JP2011127197A - Method for operating blast furnace - Google Patents

Method for operating blast furnace Download PDF

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JP2011127197A
JP2011127197A JP2009287955A JP2009287955A JP2011127197A JP 2011127197 A JP2011127197 A JP 2011127197A JP 2009287955 A JP2009287955 A JP 2009287955A JP 2009287955 A JP2009287955 A JP 2009287955A JP 2011127197 A JP2011127197 A JP 2011127197A
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blast furnace
mgo
pellet
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JP5400600B2 (en
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Mutsumi Tanaka
睦 田中
Yoshiyuki Matsui
良行 松井
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Kobe Steel Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for operating a blast furnace with which in the blast furnace operation using sintered ore together with pellet as the iron-ore raw material, in the case of changing the pellet-blending ratio, the molten iron S can surely be kept to the low level. <P>SOLUTION: In the method for operating the blast furnace, in which the iron-ore raw material composed of the pellet, the sintered ore and lump ore, and coke are alternately charged so as to forma layers; in the case of raising the blending ratio of the pellet in the iron-ore raw material (in the following, [pellet blending ratio]), the charging quantity of MgO into the blast furnace (in the following, [charged MgO quantity into the blast furnace]) is increased, and in the case of lowering the pellet blending ratio, the charged MgO quantity into the blast furnace is reduced. To 1 mass% of the changing quantity of the pellet blending ratio, it is desirable to change the charged MgO quantity into the blast furnace by 0.2-0.8 kg per 1 ton of the molten iron. It is more desirable to adjust the increase and the decrease of the changed MgO quantity into the blast furnace in the range of &ge;1 mass% of MgO content in the pellet. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

本発明は、ペレット、焼結鉱および塊鉱石からなる鉄鉱石原料とコークスを交互に層状に装入する高炉操業方法に関し、特にペレット多配合条件下においても溶銑中のS含有量を低位に維持しうる高炉操業方法に関する。   The present invention relates to a method for operating a blast furnace in which iron ore raw materials consisting of pellets, sintered ore and lump ore and coke are alternately charged in layers, and in particular, the S content in the hot metal is maintained at a low level even under conditions of multiple pellets It relates to a possible blast furnace operation method.

高炉操業に用いられる鉄鉱石原料は、需給バランス等によって高炉に拠らずほぼ一定の塊鉱石配合率(鉄鉱石原料中の10〜30質量%程度)となっており、残りの配合率は焼成鉱である、焼結鉱とペレットで按分されている。   The iron ore raw material used for blast furnace operation has almost constant lump ore blending ratio (about 10-30% by mass in iron ore raw material) regardless of the blast furnace due to supply and demand balance, etc., and the remaining blending ratio is calcined It is divided by the ore, sintered ore and pellets.

本出願人の加古川製鉄所に設置された高炉では、ペレット配合率を30〜40質量%程度まで高めたペレット多配合操業を行っているが、焼結鉱に置換してペレットの配合割合を上昇させると、溶銑中のS含有量(以下、「溶銑S」と略称することあり。)が上昇する傾向が見られ、下工程の製鋼工程における脱硫コストが上昇する問題があった。   In the blast furnace installed at the applicant's Kakogawa Works, the pellet blending ratio is increased to about 30 to 40% by mass, but the blending ratio of pellets is increased by replacing with sintered ore. As a result, there is a tendency that the S content in the hot metal (hereinafter sometimes abbreviated as “hot metal S”) tends to increase, and the desulfurization cost in the lower steelmaking process increases.

ここで、高炉内における溶銑の脱硫を促進するため、種々の提案がなされており、例えば、特許文献1では、鉄鉱石とコークスを層状に装入する高炉操業において、高炉内でMgO含有物質とCが共存状態で存在するよう、該MgO含有物質の周囲にコークスを、または装入するコークスをMgO含有コークスと置換して、またはMgOを含有した含炭ペレットを高炉内へ装入する高炉内における溶銑Sの低減方法が開示されている。   Here, various proposals have been made to promote the desulfurization of hot metal in the blast furnace. For example, in Patent Document 1, in the blast furnace operation in which iron ore and coke are charged in layers, In the blast furnace in which coke is present around the MgO-containing material, or the coke to be charged is replaced with MgO-containing coke, or the carbon-containing pellets containing MgO are charged into the blast furnace so that C exists in a coexisting state. A method for reducing the hot metal S is disclosed.

