JP3531464B2 - Method for producing sintered ore with low SiO2 content - Google Patents
Method for producing sintered ore with low SiO2 contentInfo
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- JP3531464B2 JP3531464B2 JP07315998A JP7315998A JP3531464B2 JP 3531464 B2 JP3531464 B2 JP 3531464B2 JP 07315998 A JP07315998 A JP 07315998A JP 7315998 A JP7315998 A JP 7315998A JP 3531464 B2 JP3531464 B2 JP 3531464B2
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- raw material
- solid fuel
- sinter
- fuel powder
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Description
【０００１】[0001]
【発明が属する技術分野】本発明は、低ＳｉＯ２含有量
で且つ高被還元性の焼結鉱の製造方法に関するもので、
特に、微粉炭多量吹き込みを伴う高炉の低シリコン操業
に好適な焼結鉱の製造方法を提供するものである。TECHNICAL FIELD The present invention relates to a method for producing a sinter having a low SiO 2 content and a high reducibility,
In particular, the present invention provides a method for producing a sintered ore suitable for low silicon operation of a blast furnace accompanied by blowing a large amount of pulverized coal.
【０００２】[0002]
【従来の技術】従来一般に、高炉原料となる焼結鉱のＳ
ｉＯ2含有量は５．５〜６．０重量％程度に管理されて
きた。これは、焼結鉱のＳｉＯ2含有量を減らすと焼結
鉱の生産性や強度が著しく低下するためである。一方、
高炉操業におけるコークス比低減のためには高炉スラグ
比の低減が不可欠であり、従来、このような観点から焼
結鉱のＳｉＯ2含有量を低減させる努力がなされてき
た。2. Description of the Related Art Generally, S of sintered ore, which is a raw material for blast furnace,
The iO 2 content has been controlled to about 5.5 to 6.0% by weight. This is because if the SiO 2 content of the sinter is reduced, the productivity and strength of the sinter will significantly decrease. on the other hand,
In order to reduce the coke ratio in the blast furnace operation, it is essential to reduce the blast furnace slag ratio, and efforts have been conventionally made to reduce the SiO 2 content of the sinter from this viewpoint.
【０００３】さらに、近年では、高炉−転炉法の製鋼工
程から排出されるスラグのうち、脱燐スラグ等の溶銑予
備処理スラグの埋め立て処理が困難となりつつあるた
め、その発生量を抑制することが急務となっている。そ
こで、転炉における脱燐効率を向上させるために、溶銑
製造工程である高炉操業において溶銑中Ｓｉ濃度が０．
１重量％以下であるような、いわゆる低シリコン操業の
実施も検討されつつあり、このような低シリコン操業を
行うためには、高炉原料の約８０％を占める成品焼結鉱
のＳｉＯ2含有量を低減させることが不可欠である。Further, in recent years, of the slag discharged from the steelmaking process of the blast furnace-converter method, it is becoming difficult to bury the hot metal pretreatment slag such as dephosphorization slag, so that the amount of slag generated is suppressed. Is an urgent task. Therefore, in order to improve the dephosphorization efficiency in the converter, the Si concentration in the hot metal is 0.
The implementation of so-called low-silicon operations, such as 1% by weight or less, is also under consideration. To perform such low-silicon operations, the SiO 2 content of the product sinter that accounts for about 80% of the blast furnace raw material It is essential to reduce
【０００４】また、最近の高炉操業では、コスト削減の
ために補助燃料として安価な一般炭を羽口から吹き込む
微粉炭吹込み操業が広く実施されているが、この微粉炭
の吹き込み量は年々増加する傾向にあり、一般に銑鉄１
ｔ当たり微粉炭１５０ｋｇ以上の吹き込みが要求される
ようになりつつある。この背景には、コークス炉の負荷
を軽減して炉の寿命延長を図るとともに、省資源の面か
ら原料炭の使用比率を削減し、一般炭の使用比率を上げ
ることが求められている事情がある。Further, in recent blast furnace operation, pulverized coal blowing operation in which inexpensive steam coal is blown as an auxiliary fuel from tuyere is widely practiced for cost reduction, but the amount of pulverized coal injected is increasing year by year. Pig iron 1 in general
It is becoming necessary to blow 150 kg or more of pulverized coal per t. Behind this is the situation where it is required to reduce the load on the coke oven to extend the life of the coke oven, reduce the usage ratio of coking coal and increase the usage ratio of steam coal from the viewpoint of resource saving. is there.
【０００５】ところで、高炉での微粉炭吹き込み量を増
加させると炉内ガス発生量が多くなるため、微粉炭多量
吹込みを実施するためには高炉内部に形成される軟化溶
融帯（この軟化溶融帯は炉内通気性を阻害する）の厚み
を減じ、炉内通気性を確保することが不可欠である。そ
して、この軟化溶融帯の厚みを減ずるためには、焼結鉱
のＳｉＯ2含有量を下げるとともに、焼結鉱の被還元性
を向上させる必要がある。When the amount of pulverized coal blown into the blast furnace is increased, the amount of gas generated in the furnace is increased. Therefore, in order to carry out a large amount of pulverized coal blow, a softening and melting zone (this softening and melting zone) formed inside the blast furnace is used. It is indispensable to reduce the thickness of the belt (which obstructs the air permeability in the furnace) and ensure the air permeability in the furnace. In order to reduce the thickness of this softening / melting zone, it is necessary to reduce the SiO 2 content of the sinter and improve the reducibility of the sinter.
【０００６】したがって、微粉炭多量吹込みを伴う高炉
の低シリコン操業を実施するためには、低ＳｉＯ2含有
量で且つ高被還元性の焼結鉱を使用することが不可欠で
あると言える。さらに、焼結鉱の製造の面でも、国内の
高炉の大半が内容積３０００ｍ3以上の大型高炉である
点を考慮すると、焼結操業には低ＳｉＯ2含有量で且つ
高被還元性の焼結鉱を安定して高い生産性で製造するこ
とが要求される。Therefore, it can be said that it is indispensable to use a sinter having a low SiO 2 content and a high reducibility in order to carry out a low silicon operation of a blast furnace accompanied by a large amount of pulverized coal injection. Furthermore, considering that most of the domestic blast furnaces are large blast furnaces with an internal volume of 3000 m 3 or more in terms of the production of sinter, the sintering operation has a low SiO 2 content and a high reducibility. Stable and highly productive production of sinter is required.
【０００７】しかし、一般に焼結鉱のＳｉＯ2含有量を
低くすると焼結過程でのスラグ生成量が減少して焼結鉱
の強度低下をきたすため、成品歩留まりが悪化して生産
性が低下する。したがって、焼結鉱の強度を確保し生産
性の低下を防止するためには、固体燃料粉（通常、粉コ
ークス）の配合比率を高めて焼成熱量を増大させること
が必要であるが、このように固体燃料粉の配合比率を高
めて焼成熱量を増大させると焼結鉱の被還元性が低下し
てしまう。つまり、一般に焼結鉱の低ＳｉＯ2化と高被
還元性及び高生産性は両立しない関係にあると言える。However, generally, when the SiO 2 content of the sintered ore is lowered, the amount of slag produced in the sintering process is reduced and the strength of the sintered ore is lowered, so that the product yield is deteriorated and the productivity is lowered. . Therefore, in order to secure the strength of the sinter and prevent the productivity from decreasing, it is necessary to increase the blending ratio of solid fuel powder (usually coke coke) to increase the calorific value. If the blending ratio of the solid fuel powder is increased and the calorific value of heat is increased, the reducibility of the sinter decreases. That is, in general, it can be said that the low SiO 2 content of the sinter and the high reducibility and high productivity are incompatible with each other.
【０００８】従来、低ＳｉＯ2含有量の焼結鉱の製造技
術に関して幾つかの提案がなされている。従来の低Ｓｉ
Ｏ2焼結鉱に関する提案は、主としてスラグ生成を制御
する技術に関するものであり、例えば、特公昭５８−１
１８０号公報には、配合原料に加える珪石および石灰石
を１ｍｍ未満に粉砕して造滓成分の反応性を高めること
により、造滓源の配合量を減らしても品質が適正に維持
された焼結鉱を製造できる技術が開示されている。[0008] Heretofore, some proposals have been made regarding the technology for producing a sinter having a low SiO 2 content. Conventional low Si
Proposals relating to O 2 sinter are mainly related to technology for controlling slag formation, and are disclosed in, for example, Japanese Patent Publication No. 58-1.
No. 180 discloses a sintering process in which the quality of silica stone and limestone added to the blending raw material is reduced to less than 1 mm to increase the reactivity of the slag component, so that the quality is properly maintained even if the amount of the slag source is reduced. Techniques for producing ore are disclosed.
