JP7575683B2 - Carbon-containing agglomerate for blast furnace and method for operating blast furnace using same - Google Patents
Carbon-containing agglomerate for blast furnace and method for operating blast furnace using same Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims description 243
- 229910052799 carbon Inorganic materials 0.000 title claims description 243
- 238000000034 method Methods 0.000 title claims description 19
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 134
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 69
- 229910052742 iron Inorganic materials 0.000 claims description 65
- 239000003638 chemical reducing agent Substances 0.000 description 58
- 239000002994 raw material Substances 0.000 description 34
- 239000000571 coke Substances 0.000 description 24
- 230000000694 effects Effects 0.000 description 23
- 239000007789 gas Substances 0.000 description 17
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 16
- 229910052760 oxygen Inorganic materials 0.000 description 16
- 239000001301 oxygen Substances 0.000 description 16
- 239000003575 carbonaceous material Substances 0.000 description 12
- 239000000428 dust Substances 0.000 description 9
- 239000002245 particle Substances 0.000 description 9
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 230000009467 reduction Effects 0.000 description 8
- 239000003245 coal Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 239000011230 binding agent Substances 0.000 description 6
- 238000002309 gasification Methods 0.000 description 6
- 230000003197 catalytic effect Effects 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910000805 Pig iron Inorganic materials 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 239000002893 slag Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 239000004484 Briquette Substances 0.000 description 2
- 239000011398 Portland cement Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000001808 coupling effect Effects 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052595 hematite Inorganic materials 0.000 description 2
- 239000011019 hematite Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 1
- 239000003830 anthracite Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000000368 destabilizing effect Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- -1 more specifically Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 description 1
- 235000019982 sodium hexametaphosphate Nutrition 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 238000004876 x-ray fluorescence Methods 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
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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
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- Manufacture And Refinement Of Metals (AREA)
Description
本発明は、高炉用含炭塊成鉱及びそれを用いた高炉の操業方法に関する。 The present invention relates to carbon-containing agglomerated ore for blast furnaces and a method for operating a blast furnace using the same.
鉄鋼業においては、高炉法が銑鉄製造工程の主流を担っている。高炉法においては、高炉の炉頂から高炉用鉄系原料（主として焼結鉱）及びコークスを高炉内に交互かつ層状に装入する一方で、高炉下部の羽口から熱風を高炉内に吹き込む。熱風は、熱風とともに吹き込まれる微粉炭、及び、高炉内のコークスと反応することで、高温の還元ガス（ここでは主としてＣＯガス）を発生させる。すなわち、熱風は、コークス及び微粉炭をガス化させる。還元ガスは、高炉内を上昇し、鉄系原料を加熱しながら還元する。鉄系原料は、高炉内を降下する一方で、還元ガスにより加熱及び還元される。その後、鉄系原料は溶融し、コークスによってさらに還元されながら高炉内を滴下する。鉄系原料は、最終的には炭素を５質量％弱含む溶銑（銑鉄）として炉床部に溜められる。炉床部の溶銑は、出銑口から取り出され、次の製鋼プロセスに供される。したがって、高炉法では、コークス及び微粉炭等の炭材を還元材として使用する。 In the steel industry, the blast furnace process is the mainstream of pig iron manufacturing processes. In the blast furnace process, iron-based raw materials for the blast furnace (mainly sintered ore) and coke are charged into the blast furnace alternately and in layers from the top of the blast furnace, while hot air is blown into the blast furnace from the tuyere at the bottom of the blast furnace. The hot air reacts with the pulverized coal blown in together with the hot air and the coke in the blast furnace to generate high-temperature reducing gas (mainly CO gas in this case). In other words, the hot air gasifies the coke and pulverized coal. The reducing gas rises in the blast furnace and reduces the iron-based raw materials while heating them. The iron-based raw materials descend in the blast furnace while being heated and reduced by the reducing gas. The iron-based raw materials are then melted and dripped into the blast furnace while being further reduced by the coke. The iron-based raw materials are finally stored in the hearth as molten pig iron (pig iron) containing just under 5% carbon by mass. The molten iron in the hearth is taken out through a tap hole and used in the next steelmaking process. Therefore, in the blast furnace process, carbonaceous materials such as coke and pulverized coal are used as reducing agents.
ところで、近年、地球温暖化防止が叫ばれ、温室効果ガスの一つである二酸化炭素（ＣＯ２ガス）の排出量削減が社会問題になっている。上述したように、高炉法では、還元材として炭材を使用するので、大量のＣＯ２ガスを発生する。したがって、鉄鋼業はＣＯ２ガス排出量において主要な産業のひとつとなっており、その社会的要請に応えねばならない。具体的には、高炉操業での更なる還元材比（溶銑１トンあたりの還元材使用量であり、ＲＡＲとも称される）の削減が急務となっている。 Recently, the prevention of global warming has been called for, and the reduction of carbon dioxide ( CO2 gas) emissions, which is one of the greenhouse gases, has become a social issue. As described above, the blast furnace process uses carbonaceous materials as a reducing agent, which generates a large amount of CO2 gas. Therefore, the steel industry is one of the major industries in terms of CO2 gas emissions, and must respond to this social demand. Specifically, there is an urgent need to further reduce the reducing agent ratio (the amount of reducing agent used per ton of molten iron, also called RAR) in blast furnace operation.
還元材比を低減させるための技術の１つとして、含炭塊成鉱を焼結鉱の一部に代替して使用することが知られている。ここに、含炭塊成鉱は、鉄鉱石等の酸化鉄原料と炭材とを配合し、塊成化させたものである。含炭塊成鉱においては、酸化鉄原料と炭材とが近接しているため、カップリング効果により炭材中のカーボン（Ｃ成分）がガス化しやすい。このため、含炭塊成鉱を高炉用鉄系原料として使用することで、還元材比の低減が期待される。 One of the techniques for reducing the reducing agent ratio is known to use carbon-containing agglomerates as a partial replacement for sintered ore. Carbon-containing agglomerates are made by blending iron oxide raw materials such as iron ore with carbonaceous material and agglomerating them. In carbon-containing agglomerates, the iron oxide raw materials and the carbonaceous material are in close proximity to each other, so the coupling effect makes it easy for the carbon (C component) in the carbonaceous material to gasify. For this reason, it is expected that the reducing agent ratio can be reduced by using carbon-containing agglomerates as an iron-based raw material for blast furnaces.
一方で、金属鉄にカーボンのガス化促進（カーボン反応性促進）の触媒作用があることはよく知られている。このような金属鉄の触媒作用を利用したフェロコークスも広く検討されている。フェロコークスは、例えば低品位の石炭と鉄鉱石とを混合して成型した後、空気を遮断した状態で加熱することで製造される。 On the other hand, it is well known that metallic iron has a catalytic effect in promoting the gasification of carbon (promoting carbon reactivity). Ferro coke, which utilizes the catalytic effect of metallic iron, is also being widely studied. Ferro coke is produced, for example, by mixing low-grade coal and iron ore, molding the mixture, and then heating it in an air-tight environment.
特許文献１及び非特許文献１、２には、含炭塊成鉱及びフェロコークスの技術を併用した技術、すなわち含炭塊成鉱にさらに金属鉄（Ｍ．Ｆｅ）を混合する技術が開示されている。 Patent Document 1 and Non-Patent Documents 1 and 2 disclose a technology that combines the technologies of carbon-containing agglomerates and ferro-coke, that is, a technology in which metallic iron (M.Fe) is further mixed into the carbon-containing agglomerates.
しかし、金属鉄を含有する含炭塊成鉱において、金属鉄とカーボンとの好適な組み合わせ条件はこれまで全く知られておらず、上述した含炭塊成鉱及びフェロコークスの利点を十分に生かしているとは言い難かった。 However, in carbon-bearing agglomerates containing metallic iron, the optimum conditions for combining metallic iron with carbon were completely unknown, and it was difficult to say that the advantages of the carbon-bearing agglomerates and ferro-coke described above were being fully utilized.
