昇させる加熱装置と、前記加熱装置により加熱される試料を加圧しながら該試料の電気抵抗、層厚ならびに温度を測定する高温性状測定装置と、を備えている。
【０００９】
上記合金鉄製造用電気炉原料の高温性状試験装置の試料収容室は、黒鉛るつぼと該黒鉛るつぼ内に嵌挿された耐火物スリーブとからなる試料装入容器と該試料装入容器を取り囲むアルミナチューブからなり、前記アルミナチューブには底部から中空黒鉛棒、上部から中実黒鉛棒が差し込まれており、前記中空黒鉛棒はその上端を前記黒鉛るつぼの底部に接して前記黒鉛るつぼを支持し、前記中実黒鉛棒はその下端を前記耐火物スリーブを通して試料上面に接して試料を加圧し、かつ、前記中空黒鉛棒と前記中実黒鉛棒には電気抵抗測定装置が接続されていることを好適とする。
【００１０】
また、前記中実黒鉛棒には、該中実黒鉛棒の下端部から前記黒鉛るつぼの内底面に至る距離を計測する試料層厚測定装置が設けられていることを好適とする。また、前記中実黒鉛棒には、上端から下端近傍に至る細孔が穿たれ、該細孔には熱電対が挿入されていることを好適とし、さらに、前記中実黒鉛棒には、試料加圧調整手段が設けられていることを好適とする。
【００１１】
さらに、前記中空黒鉛棒には、外部から雰囲気ガスを受け入れるガス供給管と、該雰囲気ガスをアルミナチューブ内に導入するガス導入部を設けるのがよい。
【００１２】
【発明の実施の形態】
以下、本発明の合金鉄製造用電気炉原料の高温性状試験装置の構成をその動作とともに具体的に説明する。図１は、本発明の合金鉄製造用電気炉原料の高温性状試験装置の１例の全体構成を示す概略図である。ここに示すように、本発明の合金鉄製造用電気炉原料の高温性状試験装置は、合金鉄製造用の電気炉原料から調製された試料Sを収容する試料収容室11と、前記試料を少なくとも1500℃まで上昇させる加熱装置21と、前記加熱装置21により加熱される試料Sを加圧しながら該試料Sの電気抵抗、層厚ならびに温度を測定する高温性状測定装置40と、を備えている。
【００１３】
試料収容室11は、例えば、黒鉛るつぼ12とその中に嵌挿された耐火物スリーブ13とからなる試料装入容器17をアルミナチューブ14で取り囲んで作られている。このアルミナチューブ14には底部から中空黒鉛棒15、上部から中実黒鉛棒16が差し込まれている。このうち、中空黒鉛棒15はその上端が前記黒鉛るつぼ12の底部に接して下方から前記黒鉛るつぼを支持し、一方、中実黒鉛棒16はその下端を前記耐火物スリーブ13を通して試料S上面に接してこれを圧下するようになっている。
【００１４】
そして、中空黒鉛棒15および中実黒鉛棒16には電気端子18、19が設けられ、これらを介して電気抵抗測定装置41に接続されている。したがって、中空黒鉛棒15−黒鉛るつぼ12−試料S−中実黒鉛棒16は１本の導電体となり、しかも、試料Sは絶縁体である耐火物スリーブ13によりその側面が黒鉛るつぼから電気的に絶縁されているので、試料Sの層厚方向の電気抵抗Rを測定することができる。なお、試料Sが装入されていない状態での、中空黒鉛棒15−黒鉛るつぼ12−中実黒鉛棒16間の電気抵抗（試料S以外の抵抗）は、本例の場合、0.02Ωであり、無視できる程度である。電気抵抗測定装置の形式は特に問わないが、交流電流（例えば1kHz）の下で電気抵抗測定を行うようにするのが望ましい。これは、直流電流を使用すると、試料が溶融して液体となったとき、イオン伝導体となり物質移動が起るため、正確な数値が読み取れなくなるからである。また、耐火物スリーブ13は少なくとも1500℃までの温度、できれば1600℃でも軟化溶融しないことは勿論のこと、試料と反応しない材質を選択するのがよい。
【００１５】
上記により測定される試料Sの電気抵抗値Rから試料の電気伝導度κを求めるには、試料Sの層厚hを求めなければならず、そのため試料層厚測定装置45を設ける。これには、中実黒鉛棒16の位置を利用するのが便利である。具体的には、中実黒鉛棒16の下端を試料Sの上面に接触せしめ、一方その上端には試料の上面位置を測定できる高さ計を設け、黒鉛るつぼ12の内底面から中実黒鉛棒16の下端までの距離を試料層厚hとして測定できるようにする。このように構成される試料高さ測定装置45は試料Sの上面位置変化を検知するのに公知の作動トランスを用い、試料Sが装入されていない状態で中実黒鉛棒16の下端を黒鉛るつぼ12の内底面に接触させ、そのときの高さを0とし、これを基準として装入された試料層厚hを決定すればよい。なお、試料断面積は、耐火物スリーブ13の内径から計算できる。