このように、高炉内にMgO含有物質を装入することにより、一定の脱硫効果が得られることが知られているものの、MgO含有物質の周囲にコークスを装入するために、MgO含有物質として最も一般的なドロマイト(CaCO・MgCO)を用いると、ドロマイトが熱分解して発生したCOガスによりコークスがソリューションロス反応して劣化しやすく、また、MgO含有コークスやMgOを含有した含炭ペレットを製造することも工業規模では実用的でなく、いまだ実用化に至っていない。 Thus, although it is known that a certain desulfurization effect can be obtained by charging the MgO-containing material into the blast furnace, in order to charge coke around the MgO-containing material, When the most common dolomite (CaCO 3 · MgCO 3 ) is used, coke tends to deteriorate due to solution loss reaction due to CO 2 gas generated by thermal decomposition of dolomite, and also contains MgO-containing coke and MgO-containing coke. Production of charcoal pellets is also not practical on an industrial scale and has not yet been put into practical use.

一方、特許文献2には、高炉の鉄鉱石原料として用いられるペレットとして、CaO/SiO質量比およびMgO/SiO質量比と、粒径分布を規定した高炉用自溶性ペレットが開示されている。このような自溶性ペレットを用いることで、ペレットを多配合する高炉操業において、高炉内におけるシャフト部の通気性を改善することができるようになった。 On the other hand, Patent Document 2 discloses a self-fluxing pellet for a blast furnace in which a CaO / SiO 2 mass ratio and a MgO / SiO 2 mass ratio and a particle size distribution are defined as pellets used as an iron ore raw material for a blast furnace. . By using such self-fluxing pellets, the air permeability of the shaft portion in the blast furnace can be improved in blast furnace operation in which many pellets are blended.

また、特許文献3には、高炉の鉄鉱石原料として用いられるペレットとして、鉄品位%TFeに応じた最適なCaO/SiO質量比とMgO/SiO質量比の組み合わせの範囲を規定した高炉用自溶性ペレットが開示されている。高炉用鉄原料として、このような自溶性ペレットを焼結鉱と併用して用いることで、高炉内における融着帯の通気性を改善することができるようになった。 In addition, Patent Document 3 discloses a pellet for use as an iron ore raw material for a blast furnace, in which an optimum combination range of CaO / SiO 2 mass ratio and MgO / SiO 2 mass ratio according to iron grade% TFe is defined. Self-dissolving pellets are disclosed. By using such self-fluxing pellets in combination with sintered ore as an iron raw material for a blast furnace, the air permeability of the cohesive zone in the blast furnace can be improved.

上記特許文献2、3に記載の発明のように、鉄鉱石原料であるペレットへのMgO添加量の調整により、ペレット自身の高温性状を改良して、焼結鉱と同等の高温性状に近づけることで、高炉内の通気性改善に一定の効果があることが知られているものの、このペレットへのMgO添加量の変化が高炉内における脱硫効果にどのように影響するかについては定量的な検討がなされておらず、明確でなかった。   As in the inventions described in Patent Documents 2 and 3 above, by adjusting the amount of MgO added to the pellets that are iron ore raw materials, the high temperature properties of the pellets themselves are improved to approach the high temperature properties equivalent to those of sintered ore. Although it is known that there is a certain effect in improving the air permeability in the blast furnace, a quantitative study is conducted on how the change in the amount of MgO added to the pellets affects the desulfurization effect in the blast furnace. Was not made and was not clear.

したがって、焼結鉱をペレットに置換することにより生じる溶銑S上昇の問題に対しては、確実に対応しうる方策はいまだ確立していないのが現状であった。   Accordingly, the present situation is that a measure that can reliably cope with the problem of the hot metal S increase caused by replacing the sintered ore with pellets has not yet been established.

