JP6638764B2 - Blast furnace operation method - Google Patents
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- 238000000034 method Methods 0.000 title claims description 20
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Description
本発明は、フェロコークスと炭材内装鉱とを、高炉原料として併用する高炉の操業方法に関する。 The present invention relates to a method for operating a blast furnace in which ferrocoke and a carbonaceous material-containing ore are used in combination as blast furnace raw materials.
高炉では、通常、鉱石原料である鉄鉱石（単に、「鉱石」とも記す）と、還元材であるコークスとを、それぞれが交互に層状となるように炉頂から装入し、高炉内に鉱石層とコークス層とを形成している。そして、炉内における鉱石層とコークス層との堆積後の分布を調整することにより、炉内でのガスの流れを制御している。 In a blast furnace, iron ore as an ore raw material (also simply referred to as “ore”) and coke as a reducing agent are usually charged from the furnace top in a layered manner, and the ore is introduced into the blast furnace. And a coke layer. The gas flow in the furnace is controlled by adjusting the distribution of the ore layer and the coke layer in the furnace after the deposition.
この高炉における還元材比を低下させるためには、コークスなどの炭材と鉄鉱石とを近接配置させ、高炉の熱保存帯の温度を低下させることが有効であり、古くは、コークスを鉱石層に混合して装入する混合装入技術に始まり、近年では、単一粒子内に炭材と鉄鉱石の両方を含む塊成化物を用いることで、更に、近接距離を短くしたコンポジット原料の開発が進んでいる。ここで、「還元材比」とは、還元材の種類にかかわらず、溶銑１トンを製造するのに必要な還元材（コークス、微粉炭など）の質量合計であり、「ｋｇ／溶銑−ｔ」で表示される。 In order to lower the reducing agent ratio in this blast furnace, it is effective to arrange a carbon material such as coke and iron ore close to each other to lower the temperature of the heat preservation zone of the blast furnace. In recent years, the development of composite raw materials has been shortened by using agglomerates containing both carbonaceous materials and iron ore in a single particle. Is progressing. Here, the “reducing material ratio” is the total mass of the reducing material (coke, pulverized coal, etc.) necessary to produce one ton of hot metal, regardless of the type of the reducing material, and “kg / hot metal−t Is displayed.
このコンポジット原料のうち、炭材主体のものをフェロコークスといい、鉄鉱石主体のものを炭材内装鉱といい、それぞれ、製造方法は異なるが、発現する効果は類似している。即ち、フェロコークスは、下記の（１）式の反応によってＣＯガスを発生し、炭材内装鉱は、下記の（２）式の反応によってＣＯガスを発生し、発生するＣＯガスによる間接還元反応を促進させて還元材比を低下させている。ここで、フェロコークスとは、石炭と鉄鉱石との混合物を成型し乾留して製造された、コークス中に金属鉄が混在する塊成化物であり、炭材内装鉱とは、微粉状の炭材と鉄鉱石とを混合して熱間成形または冷間成型した塊成化物、或いは、炭材核の周囲に鉄鉱石粉を被覆させて造粒し、焼結機で焼成した塊成化物である。 Among these composite raw materials, those mainly composed of carbon materials are called ferro-coke, and those mainly composed of iron ores are called carbon material interior ores. The production methods are different, but the manifested effects are similar. That is, ferro-coke generates CO gas by the reaction of the following formula (1), and the carbonaceous material-containing ore generates CO gas by the reaction of the following formula (2), and the indirect reduction reaction by the generated CO gas. Is promoted to reduce the reducing agent ratio. Here, ferro-coke is an agglomerate in which metallic iron is mixed in coke, which is produced by molding and carbonizing a mixture of coal and iron ore. Agglomerates formed by hot or cold forming by mixing wood and iron ore, or agglomerates formed by coating iron ore powder around carbon material cores, granulating and firing with a sintering machine .
Ｃ＋ＣＯ２→２ＣＯ………（１）
ＦｅＯＸ＋ＸＣ→Ｆｅ＋ＸＣＯ………（２）
（１）式及び（２）式の反応は、ともに吸熱反応であり、高炉の熱保存帯の温度を下げるとともに、周囲の鉱石にＣＯガスを供給し、還元反応を促進させる。
C + CO 2 → 2CO (1)
FeO X + XC → Fe + XCO (2)
The reactions of the formulas (1) and (2) are both endothermic reactions, lower the temperature of the heat storage zone of the blast furnace, and supply CO gas to surrounding ores to accelerate the reduction reaction.
フェロコークスを高炉原料として使用した高炉の操業方法として、特許文献１には、コークスは単独で装入してコークス層を形成させ、フェロコークスは鉄鉱石と混合し、鉱石層中にフェロコークスを混合する方法が提案されている。また、特許文献２には、フェロコークスを、軟化開始温度が焼結鉱よりも低い塊鉱石のような難被還元性の鉱石原料と混合して装入する方法が提案されている。 As a method of operating a blast furnace using ferro-coke as a blast furnace raw material, Patent Document 1 discloses that coke is charged alone to form a coke layer, ferro-coke is mixed with iron ore, and ferro-coke is mixed in the ore layer. Mixing methods have been proposed. Patent Literature 2 proposes a method in which ferrocoke is mixed with a hard-to-reducible ore raw material such as a lump ore having a softening start temperature lower than that of a sintered ore and charged.