【０００９】また、特開平７−３３１３４２号公報に
は、耐還元粉化性の良好な低ＳｉＯ2焼結鉱の製造方法
として、ＳｉＯ2濃度が３．０〜４．７重量％となるよ
うに配合した原料を高速撹拌羽根を内蔵した混合機で強
力に混合することにより、造粒に関与しない（すなわ
ち、核粒子にも付着粒子にもならない）粒子の量を低減
させる技術が開示されている。Further, Japanese Patent Laid-Open No. 7-331342 discloses a method for producing a low SiO 2 sinter having good resistance to reduction pulverization such that the SiO 2 concentration is 3.0 to 4.7% by weight. A technique for reducing the amount of particles not involved in granulation (that is, neither core particles nor adhered particles) is disclosed by vigorously mixing the raw material blended in (1) with a mixer with a built-in high-speed stirring blade. There is.
【００１０】さらに、特公平５−５９９７２号公報に
は、冷間強度、被還元性、耐還元粉化性の高い低ＳｉＯ
2焼結鉱の製造方法として、ＳｉＯ2含有量に応じた量の
ＣａＯ副原料を加え、針状カルシウム・フェライト主体
の組織を得ることによって、歩留りおよび品質を維持或
いは向上させながら低ＳｉＯ2焼結鉱を製造する技術が
開示されている。Further, Japanese Patent Publication No. 5-59972 discloses low SiO having high cold strength, reducibility and resistance to reduction powder.
2 As a method for producing sinter, by adding CaO auxiliary material in an amount corresponding to the SiO 2 content and obtaining a structure mainly composed of acicular calcium / ferrite, a low SiO 2 calcination while maintaining or improving yield and quality. Techniques for producing sinter are disclosed.
【００１１】[0011]
【発明が解決しようとする課題】しかし、これらの従来
技術はある程度の効果は得られるとしても、上述したよ
うな本質的な理由から、低ＳｉＯ2含有量の焼結鉱にお
いて被還元性や生産性を効果的に高めることは困難であ
る。However, even though these prior arts can obtain some effects, for the above-mentioned essential reasons, the reducibility and production of sinter having a low SiO 2 content are high. It is difficult to effectively increase sex.
【００１２】最近、国内でＳｉＯ2含有量が５．０重量
％以下の焼結鉱（通常の粗粒主体の配合原料を用いた焼
結鉱）を製造している代表的な焼結機による製造実績を
表１にＡ〜Ｉとして示す。このなかでＳｉＯ2含有量の
最低レベルはＧ機の４．６３重量％であり、また、焼結
鉱の被還元性を表すＪＩＳ−ＲＩ（ＪＩＳ還元率）の最
大レベルはＨ機の約７２．３％であるが、Ｇ機のＪＩＳ
−ＲＩは６８．４％、Ｈ機のＳｉＯ2含有量は４．９３
重量％である。また、他の焼結機の製造実績はＳｉＯ2
含有量が４．７〜５．０重量％で且つＪＩＳ−ＲＩが６
４〜７０％程度の水準に止まっている。また、生産率に
ついても、ＳｉＯ2含有量が４．９３重量％であるＨ機
が２．１Ｔ／ｈ／ｍ2、ＪＩＳ−ＲＩが６７．０％であ
るＩ機が１．８５Ｔ／ｈ／ｍ2である他は、１．０〜
１．７Ｔ／ｈ／ｍ2程度の水準に止まっている。[0012] Recently, by a typical sinter machine that produces sinter having a SiO 2 content of 5.0% by weight or less (a sinter using a general raw material mainly composed of coarse grains) in Japan The manufacturing results are shown in Table 1 as A to I. Among them, the minimum level of SiO 2 content is 4.63% by weight of the G machine, and the maximum level of JIS-RI (JIS reduction rate), which indicates the reducibility of sinter, is about 72% of that of the H machine. Although it is 0.3%, JIS of G machine
-RI is 68.4%, SiO 2 content of machine H is 4.93
% By weight. The manufacturing results of other sintering machines are SiO 2
Content is 4.7 to 5.0% by weight and JIS-RI is 6
It remains at the level of 4 to 70%. Also, regarding the production rate, the H machine with a SiO 2 content of 4.93 wt% is 2.1 T / h / m 2 , and the I machine with a JIS-RI of 67.0% is 1.85 T / h /. Other than m 2 , 1.0-
It remains at a level of about 1.7 T / h / m 2 .
【００１３】[0013]
【表１】 [Table 1]
【００１４】このように従来製造されている低ＳｉＯ２
焼結鉱は、ＳｉＯ２含有量：４．８重量％以下、ＪＩＳ
−ＲＩ：７２％以上、生産率：１．７Ｔ／ｈ／ｍ２以上
を満足するものではなく、この水準を満足する焼結鉱の
製造技術は未だ確立されていないと言える。したがって
本発明の目的は、このような従来技術の課題を解決し、
微粉炭多量吹込みを伴う高炉の低シリコン操業を可能と
する、低ＳｉＯ２含有量で且つ高被還元性、高生産率の
焼結鉱の製造方法を提供することにある。The low SiO 2 conventionally manufactured in this way
The sinter has a SiO 2 content of 4.8 wt% or less, JIS
-RI: 72% or more, production rate: 1.7 T / h / m 2 or more are not satisfied, and it can be said that a technology for producing a sintered ore satisfying this level has not been established yet. Therefore, the object of the present invention is to solve the problems of the prior art,
Low SiO 2 content, high reducibility, and high production rate that enable low silicon operation of blast furnace with large amount of pulverized coal injection
It is to provide a manufacturing method of sinter .
【００１５】[0015]
【課題を解決するための手段】本発明者らは、低ＳｉＯ
2含有量の焼結鉱において高被還元性および高生産率を
達成できる焼結鉱組織およびその焼結プロセスについて
検討を行い、その結果、低ＳｉＯ2含有量でありながら
高被還元性、高生産率の焼結鉱を得るためには、焼結原
料中への固体燃料粉の配合比率、固体燃料粉の燃焼性に
大きな影響を与える擬似粒子内での固体燃料粉の分布形
態を含めた擬似粒子構造、さらには、原料装入層高さ方
向での均一な熱量分布を得るための原料装入形態を適正
化することが重要であり、これら固体燃料粉の配合比
率、擬似粒子構造および原料装入形態を適正化して得ら
れた特定の焼結組織を有する焼結鉱、具体的には焼結組
織中のＦｅＯ量が所定のレベルまで低減化された焼結鉱
が高い被還元性と生産率を有することを見い出した。The present inventors have found that low SiO
2 in sintered ore content for sintered ore organization and its sintering process highly reducible and high production rates can be achieved performed study, the results, while a low SiO 2 content higher reducibility, high In order to obtain the sinter of the production rate, the mixing ratio of the solid fuel powder in the sintering raw material and the distribution form of the solid fuel powder in the pseudo particles that greatly affects the combustibility of the solid fuel powder were included. Pseudo-particle structure, further, it is important to optimize the raw material charging form in order to obtain a uniform heat quantity distribution in the raw material charging layer height direction, the mixing ratio of these solid fuel powder, pseudo-particle structure and Highly reducible sinter having a specific sinter structure obtained by optimizing the raw material charging form, specifically sinter having a FeO amount in the sinter structure reduced to a predetermined level. And found to have a production rate.
【００１６】本発明はこのような知見に基づきなされた
もので、その特徴は以下の通りである。 The present invention has been made on the basis of such knowledge, and its features are as follows .
【００１７】[1] 粒径が０．１２５ｍｍ以下の粒子の割
合が３０重量％未満であって、成品焼結鉱のＳｉＯ２含
有量が４．８重量％以下になるように調整された配合原
料をドラムミキサーまたは皿型造粒機で１次造粒する工
程と、該工程で得られた１次造粒物に固体燃料粉の全量
を加えてドラムミキサーまたは皿型造粒機で２次造粒
し、固体燃料粉で被覆された擬似粒子を得る工程と、該
工程で得られた擬似粒子を焼結機パレット上に、擬似粒
子の粒度が原料装入層高さ方向で下層側＞上層側となる
ような粒度分布を有する状態に装入する工程と、該原料
装入層を焼結する工程とを有することを特徴とするＳｉ
Ｏ２含有量が低い焼結鉱の製造方法。 [1] A composition adjusted such that the proportion of particles having a particle size of 0.125 mm or less is less than 30% by weight, and the SiO 2 content of the product sinter is 4.8% by weight or less. The step of primary granulating the raw material with a drum mixer or a dish granulator, and the secondary granulation with a drum mixer or a dish granulator by adding the total amount of solid fuel powder to the primary granule obtained in the step The step of granulating and obtaining the pseudo particles coated with the solid fuel powder, and the pseudo particles obtained in the step are placed on a sintering machine pallet.
The grain size of the child is from the lower layer side to the upper layer side in the height direction of the raw material charging layer.
Si having a step of charging into a state having such a particle size distribution and a step of sintering the raw material charging layer
A method for producing a sinter having a low O 2 content.
