JP2013136799A - Method for producing high-carbon molten iron using iron scrap - Google Patents

Method for producing high-carbon molten iron using iron scrap Download PDF

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JP2013136799A
JP2013136799A JP2011287095A JP2011287095A JP2013136799A JP 2013136799 A JP2013136799 A JP 2013136799A JP 2011287095 A JP2011287095 A JP 2011287095A JP 2011287095 A JP2011287095 A JP 2011287095A JP 2013136799 A JP2013136799 A JP 2013136799A
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iron
carbon
scrap
molten iron
biomass
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JP5942425B2 (en
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Sumihito Ozawa
純仁 小澤
Eiju Matsuno
英寿 松野
Hidekazu Tsuruta
秀和 鶴田
Yozo Iwaki
陽三 岩城
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JFE Steel Corp
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Abstract

PROBLEM TO BE SOLVED: To reduce the amount of production of greenhouse gas by effectively using carbonaceous materials originating from biomass which is carbon-neutral as a heat source and a recarburizer in place of carbonaceous materials originating from fossil fuel such as coke and coal, etc., when producing high-carbon molten iron by using iron scrap.SOLUTION: In the method for producing high-carbon molten iron, iron scrap 14 and molten iron 12 are charged into a refining furnace 2 as iron sources, oxygen gas is then supplied into the refining furnace, the iron scrap in the refining furnace is melted by combustion heat by the oxygen gas of carbonaceous materials 15 supplied into the refining furnace and sensible heat of the molten iron, the iron scrap is recarburized by the carbonaceous material and the molten iron, and high-carbon molten iron having the carbon concentration of ≥3.0 mass% is produced in the refining furnace. Carbonaceous materials originating from biomass are used for a part of or the entire carbonaceous materials, and the amount of production of greenhouse gas is reduced thereby.

Description

本発明は、主原料として鉄スクラップ及び溶銑を使用し、上底吹き転炉型の精錬炉やアーク炉などを用いて高炭素溶鉄を製造する方法に関し、詳しくは、鉄スクラップの加熱及び加炭のために使用する炭材からの温室効果ガスの発生量を削減することのできる高炭素溶鉄の製造方法に関する。   The present invention relates to a method for producing high carbon molten iron using an upper bottom blown converter type refining furnace or arc furnace using iron scrap and hot metal as main raw materials, and more specifically, heating and carburizing of iron scrap. The present invention relates to a method for producing high-carbon molten iron capable of reducing the amount of greenhouse gas generated from carbonaceous materials used for the purpose.

近年、地球環境の保護及び地球温暖化防止の目的から、ＣＯ2ガス排出量の削減が重要な課題となっている。特に、製鉄所においては、ＣＯ2ガスの排出量削減は、企業の存続にも関わる最重要の課題となっている。一方、省資源及び環境問題の観点から、近年になって発生量の多い鉄スクラップを製鉄所でリサイクル使用して、鋼製品を製造することが技術課題となっている。これは、高炉での溶銑の製造では、鉄鉱石を還元し且つ溶融するために多大なエネルギーを要するのに対し、鉄スクラップは溶解熱のみを必要としており、鉄スクラップを利用することで、鉄鉱石の還元熱分のエネルギー使用量を少なくすることができ、省エネルギー及びＣＯ2ガス削減を実現できるという利点があるからである。 In recent years, reduction of CO 2 gas emissions has become an important issue for the purpose of protecting the global environment and preventing global warming. In particular, in steelworks, reducing CO 2 gas emissions is the most important issue related to the survival of companies. On the other hand, from the viewpoints of resource saving and environmental problems, in recent years, it has become a technical problem to manufacture steel products by recycling and recycling iron scraps that are generated in large quantities at steelworks. This is because hot metal production in a blast furnace requires a great deal of energy to reduce and melt iron ore, whereas iron scrap requires only heat of melting. This is because the amount of energy used for reducing heat of the stone can be reduced, and there is an advantage that energy saving and CO 2 gas reduction can be realized.

ところで、鉄スクラップを用いて溶融鉄を製造する精錬装置として、従来、一般的にアーク炉が使用されていた。しかし、従来のアーク炉の場合は、鉄スクラップの溶解に多くの電力を消費することから、我が国のように電力価格が高い場合には、製造コストが高くなる。そこで、アーク炉を使用することなく鉄スクラップを経済的に溶解する方法として、酸素ガス供給能力の高い転炉型精錬炉を用い、安価な炭材を酸素ガスで燃焼させ、炭材の燃焼熱を熱源として鉄スクラップを溶解し、溶融鉄を製造する方法が提案されている。   By the way, conventionally, an arc furnace has been generally used as a refining apparatus for producing molten iron using iron scrap. However, in the case of a conventional arc furnace, a large amount of electric power is consumed for melting iron scrap. Therefore, when the electric power price is high as in Japan, the manufacturing cost becomes high. Therefore, as a method for economically melting iron scrap without using an arc furnace, a converter-type smelting furnace with a high oxygen gas supply capacity is used, an inexpensive carbon material is burned with oxygen gas, and the combustion heat of the carbon material is There has been proposed a method for producing molten iron by melting iron scrap using as a heat source.

例えば、特許文献１には、酸素上吹き装置及び炉底に設置された炭材導入ノズルを備える酸素上底吹き転炉内で、前記炭材導入ノズルから吹き込む炭材を燃焼させて鉄スクラップなどの固体鉄原料を溶解して溶鋼を製造する方法において、転炉内で所望の出鋼量よりも１０〜３０％多量の溶鋼（「付加的溶鋼」という）を製造し、所望の出鋼量を出鋼した後、次のチャージで、前記付加的溶鋼を固体鉄原料と一緒に使用し、溶鋼を製造する方法が提案されている。   For example, in Patent Document 1, in an oxygen top bottom blowing converter equipped with an oxygen top blowing device and a carbon material introduction nozzle installed at the furnace bottom, the carbon material blown from the carbon material introduction nozzle is burned to produce iron scrap, etc. In the method of producing molten steel by melting the solid iron raw material, 10-30% more molten steel (referred to as “additional molten steel”) is produced in the converter than the desired amount of produced steel, and the desired amount of produced steel After the steel is produced, a method for producing the molten steel by using the additional molten steel together with the solid iron raw material at the next charge is proposed.

しかしながら、特許文献１で燃料として使用するコークスや黒鉛などの化石燃料由来の炭材は、燃焼すると大気中のＣＯ2ガス量を増加させる。地球温暖化防止の観点から、化石燃料由来の炭材は、その使用量を極力低減すべきである。 However, carbon materials derived from fossil fuels such as coke and graphite used as fuel in Patent Document 1 increase the amount of CO 2 gas in the atmosphere when burned. From the viewpoint of preventing global warming, the amount of fossil fuel-derived carbon should be reduced as much as possible.

また、特許文献２には、種湯と溶融スラグの存在する溶解専用転炉に、含鉄冷材、炭材、酸素、造滓材を供給して含鉄冷材を加炭・溶解して高炭素溶鉄を得る際に、前記溶解専用転炉からの出湯時に、高炭素溶鉄の一部を炉内に残し、次回の含鉄冷材の加炭・溶解操業の種湯として使用するとともに、溶解専用転炉内の溶融スラグの全部或いは一部を炉内に残し、次回の含鉄冷材の加炭・溶解操業時の鉄ダストの飛散を防止するカバースラグとして使用する技術が提案されている。   In Patent Document 2, iron-containing cold material, carbonaceous material, oxygen, and ironmaking material are supplied to a melting-only converter in which seed hot water and molten slag exist, and the iron-containing cold material is carburized and melted to obtain high carbon. When obtaining molten iron, at the time of discharging from the melting converter, a part of the high-carbon molten iron is left in the furnace and used as seed water for the next carburizing and melting operation of iron-containing cold material. A technique has been proposed in which all or part of the molten slag in the furnace is left in the furnace and used as a cover slag to prevent the scattering of iron dust during the next carburizing / melting operation of iron-containing cold material.

しかしながら、特許文献２の溶解専用転炉で加炭材及び燃料として使用するコークス、石炭などの炭材は硫黄の含有量が多く、製造される高炭素溶鉄の硫黄濃度が高くなり、出湯された後の高炭素溶鉄に対して脱硫処理が必要となる。また、特許文献１と同様に、特許文献２で燃料として使用するコークスや黒鉛などの化石燃料由来の炭材は、燃焼すると大気中のＣＯ2ガス量を増加させるので、地球温暖化防止の観点からその使用量は極力低減すべきである。 However, carbon materials such as coke and coal used as a carburized material and fuel in the converter exclusively for melting in Patent Document 2 have a high sulfur content, and the sulfur concentration of the high-carbon molten iron produced is high and discharged. Desulfurization treatment is required for the later high carbon molten iron. Similarly to Patent Document 1, carbon materials derived from fossil fuels such as coke and graphite used as fuel in Patent Document 2 increase the amount of CO 2 gas in the atmosphere when burned. Therefore, the amount used should be reduced as much as possible.

一方、特許文献３には、従来のアーク炉における電力原単位を改善するべく、鉄スクラップと溶銑とを鉄源としてアーク炉に装入し、且つ、該アーク炉に炭材及び酸素ガスを供給し、炭材の酸素ガスによる燃焼熱を利用して炭素濃度が４．０質量％以上の溶銑を製造する方法が提案されている。   On the other hand, in Patent Document 3, in order to improve the electric power consumption in a conventional arc furnace, iron scrap and hot metal are used as an iron source and charged into the arc furnace, and carbon materials and oxygen gas are supplied to the arc furnace. In addition, there has been proposed a method for producing hot metal having a carbon concentration of 4.0% by mass or more using the heat of combustion of carbonaceous material by oxygen gas.

