JP2000054034A - Operation of reduction furnace in production of reduced iron pellet - Google Patents
Operation of reduction furnace in production of reduced iron pelletInfo
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- JP2000054034A JP2000054034A JP21907398A JP21907398A JP2000054034A JP 2000054034 A JP2000054034 A JP 2000054034A JP 21907398 A JP21907398 A JP 21907398A JP 21907398 A JP21907398 A JP 21907398A JP 2000054034 A JP2000054034 A JP 2000054034A
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- Japan
- Prior art keywords
- reaction
- reduced iron
- time
- pellets
- pellet
- Prior art date
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- Manufacture And Refinement Of Metals (AREA)
- Manufacture Of Iron (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、還元鉄の製造方法
に関し、特に酸化鉄粉と炭素源を混合したペレットを回
転炉床式焼成還元炉（以下、回転炉床と称す）にて還元
する方法に関し、更に詳しくは、回転炉床にて製造され
た還元ペレットを経済的に製鉄用溶鉱炉で使用するため
の還元鉄ペレットの製造技術に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing reduced iron, and more particularly to a method in which pellets obtained by mixing iron oxide powder and a carbon source are reduced in a rotary hearth type firing reduction furnace (hereinafter referred to as a rotary hearth). More specifically, the present invention relates to a technique for producing reduced iron pellets for economically using reduced pellets produced in a rotary hearth in a blast furnace for ironmaking.
【０００２】[0002]
【従来の技術】還元鉄の製造プロセスとしては、水素ガ
スによるペレットの直接還元法、流動層によるガス還元
法等があるが、安価な石炭エネルギーをベースとする回
転炉床法、キルン法、その他を用いる還元鉄ペレットの
製造方法は、還元鉄の安価な製造方法として有効な技術
である。このうち、例えば特開平６−２３８２０７号公
報に示される、回転炉床法での還元鉄ペレットの製造方
法は、生産性、製品歩留まりが高い等の特徴を有し、特
に有効な技術である。回転炉床法は、その特徴を生か
し、鉄鉱石と石炭を用いた直接還元鉄の製造や、特殊鋼
の電気炉ダストの還元に用いられ、製品の還元ペレット
は主として電気炉用の鉄原料として用いられている。2. Description of the Related Art As a process for producing reduced iron, there are a direct reduction method of pellets with hydrogen gas, a gas reduction method with a fluidized bed, and the like, but a rotary hearth method, a kiln method, and the like based on inexpensive coal energy. The method for producing reduced iron pellets using the method is an effective technique as an inexpensive method for producing reduced iron. Among them, the method for producing reduced iron pellets by the rotary hearth method described in, for example, JP-A-6-238207 has features such as high productivity and high product yield, and is a particularly effective technique. The rotary hearth method takes advantage of its features, and is used for the production of direct reduced iron using iron ore and coal and for the reduction of electric furnace dust of special steel, and the reduced pellets of the product are mainly used as iron raw materials for electric furnaces. Used.
【０００３】[0003]
【発明が解決しようとする課題】従来技術では、還元鉄
ペレットの製造においては還元率、金属化率の向上目的
が主体であり、還元鉄ペレットの強度を高める技術はな
かった。従って、回転炉床法によって製造された還元鉄
ペレットは、強度が弱いため電気炉、転炉等での使用に
止まっていた。しかしながら、当該ペレットは石炭等の
炭素源からの硫黄が還元鉄中に固定されるため、硫黄の
含有率が０．１から０．３％以上と高く、転炉等の脱硫
能力の小さい製鋼炉では使用量が限られる、炉外での脱
硫費用がかかる等の問題が生じていた。従って、当該還
元鉄ペレットを安価かつ大量に使用するためには、脱硫
能力の大きい溶鉱炉で使用することが求められていた。In the prior art, in the production of reduced iron pellets, the main purpose is to improve the reduction ratio and the metallization ratio, and there is no technology for increasing the strength of the reduced iron pellets. Therefore, reduced iron pellets produced by the rotary hearth method have been used only in electric furnaces, converters, and the like because of their low strength. However, since the pellets contain sulfur from a carbon source such as coal in the reduced iron, the sulfur content is as high as 0.1 to 0.3% or more, and the steelmaking furnace such as a converter has a low desulfurization ability. However, there have been problems such as the limited amount of use and the cost of desulfurization outside the furnace. Therefore, in order to use the reduced iron pellets inexpensively and in large quantities, it has been required to use them in a blast furnace having a large desulfurization ability.