本発明は、上記問題に鑑みてなされたものであり、本発明の目的とするところは、還元材比をより低減することが可能な高炉用含炭塊成鉱及びそれを用いた高炉の操業方法を提供することである。 The present invention was made in consideration of the above problems, and the object of the present invention is to provide a carbon-containing agglomerated ore for blast furnaces that can further reduce the reducing agent ratio, and a method for operating a blast furnace using the same.
上記課題を解決するために、本発明のある観点によれば、カーボン、金属鉄、及び酸化鉄を合計で７０質量％以上含有する高炉用含炭塊成鉱であって、カーボンの含有量が高炉用含炭塊成鉱の総質量に対して１５～２５質量％であり、金属鉄とカーボンの質量比が０．４～０．８であることを特徴とする、高炉用含炭塊成鉱が提供される。 In order to solve the above problems, according to one aspect of the present invention, there is provided a carbon-containing agglomerate for blast furnaces containing a total of 70 mass% or more of carbon, metallic iron, and iron oxide, characterized in that the carbon content is 15 to 25 mass% of the total mass of the carbon-containing agglomerate for blast furnaces, and the mass ratio of metallic iron to carbon is 0.4 to 0.8.
本発明の他の観点によれば、上記の高炉用含炭塊成鉱を用いた高炉の操業方法であって、高炉用含炭塊成鉱由来のカーボン原単位を５～３０ｋｇ／ｔ－ＨＭとすることを特徴とする、高炉の操業方法が提供される。 According to another aspect of the present invention, there is provided a method for operating a blast furnace using the above-mentioned carbon-containing agglomerated ore for blast furnaces, characterized in that the carbon consumption rate derived from the carbon-containing agglomerated ore for blast furnaces is 5 to 30 kg/t-HM.
本発明の上記観点によれば、還元材比をより低減することが可能な高炉用含炭塊成鉱及びそれを用いた高炉の操業方法を提供することができる。 According to the above-mentioned aspects of the present invention, it is possible to provide a carbon-containing agglomerate for blast furnaces that can further reduce the reducing agent ratio, and a method for operating a blast furnace using the same.
以下に添付図面を参照しながら、本発明の好適な実施の形態について詳細に説明する。本発明者は、金属鉄を含む高炉用含炭塊成鉱（以下、単に「含炭塊成鉱」とも称する）の組成について鋭意検討し、その結果、金属鉄とカーボンとの好適な組み合わせ条件を見出すことができた。そして、本発明者は、このような知見の下、本実施形態に係る含炭塊成鉱及びそれを用いた高炉の操業方法に想到することができた。なお、本実施形態において、「カーボン」とは、含炭塊成鉱等に使用される「炭材」そのものではなく、「炭材」に含まれる「炭素（Ｃ）成分」を意味するものとする。「酸化鉄」には、ウスタイト（ＦｅＯ）、マグネタイト（Ｆｅ３Ｏ４）及びヘマタイト（Ｆｅ２Ｏ３）が含まれる。また、本実施形態に係る単位の「／ｔ－ＨＭ」は、溶銑１トンの製造に必要な量、いわゆる原単位を示す。本実施形態において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値及び上限値として含む範囲を意味する。以下、本実施形態に係る含炭塊成鉱及びそれを用いた高炉の操業方法について詳細に説明する。 A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The present inventors have intensively studied the composition of carbon-containing agglomerates for blast furnaces containing metallic iron (hereinafter, also simply referred to as "carbon-containing agglomerates"), and as a result, have been able to find a suitable combination condition of metallic iron and carbon. Based on such findings, the present inventors have been able to conceive of the carbon-containing agglomerates according to this embodiment and the method of operating a blast furnace using the same. In this embodiment, "carbon" does not mean the "carbon material" itself used in carbon-containing agglomerates, etc., but rather means the "carbon (C) component" contained in the "carbon material". "Iron oxide" includes wustite (FeO), magnetite (Fe 3 O 4 ), and hematite (Fe 2 O 3 ). In addition, the unit "/t-HM" according to this embodiment indicates the amount required to produce 1 ton of molten iron, that is, the so-called basic unit. In this embodiment, a numerical range expressed using "to" means a range including the numerical values written before and after "to" as the lower and upper limits. Hereinafter, the carbon-containing agglomerated ore according to the present embodiment and the method for operating a blast furnace using the same will be described in detail.
＜１．含炭塊成鉱の組成＞
本実施形態に係る含炭塊成鉱は、少なくともカーボン、金属鉄、及び酸化鉄を合計で含炭塊成鉱の総質量に対して７０質量％以上含有する。この条件が満たされない場合、還元材比を十分に低減することができない。つまり、含炭塊成鉱は、主にカーボン、金属鉄、及び酸化鉄で構成されるが、残部はスラグ（ＣａＯ、ＳｉＯ２、Ａｌ２Ｏ３等）、結晶水などで構成される。カーボン、金属鉄、及び酸化鉄の含有量が少ないことは、その分スラグ成分が増加することになる。したがって、高炉内でスラグ成分の溶解に必要な還元材が増大し、ひいては還元材比が増大する。
<1. Composition of carbon-bearing agglomerates>
The carbon-containing agglomerates according to the present embodiment contain at least carbon, metallic iron, and iron oxide in a total amount of 70 mass% or more based on the total mass of the carbon-containing agglomerates. If this condition is not met, the reducing agent ratio cannot be sufficiently reduced. In other words, the carbon-containing agglomerates are mainly composed of carbon, metallic iron, and iron oxide, with the remainder being composed of slag (CaO, SiO2 , Al2O3 , etc. ), crystal water, etc. A low content of carbon, metallic iron, and iron oxide means that the slag components increase accordingly. Therefore, the reducing agent required to dissolve the slag components in the blast furnace increases, and the reducing agent ratio increases accordingly.
さらに、本実施形態に係る含炭塊成鉱では、カーボンの含有量が高炉用含炭塊成鉱の総質量に対して１５～２５質量％である。カーボンの含有量がこの範囲内の値となる場合に、カーボンによる効果が効果的に現れ、ひいては、還元材比が低減する。ここに、カーボンによる効果としては、酸化鉄にカーボンが近接することによるカーボンのガス化促進効果（所謂カップリング効果）、金属鉄の触媒作用によるカーボンのガス化促進効果等が挙げられる。カーボン含有量の好ましい上限値は２０質量％である。つまり、カーボン含有量は、好ましくは１５～２０質量％である。 Furthermore, in the carbon-containing agglomerates according to this embodiment, the carbon content is 15 to 25 mass% relative to the total mass of the blast furnace carbon-containing agglomerates. When the carbon content is within this range, the effect of carbon is effectively manifested, and the reducing agent ratio is reduced. Examples of the effect of carbon include the gasification promotion effect of carbon due to its proximity to iron oxide (the so-called coupling effect), and the gasification promotion effect of carbon due to the catalytic action of metallic iron. The preferred upper limit of the carbon content is 20 mass%. In other words, the carbon content is preferably 15 to 20 mass%.
カーボンの含有量が１５質量％未満となる場合、カーボンによる効果を十分に享受できず、還元材比が十分に低減しない。つまり、含炭塊成鉱からは還元ガス（ＣＯ）が容易に発生するため、還元材比の低減に寄与する。しかし、カーボンの含有量が１５質量％未満となる場合、そもそも含炭塊成鉱から発生する還元ガス自体が少なくなるので、還元材比が十分に低減しない。 If the carbon content is less than 15% by mass, the effect of carbon cannot be fully enjoyed, and the reducing agent ratio does not decrease sufficiently. In other words, reducing gas (CO) is easily generated from carbon-containing agglomerates, which contributes to reducing the reducing agent ratio. However, if the carbon content is less than 15% by mass, the reducing gas generated from the carbon-containing agglomerates is reduced in the first place, and the reducing agent ratio does not decrease sufficiently.