特開2004−244681号公報JP 2004-244681 A 特開2008−280556号公報JP 2008-280556 A 特開2009−149942号公報JP 2009-149492 A

そこで、本発明は、鉄鉱石原料として焼結鉱とペレットを併用する高炉操業において、ペレット配合率が変化しても、確実に溶銑Sを低位に維持しうる高炉操業方法を提供することを目的とする。   Then, this invention aims at providing the blast furnace operation method which can maintain hot metal S reliably in the low level even if a pellet compounding rate changes in the blast furnace operation which uses a sintered ore and a pellet together as an iron ore raw material. And

上記課題を解決するため、本発明者らは、まず、焼結鉱に置換してペレットの配合割合を上昇させると、溶銑Sが上昇する傾向が見られる原因について種々検討を行った結果、以下のような推定メカニズムによるとの推論に到達した。   In order to solve the above-mentioned problems, the present inventors first conducted various studies on the cause of the tendency of the hot metal S to rise when the ratio of pellets was increased by replacing with sintered ore. We arrived at the inference according to the presumed mechanism.

すなわち、通常、塊鉱石はスラグ成分含有量(脈石量)が5〜10質量%程度の低スラグ成分含有量のものが使用され、焼結鉱は、その強度を確保するため、スラグ成分含有量が15〜25質量%程度の高スラグ成分含有量のものが使用されるのに対し、ペレットは、前記両者の中間の、スラグ成分含有量が10〜20質量%程度の中スラグ成分含有量のものが使用される。このため、焼結鉱に置換してペレットの配合割合を高くすると、高炉スラグの発生量が減少し、スラグ比[kg/t−溶銑]が低下する。   That is, normally, a lump ore having a low slag component content with a slag component content (amount of gangue) of about 5 to 10% by mass is used, and the sintered ore contains a slag component in order to ensure its strength. Whereas the amount of high slag component content is about 15 to 25% by mass, the pellet is intermediate between the two, and the content of medium slag component is about 10 to 20% by mass. Is used. For this reason, if it replaces with a sintered ore and raises the mixture ratio of a pellet, the generation amount of blast furnace slag will reduce and slag ratio [kg / t-hot metal] will fall.

ところで、高炉への装入原料中のS分の大半はコークス中のSであり、このSは、レースウェイ近傍の高温場で発生した高温ガス中ではS含有ガス成分となるが、このS含有ガス成分は炉内を上昇中に鉄鉱石類に吸収され、その後炉床でのスラグ−メタル反応によってスラグ側に多く分配されることによって高炉内において溶銑からの脱硫が実現されている。   By the way, most of the S content in the raw material charged to the blast furnace is S in coke, and this S becomes an S-containing gas component in the high-temperature gas generated in the high-temperature field near the raceway. Gas components are absorbed by iron ores while rising in the furnace, and then are distributed to the slag side by a slag-metal reaction in the hearth, thereby achieving desulfurization from hot metal in the blast furnace.

このため、上記のように、焼結鉱に置換してペレットの配合割合を高くすると、スラグ比が低下し、その結果、炉床においてメタル(溶銑)量に対するスラグ量が減少し、スラグ側に分配されるSの絶対量が減少するので、溶銑中のS含有量が上昇すると考えられる。   For this reason, as described above, when the ratio of pellets is increased by replacing with sintered ore, the slag ratio decreases, and as a result, the amount of slag with respect to the amount of metal (hot metal) decreases in the hearth, and on the slag side. Since the absolute amount of distributed S decreases, it is considered that the S content in the hot metal increases.

上記推論を検証するため、鉄鉱石原料として焼結鉱とペレットを併用している加古川製鉄所第3高炉(内容積:4500m)において、ペレット配合率を30〜39質量%の間で変化させた期間の操業データを解析して、ペレット配合率とスラグ比との相関関係、および、スラグ比と脱硫率との相関関係を調査した。 In order to verify the above reasoning, in the Kakogawa Works No. 3 blast furnace (internal volume: 4500 m 3 ), which uses both sintered ore and pellets as iron ore raw materials, the pellet mixing ratio was changed between 30 and 39% by mass. We analyzed the operation data during the period, and investigated the correlation between the pellet content and the slag ratio, and the correlation between the slag ratio and the desulfurization rate.

ここに、ペレット配合率は、ペレット、焼結鉱および塊鉱石からなる鉄鉱石原料中のペレットの配合割合(単位:質量%)であり、スラグ比は、溶銑1トン当たりに発生するスラグ量(単位:kg/t−溶銑)であり、脱硫率は、〔溶銑中のS量〕/〔高炉への装入全S量〕×100(単位:%)である。   Here, the pellet blending ratio is the blending ratio (unit: mass%) of pellets in the iron ore raw material consisting of pellets, sintered ore and lump ore, and the slag ratio is the amount of slag generated per ton of hot metal ( The unit is kg / t-molten iron), and the desulfurization rate is [S amount in molten iron] / [total amount of S charged to blast furnace] × 100 (unit:%).