【０００４】一方、溶鉱炉においては、炉内での装入物
の崩壊粉化を避けるために、鉄鉱石、焼結鉱、焼成ペレ
ット、コークス等の強度の高い塊状物を装入原料として
使用している。一般的に溶鉱炉の装入原料は粒径５ｍｍ
以上、圧潰強度５０ｋｇｆ／ｃｍ2 （４．９×１０6 Ｎ
／ｍ2 ）以上のものである。しかしながら、従来の回転
炉床法での操業方法で製造された還元鉄ペレットの強度
は低く、２０から３０ｋｇｆ／ｃｍ2 程度の圧潰強度し
かなかった。その結果、この低強度の還元鉄ペレットを
溶鉱炉で使用すると、溶鉱炉内で容易に圧潰粉化してし
まい、溶鉱炉ダストとして排出され、鉄原料としての歩
留まりが悪いばかりか、発生した粉により溶鉱炉内の通
気が悪化し、操業が困難になるといった問題があった。
従って、従来法の回転炉床法で製造された還元鉄ペレッ
トを溶鉱炉で直接使用することはできなかった。On the other hand, in a blast furnace, high-strength lump materials such as iron ore, sintered ore, calcined pellets, coke and the like are used as a charging material in order to avoid collapse and powdering of the charged material in the furnace. ing. Generally, the charging material of the blast furnace has a particle size of 5 mm.
As described above, the crushing strength is 50 kgf / cm 2 (4.9 × 10 6 N
/ M 2 ). However, the reduced iron pellets produced by the conventional rotary hearth operation method have low strength, and have a crushing strength of only about 20 to 30 kgf / cm 2 . As a result, when this low-strength reduced iron pellet is used in a blast furnace, it is easily crushed into powder in the blast furnace, is discharged as blast furnace dust, not only has a low yield as iron raw material, but also due to the generated powder, There was a problem that ventilation became worse and operation became difficult.
Therefore, the reduced iron pellets produced by the conventional rotary hearth method cannot be directly used in a blast furnace.
【０００５】この問題を回避するためには、製造した還
元鉄ペレットを、さらに、ホットブリケット装置で圧縮
成型した高強度ブリケットを溶鉱炉で使用する方法があ
るが、そのために余分な費用がかかり、経済的ではなか
った。従って、回転炉床法で製造された還元鉄ペレット
を溶鉱炉で直接使用できるような高強度の還元鉄ペレッ
トの製造方法が望まれていた。これに対し、本発明者ら
は同時期に出願した発明により、還元鉄ペレットの残留
炭素を適正範囲に制御すること、あるいは配合原料にお
ける鉄分重量割合及び炭素配合比率を適正範囲に調整す
ることにより、高炉での使用に耐え得る高強度の還元鉄
ペレットの製造方法を発見した。[0005] In order to avoid this problem, there is a method in which the produced reduced iron pellets are further used in a blast furnace with high-strength briquettes obtained by compression molding using a hot briquetting apparatus. It was not a target. Accordingly, there has been a demand for a method for producing high-strength reduced iron pellets that can directly use reduced iron pellets produced by the rotary hearth method in a blast furnace. On the other hand, the present inventors, by the invention filed at the same time, control the residual carbon of the reduced iron pellets to an appropriate range, or adjust the iron weight ratio and the carbon mixing ratio in the compounding raw materials to the appropriate range. Discovered a method for producing high-strength reduced iron pellets that can withstand use in a blast furnace.
【０００６】このような条件にて、還元反応を十分に行
うことにより所期の目的である高強度還元鉄ペレットの
製造が達成される。しかしながら、還元炉において還元
反応を最も経済的に行うための必要最小限の還元温度及
び時間の設定方法について定量的に言及された技術はこ
れまでになく、回転炉床法の生産効率、経済性を最も向
上させ得る還元鉄ペレット製造のための還元炉操業技術
が望まれていた。[0006] Under such conditions, by sufficiently performing the reduction reaction, the intended production of high-strength reduced iron pellets is achieved. However, there has never been a technology that quantitatively mentions the method of setting the minimum necessary reduction temperature and time for the most economical reduction reaction in a reduction furnace. There has been a demand for a reduction furnace operation technique for producing reduced iron pellets, which can most effectively improve the reduction of iron pellets.