しかしながら、特許文献３で燃料として使用するコークス、石炭、黒鉛などの化石燃料由来の炭材は、特許文献１、２と同様に、燃焼すると大気中のＣＯ2ガス量を増加させることから、地球温暖化防止の観点から、化石燃料由来の炭材は、その使用量を極力低減すべきである。 However, since carbon materials derived from fossil fuels such as coke, coal, and graphite used as fuel in Patent Document 3 increase the amount of CO 2 gas in the atmosphere when burned, as in Patent Documents 1 and 2 , From the viewpoint of preventing global warming, the amount of fossil fuel-derived carbon should be reduced as much as possible.

特開昭５６−５８９１６号公報JP-A-56-58916 特開平１−８２１４号公報Japanese Patent Laid-Open No. 1-8214 特開２０１１−１１１６２５号公報JP 2011-111625 A

本発明は上記事情に鑑みてなされたもので、その目的とするところは、鉄スクラップを用いて高炭素溶鉄を製造するにあたり、カーボンニュートラルであるバイオマス由来の炭材を、コークスや石炭などの化石燃料由来の炭材に替わる熱源及び加炭材として有効利用し、これによって温室効果ガス発生量を削減することのできる、鉄スクラップを用いた高炭素溶鉄の製造方法を提供することである。   The present invention has been made in view of the above circumstances, and the purpose of the present invention is to produce carbon-derived carbonaceous material, which is carbon neutral, using fossil such as coke and coal. It is intended to provide a method for producing high-carbon molten iron using iron scrap that can be effectively used as a heat source and a carburizing material that replaces a fuel-derived carbon material, and thereby reduce the amount of greenhouse gas generation.

上記課題を解決するための本発明の要旨は以下のとおりである。
［１］鉄スクラップ及び溶銑を鉄源として精錬炉内に装入し、次いで、該精錬炉内に酸素ガスを供給し、前記精錬炉内の前記鉄スクラップを精錬炉内に供給した炭材の前記酸素ガスによる燃焼熱及び前記溶銑の顕熱によって溶解するとともに、前記鉄スクラップを前記炭材及び前記溶銑によって加炭し、炭素濃度が３．０質量％以上の高炭素溶鉄を前記精錬炉内で製造する方法であって、前記炭材の一部または全部としてバイオマス由来の炭材を使用することを特徴とする、鉄スクラップを用いた高炭素溶鉄の製造方法。
［２］前記精錬炉が、前記酸素ガスを上吹き供給する上底吹き転炉型の精錬炉であることを特徴とする、上記［１］に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。
［３］前記精錬炉が、アーク炉であって、前記炭材の燃焼熱及び前記溶銑の顕熱に加えて発生するアークの熱で、前記鉄スクラップを溶解することを特徴とする、上記［１］に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。
［４］前記バイオマス由来の炭材の硫黄濃度が０．１０質量％以下であることを特徴とする、上記［１］ないし上記［３］の何れか１項に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。
［５］前記バイオマス由来の炭材の総添加量をＸ（kg-炭材/t-溶鉄）、該炭材の硫黄濃度をａ（質量％）、精錬前の溶銑及び鉄スクラップの硫黄濃度の加重平均値をｂ（質量％）、精錬終了時の高炭素溶鉄の許容最大硫黄濃度をｃ（質量％）としたとき、前記炭材の総添加量Ｘを下記の（１）式で求められる値とし、この炭材の総添加量Ｘに基づいて前記鉄スクラップの装入量を決定することを特徴とする、上記［１］ないし上記［４］の何れか１項に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。
Ｘ＝［（ｃ−ｂ）／ａ］×１０００ …（１）
［６］前記バイオマス由来の炭材が、パームヤシ殻由来のバイオマス炭、パームヤシ空果房由来のバイオマス炭、パームヤシ幹由来のバイオマス炭のうちの何れか１種または２種以上であることを特徴とする、上記［１］ないし上記［５］の何れか１項に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。
［７］前記精錬炉内への酸素ガスの供給中に、鉄鉱石、鉄鉱石の焼結鉱、ミルスケール、製鉄ダスト、磁選屑、鋼の切削屑からなる鉄源のうちの何れか１種または２種以上の鉄源を前記精錬炉内に投入することを特徴とする、上記［１］ないし上記［６］の何れか１項に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。 The gist of the present invention for solving the above problems is as follows.
[1] Charcoal material in which iron scrap and hot metal are charged into a smelting furnace as an iron source, oxygen gas is supplied into the smelting furnace, and the iron scrap in the smelting furnace is supplied into the smelting furnace. While melting by the combustion heat by the oxygen gas and the sensible heat of the hot metal, the iron scrap is carburized by the carbon material and the hot metal, and high carbon molten iron having a carbon concentration of 3.0% by mass or more is contained in the smelting furnace. A method for producing high-carbon molten iron using iron scrap, characterized in that a biomass-derived carbon material is used as part or all of the carbon material.
[2] Production of high carbon molten iron using iron scrap according to [1], wherein the smelting furnace is an upper bottom blowing converter type smelting furnace for supplying the oxygen gas by blowing up Method.
[3] The smelting furnace is an arc furnace, and the iron scrap is melted by the heat of the arc generated in addition to the combustion heat of the carbonaceous material and the sensible heat of the hot metal. 1] The manufacturing method of the high carbon molten iron using the iron scrap as described in 1].
[4] The high concentration using the iron scrap according to any one of [1] to [3] above, wherein a sulfur concentration of the biomass-derived carbon material is 0.10% by mass or less. A method for producing molten carbon.
[5] X (kg-carbon material / t-molten iron) is the total amount of the biomass-derived carbon material, the sulfur concentration of the carbon material is a (mass%), the hot metal before refining, and the sulfur concentration of iron scrap. When the weighted average value is b (mass%) and the allowable maximum sulfur concentration of the high-carbon molten iron at the end of refining is c (mass%), the total amount X of the carbonaceous material can be obtained by the following equation (1). The iron scrap according to any one of [1] to [4] above, wherein the iron scrap is determined based on a total amount X of the carbon material and the amount of the iron scrap is determined. The manufacturing method of the high carbon molten iron used.
X = [(c−b) / a] × 1000 (1)
[6] The charcoal material derived from biomass is any one or more of biomass charcoal derived from palm coconut shell, biomass charcoal derived from palm palm empty fruit bunch, and biomass charcoal derived from palm palm trunk, A method for producing high-carbon molten iron using the iron scrap according to any one of [1] to [5] above.
[7] During supply of oxygen gas into the smelting furnace, any one of iron sources comprising iron ore, iron ore sintered ore, mill scale, iron making dust, magnetic separation scrap, and steel cutting scrap Alternatively, the method for producing high-carbon molten iron using iron scrap according to any one of [1] to [6] above, wherein two or more types of iron sources are put into the smelting furnace.

本発明によれば、主原料として鉄スクラップ及び溶銑を使用して高炭素溶鉄を製造する際に、熱源並びに加炭材としてカーボンニュートラルであるバイオマス由来の炭材を使用するので、バイオマス由来の炭材の使用比率に応じて、熱源の燃焼による温室効果ガスの発生量を削減することが実現される。また、硫黄濃度が０．１０質量％以下のバイオマス由来の炭材を使用した場合には、炭材から高炭素溶鉄への硫黄の混入が抑制され、製造した高炭素溶鉄は、脱硫処理を施さなくても次工程で運用することができるとともに、硫黄混入に起因する熱源不足を解消させて大量のバイオマス由来の炭材の使用が可能となり、鉄スクラップの配合比率を高めることができ、高炭素溶鉄の生産量を増加させることが可能となる。   According to the present invention, when producing high-carbon molten iron using iron scrap and hot metal as the main raw material, the carbon-derived carbonaceous material that is carbon neutral is used as the heat source and the carburizing material. According to the usage ratio of the material, it is possible to reduce the amount of greenhouse gas generated by the combustion of the heat source. Moreover, when a biomass-derived carbon material having a sulfur concentration of 0.10% by mass or less is used, mixing of sulfur from the carbon material into the high carbon molten iron is suppressed, and the produced high carbon molten iron is subjected to desulfurization treatment. Without being able to operate in the next process, it becomes possible to use a large amount of biomass-derived charcoal by eliminating the shortage of heat source due to sulfur contamination, increasing the proportion of iron scrap, and high carbon It becomes possible to increase the production amount of molten iron.

本発明を適用した上底吹き転炉型精錬炉設備の縦断面の概要図である。It is a schematic diagram of the longitudinal section of the top bottom blowing converter type refining furnace equipment to which the present invention is applied. 本発明を適用したアーク炉の縦断面の概要図である。It is a schematic diagram of the longitudinal section of the arc furnace to which the present invention is applied.

以下、添付図面を参照して本発明を具体的に説明する。   Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

先ず、本発明を上底吹き転炉型精錬炉設備に適用した第１の形態例を説明する。図１は、本発明を適用した上底吹き転炉型精錬炉設備の縦断面の概要図である。   First, a first embodiment in which the present invention is applied to an upper bottom blowing converter type refining furnace facility will be described. FIG. 1 is a schematic view of a vertical section of an upper bottom blown converter type refining furnace equipment to which the present invention is applied.

