WO2024057693A1 - Method for producing iron ore pellet - Google Patents

Method for producing iron ore pellet Download PDF

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WO2024057693A1
WO2024057693A1 PCT/JP2023/025629 JP2023025629W WO2024057693A1 WO 2024057693 A1 WO2024057693 A1 WO 2024057693A1 JP 2023025629 W JP2023025629 W JP 2023025629W WO 2024057693 A1 WO2024057693 A1 WO 2024057693A1
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ore
iron ore
core
pellets
mass
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PCT/JP2023/025629
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French (fr)
Japanese (ja)
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健太 竹原
隆英 樋口
直人 中村
謙弥 堀田
頌平 藤原
友司 岩見
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Ｊｆｅスチール株式会社
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/242—Binding; Briquetting ; Granulating with binders

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  • the present invention relates to a method for producing iron ore pellets.
  • Iron ore pellets are iron ore powder that has been granulated to have properties (e.g. size, strength, reducibility, etc.) suitable for feeding into a blast furnace or solid reduction furnace.
  • iron ore pellets are generally produced by a process of pulverizing iron ore raw material to obtain fine ore, and mixing the fine ore, a binder, and optional auxiliary raw materials to form a mixture. granulating the mixture to obtain green pellets; and firing the green pellets to obtain iron ore pellets.
  • green pellets the pellets as granulated and before firing are referred to as "green pellets.”
  • the present invention aims to provide a method for producing iron ore pellets that yields green pellets that have high strength and can suppress bursting.
  • the present inventors conducted extensive studies and found that in addition to iron ore with a particle size of 1 mm or less obtained by pulverizing iron ore raw materials, iron ore with a particle size of 1 mm or less obtained without pulverizing iron ore raw materials It has been found that by mixing and granulating iron ore with a certain particle size to produce green pellets, the falling strength of the green pellets can be ensured and bursting can be suppressed.
  • the gist of the present invention which was completed based on the above findings, is as follows.
  • the particle size and mass ratio of the core ore are set so that the number of core ores contained in each iron ore pellet is 0.9 to 1.0 on average, [1] to [6] ] The method for producing iron ore pellets according to any one of the above.
  • the mass of the fine ore is W1
  • the mass of the binder is W2
  • W2/W1 ⁇ 100 is 1.0 or more.
  • the iron ore pellet manufacturing method of the present invention makes it possible to obtain green pellets that are high in strength and suppress bursting.
  • FIG. 1 is a diagram schematically showing a cross section of an iron ore pellet obtained according to an embodiment of the present invention.
  • FIG. 2 is a diagram schematically showing a growth process in a green pellet granulation process in an embodiment of the present invention and a comparative example.
  • FIG. 2 is a diagram schematically showing the outline of an electric furnace used for bursting temperature measurement.
  • a method for producing iron ore pellets according to an embodiment of the present invention includes a step of mixing iron ore with a total Fe content of 63% by mass or less and a binder to obtain a mixture, and granulating the mixture to obtain green pellets. and a step of firing the green pellets to obtain iron ore pellets.
  • the iron ore for obtaining the mixture is characterized by having a core ore having a particle size of more than 1 mm and a fine ore having a particle size of 1 mm or less.
  • iron ore particles having a particle size of more than 1 mm, which are obtained without pulverizing the iron ore raw material are referred to as "core ore", and iron ore particles having a particle size of 1 mm or less, which are obtained by pulverizing the iron ore raw material.
  • the stone particles are called "fine ore”.
  • core ore is used in addition to fine ore as the iron ore that constitutes the green pellets. Since the green pellets contain high-strength core ore, the strength of the green pellets can be ensured. In addition, compared to the conventional technology in which the iron ore constituting the green pellets is only fine ore, in this embodiment, the green pellets include core ore with a large particle size, so it is possible to reduce the speed of drying and decrystallization water. can. By containing the core ore, the porosity of the green pellets is lowered, and the green pellets are dense, making it difficult to retain water. In addition, since there are few gas paths, it is difficult for steam to be generated from inside the green pellets. As a result, bursting can be sufficiently suppressed.