【０００７】さらには、還元鉄ペレットの製造原料とし
て、鉄鋼製造工程で発生する鉄分及び炭素分含有ダスト
を用いることができれば、資源の再利用による廃棄物の
低減が図られ、環境面からも切に望まれるものである。
このような、ダスト類は、亜鉛分を含むことが多く、そ
のままの亜鉛含有量にて高炉で使用した場合、高炉炉壁
部にて亜鉛系の付着物が成長し、高炉内のガス流れや原
料降下に異常を来すといった問題があった。従って、こ
のような鉄鋼製造工程で発生する鉄分及び炭素分含有ダ
ストを原料として製造した還元鉄ペレットの高炉での直
接使用においては、強度面に加え、亜鉛分の除去につい
ても考慮しなければならない。[0007] Further, if dust containing iron and carbon generated in the steelmaking process can be used as a raw material for producing reduced iron pellets, waste can be reduced by reusing resources and the environment can be reduced. It is what is desired.
Such dusts often contain zinc, and when used in a blast furnace with the same zinc content, zinc-based deposits grow on the wall of the blast furnace, causing gas flow and gas flow in the blast furnace. There was a problem that abnormalities occurred in the material drop. Therefore, in the direct use in a blast furnace of reduced iron pellets produced using such dusts containing iron and carbon generated in the steel production process, in addition to strength, it is necessary to consider the removal of zinc. .
【０００８】従って、製鋼製造工程で発生するダスト、
場合により亜鉛分を含むダストを原料として回転炉床法
で製造された還元鉄ペレットを、溶鉱炉で直接使用でき
るような高強度低亜鉛の還元鉄ペレットを製造するにあ
たり、回転炉床法の生産効率、経済性を最も向上させ得
る還元鉄ペレット製造のための還元炉操業技術が望まれ
ていた。Therefore, dust generated in the steel making process,
In some cases, the production efficiency of the rotary hearth method is used to produce reduced-strength iron pellets of high strength and low zinc that can be directly used in blast furnaces using reduced iron pellets produced by the rotary hearth method using dust containing zinc as a raw material. There has been a demand for a reduction furnace operating technique for producing reduced iron pellets that can maximize the economic efficiency.
【０００９】[0009]
【課題を解決するための手段】本発明は、 （１）回転炉床式焼成還元炉内にて、炭材及び酸化鉄の
混合原料を造粒したペレットを還元処理して還元鉄ペレ
ットを製造するにあたり、還元炉内の反応温度及び時間
を、下記で示されるような還元反応におけるペレット温
度の時間積分形式で計算される反応指標と消費炭素量と
の関係に基づいて適正に調整することを特徴とする還元
鉄ペレット製造における還元炉操業方法。 反応指標＝∫ｅｘｐ（−Ｔｒ／Ｔｔ）ｄｔ （ただし、Ｔｒは定数、Ｔｔは時間ｔでのペレット温
度）Means for Solving the Problems The present invention provides: (1) Reduced pellets obtained by granulating a mixed material of carbonaceous material and iron oxide in a rotary hearth type sintering reduction furnace to produce reduced iron pellets. In doing so, it is necessary to appropriately adjust the reaction temperature and time in the reduction furnace based on the relationship between the reaction index calculated in the form of time integration of the pellet temperature in the reduction reaction as shown below and the carbon consumption. Characteristic method of operating a reduction furnace in the production of reduced iron pellets. Reaction index = ∫exp (−Tr / Tt) dt (where Tr is a constant and Tt is the pellet temperature at time t)
【００１０】（２）反応指標中の定数Ｔｒを１３２３Ｋ
とし、時間の単位として分を用いて計算した反応指標
が、２．８以上８．０以下になるような反応温度および
／または反応時間とすることを特徴とする前記（１）に
記載の還元鉄ペレット製造における還元炉操業方法。 （３）炭材及び酸化鉄の混合原料として、鉄鋼製造工程
で発生する鉄分及び炭素分含有ダストを用いることを特
徴とする前記（１）または（２）に記載の還元鉄ペレッ
ト製造における還元炉操業方法。(2) The constant Tr in the reaction index is set to 1323K
Wherein the reaction index calculated using minutes as a unit of time is a reaction temperature and / or a reaction time such that the reaction index is 2.8 or more and 8.0 or less. Operating method of reduction furnace in iron pellet production. (3) The reduction furnace in the production of reduced iron pellets according to (1) or (2), wherein dust containing iron and carbon generated in a steel manufacturing process is used as a mixed raw material of carbon material and iron oxide. Operation method.