転炉型精錬炉設備１は、その内部に鉄スクラップ１４及び溶銑１２が装入され、装入された鉄スクラップ１４及び溶銑１２から高炭素溶鉄を製造する精錬炉本体２と、精錬炉本体２の上部の炉口３を通って精錬炉本体２の内部空間への上下移動が可能な上吹き酸素ランス４と、炉口３を覆うダクト８を介して精錬炉本体２から発生する排ガス（主にＣＯガス）を回収するガス回収装置（図示せず）と、ホッパー９、９ａ、切り出し装置１０、１０ａ及びシュート１１がその一部分を構成する原料装入装置と、から構成されている。精錬炉本体２には、その炉底を貫通する底吹き羽口５と、その側壁を貫通する出湯口７とが設置されている。底吹き羽口５はガス導入管６と連通しており、底吹き羽口５からは、ガス導入管６を介して供給される、Ａｒガスや窒素ガスなどの攪拌用ガス或いは精錬用酸素ガスが、底吹きガスとして吹き込まれるように構成され、また、シュート１１はダクト８を貫通して炉口３の直上に至り、シュート１１を介して炉口３から原料が炉内に装入されるように構成されている。   The converter-type refining furnace equipment 1 has iron scrap 14 and hot metal 12 charged therein, a refining furnace main body 2 for producing high carbon molten iron from the charged iron scrap 14 and hot metal 12, and a refining furnace main body 2. The exhaust gas generated from the refining furnace main body 2 through the upper blown oxygen lance 4 that can move up and down to the internal space of the refining furnace main body 2 through the upper furnace port 3 and the duct 8 that covers the furnace port 3 (main In addition, a gas recovery device (not shown) for recovering CO gas), a hopper 9, 9a, a cutting device 10, 10a, and a chute 11 constituting a part of the raw material charging device. The refining furnace main body 2 is provided with a bottom blowing tuyere 5 penetrating the furnace bottom and a hot water outlet 7 penetrating the side wall. The bottom blowing tuyere 5 communicates with a gas introduction pipe 6, and stirring gas such as Ar gas or nitrogen gas or refining oxygen gas supplied from the bottom blowing tuyere 5 through the gas introduction pipe 6. However, the chute 11 passes through the duct 8 and reaches directly above the furnace port 3, and the raw material is charged into the furnace from the furnace port 3 through the chute 11. It is configured as follows.

このように構成される上底吹き転炉型精錬炉設備１を用い、以下のようにして本発明を実施する。   Using the top bottom blown converter type refining furnace equipment 1 configured as described above, the present invention is carried out as follows.

先ず、精錬炉本体２に主原料として、鉄スクラップ１４と溶銑１２とを装入する。本発明において、鉄スクラップ１４は、基本的に、精錬炉本体２に供給する炭材１５と、上吹きランス４から精錬炉本体２に供給する酸素ガスとの反応熱、つまり、炭材１５の燃焼熱によって溶解するので、鉄スクラップ１４の配合比率（鉄スクラップの配合比率＝鉄スクラップ装入量×１００／(溶銑装入量＋鉄スクラップ装入量)）は、炭材１５からの硫黄の混入を考慮しない場合には特に規定する必要はなく、炭材１５の使用量に応じて設定すればよい。換言すれば、鉄スクラップ１４の任意の配合比率に応じて炭材１５の使用量を設定すればよい。但し、鉄スクラップ１４の配合比率を高くし過ぎると、溶解時間が長くなるので、鉄スクラップ１４の配合比率は最大値で５０質量％程度とすればよい。使用する溶銑１２には、必要に応じて脱硫、脱珪、脱燐の予備処理を予め実施する。   First, iron scrap 14 and molten iron 12 are charged into the refining furnace body 2 as main raw materials. In the present invention, the iron scrap 14 is basically the reaction heat between the carbon material 15 supplied to the refining furnace body 2 and the oxygen gas supplied from the top blowing lance 4 to the refining furnace body 2, that is, the carbon material 15. Since it is melted by the combustion heat, the mixing ratio of iron scrap 14 (the mixing ratio of iron scrap = iron scrap charging amount x 100 / (molten metal charging amount + iron scrap charging amount)) is the amount of sulfur from the carbonaceous material 15 When mixing is not taken into consideration, it is not necessary to specify in particular, and it may be set according to the amount of carbon material 15 used. In other words, what is necessary is just to set the usage-amount of the carbonaceous material 15 according to the arbitrary mixture ratios of the iron scrap 14. FIG. However, if the mixing ratio of the iron scrap 14 is increased too much, the melting time becomes longer. Therefore, the mixing ratio of the iron scrap 14 may be about 50% by mass at the maximum value. The hot metal 12 to be used is preliminarily subjected to desulfurization, desiliconization, and dephosphorization pretreatment as necessary.

熱源である炭材１５の使用量に基づいて設定した配合比率に沿って鉄スクラップ１４を炉内に装入し、次いで、前記配合比率に沿って溶銑１２を炉内に装入する。その後、ホッパー９に収納されたバイオマス由来の炭材１５を切り出し装置１０により所定量切り出し、シュート１１を介して炉口３から炉内に熱源として装入する。この場合、炭材１５の一部を、鉄スクラップ１４とともに予め炉内に装入しても構わない。更に、炉内に精錬用の溶融スラグ１３を形成させるべく、生石灰、蛍石、ドロマイトなどの造滓材を、原料装入装置（図示せず）を介して精錬炉本体２の内部に装入する。また更に、炭材１５の添加量から算出される発熱量と、造滓剤の添加量及び出湯時の高炭素溶鉄の温度目標値などとを対比した熱計算において、熱余裕が有る場合には、この熱余裕に応じた量の鉄源１６をホッパー９ａから切り出し装置１０ａによって切り出し、シュート１１を介して炉内に装入する。ホッパー９ａから供給される鉄源１６は、冷却材として機能する。   The iron scrap 14 is charged into the furnace along the blending ratio set based on the amount of the carbonaceous material 15 that is the heat source, and then the hot metal 12 is loaded into the furnace along the blending ratio. After that, a predetermined amount of the biomass-derived carbon material 15 stored in the hopper 9 is cut out by the cutting device 10 and charged into the furnace from the furnace port 3 through the chute 11 as a heat source. In this case, a part of the carbon material 15 may be charged in the furnace together with the iron scrap 14 in advance. Furthermore, in order to form molten slag 13 for refining in the furnace, a fossil material such as quick lime, fluorite, and dolomite is charged into the refining furnace main body 2 through a raw material charging device (not shown). To do. Furthermore, in the heat calculation comparing the calorific value calculated from the addition amount of the carbonaceous material 15 with the addition amount of the slagging agent and the target temperature value of the high carbon molten iron at the time of tapping, there is a thermal margin. The iron source 16 in an amount corresponding to this heat margin is cut out from the hopper 9a by the cutting device 10a and charged into the furnace via the chute 11. The iron source 16 supplied from the hopper 9a functions as a coolant.

この鉄源１６としては、鉄鉱石、鉄鉱石の焼結鉱、ミルスケール、製鉄ダスト、磁選屑、及び機械工場で発生する鋼の切削屑のうちの何れか１種または２種以上を適宜選択して使用する。尚、鉄源１６にＦｅＯやＦｅ2Ｏ3が含まれる場合も、これらは炉内で溶銑１２及び炭材１５に含有される炭素によって還元され鉄となるので、資源の有効活用がなされる。また、磁選屑とは、転炉スラグなどに混入する地金分を、破砕したスラグから磁力選別によって回収したものである。 As the iron source 16, any one or more of iron ore, iron ore sintered ore, mill scale, iron making dust, magnetic separation scrap, and steel cutting scrap generated in a machine factory is appropriately selected. And use it. Even when the iron source 16 contains FeO or Fe 2 O 3 , these are reduced to iron by the carbon contained in the hot metal 12 and the carbon material 15 in the furnace, so that the resources are effectively used. Moreover, magnetic separation waste collect | recovers the metal components mixed in converter slag etc. from the crushed slag by magnetic separation.

その後、底吹き羽口５から底吹きガスを吹き込みながら、上吹き酸素ランス４から酸素ガスを炉内に供給して精錬を開始する。この場合、上吹き酸素ランス４から供給する酸素ガスが溶銑１２に直接衝突すると、溶銑１２の脱炭反応（２Ｃ＋Ｏ2＝２ＣＯ）が起こり、製造される高炭素溶鉄の炭素濃度が低下するので、供給する酸素ガスが、溶銑１２の脱炭反応に極力費やされず、炭材１５の燃焼に主に費やされるように、上吹き酸素ランス４からの酸素ガスの吹き込み流量及び吹き込み圧力を設定する。 Thereafter, while blowing the bottom blowing gas from the bottom blowing tuyere 5, oxygen gas is supplied from the top blowing oxygen lance 4 into the furnace to start refining. In this case, when the oxygen gas supplied from the top blown oxygen lance 4 directly collides with the molten iron 12, a decarburization reaction of the molten iron 12 (2C + O 2 = 2CO) occurs, and the carbon concentration of the produced high carbon molten iron decreases. The flow rate and pressure of the oxygen gas blown from the top blown oxygen lance 4 are set so that the oxygen gas to be supplied is not consumed as much as possible in the decarburization reaction of the hot metal 12 but is mainly consumed in the combustion of the carbonaceous material 15.