【００１６】
高温における鉱石試料の電気抵抗などの測定値は、試料温度とともに記録されなければならない。そのため、本発明の合金鉄製造用電気炉原料の高温性状試験装置には、試料Sの温度を測定する手段として試料温度測定装置47を設けなければならない。その手段は例えば、黒鉛るつぼ12、耐火物スリーブ13を通して試料中に差し込んだ熱電対によることもできるが、前記中実黒鉛棒16にその上端から下端近傍に至る細孔48を穿ち、この細孔48の底部に熱電対を挿入し、これにより測定された細孔48の底部の温度を試料Sの温度として計測するのが便利である。
【００１７】
また、本発明の合金鉄製造用電気炉原料の高温性状試験装置では、試料の温度が1000℃を超え、少なくとも1500℃に達するようにする必要がある。これは、本発明者が先に提案した鉱石の評価方法、すなわち、1300〜1500℃の間において、みかけの電気伝導度が、炭素系還元剤のみかけ電気伝導度を上回る原料鉱石を電気炉装入適正鉱石と判定する方法を採用する場合には、少なくとも1500℃の加熱温度が必要になるからである。なお、迅速かつ確実に原料鉱石の高温性状評価試験を行うためには、本発明装置の加熱能力は少なくとも1600℃を超えるものとするのがよい。
【００１８】
この温度域において、原料鉱石は固相状態では温度の上昇と共に膨張し、軟化・溶融に伴い収縮する。したがって、試料Sを測定期間中、例えば一定の圧力で圧下して上記軟化・溶融に基づく収縮を補償できるようにしなければならない。そのための手段として、前記中実黒鉛棒16を介して試料Sに適当な圧力が加わるようにする。具体的には、中実黒鉛棒16の上端近傍に、例えば、適当な分銅などを載荷できる加圧装置61を設け、試料Sに調整された圧力を加えられるようにするのがよい。
【００１９】
さらに、試料Sの加熱、溶融さらには還元の各過程における雰囲気を調整するために、雰囲気ガスをガス導入管65から中空黒鉛棒15を経由し、ガス導入部69からアルミナチューブ14内へ導入し、試料収容室を雰囲気ガスで満たした後、ガス排出管68から外部に排出される構造を有している。
【００２０】
また、試料S中に雰囲気ガスを吹き込む場合には、図３に示すように、黒鉛るつぼ12の下端に多数の雰囲気ガス導入口66を設け、これに中空黒鉛棒15を接続させることもできる。この場合には、耐火物スリーブ13と中空黒鉛棒16との間には僅かなすきま67が必要である。なお、雰囲気ガスとしては不活性ガス、例えばN2ガスを使用し得るほか、任意のCO、CO2、H2混合ガスを用いることができる。このような構造を有することによって電気炉内におけるMn含有鉱石の間接還元反応を再現しながら鉱石の電気伝導度を測定することができる。
【００２１】
本発明の合金鉄製造用電気炉原料の高温性状測定装置には、上記試料収容室11内の温度を少なくとも1500℃にまで加熱するために、例えばSiC系の発熱体などの加熱装置21を設ける。さらに、これら試料収容室11および加熱装置21を断熱構造体31により取り囲む。なお、断熱構造体31は全体を鉄皮32でカバーし、全体を補強するとともに、該鉄皮さらにはその内部に巻かれた断熱構造体31を介して加熱装置21、中空黒鉛棒15、ひいては試料収容室11を固定するのがよい。
【００２２】
上記装置により、試料Sを加熱しながらその温度、電気抵抗（R）、試料層厚（h）を計測することができる。さらにこれらの測定結果に基づき、Aを試料断面積として、電気伝導度κを、
κ＝h/（A・R）
により求めることができる。なお、上記電気抵抗（R）は、鉱石の絶対的な電気抵抗値ではなく、電気炉操業条件等を加味した条件の下での見かけの電気抵抗値であり、したがって電気伝導度κも見かけの電気伝導度である。
【００２３】
測定された温度、電気伝導度κに基づき電気炉装入鉱石の評価をすることができる。その手法はすでに本発明者が特願平11-350817号において提案しているものであるが、1300〜1500℃の間において、電気伝導度が炭素系還元剤の電気伝導度を上回る原料鉱石を電気炉装入適正鉱石と判定するものである。この判定をするためには、図４に示すように温度−見かけ電気伝導度の関係曲線を描き、これをコークス単味の電気伝導度曲線と比較する。
