JP6710564B2 - Electric furnace refining method - Google Patents
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- JP6710564B2 JP6710564B2 JP2016075889A JP2016075889A JP6710564B2 JP 6710564 B2 JP6710564 B2 JP 6710564B2 JP 2016075889 A JP2016075889 A JP 2016075889A JP 2016075889 A JP2016075889 A JP 2016075889A JP 6710564 B2 JP6710564 B2 JP 6710564B2
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- 238000007670 refining Methods 0.000 title claims description 61
- 238000000034 method Methods 0.000 title claims description 21
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 158
- 239000002893 slag Substances 0.000 claims description 142
- 239000000463 material Substances 0.000 claims description 88
- 229910052742 iron Inorganic materials 0.000 claims description 78
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 58
- 238000005255 carburizing Methods 0.000 claims description 55
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 20
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 20
- 239000000203 mixture Substances 0.000 claims description 12
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 claims description 8
- 239000000843 powder Substances 0.000 claims description 8
- 239000011230 binding agent Substances 0.000 claims description 6
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 38
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 36
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 18
- 235000012255 calcium oxide Nutrition 0.000 description 18
- 239000000292 calcium oxide Substances 0.000 description 18
- 229910052760 oxygen Inorganic materials 0.000 description 18
- 239000001301 oxygen Substances 0.000 description 18
- 229910052799 carbon Inorganic materials 0.000 description 17
- 102100032369 Coiled-coil domain-containing protein 112 Human genes 0.000 description 16
- 101100059310 Homo sapiens CCDC112 gene Proteins 0.000 description 16
- 239000004484 Briquette Substances 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 9
- 102100036763 Extended synaptotagmin-1 Human genes 0.000 description 5
- 101000851525 Homo sapiens Extended synaptotagmin-1 Proteins 0.000 description 5
- 239000003575 carbonaceous material Substances 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000007664 blowing Methods 0.000 description 4
- 238000003763 carbonization Methods 0.000 description 4
- 239000000571 coke Substances 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 229910000805 Pig iron Inorganic materials 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000005422 blasting Methods 0.000 description 2
- 235000013312 flour Nutrition 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 231100000681 Certain safety factor Toxicity 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000011269 tar Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Description
本発明は、スラグの密度よりも見かけ密度が高い加炭材を用いた電気炉精錬方法に関する。 The present invention relates to an electric furnace refining method using a carburizing material having an apparent density higher than that of slag.
電気炉精錬においては、アーク電極によって形成されるアークプラズマを用いて、主原料の鉄屑および造滓材を溶解しつつ、酸素ランスからＯ２ガスとともに、コークス粉等の加炭材を電気炉内の溶鉄に供給する。電気炉に供給された加炭材は、燃焼することによって炉内の溶鉄および溶鉄の表面に生成した溶融スラグへ熱付加する。また、加炭材は、溶鉄表面に生成したスラグ中の酸化鉄等の酸化物の還元材、さらには、電気炉内の溶鉄の加炭材として作用する。 In electric furnace refining, an arc plasma formed by an arc electrode is used to dissolve iron scraps and slag material, which are main raw materials, and an oxygen lance to feed O 2 gas together with a carburizing material such as coke powder into an electric furnace. To supply molten iron inside. The carburizing material supplied to the electric furnace adds heat to the molten iron in the furnace and the molten slag generated on the surface of the molten iron by burning. Further, the carburizing material acts as a reducing agent for oxides such as iron oxide in the slag formed on the surface of the molten iron, and further as a carburizing material for the molten iron in the electric furnace.
従来、電気炉精錬で用いられている加炭材としては、小塊コークス、コークス粉、ＣＤＱ粉（コークス消火設備捕集粉）、ＣＤＱ粉のブリケットおよび鉄粉含有ＣＤＱ粉のブリケット等が知られている。これらは酸化物の還元、ＣＯガスやＣＯ２ガスへの燃焼および溶鋼への加炭等の反応へ寄与しやすく、また、簡易な設備で製造できることから、電気炉精錬に広く用いられている。例えば、特許文献１には、電気炉ダストと粉粒状炭材とを用いた電気炉用加炭材が開示されている。 Conventionally, as carburizing materials used in electric furnace refining, small coke, coke powder, CDQ powder (coke extinguishing equipment collection powder), briquette of CDQ powder and briquette of iron powder-containing CDQ powder are known. ing. These are widely used in electric furnace refining because they easily contribute to the reactions such as reduction of oxides, combustion into CO gas or CO 2 gas, and carburization into molten steel, and they can be produced with simple equipment. For example, Patent Document 1 discloses a carburizing material for an electric furnace, which uses electric furnace dust and powdery carbonaceous material.
しかしながら、従来から用いられている加炭材および特許文献１に開示されている加炭材の見かけ密度は、溶鉄の表面に生成した溶融スラグの密度より小さい。このため、加炭材を電気炉内に投入しても、溶融スラグ内で浮上してしまい溶鉄に到達できず、その後、溶融スラグとともに排滓されるので、溶融スラグの鉄濃度を低下できない、という課題があった。本発明は、従来技術が抱える上記課題を鑑みてなされたものであり、電気炉精錬終了後における溶融スラグの鉄濃度を含む成分濃度から算出される計算密度を所定の範囲内にすることで、鉄濃度を従来よりも低い濃度に抑えた電気炉精錬方法を提供することを目的とする。 However, the apparent density of the conventionally used carburizing material and the carburizing material disclosed in Patent Document 1 is smaller than the density of the molten slag generated on the surface of the molten iron. Therefore, even if the carburizing material is put into the electric furnace, the molten iron cannot be reached because it floats in the molten slag, and is then discharged together with the molten slag, so that the iron concentration of the molten slag cannot be reduced, There was a problem called. The present invention has been made in view of the above problems that the conventional art has, by making the calculated density calculated from the component concentration including the iron concentration of the molten slag after the completion of the electric furnace refining within a predetermined range, An object of the present invention is to provide an electric furnace refining method in which the iron concentration is suppressed to a lower concentration than before.