炭材１５は酸素ガスにより、「２Ｃ＋Ｏ2＝２ＣＯ」なる反応式に沿って燃焼し、その燃焼熱が溶融スラグ１３を介して溶銑１２に伝達され、溶銑１２に埋没した鉄スクラップ１４が溶解する。但し、溶銑１２の脱炭反応による発熱も鉄スクラップ１４の溶解に寄与するので、溶銑１２の脱炭反応を完全に防止する必要はない。炭材１５の一部は溶銑１２に溶解し、鉄スクラップ１４の溶解に伴って希釈される溶銑１２の炭素濃度を上昇させる。つまり、炭材１５は、鉄スクラップ１４の溶解によって生成する溶融鉄及び溶銑１２を加炭する機能を有している。溶銑１２の脱炭反応を極力抑制すると同時に炭材１５が加炭材として機能することで、製造される高炭素溶鉄の炭素濃度は３．０質量％以上に確保される。そして、この精錬中においても、炭材１５と、この炭材１５の添加量に応じた量の鉄源１６とを、シュート１１を介して炉口３より適宜炉内に装入する。 The carbonaceous material 15 is combusted by oxygen gas along the reaction formula “2C + O 2 = 2CO”, and the combustion heat is transmitted to the hot metal 12 through the molten slag 13, and the iron scrap 14 buried in the hot metal 12 is melted. . However, since the heat generated by the decarburization reaction of the hot metal 12 also contributes to the dissolution of the iron scrap 14, it is not necessary to completely prevent the decarburization reaction of the hot metal 12. A part of the carbon material 15 is dissolved in the hot metal 12, and the carbon concentration of the hot metal 12 diluted with the dissolution of the iron scrap 14 is increased. That is, the carbon material 15 has a function of carburizing the molten iron and the molten iron 12 generated by melting the iron scrap 14. By suppressing the decarburization reaction of the hot metal 12 as much as possible, the carbon material 15 functions as a carburizing material, so that the carbon concentration of the manufactured high carbon molten iron is ensured to be 3.0 mass% or more. During the refining, the carbon material 15 and the iron source 16 in an amount corresponding to the added amount of the carbon material 15 are appropriately charged into the furnace through the chute 11 from the furnace port 3.

所定量の炭材１５及び酸素ガスが供給され、鉄スクラップ１４が溶解して所定の温度及び炭素濃度が３．０質量％以上である高炭素溶鉄が生成されたなら、必要に応じて図示せぬ原料装入装置からＦｅ−Ｍｎ合金やＳｉ−Ｍｎ合金などを高炭素溶鉄に投入し、その後、図示せぬ傾動装置にて精錬炉本体２を傾動させ、出湯口７から取鍋（図示せずに）に高炭素溶鉄を排出して、鉄スクラップ１４を用いた高炭素溶鉄の製造を終了する。製造された高炭素溶鉄は、必要に応じて脱硫処理が施された後に転炉での脱炭精錬に供される。   If a predetermined amount of the carbonaceous material 15 and oxygen gas are supplied, and the iron scrap 14 is melted to produce a high carbon molten iron having a predetermined temperature and a carbon concentration of 3.0% by mass or more, it can be illustrated as necessary. Fe-Mn alloy, Si-Mn alloy, etc. are poured into high carbon molten iron from a raw material charging device, and then the smelting furnace body 2 is tilted by a tilting device (not shown), and a ladle (not shown) is drawn from the tap 7. 1), the high carbon molten iron is discharged, and the production of the high carbon molten iron using the iron scrap 14 is completed. The manufactured high carbon molten iron is subjected to desulfurization treatment as necessary, and then subjected to decarburization refining in a converter.

ところで、バイオマス由来の炭材１５も、化石燃料由来の炭材と同様に、不純物として硫黄を含有している。上記の説明では、バイオマス由来の炭材１５の添加量を規定しておらず、バイオマス由来の炭材１５の添加量が多くなれば、製造される高炭素溶鉄の硫黄濃度が目標値を超える虞がある。製造される高炭素溶鉄へのバイオマス由来の炭材１５による硫黄の汚染を未然に防止するためには、以下の方法を採用することが好ましい。   By the way, the biomass-derived carbon material 15 also contains sulfur as an impurity, like the fossil fuel-derived carbon material. In the above description, the addition amount of the biomass-derived carbon material 15 is not prescribed, and if the addition amount of the biomass-derived carbon material 15 increases, the sulfur concentration of the manufactured high carbon molten iron may exceed the target value. There is. In order to prevent the contamination of sulfur by the biomass-derived carbon material 15 to the high carbon molten iron to be produced, it is preferable to employ the following method.

即ち、バイオマス由来の炭材１５の１チャージあたりの総添加量をＸ（kg-炭材/t-溶鉄）、この炭材１５の硫黄濃度をａ（質量％）、精錬前の溶銑１２及び鉄スクラップ１４の硫黄濃度の加重平均値をｂ（質量％）、精錬終了時の高炭素溶鉄の許容最大硫黄濃度をｃ（質量％）とすると、炭材１５の総添加量Ｘの最大値は、下記の（１）式により算出される。
Ｘ＝［（ｃ−ｂ）／ａ］×１０００ …（１）
熱源及び加炭材としてバイオマス由来の炭材１５のみを添加する条件で、バイオマス由来の炭材１５の添加量が、（１）式で算出される総添加量Ｘ以下の添加量であるならば、炭材１５の添加による硫黄濃度の上昇を、高炭素溶鉄の許容最大硫黄濃度ｃ以下に抑えることができる。コークスなどの従来の化石燃料由来の炭材を併用する場合には、化石燃料由来の炭材に含有される硫黄による硫黄濃度の上昇分を考慮してバイオマス由来の炭材１５の最大添加量を決める必要がある。つまり、化石燃料由来の炭材によって持ち込まれる硫黄分と、バイオマス由来の炭材１５によって持ち込まれる硫黄分との合計量が、高炭素溶鉄の許容最大硫黄濃度ｃを超えないようにする必要がある。 That is, the total amount added per one charge of biomass-derived carbon material 15 is X (kg-carbon material / t-molten iron), the sulfur concentration of this carbon material 15 is a (mass%), hot metal 12 and iron before refining. When the weighted average value of the sulfur concentration of the scrap 14 is b (mass%) and the allowable maximum sulfur concentration of the high carbon molten iron at the end of refining is c (mass%), the maximum value of the total addition amount X of the carbonaceous material 15 is It is calculated by the following equation (1).
X = [(c−b) / a] × 1000 (1)
If only the biomass-derived carbon material 15 is added as a heat source and a carburized material, the amount of biomass-derived carbon material 15 added is equal to or less than the total addition amount X calculated by equation (1) The increase in the sulfur concentration due to the addition of the carbonaceous material 15 can be suppressed to the allowable maximum sulfur concentration c or less of the high carbon molten iron. When a conventional fossil fuel-derived carbon material such as coke is used in combination, the maximum addition amount of the biomass-derived carbon material 15 is set in consideration of an increase in sulfur concentration due to sulfur contained in the fossil fuel-derived carbon material. It is necessary to decide. That is, it is necessary that the total amount of the sulfur content introduced by the fossil fuel-derived carbon material and the sulfur content introduced by the biomass-derived carbon material 15 does not exceed the allowable maximum sulfur concentration c of the high carbon molten iron. .

また、熱源及び加炭材としてバイオマス由来の炭材１５のみを添加するとし、バイオマス由来の炭材１５の添加量を（１）式で算出される総添加量Ｘとした条件で鉄スクラップ１４の配合比率を求めれば、求められる鉄スクラップ１４の配合比率は、製造される高炭素溶鉄に脱硫処理を施さずに済む範囲内の最大値となる。   Moreover, when only the biomass-derived carbon material 15 is added as a heat source and a carburized material, the amount of the biomass-derived carbon material 15 is set to the total addition amount X calculated by the equation (1). If the blending ratio is obtained, the obtained blending ratio of the iron scrap 14 is the maximum value within a range in which the manufactured high carbon molten iron does not need to be desulfurized.

但し、バイオマス由来の炭材１５の添加量を最大値とし、且つ、鉄スクラップ１４の配合比率も最大値とした場合は、精錬終了時の高炭素溶鉄の硫黄濃度が許容上限値となる。従って、それ以上の炭材の添加は、バイオマス由来の炭材１５であっても、高炭素溶鉄の硫黄濃度が許容最大硫黄濃度ｃ以上になることを意味しており、従って、この場合には、精錬の途中で炭材を投入することは好ましくなく、また、精錬終了時の高炭素溶鉄の測温結果が目標値よりも低い場合も、炭材を投入することは好ましくない。硫黄濃度の上昇を伴わない熱源としてはＦｅ−Ｓｉ合金や金属Ａｌなどを用いることができる。   However, when the addition amount of the carbonaceous material 15 derived from biomass is set to the maximum value and the blending ratio of the iron scrap 14 is also set to the maximum value, the sulfur concentration of the high carbon molten iron at the end of the refining becomes the allowable upper limit value. Therefore, the addition of more carbon material means that the sulfur concentration of the high carbon molten iron is equal to or higher than the allowable maximum sulfur concentration c even in the case of the biomass-derived carbon material 15. In addition, it is not preferable to input the carbonaceous material during the refining, and it is not preferable to input the carbonaceous material even when the temperature measurement result of the high carbon molten iron at the end of the refining is lower than the target value. As a heat source not accompanied by an increase in the sulfur concentration, an Fe—Si alloy, metal Al, or the like can be used.