  • the "particle size" of iron ore corresponds to the nominal opening of a sieve screen in accordance with JIS Z 8801:2019. That is, iron ore having a particle size exceeding X mm is iron ore that remains on the sieve when it is sieved through a sieve with a nominal opening of X mm. Iron ore having a particle size of Ymm or less is iron ore that passes through the sieve and becomes the bottom of the sieve when it is sieved through a sieve with a nominal opening of Ymm.
  • the type and characteristics of the core ore are not particularly limited as long as it is iron ore with a particle size exceeding 1 mm and a total Fe content of 63% by mass or less. Moreover, it is preferable that the particle size of the core ore is 9.5 mm or less. When the particle size is 9.5 mm or less, the size of the completed iron ore pellets is suitable, and the subsequent reduction treatment etc. can be performed uniformly.
  • the mass ratio of the core ore is preferably 15% by mass or more based on the total iron ore. This means that the more core ore that has a larger volume than normal crushed iron ore powder, the more effective the binder such as bentonite can be even with a small amount, and the better the strength improvement and bursting suppressing effect can be obtained. It is from.
  • the mass ratio of particles having a particle size of more than 2.8 mm in the core ore is 15% by mass or more based on the total iron ore. , more preferably 30% by mass or more.
  • the mass ratio of the core ore having a particle size of more than 1 mm and less than or equal to 2.8 mm is not particularly limited and may be 0 mass %.
  • the mass ratio of particles having a particle size of more than 4.8 mm in the core ore is 10% by mass or more with respect to the total iron ore, More preferably, the content is 25% by mass or more.
  • the mass ratio of the core ore having a particle size of more than 1 mm and less than 4.8 mm is not particularly limited and may be 0 mass %.
  • the mass ratio of the core ore is preferably 99% by mass or less, more preferably 75% by mass or less based on the total iron ore.
  • the mass ratio of particles having a particle size of more than 1 mm is at most about 75% by mass.
  • Powdered ore is obtained by crushing iron ore using a general ball mill or the like.
  • the average particle size of the fine ore is preferably about several tens of micrometers.
  • the Blaine index of the fine ore is preferably about 2000 to 4000 cm 2 /g, more preferably about 2500 to 3500 cm 2 /g. When the Blaine index is 2000 cm 2 /g or more, the efficiency of powder production is more suitable. When the Blaine index is 4000 cm 2 /g or less, shrinkage due to sintering during firing is suppressed, and the strength is more suitable.
  • the Blaine index is measured using a Blaine air permeation device specified in JIS R 5201:2015, and represents the specific surface area of the powder. In the pellet manufacturing process, the Blaine index is used as a control index for ore particle size, and the higher the value, the more fine the ore is.
  • the iron ore raw material is sieved through a sieve with 1 mm openings, the top of the sieve is used as core ore, and the bottom of the sieve is crushed and used as fine ore. is preferable.
  • each may be prepared separately from iron ore raw materials.
  • each of the iron ore pellets obtained in this embodiment preferably contains one core ore 10, with fine ore 12 attached to the surface of the core ore 10. It is preferable that the same applies to the green pellet stage. When the green pellets and iron ore pellets contain one core ore, strength can be suitably obtained.
  • FIG. 2 shows a schematic diagram (cross-sectional view) of the growth process in the granulation process of green pellets.
  • layering granulation occurs in which fine ore 12, binder, etc. adhere to the surface of core ore 10 in a layered manner. It will be done.
  • the green pellets do not contain core ore, it is thought that a core 14 of powder aggregates is formed by fine ore instead of core ore, and the core 14 of the powder aggregate is covered with fine ore and granulation progresses, but the binder is inside the green pellet.
  • the strength decreases because the particles are dispersed into
  • the green pellet contains more than one core ore, it is necessary to wrap the fine ore layer around multiple core ores at once during the growth process, and the particles grow rapidly, resulting in a dense covering layer. The strength will be lower than when there is only one core ore.
  • the particle size and mass ratio of the core ore so that the number of core ores contained in one iron ore pellet is on average 0.9 to 1.0.
  • the weight ratio G of the core ore can be determined from the sizes of the core ore and green pellets as follows.
  • the weight ratio G of the core ore in the green pellet is considered to be equal to the effective volume ratio of the core ore in the green pellet (the volume ratio excluding the pores in the aggregate of fine ore).
  • “(1-T)*(1-K)” is the volume ratio of the fine ore aggregate in the green pellet excluding the pore portion.