このような課題を解決するための本発明の特徴は、以下の通りである。
［１］炭材粉と、バインダーと、鉄、鉄酸化物、マンガンおよびマンガン酸化物の少なくとも１つと、を含む加炭材を溶鉄に投入する電気炉精錬方法であって、電気炉精錬におけるスラグの密度よりも見かけ密度が高い前記加炭材を溶鉄に投入し、電気炉精錬終了後の前記スラグの組成が下記の数式（１）を満足することを特徴とする電気炉精錬方法。
３６００≦｛（ＦｅＯ質量％）＋（ＳｉＯ２質量％）＋（ＣａＯ質量％）＋（Ａｌ２Ｏ３質量％）＋（ＭｇＯ質量％）＋（ＭｎＯ質量％）｝／｛（ＦｅＯ質量％）／５７４０＋（ＳｉＯ２質量％）／２７００＋（ＣａＯ質量％）／３２００＋（Ａｌ２Ｏ３質量％）／４０００＋（ＭｇＯ質量％）／３６００＋（ＭｎＯ質量％）／５４００｝≦４２１５・・・数式（１）
但し、上記数式（１）において、（ＦｅＯ質量％）は、前記スラグ中のＦｅＯ濃度を表し、（ＳｉＯ２質量％）は、前記スラグ中のＳｉＯ２濃度を表し、（ＣａＯ質量％）は、前記スラグ中のＣａＯ濃度を表し、（Ａｌ２Ｏ３質量％）は、前記スラグ中のＡｌ２Ｏ３濃度を表し、（ＭｇＯ質量％）は、前記スラグ中のＭｇＯ濃度を表し、（ＭｎＯ質量％）は、前記スラグ中のＭｎＯ濃度を表す。
［２］炭材粉と、バインダーと、鉄、鉄酸化物、マンガンおよびマンガン酸化物の少なくとも１つと、を含む加炭材を溶鉄に投入する電気炉精錬方法であって、前記加炭材は、電気炉精錬におけるスラグの密度よりも見かけ密度が高いことを特徴とする電気炉精錬方法。
［３］前記加炭材の見かけ密度は、下記の数式（２）を満足することを特徴とする［２］に記載の電気炉精錬方法。
Ｙ＞｛（ＦｅＯ質量％）＋（ＳｉＯ２質量％）＋（ＣａＯ質量％）＋（Ａｌ２Ｏ３質量％）＋（ＭｇＯ質量％）＋（ＭｎＯ質量％）｝／｛（ＦｅＯ質量％）／５７４０＋（ＳｉＯ２質量％）／２７００＋（ＣａＯ質量％）／３２００＋（Ａｌ２Ｏ３質量％）／４０００＋（ＭｇＯ質量％）／３６００＋（ＭｎＯ質量％）／５４００｝・・・数式（２）
但し、上記数式（２）において、Ｙは、前記加炭材の見かけ密度（ｋｇ／ｍ３）を表し、（ＦｅＯ質量％）は、前記スラグ中のＦｅＯ濃度を表し、（ＳｉＯ２質量％）は、前記スラグ中のＳｉＯ２濃度を表し、（ＣａＯ質量％）は、前記スラグ中のＣａＯ濃度を表し、（Ａｌ２Ｏ３質量％）は、前記スラグ中のＡｌ２Ｏ３濃度を表し、（ＭｇＯ質量％）は、前記スラグ中のＭｇＯ濃度を表し、（ＭｎＯ質量％）は、前記スラグ中のＭｎＯ濃度を表す。
［４］前記加炭材は、炭素分原単位で２．１ｋｇ／ｔ−溶鉄以上となるように前記溶鉄に投入される［２］または［３］に記載の電気炉精錬方法。
［５］前記加炭材は、炭素分原単位で３０．１ｋｇ／ｔ−溶鉄以下となるように前記溶鉄に投入される［２］から［４］のいずれか１つに記載の電気炉精錬方法。
［６］前記鉄および鉄酸化物として、鉄製ショットブラスト残渣および／または磁着スラグを用いることを特徴とする［２］から［５］のいずれか１つに記載の電気炉精錬方法。
The features of the present invention for solving such a problem are as follows.
[1] An electric furnace refining method in which a carburizing material containing carbonaceous material powder, a binder, and at least one of iron, iron oxide, manganese, and manganese oxide is charged into molten iron, and the slag in electric furnace refining is used. An electric furnace refining method in which the carburizing material having an apparent density higher than that of No. 1 is charged into molten iron, and the composition of the slag after completion of electric furnace refining satisfies the following mathematical formula (1).
3600≦{(FeO mass%)+(SiO 2 mass%)+(CaO mass%)+(Al 2 O 3 mass%)+(MgO mass%)+(MnO mass%)}/{(FeO mass%) /5740+(SiO 2 mass %)/2700+(CaO mass %)/3200+(Al 2 O 3 mass %)/4000+(MgO mass %)/3600+(MnO mass %)/5400}≦4215... )
However, in the above formula (1), (FeO mass%) represents the FeO concentration in the slag, (SiO 2 mass%) represents the SiO 2 concentration in the slag, and (CaO mass%) is It represents the CaO concentration in the slag, (Al 2 O 3 mass%) represents the Al 2 O 3 concentration in the slag, (MgO mass%) represents the MgO concentration in the slag, (MnO mass %) represents the MnO concentration in the slag.
[2] An electric furnace refining method of introducing a carburizing material containing carbonaceous material powder, a binder, and at least one of iron, iron oxide, manganese, and manganese oxide into molten iron, wherein the carburizing material is An electric furnace refining method characterized by having an apparent density higher than that of slag in electric furnace refining.
[3] The electric furnace refining method according to [2], wherein the apparent density of the carburized material satisfies the following mathematical expression (2).
Y>{(FeO mass%)+(SiO 2 mass%)+(CaO mass%)+(Al 2 O 3 mass%)+(MgO mass%)+(MnO mass%)}/{(FeO mass%) /5740+(SiO 2 mass%)/2700+(CaO mass%)/3200+(Al 2 O 3 mass%)/4000+(MgO mass%)/3600+(MnO mass%)/5400}... Numerical formula (2)
However, in the above formula (2), Y represents the apparent density (kg/m 3 ) of the carburized material, (FeO mass%) represents the FeO concentration in the slag, and (SiO 2 mass%) Represents the SiO 2 concentration in the slag, (CaO mass%) represents the CaO concentration in the slag, (Al 2 O 3 mass%) represents the Al 2 O 3 concentration in the slag, (MgO mass%) represents the MgO concentration in the slag, and (MnO mass%) represents the MnO concentration in the slag.
[4] The electric furnace refining method according to [2] or [3], wherein the carburizing material is added to the molten iron such that the carbon content is 2.1 kg/t-molten iron or more.