【００１１】（４）炭材及び酸化鉄の混合原料として、
鉄鋼製造工程で発生する鉄分及び炭素分含有ダストを用
いると共に、ダスト中に亜鉛分が含まれる場合におい
て、反応指標中のＴｒを１３２３Ｋとし、時間の単位と
して分を用いて計算した反応指標が、３．２以上８．０
以下になるような反応温度および／または反応時間とす
ることを特徴とする前記（１）に記載の還元鉄ペレット
製造における還元炉操業方法である。すなわち、本発明
においては、回転炉床法で製造した還元鉄ペレットを溶
鉱炉にて直接使用する目的にかなった高強度低亜鉛の還
元鉄ペレットの効率的かつ経済的な製造技術を提供する
ものである。(4) As a mixed raw material of carbon material and iron oxide,
Using iron and carbon-containing dust generated in the iron and steel manufacturing process, when zinc is contained in the dust, Tr in the reaction index is set to 1323K, the reaction index calculated using minutes as a unit of time, 3.2 or more and 8.0
The method for operating a reduction furnace in the production of reduced iron pellets according to the above (1), wherein the reaction temperature and / or the reaction time are as follows. That is, the present invention provides an efficient and economical technique for producing high-strength, low-zinc reduced iron pellets for the purpose of directly using reduced iron pellets produced by the rotary hearth method in a blast furnace. is there.
【００１２】[0012]
【発明の実施の形態】回転炉床内においては、石炭、コ
ークス、その他の炭素源及び粉鉱石、その他の酸化鉄等
を主体とした混合原料に、場合によりベントナイト等の
バインダーを添加したものを造粒機にて造粒したペレッ
ト（以下、生ペレットと称す）を、回転炉床内にて加熱
して、生ペレット内にて、 Ｃ＋Ｆｅt Ｏ＝ＣＯ＋ｔＦｅ ＣＯ＋Ｆｅt Ｏ＝ＣＯ2 ＋ｔＦｅ の反応により、金属鉄を生じる。１０００℃程度からこ
の反応が始まるが、１２００℃以上では、反応が特に活
発になり、回転炉床の生産性が向上するため、一般的に
は、１２００℃以上の反応温度で操業を行っている。BEST MODE FOR CARRYING OUT THE INVENTION In a rotary hearth, a mixed raw material mainly composed of coal, coke, other carbon sources, fine ore, and other iron oxides, and optionally a binder such as bentonite is added. granulated pellets (hereinafter, green pellets hereinafter) at granulator, and heated in a rotary furnace bed at the green pellets, by reaction C + Fe t O = CO + tFe CO + Fe t O = CO 2 + tFe Produces metallic iron. This reaction starts at about 1000 ° C., but at 1200 ° C. or higher, the reaction becomes particularly active and the productivity of the rotary hearth improves, so that the operation is generally performed at a reaction temperature of 1200 ° C. or higher. .
【００１３】本発明者らは、図１に示す回転炉床の実験
炉において、種々の実験を行い、溶鉱炉での使用に耐え
うる高強度の還元ペレットの製造方法を研究した結果、
還元反応にて消費される炭素量を、ペレットの温度を時
間積分して計算した反応指標にて制御することができ、
所期の目的にあった高強度の還元鉄ペレットを経済的に
製造できることを見出した。The present inventors conducted various experiments in a rotary hearth experimental furnace shown in FIG. 1 and studied a method of producing high-strength reduced pellets that can withstand use in a blast furnace.
The amount of carbon consumed in the reduction reaction can be controlled by a reaction index calculated by integrating the temperature of the pellet over time,
It has been found that high-strength reduced iron pellets meeting the intended purpose can be produced economically.
【００１４】図１において、１は発熱体であり、アルミ
ナ管２の炉床に置かれたアルミナボート３の上にペレッ
ト４を置いて上下方向から焼成する。アルミナ管の端部
は栓でふさがれており、栓の中央を貫通して窒素等の雰
囲気ガスを吹き込むガス管５が差し込まれている。６は
熱電対であり、レコーダー７を介して装置内の温度を予
定の温度に保っている。In FIG. 1, reference numeral 1 denotes a heating element, and pellets 4 are placed on an alumina boat 3 placed on a hearth of an alumina tube 2 and fired from above and below. The end of the alumina tube is plugged with a plug, and a gas tube 5 that penetrates through the center of the plug and blows an atmospheric gas such as nitrogen is inserted. Reference numeral 6 denotes a thermocouple, which keeps the temperature inside the apparatus at a predetermined temperature via a recorder 7.