【００２４】
そのため、本発明装置においては、例えば、電気抵抗測定装置41、試料温度測定装置47、試料層厚測定装置45から各測定結果を得、これらに基づき電気伝導度を演算するとともに、コークス単味の電気伝導度と比較する電気伝導度演算装置51を備えることもできる。
【００２５】
本発明装置による鉱石の性状測定条件は、電気炉の操業条件に合わせて任意に選ぶことができるが、代表例を示すと以下の如くである。
試料鉱石の粒度：3〜5mm
試料鉱石の層厚：50mm
試料断面積：6.15cm2
試料鉱石への荷重：20kPa
電気抵抗測定周波数：1kHz
【００２６】
また、試料鉱石の調整に当たっては、評価対象である原料鉱石等に粒度3〜5mmのコークスを質量比で10%混合したものを用い、電気炉内の状態に近似させるのがよい。昇温速度は1000℃までは10℃/min、それ以上では3℃/minとするのがよい。さらに、測定中は試料収容室11内の黒鉛材質の酸化防止のために、不活性ガスを流しておくのがよい。これらの測定条件は、比較対象であるコークスの場合にも適用する。
【００２７】
図４は、本発明に係る装置を用いて各種原料鉱石（L、M、N）およびコークスの高温性状を測定した結果であり、各種原料鉱石およびコークスの見かけ電気伝導度と温度との関係図である。この結果より明らかなように、鉱石Lは、鉱石MあるいはNに較べて1300〜1500℃の還元温度域で見かけ電気伝導度が高い特徴を有している。いいかえれば、鉱石Lは、鉱石MあるいはNに較べて電気伝導特性が劣っている。そのため実操業において鉱石Lを多量配合すると、電極が浮いた状態となって、電力負荷が掛かりにくくなる現象が現れ、各種原単位およびMn収率が悪化した。これに対し、鉱石MあるいはNを多量配合した場合には、炉内装入原料の電気伝導度が適性範囲にあるため良好な操業を維持できた。
【００２８】
このように、本発明装置を用いて原料鉱石を評価した結果は、電気炉の操業実績とよい一致を示し、したがって、本発明装置が電気炉内の状態を精度よくシミュレートしていることが分かる。
【００２９】
本発明の試験装置により、マンガン系合金鉄を製造する電気炉内での状態をシミュレートした条件下で電気炉操業を左右する原料鉱石の電気伝導度を的確に評価できるようになった。その結果、原料鉱石の配合を適正に決定することが可能となり、電気炉の操業の安定、Mn収率の向上、電力原単位の低減など操業コストの低減に寄与する。
【図面の簡単な説明】
【図１】 本発明の合金鉄製造用電気炉原料の高温性状試験装置の全体構成を示す概略図である。
【図２】 図１のＡ−Ａ矢視断面図である。
【図３】 本発明の合金鉄製造用電気炉原料の高温性状試験装置の試料装入容器の拡大図である。
【図４】 本発明に係る装置を用いて各種原料鉱石およびコークス単味の高温性状を測定した結果であり、各種原料鉱石の見かけ電気伝導度と温度との関係図である。
【符号の説明】
11：試料収容室
12：黒鉛るつぼ
13：耐火物スリーブ
14：アルミナチューブ
15：中空黒鉛棒
16：中実黒鉛棒
17：試料装入容器
18、19：電気端子
21：加熱装置
31：断熱構造体
40：高温性状測定装置
41：電気抵抗測定装置
45：試料層厚測定装置
47：試料温度測定装置
51：電気伝導度演算装置
61：加圧装置
65：雰囲気ガス導入管
66：雰囲気ガス導入口
67：すきま
68：ガス排出管
69：ガス導入部
S：試料[0001]
BACKGROUND OF THE INVENTION
The present invention measures the high-temperature properties of ores that are melted and reduced in an electric furnace, particularly manganese-containing ores used for the production of manganese-based alloy iron, and further determines whether the ores are suitable as raw materials for electric furnaces. It relates to a device that can be evaluated.