使用する炭材１５としては、バイオマス由来であればカーボンニュートラルであり、温室効果ガスは発生しないので、温室効果ガス発生の観点からは特に特定する必要はない。但し、バイオマス由来の炭材１５も上記のように硫黄を含有しており、大量の添加は高炭素溶鉄の硫黄濃度が上昇するという問題が生じる。種々検討した結果、炭材１５の硫黄濃度が０．１０質量％以下であれば、炭材添加による高炭素溶鉄中の硫黄濃度の上昇は少なく、大量の炭材１５を熱源として使用できることが分った。つまり、使用するバイオマス由来の炭材１５としては、硫黄濃度が０．１０質量％以下の炭材であることが好ましい。   The carbon material 15 to be used is carbon neutral as long as it is derived from biomass, and no greenhouse gas is generated. Therefore, it is not particularly necessary to specify from the viewpoint of generating a greenhouse gas. However, the biomass-derived carbon material 15 also contains sulfur as described above, and the addition of a large amount causes a problem that the sulfur concentration of the high carbon molten iron increases. As a result of various studies, if the sulfur concentration of the carbon material 15 is 0.10% by mass or less, the increase in the sulfur concentration in the high carbon molten iron due to the addition of the carbon material is small, and it is understood that a large amount of the carbon material 15 can be used as a heat source. It was. That is, it is preferable that the biomass-derived carbon material 15 to be used is a carbon material having a sulfur concentration of 0.10% by mass or less.

この観点から、バイオマス由来の炭材１５としては、パームヤシ殻由来のバイオマス炭（硫黄濃度≒０．０５質量％）、パームヤシ空果房由来のバイオマス炭（硫黄濃度≒０．０７質量％）、パームヤシ幹由来のバイオマス炭（硫黄濃度≒０．１０質量％）のうちの何れか１種または２種以上を使用することが好ましい。   From this viewpoint, the biomass-derived carbon material 15 includes biomass coal derived from palm coconut shell (sulfur concentration ≈ 0.05 mass%), biomass coal derived from palm palm empty fruit bunches (sulfur concentration ≈ 0.07 mass%), palm palm It is preferable to use any one or more of trunk-derived biomass charcoal (sulfur concentration≈0.10 mass%).

例えば、精錬前の溶銑１２及び鉄スクラップ１４の硫黄濃度の加重平均値ｂと、精錬終了時の高炭素溶鉄の許容最大硫黄濃度ｃとの差、つまり、精錬中に炭材から混入する硫黄の濃度上昇の許容される上限値が０．００１質量％である場合に、炭材として硫黄濃度が０．５質量％の一般的なコークスを利用した場合には、硫黄濃度の規制から炭材原単位として最大２kg-炭材/t-溶鉄のコークスを添加するだけであるが、硫黄濃度が０．１０質量％のバイオマス炭を利用した場合は、硫黄濃度がコークスと比較して５分の１であることから、５倍の添加量である１０kg-炭材/t-溶鉄のバイオマス炭を添加することができ、添加する熱源の増加に伴って多くの鉄スクラップ１４や鉄源１６を配合することが可能となる。尚、高炭素溶鉄の許容最大硫黄濃度ｃは、この高炭素溶鉄を転炉にて脱炭精錬して製造される鋼種の硫黄濃度規格によって決定される。   For example, the difference between the weighted average value b of the sulfur concentration of the hot metal 12 and iron scrap 14 before refining and the allowable maximum sulfur concentration c of high carbon molten iron at the end of refining, that is, the amount of sulfur mixed from the carbonaceous material during refining When the upper limit of the allowable increase in concentration is 0.001% by mass, when using general coke with a sulfur concentration of 0.5% by mass as the carbon material, the carbon material Only 2kg-carbon / t-molten coke is added as a unit, but when using biomass charcoal with a sulfur concentration of 0.10 mass%, the sulfur concentration is 1/5 compared to coke. Therefore, it is possible to add 10 kg-charcoal material / t-molten biomass charcoal, which is 5 times the amount of addition, and mix many iron scraps 14 and iron sources 16 as the heat source to be added increases. It becomes possible. The allowable maximum sulfur concentration c of high carbon molten iron is determined by the sulfur concentration standard of a steel type produced by decarburizing and refining this high carbon molten iron in a converter.

次いで、本発明をアーク炉に適用した第２の形態例を説明する。図２は、本発明を適用したアーク炉の縦断面の概要図である。   Next, a second embodiment in which the present invention is applied to an arc furnace will be described. FIG. 2 is a schematic diagram of a longitudinal section of an arc furnace to which the present invention is applied.

図２において、符号２１は直流式アーク炉、２２は溶解室、２３は炉蓋、２４は上部電極、２５は炉底電極、２６は溶銑装入樋、２７は溶銑を収容する装入鍋、２８はクレーン、２９は出湯口、３０は酸素ガス供給ランス、３１は炭材供給ランス、３２は原料投入シュート、３３はアークである。尚、符号１２は溶銑、１４は鉄スクラップ、１５は炭材、１６は鉄源であり、これらは第１の形態例の図１と同一である。   In FIG. 2, reference numeral 21 is a DC arc furnace, 22 is a melting chamber, 23 is a furnace lid, 24 is an upper electrode, 25 is a furnace bottom electrode, 26 is a hot metal charging rod, 27 is a charging pan for containing hot metal, 28 is a crane, 29 is a tap, 30 is an oxygen gas supply lance, 31 is a carbonaceous material supply lance, 32 is a raw material charging chute, and 33 is an arc. In addition, the code | symbol 12 is hot metal, 14 is an iron scrap, 15 is a carbonaceous material, 16 is an iron source, These are the same as FIG. 1 of the 1st form example.

炉蓋２３を外して溶解室２２の内部に鉄スクラップ１４を装入し、鉄スクラップ１４の装入後、直流式アーク炉２１の側壁を貫通して設置される溶銑装入樋２６を介して、クレーン２８で吊り上げられた装入鍋２７から溶銑１２を溶解室２２に装入する。この場合、鉄スクラップ１４は、アーク３３の熱、溶銑１２の顕熱及び炭材１５の燃焼熱によって溶解されるので、鉄スクラップ１４の配合比率は、第１の形態例の転炉型精錬炉設備１を使用した場合と異なり、炭材１５の供給量に拘わらず、任意の値を設定することができる。   The furnace lid 23 is removed, and the iron scrap 14 is charged into the melting chamber 22. After the iron scrap 14 is charged, the iron scrap 14 is inserted through a hot metal charging rod 26 that penetrates the side wall of the DC arc furnace 21. The molten iron 12 is charged into the melting chamber 22 from the charging pot 27 lifted by the crane 28. In this case, since the iron scrap 14 is melted by the heat of the arc 33, the sensible heat of the hot metal 12, and the combustion heat of the carbonaceous material 15, the mixing ratio of the iron scrap 14 is the converter type refining furnace of the first embodiment. Unlike the case where the facility 1 is used, an arbitrary value can be set regardless of the supply amount of the carbonaceous material 15.

所定量の溶銑１２が装入されたなら、装入鍋２７からの溶銑１２の供給を終え、上部電極２４と炉底電極２５との間に直流電流を給電し、上部電極２４と炉底電極２５との間、または、装入された鉄スクラップ１４と上部電極２４との間でアーク３３を発生させる。そして、発生するアーク熱及び溶銑１２の顕熱により鉄スクラップ１４を溶解して溶融鉄（図示せず）を生成させる。生成する溶融鉄は溶銑１２と混合し、溶銑１２の炭素濃度は希釈される。   When a predetermined amount of hot metal 12 is charged, the supply of hot metal 12 from the charging pan 27 is finished, a direct current is supplied between the upper electrode 24 and the furnace bottom electrode 25, and the upper electrode 24 and the furnace bottom electrode are supplied. An arc 33 is generated between the iron scrap 14 and the upper electrode 24. Then, the iron scrap 14 is melted by the generated arc heat and the sensible heat of the hot metal 12 to generate molten iron (not shown). The molten iron produced is mixed with the hot metal 12 and the carbon concentration of the hot metal 12 is diluted.

通電後、酸素ガス供給ランス３０及び炭材供給ランス３１の溶解室２２への挿入が可能となったなら、酸素ガス供給ランス３０から酸素ガスを、また、炭材供給ランス３１から、バイオマス由来の炭材１５を、溶解室内の溶銑１２または溶融スラグに向けて吹き付ける。吹き付けられた炭材１５は、吹き付けられた酸素ガスと反応して燃焼熱を発生し、鉄スクラップ１４を溶解するための補助熱源として機能し、電力使用量を軽減する。また、炭材１５の一部は、生成する溶融鉄及び炉内の溶銑１２に溶け込み、鉄スクラップ１４の溶解に伴って希釈される溶銑１２の炭素濃度を上昇させ、炭素濃度が３．０質量％以上の高炭素溶鉄が生成される。この場合に、炭材１５の一部を、鉄スクラップ１４の炉内への装入と同時に、予め溶解室２２に装入しても構わない。尚、炭材１５は、生成する溶融鉄によって炭素濃度が希釈される溶銑１２の炭素濃度を高めるための加炭材としての役割を担うので、供給される酸素ガスの化学当量よりも多い量の炭材１５を供給する。   When the oxygen gas supply lance 30 and the carbonaceous material supply lance 31 can be inserted into the melting chamber 22 after energization, oxygen gas is supplied from the oxygen gas supply lance 30, and from the carbonaceous material supply lance 31, it is derived from biomass. The carbon material 15 is sprayed toward the hot metal 12 or molten slag in the melting chamber. The sprayed carbon material 15 reacts with the sprayed oxygen gas to generate combustion heat, functions as an auxiliary heat source for melting the iron scrap 14, and reduces power consumption. Further, a part of the carbonaceous material 15 is melted into the molten iron to be produced and the molten iron 12 in the furnace, and the carbon concentration of the molten iron 12 diluted with the melting of the iron scrap 14 is increased, and the carbon concentration is 3.0 mass. % Of high-carbon molten iron is produced. In this case, a part of the carbonaceous material 15 may be charged into the melting chamber 22 in advance simultaneously with the charging of the iron scrap 14 into the furnace. In addition, since the carbonaceous material 15 plays the role as a carbonized material for raising the carbon concentration of the hot metal 12 whose carbon concentration is diluted by the molten iron to be generated, the amount of the carbonaceous material 15 is larger than the chemical equivalent of the supplied oxygen gas. Carbon material 15 is supplied.