調査結果を図1および図2に示す。   The survey results are shown in FIG. 1 and FIG.

図1に見られるとおり、ペレット配合率の上昇とともにスラグ比が低下しており、また、図2に見られるとおり、スラグ比の低下に伴って脱硫率が低下することが確認でき、上記推論が裏付けられた。   As can be seen from FIG. 1, the slag ratio decreases as the pellet content increases, and as can be seen from FIG. 2, it can be confirmed that the desulfurization rate decreases as the slag ratio decreases. It was supported.

そこで、次に、高炉装入MgO量と脱硫比との相関関係を調査した。   Then, next, the correlation between the amount of MgO charged in the blast furnace and the desulfurization ratio was investigated.

調査結果を図3に示す。同図に見られるとおり、高炉装入MgO量の増加とともに脱硫率が上昇することがわかった。   The survey results are shown in FIG. As seen in the figure, it was found that the desulfurization rate increased as the amount of MgO charged in the blast furnace increased.

図1〜図3の各図中に示した相関直線の傾きより、ペレット配合率を1質量%上昇させるとスラグ比が1.72kg/t−溶銑減少し、スラグ比が1kg/t−溶銑減少すると脱硫率が0.029%低下し、一方、高炉装入MgO量を1kg/t−溶銑増加すると脱硫率が0.179%上昇することがわかる。このことから、ペレット配合率を1質量%上昇させたことによるスラグ比の減少に伴う脱硫率の低下分を補填して脱硫率を元のレベルに維持するのに必要な高炉装入MgO量は、1.72×0.029/0.179=0.279kg/t−溶銑となる。   From the slope of the correlation line shown in each of FIGS. 1 to 3, when the pellet blending ratio is increased by 1 mass%, the slag ratio is reduced by 1.72 kg / t-hot metal and the slag ratio is reduced by 1 kg / t-hot metal. Then, the desulfurization rate decreases by 0.029%. On the other hand, when the amount of MgO charged in the blast furnace is increased by 1 kg / t-molten iron, it can be seen that the desulfurization rate increases by 0.179%. From this, the amount of MgO charged in the blast furnace required to make up for the decrease in the desulfurization rate due to the decrease in the slag ratio due to the increase in the pellet content by 1% by mass and maintain the desulfurization rate at the original level is 1.72 × 0.029 / 0.179 = 0.279 kg / t-molten iron.

上記知見に基づき、焼結鉱に置換してペレットの配合割合を上昇させる際には、スラグ比の低下に伴う脱硫率の低下分を補填する分だけ高炉装入MgO量を増加すればよいと考え、以下の発明を完成するに至った。   Based on the above findings, when increasing the blending ratio of pellets by replacing with sintered ore, the amount of MgO charged in the blast furnace should be increased by an amount that compensates for the decrease in the desulfurization rate accompanying the decrease in the slag ratio. As a result, the following invention has been completed.

請求項1に記載の発明は、ペレット、焼結鉱および塊鉱石からなる鉄鉱石原料とコークスを交互に層状に装入する高炉操業方法において、前記鉄鉱石原料中のペレットの配合割合(以下、「ペレット配合率」という。)を上昇させる場合には、高炉へのMgOの装入量(以下、「高炉装入MgO量」という。)を増加させ、前記ペレット配合率を低下させる場合には、前記高炉装入MgO量を減少させることを特徴とする高炉操業方法である。   The invention according to claim 1 is a blast furnace operation method in which iron ore raw material and coke composed of pellets, sintered ore and lump ore are alternately charged in layers, and the mixing ratio of pellets in the iron ore raw material (hereinafter, When increasing the amount of MgO charged to the blast furnace (hereinafter referred to as “the amount of MgO charged to the blast furnace”) when increasing the pellet content, The blast furnace operating method is characterized in that the amount of MgO charged in the blast furnace is reduced.

請求項2に記載の発明は、前記ペレット配合率の変更量1質量%に対して、前記高炉装入MgO量を溶銑1トン当たり0.2〜0.8kg変化させる請求項1に記載の高炉操業方法である。   The invention according to claim 2 is the blast furnace according to claim 1, wherein the amount of MgO charged in the blast furnace is changed by 0.2 to 0.8 kg per ton of hot metal with respect to the change amount of the pellet mixing ratio of 1% by mass. Operation method.