[0002]
[Prior art]
Manganese-based alloy iron is charged with raw ore and carbon-based reducing agent in an electric furnace, and an electrode is inserted into these charges and heated by heating to a high temperature state. Produced by reacting. At this time, it is necessary to keep the operation of the electric furnace stable and keep the raw material intensity and the power intensity low.
[0003]
Various factors are related to the stability of the electric furnace operation, but the high-temperature properties of the raw ore are the electric conductivity in the reduction process, the gas permeability, the viscosity of the molten slag generated from the ore, etc. Directly affects the stability of electric furnace operation. In particular, electrical conductivity in the reduction process is extremely important. That is, in the case of electric furnace refining, it is necessary to heat the charged raw material by resistance heating between the electrodes to melt the raw material ore and further raise the temperature to the reduction temperature to the metal state. If it is small, the temperature immediately below and around the electrode cannot be quickly raised, and not only the reduction reaction stagnate, but also the temperature of the generated slag does not rise, and the fluidity of the slag decreases, so the metal and slag can be separated. It will get worse. As described above, the influence of the electric conductivity of the raw material ore on the operation of the electric furnace is extremely large.
[0004]
Therefore, for example, when new ore arrives, it is necessary to accurately know the high-temperature properties of the raw ore. In response to this requirement, conventionally, a method has been adopted in which high-temperature properties such as electrical conductivity of raw ore are estimated from past experience and chemical composition of the ore. However, there are many unknown factors that affect high-temperature properties.Therefore, unlike the estimation, the electric conductivity of the charged ore often leads to a situation where the stable operation of the electric furnace is hindered. The risk was great.
[0005]
In order to deal with such problems, Japanese Patent No. 2935611 proposes a method for evaluating the high temperature properties of ore raw materials using a high temperature load softening test. Further, for example, “Fairroy, Vol. 21, No. 2, p. 63-68 (1972)” reports the results of measuring the hot electrical resistance of raw materials for producing ferromanganese such as manganese ore.
[0006]
[Problems to be solved by the invention]
However, the former proposal is to grasp the softening and melting behavior of the raw ore, and the electric conductivity of the raw ore that affects the electric furnace operation could not be accurately evaluated, and the electric furnace operation was performed based on the result. In some cases, sufficient stability was not always obtained. The latter method measures the electrical resistance of the ore in the region up to 1000 ° C, which is the temperature range in which the ore has not yet softened or melted. The electrical conductivity in the temperature region where the ore melts and is reduced is measured. It could not be given and could not be an operational index. Furthermore, in a period exceeding 1000 ° C. and reaching a state where it is melted / reduced, the raw material ore expands in the solid phase and contracts with softening / melting. No means has yet been proposed for accurately giving information on the electrical conductivity of the raw ore in such a state.
[0007]
The present invention is a high-temperature property of the raw material ore for a period of time exceeding 1000 ° C. and reaching a state of being melted and reduced, in particular, high-temperature property of an electric furnace raw material for producing iron alloy capable of giving accurate data on electrical conductivity. The purpose is to propose a test apparatus, and in particular, to propose an apparatus that can measure the electrical conductivity of raw ore in a state that approximates the condition in the electric furnace in the reduction temperature range.
[0008]
[Means for Solving the Problems]
A high-temperature property testing apparatus for an electric furnace raw material for producing an iron alloy according to the present invention includes a sample containing chamber for containing a sample prepared from an electric furnace raw material for producing an alloy iron, and a heating device for raising the sample to at least 1500 ° C. And a high temperature property measuring device for measuring the electrical resistance, the layer thickness and the temperature of the sample while pressurizing the sample heated by the heating device.
[0009]
The sample storage chamber of the high-temperature property testing apparatus for the electric furnace raw material for producing the alloy iron includes a sample charging container composed of a graphite crucible and a refractory sleeve fitted into the graphite crucible, and alumina surrounding the sample charging container. A hollow graphite rod is inserted into the alumina tube from the bottom, and a solid graphite rod is inserted from the top into the alumina tube, and the hollow graphite rod supports the graphite crucible with its upper end in contact with the bottom of the graphite crucible, Preferably, the solid graphite rod presses the sample with its lower end in contact with the upper surface of the sample through the refractory sleeve, and an electrical resistance measuring device is connected to the hollow graphite rod and the solid graphite rod. And
[0010]
The solid graphite rod is preferably provided with a sample layer thickness measuring device for measuring a distance from a lower end portion of the solid graphite rod to the inner bottom surface of the graphite crucible. Further, the solid graphite rod is preferably provided with pores extending from the upper end to the vicinity of the lower end, and a thermocouple is inserted into the pore, and the solid graphite rod further includes a sample. It is preferable that a pressure adjusting means is provided.