また、鉄スクラップ１４が溶解し始めたなら、生産性を向上させるために、原料投入シュート３２を介して鉄源１６を溶解室２２に装入することが好ましい。また、鉄スクラップ１４が溶解し始めたなら、生石灰などのフラックスを溶解室２２に装入して溶融スラグを溶銑１２の上に形成させ、溶銑１２の酸化を防止するとともに保温を図ることが好ましい。   In addition, when the iron scrap 14 starts to melt, it is preferable to charge the iron source 16 into the melting chamber 22 through the raw material charging chute 32 in order to improve productivity. Further, when the iron scrap 14 starts to melt, it is preferable that a flux such as quick lime is charged into the melting chamber 22 to form molten slag on the hot metal 12 to prevent the hot metal 12 from being oxidized and to keep warm. .

溶解室内に所定量、所定温度で且つ炭素濃度が３．０質量％以上である高炭素溶鉄が生成されたなら、傾動装置（図示せず）によって溶解室２２を出湯口２９の側へ傾動させ、出湯口２９から、炭素濃度が３．０質量％以上の高炭素溶鉄を取鍋などの保持容器（図示せず）へ出湯する。出湯後、新たに鉄スクラップ１４及び溶銑１２を溶解室２２に装入し、次回ヒートの溶解を開始する。製造された高炭素溶鉄は、必要に応じて脱硫処理が施された後に転炉での脱炭精錬に供される。   If high carbon molten iron having a predetermined amount, a predetermined temperature, and a carbon concentration of 3.0% by mass or more is produced in the melting chamber, the melting chamber 22 is tilted toward the outlet 29 by a tilting device (not shown). From the tap 29, the high carbon molten iron having a carbon concentration of 3.0% by mass or more is poured into a holding container (not shown) such as a ladle. After pouring hot water, iron scrap 14 and hot metal 12 are newly charged into the melting chamber 22, and melting of the next heat is started. The manufactured high carbon molten iron is subjected to desulfurization treatment as necessary, and then subjected to decarburization refining in a converter.

上記の操業において、使用する炭材１５及び鉄源１６は、第１の形態例に準じる。また、炭材１５による高炭素溶鉄の硫黄濃度の上昇を抑制して、精錬終了時の高炭素溶鉄の硫黄濃度を許容最大硫黄濃度ｃ以下に制御する場合には、第１の形態例で説明したように、（１）式を用いてバイオマス由来の炭材１５の総添加量Ｘを設定する。   In the above operation, the carbon material 15 and the iron source 16 to be used conform to the first embodiment. Moreover, when suppressing the raise of the sulfur concentration of the high carbon molten iron by the carbon | charcoal material 15 and controlling the sulfur concentration of the high carbon molten iron at the time of completion | finish of refining to below the permissible maximum sulfur concentration c, it demonstrates by the 1st form example. As described above, the total addition amount X of the biomass-derived carbon material 15 is set using the equation (1).

尚、図２に示すアーク炉は、直流式アーク炉であるが、交流式アーク炉を用いても全く支障なく本発明を適用することができる。また、加炭の方法は、ランスからの上吹き投射で実施しているが、上方からの浴中へのインジェクションでも構わず、また、炉底に専用のノズルを埋設して、底吹きインジェクションでも構わない。   The arc furnace shown in FIG. 2 is a DC arc furnace, but the present invention can be applied without any problem even if an AC arc furnace is used. The carburizing method is carried out by top blowing projection from the lance, but it may be injection from above into the bath, or a dedicated nozzle is buried in the bottom of the furnace, and bottom blowing injection is also possible. I do not care.

以上説明したように、本発明によれば、主原料として鉄スクラップ１４及び溶銑１２を使用し、上底吹き転炉型の精錬炉或いはアーク炉を用いて高炭素溶鉄を製造する際に、熱源並びに加炭材としてカーボンニュートラルであるバイオマス由来の炭材を使用するので、バイオマス由来の炭材の使用比率に応じて、熱源の燃焼による温室効果ガスの発生量を削減することが実現される。また、硫黄濃度が０．１０質量％以下のバイオマス由来の炭材を使用した場合には、炭材から高炭素溶鉄への硫黄の混入を抑制することができ、製造した高炭素溶鉄への脱硫処理を省略することができるとともに、大量のバイオマス由来の炭材の使用が可能となり、硫黄混入に起因する熱源不足が解消され、鉄スクラップ１４の配合比率を高めることができ、高炭素溶鉄の生産量を増加させることが可能となる。   As described above, according to the present invention, when iron scrap 14 and hot metal 12 are used as main raw materials and a high carbon molten iron is produced using an upper bottom blown converter type refining furnace or an arc furnace, Moreover, since the carbon-derived carbonaceous material that is carbon neutral is used as the carburized material, it is possible to reduce the amount of greenhouse gas generated by combustion of the heat source according to the use ratio of the biomass-derived carbonaceous material. Moreover, when a biomass-derived carbon material having a sulfur concentration of 0.10% by mass or less is used, mixing of sulfur from the carbon material into the high-carbon molten iron can be suppressed, and desulfurization to the produced high-carbon molten iron is achieved. The treatment can be omitted and a large amount of biomass-derived charcoal can be used, the shortage of heat source due to sulfur contamination can be eliminated, the blending ratio of iron scrap 14 can be increased, and high carbon molten iron can be produced. The amount can be increased.

図１に示す転炉型精錬炉設備における本発明の実施例を以下に説明する。   An embodiment of the present invention in the converter type refining furnace facility shown in FIG. 1 will be described below.

使用した上底吹き転炉型の精錬炉は、炉容量が１チャージ（以下、「ｃｈ」と記す）約２５０トンで、底吹きガスは攪拌用としてＡｒガスを用いた。本実施例における操業条件及び代表的な溶銑成分の例を表１に示す。溶銑は機械攪拌式脱硫装置を用い、脱硫処理を施してある。鉄スクラップとしては、製鉄所で発生する鉄スクラップ（鋳片や鋼板のクロップ屑など）を使用した。   The top bottom blowing converter type refining furnace used had a furnace capacity of about 250 tons (hereinafter referred to as “ch”), and Ar gas was used as the bottom blowing gas for stirring. Table 1 shows examples of operating conditions and typical hot metal components in this example. The hot metal was desulfurized using a mechanical stirring desulfurization apparatus. As the iron scrap, iron scrap (slabs, steel plate crop scraps, etc.) generated at steelworks was used.

Figure 2013136799
Figure 2013136799

尚、本発明の効果を理解し易くするために、表１に示すように、操業条件のうちの溶銑使用量を１７０トン、装入する溶銑の温度を１３３０℃、出湯時の高炭素溶鉄の温度を１４００℃の一定の条件とし、更に、造滓材装入量も一定の条件とした。   In addition, in order to make it easy to understand the effect of the present invention, as shown in Table 1, the amount of hot metal used in the operating conditions is 170 tons, the temperature of the hot metal to be charged is 1330 ° C., and the high carbon molten iron at the time of tapping is used. The temperature was set to a constant condition of 1400 ° C., and the slagging material charging amount was also set to a constant condition.

使用したバイオマス炭は、硫黄含有量が０．０５質量％であるパームヤシ殻由来のバイオマス炭（以下、「バイオマス炭Ａ」と記す）、硫黄含有量が０．０７質量％であるパームヤシ空果房由来のバイオマス炭（以下、「バイオマス炭Ｂ」と記す）、硫黄含有量が０．１０質量％であるパームヤシ幹由来のバイオマス炭（以下、「バイオマス炭Ｃ」と記す）の３種類を用いた。また、一部の本発明例ではコークス（硫黄含有量＝０．５０質量％）も併用した。   The used biomass charcoal is palm palm shell derived biomass charcoal having a sulfur content of 0.05% by mass (hereinafter referred to as “biomass charcoal A”), and palm palm empty fruit bunch having a sulfur content of 0.07% by mass. Three types of biomass charcoal derived from biomass (hereinafter referred to as “biomass charcoal B”) and biomass charcoal derived from palm palm having a sulfur content of 0.10% by mass (hereinafter referred to as “biomass charcoal C”) were used. . In some examples of the present invention, coke (sulfur content = 0.50 mass%) was also used.

溶銑及び鉄スクラップの硫黄濃度の加重平均値ｂと、精錬終了時の高炭素溶鉄の許容最大硫黄濃度ｃとの差、即ち、精錬中に炭材投入により上昇しても許容できる硫黄量の最大値に基づいて炭材の添加量を決定した。そして、この炭材添加量に応じて鉄スクラップの配合量を決定した。つまり、鉄スクラップの配合量を炭材添加量から定まる最大値に設定した。これは、比較例１も同様である。   Difference between weighted average value b of sulfur concentration of hot metal and iron scrap and allowable maximum sulfur concentration c of high carbon molten iron at the end of refining, that is, the maximum amount of sulfur that can be tolerated even if it rises by charging carbon during refining The amount of carbon material added was determined based on the value. And the compounding quantity of the iron scrap was determined according to this carbon material addition amount. That is, the amount of iron scrap was set to the maximum value determined from the amount of carbonaceous material added. The same applies to Comparative Example 1.