【００１５】本発明者らは、まず実験炉内の設定温度に
対し、ペレットがどのような温度上昇パターンをとる
か、生ペレットに熱電対をセットして実測した。その結
果図２に示す通り、ペレットが設定温度に到達するまで
の温度上昇パターンとして、昇温開始から設定温度へ近
づくにつれて徐々に昇温速度が低下し、滑らかに設定温
度まで上昇すること、及びこの昇温速度が設定温度の違
いにより、差があることを見出した。すなわち、還元炉
内での生ペレットの還元反応を定量的に制御するために
は、生ペレット自体の温度上昇パターンを十分考慮する
必要があることが判った。つまり、還元炉の設定温度が
一定条件でも、ペレットが設定温度に到達するまでに所
定時間かかるため、反応時間の比例のみで還元反応量を
単純に推定することができないということである。The present inventors first measured the temperature rise pattern of the pellet with respect to the set temperature in the experimental furnace by setting a thermocouple on the raw pellet. As a result, as shown in FIG. 2, as a temperature rising pattern until the pellets reach the set temperature, the heating rate gradually decreases as the temperature approaches the set temperature from the start of heating, and rises smoothly to the set temperature. It has been found that there is a difference in the heating rate depending on the set temperature. That is, it was found that in order to quantitatively control the reduction reaction of the raw pellets in the reduction furnace, it is necessary to sufficiently consider the temperature rise pattern of the raw pellets themselves. In other words, even if the set temperature of the reduction furnace is constant, it takes a predetermined time for the pellets to reach the set temperature, so that the reduction reaction amount cannot be simply estimated only by the proportionality of the reaction time.
【００１６】これに対し、本発明者らは、種々の反応温
度及び反応時間において、炭材及び酸化鉄の混合原料を
造粒したペレットを還元処理した結果、還元炉の設定温
度の違いにかかわらず、下記の式に示されるようなペレ
ットの温度を時間積分計算して得られた反応指標と、還
元反応にて消費される炭素量との間に強い相関があるこ
とを見出した。 反応指標＝∫ｅｘｐ（−Ｔｒ／Ｔｔ）ｄｔ （ただし、Ｔｒは定数、Ｔｔは時間ｔでのペレット温
度） さらに詳しくは、本実験条件においては、反応指標の計
算における定数Ｔｒを１３２３Ｋを用いることにより、
図３に示すごとく、極めて精度よく、反応指標と還元に
よる消費炭素量の相関関係を得ることができることを見
出した。On the other hand, the present inventors have performed a reduction treatment on pellets obtained by granulating a mixed raw material of carbonaceous material and iron oxide at various reaction temperatures and reaction times, and as a result, despite the difference in the set temperature of the reduction furnace. Instead, it was found that there was a strong correlation between the reaction index obtained by time-integrating the temperature of the pellet as shown in the following formula and the amount of carbon consumed in the reduction reaction. Reaction index = ∫exp (−Tr / Tt) dt (where Tr is a constant, Tt is the pellet temperature at time t) In more detail, in this experimental condition, the constant Tr in the calculation of the reaction index should be 1323K. By
As shown in FIG. 3, it was found that the correlation between the reaction index and the amount of carbon consumed by the reduction can be obtained extremely accurately.
【００１７】また、図４に示すように、消費炭素量と還
元鉄ペレットの圧潰強度との関係より、消費炭素量が１
０％を越えると、還元鉄ペレットの圧潰強度が、溶鉱炉
装入に必要な５０ｋｇｆ／ｃｍ2 以上が得られることか
ら、図３において反応指標の計算値が２．８以上となる
ような反応温度及び／または反応時間を設定すること
で、消費炭素量が１０％以上となり、圧潰強度５０ｋｇ
ｆ／ｃｍ2 以上の高強度還元鉄ペレットの製造が可能で
あることを見出した。また、反応指標の計算値が８．０
以上では、炭素の消費量が殆ど変化せず、ほぼ飽和状態
となっていると考えてよいため、反応指標の上限の目安
は８．０とすることが妥当である。Further, as shown in FIG. 4, from the relationship between the amount of consumed carbon and the crushing strength of the reduced iron pellets, the amount of consumed carbon is 1 unit.
If the content exceeds 0%, the crushing strength of the reduced iron pellets is 50 kgf / cm 2 or more required for charging the blast furnace. Therefore, the reaction temperature at which the calculated value of the reaction index becomes 2.8 or more in FIG. 3 is obtained. By setting the reaction time and / or the reaction time, the carbon consumption becomes 10% or more, and the crushing strength is 50 kg.