[5] The electric furnace refining according to any one of [2] to [4], wherein the carburizing material is charged into the molten iron so that the carbon content is 30.1 kg/t-molten iron or less. Method.
[6] The electric furnace refining method according to any one of [2] to [5], wherein iron shot blasting residue and/or magnetic slag is used as the iron and the iron oxide.
本発明の電気炉精錬方法を用いることで、電気炉精錬終了後における溶融スラグの鉄濃度を含む成分濃度から算出される計算密度を、３６００ｋｇ／ｍ３以上４２１５ｋｇ／ｍ３以下の範囲内に調整できる。これにより、従来よりも溶融スラグの鉄濃度を低い濃度に抑えた電気炉精錬が実現でき、電気炉精錬における鉄歩留まりを向上できる。 By using the electric furnace refining method of the present invention, the calculated density calculated from the component concentration including the iron concentration of the molten slag after the electric furnace refining is adjusted within the range of 3600 kg/m 3 or more and 4215 kg/m 3 or less. it can. As a result, electric furnace refining in which the iron concentration of the molten slag is suppressed to a lower concentration than in the past can be realized, and the iron yield in electric furnace refining can be improved.
以下、発明の実施形態を通じて本発明を説明する。図１は、本実施形態に係る電気炉精錬方法が適用される電気炉１０の一例を示す断面図である。電気炉１０は、炉本体１２と、炉蓋１４と、アーク電極１６と、バーナー１８と、シュート２０と、酸素ランス２２と、を備える。 Hereinafter, the present invention will be described through embodiments of the invention. FIG. 1 is a sectional view showing an example of an electric furnace 10 to which the electric furnace refining method according to the present embodiment is applied. The electric furnace 10 includes a furnace body 12, a furnace lid 14, an arc electrode 16, a burner 18, a chute 20, and an oxygen lance 22.
電気炉１０の炉本体１２には、まず、スクラップ等の屑鉄が生石灰等の造滓材とともに装入される。その後、アーク電極１６によって形成されるアークプラズマとバーナー１８を用いた屑鉄側面からのカッチングにより、屑鉄および造滓材が炉本体１２内で溶解される。図１は、屑鉄および造滓材が溶解され、炉本体１２において溶鉄２４の上表面に溶融スラグ２６が形成された状態を示している。なお、溶融スラグ２６は、前チャージの溶融スラグの一部を含む。屑鉄および造滓材が溶解された後、不図示の炉頂ホッパに貯留された加炭材２８が、シュート２０を介して段階的に炉本体１２へ投入される。 First, scrap iron such as scrap is charged into the furnace body 12 of the electric furnace 10 together with slag material such as quick lime. After that, the scrap iron and the slag material are melted in the furnace body 12 by the arc plasma formed by the arc electrode 16 and the scraping from the scrap iron side surface using the burner 18. FIG. 1 shows a state in which the scrap iron and the slag material are melted and the molten slag 26 is formed on the upper surface of the molten iron 24 in the furnace body 12. The molten slag 26 includes a part of the pre-charged molten slag. After the scrap iron and the slag material are melted, the carburized material 28 stored in the furnace top hopper (not shown) is gradually charged into the furnace body 12 via the chute 20.
図２（ａ）は、溶融スラグの密度よりも見かけ密度が大きい加炭材２８の溶融スラグ内の状態を示す模式図である。図２（ｂ）は、溶融スラグの密度よりも見かけ密度が小さい加炭材３０の溶融スラグ内の状態を示す模式図である。 FIG. 2A is a schematic diagram showing a state in the molten slag of the carburized material 28 having an apparent density higher than that of the molten slag. FIG. 2B is a schematic diagram showing a state in the molten slag of the carburized material 30 having an apparent density smaller than that of the molten slag.
図２（ａ）に示した加炭材２８は、本実施形態に係る電気炉精錬方法に用いられる加炭材であり、溶融スラグ２６の密度よりも見かけ密度が大きい加炭材である。加炭材２８は、シュート２０から投入されて溶融スラグ２６に入り込む。加炭材２８の見かけ密度は、溶融スラグ２６の密度よりも大きいので、溶融スラグ２６からの浮力よりも加炭材２８にかかる重力の方が大きくなる。このため、加炭材２８は、図２（ａ）に示すように溶融スラグ２６中を沈降する。これにより、加炭材２８のほとんどが溶鉄２４に到達でき、この結果、加炭材２８の着炭効率は大きく向上する。なお、本実施形態において、着炭効率とは、投入した加炭材における炭素質量に対して溶鉄の炭素濃度向上に寄与した炭素質量の割合（質量％）をいう。 The carburizing material 28 shown in FIG. 2A is a carburizing material used in the electric furnace refining method according to this embodiment, and has a larger apparent density than the density of the molten slag 26. The carburizing material 28 is introduced from the chute 20 and enters the molten slag 26. Since the apparent density of the carburized material 28 is higher than the density of the molten slag 26, the gravity applied to the carburized material 28 is larger than the buoyancy from the molten slag 26. Therefore, the carburized material 28 settles in the molten slag 26 as shown in FIG. As a result, most of the carburized material 28 can reach the molten iron 24, and as a result, the carburization efficiency of the carburized material 28 is greatly improved. In the present embodiment, the carburization efficiency means the ratio (mass %) of the carbon mass that contributes to the improvement of the carbon concentration of the molten iron to the carbon mass of the added carburizing material.
一方、図２（ｂ）に示した加炭材３０は、溶融スラグ２６の密度よりも見かけ密度が小さい加炭材である。加炭材３０も、加炭材２８と同様に、シュート２０から投入されて溶融スラグ２６に入り込む。しかしながら、加炭材３０の見かけ密度は溶融スラグ２６の密度よりも小さいので、図２（ｂ）に示すように、加炭材３０は、溶融スラグ２６の浮力によって溶融スラグ２６内で浮上する。このため、加炭材３０のほとんどが溶鉄２４に到達できず、溶融スラグ２６の上表面を漂った後に、溶融スラグ２６とともに系外に排滓される。このため、加炭材３０の着炭効率は低下する。 On the other hand, the carburized material 30 shown in FIG. 2B is a carburized material having an apparent density lower than that of the molten slag 26. Similarly to the carburizing material 28, the carburizing material 30 is also charged from the chute 20 and enters the molten slag 26. However, since the apparent density of the carburized material 30 is lower than the density of the molten slag 26, the carburized material 30 floats in the molten slag 26 due to the buoyancy of the molten slag 26, as shown in FIG. Therefore, most of the carburized material 30 cannot reach the molten iron 24, and after drifting on the upper surface of the molten slag 26, it is discharged outside the system together with the molten slag 26. Therefore, the carburizing efficiency of the carburizing material 30 is reduced.