一方、カーボンの含有量が２５質量％を超えると、含炭塊成鉱中の酸化鉄の含有量、すなわち被還元酸素量（酸化鉄に結合した酸素量）が極端に少なくなる。このため、カーボンによる効果を十分に享受できない。つまり、含炭塊成鉱からは還元ガス（ＣＯ）が容易に発生する。しかし、カーボンの含有量が２５質量％を超えると、還元ガスの直近に存在する被還元酸素が少なくなるため、還元ガスによる効果を十分に享受できない。すなわち、カーボンによる効果を十分に享受できない。さらに、カーボンの含有量が２５質量％を超えると、含炭塊成鉱の熱間強度が低下して、操業が不安定化する可能性もある。これらの結果、還元材比が十分に低減しないのみならず、かえって上昇してしまう可能性もある。 On the other hand, if the carbon content exceeds 25% by mass, the iron oxide content in the carbon-containing agglomerates, i.e., the amount of oxygen to be reduced (the amount of oxygen bonded to iron oxide), becomes extremely small. As a result, the effect of carbon cannot be fully enjoyed. In other words, reducing gas (CO) is easily generated from the carbon-containing agglomerates. However, if the carbon content exceeds 25% by mass, the amount of oxygen to be reduced in the immediate vicinity of the reducing gas decreases, so the effect of the reducing gas cannot be fully enjoyed. In other words, the effect of carbon cannot be fully enjoyed. Furthermore, if the carbon content exceeds 25% by mass, the hot strength of the carbon-containing agglomerates decreases, which may cause operation to become unstable. As a result of these factors, not only is the reducing agent ratio not reduced sufficiently, but it may even increase.
さらに、金属鉄とカーボンの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）が０．４～０．８である。この場合、金属鉄の触媒作用によるカーボンのガス化促進効果が十分に得られ、還元材比が低減する。金属鉄とカーボンの質量比が０．４未満となる場合、カーボンのガス化促進効果が十分に得られず、特に５０～１５０ｋｇ／ｔ－ＨＭで高炉操業を行う場合に、還元材比が十分に低減しない。一方、金属鉄とカーボンの質量比が０．８を超える場合、カーボン量が相対的に低くなり、カーボンによる効果を十分に享受できない。つまり、金属鉄は十分に存在するのでカーボンのガス化は十分に促進されるが、そもそも発生する還元ガス自体が少なくなるので、還元材比が十分に低減しない。すなわち、カーボンによる効果を十分に享受できない。金属鉄とカーボンの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）の好ましい下限値は０．５であり、好ましい上限値は０．７である。 Furthermore, the mass ratio of metallic iron to carbon (M.Fe/T.C) is 0.4 to 0.8. In this case, the catalytic action of metallic iron is sufficient to promote the gasification of carbon, and the reducing agent ratio is reduced. If the mass ratio of metallic iron to carbon is less than 0.4, the gasification promotion effect of carbon is not sufficiently achieved, and the reducing agent ratio is not sufficiently reduced, particularly when blast furnace operation is performed at 50 to 150 kg/t-HM. On the other hand, if the mass ratio of metallic iron to carbon is more than 0.8, the amount of carbon becomes relatively low, and the effect of carbon cannot be fully enjoyed. In other words, since there is sufficient metallic iron, the gasification of carbon is sufficiently promoted, but the reducing gas itself generated is reduced in the first place, so the reducing agent ratio is not sufficiently reduced. In other words, the effect of carbon cannot be fully enjoyed. The preferable lower limit of the mass ratio of metallic iron to carbon (M.Fe/T.C) is 0.5, and the preferable upper limit is 0.7.
図１は、本実施形態に係る金属鉄とカーボンとの組み合わせの範囲と従来の範囲とを対比して示すグラフである。 Figure 1 is a graph showing the range of combinations of metallic iron and carbon according to this embodiment compared to the conventional range.
図１の横軸は含炭塊成鉱に含まれるカーボン（Ｔ．Ｃ）の含有量（質量％）を示し、縦軸は含炭塊成鉱に含まれる金属鉄（Ｍ．Ｆｅ）の含有量（質量％）を示す。グラフＬ１はＭ．Ｆｅ／Ｔ．Ｃ＝０．８を示し、グラフＬ２はＭ．Ｆｅ／Ｔ．Ｃ＝０．４を示す。グラフＬ３、Ｌ４はそれぞれカーボン含有量＝１５質量％、２５質量％を示す。したがって、グラフＬ１～Ｌ４で囲まれる領域Ａ１が本実施形態に係る含炭塊成鉱が満たすべき条件（金属鉄とカーボンとの組み合わせ条件）を示す。 The horizontal axis of FIG. 1 indicates the carbon (T.C) content (mass%) contained in the carbon-containing agglomerates, and the vertical axis indicates the metallic iron (M.Fe) content (mass%) contained in the carbon-containing agglomerates. Graph L1 indicates M.Fe/T.C=0.8, and graph L2 indicates M.Fe/T.C=0.4. Graphs L3 and L4 indicate carbon contents of 15 mass% and 25 mass%, respectively. Therefore, the area A1 surrounded by graphs L1 to L4 indicates the conditions (combination conditions of metallic iron and carbon) that the carbon-containing agglomerates according to this embodiment must satisfy.
一方、領域Ｂは非特許文献２に開示された範囲を示し、点Ｃ１、点Ｃ２、及びこれらを連結するグラフＣは特許文献１に開示された範囲を示す。図示は省略するが、非特許文献１では、概ねカーボン含有量を１０質量％程度としている。したがって、いずれの範囲も本実施形態に係る含炭塊成鉱が満たすべき範囲を外れている。 On the other hand, region B indicates the range disclosed in Non-Patent Document 2, and points C1, C2, and the graph C connecting them indicate the range disclosed in Patent Document 1. Although not shown, Non-Patent Document 1 generally sets the carbon content at about 10 mass%. Therefore, both ranges are outside the range that the carbon-containing agglomerated ore according to this embodiment should satisfy.
図２は、含炭塊成鉱に含まれる金属鉄とカーボンの好ましい質量比を説明するためのグラフである。具体的には、図２は、含炭塊成鉱に含まれる金属鉄とカーボンとの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）と、還元材比ＲＡＲ（ｋｇ／ｔ－ＨＭ）との関係を含炭塊成鉱に含まれるカーボン含有量（含炭塊成鉱の総質量に対する質量％）毎に示す。図２の横軸は含炭塊成鉱に含まれる金属鉄とカーボンの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）を示し、縦軸は還元材比ＲＡＲ（ｋｇ／ｔ－ＨＭ）を示す。還元材比は後述の実施例で測定された値である。なお、実施例では高炉を模擬したＢＩＳ炉（内藤ほか：鉄と鋼、８７巻（２００１年）、Ｎｏ．５、Ｐ．３５７－３６４）により還元材比を測定した。詳細な試験条件は後述する実施例と同様とし、含炭塊成鉱由来のカーボン原単位は２０ｋｇ／ｔ－ＨＭとした。 Figure 2 is a graph for explaining the preferred mass ratio of metallic iron and carbon contained in the carbon-containing agglomerates. Specifically, Figure 2 shows the relationship between the mass ratio of metallic iron and carbon contained in the carbon-containing agglomerates (M.Fe/T.C) and the reducing agent ratio RAR (kg/t-HM) for each carbon content (mass % relative to the total mass of the carbon-containing agglomerates) contained in the carbon-containing agglomerates. The horizontal axis of Figure 2 shows the mass ratio of metallic iron and carbon contained in the carbon-containing agglomerates (M.Fe/T.C), and the vertical axis shows the reducing agent ratio RAR (kg/t-HM). The reducing agent ratio is a value measured in the examples described later. In the examples, the reducing agent ratio was measured using a BIS furnace (Naito et al.: Iron and Steel, Vol. 87 (2001), No. 5, pp. 357-364) that simulates a blast furnace. The detailed test conditions were the same as those in the examples described later, and the carbon consumption unit derived from the carbon-containing agglomerates was 20 kg/t-HM.