It has been found that high strength reduced iron pellets of f / cm 2 or more can be produced. The calculated value of the response index is 8.0.
Above, it can be considered that the carbon consumption hardly changes and it is almost saturated, so it is appropriate to set the standard of the upper limit of the reaction index to 8.0.
【００１８】さらに、発明者らは、混合原料として鉄鋼
製造工程で発生する鉄分、炭素及び亜鉛分を含有するダ
ストを用いて、当該反応指標と還元鉄ペレットの脱亜鉛
率との関係を調査する実験を行った。この結果、図５に
示すとおり、反応指標の計算値が３．２に達するまで脱
亜鉛率が急激に上昇し、３．２以上で徐々に脱亜鉛率が
飽和に近づくことを見出した。従って、原料ダストから
の亜鉛の除去を効率的に行うためには、反応指標の計算
値が３．２以上となるような反応温度及び／または反応
時間を設定することが望ましいことを見出した。Further, the present inventors investigate the relationship between the reaction index and the dezincing rate of reduced iron pellets, using dust containing iron, carbon and zinc generated in the steelmaking process as a mixed raw material. An experiment was performed. As a result, as shown in FIG. 5, it was found that the dezincing rate sharply increased until the calculated value of the reaction index reached 3.2, and that the dezincing rate gradually approached saturation at 3.2 or more. Therefore, in order to efficiently remove zinc from the raw material dust, it has been found that it is desirable to set the reaction temperature and / or reaction time so that the calculated value of the reaction index becomes 3.2 or more.
【００１９】以上のような定数Ｔｒ及び反応指標の目標
値を設定することにより、回転炉床式焼成還元炉によ
り、かなり精度よく初期の目的である高強度低亜鉛の還
元鉄ペレットを効率的かつ経済的に製造することができ
るが、還元炉により炉内設定温度と実際のペレット温度
との関係に微妙な違いがあるため、実際にペレットの温
度を測定するなどにより、定数Ｔｒや反応指標の目標値
を調整して使用することも可能である。By setting the constant Tr and the target value of the reaction index as described above, the rotary hearth-type sintering reduction furnace efficiently and efficiently converts the high-strength, low-zinc reduced iron pellets, which is the initial object, to an initial object. Although it can be manufactured economically, there is a delicate difference in the relationship between the set temperature inside the furnace and the actual pellet temperature depending on the reduction furnace. It is also possible to adjust and use the target value.
【００２０】本発明の実験による還元鉄ペレットの反応
の進行状況を確認するために、実験を行った還元鉄ペレ
ットの組織分析を行ったところ、反応指標の目標値以上
の条件で反応を行った高強度の還元鉄ペレットでは、還
元反応が進み、金属鉄がペレット全体に分布しており、
金属鉄のネットワークにより強度が発現していることを
見出した。一方、反応指標の目標値に達しない条件で反
応を行った還元鉄ペレットは、還元鉄ペレット内での金
属鉄の存在比率が低く、ネットワークの形成が不十分で
あり、強度の発現がなされていなかった。In order to confirm the progress of the reaction of the reduced iron pellets in the experiment of the present invention, the microstructure of the reduced iron pellets that were subjected to the experiment was analyzed. In high-strength reduced iron pellets, the reduction reaction proceeds, and metallic iron is distributed throughout the pellets.
It was found that strength was developed by the metallic iron network. On the other hand, reduced iron pellets reacted under conditions that do not reach the target value of the reaction index have a low percentage of metallic iron in the reduced iron pellets, have insufficient network formation, and have developed strength. Did not.
【００２１】以上より、回転炉床法にて、炭材及び酸化
鉄の混合原料を造粒したペレットを還元処理して還元鉄
ペレットを製造するにあたり、還元炉内の反応温度及び
時間を、下記で示されるような還元反応におけるペレッ
ト温度の時間積分形式で計算される反応指標と消費炭素
量との関係に基づいて適正に調整することにより、圧潰
強度５０ｋｇｆ／ｃｍ2 以上の高強度還元鉄ペレットを
効率的かつ経済的に製造でき、これを溶鉱炉で直接使用
できることを、本発明者らは見出した。 反応指標＝∫ｅｘｐ（−Ｔｒ／Ｔｔ）ｄｔ （ただし、Ｔｒは定数、Ｔｔは時間ｔでのペレット温
度）As described above, when the pellets obtained by granulating the mixed material of the carbon material and the iron oxide by the rotary hearth method are reduced to produce reduced iron pellets, the reaction temperature and time in the reduction furnace are as follows. By properly adjusting the reaction index calculated in the form of a time integration of the pellet temperature in the reduction reaction as shown by the formula and the amount of carbon consumed, a high-strength reduced iron pellet having a crushing strength of 50 kgf / cm 2 or more is obtained. Have found that can be produced efficiently and economically and can be used directly in blast furnaces. Reaction index = ∫exp (−Tr / Tt) dt (where Tr is a constant and Tt is the pellet temperature at time t)
【００２２】[0022]
【実施例】本発明で得られた操業条件において、回転炉
床法にて操業条件を適正に行った結果、以下に示される
高強度の還元鉄ペレットを製造でき、溶鉱炉で使用する
ことができた。 EXAMPLES Under the operating conditions obtained in the present invention, the operating conditions were properly adjusted by the rotary hearth method. As a result, high-strength reduced iron pellets shown below can be manufactured and used in a blast furnace. Was.