請求項3に記載の発明は、前記高炉装入MgO量の増減を、前記ペレットのMgO含有量を1質量%以上の範囲で調整することにより行う請求項1または2に記載の高炉操業方法である。   The invention described in claim 3 is the blast furnace operating method according to claim 1 or 2, wherein the increase or decrease of the MgO content of the blast furnace is performed by adjusting the MgO content of the pellets in a range of 1 mass% or more. is there.

本発明によれば、ペレット配合率に応じて高炉装入MgO量を調整することで、脱硫率を確実かつ高位に維持することが可能となり、鉄鉱石原料として焼結鉱とペレットを併用する高炉操業において、ペレット配合率が変化しても、安定して溶銑Sを低位に維持しうる高炉操業方法を提供することが実現できるようになった。   According to the present invention, by adjusting the amount of MgO charged in the blast furnace according to the pellet mixing ratio, the desulfurization rate can be reliably maintained at a high level, and a blast furnace that uses sintered ore and pellets together as an iron ore raw material In operation, it has become possible to provide a blast furnace operation method that can stably maintain the molten iron S at a low level even if the pellet content changes.

ペレット配合率とスラグ比との関係を示すグラフ図である。It is a graph which shows the relationship between a pellet compounding rate and slag ratio. スラグ比と脱硫率との関係を示すグラフ図である。It is a graph which shows the relationship between a slag ratio and a desulfurization rate. 高炉装入MgO量と脱硫率との関係を示すグラフ図である。It is a graph which shows the relationship between the amount of blast furnace charging MgO, and a desulfurization rate.

以下、本発明の実施の形態について、さらに詳細に説明する。   Hereinafter, embodiments of the present invention will be described in more detail.

〔実施形態〕
本発明は、ペレット、焼結鉱および塊鉱石からなる鉄鉱石原料とコークスを交互に層状に装入する高炉操業方法において、ペレット配合率を上昇させる場合には、高炉装入MgO量を増加させ、ペレット配合率を低下させる場合には、高炉装入MgO量を減少させることを特徴とする。
Embodiment
In the blast furnace operation method in which iron ore raw materials and coke composed of pellets, sintered ore and lump ore are alternately charged in layers, the present invention increases the amount of MgO charged in the blast furnace when increasing the pellet content. When lowering the pellet blending ratio, the amount of MgO charged in the blast furnace is reduced.

ここに、高炉装入MgO量の調整は、例えば、鉄鉱石原料に塊状のMgO含有物質を混合し、この混合物を炉頂から装入するに当たり、該塊状のMgO含有物質の量を変更することにより容易に行うことができる。MgO含有物質としては、ドロマイト、蛇紋岩、マグネサイト、マグネシアクリンカ等を用いることができる。   Here, the amount of MgO-containing material in the blast furnace is adjusted by, for example, mixing a massive MgO-containing material into the iron ore raw material, and changing the amount of the massive MgO-containing material when charging the mixture from the top of the furnace. Can be easily performed. As the MgO-containing substance, dolomite, serpentine, magnesite, magnesia clinker and the like can be used.

また、ペレット配合率の変更量1質量%に対して、高炉装入MgO量を溶銑1トン当たり0.2〜0.8kg変化させるのが好ましい。0.2kg/t−溶銑未満では、脱硫率の低下が十分に阻止できず、一方0.8kg/t−溶銑を超えると脱硫率の上昇が頭打ちとなり、余分なMgO含有物質の装入により溶銑の製造コストが増加するためである。高炉装入MgO量のより好ましい上限は溶銑1トン当たり0.6kgである。なお、上述の図1〜図3の解析結果より、ペレット配合率の変更量1質量%に対して、高炉装入MgO量を溶銑1トン当たり0.279kg変化させるのが最も推奨される。   Further, it is preferable to change the amount of MgO charged to the blast furnace by 0.2 to 0.8 kg per ton of hot metal with respect to the change amount of the pellet mixing ratio of 1% by mass. If the amount is less than 0.2 kg / t-hot metal, the decrease in the desulfurization rate cannot be sufficiently prevented. This is because the manufacturing cost increases. A more preferable upper limit of the amount of MgO charged in the blast furnace is 0.6 kg per ton of hot metal. From the analysis results of FIGS. 1 to 3 described above, it is most recommended to change the amount of MgO charged to the blast furnace by 0.279 kg per ton of hot metal with respect to the change amount of the pellet mixing ratio of 1 mass%.