[0011]
Further, the hollow graphite rod is preferably provided with a gas supply pipe for receiving an atmospheric gas from the outside and a gas introduction part for introducing the atmospheric gas into the alumina tube.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the high-temperature property testing apparatus for the electric furnace raw material for producing iron alloy according to the present invention will be specifically described together with the operation thereof. FIG. 1 is a schematic view showing an overall configuration of an example of a high-temperature property testing apparatus for an electric furnace raw material for producing alloy iron according to the present invention. As shown here, the high-temperature property testing apparatus for electric furnace raw material for producing iron alloy according to the present invention includes a sample containing chamber 11 for containing a sample S prepared from an electric furnace raw material for producing iron alloy, and at least the sample. A heating device 21 that raises the temperature to 1500 ° C. and a high-temperature property measuring device 40 that measures the electrical resistance, layer thickness, and temperature of the sample S while pressurizing the sample S heated by the heating device 21 are provided.
[0013]
The sample storage chamber 11 is formed, for example, by surrounding a sample charging container 17 composed of a graphite crucible 12 and a refractory sleeve 13 inserted therein with an alumina tube 14. A hollow graphite rod 15 is inserted into the alumina tube 14 from the bottom, and a solid graphite rod 16 is inserted from the top. Among these, the hollow graphite rod 15 has its upper end in contact with the bottom of the graphite crucible 12 and supports the graphite crucible from below, while the solid graphite rod 16 has its lower end on the upper surface of the sample S through the refractory sleeve 13. It is designed to touch and reduce this.
[0014]
The hollow graphite rod 15 and the solid graphite rod 16 are provided with electrical terminals 18 and 19 and connected to the electrical resistance measuring device 41 through these. Therefore, the hollow graphite rod 15-graphite crucible 12-sample S-solid graphite rod 16 becomes one conductor, and the side of the sample S is electrically separated from the graphite crucible by the refractory sleeve 13 which is an insulator. Since it is insulated, the electrical resistance R in the layer thickness direction of the sample S can be measured. In this example, the electrical resistance between the hollow graphite rod 15 -graphite crucible 12 -solid graphite rod 16 (resistance other than sample S) is 0.02Ω in the case where sample S is not charged. Is negligible. The type of the electrical resistance measuring device is not particularly limited, but it is desirable to perform electrical resistance measurement under an alternating current (for example, 1 kHz). This is because when a direct current is used, when the sample melts into a liquid, it becomes an ionic conductor and mass transfer occurs, so that accurate numerical values cannot be read. Further, the refractory sleeve 13 is preferably selected from a material that does not react with the sample as well as does not soften and melt even at a temperature of at least 1500 ° C., preferably 1600 ° C.
[0015]
In order to obtain the electrical conductivity κ of the sample from the electrical resistance value R of the sample S measured as described above, the layer thickness h of the sample S must be obtained, and therefore a sample layer thickness measuring device 45 is provided. For this purpose, it is convenient to use the position of the solid graphite rod 16. Specifically, the lower end of the solid graphite rod 16 is brought into contact with the upper surface of the sample S, while a height gauge capable of measuring the upper surface position of the sample is provided at the upper end of the solid graphite rod 16 from the inner bottom surface of the graphite crucible 12. The distance to the lower end of 16 can be measured as the sample layer thickness h. The sample height measuring device 45 configured as described above uses a known operating transformer to detect a change in the position of the upper surface of the sample S, and the lower end of the solid graphite rod 16 is placed on the lower end of the solid graphite rod 16 without the sample S being loaded. The height of the crucible 12 is brought into contact with the inner bottom surface, the height at that time is set to 0, and the loaded sample layer thickness h may be determined based on this. The sample cross-sectional area can be calculated from the inner diameter of the refractory sleeve 13.
[0016]
Measurements such as the electrical resistance of ore samples at high temperatures must be recorded along with the sample temperature. Therefore, the sample temperature measuring device 47 must be provided as a means for measuring the temperature of the sample S in the high temperature property testing device for the electric furnace raw material for producing iron alloy of the present invention. The means can be, for example, a thermocouple inserted into the sample through the graphite crucible 12 and the refractory sleeve 13, but the solid graphite rod 16 has a pore 48 extending from the upper end to the vicinity of the lower end. It is convenient to insert a thermocouple into the bottom of 48 and measure the temperature of the bottom of the pore 48 measured thereby as the temperature of the sample S.