また、炭材内装鉱を用いた高炉操業方法として、特許文献３には、炭材内装鉱のみからなる炭素含有原料、または、炭材内装鉱と、小粒コークス、小粒高反応性コークス、フェロコークスからなる群の少なくとも１種とからなる炭素含有原料を鉄鉱石に混合して鉱石層を形成し、且つ、前記鉱石層中における前記鉄鉱石と前記炭素含有原料との個数比が５０以下となるように調整する方法が提案されている。 Patent Literature 3 discloses a blast furnace operating method using a carbonaceous material-containing ore, a carbon-containing raw material consisting only of a carbonaceous material-containing ore, a carbonaceous material-containing ore, a small-grain coke, a small-grain highly-reactive coke, and a ferrocoke. A carbon-containing raw material comprising at least one of the group consisting of is mixed with iron ore to form an ore layer, and the number ratio between the iron ore and the carbon-containing raw material in the ore layer is 50 or less. Adjustment methods have been proposed.
しかしながら、上記従来技術には以下の問題がある。 However, the above prior art has the following problems.
即ち、特許文献１及び特許文献２に提案される方法では、フェロコークスを用いて通常の焼結鉱や難被還元性の塊鉱石を効率良く還元することはできるが、炭材内装鉱のような高被還元性原料との併用方法は提示されておらず、フェロコークス及び炭材内装鉱を併用して還元材比を更に下げていくような場合には、十分な効果は得られない。 That is, in the methods proposed in Patent Literature 1 and Patent Literature 2, ordinary sinter ores and hardly reducible lump ores can be efficiently reduced by using ferro-coke. A method of using the raw material with high reducibility is not disclosed, and when the ratio of the reducing material is further reduced by using the ferro-coke and the carbonaceous material-containing ore, a sufficient effect cannot be obtained.
特許文献３は、炭材内装鉱やフェロコークスのサイズを適正化して、これらの鉱石層内における分散性を高め、還元効率を改善する技術であるが、炭材内装鉱、小粒コークス、小粒高反応性コークス、フェロコークスのそれぞれの特性にかかわらず、これらを区別することなく扱っており、これらの適正な組合せや炉内配置については言及していない。特に、炭材内装鉱及びフェロコークスの使用量が増加した場合には、炭材内装鉱の反応及びフェロコークスの反応が相互に干渉し、効果が減少する可能性がある。 Patent Literature 3 discloses a technique for optimizing the size of a carbonaceous material ore and ferro-coke to increase the dispersibility in these ore layers and improve the reduction efficiency. Regardless of the characteristics of reactive coke and ferro-coke, they are treated without distinction, and no proper combination or arrangement in the furnace is mentioned. In particular, when the usage of the carbonaceous material ore and ferrocoke increases, the reaction of the carbonaceous material ore and the reaction of ferrocoke may interfere with each other, and the effect may be reduced.
本発明は上記事情に鑑みてなされたもので、その目的とするところは、高炉でフェロコークスと炭材内装鉱とを高炉原料として併用する際に、それぞれを適正な炉内配置位置で使用することで、相互干渉を防ぎ、還元材比を低減することのできる、高炉の操業方法を提供することである。 The present invention has been made in view of the above circumstances, and it is an object of the present invention to use ferro-coke and a carbonaceous material-containing ore as blast furnace raw materials in a blast furnace, and to use each of them in an appropriate furnace arrangement position. Accordingly, it is an object of the present invention to provide a blast furnace operating method capable of preventing mutual interference and reducing a reducing material ratio.
上記課題を解決するための本発明の要旨は以下のとおりである。
［１］高炉内にコークス層と鉱石層とを交互に形成する高炉の操業方法であって、前記鉱石層の一部に炭材内装鉱を混合して装入し、且つ、前記鉱石層の他の一部にフェロコークスを混合して装入することとし、前記鉱石層を少なくとも２バッチに分けて装入し、少なくとも一つのバッチで炭材内装鉱を混合した鉱石原料を装入し、少なくとも他の一つのバッチでフェロコークスを混合した鉱石原料を装入する、高炉の操業方法。
［２］鉱石層を少なくとも２バッチに分けて装入するにあたり、少なくとも一つのバッチで炭材内装鉱を混合した鉱石原料を装入し、その後のバッチでフェロコークスを混合した鉱石原料を装入する、上記［１］に記載の高炉の操業方法。
［３］鉱石層を少なくとも２バッチに分けて装入するにあたり、後のバッチで装入したフェロコークスを混合した鉱石原料の堆積層の頂点が、先のバッチで装入した炭材内装鉱を混合した鉱石原料の堆積層の頂点よりも高炉炉壁側に位置するように装入する、上記［２］に記載の高炉の操業方法。
The gist of the present invention for solving the above problems is as follows.
[1] A method for operating a blast furnace in which a coke layer and an ore layer are alternately formed in a blast furnace, wherein a carbonaceous material ore is mixed and charged into a part of the ore layer, and Ferro coke is mixed and charged into another part, the ore layer is charged in at least two batches, and at least one batch is charged with the ore raw material mixed with the carbonaceous material ore, A method of operating a blast furnace in which at least one other batch is charged with an ore raw material mixed with ferrocoke.
[2] When charging the ore layer in at least two batches, at least one batch is charged with the ore raw material mixed with the carbonaceous material ore, and the subsequent batch is charged with the ore raw material mixed with ferro-coke. The method for operating a blast furnace according to the above [1].
[3] In charging the ore layer in at least two batches, the top of the ore raw material mixture layer mixed with ferro-coke charged in the later batch may cause the carbonaceous material ore charged in the previous batch to be charged. The blast furnace operating method according to the above [2], wherein the mixed ore raw materials are charged so as to be located closer to the blast furnace wall than the top of the sedimentary layer.