本実施形態における加炭材２８は、溶融スラグ２６の計算密度よりも見かけ密度が高い。電気炉精錬における溶融スラグ２６の計算密度Ｘは、その溶融スラグの各成分濃度から下記の数式（３）で算出できる。なお、計算密度Ｘとは、溶融スラグ２６の成分濃度から計算される密度をいう。 The carburized material 28 in the present embodiment has a higher apparent density than the calculated density of the molten slag 26. The calculated density X of the molten slag 26 in the electric furnace refining can be calculated by the following mathematical expression (3) from the concentration of each component of the molten slag. The calculated density X means the density calculated from the component concentration of the molten slag 26.
Ｘ＝｛（ＦｅＯ質量％）＋（ＳｉＯ２質量％）＋（ＣａＯ質量％）＋（Ａｌ２Ｏ３質量％）＋（ＭｇＯ質量％）＋（ＭｎＯ質量％）｝／｛（ＦｅＯ質量％）／５７４０＋（ＳｉＯ２質量％）／２７００＋（ＣａＯ質量％）／３２００＋（Ａｌ２Ｏ３質量％）／４０００＋（ＭｇＯ質量％）／３６００＋（ＭｎＯ質量％）／５４００｝・・・数式（３） X={(FeO mass %)+(SiO 2 mass %)+(CaO mass %)+(Al 2 O 3 mass %)+(MgO mass %)+(MnO mass %)}/{(FeO mass %) /5740+(SiO 2 mass%)/2700+(CaO mass%)/3200+(Al 2 O 3 mass%)/4000+(MgO mass%)/3600+(MnO mass%)/5400}... Numerical formula (3)
但し、上記数式（３）で、Ｘは、溶融スラグ２６の計算密度（ｋｇ／ｍ３）を表し、（ＦｅＯ質量％）は、溶融スラグ２６中のＦｅＯ濃度を表し、（ＳｉＯ２質量％）は、溶融スラグ２６中のＳｉＯ２濃度を表し、（ＣａＯ質量％）は、溶融スラグ２６中のＣａＯ濃度を表し、（Ａｌ２Ｏ３質量％）は、溶融スラグ２６中のＡｌ２Ｏ３濃度を表し、（ＭｇＯ質量％）は、溶融スラグ２６中のＭｇＯ濃度を表し、（ＭｎＯ質量％）は、溶融スラグ２６中のＭｎＯ濃度を表す。 However, in the above formula (3), X represents the calculated density (kg/m 3 ) of the molten slag 26, (FeO mass%) represents the FeO concentration in the molten slag 26, and (SiO 2 mass%) Represents the SiO 2 concentration in the molten slag 26, (CaO mass%) represents the CaO concentration in the molten slag 26, and (Al 2 O 3 mass%) represents the Al 2 O 3 concentration in the molten slag 26. , (MgO mass%) represents the MgO concentration in the molten slag 26, and (MnO mass%) represents the MnO concentration in the molten slag 26.
加炭材２８の見かけ密度は、溶融スラグ２６の計算密度よりも高いので、加炭材２８の見かけ密度Ｙは、下記の数式（２）を満足する。 Since the apparent density of the carburized material 28 is higher than the calculated density of the molten slag 26, the apparent density Y of the carburized material 28 satisfies the following mathematical expression (2).
Ｙ＞｛（ＦｅＯ質量％）＋（ＳｉＯ２質量％）＋（ＣａＯ質量％）＋（Ａｌ２Ｏ３質量％）＋（ＭｇＯ質量％）＋（ＭｎＯ質量％）｝／｛（ＦｅＯ質量％）／５７４０＋（ＳｉＯ２質量％）／２７００＋（ＣａＯ質量％）／３２００＋（Ａｌ２Ｏ３質量％）／４０００＋（ＭｇＯ質量％）／３６００＋（ＭｎＯ質量％）／５４００｝・・・数式（２） Y>{(FeO mass%)+(SiO 2 mass%)+(CaO mass%)+(Al 2 O 3 mass%)+(MgO mass%)+(MnO mass%)}/{(FeO mass%) /5740+(SiO 2 mass%)/2700+(CaO mass%)/3200+(Al 2 O 3 mass%)/4000+(MgO mass%)/3600+(MnO mass%)/5400}... Numerical formula (2)
但し、上記数式（２）において、Ｙは、加炭材２８の見かけ密度（ｋｇ／ｍ３）を示し、他は、数式（３）と同じである。 However, in the above mathematical expression (2), Y represents the apparent density (kg/m 3 ) of the carburized material 28, and the rest is the same as the mathematical expression (3).
溶融スラグ２６の初期の各成分濃度は、前チャージから持ち込まれる溶融スラグの量と、持ち込まれる溶融スラグ中の各成分濃度と、当該チャージで投入される造滓材の量とから予測できる。また、その後の溶融スラグ２６の各成分濃度の変化は、予測された初期の溶融スラグ２６の各成分濃度と、本実施形態に係る溶融スラグ２６の計算密度よりも見かけ密度の高い加炭材を用いることによる溶融スラグ２６の成分調整効果を加味して定められたターゲットとなる鋼種の成分に調整するための電気炉精錬条件と、から予測できる。そして、予測された各成分濃度の変化と上記数式（３）を用いて算出された溶融スラグ２６の計算密度の変化の推移における最も高い計算密度に一定の安全率を乗じた値よりも加炭材２８の見かけ密度が高くなるように、加炭材２８の原料の配合量を定めて製造する。 The initial concentration of each component of the molten slag 26 can be predicted from the amount of the molten slag brought in from the previous charge, the concentration of each component in the brought-in molten slag, and the amount of the slag material charged by the charge. Further, the change in the concentration of each component of the molten slag 26 after that, the predicted initial concentration of each component of the molten slag 26, and the carburized material having a higher apparent density than the calculated density of the molten slag 26 according to the present embodiment. It can be predicted from the electric furnace refining conditions for adjusting the composition of the target steel species that has been determined in consideration of the composition adjustment effect of the molten slag 26. Then, the carburization is higher than the value obtained by multiplying the highest calculated density in the transition of the predicted change in each component concentration and the change in the calculated density of the molten slag 26 calculated by using the mathematical formula (3) by a certain safety factor. The raw material of the carburizing material 28 is determined in the compounding amount so that the apparent density of the material 28 becomes high.