[0017]
Further, in the high temperature property testing apparatus for electric furnace raw materials for producing alloy iron of the present invention, it is necessary that the temperature of the sample exceeds 1000 ° C. and reaches at least 1500 ° C. This is because the inventor previously proposed an ore evaluation method, i.e., in the range of 1300 to 1500 ° C., the raw ore having an apparent electrical conductivity exceeding the apparent electrical conductivity of the carbon-based reducing agent is installed in the electric furnace. This is because a heating temperature of at least 1500 ° C. is required when adopting a method for determining an appropriate ore. In order to perform a high-temperature property evaluation test of raw ore quickly and reliably, it is preferable that the heating capacity of the apparatus of the present invention exceeds at least 1600 ° C.
[0018]
In this temperature range, the raw ore expands with increasing temperature in the solid phase and contracts with softening and melting. Therefore, the sample S must be reduced, for example, at a constant pressure during the measurement period so that the shrinkage due to the softening / melting can be compensated. For this purpose, an appropriate pressure is applied to the sample S through the solid graphite rod 16. Specifically, for example, a pressurizing device 61 capable of loading an appropriate weight or the like is provided in the vicinity of the upper end of the solid graphite rod 16 so that the adjusted pressure can be applied to the sample S.
[0019]
Further, in order to adjust the atmosphere in each process of heating, melting, and reduction of the sample S, an atmospheric gas is introduced from the gas introduction pipe 65 through the hollow graphite rod 15 into the alumina tube 14 through the gas introduction part 69. After the sample storage chamber is filled with the atmospheric gas, it is discharged from the gas discharge pipe 68 to the outside.
[0020]
In addition, when the atmospheric gas is blown into the sample S, as shown in FIG. 3, a large number of atmospheric gas inlets 66 can be provided at the lower end of the graphite crucible 12, and the hollow graphite rod 15 can be connected thereto. In this case, a slight gap 67 is required between the refractory sleeve 13 and the hollow graphite rod 16. As the atmospheric gas, an inert gas such as N 2 gas can be used, and any CO, CO 2 , H 2 mixed gas can be used. By having such a structure, the electrical conductivity of the ore can be measured while reproducing the indirect reduction reaction of the Mn-containing ore in the electric furnace.
[0021]
The apparatus for measuring high-temperature properties of an electric furnace raw material for producing iron alloy of the present invention is provided with a heating device 21 such as a SiC heating element in order to heat the temperature in the sample storage chamber 11 to at least 1500 ° C. . Further, the sample storage chamber 11 and the heating device 21 are surrounded by a heat insulating structure 31. The heat insulating structure 31 covers the whole with the iron skin 32 and reinforces the whole, and the heating device 21, the hollow graphite rod 15, and eventually the heat insulating structure 31 wound inside the iron skin and the inside thereof. The sample storage chamber 11 is preferably fixed.
[0022]
With the above apparatus, the temperature, electric resistance (R), and sample layer thickness (h) can be measured while heating the sample S. Furthermore, based on these measurement results, A is the sample cross-sectional area, and the electrical conductivity κ is
κ = h / (A ・ R)
It can ask for. Note that the electrical resistance (R) is not an absolute electrical resistance value of the ore, but an apparent electrical resistance value under conditions that take into account the electric furnace operating conditions, etc. Therefore, the electrical conductivity κ is also apparent. Electrical conductivity.
[0023]
The electric furnace charging ore can be evaluated based on the measured temperature and electric conductivity κ. The method has already been proposed by the present inventor in Japanese Patent Application No. 11-350817, but between 1300 and 1500 ° C., a raw material ore having an electric conductivity exceeding the electric conductivity of the carbon-based reducing agent is used. It is determined that the electric furnace is properly charged. In order to make this determination, a temperature-apparent electric conductivity relationship curve is drawn as shown in FIG. 4, and this is compared with a coke simple electric conductivity curve.
[0024]
Therefore, in the device of the present invention, for example, each measurement result is obtained from the electrical resistance measurement device 41, the sample temperature measurement device 47, and the sample layer thickness measurement device 45, and based on these, the electrical conductivity is calculated, and the coke plain It is also possible to provide an electrical conductivity computing device 51 that compares the electrical conductivity.
[0025]
Conditions for measuring the properties of ore by the apparatus of the present invention can be arbitrarily selected according to the operating conditions of the electric furnace, but typical examples are as follows.