本発明によれば、高炉においてフェロコークスと炭材内装鉱とを併用する際に、フェロコークスと炭材内装鉱とを分離して鉱石層に装入するので、双方の効果が干渉することを防止でき、従来よりも大幅に還元材比を低減することが可能になる。更に、炭材内装鉱を鉱石層の下層に配置し、フェロコークスを鉱石層の上層に配置することで、或いは、更にフェロコークスを高炉炉壁側に配置することで、フェロコークスが雰囲気中のＣＯ２ガス濃度の高い場所に配置され、更なる還元効率の改善が可能となる。 According to the present invention, when ferrocoke and carbonaceous material ore are used together in a blast furnace, ferrocoke and carbonaceous material ore are separated and charged into an ore layer, so that both effects interfere with each other. It is possible to significantly reduce the reducing agent ratio as compared with the related art. Furthermore, by arranging the carbonaceous material-containing ore in the lower layer of the ore layer and arranging ferro-coke in the upper layer of the ore layer, or further arranging ferro-coke on the blast furnace wall side, It is arranged in a place where the CO 2 gas concentration is high, and the reduction efficiency can be further improved.
以下、本発明を具体的に説明する。 Hereinafter, the present invention will be described specifically.
図１に、本発明を適用した場合の高炉装入物分布の一例の概念図を示す。図１において、符号１は、高炉中心線、２は、高炉炉壁、３は、塊コークスで形成されるコークス層、４は、炭材内装鉱を混合する鉱石層、５は、フェロコークスを混合する鉱石層、６は、炭材内装鉱、７は、フェロコークス、８は、焼結鉱である。焼結鉱８は、炭材内装鉱６を混合する鉱石層４及びフェロコークス７を混合する鉱石層５の主成分である。尚、図１では、コークス層３、炭材内装鉱６を混合する鉱石層４及びフェロコークス７を混合する鉱石層５がそれぞれ１層だけ記載されているが、実際にはこれらが交互に層状に重なり合って高炉内の装入物分布が形成されている。また、図１は鉱石原料として鉄鉱石の焼結鉱８を使用した例を示している。 FIG. 1 shows a conceptual diagram of an example of a blast furnace charge distribution when the present invention is applied. In FIG. 1, reference numeral 1 denotes a blast furnace center line, 2 denotes a blast furnace wall, 3 denotes a coke layer formed of lump coke, 4 denotes an ore layer that mixes carbonaceous material ore, and 5 denotes ferro-coke. The ore layer to be mixed, 6 is a carbonaceous material ore, 7 is ferro-coke, and 8 is a sintered ore. The sintered ore 8 is a main component of the ore layer 4 that mixes the carbonaceous material ore 6 and the ore layer 5 that mixes ferrocoke 7. In FIG. 1, only one coke layer 3, an ore layer 4 for mixing the carbonaceous material ore 6, and an ore layer 5 for mixing ferro-coke 7 are shown. , A charge distribution in the blast furnace is formed. FIG. 1 shows an example in which a sintered ore 8 of iron ore is used as an ore raw material.
本発明に係る高炉の操業方法は、高炉内にコークス層と鉱石層とを交互に形成する高炉の操業方法であって、前記鉱石層の一部に炭材内装鉱を混合して装入し、且つ、前記鉱石層の他の一部にフェロコークスを混合して装入することとし、鉱石原料である焼結鉱８の装入を少なくとも２バッチに分け、一つのバッチで炭材内装鉱６を混合した焼結鉱８を装入し、少なくとも他の一つのバッチでフェロコークス７を混合した焼結鉱８を装入する。例えば、２バッチで装入する場合には、１バッチ目に、炭材内装鉱６を混合した焼結鉱８を装入して炭材内装鉱６を混合する鉱石層４を形成し、２バッチ目に、フェロコークス７を混合した焼結鉱８を装入してフェロコークス７を混合する鉱石層５を形成する。また、逆に、１バッチ目に、フェロコークス７を混合した焼結鉱８を装入してフェロコークス７を混合する鉱石層５を形成し、２バッチ目に、炭材内装鉱６を混合した焼結鉱８を装入して炭材内装鉱６を混合する鉱石層４を形成してもよい。 The method for operating a blast furnace according to the present invention is a method for operating a blast furnace in which a coke layer and an ore layer are alternately formed in a blast furnace, wherein a carbonaceous material-containing ore is mixed and charged into a part of the ore layer. In addition, ferro-coke is mixed and charged into the other part of the ore layer, and the charging of the ore raw material 8 is divided into at least two batches. 6, and the sinter 8 mixed with the ferro-coke 7 is charged in at least one other batch. For example, in the case of charging in two batches, the first batch is charged with the sintered ore 8 mixed with the carbonaceous material ore 6 to form the ore layer 4 in which the carbonaceous material ore 6 is mixed. In the batch, the ore layer 5 mixed with the ferro-coke 7 is formed by charging the sintered ore 8 mixed with the ferro-coke 7. Conversely, in the first batch, the ore layer 5 in which the ferro-coke 7 is mixed is formed by charging the sintered ore 8 in which the ferro-coke 7 is mixed, and in the second batch, the carbonaceous material-containing ore 6 is mixed. The ore layer 4 in which the sintered ore 8 is charged and the carbonaceous material ore 6 is mixed may be formed.