点Ｐ１０はカーボン含有量＝１５質量％となる場合におけるＭ．Ｆｅ／Ｔ．Ｃ及び還元材比の測定値を示し、グラフＬ１０は点Ｐ１０を連結したグラフである。点Ｐ２０はカーボン含有量＝２５質量％となる場合におけるＭ．Ｆｅ／Ｔ．Ｃ及び還元材比の測定値を示し、グラフＬ２０は点Ｐ２０を連結したグラフである。グラフＬ３０、Ｌ４０はそれぞれＭ．Ｆｅ／Ｔ．Ｃ＝０．４、０．８を示す。グラフＬ１０～Ｌ４０で囲まれる領域Ａ２が本実施形態に係る含炭塊成鉱が満たすべき条件（金属鉄とカーボンとの組み合わせ条件）を示す。点Ｐ３０は含炭塊成鉱を使用しないベース操業（カーボン含有量＝０質量となる操業）を示す。図１及び図２から明らかな通り、領域Ａ１、Ａ２の条件を満たす場合、還元材比がカーボン含有量＝０質量となる操業と比べて大きく低減していることがわかる。また、カーボン含有量が同一の条件下で比較してみると、金属鉄とカーボンとの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）が０．４～０．８となる場合に、還元材比が大きく低減していることがわかる。つまり、本実施形態の目的は、含炭塊成鉱中のカーボンを如何に効率よく使用するかという点にあるので、カーボン含有量が同一となる含炭塊成鉱同士で還元材比の低減効果を比較する必要がある。 Point P10 shows the measured values of M.Fe/T.C and the reducing agent ratio when the carbon content is 15% by mass, and graph L10 is a graph connecting the points P10. Point P20 shows the measured values of M.Fe/T.C and the reducing agent ratio when the carbon content is 25% by mass, and graph L20 is a graph connecting the points P20. Graphs L30 and L40 show M.Fe/T.C = 0.4 and 0.8, respectively. Area A2 surrounded by graphs L10 to L40 shows the conditions (combination conditions of metallic iron and carbon) that the carbon-containing agglomerates according to this embodiment should satisfy. Point P30 shows the base operation (operation in which the carbon content is 0 mass) in which the carbon-containing agglomerates are not used. As is clear from FIG. 1 and FIG. 2, when the conditions of areas A1 and A2 are satisfied, the reducing agent ratio is significantly reduced compared to the operation in which the carbon content is 0 mass. In addition, when comparing under conditions where the carbon content is the same, it can be seen that the reducing agent ratio is significantly reduced when the mass ratio of metallic iron to carbon (M.Fe/T.C) is 0.4 to 0.8. In other words, since the purpose of this embodiment is to use the carbon in the carbon-containing agglomerates as efficiently as possible, it is necessary to compare the reducing agent ratio reduction effect between carbon-containing agglomerates with the same carbon content.
含炭塊成鉱は上記の条件を満たしていればよいが、さらにＣ／Ｏが１．０～２．０程度であってもよい。この場合、還元材比がさらに低減される場合がある。なお、Ｃ／Ｏ中のＣは含炭塊成鉱中のカーボンを示し、Ｏは含炭塊成鉱中の被還元酸素を示す。Ｃ／Ｏはこれらのモル比を示す。また、含炭塊成鉱の粒度も特に制限されず、従来の含炭塊成鉱と同程度であってもよい。例えば、含炭塊成鉱の粒度は５～１５ｍｍ程度であってもよい。なお、含炭塊成鉱の粒度は目開きの異なる篩で分級することができる。目開き１５ｍｍの篩から落ち、目開き５ｍｍの篩に残る含炭塊成鉱の粒度は、５～１５ｍｍの範囲内となる。 The carbon-containing agglomerates may satisfy the above conditions, but may also have a C/O of about 1.0 to 2.0. In this case, the reducing agent ratio may be further reduced. In addition, C in C/O indicates carbon in the carbon-containing agglomerates, and O indicates the oxygen to be reduced in the carbon-containing agglomerates. C/O indicates the molar ratio of these. In addition, the particle size of the carbon-containing agglomerates is not particularly limited, and may be the same as that of conventional carbon-containing agglomerates. For example, the particle size of the carbon-containing agglomerates may be about 5 to 15 mm. The particle size of the carbon-containing agglomerates can be classified using sieves with different mesh sizes. The particle size of the carbon-containing agglomerates that fall through a sieve with 15 mm mesh and remain on a sieve with 5 mm mesh is within the range of 5 to 15 mm.
＜２．含炭塊成鉱の製造方法＞
次に、本実施形態に係る含炭塊成鉱の製造方法について説明する。製造方法自体は特に制限されず、含炭塊成鉱が上述した条件を満たすように各原料を配合し、成型すればよい。
<2. Manufacturing method of carbon-containing agglomerates>
Next, a method for producing the carbon-containing agglomerates according to the present embodiment will be described. The production method itself is not particularly limited, and it is sufficient to blend and mold the raw materials so that the carbon-containing agglomerates satisfy the above-mentioned conditions.
含炭塊成鉱を製造するための原料としては、酸化鉄原料、炭材、バインダ等が挙げられる。酸化鉄原料の種類は問われず、従来の含炭塊成鉱に使用される酸化鉄原料を特に制限なく使用することができる。酸化鉄原料の例としては、表１に示す組成の転炉ダスト、高炉１次灰、焼結ダスト等が挙げられる。表１中の各数値は酸化鉄原料の総質量に対する各成分の質量％である。また、表１中の「Ｔ．Ｆｅ」は金属鉄、酸化鉄を含む全鉄を意味し、「Ｔ．Ｃ」は酸化鉄原料に含まれるカーボンを意味する。複数種類の酸化鉄原料を混合して使用してもよいし、いずれかの酸化鉄原料を単独で使用してもよい。ただし、本実施形態では、含炭塊成鉱に金属鉄を配合する必要があるので、少なくとも金属鉄を含有する酸化鉄原料を使用する必要がある。この点、表１に示す高炉１次灰は金属鉄を５０質量％以上含むので、本実施形態に係る含炭塊成鉱を製造するための酸化鉄原料として好適である。つまり、金属鉄を５０質量％以上含む酸化鉄原料を使用することで、金属鉄とカーボンの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）の調整が容易になる。また、金属鉄分が不足する場合、別途還元鉄粉やスクラップなどの金属鉄源を購入し、それを適宜使用してもよい。ただし、省資源、リサイクルの観点からは、なるべく金属鉄源を使用せず、転炉ダスト、高炉１次灰、焼結ダスト等を使用することが好ましい。 Examples of raw materials for producing carbon-containing agglomerates include iron oxide raw materials, carbonaceous materials, binders, etc. The type of iron oxide raw material is not limited, and iron oxide raw materials used in conventional carbon-containing agglomerates can be used without any particular restrictions. Examples of iron oxide raw materials include converter dust, blast furnace primary ash, sintered dust, etc., with compositions shown in Table 1. Each value in Table 1 is the mass% of each component with respect to the total mass of the iron oxide raw material. In addition, "T.Fe" in Table 1 means total iron including metallic iron and iron oxide, and "T.C" means carbon contained in the iron oxide raw material. A mixture of multiple types of iron oxide raw materials may be used, or any of the iron oxide raw materials may be used alone. However, in this embodiment, since it is necessary to blend metallic iron with the carbon-containing agglomerates, it is necessary to use an iron oxide raw material containing at least metallic iron. In this regard, the blast furnace primary ash shown in Table 1 contains 50 mass% or more of metallic iron, and is therefore suitable as an iron oxide raw material for producing carbon-containing agglomerates according to this embodiment. In other words, by using an iron oxide raw material containing 50% or more by mass of metallic iron, it becomes easier to adjust the mass ratio of metallic iron to carbon (M.Fe/T.C). Also, if there is a shortage of metallic iron, a metallic iron source such as reduced iron powder or scrap may be purchased separately and used as appropriate. However, from the standpoint of resource conservation and recycling, it is preferable to avoid using metallic iron sources as much as possible and to use converter dust, primary blast furnace ash, sintered dust, etc.
含炭塊成鉱の原料となる炭材の種類も特に制限されず、従来の含炭塊成鉱に使用される炭材を本実施形態でも好適に使用することができる。例えば、炭材としては、コークス、石炭、無煙炭、コークスダスト（コークスの製造過程で生じるダスト）、石炭チャー等が挙げられる。 The type of carbonaceous material used as the raw material for the carbon-containing agglomerated ore is not particularly limited, and carbonaceous materials used in conventional carbonaceous agglomerated ores can be suitably used in this embodiment. For example, carbonaceous materials include coke, coal, anthracite, coke dust (dust generated during the coke manufacturing process), coal char, etc.