次に、加炭材２８の製造方法について説明する。本実施形態に係る加炭材２８は、コークス粉と、タールと、製鉄所で発生した鉄製ショットブラスト残渣または磁着スラグを含んで構成される。なお、コークス粉は、炭材粉の一例であり、タールは、バインダーの一例である。また、鉄製ショットブラスト残渣または磁着スラグは、鉄、鉄酸化物の少なくとも１つの例である。また、鉄、鉄酸化物に代えて、マンガンおよびマンガン酸化物を用いてもよい。また、磁着スラグとは、製鉄所における製鋼工程で発生したスラグを粉砕した後に磁力選別し、磁着側に選別されたスラグである。 Next, a method of manufacturing the carburized material 28 will be described. The carburized material 28 according to the present embodiment is configured to include coke powder, tar, and iron shot blast residue or magnetized slag generated in an iron mill. The coke powder is an example of carbonaceous material powder, and the tar is an example of a binder. Further, the iron shot blast residue or the magnetic slag is an example of at least one of iron and iron oxide. Further, manganese and manganese oxide may be used instead of iron and iron oxide. Further, the magnetically-adhered slag is a slag that has been magnetically sorted by crushing the slag generated in the steelmaking process in an iron mill and then sorted to the magnetically-coated side.
下記表１に加炭材２８に用いた鉄製ショットブラスト残渣および磁着スラグの組成を示す。このように、鉄および鉄酸化物として、製鉄所で発生した鉄製ショットブラスト残渣および／または磁着スラグを用いてよい。これにより、製鉄所で発生した鉄製ショットブラスト残渣や磁着スラグを加炭材２８の原料としてリサイクルできる。 Table 1 below shows the compositions of the iron shot blast residue and the magnetic slag used for the carburized material 28. Thus, iron shot blasting residue and/or magnetic slag generated in the steel mill may be used as iron and iron oxide. As a result, the iron shot blast residue and the magnetic slag generated at the steel mill can be recycled as the raw material of the carburizing material 28.
これらの原料は、加炭材２８の見かけ密度Ｙが上記数式（２）を満足するように配合され、ニーダー方式またはＫＢ方式を用いて混合され、その後、ブリケットマシンを用いて成型される。このようにして、本実施形態に係る加炭材２８が製造される。 These raw materials are blended so that the apparent density Y of the carburized material 28 satisfies the above mathematical expression (2), mixed using the kneader method or the KB method, and then molded using a briquette machine. In this way, the carburized material 28 according to the present embodiment is manufactured.
加炭材２８は、その見かけ密度が溶融スラグ２６の計算密度よりも高いので、溶融スラグ２６内を沈降して高い着炭効率で溶鉄２４に着炭する。図３は、加炭材の着炭効率を示すグラフである。図３において、「ＭＢＣ１」は、コークス粉に鉄製ショットブラスト残渣とタールとを添加して製造したメタルブリケットである。「ＭＢＣ２」は、コークス粉に磁着スラグとバインダーとを添加して製造したメタルブリケットである。「コークス粉」は、酸素ランスからインジェクションで投入したコークス粉である。また、「コークス粉ブリケット」は、コークス粉にバインダーを添加して成型したブリケットである。これらの加炭材の組成と、見かけ密度と、これらの加炭材を用いて電気炉精錬を実施した後の場合の溶融スラグの計算密度と、を表２に示す。 Since the apparent density of the carburizing material 28 is higher than the calculated density of the molten slag 26, the carburizing material 28 settles inside the molten slag 26 and carbonizes the molten iron 24 with high carbonization efficiency. FIG. 3 is a graph showing the carburizing efficiency of the carburized material. In FIG. 3, “MBC1” is a metal briquette manufactured by adding iron shot blast residue and tar to coke powder. "MBC2" is a metal briquette manufactured by adding a magnetically slag and a binder to coke powder. "Coke flour" is coke flour injected by injection from an oxygen lance. The “coke powder briquette” is a briquette formed by adding a binder to coke powder. Table 2 shows the compositions of these carburized materials, the apparent densities, and the calculated densities of molten slag after electric furnace refining using these carburized materials.
ＭＢＣ１およびＭＢＣ２は、溶融スラグ２６の計算密度よりも見かけ密度が高い加炭材である。一方、コークス粉およびコークス粉ブリケットは、溶融スラグ２６の計算密度よりも見かけ密度が低い加炭材である。なお、着炭効率は、投入した炭素質量に対する溶鉄の炭素濃度の増加に寄与した炭素質量の割合（質量％）である。 MBC1 and MBC2 are carburized materials having an apparent density higher than the calculated density of the molten slag 26. On the other hand, the coke powder and the coke powder briquette are carburizing materials having an apparent density lower than the calculated density of the molten slag 26. The carbonization efficiency is the ratio (mass %) of the mass of carbon that contributed to the increase in the carbon concentration of molten iron to the mass of carbon that was input.
図３に示すように、溶融スラグ２６の計算密度よりも見かけ密度が高い加炭材であるＭＢＣ１の着炭効率は９０質量％であり、ＭＢＣ２の着炭効率は９７質量％であった。一方、溶融スラグ２６の計算密度よりも見かけ密度が低い加炭材であるコークス粉の着炭効率は５０質量％であり、コークス粉ブリケットの着炭効率は４０質量％であった。このように、溶融スラグ２６の計算密度よりも加炭材の見かけ密度を高くすることで、加炭材の着炭効率を大きく向上できることが確認された。 As shown in FIG. 3, the carburizing efficiency of MBC1 which is a carburizing material having an apparent density higher than the calculated density of the molten slag 26 was 90 mass %, and the carburizing efficiency of MBC2 was 97 mass %. On the other hand, the carburizing efficiency of the coke powder, which is a carburizing material having an apparent density lower than the calculated density of the molten slag 26, was 50 mass %, and the carburizing efficiency of the coke powder briquette was 40 mass %. As described above, it was confirmed that the carburizing efficiency of the carburized material can be greatly improved by increasing the apparent density of the carburized material rather than the calculated density of the molten slag 26.