本発明では、上記のように、炭材内装鉱６とフェロコークス７とを、それぞれ鉱石層４及び鉱石層５に分離して装入する。つまり、鉱石層に炭材内装鉱６とフェロコークス７とが混在しないようにするべく、鉱石層４に炭材内装鉱６を混合して装入し、且つ、鉱石層５にフェロコークス７を混合して装入する。これによって、互いの効果の干渉を防ぎ、双方の還元促進効果を最大限発現させる。 In the present invention, as described above, the carbonaceous material-containing ore 6 and the ferrocoke 7 are separately charged into the ore layer 4 and the ore layer 5, respectively. That is, in order to prevent the carbonaceous material ore 6 and the ferro-coke 7 from being mixed in the ore layer, the carbonaceous material ore 6 is mixed and charged into the ore layer 4 and the ferrocoke 7 is added to the ore layer 5. Mix and charge. This prevents interference between the effects of each other and maximizes the effect of promoting both reductions.
更に、鉱石原料である焼結鉱８を少なくとも２バッチに分けて装入するにあたり、先に装入するバッチで炭材内装鉱６を混合した焼結鉱８を装入し、その後のバッチでフェロコークス７を混合した焼結鉱８を装入し、フェロコークス７を混合した鉱石層５の堆積層の頂点が炭材内装鉱６を混合した鉱石層４の堆積層の頂点よりも高炉炉壁２側に位置するような装入物分布となるように、高炉への鉱石原料装入方法を調整することが望ましい。 Furthermore, when charging the ore raw material, the sintered ore 8 in at least two batches, the charged ore 8 in which the carbonaceous material ore 6 is mixed in the batch to be charged first is charged, and the subsequent batch is charged. The sinter ore 8 mixed with the ferro-coke 7 is charged, and the top of the sedimentary layer of the ore layer 5 mixed with the ferrocoke 7 is higher than the top of the sedimentary layer of the ore layer 4 mixed with the carbonaceous interior ore 6. It is desirable to adjust the method of charging the ore raw material into the blast furnace so that the charge distribution is located on the side of the wall 2.
また、鉱石層を３バッチに分けて、焼結鉱８のみ、炭材内装鉱６を混合した焼結鉱８、フェロコークス７を混合した焼結鉱８をそれぞれ各１バッチずつ装入した場合や、或いは、３バッチの内で２バッチを炭材内装鉱６を混合した焼結鉱８とし、残りの１バッチをフェロコークス７を混合した焼結鉱８とした場合や、３バッチの内で２バッチをフェロコークス７を混合した焼結鉱８とし、残りの１バッチを炭材内装鉱６を混合した焼結鉱８とした場合でも、同様の効果が得られる。また、各バッチを高炉の径方向に振り分けて装入した場合や、上下方向に重ねて装入した場合でも、同様の効果が得られる。 Further, when the ore layer is divided into three batches, and only the sinter 8 is charged, the sinter 8 mixed with the carbonaceous interior ore 6, and the sinter 8 mixed with the ferro-coke 7 are charged in batches. Or two of the three batches are sintered ores 8 mixed with carbonaceous material ore 6 and the remaining one is sintered ore 8 mixed with ferro-coke 7 or The same effect can be obtained when two batches are used as the sintered ore 8 in which the ferro coke 7 is mixed and the remaining one batch is used as the sintered ore 8 in which the carbonaceous material ore 6 is mixed. The same effect can be obtained even when the batches are charged in the radial direction of the blast furnace and charged in a stacked manner in the vertical direction.
鉱石層を３バッチに分ける場合でも、図２及び図３に示すように、一つのバッチで炭材内装鉱６を混合した焼結鉱８を装入した後のバッチで、フェロコークス７を混合した焼結鉱８を装入することで、効果が得られる。尚、図２及び図３は、本発明を適用した場合の高炉装入物分布の他の一例の概念図である。図２において、符号１２は、焼結鉱のみからなる鉱石層である。 Even when the ore layer is divided into three batches, as shown in FIGS. 2 and 3, the ferro-coke 7 is mixed in the batch after the sinter 8 in which the carbonaceous material-containing ore 6 is mixed in one batch. The effect can be obtained by charging the sintered ore 8 thus obtained. 2 and 3 are conceptual diagrams of another example of the blast furnace charge distribution when the present invention is applied. In FIG. 2, reference numeral 12 denotes an ore layer composed of only sintered ore.
本発明の効果を検証するにあたり、発明者らは、図４に示す竪型の反応炉を用いて、鉄鉱石の焼結鉱、フェロコークス、炭材内装鉱の混合充填層の還元試験を行った。各還元試験で用いた高炉原料は、粒径が１０〜１５ｍｍの５００ｇの焼結鉱、粒径が２０ｍｍの１６ｇのフェロコークス、粒径が１０ｍｍの２６ｇの炭材内装鉱であり、これらの高炉原料を反応炉中の反応管内の黒鉛製容器に堆積し、下方からＣＯ、ＣＯ２、Ｎ２混合ガス（Ｎ２；５０体積％）を流しながら、適宜の温度に制御した。 In verifying the effect of the present invention, the inventors conducted a reduction test of a mixed packed bed of iron ore sinter, ferro-coke, and carbonaceous material ore using a vertical reactor shown in FIG. Was. The blast furnace raw materials used in each reduction test were 500 g of sintered ore having a particle size of 10 to 15 mm, 16 g of ferro-coke having a particle size of 20 mm, and 26 g of a carbonaceous material ore having a particle size of 10 mm. The raw materials were deposited in a graphite container in a reaction tube in a reaction furnace, and controlled at an appropriate temperature while flowing a mixed gas of CO, CO 2 , and N 2 (N 2 ; 50% by volume) from below.