【００１８】[2] 粒径が０．１２５ｍｍ以下の粒子の割
合が３０重量％未満であって、成品焼結鉱のＳｉＯ２含
有量が４．８重量％以下になるように調整された配合原
料を、全固体燃料粉のうちの３０重量％未満の固体燃料
粉とともにドラムミキサーまたは皿型造粒機で１次造粒
する工程と、該工程で得られた１次造粒物に固体燃料粉
の残量分を加えてドラムミキサーまたは皿型造粒機で２
次造粒し、固体燃料粉で被覆された擬似粒子を得る工程
と、該工程で得られた擬似粒子を焼結機パレット上に、
擬似粒子の粒度が原料装入層高さ方向で下層側＞上層側
となるような粒度分布を有する状態に装入する工程と、
該原料装入層を焼結する工程とを有することを特徴とす
るＳｉＯ２含有量が低い焼結鉱の製造方法。 [2] A composition in which the proportion of particles having a particle size of 0.125 mm or less is less than 30% by weight, and the SiO 2 content of the product sintered ore is adjusted to 4.8% by weight or less. A step of primary granulating the raw material with a solid fuel powder of less than 30% by weight of the total solid fuel powder in a drum mixer or a dish granulator, and a solid fuel in the primary granule obtained in the step Add the remaining amount of powder and use a drum mixer or dish granulator to do 2
Next step of granulating, to obtain pseudo particles coated with solid fuel powder, and the pseudo particles obtained in the step on a sinter machine pallet,
The particle size of the pseudo particles is the lower layer side in the height direction of the raw material charging layer> the upper layer side
Charging into a state having a particle size distribution such that
And a step of sintering the raw material charging layer, the method for producing a sintered ore having a low SiO 2 content.
【００１９】[3] 上記[1]または[2]の製造方法におい
て、２次造粒工程で得られた擬似粒子を、原料装入装置
の原料供給部の下方に下向き傾斜状に設けられた原料装
入用シュートであって、焼結機パレット幅方向と略平行
なスリットをシュート上下方向で並列的に複数形成し、
該スリットの幅をシュート上部側ほど狭めた構造を有す
るスクリーン状シュートを介して、焼結機パレット上に
装入することにより、擬似粒子の粒度が原料装入層高さ
方向で下層側＞上層側となるような粒度分布を有する状
態とすることを特徴とするＳｉＯ２含有量が低い焼結鉱
の製造方法。 [3] In the manufacturing method according to the above [1] or [2] , the pseudo particles obtained in the secondary granulation step are provided in a downward inclined shape below the raw material supply section of the raw material charging device. A chute for raw material charging, a plurality of slits substantially parallel to the width direction of the pallet of the sintering machine are formed in parallel in the vertical direction of the chute,
By charging the slits on the sinter machine pallet through a screen-shaped chute having a structure in which the width of the slit is narrowed toward the upper side of the chute, the particle size of the pseudo particles is adjusted to the height of the raw material charging layer.
With a particle size distribution such that the lower layer side> the upper layer side in the direction
A method for producing a sinter having a low SiO 2 content, which is characterized in that
【００２０】[4] 上記[1]〜[3]のいずれかの製造方法に
おいて、固体燃料粉の全量が成品焼結鉱１ｔ当たり４４
ｋｇ以下であることを特徴とするＳｉＯ２含有量が低い
焼結鉱の製造方法。 [4] In the manufacturing method according to any one of the above [1] to [3], the total amount of solid fuel powder is 44 per 1 t of the product sintered ore.
A method for producing a sinter having a low SiO 2 content, which is less than or equal to kg.
【００２１】[0021]
【発明の実施の形態】焼結鉱の被還元性が低下する主た
る原因は、焼結過程において過剰な溶融緻密組織が生成
されるためである。すなわち、焼結過程では下記(1)式
および(2)式に示すように酸化鉄が固体燃料中のＣによ
り部分的に還元された後、シリカ分と反応し、難還元性
の融液状ファイヤライトが生成するが、この融液状ファ
イヤライトが過剰に生成すると焼結組織が溶融緻密組織
となる。そして、焼結組織がこのような溶融緻密組織に
なると還元ガスの組織内拡散が阻害され、被還元性は低
下する。従来の焼結プロセスでは、固体燃料粉が擬似粒
子の内部に内装（焼結原料と同時に造粒されることによ
り、擬似粒子内部全体に固体燃料粉が分布した状態）さ
れているため上記融液状ファイヤライトが過剰に生成
し、焼結組織が著しい溶融緻密組織となるために被還元
性の低下を生じていたものである。
Ｆｅ2Ｏ3（鉱石）＋Ｃ（固体燃料）＝２ＦｅＯ＋ＣＯ … (1)
２ＦｅＯ＋ＳｉＯ2（脈石）＝２ＦｅＯ・ＳｉＯ2（ファイヤライト） … (2) BEST MODE FOR CARRYING OUT THE INVENTION The main cause of the reduction in the reducibility of sinter is that an excessive molten and dense structure is generated during the sintering process. That is, in the sintering process, as shown in the following formulas (1) and (2), after iron oxide is partially reduced by C in the solid fuel, it reacts with the silica content, and a non-reducing melt fire Although light is generated, when the melted firelite is excessively generated, the sintered structure becomes a molten and dense structure. When the sintered structure becomes such a molten and dense structure, diffusion of the reducing gas in the structure is hindered and the reducibility is reduced. In the conventional sintering process, the solid fuel powder is internally contained inside the pseudo particles (the solid fuel powder is distributed throughout the pseudo particles by being granulated at the same time as the sintering raw material). This is because the amount of firelite is excessively generated and the sintered structure becomes a remarkably molten and dense structure, resulting in a reduction in the reducibility. Fe 2 O 3 (ore) + C (solid fuel) = 2FeO + CO (1) 2FeO + SiO 2 (gangue) = 2FeO · SiO 2 (firelite) (2)
【００２２】したがって、焼結鉱の被還元性を確保する
には焼結組織を溶融緻密組織ではなく多孔質組織とする
必要があり、このような多孔質組織を得るためには、配
合原料に添加する固体燃料粉量を相対的に減らす必要が
ある。しかし、従来の焼結プロセスでは、固体燃料粉の
添加量を減らすと焼結に必要な燃焼熱量が不足し、特に
原料装入層の上層部での焼結熱量が不足してむら焼けを
生じる結果、成品歩留まりが悪化して高生産率が達成で
きないという問題があった。Therefore, in order to secure the reducibility of the sintered ore, it is necessary to make the sintered structure a porous structure rather than a molten and dense structure. It is necessary to relatively reduce the amount of solid fuel powder added. However, in the conventional sintering process, if the amount of solid fuel powder added is reduced, the amount of combustion heat required for sintering is insufficient, and in particular, the amount of sintering heat in the upper layer of the raw material charging layer is insufficient and uneven burning occurs. As a result, there is a problem that the product yield is deteriorated and a high production rate cannot be achieved.
【００２３】このような問題に対して本発明では、固体
燃料粉の配合比率を低減化した上で、擬似粒子における
固体燃料粉の効率的な燃焼と原料装入層高さ方向での均
一な熱量分布を確保するために、擬似粒子内での固体燃
料粉の分布形態を含めた擬似粒子構造と原料装入層高さ
方向での原料装入形態を適正化し、ＦｅＯ含有量が６．
０重量％以下のレベルまで低減した多孔質の焼結組織を
得ることにより、低ＳｉＯ2焼結鉱の高被還元性と高生
産率を実現した。In order to solve such a problem, in the present invention, the mixing ratio of the solid fuel powder is reduced, and then the efficient burning of the solid fuel powder in the pseudo particles and the uniform distribution in the height direction of the raw material charging layer are carried out. In order to secure the heat quantity distribution, the pseudo particle structure including the distribution form of the solid fuel powder in the pseudo particles and the raw material charging shape in the raw material charging layer height direction are optimized, and the FeO content is 6.
By obtaining a porous sintered structure reduced to a level of 0% by weight or less, high reducibility and high production rate of low SiO 2 sinter were realized.
【００２４】このように焼結組織中のＦｅＯ量が６．０
重量％以下まで低減化された高被還元性の低ＳｉＯ2焼
結鉱を、特に炉内ガス発生量が多く炉内通気性の確保が
不可欠である微粉炭多量吹込みを伴う高炉の低シリコン
操業において高炉原料として使用すれば、炉内通気性を
顕著に改善することができ、同高炉操業を安定して実施
することができる。Thus, the amount of FeO in the sintered structure is 6.0.
Highly reducible low SiO 2 sinter reduced to less than 10% by weight, especially low silicon gas in blast furnace with large injection of pulverized coal for which in-furnace air permeability is indispensable because of large gas generation in the furnace When used as a blast furnace raw material in the operation, the air permeability in the furnace can be remarkably improved, and the blast furnace operation can be stably performed.
【００２５】以下、本発明の詳細をその実施形態ととも
に説明する。本発明の焼結鉱は、粒径が０．１２５ｍｍ
以下の粒子の割合が３０重量％未満である通常の粗粒主
体の配合原料を造粒して擬似粒子を形成し、これを焼成
することにより得られる焼結鉱である。The details of the present invention will be described below together with the embodiments thereof. The sintered ore of the present invention has a particle size of 0.125 mm
It is a sinter obtained by granulating a general raw material mainly composed of coarse particles having a ratio of the following particles of less than 30% by weight to form pseudo particles, and firing the pseudo particles.