【００２３】[0023]
【発明の効果】本発明の回転炉床法により、炭材及び酸
化鉄の混合原料を造粒したペレットを還元処理して還元
鉄ペレットを製造するにあたり、還元炉内の反応温度及
び時間を、還元反応におけるペレット温度の時間積分形
式で計算される反応指標と消費炭素量との関係に基づい
て適正に調整することにより、圧潰強度５０ｋｇｆ／ｃ
ｍ2 以上の高強度還元鉄ペレットが製造でき、これを溶
鉱炉で直接使用できることとなり、還元ペレットを溶鉱
炉にて直接使用するという目的にかなった高強度の還元
鉄ペレットの効率的かつ経済的な製造技術を提供可能と
なった。According to the rotary hearth method of the present invention, when reducing pellets obtained by granulating a mixed raw material of carbonaceous material and iron oxide to produce reduced iron pellets, the reaction temperature and time in the reduction furnace are determined as follows. By appropriately adjusting the crushing strength to 50 kgf / c based on the relationship between the reaction index calculated in the time integration form of the pellet temperature in the reduction reaction and the carbon consumption,
m 2 or more high-strength reduced iron pellets can be produced, which will be able to directly use in the blast furnace, efficient and economical production of reduced iron pellets strength suitable for the purpose of directly using reduced pellets at a blast furnace Technology can be provided.
【図１】本発明の実験に用いた電気炉焼成還元装置の概
略図、FIG. 1 is a schematic view of an electric furnace sintering reduction apparatus used in an experiment of the present invention,
【図２】本発明の実験結果による還元炉内での時間経過
によるペレット温度測定値を示す図、FIG. 2 is a diagram showing measured values of pellet temperature over time in a reduction furnace according to the experimental results of the present invention;
【図３】本発明の実験結果による反応指標と還元による
消費炭素量の関係を示した相関図、FIG. 3 is a correlation diagram showing the relationship between the reaction index based on the experimental results of the present invention and the amount of carbon consumed by reduction;
【図４】本発明の実験結果による消費炭素量と還元鉄ペ
レットの圧潰強度との関係を示した相関図、FIG. 4 is a correlation diagram showing the relationship between the amount of carbon consumed and the crushing strength of reduced iron pellets according to the experimental results of the present invention,
【図５】本発明の実験結果による反応指標と還元鉄ペレ
ットの脱亜鉛率との関係を示した相関図である。FIG. 5 is a correlation diagram showing the relationship between the reaction index and the dezincification rate of reduced iron pellets based on the experimental results of the present invention.
１ 発熱体 ２ アルミナ管 ３ アルミナボート ４ ペレット ５ 雰囲気ガス導入管 ６ 熱電対 ７ レコーダー DESCRIPTION OF SYMBOLS 1 Heating element 2 Alumina pipe 3 Alumina boat 4 Pellets 5 Atmospheric gas introduction pipe 6 Thermocouple 7 Recorder
Claims (4)
酸化鉄の混合原料を造粒したペレットを還元処理して還
元鉄ペレットを製造するにあたり、還元炉内の反応温度
及び時間を、下記で示されるような還元反応におけるペ
レット温度の時間積分形式で計算される反応指標と消費
炭素量との関係に基づいて適正に調整することを特徴と
する還元鉄ペレット製造における還元炉操業方法。 反応指標＝∫ｅｘｐ（−Ｔｒ／Ｔｔ）ｄｔ （ただし、Ｔｒは定数、Ｔｔは時間ｔでのペレット温
度）In a rotary hearth type sintering reduction furnace, a reaction temperature and a time in a reduction furnace for producing reduced iron pellets by subjecting pellets obtained by granulating a mixed material of a carbon material and iron oxide to reduction processing. The reduction furnace operation in the production of reduced iron pellets, characterized in that it is appropriately adjusted based on the relationship between the reaction index calculated in the form of time integration of the pellet temperature and the amount of carbon consumed in the reduction reaction as shown below. Method. Reaction index = ∫exp (−Tr / Tt) dt (where Tr is a constant and Tt is the pellet temperature at time t)
し、時間の単位として分を用いて計算した反応指標が、
２．８以上８．０以下になるような反応温度および／ま
たは反応時間とすることを特徴とする請求項１に記載の
還元鉄ペレット製造における還元炉操業方法。2. The reaction index calculated using a constant Tr of 1323 K in the reaction index and using minutes as a unit of time is as follows:
The method according to claim 1, wherein the reaction temperature and / or the reaction time is 2.8 or more and 8.0 or less.