含炭塊成鉱の原料となるバインダの種類も特に制限されず、従来の含炭塊成鉱に使用されるバインダを本実施形態でも好適に使用することができる。例えば、バインダとしては、水硬性バインダ、より具体的にはセメント（早強ポルトランドセメント等）が挙げられる。 There is no particular restriction on the type of binder used as the raw material for the carbon-containing agglomerates, and binders used in conventional carbon-containing agglomerates can be suitably used in this embodiment. For example, examples of binders include hydraulic binders, more specifically, cement (high-early-strength Portland cement, etc.).
各原料の成分は、一般的な化学分析法あるは蛍光Ｘ線分析法によって特定することができる。そこで、各原料を含炭塊成鉱が上述した条件を満たすように配合し、成型すればよい。例えば、配合原料及び適量の水分をペレタイザー、ブリケットマシーン等の造粒機で混錬及び成型した後、養生する（バインダを硬化させる）ことで含炭塊成鉱とすればよい。 The components of each raw material can be identified by general chemical analysis or X-ray fluorescence analysis. The raw materials are then mixed and molded so that the carbon-containing agglomerates satisfy the above-mentioned conditions. For example, the mixed raw materials and an appropriate amount of water can be mixed and molded in a granulator such as a pelletizer or briquette machine, and then cured (to harden the binder) to produce the carbon-containing agglomerates.
＜３．高炉の操業方法＞
つぎに、本実施形態に係る高炉の操業方法について説明する。本実施形態では、鉄系原料（焼結鉱等）の一部を本実施形態に係る含炭塊成鉱に代替して高炉の操業を行う。ここで、含炭塊成鉱由来のカーボン原単位を５～３０ｋｇ／ｔ－ＨＭとすることが好ましい。この場合、還元材比がより低減する。含炭塊成鉱由来のカーボン原単位が５ｋｇ／ｔ－ＨＭ未満では、還元材比を十分に低減することができない場合がある。一方、含炭塊成鉱由来のカーボン原単位が３０ｋｇ／ｔ－ＨＭを超えた場合、還元材比の改善効果が飽和する。上記以外の操業は従来の高炉の操業方法と同様に行えばよい。
<3. Blast furnace operation method>
Next, a method for operating a blast furnace according to the present embodiment will be described. In the present embodiment, a part of the iron-based raw material (sintered ore, etc.) is replaced with the carbon-containing agglomerated ore according to the present embodiment to operate the blast furnace. Here, it is preferable that the carbon consumption unit derived from the carbon-containing agglomerated ore is 5 to 30 kg/t-HM. In this case, the reducing agent ratio is further reduced. If the carbon consumption unit derived from the carbon-containing agglomerated ore is less than 5 kg/t-HM, the reducing agent ratio may not be sufficiently reduced. On the other hand, if the carbon consumption unit derived from the carbon-containing agglomerated ore exceeds 30 kg/t-HM, the effect of improving the reducing agent ratio becomes saturated. The operation other than the above may be performed in the same manner as the conventional blast furnace operation method.
次に、本実施形態の実施例を説明する。本実施例では、本実施形態の効果を検証するために、以下の試験を行った。もちろん、本発明は以下に説明する実施例に限定されない。本発明の属する技術の分野における通常の知識を有する者であれば、特許請求の範囲に記載された技術的思想の範疇内において、各種の変更例または修正例に想到し得ることは明らかであり、これらについても、当然に本発明の技術的範囲に属するものと了解される。 Next, an example of this embodiment will be described. In this example, the following tests were performed to verify the effects of this embodiment. Of course, the present invention is not limited to the examples described below. It is clear that a person with ordinary knowledge in the technical field to which this invention pertains can come up with various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of this invention.
まず、表１に示す酸化鉄原料、実機コークスダスト、試薬鉄粉(純度９８％）、及び早強ポルトランドセメントを準備した。酸化鉄原料、実機コークスダストの成分は蛍光Ｘ線分析法で特定した。また、各原料の粒度はｄ５０（体積基準）で５０μｍ、５３μｍ、５０μｍ、１３μｍであった。ここで、各原料のｄ５０はレーザー回折式粒度分布測定装置を用いた以下の測定方法によって測定した。すなわち、測定対象となる試料を水でスラリー化し、分散剤としてヘキサメタりん酸ナトリウム溶液を少量添加した。ついで、混合液の撹拌及び超音波照射により混合液中に試料を分散させた。ついで、この混合液をレーザー回折式粒度分布測定装置にセットし、粒度分布を測定し、ｄ５０を特定した。 First, the iron oxide raw material, actual coke dust, reagent iron powder (purity 98%), and high-early-strength Portland cement shown in Table 1 were prepared. The components of the iron oxide raw material and actual coke dust were identified by fluorescent X-ray analysis. The particle sizes of the raw materials were 50 μm, 53 μm, 50 μm, and 13 μm in terms of d50 (volume basis). The d50 of each raw material was measured by the following measurement method using a laser diffraction particle size distribution measuring device. That is, the sample to be measured was slurried with water, and a small amount of sodium hexametaphosphate solution was added as a dispersant. The sample was then dispersed in the mixed liquid by stirring and irradiating it with ultrasonic waves. The mixed liquid was then set in the laser diffraction particle size distribution measuring device, the particle size distribution was measured, and the d50 was identified.
ついで、これらの原料を適量の水と共に配合した後、ブリケットマシーンで成型した。ついで、成型した造粒物を養生した。以上の工程を酸化鉄原料の種類、各原料の配合比を変更して繰り返し行うことで、表２に示す組成の含炭塊成鉱（試験例Ｎｏ．１～２２）を作製した。作製された含炭塊成鉱のうち、粒度が８～１３ｍｍのもの（目開き１３ｍｍの篩から落ち、目開き８ｍｍの篩に残ったもの）を以下のＢＩＳ炉試験に使用した。 These raw materials were then mixed with an appropriate amount of water and molded in a briquette machine. The molded granules were then cured. The above process was repeated while changing the type of iron oxide raw material and the mixing ratio of each raw material to produce carbon-containing agglomerates (Test Examples No. 1 to 22) with the composition shown in Table 2. Of the produced carbon-containing agglomerates, those with particle sizes of 8 to 13 mm (those that fell through a 13 mm sieve and remained on a 8 mm sieve) were used in the following BIS furnace test.
表２中の各成分は、含炭塊成鉱中の各成分の質量％、モル比、原単位等を示す。例えば、「Ｔ．Ｆｅ」は含炭塊成鉱中の全鉄の質量％を示し、「Ｍ．Ｆｅ」は含炭塊成鉱中の金属鉄の質量％を示し、「Ｔ．Ｃ」は含炭塊成鉱中のカーボン含有量（質量％）を示す。「ＦｅＯ」及び「Ｆｅ２Ｏ３」は、含炭塊成鉱中の「酸化鉄」の含有量（質量％）を示す。「被還元酸素量」は、「酸化鉄」に結合した酸素の質量％を示す。「Ｃ＋Ｍ．Ｆｅ＋ＦｅＯ＋Ｆｅ２Ｏ３」は、含炭塊成鉱中のカーボン、金属鉄、及び酸化鉄の合計の質量％を示す。各成分の質量％は、含炭塊成鉱の試料の総質量に対する質量％である。「Ｍ．Ｆｅ／Ｔ．Ｃ」は含炭塊成鉱中の金属鉄とカーボンの質量比を示し、Ｃ／Ｏは含炭塊成鉱中のカーボンと被還元酸素のモル比を示す。 Each component in Table 2 indicates the mass %, molar ratio, unit of content, etc., of each component in the carbon-containing agglomerates. For example, "T.Fe" indicates the mass % of the total iron in the carbon-containing agglomerates, "M.Fe" indicates the mass % of metallic iron in the carbon-containing agglomerates, and "T.C" indicates the carbon content (mass %) in the carbon-containing agglomerates. "FeO" and " Fe2O3 " indicate the content (mass %) of "iron oxide" in the carbon-containing agglomerates. "Amount of reduced oxygen" indicates the mass % of oxygen bonded to "iron oxide ". "C+M.Fe+FeO+ Fe2O3 " indicates the total mass % of carbon, metallic iron, and iron oxide in the carbon-containing agglomerates. The mass % of each component is the mass % with respect to the total mass of the carbon-containing agglomerates sample. "M.Fe/T.C" indicates the mass ratio of metallic iron to carbon in the carbon-containing agglomerates, and "C/O" indicates the molar ratio of carbon to reduced oxygen in the carbon-containing agglomerates.