【００２６】図１は本発明の焼結鉱の製造フローの一例
を示しており、Ｂ粉１、返鉱３、媒溶材４等の配合原料
（場合によっては、さらに固体燃料粉２の一部を添加）
を１次ドラムミキサー５（または１次皿型造粒機）に装
入し、適量の水分を加えて調湿、混合、造粒して１次造
粒物を得る。次いで、この１次造粒物に固体燃料粉２を
加え、２次ドラムミキサー６（または２次皿型造粒機）
で２次造粒することにより、表層部に固体燃料粉が被覆
（外装）された擬似粒子を形成する。この擬似粒子は図
示しない原料装入装置を介して焼結機７のパレット上に
装入されるが、この際、焼結時に原料装入層高さ方向で
均一な熱量分布が得られるようにするため、擬似粒子が
層高方向に所定の粒度偏析を持った原料装入層を形成す
る。FIG. 1 shows an example of the production flow of the sinter according to the present invention, in which mixed raw materials such as B powder 1, return ore 3 and solvent material 4 (in some cases, a part of solid fuel powder 2 is further added). Added)
Is charged into a primary drum mixer 5 (or a primary dish type granulator), and an appropriate amount of water is added to adjust the humidity, mix and granulate to obtain a primary granulated product. Then, the solid fuel powder 2 is added to this primary granulation product, and the secondary drum mixer 6 (or secondary dish granulator) is added.
Secondary granulation is performed to form pseudo particles in which solid fuel powder is coated (exterior) on the surface layer portion. The pseudo particles are charged on the pallet of the sintering machine 7 via a raw material charging device (not shown). At this time, a uniform heat quantity distribution is obtained in the height direction of the raw material charging layer during sintering. Therefore, the pseudo particles form a raw material charging layer having a predetermined particle size segregation in the layer height direction.
【００２７】前記Ｂ粉１は粒径が０．１２５ｍｍ以下の
粒子の割合が３０重量％未満の通常の焼結用粉鉱石であ
って、例えば、ＭＢＲ、カラジャス、ＣＶＧに代表され
る低ＳｉＯ2含有鉱石を単銘柄で若しくは複数銘柄を適
宜配合して用いる。このＢ粉１は焼結鉱のＳｉＯ2含有
量が４．８重量％以下、Ｆｅ含有量が５６重量％以上に
なるように調整して用いる。一般に、焼結鉱中のＦｅ含
有量が５６重量％未満では、焼結過程で脈石と石灰石が
反応してカルシウムシリケート系スラグが増加し、これ
が被還元鉄酸化物であるヘマタイト、カルシウムフェラ
イト、マグネタイトなどの組織を覆った焼結緻密組織と
なり易いため好ましくない。固体燃料粉２としては一般
に粉コークスが用いられるが、これ以外にチャー、無煙
炭、石油コークス、石炭を用いることができ、また、こ
れらの混合物を用いてもよい。The B powder 1 is a normal powdered ore for sintering in which the proportion of particles having a particle size of 0.125 mm or less is less than 30% by weight, and for example, low SiO 2 typified by MBR, carajas and CVG. The contained ore is used as a single brand or as a mixture of multiple brands as appropriate. This B powder 1 is used after being adjusted so that the SiO 2 content of the sintered ore is 4.8% by weight or less and the Fe content is 56% by weight or more. Generally, when the Fe content in the sinter is less than 56% by weight, the gangue and the limestone react with each other in the sintering process to increase calcium silicate-based slag, which is a reducible iron oxide such as hematite, calcium ferrite, It is not preferable because it tends to be a sintered dense structure covering a structure such as magnetite. As the solid fuel powder 2, powder coke is generally used, but char, anthracite, petroleum coke, coal may be used in addition to this, or a mixture thereof may be used.
【００２８】先に述べたように、本発明の焼結鉱を製造
する上で固体燃料粉２の配合量と擬似粒子内における分
布形態が非常に重要である。先ず、固体燃料粉２の配合
量は、焼結時におけるスラグ生成量を極力抑制して焼結
組織の多孔質化を図るために必要最低限にとどめる必要
があり、具体的には固体燃料粉の配合量は成品焼結鉱１
ｔ当たり４４ｋｇ以下とすることが必要である。固体燃
料粉の配合量が成品焼結鉱１ｔ当たり４４ｋｇを超える
と、投入熱量が過剰となるため焼結組織が溶融緻密組織
となり易く、成品焼結鉱中の所望のＦｅＯ量（６．０重
量％以下）が得られず、ＪＩＳ−ＲＩ：７２％以上の高
被還元性が達成できない。As described above, the amount of the solid fuel powder 2 and the distribution form in the pseudo particles are very important for producing the sinter of the present invention. First, the amount of the solid fuel powder 2 to be blended must be minimized in order to minimize the amount of slag produced during sintering and to make the sintered structure porous. The compounding amount of is a product sintered ore 1
It is necessary to make it 44 kg or less per t. If the amount of the solid fuel powder blended exceeds 44 kg per 1 t of the product sintered ore, the amount of heat input becomes excessive and the sintered structure tends to be a molten and dense structure, and the desired amount of FeO in the product sintered ore (6.0 wt. % Or less), and high reducibility of JIS-RI: 72% or more cannot be achieved.
【００２９】また、固体燃料粉２の擬似粒子内での分布
形態については、固体燃料粉の大部分が擬似粒子の表層
部に外装（被覆）される必要がある。このように固体燃
料粉を擬似粒子に対して外装化する第１の理由は、固体
燃料粉の多くを擬似粒子表層部に存在させることで固体
燃料粉の燃焼性を向上させ、固体燃料粉の配合量の低減
化に伴う焼成熱量の不足を補うことにある。また、第２
の理由は、固体燃料粉が燃焼する際の擬似粒子内部への
過剰な熱供給を抑制し、これにより上記固体燃料粉配合
量の低減化と相俟って焼結組織が溶融緻密組織になるこ
とを防止し、多孔質ヘマタイトや多孔質カルシウムフェ
ライトの鉱物相が多量に生成した多孔質の焼結組織を得
るようにするためである。Regarding the distribution form of the solid fuel powder 2 in the pseudo particles, most of the solid fuel powder needs to be coated (covered) on the surface layer of the pseudo particles. The first reason for coating the solid fuel powder with respect to the pseudo particles in this way is to improve the combustibility of the solid fuel powder by allowing most of the solid fuel powder to exist in the surface layer of the pseudo particles, and This is to make up for the shortage of the calorific value due to the reduction of the compounding amount. Also, the second
The reason is that the excessive heat supply to the inside of the pseudo particles when the solid fuel powder is burned is suppressed, and in combination with the reduction of the solid fuel powder blending amount, the sintered structure becomes a molten and dense structure. This is to prevent this and obtain a porous sintered structure in which a large amount of the mineral phase of porous hematite or porous calcium ferrite is generated.
【００３０】固体燃料粉２は、２次造粒工程で実質的に
全量を擬似粒子表層部に外装してもよいが、一部を１次
造粒工程で添加し、残量分を２次造粒工程で擬似粒子表
層部に外装するようにしてもよい。但し、上述した固体
燃料粉の外装化による効果を確実に得るためには、固体
燃料粉２の一部を１次造粒工程で添加する場合の添加量
は固体燃料粉の全配合量の３０重量％未満とし、残りの
７０重量％以上の固体燃料粉は２次造粒工程で擬似粒子
の表層部に外装することが必要である。また、１次造粒
工程での固体燃料粉の添加量が３０重量％以上になる
と、焼結過程で擬似粒子内部に拡散する酸素量に対して
擬似粒子内の固体燃料粉量の比率が高過ぎ、固体燃料粉
の燃焼が著しく遅くなる結果、焼結時間が延び、生産率
の低下を招くため好ましくない。Substantially all of the solid fuel powder 2 may be coated on the surface layer of the pseudo particles in the secondary granulation process, but a part of the solid fuel powder 2 is added in the primary granulation process, and the remaining amount is secondary. You may make it coat | cover on a pseudo particle surface layer part in a granulation process. However, in order to surely obtain the above-mentioned effect by the exteriorization of the solid fuel powder, the addition amount when a part of the solid fuel powder 2 is added in the primary granulation step is 30% of the total mixing amount of the solid fuel powder. It is necessary to coat less than 70% by weight and the remaining 70% by weight or more of solid fuel powder on the surface layer of the pseudo particles in the secondary granulation step. Further, when the amount of solid fuel powder added in the primary granulation step is 30% by weight or more, the ratio of the amount of solid fuel powder in the pseudo particles to the amount of oxygen diffused inside the pseudo particles during the sintering process becomes high. As a result, the combustion of the solid fuel powder is remarkably delayed, resulting in a longer sintering time and a lower production rate, which is not preferable.
【００３１】本発明の焼結鉱の製造において固体燃料粉
を擬似粒子の表層部に外装（被覆）するもう一つの狙い
は、擬似粒子を焼結機パレット上に粒度偏析装入（層高
方向で粒度分布をもつような装入）することとの組み合
わせにより、原料装入層高さ方向で均一な熱量分布を得
ることにある。In the production of the sintered ore according to the present invention, another aim of covering (coating) the solid fuel powder on the surface layer portion of the pseudo particles is to charge the pseudo particles on the sinter machine pallet by segregating the particle size (in the direction of the bed height). In order to obtain a uniform heat quantity distribution in the height direction of the raw material charging layer, it is possible to obtain a uniform heat amount distribution in combination with the charging with a particle size distribution.