また、高炉装入MgO量の増減を、ペレットのMgO含有量を1質量%以上の範囲で調整することが好ましい。以下に好ましい理由を述べる。   Moreover, it is preferable to adjust the increase / decrease in the amount of MgO charged in the blast furnace in the range of 1% by mass or more of the MgO content of the pellets. The reason why it is preferable will be described below.

上記で例示したように、高炉装入MgO量の調整は、鉄鉱石原料に塊状のMgO含有物質を混合し、この混合物を炉頂から装入するに当たり、該塊状のMgO含有物質の量を変更することで行うことができるが、この手段に代えて、鉄鉱石原料を構成する焼成鉱である、焼結鉱および/またはペレットとして、予めMgO含有物質を添加して製造したものを装入するに当たり、それらのMgO含有量を変更することで行うことができる。   As exemplified above, the amount of MgO-containing material in the blast furnace is adjusted by mixing the massive MgO-containing material with the iron ore raw material and changing the amount of the massive MgO-containing material when charging the mixture from the top of the furnace. However, instead of this means, a sintered ore and / or pellet which is a calcined ore constituting an iron ore raw material is charged in advance with an MgO-containing material added thereto. In this case, the MgO content can be changed.

ここで、一般的に、焼結鉱はペレットよりも軟化溶融温度が高く、また、焼結鉱やペレットのMgO含有量を高めると、焼結鉱やペレット中のスラグ成分の融点が高まり、焼結鉱やペレットの軟化溶融温度が上昇することが知られている。   Here, generally, sintered ore has a softening and melting temperature higher than that of pellets, and when the MgO content of sintered ore and pellets is increased, the melting point of the slag component in the sintered ore and pellets increases, It is known that the softening and melting temperature of ores and pellets increases.

このため、焼結鉱のMgO含有量を増加させると、焼結鉱の軟化溶融温度がさらに上昇してペレットの軟化溶融温度との差が開き、高炉内における融着帯の幅が拡大する方向に作用するので、高炉内の通気性が阻害されるおそれがある。   For this reason, when the MgO content of the sinter is increased, the softening and melting temperature of the sinter is further increased, and the difference from the softening and melting temperature of the pellets is increased, and the width of the fusion zone in the blast furnace is increased. Therefore, the air permeability in the blast furnace may be hindered.

これに対し、ペレットのMgO含有量を増加させると、ペレットの軟化溶融温度が上昇して焼結鉱の軟化溶融温度に近づき、高炉内における融着帯の幅が縮小する方向に作用するので、高炉内の通気性が改善されることが期待される。   On the other hand, when the MgO content of the pellet is increased, the softening and melting temperature of the pellet rises and approaches the softening and melting temperature of the sintered ore, so that the width of the fusion zone in the blast furnace is reduced, It is expected that the air permeability in the blast furnace will be improved.

したがって、焼結鉱のMgO含有量を調整(増減)するよりも、ペレットのMgO含有量を調整(増減)する方がより推奨される。   Therefore, it is more recommended to adjust (increase / decrease) the MgO content of the pellet than to adjust (increase / decrease) the MgO content of the sintered ore.

また、ペレットのMgO含有量を調整(増減)する場合、軟化溶融性状の改善効果を発揮させるため、MgO含有量が1質量%以上の範囲で調整するのが望ましい(例えば、西田礼次郎ら,「ペレットの改質と高炉使用」,R&D神戸製鋼技報,第34巻,第4号,1984年,p.28−35、特に第7,9,11図参照)。   Further, when adjusting (increasing / decreasing) the MgO content of the pellets, it is desirable to adjust the MgO content within a range of 1% by mass or more in order to exert an effect of improving the softening and melting properties (for example, Reijiro Nishida et al., “ “Reforming pellets and using blast furnace”, R & D Kobe Steel Engineering Reports, Vol. 34, No. 4, 1984, p.28-35, especially see FIGS. 7, 9, and 11).

よって、高炉装入MgO量の増減を、ペレットのMgO含有量を1質量%以上の範囲で調整することが好ましい。   Therefore, it is preferable to adjust the increase / decrease in the amount of MgO charged in the blast furnace in the range of 1% by mass or more of the MgO content of the pellets.