ついで、ＢＩＳ炉試験を行った。なお、ＢＩＳ炉試験の詳細は「内藤ほか：鉄と鋼、８７巻（２００１年）、Ｎｏ．５、Ｐ．３５７－３６４）」に記載された通りであり、本試験もこの非特許文献に記載された方法に従って行った。具体的には、装入チャージ当りのＴ．Ｃ、Ｔ．Ｆｅ（ここでのＴ．Ｃ、Ｔ．Ｆｅは、装入チャージ全体の総質量に対する装入チャージ内のカーボンの質量％、全鉄の質量％を示す）が一定となるように焼結鉱量、コークス量をそれぞれ調整した。 Next, a BIS furnace test was conducted. Details of the BIS furnace test are as described in "Naito et al.: Tetsu to Hagane, Vol. 87 (2001), No. 5, pp. 357-364," and this test was also conducted according to the method described in this non-patent document. Specifically, the amount of sintered ore and the amount of coke were adjusted so that the T.C and T.Fe per charge (here, T.C and T.Fe indicate the mass% of carbon and the mass% of total iron in the charge relative to the total mass of the entire charge) were constant.
また、含炭塊成鉱由来のカーボン原単位が表２に示す値となるように含炭塊成鉱の使用量を調整した。すなわち、Ｔ.Ｃが１５．０質量％の含炭塊成鉱を使用する場合、含炭塊成鉱の使用量（原単位）を１３３ｋｇ/ｔ－ＨＭとし、Ｔ.Ｃが２５．０質量％の含炭塊成鉱を使用する場合、含炭塊成鉱の使用量（原単位）を８０ｋｇ/ｔ－ＨＭとした。さらに、還元材比が４８１ｋｇ／ｔ－ＨＭ、コークス比が３４９ｋｇ／ｔ－ＨＭとなるように、送風温度１１７８℃、送風湿分１８．６ｇ／Ｎｍ３、酸素富化率２．７％の下でボッシュガス組成（ＣＯ：３６．０体積％、Ｈ２：７．０体積％、Ｎ２：５７．０体積％）と送風量（１３４３Ｎｍ３／ｔ－ＨＭ）を設定した。 The amount of carbon-containing agglomerates used was adjusted so that the carbon consumption rate derived from the carbon-containing agglomerates was the value shown in Table 2. That is, when carbon-containing agglomerates with a T.C. of 15.0 mass% were used, the amount of carbon-containing agglomerates used (consumption rate) was 133 kg/t-HM, and when carbon-containing agglomerates with a T.C. of 25.0 mass% were used, the amount of carbon-containing agglomerates used (consumption rate) was 80 kg/t-HM. Furthermore, the bosh gas composition (CO: 36.0 vol%, H2: 7.0 vol%, N2 : 57.0 vol%) and blast rate (1343 Nm3/t-HM) were set at a blast temperature of 1178°C, a blast moisture content of 18.6 g/ Nm3 , and an oxygen enrichment rate of 2.7% so that the reducing agent rate was 481 kg /t- HM and the coke rate was 349 kg/t-HM.
ここで、酸素富化率は、概略的には、熱風の総体積に対する熱風中の酸素の体積割合であり、酸素富化率（％）＝｛（空気の送風量（流量）［Ｎｍ３／ｍｉｎ］×０．２１＋酸素富化量［Ｎｍ３／ｍｉｎ］）／（空気の送風量［Ｎｍ３／ｍｉｎ］＋酸素富化量［Ｎｍ３／ｍｉｎ］）｝×１００－２１であらわされる。また、Ｏｒｅ／Ｃｏｋｅ（焼結鉱とコークスの質量比）は４．６３とした。 Here, the oxygen enrichment rate is roughly the volume ratio of oxygen in the hot air to the total volume of the hot air, and is expressed as follows: Oxygen enrichment rate (%) = {(Air blowing rate (flow rate) [Nm3/min] x 0.21 + Oxygen enrichment amount [ Nm3 /min])/(Air blowing rate [ Nm3 /min] + Oxygen enrichment amount [ Nm3 /min])} x 100 - 21. In addition, Ore/Coke (mass ratio of sintered ore to coke) was set to 4.63.
また、高炉内のアルカリ循環を考慮して、試薬ＫＯＨを、コークスに対して１．８質量％のＫ量となるように添加した。ＢＩＳ炉で得られるシャフト効率をもとに、熱物質収支を取って、還元材比を評価した。この際に、還元材比は、熱風と共に吹き込まれる微粉炭＋コークス＋含炭塊成鉱中の炭材（ここでは実機コークスダスト）をコークス相当量に補正した量の原単位として評価した。また、含炭塊成鉱中のＭ．Ｆｅによる被還元酸素減少の効果は、還元ガス量を変更せず、実験データをヘマタイト補正することで間接的に評価した。つまり、Ｍ．Ｆｅには被還元酸素が結合していないので、Ｍ．Ｆｅの分だけ還元ガス量を減らす操業を行えば、装入チャージ中のＭ．Ｆｅが多いほどより少ない還元材で多くの還元鉄が見かけ上製造されることになる。しかし、本実施形態が得るべき効果は、Ｍ．Ｆｅに結合する酸素が存在しないことによる還元材比の低下ではなく、Ｍ．Ｆｅによる触媒作用による還元材比の低下である。そこで、本実施形態では、還元ガス量を減らさずにＢＩＳ試験を実施し、得られた結果をＭ．Ｆｅがすべてヘマタイトである状態に補正し、還元材比を評価した。また、比較のために、含炭塊成鉱を使用しないベース操業（図２の点Ｐ３０に相当する操業）も行った。 In addition, in consideration of the alkali circulation in the blast furnace, the reagent KOH was added so that the K content was 1.8 mass% relative to the coke. Based on the shaft efficiency obtained in the BIS furnace, the heat and mass balance was taken to evaluate the reducing agent ratio. In this case, the reducing agent ratio was evaluated as the unit of the amount of pulverized coal + coke + carbonaceous material in the carbon-containing agglomerated ore (here, the actual coke dust) blown in with the hot air, corrected to the amount of coke. In addition, the effect of reducing the amount of oxygen to be reduced by M.Fe in the carbon-containing agglomerated ore was indirectly evaluated by correcting the experimental data for hematite without changing the amount of reducing gas. In other words, since no oxygen to be reduced is bonded to M.Fe, if an operation is performed to reduce the amount of reducing gas by the amount of M.Fe, the more M.Fe in the charging charge, the more reduced iron will be produced with less reducing agent. However, the effect to be obtained by this embodiment is not the reduction in the reducing agent ratio due to the absence of oxygen to be bonded to M.Fe, but the reduction in the reducing agent ratio due to the catalytic action of M.Fe. Therefore, in this embodiment, the BIS test was performed without reducing the amount of reducing gas, and the obtained results were corrected to a state in which all M.Fe was hematite, and the reducing agent ratio was evaluated. For comparison, a base operation (operation corresponding to point P30 in Figure 2) in which no carbon-containing agglomerates were used was also performed.