【００３２】一般に、焼結時の原料装入層はその高さ方
向における下層部側ほど熱レベルが高い傾向にある。す
なわち、原料装入層の下層部側はコークスの燃焼熱に加
えて上中層部からの高温燃焼ガスが流入するため熱レベ
ルが高く、熱余剰を生じやすい。一方、原料装入層の上
層部側はコークスの燃焼と同時に室温の空気を吸い込む
ため熱レベルが低く、熱不足を生じ易い。したがって、
擬似粒子が受ける熱レベルを原料装入層の高さ方向で均
一にするには、原料装入層の上層部側には固体燃料粉濃
度の高い擬似粒子を、また、下層部側には固体燃料粉濃
度の低い擬似粒子を装入することが必要となる。In general, the raw material charging layer during sintering tends to have a higher heat level toward the lower layer side in the height direction. That is, on the lower layer side of the raw material charging layer, the high-temperature combustion gas from the upper middle layer flows in addition to the combustion heat of the coke, so the heat level is high, and thermal surplus is likely to occur. On the other hand, the upper layer side of the raw material charging layer sucks air at room temperature at the same time as the coke burns, so the heat level is low, and heat shortage easily occurs. Therefore,
In order to make the heat level received by the pseudo particles uniform in the height direction of the raw material charging layer, pseudo particles with high solid fuel powder concentration are used on the upper layer side of the raw material charging layer, and solid particles on the lower layer side. It is necessary to charge pseudo particles having a low fuel powder concentration.
【００３３】ここで、擬似粒子の固体燃料粉濃度は、固
体燃料粉が擬似粒子に内装されている場合には擬似粒子
の粒径に拘りなくほぼ一定であるが、固体燃料粉が擬似
粒子の表層部に外装（被覆）されている場合には、擬似
粒子表面を被覆する固体燃料粉の重量は擬似粒子の表面
積に比例（すなわち、擬似粒子径Ｒの２乗に比例）する
と考えられ、また、擬似粒子の重量は擬似粒子径Ｒの３
乗に比例すると考えられるから、擬似粒子の単位重量当
たりの固体燃料粉濃度はＲ2／Ｒ3に比例する、つまり擬
似粒子径に反比例すると考えられる。したがって、固体
燃料粉で被覆された擬似粒子を原料装入層の上層部側か
ら下層部側にかけて粒子径が漸次増加するような粒度偏
析した状態（すなわち、擬似粒子の粒度が原料装入層高
さ方向で下層側＞上層側となるような粒度分布）に装入
すれば、固体燃料粉濃度が原料装入層の上層部側で高
く、下層部側で低い極めて理想的な固体燃料粉の濃度分
布を得ることが可能になると考えられる。Here, the solid fuel powder concentration of the pseudo particles is almost constant irrespective of the particle size of the pseudo particles when the solid fuel powder is contained in the pseudo particles, but the solid fuel powder is the pseudo particles. When the surface layer is covered (coated), the weight of the solid fuel powder coating the surface of the pseudo particles is considered to be proportional to the surface area of the pseudo particles (that is, proportional to the square of the pseudo particle diameter R). , The weight of the pseudo particles is 3 of the pseudo particle diameter R.
Since it is considered to be proportional to the power, the solid fuel powder concentration per unit weight of pseudo particles is considered to be proportional to R 2 / R 3 , that is, inversely proportional to the pseudo particle size. Therefore, the state in which the pseudo particles coated with the solid fuel powder are segregated so that the particle diameter gradually increases from the upper layer side to the lower layer side of the raw material charging layer (that is, the particle size of the pseudo particles is higher than the raw material charging layer height) If the particle size distribution is such that the lower layer side> the upper layer side in the vertical direction), the concentration of solid fuel powder is high on the upper layer side of the raw material charging layer and low on the lower layer side. It is considered possible to obtain the concentration distribution.
【００３４】本発明者らは上記の点を確認するために、
図１に示す製造フローで造粒した擬似粒子（表層部が固
体燃料粉で被覆された擬似粒子）を２次ドラムミキサー
出口でサンプリングし、擬似粒子の粒度別（平均粒度）
の固体燃料粉濃度（擬似粒子の単位重量当たりの固体燃
料粉濃度）を分析した。また、比較のために固体燃料粉
の全量を１次ドラムミキサーで焼結原料に添加し、造粒
して得られた固体燃料粉内装型の擬似粒子（２次ドラム
ミキサーでは固体燃料粉は添加せず）についても、同様
に粒度別の固体燃料粉濃度を分析した。In order to confirm the above points, the present inventors have
Pseudo-particles granulated by the manufacturing flow shown in FIG. 1 (pseudo-particles whose surface layer is coated with solid fuel powder) are sampled at the outlet of the secondary drum mixer, and the pseudo-particles are classified by particle size (average particle size).
The solid fuel powder concentration (solid fuel powder concentration per unit weight of the pseudo particles) was analyzed. For comparison, the solid fuel powder-containing pseudo particles obtained by adding the whole amount of the solid fuel powder to the sintering raw material with the primary drum mixer and granulating it (the solid fuel powder was added with the secondary drum mixer). Similarly, the solid fuel powder concentration for each particle size was also analyzed.
【００３５】図２はその結果を示すもので、固体燃料粉
内装型の擬似粒子では、擬似粒子の単位重量当たりの固
体燃料粉濃度は粒子径に拘りなくほぼ一定の値を示して
いるのに対し、表層部が固体燃料粉で被覆された固体燃
料粉外装型の擬似粒子では、擬似粒子の単位重量当たり
の固体燃料粉濃度は擬似粒子径に反比例していることが
確認できた。FIG. 2 shows the results, and in the solid fuel powder-containing pseudo particles, the solid fuel powder concentration per unit weight of the pseudo particles shows a substantially constant value regardless of the particle diameter. On the other hand, in the solid fuel powder exterior type pseudo particles in which the surface layer portion was coated with the solid fuel powder, it was confirmed that the solid fuel powder concentration per unit weight of the pseudo particles was inversely proportional to the pseudo particle diameter.
【００３６】したがって、擬似粒子を固体燃料粉外装型
とし、且つこれを原料装入層の上層部側から下層部側に
かけて擬似粒子径が漸次増加するような粒度偏析状態、
すなわち、擬似粒子の粒度が原料装入層高さ方向で下層
側＞上層側となるような粒度分布を有する状態に装入す
れば、原料装入層の上層部側ほど固体燃料粉濃度が高い
固体燃料粉濃度分布を得ることが可能となる。Therefore, the pseudo particles are of the solid fuel powder exterior type, and the particle size segregation state in which the pseudo particle diameter gradually increases from the upper layer side to the lower layer side of the raw material charging layer,
That is, if the pseudo-particles are charged in a state where the particle size distribution is such that the particle size of the pseudo particles is lower layer side> upper layer side in the height direction of the raw material charging layer, the solid fuel powder concentration is higher on the upper layer side of the raw material charging layer. It is possible to obtain the solid fuel powder concentration distribution.
【００３７】なお、擬似粒子の粒度が原料装入層高さ方
向で下層側＞上層側となるような粒度分布とは、装入さ
れた個々の擬似粒子の粒径が常に原料装入層高さ方向で
下層側＞上層側の関係にあるという厳密な意味ではな
く、また、以下に述べるような具体的な原料装入方法や
装置的な構成からしても、そのような厳密な意味での粒
度分布を得ることは事実上不可能である。したがって、
本発明が条件とする上記擬似粒子の粒度分布は、原料装
入層高さ方向全体において擬似粒子の平均粒径が下層側
＞上層側の関係を満足するような粒度分布を意味してい
る。The particle size distribution in which the particle size of the pseudo particles is such that the lower layer side> the upper layer side in the height direction of the raw material charging layer means that the particle size of each of the charged pseudo particles is always the height of the raw material charging layer. The lower layer side> the upper layer side in the vertical direction is not a strict meaning, and also in terms of a specific raw material charging method and a device-like configuration as described below, such a strict meaning is also present. It is virtually impossible to obtain a particle size distribution of. Therefore,
The particle size distribution of the above pseudo particles, which is a condition of the present invention, means a particle size distribution in which the average particle size of the pseudo particles satisfies the relationship of lower layer side> upper layer side in the entire height direction of the raw material charging layer.
【００３８】本発明の焼結鉱の製造では、上述のように
擬似粒子を原料装入層の上層部側から下層部側にかけて
擬似粒子径が漸次増加するような粒度偏析状態に装入す
るために、図３に示すような粒度偏析装入用のスクリー
ン状シュート８を介して擬似粒子を焼結機パレット１２
上に装入する。このスクリーン状シュート８は、原料装
入装置における原料供給部９の下方に下向き傾斜状に設
けられるもので、焼結機パレット幅方向と略平行なスリ
ット１０をシュート上下方向で並列的に複数形成し、こ
れらスリット１０の幅をシュート上部側ほど狭めた構造
を有している。In the production of the sintered ore of the present invention, since the pseudo particles are charged in a particle size segregation state in which the pseudo particle diameter gradually increases from the upper layer side to the lower layer side of the raw material charging layer as described above. Then, the pseudo particles are transferred to the sintering machine pallet 12 through the screen-shaped chute 8 for charging the particle size segregation as shown in FIG.