但し、本発明例１では、硫黄濃度から求められる炭材添加の上限値とは関係なく、炭材の添加量を比較例１の使用量に一致させた。因みに、比較例１は、炭材としてコークス（硫黄濃度＝０．５０質量％）を使用し、コークスによる硫黄濃度の上昇量が許容最大硫黄濃度ｃとなる５００kg/chのコークスを添加し、この５００kg/chのコークスの添加によって、２０トンの鉄スクラップを配合した操業である（鉄スクラップ配合比率＝１０．５質量％）。表２に、本発明例１〜１０及び比較例１の操業条件及び操業結果を示す。   However, in Invention Example 1, the amount of carbon material added was matched to the amount used in Comparative Example 1 regardless of the upper limit value of the carbon material addition obtained from the sulfur concentration. Incidentally, in Comparative Example 1, coke (sulfur concentration = 0.50% by mass) is used as a carbonaceous material, and 500 kg / ch coke in which the amount of increase in sulfur concentration due to coke becomes an allowable maximum sulfur concentration c is added. This is an operation in which 20 tons of iron scrap is blended by adding 500 kg / ch coke (iron scrap blending ratio = 10.5% by mass). Table 2 shows the operation conditions and operation results of Examples 1 to 10 of the present invention and Comparative Example 1.

Figure 2013136799
Figure 2013136799

炭材の燃焼によるＣＯ2ガスの発生量は、下記の（２）式の化学反応式を用いて算出した。
Ｃ＋Ｏ2＝ＣＯ2 …（２）
（２）式によれば、コークス（炭素分＝８６質量％）１ｋｇあたり３．１５ｋｇのＣＯ2ガスが発生し、比較例１では約１５７７kg/chのＣＯ2ガスが発生した。 The amount of CO 2 gas generated by the combustion of the carbonaceous material was calculated using the following chemical reaction formula (2).
C + O 2 = CO 2 (2)
According to the formula (2), 3.15 kg of CO 2 gas was generated per 1 kg of coke (carbon content = 86 mass%), and about 1577 kg / ch of CO 2 gas was generated in Comparative Example 1.

本発明例１は、コークスをバイオマス炭Ａに全量置き換えて試験を実施した。本発明例１では、コークスをバイオマス炭Ａに全量置き換えることで、炭材燃焼による化石燃料由来のＣＯ2ガス排出量はゼロとなり、温室効果ガスの発生量を削減することができた。本発明例１は、比較例１と炭材の添加量が同一であり、鉄スクラップの使用量は同一であった。また、炭材からの硫黄の混入は全く問題にならなかった。 Inventive Example 1 was tested by replacing all the coke with biomass coal A. In Example 1 of the present invention, by replacing the entire amount of coke with biomass coal A, the amount of CO 2 gas derived from fossil fuel by combustion of carbonaceous materials became zero, and the amount of greenhouse gas generated could be reduced. Invention Example 1 had the same amount of carbonaceous material as Comparative Example 1 and the same amount of iron scrap used. Moreover, the mixing of sulfur from the charcoal did not cause any problems.

本発明例２〜７では、使用したバイオマス炭の硫黄含有量がコークスよりも低くなった分、許容硫黄濃度の上限までバイオマス炭の添加量を増加させ、それに伴って鉄スクラップの使用量も上限まで増加させた。尚、炭材の添加量が増加した本発明例２〜１０では、増加した炭材の添加量１ｋｇあたり約０．８Ｎｍ3の酸素ガスを増加させて試験した。 In Examples 2-7 of the present invention, the sulfur content of the used biomass coal is lower than that of coke, so the amount of biomass coal added is increased to the upper limit of the allowable sulfur concentration, and the amount of iron scrap used is also the upper limit accordingly. Increased to. In Examples 2 to 10 of the present invention in which the amount of carbon material added was increased, oxygen gas of about 0.8 Nm 3 was increased per kg of the increased amount of carbon material.

０．００１質量％の許容硫黄濃度上昇の上限に対して、本発明例２では、バイオマス炭Ａを５０００kg/ch添加し、比較例１と比較して鉄スクラップ使用量を１２．５t/ch増加させることができ、本発明例３では、バイオマス炭Ｂを３５７１kg/ch添加し、比較例１と比較して鉄スクラップ使用量を８．９t/ch増加させることができ、本発明例４では、バイオマス炭Ｃを２５００kg/ch添加し、比較例１と比較して鉄スクラップ使用量を６．３t/ch増加させることができた。   In the example 2 of the present invention, the biomass coal A is added at 5000 kg / ch to the upper limit of the allowable sulfur concentration increase of 0.001% by mass, and the amount of iron scrap used is increased by 12.5 t / ch compared with the comparative example 1. In Invention Example 3, 3571 kg / ch of biomass charcoal B is added, and the amount of iron scrap used can be increased by 8.9 t / ch compared to Comparative Example 1. In Invention Example 4, By adding 2500 kg / ch of biomass charcoal C, the amount of iron scrap used could be increased by 6.3 t / ch compared to Comparative Example 1.

また、０．００２質量％の許容硫黄濃度上昇の上限に対して、本発明例５では、バイオマス炭Ａを１００００kg/ch添加し、比較例１と比較して鉄スクラップ使用量を２５．０t/ch増加させることができ、本発明例６では、バイオマス炭Ｂを７１４３kg/ch添加し、比較例１と比較して鉄スクラップ使用量を１７．９t/ch増加させることができ、本発明例７では、バイオマス炭Ｃを５０００kg/ch添加し、比較例１と比較して鉄スクラップ使用量を１２．５t/ch増加させることができた。   Moreover, in the example 5 of this invention with respect to the upper limit of the allowable sulfur concentration increase of 0.002 mass%, biomass coal A is added 10000 kg / ch, and compared with the comparative example 1, the amount of iron scrap used is 25.0 t / In Example 6 of the present invention, 7143 kg / ch of biomass coal B was added, and the amount of iron scrap used could be increased by 17.9 t / ch compared to Comparative Example 1, and Example 7 of the present invention Then, biomass coal C was added at 5000 kg / ch, and the amount of iron scrap used could be increased by 12.5 t / ch compared with Comparative Example 1.

本発明例２〜７では、コークスをバイオマス炭に全量置き換えることで、炭材燃焼による化石燃料由来のＣＯ2ガス排出量はゼロとなり、温暖化防止の効果が発揮されるとともに、鉄スクラップ使用量の増加により生産量を増加させることができた。 In the present invention examples 2 to 7, by replacing the entire amount of coke with biomass charcoal, the amount of CO 2 gas derived from fossil fuel by combustion of carbonaceous materials becomes zero, and the effect of preventing global warming is exhibited, and the amount of iron scrap used It was possible to increase production by increasing

本発明例８〜１０では、コークスの一部をバイオマス炭に置き換えて試験を実施した。コークスとバイオマス炭の使用比率は、高炭素溶鉄の硫黄濃度規制、在庫、環境対策などにより変動させることができる。   In Examples 8 to 10 of the present invention, a test was performed by replacing part of coke with biomass charcoal. The use ratio of coke and biomass charcoal can be varied according to sulfur concentration regulations, inventory, environmental measures, etc. of high carbon molten iron.

本発明例８では、コークス２５０kg/ch、バイオマス炭Ａを２５００kg/ch添加し、比較例１と比較して炭材による化石燃料由来のＣＯ2ガス排出量を半分にすることができ、更に、鉄スクラップ使用量を６．９t/ch増加させることができた。本発明例９では、コークス２５０kg/ch、バイオマス炭Ｂを１７８６kg/ch添加し、比較例１と比較して炭材による化石燃料由来のＣＯ2ガス排出量を半分にすることができ、更に、鉄スクラップ使用量を５．０t/ch増加させることができた。本発明例１０では、コークス２５０kg/ch、バイオマス炭Ｃを１２５０kg/ch添加し、比較例１と比較して炭材による化石燃料由来のＣＯ2ガス排出量を半分にすることができ、更に、鉄スクラップ使用量を３．８t/ch増加させることができた。 In the present invention example 8, coke 250 kg / ch, biomass coal A 2500 kg / ch addition, CO 2 gas emission amount derived from fossil fuel by carbon material can be halved compared with Comparative Example 1, The amount of iron scrap used was increased by 6.9 t / ch. In Example 9 of the present invention, coke 250 kg / ch and biomass coal B 1786 kg / ch were added, and the amount of CO 2 gas derived from fossil fuel derived from charcoal can be halved compared to Comparative Example 1, The amount of iron scrap used could be increased by 5.0 t / ch. In the present invention example 10, coke 250 kg / ch, biomass coal C 1250 kg / ch addition, CO 2 gas emission amount derived from fossil fuel by carbon material can be halved compared with Comparative Example 1, The amount of iron scrap used could be increased by 3.8 t / ch.

実施例１における本発明例２の条件において、バイオマス炭Ａの添加量を５０００kg/chとしたまま、鉄スクラップの使用増加量を１２．５t/chから１０．５t/chに変更し、余剰の熱源に対して炉上から鉄源を投入し、本発明例１１〜１５を行った。鉄源としては、製鉄ダストの１種である転炉集塵ダスト（「ＯＧダスト」ともいう）、鉄鉱石、鉄鉱石の焼結鉱紛、ミルスケール及び機械工場で発生する鋼の切削屑を使用した。   In the condition of Example 1 of the present invention in Example 1, the amount of increase in the amount of iron scrap used was changed from 12.5 t / ch to 10.5 t / ch while the addition amount of biomass coal A was 5000 kg / ch, and the surplus The iron source was thrown in from the furnace with respect to the heat source, and this invention example 11-15 was performed. Iron sources include converter dust collection dust (also called “OG dust”), iron ore, sintered ore of iron ore, mill scale, and steel cutting waste generated at machine shops. used.