Sample ore grain size: 3-5mm
Sample ore layer thickness: 50mm
Sample cross section: 6.15cm 2
Load on sample ore: 20kPa
Electrical resistance measurement frequency: 1kHz
[0026]
In addition, when adjusting the sample ore, it is preferable to use a material ore or the like to be evaluated and a mixture of coke having a particle size of 3 to 5 mm in a mass ratio of 10% and approximate the state in the electric furnace. The rate of temperature rise should be 10 ° C / min up to 1000 ° C and 3 ° C / min above it. Further, during the measurement, an inert gas is preferably allowed to flow to prevent oxidation of the graphite material in the sample storage chamber 11. These measurement conditions are also applied to the case of coke as a comparison target.
[0027]
FIG. 4 shows the results of measuring the high-temperature properties of various raw ores (L, M, N) and coke using the apparatus according to the present invention, and the relationship between the apparent electrical conductivity and temperature of the various raw ores and coke. It is. As is clear from this result, the ore L has a characteristic that the apparent electric conductivity is higher in the reduction temperature range of 1300 to 1500 ° C. than the ore M or N. In other words, the ore L is inferior in electrical conductivity compared to the ores M or N. For this reason, when a large amount of ore L was blended in actual operation, the electrode floated, and the phenomenon that it was difficult to apply power load appeared, and various basic units and Mn yield deteriorated. In contrast, when a large amount of ore M or N was blended, the electric conductivity of the raw material contained in the furnace was in the proper range, and good operation could be maintained.
[0028]
As described above, the result of evaluating the raw ore using the apparatus of the present invention shows a good agreement with the operation results of the electric furnace, and therefore the apparatus of the present invention accurately simulates the state in the electric furnace. I understand.
[0029]
With the test apparatus of the present invention, it has become possible to accurately evaluate the electrical conductivity of raw material ores that influence the operation of an electric furnace under the conditions of simulating the condition in an electric furnace for producing manganese-based alloy iron. As a result, it becomes possible to appropriately determine the composition of raw material ore, which contributes to the reduction of operating costs such as stable operation of the electric furnace, improvement of Mn yield, and reduction of power consumption rate.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the overall configuration of a high-temperature property testing apparatus for an electric furnace raw material for producing iron alloy according to the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is an enlarged view of a sample charging container of a high-temperature property testing apparatus for an electric furnace raw material for producing alloy iron according to the present invention.
FIG. 4 is a result of measuring the high-temperature properties of various raw ores and coke using the apparatus according to the present invention, and is a diagram showing the relationship between the apparent electrical conductivity and the temperature of various raw ores.
[Explanation of symbols]
11: Sample storage chamber
12: Graphite crucible
13: Refractory sleeve
14: Alumina tube
15: Hollow graphite rod
16: Solid graphite rod
17: Sample charging container
18, 19: Electrical terminal
21: Heating device
31: Thermal insulation structure
40: High temperature property measuring device
41: Electrical resistance measuring device
45: Sample layer thickness measuring device
47: Sample temperature measuring device
51: Electric conductivity calculator
61: Pressure device
65: Atmospheric gas introduction pipe
66: Atmospheric gas inlet
67: Clearance
68: Gas exhaust pipe
69: Gas introduction part
S: Sample

Claims (6)

合金鉄製造用の電気炉原料から調製された試料を収容する試料収容室と、
前記試料を少なくとも1500℃まで上昇させる加熱装置と、
前記加熱装置により加熱される試料を加圧しながら該試料の電気抵抗、層厚ならびに温度を測定する高温性状測定装置と、を備えることを特徴とする合金鉄製造用電気炉原料の高温性状試験装置。A sample storage chamber for storing a sample prepared from an electric furnace raw material for producing iron alloy;
A heating device for raising the sample to at least 1500 ° C .;
A high-temperature property measuring device for measuring the electrical resistance, layer thickness and temperature of the sample while pressurizing the sample heated by the heating device, . 試料収容室は、黒鉛るつぼと該黒鉛るつぼ内に嵌挿された耐火物スリーブとからなる試料装入容器と該試料装入容器を取り囲むアルミナチューブからなり、
前記アルミナチューブには底部から中空黒鉛棒、上部から中実黒鉛棒が差し込まれており、
前記中空黒鉛棒はその上端を前記黒鉛るつぼの底部に接して前記黒鉛るつぼを支持し、前記中実黒鉛棒はその下端を前記耐火物スリーブを通して試料上面に接して試料を加圧し、
かつ、前記中空黒鉛棒と前記中実黒鉛棒には電気抵抗測定装置が接続されていることを特徴とする請求項１に記載の合金鉄製造用電気炉原料の高温性状試験装置。The sample storage chamber is composed of a sample charging container composed of a graphite crucible and a refractory sleeve fitted in the graphite crucible, and an alumina tube surrounding the sample charging container.