Charge on top. The screen-shaped chute 8 is provided below the raw material supply unit 9 in the raw material charging device in a downwardly inclined shape, and a plurality of slits 10 substantially parallel to the width direction of the pallet of the sintering machine are formed in parallel in the vertical direction of the chute. However, it has a structure in which the width of these slits 10 is narrowed toward the upper side of the chute.
【００３９】このようなスクリーン状シュート８を介し
て擬似粒子を焼結機パレット１２上に装入する際、原料
供給部９から払い出されてスクリーン状シュート８上を
滑り落ちる擬似粒子は、スリット１０の幅がシュート上
部側ほど小さいため、スリット１０を通じて焼結機パレ
ット１２上に落下する際に粒径に応じて篩い分けされ、
粒径の大きい擬似粒子ほど焼結機パレット１２の原料装
入始端側に装入される。この結果、擬似粒子装入後の原
料装入層は上層部側ほど擬似粒子径が小さく、層高方向
で擬似粒子が粒度偏析した状態となる。When the pseudo particles are loaded on the sinter machine pallet 12 through the screen chute 8 as described above, the pseudo particles discharged from the raw material supply unit 9 and sliding down on the screen chute 8 are slits 10. Has a smaller width on the upper side of the chute, so when it falls through the slit 10 onto the sinter machine pallet 12, it is sieved according to the particle size,
Pseudo particles having a larger particle size are charged to the raw material charging start end side of the sinter machine pallet 12. As a result, the raw material charging layer after charging the pseudo particles has a smaller pseudo particle diameter toward the upper layer side, and the pseudo particles are in a state of particle size segregation in the layer height direction.
【００４０】なお、上記スクリーン状シュート８の一般
的な構造としては、シュート本体が索状体（例えば、ワ
イヤロープ等）または棒状体（例えば、中実または中空
ロッド等）からなる焼結機パレット幅方向に略平行な複
数のスクリーン構成部材１１から構成され、隣接するス
クリーン構成部材１１間の間隙が前記スリット１０を構
成する。As a general structure of the screen-shaped chute 8, a sinter machine pallet having a chute body made of a cord-shaped body (for example, wire rope) or a rod-shaped body (for example, solid or hollow rod) is used. It is composed of a plurality of screen constituent members 11 substantially parallel to the width direction, and the gap between the adjacent screen constituent members 11 constitutes the slit 10.
【００４１】これらスクリーン構成部材１１は固定式の
構造でもよいが、場合によっては、各スクリーン構成部
材１１をその長手方向で移動可能とするとともに、その
移動の際に部材表面に付着した擬似粒子を掻き落とすた
めの掻き取り手段（例えば、スクリーン構成部材１１が
挿通するガイド孔を有する付着物掻き取り兼用のガイド
部材）を有する構造とし、スクリーン構成部材１１を適
宜移動させ、その表面に付着した擬似粒子を前記掻き取
り手段で掻き落とすことにより、擬似粒子によるスリッ
ト１０の閉塞を防止するようにしてもよい。These screen constituting members 11 may have a fixed structure, but in some cases, each screen constituting member 11 can be moved in the longitudinal direction thereof, and at the time of the movement, pseudo particles adhering to the member surface are removed. A structure having a scraping means for scraping off (for example, a guide member that also has a guide hole through which the screen constituent member 11 is inserted and also serves as a scraped material scraping member) is provided, and the screen constituent member 11 is appropriately moved to make a pseudo-stick attached to the surface thereof. The particles may be scraped off by the scraping means to prevent the slit 10 from being blocked by the pseudo particles.
【００４２】前記スリット１０は、シュート最上部側の
スリット幅をｗ1、シュート最下部側のスリット幅をｗn
とした場合に、例えばスリット幅ｗ1からスリット幅ｗn
までの大きさをスリット毎に連続的に変えてもよいし、
或いは隣接するいくつかのスリット幅を同じにして、ス
リット幅の大きさをｗ1…ｗ1，ｗ2…ｗ2，…のように段
階的に変えてもよく、その態様は任意である。したがっ
て、スリット１０の幅がシュート上部側ほど小さいとい
う上記構成には、これら各種態様が含まれる。また、擬
似粒子が滑落するスクリーン状シュート上面の形状は、
直線状、凹湾曲状等のいずれでもよい。The slit 10 has a slit width w 1 on the uppermost side of the chute and a slit width wn on the lowermost side of the chute.
In this case, for example, slit width w 1 to slit width wn
The size up to may be changed continuously for each slit,
Alternatively, some adjacent slit widths may be the same, and the size of the slit width may be changed stepwise like w 1 ... W 1 , w 2 ... W 2 , ..., The mode is arbitrary. Therefore, the above configuration in which the width of the slit 10 is smaller toward the upper side of the chute includes these various aspects. Also, the shape of the upper surface of the screen chute on which the pseudo particles slide down is
It may be linear, concave curved, or the like.
【００４３】次に、擬似粒子の好ましい粒度と上述した
粒度偏析装入による擬似粒子の原料装入層高さ方向にお
ける好ましい粒度分布について説明する。擬似粒子の粒
度範囲は１ｍｍ〜１０ｍｍの範囲とすること（但し、一
部不可避的に造粒されないで存在する微粉成分を除く）
が好ましい。この擬似粒子径が１ｍｍ未満では焼結性は
向上するものの、擬似粒子粒度が細かすぎるため原料装
入層の上層部側の通気性が悪化し、操業度の低下を招き
易い。一方、擬似粒子径が１０ｍｍを超えると、外装さ
れた固体燃料粉の燃焼熱が擬似粒子内部まで届かず、十
分が焼成ができなくなる。Next, the preferable particle size of the pseudo particles and the preferable particle size distribution of the pseudo particles in the height direction of the raw material charging layer due to the above-described particle size segregation charging will be described. The particle size range of the pseudo particles should be in the range of 1 mm to 10 mm (however, except for some fine powder components that are inevitably present without being granulated).
Is preferred. If the pseudo particle size is less than 1 mm, the sinterability is improved, but since the pseudo particle size is too small, the air permeability of the upper layer side of the raw material charging layer is deteriorated, and the operation rate is likely to be lowered. On the other hand, if the pseudo particle diameter exceeds 10 mm, the heat of combustion of the solid fuel powder that has been packaged does not reach the inside of the pseudo particle, and sufficient firing cannot be performed.
【００４４】また、焼結機パレット上に装入される擬似
粒子の層高方向での粒度分布としては、原料装入層の上
層部側（原料装入層を層高方向で２分した時の上層側部
分）の平均擬似粒子径が１ｍｍ〜３ｍｍ、原料装入層の
下層部側（原料装入層を層高方向で２分した時の下層側
部分）の平均擬似粒子径が３ｍｍ超〜１０ｍｍであるこ
とが好ましい。ここで、原料装入層の上層部側と下層部
側の境界平均擬似粒子径を３ｍｍとしたのは、図２に示
されるように擬似粒子の固体燃料粉濃度は粒子径が３ｍ
ｍを超える領域では低位安定しており、したがって、こ
のような粒子径の擬似粒子を原料装入層の下層部側に配
置することにより、原料装入層の上中層部からの高温燃
焼ガスが流入して熱レベルが上昇しても、焼結反応が抑
えられて過剰な融液生成が抑制されるためである。The particle size distribution of the pseudo particles charged on the sinter machine pallet in the bed height direction is as follows: when the raw material charge layer is divided into two in the bed height direction. (Upper layer side portion) has an average pseudo particle size of 1 mm to 3 mm, and the average pseudo particle diameter on the lower layer side of the raw material charging layer (lower layer side portion when the raw material charging layer is bisected in the layer height direction) exceeds 3 mm. It is preferably 10 mm. Here, the boundary average pseudo-particle diameter on the upper layer side and the lower layer side of the raw material charging layer is set to 3 mm, because the solid fuel powder concentration of the pseudo particles is 3 m as shown in FIG.
It is low and stable in the region exceeding m. Therefore, by arranging the pseudo particles having such a particle size on the lower layer side of the raw material charging layer, the high temperature combustion gas from the upper middle layer portion of the raw material charging layer is generated. This is because even if the heat level rises and the heat level rises, the sintering reaction is suppressed and excessive melt formation is suppressed.