これらの高炉原料の充填方法として、図５に示すように、ケース１；３種類の各原料を均一に混合した場合、ケース２；焼結鉱の半分（２５０ｇ）を１６ｇのフェロコークスと混合して下層に充填し、残り半分の２５０ｇの焼結鉱を２６ｇの炭材内装鉱と混合して上層に充填した場合、ケース３；ケース２の上下を逆にして充填した場合の３水準を採用した。尚、図５において、符号９は、焼結鉱とフェロコークスと炭材内装鉱との混合充填層、１０は、焼結鉱と炭材内装鉱との混合充填層、１１は、焼結鉱とフェロコークスとの混合充填層、１３は、黒鉛製容器である。 As a method for charging these blast furnace raw materials, as shown in FIG. 5, case 1: when three types of raw materials are uniformly mixed, case 2: half of sintered ore (250 g) is mixed with 16 g of ferro-coke. Case 3; When the upper half is filled by mixing the remaining half of 250 g of sintered ore with 26 g of carbonaceous material ore and filling the upper layer, three levels are adopted when filling the case 2 upside down. did. In FIG. 5, reference numeral 9 denotes a mixed and filled layer of sintered ore, ferrocoke and carbonaceous material ore, 10 denotes a mixed and filled layer of sintered ore and carbonaceous material ore, and 11 denotes a sintered ore. And a mixed packed layer of ferrocoke and 13 is a graphite container.
試験条件は、高炉内条件を模擬するために、図６に示すように、まず、５℃／ｍｉｎで９００℃まで昇温し、次いで、２℃／ｍｉｎで１１００℃まで昇温し、その後、５℃／ｍｉｎで１２００℃まで昇温した。温度は充填層の上下方向中間位置に熱電対を設置して測定した。その際に、図７に示すように、試験初期のガス組成をＣＯ／（ＣＯ＋ＣＯ２）＝０．５から開始し、所定温度で所定のガス組成に切り替えて、１２００℃ではＣＯ／（ＣＯ＋ＣＯ２）を０．９に調整した。 As shown in FIG. 6, the test conditions were as follows. First, the temperature was raised at 5 ° C./min to 900 ° C., then at 2 ° C./min to 1100 ° C. to simulate the conditions inside the blast furnace. The temperature was raised to 1200 ° C. at 5 ° C./min. The temperature was measured by installing a thermocouple at an intermediate position in the vertical direction of the packed bed. At that time, as shown in FIG. 7, the gas composition of the test the initial starting from CO / (CO + CO 2) = 0.5, is switched to a predetermined gas composition at a predetermined temperature, at 1200 ℃ CO / (CO + CO 2 ) Was adjusted to 0.9.
１２００℃まで昇温した後に冷却し、冷却後、焼結鉱の化学分析を行い、焼結鉱の還元率を求めた。得られた還元率を図８に示す。還元率は、ケース１では６８％、ケース２では７９％、ケース３では８３％であった。 After the temperature was raised to 1200 ° C., the mixture was cooled and, after cooling, the sinter was subjected to chemical analysis to determine the reduction ratio of the sinter. FIG. 8 shows the obtained reduction ratio. The reduction rate was 68% in Case 1, 79% in Case 2, and 83% in Case 3.
即ち、焼結鉱中にフェロコークス及び炭材内装鉱を均一に混合したケース１と比べて、フェロコークス及び炭材内装鉱を分離して装入したケース２及びケース３の方が、還元率が高くなっており、特に、フェロコークスを上層に配置したケース３において高い還元率が得られた。 That is, in comparison with Case 1 in which ferrocoke and carbonaceous material-containing ore were uniformly mixed in the sinter, Cases 2 and 3 in which ferrocoke and carbonaceous material-containing ore were separately charged had a lower reduction rate. In particular, a high reduction rate was obtained in Case 3 in which ferro-coke was disposed in the upper layer.
高炉における還元材比を低下させるためには、［背景技術］の欄で説明したように、フェロコークス７や炭材内装鉱６などを高炉に添加して、高炉の熱保存帯の温度を低下させることが有効であり、その場合に、フェロコークス７は、下記の（１）式の反応によってＣＯガスを発生し、炭材内装鉱６は、下記の（２）式の反応によってＣＯガスを発生し、還元材比の低下に寄与している。 In order to lower the reducing agent ratio in the blast furnace, as described in the section of [Background Art], the temperature of the heat preservation zone of the blast furnace is reduced by adding ferro-coke 7 or carbonaceous material ore 6 to the blast furnace. In this case, it is effective that the ferro-coke 7 generates CO gas by the reaction of the following formula (1), and the carbonaceous material ore 6 generates CO gas by the reaction of the following formula (2). Occurs, contributing to a reduction in the reducing agent ratio.
Ｃ＋ＣＯ２→２ＣＯ………（１）
ＦｅＯＸ＋ＸＣ→Ｆｅ＋ＸＣＯ………（２）
フェロコークス７と炭材内装鉱６とを分離した方が焼結鉱８の還元が促進された理由は、フェロコークス７及び炭材内装鉱６を混合した場合には、（１）式のフェロコークス７の反応によって発生したＣＯガスが、下記の（３）式の反応により、炭材内装鉱６の還元に使われてしまい、フェロコークス７による周囲の焼結鉱８の還元促進効果が減少すると考えられる。
C + CO 2 → 2CO (1)
FeO X + XC → Fe + XCO (2)
The reason why the separation of the ferrocoke 7 and the carbonaceous material ore 6 promoted the reduction of the sintered ore 8 is that when the ferrocoke 7 and the carbonaceous material ore 6 were mixed, the ferro-coke 7 of the formula (1) was used. The CO gas generated by the reaction of the coke 7 is used for the reduction of the carbonaceous material-containing ore 6 by the reaction of the following formula (3), and the reduction promoting effect of the ferro-coke 7 on the surrounding sinter 8 is reduced. It is thought that.