結果を表２及び図２に示す。なお、図２は上述したように含炭塊成鉱由来のカーボン原単位が２０ｋｇ／ｔ－ＨＭとなる際のデータをまとめたものである。表２の試験例Ｎｏ．１～６は、含炭塊成鉱に含まれるカーボンの含有量（Ｔ．Ｃ）を１５質量％とした例であり、試験例Ｎｏ．７～１２は、含炭塊成鉱に含まれるカーボンの含有量（Ｔ．Ｃ）を２５質量％とした例である。試験例Ｎｏ．１～１２では含炭塊成鉱由来のカーボン原単位を２０ｋｇ／ｔ－ＨＭで統一している。試験例Ｎｏ．１３～２２では、含炭塊成鉱に含まれるカーボンの含有量を１５質量％または２５質量％としつつ、含炭塊成鉱由来のカーボン原単位、または含炭塊成鉱中のカーボン、金属鉄、及び酸化鉄の合計の質量％を変動させた例である。 The results are shown in Table 2 and Figure 2. As mentioned above, Figure 2 summarizes the data when the carbon consumption unit derived from the carbon-containing agglomerates is 20 kg/t-HM. Test Examples No. 1 to 6 in Table 2 are examples in which the carbon content (T.C) contained in the carbon-containing agglomerates is 15 mass%, and Test Examples No. 7 to 12 are examples in which the carbon content (T.C) contained in the carbon-containing agglomerates is 25 mass%. In Test Examples No. 1 to 12, the carbon consumption unit derived from the carbon-containing agglomerates is unified at 20 kg/t-HM. Test Examples No. 13 to 22 are examples in which the carbon content contained in the carbon-containing agglomerates is 15 mass% or 25 mass%, while the carbon consumption unit derived from the carbon-containing agglomerates or the total mass% of carbon, metallic iron, and iron oxide in the carbon-containing agglomerates is changed.
まず、試験例Ｎｏ．１～６について検討すると、含炭塊成鉱が本実施形態の要件を満たし、さらに含炭塊成鉱由来のカーボン原単位を５～３０ｋｇ／ｔ－ＨＭの範囲内の２０ｋｇ／ｔ－ＨＭとした試験例Ｎｏ．３～５では極めて良好な還元材比が得られた。具体的には、還元材比が４９０ｋｇ／ｔ－ＨＭ以下となった。 First, considering test examples No. 1 to 6, the carbon-containing agglomerates satisfied the requirements of this embodiment, and test examples No. 3 to 5, in which the carbon consumption rate derived from the carbon-containing agglomerates was set to 20 kg/t-HM, within the range of 5 to 30 kg/t-HM, had an extremely good reducing agent ratio. Specifically, the reducing agent ratio was 490 kg/t-HM or less.
一方、含炭塊成鉱の他の要件を満たさない試験例Ｎｏ．１、２、６は、含炭塊成鉱に含まれるカーボンの含有量が同水準である試験例３～５に比べて還元材比が増加した。具体的には、試験例Ｎｏ．１、２では、金属鉄とカーボンの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）が０．４未満となっており、試験例Ｎｏ．６では、金属鉄とカーボンの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）が０．８を超えている。 On the other hand, in test samples No. 1, 2, and 6, which do not satisfy other requirements for carbon-containing agglomerates, the reducing agent ratio was increased compared to test samples 3 to 5, which had the same carbon content in the carbon-containing agglomerates. Specifically, in test samples No. 1 and 2, the mass ratio of metallic iron to carbon (M.Fe/T.C) was less than 0.4, while in test sample No. 6, the mass ratio of metallic iron to carbon (M.Fe/T.C) exceeded 0.8.
つぎに、試験例Ｎｏ．７～１２について検討すると、含炭塊成鉱が本実施形態の要件を満たし、さらに含炭塊成鉱由来のカーボン原単位を５～３０ｋｇ／ｔ－ＨＭの範囲内の２０ｋｇ／ｔ－ＨＭとした試験例Ｎｏ．９～１１では極めて良好な還元材比が得られた。具体的には、還元材比が４８０ｋｇ／ｔ－ＨＭ以下となった。 Next, when considering test examples No. 7 to 12, the carbon-containing agglomerates satisfied the requirements of this embodiment, and in test examples No. 9 to 11, in which the carbon consumption rate derived from the carbon-containing agglomerates was set to 20 kg/t-HM, within the range of 5 to 30 kg/t-HM, an extremely good reducing agent ratio was obtained. Specifically, the reducing agent ratio was 480 kg/t-HM or less.
一方、含炭塊成鉱の他の要件を満たさない試験例Ｎｏ．７、８、１２は、含炭塊成鉱に含まれるカーボンの含有量が同水準である試験例７～１２に比べて還元材比が増加した。具体的には、試験例Ｎｏ．７、８では、金属鉄とカーボンの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）が０．４未満となっており、試験例Ｎｏ．１２では、金属鉄とカーボンの質量比（Ｍ．Ｆｅ／Ｔ．Ｃ）が０．８を超えている。 On the other hand, in test samples No. 7, 8, and 12, which do not satisfy other requirements for carbon-containing agglomerates, the reducing agent ratio was increased compared to test samples 7 to 12, which had the same carbon content in the carbon-containing agglomerates. Specifically, in test samples No. 7 and 8, the mass ratio of metallic iron to carbon (M.Fe/T.C) was less than 0.4, while in test sample No. 12, the mass ratio of metallic iron to carbon (M.Fe/T.C) exceeded 0.8.
つぎに、試験例Ｎｏ．１３～１６について検討する。試験例Ｎｏ．１３～１６は、試験例Ｎｏ．４において含炭塊成鉱由来のカーボン原単位を変動させたものである。具体的には、試験例Ｎｏ．１３では、含炭塊成鉱由来のカーボン原単位が５ｋｇ／ｔ－ＨＭ未満となっている。含炭塊成鉱に含まれるカーボンの含有量が同水準である試験例Ｎｏ．１、２、６と比べると試験例Ｎｏ．１３でも還元材比の低減効果が得られたが、試験例Ｎｏ．３～５に比べると還元材比が若干増加した。 Next, test examples No. 13 to 16 will be considered. Test examples No. 13 to 16 are test examples No. 4 in which the carbon consumption unit derived from the carbon-containing agglomerates was changed. Specifically, in test example No. 13, the carbon consumption unit derived from the carbon-containing agglomerates was less than 5 kg/t-HM. Compared to test examples No. 1, 2, and 6, which have the same carbon content in the carbon-containing agglomerates, test example No. 13 also had a reduced reducing agent ratio effect, but compared to test examples No. 3 to 5, the reducing agent ratio was slightly increased.
試験例Ｎｏ．１４、１５は、試験例Ｎｏ．４において含炭塊成鉱由来のカーボン原単位を本実施形態の境界値である５ｋｇ／ｔ－ＨＭまたは３０ｋｇ／ｔ－ＨＭとしたものである。試験例Ｎｏ．１４、１５では含炭塊成鉱に含まれるカーボンの含有量が同水準である試験例Ｎｏ．３～５と同様の結果が得られた。 Test Examples No. 14 and 15 are the same as Test Example No. 4 except that the carbon consumption unit derived from the carbon-containing agglomerates is set to 5 kg/t-HM or 30 kg/t-HM, which are the boundary values of this embodiment. Test Examples No. 14 and 15 obtained results similar to those of Test Examples No. 3 to 5, which have the same carbon content in the carbon-containing agglomerates.
試験例Ｎｏ．１６では、含炭塊成鉱由来のカーボン原単位が３０ｋｇ／ｔ－ＨＭ超となっている。含炭塊成鉱に含まれるカーボンの含有量が同水準である試験例Ｎｏ．１、２、６と比べると試験例Ｎｏ．１６でも還元材比の低減効果が得られたが、試験例Ｎｏ．３～５に比べると還元材比が若干増加した。なお、この場合、還元材比の低減効果が飽和して４８５ｋｇ／ｔ－ＨＭとなった。しかし、含炭塊成鉱の熱間粉化量が増大し、シャフト部の通気抵抗が上昇したので、通気抵抗を一定とするためにコークス比を上昇させた結果、最終的にＲＡＲは４９５ｋｇ／ｔ－ＨＭとなった。 In test example No. 16, the carbon consumption rate derived from the carbon-containing agglomerates exceeded 30 kg/t-HM. Compared to test examples No. 1, 2, and 6, which had the same carbon content in the carbon-containing agglomerates, test example No. 16 also had a reducing agent rate reduction effect, but the reducing agent rate was slightly higher than in test examples No. 3 to 5. In this case, the reducing agent rate reduction effect was saturated at 485 kg/t-HM. However, the amount of hot powdering of the carbon-containing agglomerates increased, and the airflow resistance of the shaft increased, so the coke rate was increased to keep the airflow resistance constant, and the final RAR was 495 kg/t-HM.