A hollow graphite rod is inserted into the alumina tube from the bottom, and a solid graphite rod is inserted from the top.
The hollow graphite rod supports the graphite crucible with its upper end in contact with the bottom of the graphite crucible, and the solid graphite rod presses the sample with its lower end in contact with the upper surface of the sample through the refractory sleeve,
The high-temperature property testing apparatus for an electric furnace raw material for producing iron alloy according to claim 1, wherein an electrical resistance measuring device is connected to the hollow graphite rod and the solid graphite rod. 前記中実黒鉛棒には、該中実黒鉛棒の下端部から前記黒鉛るつぼの内底面に至る距離を計測する試料層厚測定装置が設けられていることを特徴とする請求項１又は２に記載の合金鉄製造用電気炉原料の高温性状試験装置。The solid graphite rod is provided with a sample layer thickness measuring device for measuring a distance from a lower end portion of the solid graphite rod to an inner bottom surface of the graphite crucible. A high-temperature property testing apparatus for an electric furnace raw material for producing the described alloy iron. 前記中実黒鉛棒には、上端から下端近傍に至る細孔が穿たれており、該細孔には熱電対が挿入されていることを特徴とする請求項１、２又は３に記載の合金鉄製造用電気炉原料の高温性状試験装置。The alloy according to claim 1, 2, or 3, wherein the solid graphite rod has pores extending from the upper end to the vicinity of the lower end, and a thermocouple is inserted into the pores. High-temperature property testing equipment for electric furnace raw materials for iron production. 前記中実黒鉛棒には、試料加圧調整手段が設けられていることを特徴とする請求項１〜４のいずれかに記載の合金鉄製造用電気炉原料の高温性状試験装置。The high-temperature property testing device for an electric furnace raw material for producing an iron alloy according to any one of claims 1 to 4, wherein the solid graphite rod is provided with a sample pressure adjusting means. 中空黒鉛棒には、外部から雰囲気ガスを受け入れるガス供給管と、該雰囲気ガスをアルミナチューブ内に導入するガス導入部が設けられていることを特徴とする請求項１〜５のいずれかに記載の合金鉄製造用電気炉原料の高温性状試験装置。The hollow graphite rod is provided with a gas supply pipe for receiving an atmospheric gas from the outside, and a gas introduction part for introducing the atmospheric gas into the alumina tube. For testing high temperature properties of raw materials for electric furnaces for the production of iron alloys.
JP2000240250A 2000-08-08 2000-08-08 High-temperature property testing equipment for electric furnace raw materials for alloy iron production Expired - Fee Related JP3646125B2 (en)

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JP2000240250A JP3646125B2 (en) 2000-08-08 2000-08-08 High-temperature property testing equipment for electric furnace raw materials for alloy iron production
AU57759/01A AU763233B2 (en) 2000-08-08 2001-08-01 Apparatus for testing the high temperature properties of a raw material to/be reformed in an electric furnace and a manganese-containing sintered ore to be reformed in an electric furnace and a method of producing the same
FR0110432A FR2812944B1 (en) 2000-08-08 2001-08-03 APPARATUS FOR TESTING HIGH TEMPERATURE PROPERTIES OF RAW MATERIAL TO BE PROCESSED IN AN ELECTRIC OVEN, SINTERED ORE CONTAINING MANGANESE AND METHOD FOR PRODUCING SUCH ORE
NO20013841A NO20013841L (en) 2000-08-08 2001-08-07 Apparatus for testing the high temperature properties of a raw material to be reformed in an electric furnace, and a single-contained sintered ore for reforming in an electric furnace and a method of making it
ZA200106475A ZA200106475B (en) 2000-08-08 2001-08-07 Apparatus for testing the high temperature properties of a raw material to/be reformed in an electric furnace and a manganese-containing sintered ore to be reformed in an electric furnace and a method of producing the same.
OA1200100211A OA11832A (en) 2000-08-08 2001-08-08 Apparatus for testing the high temperature properties of a raw material to be reformed in an electric furnace and a manganese-containing sintered ore to be reformed in an electric furnace and a method of producing the same.

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CN109706333A (en) * 2018-12-29 2019-05-03 中冶南方工程技术有限公司 A kind of manganeisen smelting device and technique
CN111380897A (en) * 2020-03-23 2020-07-07 本钢板材股份有限公司 Iron ore high temperature performance survey device

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