ＦｅＯＸ＋ＸＣＯ→Ｆｅ＋ＸＣＯ２………（３）
更に、（３）式の反応によって炭材内装鉱内の鉄分の酸化度が低下すると、（２）式の反応量も減少し、その結果、炭材内装鉱６による周囲の焼結鉱８の還元促進効果も減少すると考えられる。
FeO X + XCO → Fe + XCO 2 (3)
Further, when the degree of oxidation of iron in the carbonaceous material ore is reduced by the reaction of the formula (3), the reaction amount of the formula (2) is also reduced, and as a result, the surrounding sintered ore 8 by the carbonaceous material ore 6 is reduced. It is thought that the reduction promoting effect also decreases.
このように、フェロコークス７及び炭材内装鉱６を混在させた場合には、フェロコークス７の反応及び炭材内装鉱６の反応が干渉して、周囲の焼結鉱８に対する還元促進効果が減少してしまう。したがって、本発明では、フェロコークス７と炭材内装鉱６とを分離して鉱石層に装入することとした。 As described above, when the ferrocoke 7 and the carbonaceous material ore 6 are mixed, the reaction of the ferrocoke 7 and the reaction of the carbonaceous material ore 6 interfere with each other, so that the effect of promoting reduction of the surrounding sintered ore 8 is reduced. Will decrease. Therefore, in the present invention, the ferrocoke 7 and the carbonaceous material ore 6 are separated and charged into the ore layer.
フェロコークス７と炭材内装鉱６とを分離する際には、フェロコークス７及び炭材内装鉱６のそれぞれの高炉内における配置位置が重要となる。ここで、フェロコークス７を上層に配置することで、図８のケース３の還元率の結果に示すように、高い還元促進効果が得られる。これは、層上部に行くほど、焼結鉱８の還元反応によってＣＯ２ガス濃度が増加し、そのために、フェロコークス７による（１）式の反応が加速される方向に向かうことによる。 When separating the ferrocoke 7 and the carbonaceous material-containing ore 6, the arrangement positions of the ferrocoke 7 and the carbonaceous material-containing ore 6 in the respective blast furnaces are important. Here, by arranging the ferro-coke 7 in the upper layer, a high reduction promoting effect can be obtained as shown in the result of the reduction rate of the case 3 in FIG. This is because the CO 2 gas concentration increases due to the reduction reaction of the sintered ore 8 toward the upper part of the layer, so that the reaction of the formula (1) by the ferro-coke 7 is accelerated.
したがって、本発明においては、この効果を生かすために、高炉内においてＣＯ２ガス濃度の高い鉱石層上部且つ高炉炉壁近傍にフェロコークス７を配置することが好ましい。 Therefore, in the present invention, in order to take advantage of this effect, it is preferable to dispose the ferro-coke 7 above the ore layer having a high CO 2 gas concentration in the blast furnace and near the blast furnace wall.
使用する鉱石原料としては、図１に示す鉄鉱石の焼結鉱８に限らず、塊鉱石やペレットでも同様の効果が得られる。また、炭材内装鉱６を混合する鉱石層４及びフェロコークス７を混合する鉱石層５に、小塊コークスが混合されていても、同様の効果が得られる。 The ore raw material to be used is not limited to the iron ore sintered ore 8 shown in FIG. The same effect can be obtained even if the small coke is mixed in the ore layer 4 for mixing the carbonaceous material ore 6 and the ore layer 5 for mixing the ferro-coke 7.
また、炭材内装鉱６としては、微粉状の炭材と鉄鉱石とを混合して熱間成形したものや、冷間成型したもの、或いは、炭材核の周囲に鉄鉱石粉を被覆させて造粒し、焼結機で焼成したものであっても同様の効果が得られる。 The carbonaceous material ore 6 is obtained by mixing fine powdered carbonaceous material and iron ore and hot-forming or cold-forming them, or by coating iron ore powder around a carbon material core. The same effect can be obtained even if the material is granulated and fired by a sintering machine.
フェロコークス７及び炭材内装鉱６の使用量が少量のときには、双方の周囲に十分な鉄鉱石が存在するので、相互干渉が起こりにくく、本発明の効果は小さくなる。この観点から、フェロコークス７と炭材内装鉱６との合計使用量が、鉱石層全体に対して５体積％以上となる場合に、本発明を適用することが望ましい。 When the amounts of the ferrocoke 7 and the carbonaceous material ore 6 used are small, there is sufficient iron ore around both, so that mutual interference hardly occurs and the effect of the present invention is reduced. From this viewpoint, it is desirable to apply the present invention when the total usage of the ferrocoke 7 and the carbonaceous material ore 6 is 5% by volume or more based on the entire ore layer.
以上説明したように、本発明によれば、高炉において炭材内装鉱６とフェロコークス７とを併用する際に、炭材内装鉱６とフェロコークス７とを分離して鉱石層に装入するので、双方の効果が干渉することが防止され、従来よりも大幅に還元材比を低減することが可能になる。 As described above, according to the present invention, when the carbonaceous material ore 6 and the ferrocoke 7 are used together in the blast furnace, the carbonaceous material ore 6 and the ferrocoke 7 are separated and charged into the ore layer. Therefore, both effects are prevented from interfering with each other, and the ratio of the reducing material can be significantly reduced as compared with the related art.