本発明の適用性を確証するため、上記の加古川製鉄所第3高炉(内容積:4500m)にて、本発明の適用による脱硫率の変化を調査した。 In order to confirm the applicability of the present invention, changes in the desulfurization rate due to the application of the present invention were investigated in the Kakogawa Works No. 3 blast furnace (internal volume: 4500 m 3 ).

ペレット配合率を30%から31%へと1%増配するにあたり、ペレットのMgO含有量のみを1質量%以上の範囲で増加させて、高炉装入MgO量を溶銑1t当たり約0.5kg増加させた。   In increasing the pellet content from 30% to 31% by 1%, only the MgO content of the pellet is increased in the range of 1% by mass or more, and the amount of MgO charged in the blast furnace is increased by about 0.5 kg per ton of hot metal. It was.

その結果、ペレット配合率が30%の期間では、脱硫率は平均92.2%であったものが、ペレット配合率を31%に増配した後の期間では、脱硫率は平均93.3%へと上昇し、本発明の適用により、ペレット増配による高炉スラグ比の低下にも関わらず、却って脱硫率が改善されることを確認した。   As a result, the desulfurization rate averaged 92.2% during the period when the pellet blending rate was 30%, but the desulfurization rate reached 93.3% during the period after the pellet blending rate was increased to 31%. It was confirmed that the application of the present invention improved the desulfurization rate in spite of the decrease in the blast furnace slag ratio due to the increased pellet distribution.

Claims (3)

ペレット、焼結鉱および塊鉱石からなる鉄鉱石原料とコークスを交互に層状に装入する高炉操業方法において、前記鉄鉱石原料中のペレットの配合割合(以下、「ペレット配合率」という。)を上昇させる場合には、高炉へのMgOの装入量(以下、「高炉装入MgO量」という。)を増加させ、前記ペレット配合率を低下させる場合には、前記高炉装入MgO量を減少させることを特徴とする高炉操業方法。   In the blast furnace operation method in which iron ore raw materials and coke composed of pellets, sintered ore and lump ore are alternately charged in layers, the mixing ratio of pellets in the iron ore raw materials (hereinafter referred to as “pellet mixing ratio”). When increasing the amount of MgO charged to the blast furnace (hereinafter referred to as “the amount of MgO charged to the blast furnace”), and decreasing the pellet mixing rate, the amount of MgO charged to the blast furnace is decreased. A method of operating a blast furnace, characterized in that 前記ペレット配合率の変更量1質量%に対して、前記高炉装入MgO量を溶銑1トン当たり0.2〜0.8kg変化させる請求項1に記載の高炉操業方法。   The blast furnace operating method according to claim 1, wherein the amount of MgO charged in the blast furnace is changed by 0.2 to 0.8 kg per ton of hot metal with respect to the change amount of 1% by mass of the pellet mixture ratio. 前記高炉装入MgO量の増減を、前記ペレットのMgO含有量を1質量%以上の範囲で調整することにより行う請求項1または2に記載の高炉操業方法。   The blast furnace operating method according to claim 1 or 2, wherein the increase or decrease of the amount of MgO charged in the blast furnace is performed by adjusting the MgO content of the pellets within a range of 1 mass% or more.
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JPH1143710A (en) * 1997-07-23 1999-02-16 Nippon Steel Corp Operation of blast furnace when injecting a large quantity of pulverized fine coal
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JPS60141810A (en) * 1983-12-28 1985-07-26 Kobe Steel Ltd Method for controlling operation of blast furnace using iron ore pellet
JPS61261408A (en) * 1985-05-15 1986-11-19 Sumitomo Metal Ind Ltd Operating method for blast furnace
JPS61261407A (en) * 1985-05-16 1986-11-19 Kawasaki Steel Corp Operating method for blast furnace
JPH1143710A (en) * 1997-07-23 1999-02-16 Nippon Steel Corp Operation of blast furnace when injecting a large quantity of pulverized fine coal
JP2008240109A (en) * 2007-03-28 2008-10-09 Sumitomo Metal Ind Ltd Method for operating blast furnace

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021152213A (en) * 2020-03-19 2021-09-30 Jfeスチール株式会社 Blast furnace operation method
JP7244805B2 (en) 2020-03-19 2023-03-23 Jfeスチール株式会社 Blast furnace operation method

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