また、着炭効率の高い加炭材を用いることで、溶鉄２４の炭素濃度を高めることができる。濃度が高められた溶鉄２４の炭素は、溶融スラグ２６に含まれる酸化鉄等を還元し、溶融スラグ２６の各成分濃度が調整され、特に、溶融スラグ２６の鉄濃度が低減される。これにより、溶融スラグの鉄濃度を低い濃度に抑えた電気炉精錬が実現でき、電気炉精錬における鉄歩留まりを向上できる。 Moreover, the carbon concentration of the molten iron 24 can be increased by using a carburizing material having a high carbonization efficiency. The carbon of the molten iron 24 whose concentration has been increased reduces the iron oxide and the like contained in the molten slag 26, and the concentration of each component of the molten slag 26 is adjusted, and in particular, the iron concentration of the molten slag 26 is reduced. Thereby, electric furnace refining in which the iron concentration of the molten slag is suppressed to a low concentration can be realized, and the iron yield in the electric furnace refining can be improved.
次に、本発明に係る電気炉精錬方法を用いて、電気炉精錬を行なった実施例を説明する。電気炉容量が７０．０ｔで、トランス容量が３０，０００ｋＶＡの電気炉１０を用いて、スクラップ等の鉄屑を６５．０ｔと生石灰等の造滓材５．２ｔとを装入し、これらをアーク電極１６およびバーナー１８を用いて溶解した。表３に実施例の電気炉精錬条件を示す。 Next, an example of performing electric furnace refining using the electric furnace refining method according to the present invention will be described. Using an electric furnace 10 having an electric furnace capacity of 70.0t and a transformer capacity of 30,000kVA, 65.0t of iron scraps such as scraps and 5.2t of slag material such as quick lime are charged, and these are charged. It melted using the arc electrode 16 and the burner 18. Table 3 shows the electric furnace refining conditions of the examples.
実施例１として、シュート２０から表２に示したＭＢＣ１を１００．０ｋｇ投入し、その後、酸素ランスから１４３０Ｎｍ３（２２Ｎｍ３／ｔ−溶鉄）の酸素を吹込みながら、シュート２０からＭＢＣ１を分割して投入した。初期に投入した１００．０ｋｇのＭＢＣ１を含め、ＭＢＣ１を合計で６２４．０ｋｇ（加炭材原単位で９．６ｋｇ／ｔ−溶鉄 炭素分原単位で３．４ｋｇ／ｔ−溶銑）投入して、電気炉精錬を実施した。表４に実施例１における溶鉄の初期組成および終了組成を示す。また、溶融スラグの初期組成を表５に示す。 As Example 1, 100.0 kg of MBC1 shown in Table 2 was charged from the chute 20, and then MBC1 was divided from the chute 20 while blowing 1430 Nm 3 (22 Nm 3 /t-molten iron) of oxygen from an oxygen lance. I put it in. Including the initially charged 100.0 kg of MBC1, a total of 624.0 kg of MBC1 (9.6 kg/t-molten carbonaceous material unit-molten iron and 3.4 kg/t-molten pig iron per carbon content unit) were charged, Electric furnace refining was carried out. Table 4 shows the initial composition and the final composition of molten iron in Example 1. Table 5 shows the initial composition of the molten slag.
実施例２として、実施例１と同じ条件で、ＭＢＣ１をシュート２０から１００．０ｋｇ投入し、その後、酸素ランスから実施例１と同じ量の酸素を吹込みながら、シュート２０からＭＢＣ１を分割して投入した。初期に投入した１００．０ｋｇを含め、ＭＢＣ１を合計で３９０．０ｋｇ（加炭材原単位で６．０ｋｇ／ｔ−溶鉄 炭素分原単位で２．１ｋｇ／ｔ−溶銑）投入して、電気炉精錬を実施した。 As Example 2, MBC1 was charged from the chute 20 to 100.0 kg under the same conditions as in Example 1, and then the MBC1 was divided from the chute 20 while blowing the same amount of oxygen from the oxygen lance as in Example 1. I put it in. A total of 390.0 kg of MBC1 (6.0 kg/t-molten carbonaceous material-molten iron and 2.1 kg/t-molten pig iron per carbon content) including the initially charged 100.0 kg, was charged into an electric furnace. Performed refining.
実施例３として、実施例１と同じ条件で、ＭＢＣ１をシュート２０から１００．０ｋｇ投入し、その後、酸素ランスから実施例１と同じ量の酸素を吹込みながら、シュート２０からＭＢＣ１を分割して投入した。初期に投入した１００．０ｋｇを含め、ＭＢＣ１を合計で５５９０．０ｋｇ（加炭材原単位で８６．０ｋｇ／ｔ−溶鉄 炭素分原単位で３０．１ｋｇ／ｔ−溶銑）投入して、電気炉精錬を実施した。 As Example 3, MBC1 was charged from the chute 20 in an amount of 100.0 kg under the same conditions as in Example 1, and thereafter the MBC1 was divided from the chute 20 while blowing the same amount of oxygen from the oxygen lance as in Example 1. I put it in. A total of 5590.0 kg of MBC1 (86.0 kg/t-carbon steel unit/molten iron/carbon unit 30.1 kg/t-molten pig iron) was charged, including 100.0 kg initially charged, and the electric furnace Performed refining.
実施例４として、実施例１と同じ条件で、シュート２０から実施例１で用いたＭＢＣ１と炭素分原単位をあわせた量のＭＢＣ２を投入し、酸素ランスから実施例１と同じ量の酸素を吹込んで電気炉精錬を実施した。 As Example 4, under the same conditions as in Example 1, the amount of MBC2 used in Example 1 and the total amount of MBC2 used in Example 1 were added from the chute 20, and the same amount of oxygen as in Example 1 was supplied from the oxygen lance. It was blown in and electric furnace refining was carried out.
比較例１として、実施例１と同じ条件で、実施例１で用いたＭＢＣ１と炭素分原単位をあわせた量のコークス粉を酸素ランス２２からインジェクションで投入するとともに、酸素ランスから実施例１と同じ量の酸素を吹込んで電気炉精錬を実施した。 As Comparative Example 1, under the same conditions as in Example 1, the coke powder of the amount including the MBC1 used in Example 1 and the carbon basic unit was added by injection from the oxygen lance 22, and the oxygen lance was used as Example 1. Electric furnace refining was performed by blowing the same amount of oxygen.