つぎに、試験例Ｎｏ．１７～２０について検討する。試験例Ｎｏ．１７～２０は、試験例Ｎｏ．１０において含炭塊成鉱由来のカーボン原単位を変動させたものである。具体的には、試験例Ｎｏ．１７では、含炭塊成鉱由来のカーボン原単位が５ｋｇ／ｔ－ＨＭ未満となっている。含炭塊成鉱に含まれるカーボンの含有量が同水準である試験例Ｎｏ．７、８、１２と比べると試験例Ｎｏ．１７でも還元材比の低減効果が得られたが、試験例Ｎｏ．９～１１に比べると還元材比が若干増加した。 Next, test examples No. 17 to 20 will be considered. Test examples No. 17 to 20 are test examples No. 10 in which the carbon consumption rate derived from the carbon-containing agglomerates was varied. Specifically, in test example No. 17, the carbon consumption rate derived from the carbon-containing agglomerates was less than 5 kg/t-HM. Compared to test examples No. 7, 8, and 12, which had the same carbon content in the carbon-containing agglomerates, test example No. 17 also had the effect of reducing the reducing agent ratio, but compared to test examples No. 9 to 11, the reducing agent ratio was slightly increased.
試験例Ｎｏ．１８、１９は、試験例Ｎｏ．１０において含炭塊成鉱由来のカーボン原単位を本実施形態の境界値である５ｋｇ／ｔ－ＨＭまたは３０ｋｇ／ｔ－ＨＭとしたものである。試験例Ｎｏ．１８、１９では含炭塊成鉱に含まれるカーボンの含有量が同水準である試験例Ｎｏ．９～１１と同様の結果が得られた。 Test Examples No. 18 and 19 are the same as Test Example No. 10 except that the carbon consumption rate derived from the carbon-containing agglomerates is set to 5 kg/t-HM or 30 kg/t-HM, which are the boundary values of this embodiment. Test Examples No. 18 and 19 obtained results similar to those of Test Examples No. 9 to 11, which have the same carbon content in the carbon-containing agglomerates.
試験例Ｎｏ．２０では、含炭塊成鉱由来のカーボン原単位が３０ｋｇ／ｔ－ＨＭ超となっている。含炭塊成鉱に含まれるカーボンの含有量が同水準である試験例Ｎｏ．７、８、１２と比べると試験例Ｎｏ．２０でも還元材比の低減効果が得られたが、試験例Ｎｏ．９～１１に比べると還元材比が若干増加した。なお、この場合、還元材比の低減効果が飽和して４７５ｋｇ／ｔ－ＨＭとなった。しかし、含炭塊成鉱の熱間粉化量が増大し、シャフト部の通気抵抗が上昇したので、通気抵抗を一定とするためにコークス比を上昇させた結果、最終的にＲＡＲは４８２ｋｇ／ｔ－ＨＭとなった。 In test example No. 20, the carbon consumption rate derived from the carbon-containing agglomerates exceeded 30 kg/t-HM. Compared to test examples No. 7, 8, and 12, which had the same carbon content in the carbon-containing agglomerates, test example No. 20 also had a reducing agent rate reduction effect, but compared to test examples No. 9 to 11, the reducing agent rate increased slightly. In this case, the reducing agent rate reduction effect saturated at 475 kg/t-HM. However, the amount of hot powdering of the carbon-containing agglomerates increased, and the airflow resistance of the shaft increased, so the coke rate was increased to keep the airflow resistance constant, and the final RAR became 482 kg/t-HM.
試験例Ｎｏ．２１、２２では、カーボン、金属鉄、及び酸化鉄を合計で７０質量％未満となっている。このため、還元材比が十分に低減しなかった。 In test examples No. 21 and 22, the total amount of carbon, metallic iron, and iron oxide was less than 70 mass %. Therefore, the reducing agent ratio was not sufficiently reduced.
試験例２３は、試験例Ｎｏ．４において含炭塊成鉱のカーボン含有量を変動させたものである。具体的には、含炭塊成鉱のカーボン含有量が１５％未満となっている。Ｃ／Ｏが十分高くないので、試験例Ｎｏ．４に比べると還元材比が増加した。 Test Example 23 is the same as Test Example No. 4 except that the carbon content of the carbon-containing agglomerates is changed. Specifically, the carbon content of the carbon-containing agglomerates is less than 15%. Since the C/O ratio is not high enough, the reducing agent ratio is increased compared to Test Example No. 4.
試験例２４は、試験例Ｎｏ．１０において含炭塊成鉱のカーボン含有量を変動させたものである。具体的には、含炭塊成鉱のカーボン含有量が２５％超となっている。Ｃ／Ｏが過剰に高く、効率良く効果が発現しないのに加えて、含炭塊成鉱の炉内粉化が著しくなり高炉操業が不安定化したため、試験例Ｎｏ．１０に比べると還元材比が増加した。 Test Example 24 is an example of Test Example No. 10 in which the carbon content of the carbon-containing agglomerates was changed. Specifically, the carbon content of the carbon-containing agglomerates was over 25%. The C/O ratio was excessively high, and in addition to the inefficient effect, the carbon-containing agglomerates were significantly pulverized in the furnace, destabilizing blast furnace operation, and the reducing agent ratio was increased compared to Test Example No. 10.
以上、添付図面を参照しながら本発明の好適な実施形態について詳細に説明したが、本発明はかかる例に限定されない。本発明の属する技術の分野における通常の知識を有する者であれば、特許請求の範囲に記載された技術的思想の範疇内において、各種の変更例または修正例に想到し得ることは明らかであり、これらについても、当然に本発明の技術的範囲に属するものと了解される。 The above describes in detail preferred embodiments of the present invention with reference to the attached drawings, but the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.
Claims (2)
前記カーボンの含有量が前記高炉用含炭塊成鉱の総質量に対して１５～２５質量％であり、
前記金属鉄と前記カーボンの質量比が０．４～０．８であることを特徴とする、高炉用含炭塊成鉱。 A carbon-containing agglomerate for blast furnaces containing 70% by mass or more of carbon, metallic iron, and iron oxide in total,
The carbon content is 15 to 25 mass% based on the total mass of the carbon-containing agglomerate for blast furnace,
A carbon-containing agglomerate for blast furnaces, characterized in that a mass ratio of the metallic iron to the carbon is 0.4 to 0.8.
前記高炉用含炭塊成鉱由来のカーボン原単位を５～３０ｋｇ／ｔ－ＨＭとすることを特徴とする、高炉の操業方法。 A method for operating a blast furnace using the carbon-containing agglomerate ore according to claim 1,
The method for operating a blast furnace is characterized in that the carbon consumption rate derived from the carbon-containing agglomerated ore for blast furnace is 5 to 30 kg/t-HM.
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| JP2011225926A (en) | 2010-04-19 | 2011-11-10 | Jfe Steel Corp | Agglomerated ore including carbonaceous material for iron-making, and producing method therefor |
| JP2014205895A (en) | 2013-04-15 | 2014-10-30 | 新日鐵住金株式会社 | Blast furnace operation method |
| WO2014190391A1 (en) | 2013-08-19 | 2014-12-04 | Gomez Rodolfo Antonio M | A process for producing and reducing an iron oxide briquette |
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| JP2011225926A (en) | 2010-04-19 | 2011-11-10 | Jfe Steel Corp | Agglomerated ore including carbonaceous material for iron-making, and producing method therefor |
| JP2014205895A (en) | 2013-04-15 | 2014-10-30 | 新日鐵住金株式会社 | Blast furnace operation method |
| WO2014190391A1 (en) | 2013-08-19 | 2014-12-04 | Gomez Rodolfo Antonio M | A process for producing and reducing an iron oxide briquette |
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