表３に、本発明例１１〜１５の操業条件及び操業結果を示す。尚、表３に示す鉄歩留向上とは、鉄源を添加しない場合に比較して、炉上から添加した冷却材が還元され、鉄となった量を示したものである。   Table 3 shows the operation conditions and operation results of Examples 11 to 15 of the present invention. In addition, the iron yield improvement shown in Table 3 shows the amount of the coolant added from the furnace reduced to iron, compared to the case where no iron source is added.

Figure 2013136799
Figure 2013136799

鋼の切削屑を添加した本発明例１５では、切削屑は還元する必要がなく、高い鉄歩留りの向上が得られたが、鉄酸化物が主体である鉄源を使用した本発明例１１〜１４においても鉄歩留りの向上が得られた。つまり、鉄酸化物が主体である鉄源であっても、鉄歩留り向上の効果があり、生産量を増加させることが確認できた。つまり、熱源の増加分を鉄スクラップだけではなく、炉上からの鉄源に置き換えても問題はなく、歩留向上の効果があり、生産量を増加させることができた。   In Invention Example 15 to which steel cutting waste was added, the cutting waste did not need to be reduced, and high iron yield was improved, but Invention Examples 11 to 11 using an iron source mainly composed of iron oxide were obtained. 14 also improved the iron yield. That is, it was confirmed that even an iron source mainly composed of iron oxide has an effect of improving the iron yield and increases the production amount. In other words, there was no problem even if the increase in the heat source was replaced not only with iron scrap but also with the iron source from the furnace, yielding was improved, and the production volume could be increased.

本発明においては、カーボンニュートラルであるバイオマス炭を化石燃料からなる従来の炭材の一部または全部と置き換え使用することで、温室効果ガスの発生量を削減することができ、更に、従来の炭材よりも硫黄含有量が低いバイオマス炭を使用することで、高炭素溶鉄の硫黄濃度規制に起因する熱源不足を解消し、従来よりも多くの鉄スクラップや炉上からの鉄源を使用することができ、生産量を増加させることができた。尚、従来技術である比較例１では、炭材としてコークスを用いているが、無煙炭、黒鉛などの炭材を使用しても構わず、これらの無煙炭、黒鉛などの炭材をバイオマス炭に置き換えても何ら問題はない。   In the present invention, the carbon-neutral biomass charcoal is replaced with a part or all of the conventional charcoal made of fossil fuel, so that the amount of greenhouse gas generated can be reduced. By using biomass charcoal with a sulfur content lower than that of the lumber, the shortage of heat source due to the sulfur concentration regulation of high-carbon molten iron is eliminated, and more iron scrap and iron sources from the furnace than before are used. Was able to increase production. In Comparative Example 1, which is the prior art, coke is used as the charcoal, but charcoal such as anthracite and graphite may be used, and the carbon such as anthracite and graphite is replaced with biomass charcoal. There is no problem.

１ 転炉型精錬炉設備
２ 精錬炉本体
３ 炉口
４ 上吹き酸素ランス
５ 底吹き羽口
６ ガス導入管
７ 出湯口
８ ダクト
９ ホッパー
１０ 切り出し装置
１１ シュート
１２ 溶銑
１３ 溶融スラグ
１４ 鉄スクラップ
１５ 炭材
１６ 鉄源
２１ 直流式アーク炉
２２ 溶解室
２３ 炉蓋
２４ 上部電極
２５ 炉底電極
２６ 溶銑装入樋
２７ 装入鍋
２８ クレーン
２９ 出湯口
３０ 酸素ガス供給ランス
３１ 炭材供給ランス
３２ 原料投入シュート
３３ アーク DESCRIPTION OF SYMBOLS 1 Converter type refining furnace equipment 2 Refining furnace main body 3 Furnace opening 4 Top blowing oxygen lance 5 Bottom blowing tuyere 6 Gas introduction pipe 7 Outlet 8 Duct 9 Hopper 10 Cutting device 11 Chute 12 Hot metal 13 Molten slag 14 Iron scrap 15 Charcoal Material 16 Iron source 21 DC arc furnace 22 Melting chamber 23 Furnace lid 24 Upper electrode 25 Furnace bottom electrode 26 Hot metal charging rod 27 Charging pan 28 Crane 29 Hot water outlet 30 Oxygen gas supply lance 31 Carbon material supply lance 32 Raw material charging chute 33 arc

Claims (7)

鉄スクラップ及び溶銑を鉄源として精錬炉内に装入し、次いで、該精錬炉内に酸素ガスを供給し、前記精錬炉内の前記鉄スクラップを精錬炉内に供給した炭材の前記酸素ガスによる燃焼熱及び前記溶銑の顕熱によって溶解するとともに、前記鉄スクラップを前記炭材及び前記溶銑によって加炭し、炭素濃度が３．０質量％以上の高炭素溶鉄を前記精錬炉内で製造する方法であって、前記炭材の一部または全部としてバイオマス由来の炭材を使用することを特徴とする、鉄スクラップを用いた高炭素溶鉄の製造方法。   Charging iron scrap and hot metal into the smelting furnace as an iron source, then supplying oxygen gas into the smelting furnace, and the oxygen gas of the carbonaceous material that supplied the iron scrap in the smelting furnace into the smelting furnace The high-carbon molten iron having a carbon concentration of 3.0% by mass or more is produced in the smelting furnace while being melted by the combustion heat of the molten iron and the sensible heat of the molten iron, and carburizing the iron scrap with the carbonaceous material and the molten iron. It is a method, Comprising: The carbon material derived from biomass is used as a part or all of the said carbon material, The manufacturing method of the high carbon molten iron using an iron scrap characterized by the above-mentioned. 前記精錬炉が、前記酸素ガスを上吹き供給する上底吹き転炉型の精錬炉であることを特徴とする、請求項１に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。   2. The method for producing high-carbon molten iron using iron scrap according to claim 1, wherein the refining furnace is a top-bottom-blown converter type refining furnace that blows up the oxygen gas. 3. 前記精錬炉が、アーク炉であって、前記炭材の燃焼熱及び前記溶銑の顕熱に加えて発生するアークの熱で、前記鉄スクラップを溶解することを特徴とする、請求項１に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。   The said smelting furnace is an arc furnace, The said iron scrap is melt | dissolved with the heat of the arc generated in addition to the combustion heat of the said carbonaceous material, and the sensible heat of the said hot metal, The said scraps are characterized by the above-mentioned. Of high-carbon molten iron using steel scrap. 前記バイオマス由来の炭材の硫黄濃度が０．１０質量％以下であることを特徴とする、請求項１ないし請求項３の何れか１項に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。   The method for producing high-carbon molten iron using iron scrap according to any one of claims 1 to 3, wherein the biomass-derived carbonaceous material has a sulfur concentration of 0.10 mass% or less. . 前記バイオマス由来の炭材の総添加量をＸ（kg-炭材/t-溶鉄）、該炭材の硫黄濃度をａ（質量％）、精錬前の溶銑及び鉄スクラップの硫黄濃度の加重平均値をｂ（質量％）、精錬終了時の高炭素溶鉄の許容最大硫黄濃度をｃ（質量％）としたとき、前記炭材の総添加量Ｘを下記の（１）式で求められる値とし、この炭材の総添加量Ｘに基づいて前記鉄スクラップの装入量を決定することを特徴とする、請求項１ないし請求項４の何れか１項に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。
Ｘ＝［（ｃ−ｂ）／ａ］×１０００ …（１） X (kg-charcoal material / t-molten iron) is the total amount of carbonaceous material derived from biomass, the sulfur concentration of the carbonaceous material is a (mass%), the weighted average value of the hot metal before refining and the sulfur concentration of iron scrap And b (mass%), and when the allowable maximum sulfur concentration of high carbon molten iron at the end of refining is c (mass%), the total addition amount X of the carbonaceous material is a value determined by the following equation (1), The high carbon molten iron using the iron scrap according to any one of claims 1 to 4, wherein a charging amount of the iron scrap is determined based on a total amount X of the carbon material. Manufacturing method.
X = [(c−b) / a] × 1000 (1) 前記バイオマス由来の炭材が、パームヤシ殻由来のバイオマス炭、パームヤシ空果房由来のバイオマス炭、パームヤシ幹由来のバイオマス炭のうちの何れか１種または２種以上であることを特徴とする、請求項１ないし請求項５の何れか１項に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。   The biomass-derived charcoal material is any one or more of biomass charcoal derived from palm coconut shell, biomass charcoal derived from palm palm empty fruit bunches, and biomass charcoal derived from palm palm trunk, The manufacturing method of the high carbon molten iron using the iron scrap of any one of Claims 1 thru | or 5. 前記精錬炉内への酸素ガスの供給中に、鉄鉱石、鉄鉱石の焼結鉱、ミルスケール、製鉄ダスト、磁選屑、鋼の切削屑からなる鉄源のうちの何れか１種または２種以上の鉄源を前記精錬炉内に投入することを特徴とする、請求項１ないし請求項６の何れか１項に記載の鉄スクラップを用いた高炭素溶鉄の製造方法。   During the supply of oxygen gas into the smelting furnace, any one or two of iron sources comprising iron ore, iron ore sintered ore, mill scale, iron making dust, magnetic separation scrap, and steel cutting scrap The method for producing high-carbon molten iron using iron scrap according to any one of claims 1 to 6, wherein the iron source is put into the smelting furnace.
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