比較例２として、実施例１と同じ条件で、実施例１で用いたＭＢＣ１と炭素分原単位をあわせた量のコークス粉ブリケットを投入し、酸素ランスから実施例１と同じ量の酸素を吹込んで電気炉精錬を実施した。表６は、実施例１から実施例４、および比較例１、２の電気炉精錬終了後の溶融スラグの各組成を示す。 As Comparative Example 2, under the same conditions as in Example 1, an amount of MBC1 used in Example 1 and the amount of the carbon content unit of the coke powder briquette were added, and the same amount of oxygen as in Example 1 was blown from the oxygen lance. Then, electric furnace refining was carried out. Table 6 shows the compositions of the molten slags after the completion of the electric furnace refining of Examples 1 to 4 and Comparative Examples 1 and 2.
実施例１における溶融スラグ組成の結果から、溶融スラグの計算密度よりも見かけ密度の高い加炭材であるＭＢＣ１を用いることで、溶融スラグの鉄濃度を２０質量％以下である１３質量％に抑えた電気炉精錬が実現できることがわかる。このように、溶融スラグの計算密度よりも高い見かけ密度の加炭材を用いることで、溶融スラグ中に含まれる鉄濃度を低くでき、これにより、電気炉精錬における鉄歩留まりを大きく向上できる。また、実施例２の結果から、溶融スラグの鉄濃度を２０質量％以下にするには、溶融スラグの計算密度よりも見かけ密度の高い加炭材を炭素原単位で２．１ｋｇ／ｔ−溶鉄以上となるように投入すればよいことがわかる。 From the result of the molten slag composition in Example 1, by using MBC1 which is a carburizing material having an apparent density higher than the calculated density of the molten slag, the iron concentration of the molten slag is suppressed to 13% by mass, which is 20% by mass or less. It is understood that the electric furnace refining can be realized. As described above, by using the carburizing material having an apparent density higher than the calculated density of the molten slag, the iron concentration contained in the molten slag can be lowered, and thus the iron yield in the electric furnace refining can be greatly improved. Further, from the results of Example 2, in order to reduce the iron concentration of the molten slag to 20% by mass or less, a carburizing material having a higher apparent density than the calculated density of the molten slag is used in a carbon basic unit of 2.1 kg/t-molten iron. It can be seen that the charging may be performed as described above.
一方、溶融スラグの鉄濃度が１０質量％未満になると、溶融スラグの流動性が悪化し、溶融スラグの排滓が困難になる。このため、溶融スラグの鉄濃度は１０質量％以上が好ましい。実施例３の結果から、溶融スラグの鉄濃度を１０質量％以上にするには、溶融スラグの計算密度よりも見かけ密度の高い加炭材を炭素原単位で、３０．１ｋｇ／ｔ−溶鉄以下となるように、当該加炭材を投入すればよいことがわかる。 On the other hand, when the iron concentration of the molten slag is less than 10% by mass, the fluidity of the molten slag deteriorates, and it becomes difficult to discharge the molten slag. Therefore, the iron concentration of the molten slag is preferably 10% by mass or more. From the results of Example 3, in order to increase the iron concentration of the molten slag to 10% by mass or more, the carburizing material having an apparent density higher than the calculated density of the molten slag is 30.1 kg/t-molten iron or less in terms of carbon unit. It is understood that the carburizing material may be added so that
このように、溶融スラグの計算密度よりも見かけ密度が高い加炭材を用いることで、電気炉精錬終了後の溶融スラグの各成分濃度を調整でき、この結果、溶融スラグの鉄濃度を１０質量％以上であって２０質量％以下にできる。この溶融スラグの組成および計算密度から、溶融スラグの計算密度よりも見かけ密度が高い加炭材を用いることで、電気炉精錬終了後の溶融スラグが下記の数式（１）を満足するような電気炉精錬を実施できる。 In this way, by using a carburizing material having an apparent density higher than the calculated density of the molten slag, the concentration of each component of the molten slag after the electric furnace refining can be adjusted, and as a result, the iron concentration of the molten slag is 10 mass. % Or more and 20% by mass or less. From the composition and calculated density of this molten slag, by using a carburizing material whose apparent density is higher than the calculated density of the molten slag, the molten slag after the electric furnace refining is finished to satisfy the following formula (1). Can perform furnace refining.
３６００≦｛（ＦｅＯ質量％）＋（ＳｉＯ２質量％）＋（ＣａＯ質量％）＋（Ａｌ２Ｏ３質量％）＋（ＭｇＯ質量％）＋（ＭｎＯ質量％）｝／｛（ＦｅＯ質量％）／５７４０＋（ＳｉＯ２質量％）／２７００＋（ＣａＯ質量％）／３２００＋（Ａｌ２Ｏ３質量％）／４０００＋（ＭｇＯ質量％）／３６００＋（ＭｎＯ質量％）／５４００｝≦４２１５・・・数式（１） 3600≦{(FeO mass%)+(SiO 2 mass%)+(CaO mass%)+(Al 2 O 3 mass%)+(MgO mass%)+(MnO mass%)}/{(FeO mass%) /5740+(SiO 2 mass %)/2700+(CaO mass %)/3200+(Al 2 O 3 mass %)/4000+(MgO mass %)/3600+(MnO mass %)/5400}≦4215... )
比較例１は、溶融スラグの計算密度よりも見かけ密度が低い加炭材であるコークス粉を用いて電気炉精錬を行なった結果である。溶融スラグの計算密度よりも見かけ密度が低いコークス粉を、酸素ランスを用いてインジェクションで投入しても、溶鉄の炭素濃度を高めることができず、電気炉精錬終了後の溶融スラグの成分濃度を調整して溶融スラグの鉄濃度を低下させることができない。このため、比較例１の電気炉精錬後の溶融スラグの計算密度は、表６に示すように４３３０ｋｇ／ｍ３になり、上記数式（１）を満足しない。 Comparative Example 1 is a result of electric furnace refining using coke powder which is a carburizing material having an apparent density lower than the calculated density of molten slag. Even if the coke powder having an apparent density lower than the calculated density of the molten slag is injected by using an oxygen lance, the carbon concentration of the molten iron cannot be increased, and the component concentration of the molten slag after the electric furnace refining is finished. It cannot be adjusted to reduce the iron concentration in the molten slag. Therefore, the calculated density of the molten slag after the electric furnace refining in Comparative Example 1 is 4330 kg/m 3 as shown in Table 6, which does not satisfy the above mathematical expression (1).