【００４５】したがって、上記の粒度分布を満足するよ
うにして、原料装入層の上層部側ほど擬似粒子径が小さ
くなるような粒度偏析装入を行うことが、原料装入層の
層高方向における熱量分布を均一化する上で最も好まし
い。以上のような焼結プロセスで焼結原料を焼成するこ
とにより、ＳｉＯ2含有量が４．８重量％以下であっ
て、ＦｅＯ含有量が６．０重量％以下の焼結鉱が得ら
れ、この焼結鉱はＪＩＳ−ＲＩ：７２％以上、生産率：
１．７Ｔ／ｈ／ｍ2以上を満足することができる。Therefore, in order to satisfy the above-mentioned particle size distribution, the particle size segregation charging such that the pseudo particle size becomes smaller toward the upper layer side of the material charging layer is carried out in the layer height direction of the material charging layer. It is most preferable in order to make the heat quantity distribution in (1) uniform. By firing the sintering raw material in the above-described sintering process, a sinter having a SiO 2 content of 4.8 wt% or less and a FeO content of 6.0 wt% or less can be obtained. This sintered ore is JIS-RI: 72% or more, production rate:
It can satisfy 1.7 T / h / m 2 or more.
【００４６】また、このようなＳｉＯ2含有量：４．８
重量％以下、ＦｅＯ含有量：６．０重量％以下の焼結鉱
を、特に微粉炭多量吹込みを伴う高炉のシリコン操業に
おいて装入原料として用いることにより、以下のような
大きな利点が得られる。すなわち、高炉内において焼結
鉱を含む装入原料が還元される過程で、シャフト下部か
らボッシュ部の１０００〜１２００℃付近の温度レベル
の領域にかけて軟化溶融帯が形成されることが知られて
いるが、１０００℃付近の温度域では高炉内でも上述し
た(2)式の反応が生じ、ファイヤライト主体の低融点ス
ラグが生成し易い。この低融点スラグは、焼結鉱中のＦ
ｅＯとＳｉＯ2が反応して生成するものであるが、この
ような低融点スラグが生成すると、軟化溶融帯形成が比
較的低温度側（シャフトの上方）から始まるため、軟化
溶融帯が炉高方向での厚みを増して炉内通気性を阻害す
るという問題がある。Further, such a SiO 2 content: 4.8
The following great advantages are obtained by using a sintered ore having a FeO content of 6.0% by weight or less and a FeO content of 6.0% by weight or less as a charging raw material, especially in the silicon operation of a blast furnace involving the injection of a large amount of pulverized coal. . That is, it is known that a softening / melting zone is formed from the lower portion of the shaft to the temperature level region of about 1000 to 1200 ° C. in the Bosch portion in the process of reducing the charging raw material containing sinter in the blast furnace. However, in the temperature range around 1000 ° C., the reaction of the above formula (2) occurs even in the blast furnace, and the low melting point slag mainly composed of firelite is easily generated. This low melting point slag is the F in sinter ore.
Although eO and SiO 2 are formed by reaction, when such a low melting point slag is formed, the softening / melting zone formation starts from a relatively low temperature side (above the shaft), so There is a problem that the thickness in the direction is increased to impair the air permeability in the furnace.
【００４７】特に、微粉炭多量吹込みを伴う高炉操業で
は炉内ガス発生量が多くなるため炉内通気性の確保が極
めて重要であり、軟化溶融帯により炉内通気性が阻害さ
れると炉況が著しく悪化する可能性がある。したがっ
て、このような微粉炭多量吹込みを伴う高炉操業では、
上述したファイヤライト主体の低融点スラグの生成を極
力抑制することが不可欠である。この点、本発明の焼結
鉱ではＳｉＯ2、ＦｅＯの含有量がともに十分に低減さ
れているため、上記のようなファイヤライト主体の低融
点スラグの生成を効果的に抑制でき、これにより微粉炭
多量吹込み操業下における炉内通気性を効果的に改善す
ることができ、これにより微粉炭多量吹込み・低シリコ
ン操業を安定的に実施することができる。。Particularly, in a blast furnace operation in which a large amount of pulverized coal is blown, it is extremely important to secure the air permeability in the furnace because the gas generation amount in the furnace is large. The situation may deteriorate significantly. Therefore, in such a blast furnace operation involving a large amount of pulverized coal injection,
It is indispensable to suppress the generation of the low melting point slag mainly composed of firelite as much as possible. In this respect, since the contents of SiO 2 and FeO are both sufficiently reduced in the sintered ore of the present invention, it is possible to effectively suppress the formation of the low melting point slag mainly composed of firelite as described above, and thereby the fine powder It is possible to effectively improve the in-furnace air permeability under the operation in which a large amount of coal is blown, and thus it is possible to stably inject a large amount of pulverized coal and operate with low silicon. .
【００４８】[0048]
【実施例】図１に示したフローに従って本発明の焼結鉱
を製造した。使用した配合原料の銘柄構成を表２に示
す。また、配合原料の成分、粒度構成および固体燃料粉
である粉コークスの平均粒度を表３に示す。また、同様
の配合原料を用いて比較例となる焼結鉱も製造した。造
粒機としては、１次造粒工程ではドラムミキサー（内径
４．４ｍ、有効長さ１５ｍ）を用い、また、２次造粒工
程ではドラムミキサー（内径５．０ｍ、有効長さ１８
ｍ）または皿型造粒機（直径７．５ｍ、深さ０．５ｍ）
を用いた。また、焼結機としては有効焼結面積４００ｍ
2、装入層層厚５７０ｍｍ、ブロアー負圧１７．７ｋＰ
ａのドワイトロイド型焼結機を使用した。EXAMPLE A sintered ore according to the present invention was manufactured according to the flow shown in FIG. Table 2 shows the brand composition of the blended raw materials used. Table 3 shows the components of the blended raw materials, the particle size composition, and the average particle size of the powder coke which is the solid fuel powder. A sinter ore as a comparative example was also produced by using the same raw materials. As a granulator, a drum mixer (internal diameter 4.4 m, effective length 15 m) was used in the primary granulation process, and a drum mixer (internal diameter 5.0 m, effective length 18 m) in the secondary granulation process.
m) or a dish-type granulator (diameter 7.5 m, depth 0.5 m)
Was used. Also, as a sintering machine, the effective sintering area is 400m.
2 , charging layer layer thickness 570mm, blower negative pressure 17.7kP
The dwightroid type sintering machine of a was used.
【００４９】焼結機における原料装入装置の装入シュー
トとしては、本発明例については、図３に示すようなス
リットを有するスクリーン状シュート（ワイヤータイプ
のスクリーン状シュート）を使用し、比較例では板状の
スローピングシュートを使用した。本発明例について
は、２次造粒工程で粉コークスの全量を添加（外装）す
る操業例１と、全粉コークスのうち１次造粒工程で３０
重量％を添加（内装）し、２次造粒工程で残りの７０重
量％を添加（外装）する操業例２を実施した。一方、比
較例では１次造粒工程で粉コークスの全量を添加（内
装）する操業を行った。As the charging chute of the raw material charging device in the sintering machine, a screen-shaped chute (a wire-type screen-shaped chute) having slits as shown in FIG. Then, a plate-shaped sloping chute was used. Regarding the example of the present invention, an operation example 1 in which the entire amount of powder coke was added (exterior) in the secondary granulation step, and 30 in the primary granulation step of the total powder coke
An operation example 2 was carried out in which the weight% was added (interior) and the remaining 70 weight% was added (exterior) in the secondary granulation step. On the other hand, in the comparative example, an operation was performed in which the entire amount of powder coke was added (interior) in the primary granulation step.
【００５０】[0050]
【表２】 [Table 2]
【００５１】[0051]
【表３】 [Table 3]
【００５２】装入シュートの形式による原料装入層高さ
方向での擬似粒子の粒度分布の違いを調べるために、ス
リットを有するスクリーン状シュートを用いて原料装入
を行った本発明例と、板状の装入シュートを用いて原料
装入を行った比較例の各場合について、原料装入層から
層高方向で約１０ｃｍ毎に原料のサンプリングを行い、
層高方向各位置での平均擬似粒子径を調べた。図４はそ
の結果を示しており、本発明例のようにスリットを有す
るスクリーン状シュートを用いることにより、原料装入
層の上層部側ほど擬似粒子の平均粒径が小さい理想的な
粒度偏析装入状態が得られていることが判る。In order to investigate the difference in the particle size distribution of the pseudo particles in the height direction of the raw material charging layer depending on the type of charging chute, an example of the present invention in which the raw material was charged using a screen chute having slits, In each case of the comparative examples in which the raw material was charged using a plate-shaped charging chute, the raw material was sampled from the raw material charging layer in every 10 cm in the layer height direction,
The average pseudo particle size at each position in the bed height direction was examined. FIG. 4 shows the results, and by using a screen-shaped chute having slits as in the case of the present invention, an ideal particle size segregation apparatus in which the average particle size of pseudo particles is smaller toward the upper layer side of the raw material charging layer is shown. It can be seen that the entry state has been obtained.