製造工程で発生する鉄分及び炭素分含有ダストを用いる
ことを特徴とする請求項１または２に記載の還元鉄ペレ
ット製造における還元炉操業方法。3. The operation of a reduction furnace in the production of reduced iron pellets according to claim 1 or 2, wherein dust containing iron and carbon generated in a steel production process is used as a mixed raw material of carbonaceous material and iron oxide. Method.
製造工程で発生する鉄分及び炭素分含有ダストを用いる
と共に、ダスト中に亜鉛分が含まれる場合において、反
応指標中のＴｒを１３２３Ｋとし、時間の単位として分
を用いて計算した反応指標が、３．２以上８．０以下に
なるような反応温度および／または反応時間とすること
を特徴とする請求項１に記載の還元鉄ペレット製造にお
ける還元炉操業方法。4. As a mixed raw material of a carbon material and iron oxide, dust containing iron and carbon generated in a steel manufacturing process is used, and when zinc is contained in dust, Tr in a reaction index is set to 1323K. The reduced iron pellet according to claim 1, wherein the reaction index calculated using minutes as a unit of time is a reaction temperature and / or a reaction time such that the reaction index is 3.2 or more and 8.0 or less. Operating method of reduction furnace in manufacturing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21907398A JP2000054034A (en) | 1998-08-03 | 1998-08-03 | Operation of reduction furnace in production of reduced iron pellet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21907398A JP2000054034A (en) | 1998-08-03 | 1998-08-03 | Operation of reduction furnace in production of reduced iron pellet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000054034A true JP2000054034A (en) | 2000-02-22 |
Family
ID=16729847
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21907398A Pending JP2000054034A (en) | 1998-08-03 | 1998-08-03 | Operation of reduction furnace in production of reduced iron pellet |
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| Country | Link |
|---|---|
| JP (1) | JP2000054034A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6986801B2 (en) | 2001-09-14 | 2006-01-17 | Nippon Steel Corporation | Method of producing reduced iron compacts in rotary hearth-type reducing furnace, reduced iron compacts, and method of producing molten iron using them |
| US7037356B2 (en) | 2000-11-10 | 2006-05-02 | Nippon Steel Corporation | Method for operating rotary hearth type reducing furnace and rotary hearth type reducing furnace facilities |
| WO2016185801A1 (en) * | 2015-05-18 | 2016-11-24 | 物産フードサイエンス株式会社 | Method for producing modified xylopolysaccharides |
-
1998
- 1998-08-03 JP JP21907398A patent/JP2000054034A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7037356B2 (en) | 2000-11-10 | 2006-05-02 | Nippon Steel Corporation | Method for operating rotary hearth type reducing furnace and rotary hearth type reducing furnace facilities |
| US6986801B2 (en) | 2001-09-14 | 2006-01-17 | Nippon Steel Corporation | Method of producing reduced iron compacts in rotary hearth-type reducing furnace, reduced iron compacts, and method of producing molten iron using them |
| WO2016185801A1 (en) * | 2015-05-18 | 2016-11-24 | 物産フードサイエンス株式会社 | Method for producing modified xylopolysaccharides |
| JP2016216552A (en) * | 2015-05-18 | 2016-12-22 | 国立大学法人信州大学 | Manufacturing method of modified xylopolysaccharide |
| CN107614535A (en) * | 2015-05-18 | 2018-01-19 | 物产食品科技股份有限公司 | The manufacture method of modified polyxylan |
| US10858685B2 (en) | 2015-05-18 | 2020-12-08 | B Food Science Co., Ltd. | Method for producing modified xylopolysaccharide |
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