比較例２は、溶融スラグの計算密度よりも見かけ密度が低い加炭材であるコークス粉ブリケットを用いて電気炉精錬を行なった結果である。溶融スラグの計算密度よりも見かけ密度が低いコークス粉ブリケットを投入しても、溶鉄の炭素濃度を高めることができない。このため、電気炉精錬後の溶融スラグの成分濃度を調整し、溶融スラグの鉄濃度を低下させることができない。このため、比較例２の電気炉精錬終了後の溶融スラグの計算密度は、表６に示すように４２９９ｋｇ／ｍ３になり、上記数式（１）を満足しない。 Comparative Example 2 is a result of electric furnace refining using a coke powder briquette, which is a carburizing material having an apparent density lower than the calculated density of the molten slag. Even if a coke powder briquette having an apparent density lower than the calculated density of molten slag is added, the carbon concentration of molten iron cannot be increased. For this reason, it is impossible to adjust the component concentration of the molten slag after refining the electric furnace and reduce the iron concentration of the molten slag. Therefore, the calculated density of the molten slag after the completion of the electric furnace refining of Comparative Example 2 is 4299 kg/m 3 as shown in Table 6, which does not satisfy the above mathematical expression (1).
以上、説明したように、本発明に係る加炭材を用いた電気炉精錬方法を実施して、電気炉精錬終了後における溶融スラグの鉄濃度を含む成分濃度から算出される計算密度を３６００ｋｇ／ｍ３以上４２１５ｋｇ／ｍ３以下の範囲内に調整する。これにより、溶融スラグの計算密度よりも見かけ密度が低い加炭材を用いて電気炉精錬を実施した場合よりも溶融スラグの鉄濃度を低い濃度に抑えた電気炉精錬が実現でき、電気炉精錬における鉄歩留まりを向上できる。一方、比較例１および比較例２として示したコークス粉およびコークス粉ブリケットを用いても、電気炉精錬終了後における溶融スラグの計算密度を３６００ｋｇ／ｍ３以上４２１５ｋｇ／ｍ３以下の範囲内に調整できず、溶融スラグの鉄濃度を低く抑えた電気炉精錬が実現できない。 As described above, the electric furnace refining method using the carburizing material according to the present invention is performed, and the calculated density calculated from the component concentration including the iron concentration of the molten slag after the electric furnace refining is 3600 kg/ m is adjusted to 3 or more 4215Kg / m 3 within the following range. As a result, it is possible to realize electric furnace refining in which the iron concentration of the molten slag is suppressed to a lower concentration than when the electric furnace refining is performed using a carburizing material whose apparent density is lower than the calculated density of the molten slag. Can improve the iron yield. On the other hand, even when the coke powder and the coke powder briquette shown as Comparative Example 1 and Comparative Example 2 were used, the calculated density of the molten slag after the completion of the electric furnace refining was adjusted within the range of 3600 kg/m 3 or more and 4215 kg/m 3 or less. This is not possible, and electric furnace refining with a low iron concentration in the molten slag cannot be realized.
１０ 電気炉
１２ 炉本体
１４ 炉蓋
１６ アーク電極
１８ バーナー
２０ シュート
２２ 酸素ランス
２４ 溶鉄
２６ 溶融スラグ
２８ 加炭材
３０ 加炭材
10 Electric Furnace 12 Furnace Main Body 14 Furnace Lid 16 Arc Electrode 18 Burner 20 Chute 22 Oxygen Lance 24 Molten Iron 26 Molten Slag 28 Carburizing Material 30 Carburizing Material
Claims (1)
バインダーと、
鉄、鉄酸化物、マンガンおよびマンガン酸化物の少なくとも１つと、
を含む加炭材を溶鉄に投入する電気炉精錬方法であって、
電気炉精錬におけるスラグの計算密度よりも見かけ密度が高い前記加炭材を溶鉄に投入し、電気炉精錬終了後の前記スラグの組成が下記の数式（１）を満足することを特徴とする電気炉精錬方法。
３６００≦｛（ＦｅＯ質量％）＋（ＳｉＯ２質量％）＋（ＣａＯ質量％）＋（Ａｌ２Ｏ３質量％）＋（ＭｇＯ質量％）＋（ＭｎＯ質量％）｝／｛（ＦｅＯ質量％）／５７４０＋（ＳｉＯ２質量％）／２７００＋（ＣａＯ質量％）／３２００＋（Ａｌ２Ｏ３質量％）／４０００＋（ＭｇＯ質量％）／３６００＋（ＭｎＯ質量％）／５４００｝≦４２１５・・・数式（１）
但し、上記数式（１）において、（ＦｅＯ質量％）は、前記スラグ中のＦｅＯ濃度を表し、（ＳｉＯ２質量％）は、前記スラグ中のＳｉＯ２濃度を表し、（ＣａＯ質量％）は、前記スラグ中のＣａＯ濃度を表し、（Ａｌ２Ｏ３質量％）は、前記スラグ中のＡｌ２Ｏ３濃度を表し、（ＭｇＯ質量％）は、前記スラグ中のＭｇＯ濃度を表し、（ＭｎＯ質量％）は、前記スラグ中のＭｎＯ濃度を表す。 Carbonaceous powder,
A binder,
At least one of iron, iron oxide, manganese, and manganese oxide;
An electric furnace refining method in which a carburizing material containing
The above-mentioned carburizing material having a higher apparent density than the calculated density of slag in the electric furnace refining is charged into molten iron, and the composition of the slag after the electric furnace refining is satisfied by the following mathematical expression (1). Furnace refining method.
3600≦{(FeO mass%)+(SiO 2 mass%)+(CaO mass%)+(Al 2 O 3 mass%)+(MgO mass%)+(MnO mass%)}/{(FeO mass%) /5740+(SiO 2 mass %)/2700+(CaO mass %)/3200+(Al 2 O 3 mass %)/4000+(MgO mass %)/3600+(MnO mass %)/5400}≦4215... )
However, in the above formula (1), (FeO mass%) represents the FeO concentration in the slag, (SiO 2 mass%) represents the SiO 2 concentration in the slag, and (CaO mass%) is It represents the CaO concentration in the slag, (Al 2 O 3 mass%) represents the Al 2 O 3 concentration in the slag, (MgO mass%) represents the MgO concentration in the slag, (MnO mass %) represents the MnO concentration in the slag.
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