【００５３】表４に本発明例および比較例の焼結操業諸
元及び成品焼結鉱の性状を示す。これによれば、本発明
例の焼結鉱はＳｉＯ2含有量が４．８重量％以下におい
てＦｅＯ含有量：６．０重量％以下、ＪＩＳ−ＲＩ：７
２％以上が得られ、しかも１．９Ｔ／ｈ／ｍ2以上の高
い生産率でありながら、比較例に比べて遜色のない強度
及び歩留りが達成されている。また、粉コークスが擬似
粒子の表層部に外装（被覆）されることより粉コークス
の燃焼性が改善された結果、比較例に較べてコークス原
単位が約６〜８ｋｇ／ｔ程度も低減している。また、表
４には示していないが、返鉱原単位についても比較例に
較べて約４０ｋｇ／ｔも減少した。Table 4 shows the specifications of the sintering operation of the present invention and comparative examples and the properties of the product sintered ore. According to this, in the sinter of the present invention example, when the SiO 2 content is 4.8% by weight or less, the FeO content: 6.0% by weight or less, JIS-RI: 7
2% or more was obtained and the production rate was as high as 1.9 T / h / m 2 or more, and the strength and yield comparable to those of Comparative Examples were achieved. In addition, as a result of improving the combustibility of the powder coke by coating (covering) the surface layer of the pseudo particles with the powder coke, the coke unit is reduced by about 6 to 8 kg / t as compared with the comparative example. There is. Further, although not shown in Table 4, the return ore unit consumption also decreased by about 40 kg / t compared to the comparative example.
【００５４】[0054]
【表４】 [Table 4]
【００５５】[0055]
【発明の効果】以上述べたように本発明の焼結鉱の製造
方法によれば、低ＳｉＯ ２ 含有量で且つ高被還元性、高
生産率の焼結鉱を、良好な成品歩留まりで安定して製造
することができる。As described above, the production of the sintered ore of the present invention
According to the method, a sinter having a low SiO 2 content, a high reducibility, and a high production rate can be stably produced with a good product yield.
【図１】本発明の焼結鉱の製造フローの一例を示す説明
図FIG. 1 is an explanatory view showing an example of a production flow of a sinter according to the present invention.
【図２】擬似粒子径と擬似粒子の単位重量当たりの固体
燃料粉濃度との関係を示すグラフFIG. 2 is a graph showing the relationship between the pseudo particle size and the solid fuel powder concentration per unit weight of the pseudo particle.
【図３】本発明の焼結鉱の製造で用いられる原料装入装
置のスクリーン状シュートおよびこれによる焼結機パレ
ット上への原料装入状況を示す説明図FIG. 3 is an explanatory view showing a screen chute of a raw material charging device used in the production of the sintered ore of the present invention and a raw material charging state on a sinter machine pallet by the screen chute.
【図４】図３に示すスクリーン状シュートと板状の装入
シュートをそれぞれ用いて焼結機パレット上への原料装
入を行った場合について、原料装入層高さ方向での擬似
粒子粒度分布を示すグラフFIG. 4 shows the pseudo particle size in the height direction of the raw material charging layer when the raw material is charged on the sintering machine pallet using the screen chute and the plate charging chute shown in FIG. 3, respectively. Graph showing distribution
１…Ｂ粉、２…固体燃料粉、３…返鉱、４…媒溶材、５
…１次ドラムミキサー（または皿型造粒機）、６…２次
ドラムミキサー（または皿型造粒機）、７…焼結機、８
…スクリーン状シュート、９…原料供給部、１０…スリ
ット、１１…スクリーン構成部材、１２…焼結機パレッ
ト1 ... B powder, 2 ... solid fuel powder, 3 ... return ore, 4 ... solvent, 5
... primary drum mixer (or dish type granulator), 6 ... secondary drum mixer (or dish type granulator), 7 ... sintering machine, 8
... screen-shaped chute, 9 ... raw material supply section, 10 ... slit, 11 ... screen component, 12 ... sintering machine pallet
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭61−281829（ＪＰ，Ａ) 特開 平２−254125（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C22B 1/00 - 61/00 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-281829 (JP, A) JP-A-2-254125 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) C22B 1/00-61/00
Claims (4)
が３０重量％未満であって、成品焼結鉱のＳｉＯ２含有
量が４．８重量％以下になるように調整された配合原料
をドラムミキサーまたは皿型造粒機で１次造粒する工程
と、該工程で得られた１次造粒物に固体燃料粉の全量を
加えてドラムミキサーまたは皿型造粒機で２次造粒し、
固体燃料粉で被覆された擬似粒子を得る工程と、該工程
で得られた擬似粒子を焼結機パレット上に、擬似粒子の
粒度が原料装入層高さ方向で下層側＞上層側となるよう
な粒度分布を有する状態に装入する工程と、該原料装入
層を焼結する工程とを有することを特徴とするＳｉＯ２
含有量が低い焼結鉱の製造方法。 1. A blended raw material in which the proportion of particles having a particle diameter of 0.125 mm or less is less than 30% by weight, and the SiO 2 content of the product sinter is adjusted to 4.8% by weight or less. Primary granulation with a drum mixer or a dish granulator, and adding the total amount of solid fuel powder to the primary granulation product obtained in the step to carry out a secondary granulation with a drum mixer or a dish granulator. And then
The step of obtaining the pseudo particles coated with the solid fuel powder, and the pseudo particles obtained in the step are placed on a sinter machine pallet,
The particle size should be such that the lower layer side> the upper layer side in the height direction of the raw material charging layer.
SiO 2 characterized by having a step of charging into a state having a different particle size distribution and a step of sintering the raw material charging layer.
A method for producing a sinter having a low content.
が３０重量％未満であって、成品焼結鉱のＳｉＯ２含有
量が４．８重量％以下になるように調整された配合原料
を、全固体燃料粉のうちの３０重量％未満の固体燃料粉
とともにドラムミキサーまたは皿型造粒機で１次造粒す
る工程と、該工程で得られた１次造粒物に固体燃料粉の
残量分を加えてドラムミキサーまたは皿型造粒機で２次
造粒し、固体燃料粉で被覆された擬似粒子を得る工程
と、該工程で得られた擬似粒子を焼結機パレット上に、
擬似粒子の粒度が原料装入層高さ方向で下層側＞上層側
となるような粒度分布を有する状態に装入する工程と、
該原料装入層を焼結する工程とを有することを特徴とす
るＳｉＯ２含有量が低い焼結鉱の製造方法。 2. A blended raw material in which the proportion of particles having a particle size of 0.125 mm or less is less than 30% by weight, and the SiO 2 content of the product sinter is adjusted to 4.8% by weight or less. Primary granulation with a drum mixer or a dish type granulator together with solid fuel powder of less than 30% by weight of the total solid fuel powder, and solid fuel powder in the primary granulated product obtained in the step. The secondary step of adding the remaining amount of the above to secondary granulation with a drum mixer or a dish type granulator to obtain pseudo particles coated with solid fuel powder, and the pseudo particles obtained in the step are placed on a sinter machine pallet. To
The particle size of the pseudo particles is the lower layer side in the height direction of the raw material charging layer> the upper layer side
Charging into a state having a particle size distribution such that
And a step of sintering the raw material charging layer, the method for producing a sintered ore having a low SiO 2 content.
料装入装置の原料供給部の下方に下向き傾斜状に設けら
れた原料装入用シュートであって、焼結機パレット幅方
向と略平行なスリットをシュート上下方向で並列的に複
数形成し、該スリットの幅をシュート上部側ほど狭めた
構造を有するスクリーン状シュートを介して、焼結機パ
レット上に装入することにより、擬似粒子の粒度が原料
装入層高さ方向で下層側＞上層側となるような粒度分布
を有する状態とすることを特徴とする請求項１または２
に記載のＳｉＯ２含有量が低い焼結鉱の製造方法。 3. A raw material charging chute in which the pseudo particles obtained in the secondary granulation step are provided in a downwardly sloping shape below a raw material supplying section of a raw material charging device, and the sintering machine pallet width By forming a plurality of slits parallel to each other in the vertical direction of the chute in parallel with each other, and inserting the slits on the sinter machine pallet through a screen-shaped chute having a structure in which the width of the slit is narrowed toward the upper part of the chute. , The size of pseudo particles is the raw material
Particle size distribution such that the lower layer side> the upper layer side in the height direction of the charging layer
3. The method according to claim 1 or 2 , characterized in that
The method for producing a sinter having a low SiO 2 content according to 1.
り４４ｋｇ以下であることを特徴とする請求項１、２ま
たは３に記載のＳｉＯ２含有量が低い焼結鉱の製造方
法。 4. The method of claim total amount of the solid fuel powder is equal to or less than-products sintered ore 1t per 44 kg 1, 2 or
Or 3. A method for producing a sintered ore having a low SiO 2 content.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07315998A JP3531464B2 (en) | 1998-03-06 | 1998-03-06 | Method for producing sintered ore with low SiO2 content |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07315998A JP3531464B2 (en) | 1998-03-06 | 1998-03-06 | Method for producing sintered ore with low SiO2 content |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11256248A JPH11256248A (en) | 1999-09-21 |
| JP3531464B2 true JP3531464B2 (en) | 2004-05-31 |
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ID=13510126
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07315998A Expired - Fee Related JP3531464B2 (en) | 1998-03-06 | 1998-03-06 | Method for producing sintered ore with low SiO2 content |
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| Country | Link |
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| JP (1) | JP3531464B2 (en) |
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| JP5544784B2 (en) * | 2009-08-17 | 2014-07-09 | Ｊｆｅスチール株式会社 | Sintering machine |
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