本発明の効果を確認するために、炉容積５０００ｍ３の高炉で操業試験を行った。使用したフェロコークスは、石炭と鉄鉱石とを、乾留後のフェロコークスにおけるコークス分が７０質量％、金属鉄分が約３０質量％となるように配合して成型し、その後、竪型の乾留炉で乾留して製造したものである。また、使用した炭材内装鉱は、粒径３〜５ｍｍの粉コークスを核として、その周囲に鉄鉱石粉を被覆して擬似粒子を造粒し、この擬似粒子を焼結機で焼成したものである。鉱石原料は、鉄鉱石の焼結鉱を使用した。 In order to confirm the effect of the present invention, an operation test was performed in a blast furnace having a furnace volume of 5000 m 3 . The ferro-coke used was formed by blending and molding coal and iron ore such that the coke content in the ferro-coke after dry distillation was 70% by mass and the metallic iron content was approximately 30% by mass. It was manufactured by carbonization. Moreover, the carbonaceous material ore used is obtained by granulating pseudo-particles by coating iron ore powder around the core of fine coke having a particle size of 3 to 5 mm, and firing the pseudo-particles by a sintering machine. is there. As the ore raw material, a sintered ore of iron ore was used.
試験１では、フェロコークスの使用量を３０ｋｇ／溶銑−ｔ、炭材内装鉱の使用量を５５ｋｇ／溶銑−ｔとし、鉱石層を形成する鉱石原料の装入を２バッチとした。そして、フェロコークス及び炭材内装鉱の炉内配置場所及び２バッチの鉱石原料堆積層の頂点位置を変更し、そのときの還元材比を評価した。 In Test 1, the use amount of ferrocoke was 30 kg / hot metal-t, the use amount of the carbon material ore was 55 kg / hot metal-t, and the charging of the ore raw material forming the ore layer was performed in two batches. Then, the location of the ferrocoke and the carbonaceous material-containing ore in the furnace and the top positions of the two batches of the ore raw material deposition layer were changed, and the reducing material ratio at that time was evaluated.
いずれの試験も、出銑比を２．０溶銑−ｔ／ｍ３／ｄの一定とし、溶銑温度が１５００℃の一定となるように還元材比を調整した。１バッチ目及び２バッチ目の鉱石量の分配比は、２：１で一定とした。 In each test, the tapping ratio was constant at 2.0 hot metal-t / m 3 / d, and the reducing agent ratio was adjusted so that the hot metal temperature was constant at 1500 ° C. The distribution ratio of the ore amounts of the first batch and the second batch was kept constant at 2: 1.
表１に、各試験における試験条件と還元材比の調査結果を示す。ここで、堆積層の頂点位置として、炉中心を０、高炉炉壁を１．０とした無次元半径を使用した。 Table 1 shows the test conditions and the results of the investigation of the reducing material ratio in each test. Here, as a vertex position of the deposition layer, a dimensionless radius was used, where the furnace center was 0 and the blast furnace wall was 1.0.
比較例１は、フェロコークス及び炭材内装鉱を、それぞれ１バッチ目及び２バッチ目に、鉱石量の分配比なりに分配して操業した結果である。鉱石原料堆積層の頂点位置は、１バッチ目が０．７５の位置、２バッチ目が０．５５の位置となるように装入物分布を形成した。還元材比は５０９ｋｇ／溶銑−ｔであった。 Comparative Example 1 is a result of operating the ferrocoke and the carbonaceous material-containing ore in the first batch and the second batch, respectively, at a distribution ratio of the ore amount. The charge distribution was formed such that the top position of the ore raw material deposition layer was at a position of 0.75 in the first batch and at a position of 0.55 in the second batch. The reducing material ratio was 509 kg / hot metal-t.
比較例２は、比較例１と同等の原料条件で、堆積層頂点位置を１バッチ目が０．５５の位置、２バッチ目が０．７５の位置となるように変更した結果である。還元材比は、比較例１と同様に５０９ｋｇ／溶銑−ｔであった。 Comparative Example 2 is the result of changing the top position of the deposited layer to the position of 0.55 in the first batch and the position of 0.75 in the second batch under the same raw material conditions as in Comparative Example 1. The reducing agent ratio was 509 kg / hot metal-t as in Comparative Example 1.
比較例１及び比較例２の結果から、フェロコークス及び炭材内装鉱の混合状態が同じであれば、堆積層の頂点位置は還元材比に影響しないことがわかった。 From the results of Comparative Example 1 and Comparative Example 2, it was found that the apex position of the sedimentary layer did not affect the reducing material ratio when the mixed state of the ferrocoke and the carbonaceous material ore was the same.
本発明例１は、堆積層の頂点位置を比較例１と同じ位置とし、１バッチ目にフェロコークス、２バッチ目に炭材内装鉱を装入して操業した結果である。フェロコークスと炭材内装鉱とを分離したことで、還元材比は５０２ｋｇ／溶銑−ｔまで低減した。 Example 1 of the present invention is a result of operating with the apex position of the sedimentary layer being the same as that of Comparative Example 1 and charging ferrocoke in the first batch and charging the carbonaceous material ore in the second batch. By separating the ferrocoke and the carbonaceous material ore, the reducing material ratio was reduced to 502 kg / hot metal-t.
本発明例２は、堆積層の頂点位置を比較例１と同じ位置とし、１バッチ目に炭材内装鉱、２バッチ目にフェロコークスを装入して操業した結果である。本発明例１と比べて、フェロコークスがＣＯ２ガス濃度の高い上層に配置されたことで、還元材比は４９９ｋｇ／溶銑−ｔまで低下した。 Example 2 of the present invention is a result of operating with the top position of the sedimentary layer being the same as that of Comparative Example 1 and charging with carbonaceous material-containing ore in the first batch and ferro-coke in the second batch. Compared with Example 1 of the present invention, since the ferrocoke was disposed in the upper layer having a high CO 2 gas concentration, the reducing agent ratio was reduced to 499 kg / hot metal-t.
本発明例３は、堆積層の頂点位置を比較例２と同じ位置とし、１バッチ目に炭材内装鉱、２バッチ目にフェロコークスを装入して操業した結果である。本発明例２と比べて、２バッチ目の頂点位置を高炉炉壁側にずらしたことで、フェロコークスがよりＣＯ２ガス濃度の高い場所へ配置され、還元材比は４９７ｋｇ／溶銑−ｔまで低下した。 Example 3 of the present invention is a result of operating with the top position of the sedimentary layer being the same as that of Comparative Example 2 and charging the carbonaceous material-containing ore in the first batch and ferro-coke in the second batch. Compared with Example 2 of the present invention, by shifting the apex position of the second batch to the blast furnace wall side, ferro-coke is disposed in a place where the CO 2 gas concentration is higher, and the reducing agent ratio is up to 497 kg / hot metal-t. Dropped.
図９に、各試験における還元材比を比較して示す。図９に示すように、本発明の有効性が確認できた。 FIG. 9 shows a comparison of the reducing agent ratio in each test. As shown in FIG. 9, the effectiveness of the present invention was confirmed.
試験２では、鉱石層を形成する鉱石原料の装入を３バッチとし、フェロコークスの使用量を３０ｋｇ／溶銑−ｔ、炭材内装鉱の使用量を５５ｋｇ／溶銑−ｔとした。全てのケースにおいて各バッチの鉱石量の分配比は、１：１：１とし、１、２、３バッチ目の堆積層の頂点位置は、無次元半径でそれぞれ０．４０、０．６０、０．７５となるように装入物分布を形成した。その他の条件は試験１と同様とした。 In Test 2, the ore raw materials forming the ore layer were charged in three batches, the amount of ferrocoke used was 30 kg / hot metal-t, and the amount of carbonaceous material ore used was 55 kg / hot metal-t. In all cases, the distribution ratio of the amount of ore in each batch was set to 1: 1: 1, and the vertex positions of the first, second, and third batches were 0.40, 0.60, and 0, respectively, in a dimensionless radius. The charge distribution was formed to be .75. Other conditions were the same as in Test 1.
表２に、各試験における試験条件と還元材比の調査結果を示す。 Table 2 shows the test conditions and the results of the investigation of the reducing material ratio in each test.
比較例３は、フェロコークス及び炭材内装鉱を、各バッチに均等に分配して操業した結果である。還元材比は５１１ｋｇ／溶銑−ｔであった。 Comparative Example 3 is a result of operating the ferro-coke and the carbonaceous material-containing ore by equally distributing them to each batch. The reducing material ratio was 511 kg / hot metal-t.
本発明例４は、１バッチ目に焼結鉱のみを装入し、２バッチ目に炭材内装鉱を装入し、３バッチ目にフェロコークスを装入して操業した結果である。フェロコークスと炭材内装鉱とを分離したことで、還元材比は５０３ｋｇ／溶銑−ｔまで低減した。 Example 4 of the present invention is a result of charging only the sintered ore in the first batch, charging the carbonaceous material-containing ore in the second batch, and charging and ferro-coke in the third batch. The separation of the ferrocoke and the carbonaceous material ore reduced the reducing agent ratio to 503 kg / hot metal-t.
本発明例５は、１バッチ目及び３バッチ目に炭材内装鉱を装入し、２バッチ目にフェロコークスを装入して操業した結果である。還元材比は、５０２ｋｇ／溶銑−ｔまで低減した。 Inventive Example 5 is a result of charging and operating the carbonaceous material-containing ore in the first and third batches and charging ferrocoke in the second batch. The reducing agent ratio was reduced to 502 kg / hot metal-t.
１ 高炉中心線
２ 高炉炉壁
３ コークス層
４ 炭材内装鉱を混合する鉱石層
５ フェロコークスを混合する鉱石層
６ 炭材内装鉱
７ フェロコークス
８ 焼結鉱
９ 焼結鉱とフェロコークスと炭材内装鉱との混合充填層
１０ 焼結鉱と炭材内装鉱との混合充填層
１１ 焼結鉱とフェロコークスとの混合充填層
１２ 焼結鉱のみからなる鉱石層
１３ 黒鉛製容器
Reference Signs List 1 blast furnace center line 2 blast furnace wall 3 coke layer 4 ore layer mixing carbonaceous material ore 5 ore layer mixing ferrocoke 6 carbonaceous material ore 7 ferrocoke 8 sinter 9 sinter ore, ferrocoke and coal Mixed filling layer with material ore 10 Mixed filling layer with sintered ore and carbon material ore 11 Mixed filling layer with sinter and ferro-coke 12 Ore layer consisting only of sinter 13 Graphite vessel
Claims (3)
前記鉱石層の一部に炭材内装鉱を混合して装入し、且つ、前記鉱石層の他の一部にフェロコークスを混合して装入することとし、
前記鉱石層を少なくとも２バッチに分けて装入し、少なくとも一つのバッチで炭材内装鉱を混合した鉱石原料を装入し、少なくとも他の一つのバッチでフェロコークスを混合した鉱石原料を装入する、高炉の操業方法。 A method of operating a blast furnace in which a coke layer and an ore layer are alternately formed in a blast furnace,
Mixing and charging a carbonaceous material ore into a part of the ore layer, and mixing and charging ferro-coke into another part of the ore layer,
The ore layer is charged in at least two batches, at least one batch is charged with an ore raw material mixed with a carbonaceous material ore, and at least another batch is charged with an ore raw material mixed with ferro-coke. How to operate the blast furnace.
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