  • bentonite is preferred, but any known or arbitrary binder, such as organic or inorganic binders that provide similar effects, may be used.
  • limestone, dolomite, or the like may be mixed as an auxiliary raw material.
  • auxiliary raw materials various reducing agents, additives, etc. may be added depending on the type of furnace used for the reduction treatment after firing. Specifically, a carbon material such as coal or coke may be used as the reducing agent.
  • the amount of binder in the mixture is as follows: W1 is the mass of fine ore, W2 is the mass of binder, W2/W1 ⁇ 100 ⁇ 1.0 It is preferable that the amount satisfies the following. Within the above range, the amount of binder is suitable for the fine ore, the effect of the binder can be suitably obtained, and the strength can be ensured. The above range is more preferably 1.4 or more, and even more preferably 1.6 or more. The larger the amount of binder, the easier it is to ensure pellet strength, but since the purity of reduced iron decreases, it is preferably in the range of 3.0 or less.
  • Iron ore pellets are manufactured by common crushing, mixing, granulation, and calcination processes.
  • the pulverization process may be performed using a pulverizer such as a general ball mill, and is performed only on iron ore used as fine ore.
  • a common concrete mixer or the like may be used in the mixing step.
  • a general pelletizer, drum mixer, etc. may be used for the granulation process.
  • a general shaft furnace, rotary kiln, or the like may be used.
  • the granulated green pellets preferably have a size of about 9.5 to 12 mm. If the size of the green pellets is less than 9.5 mm, air permeability will deteriorate when the green pellets are filled into a blast furnace as fired pellets. If the size of the green pellet exceeds 12 mm, the reducibility will decrease.
  • the iron ore After drying the iron ore at 105°C for 24 hours, it was sieved using a sieve with openings of 1.0 mm, 2.8 mm, 4.8 mm, 6.7 mm, 8.0 mm, and 9.5 mm using a low tap. The iron ore on these sieves was used as core ore. Table 1 shows the components of the iron ore used as a raw material. In addition, T. Fe is the total amount of iron in the iron ore, and LOI (Loss on Ignition) is the loss on ignition during measurement. Iron ore having the same composition as above was similarly dried at 105° C. for 24 hours and then ground in a ball mill to obtain iron ore powder. The entire amount of fine ore passes through a sieve with an opening of 1.0 mm, that is, it has a particle size of 1 mm or less. The Blaine index of the fine ore was 2560 cm 2 /g.
  • core ore and fine ore were prepared so that the total amount was 5000 g, and mixed with bentonite at a predetermined ratio for 3 minutes at 20 rpm using a concrete mixer.
  • the amount of bentonite added (mass %) to the entire iron ore (total of core ore and fine ore) is shown in the "bentonite ratio" column of Table 2.
  • the mixed raw materials were placed in a 1.2 m ⁇ pelletizer and granulated while adding water. Pellet particles of 9.5 to 12 mm were collected and rolled in a pelletizer for an additional 10 minutes to obtain green pellets.
  • the blending amounts of the core ore and fine ore were adjusted so that the number of core ores contained in one green pellet was 1.0 on average.
  • Table 2 shows the volume ratio of core ore to green pellets and the number of core ores per green pellet. Note that the porosity was 33%.
  • FIG. 3 schematically shows the outline of the electric furnace used in this example.
  • a green pellet filling basket 32 filled with 200 g of green pellets is placed in an electric furnace 30, and hot air (air) at 200°C (measured with a thermocouple 34) is flowed from a heating gas source 36 at a flow rate of 1.2 m/sec. , and held for 10 minutes. After holding, the sample was taken out and checked for rupture. If no rupture was confirmed, the temperature of the hot air was increased in increments of 40°C, a new sample was placed in the furnace, and the same test was repeated. The temperature at which bursting of the sample was confirmed was defined as the bursting temperature, and the results are shown in Table 2.

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Abstract

Provided is a method for producing an iron ore pellet, whereby it is possible to obtain a high-strength green pellet in which bursting can be suppressed. This method for producing an iron ore pellet is characterized by having a step for mixing a binder and iron ore having a total Fe content of 63% by mass to obtain a mixture, a step for granulating the mixture to obtain a green pellet, and a step for firing the green pellet to obtain an iron ore pellet, the iron ore having a core ore 10 having a grain size of more than 1 mm, and a fine ore 12 having a grain size of 1 mm or less.

Description

鉄鉱石ペレットの製造方法Method for manufacturing iron ore pellets
　本発明は、鉄鉱石ペレットの製造方法に関する。 The present invention relates to a method for producing iron ore pellets.
　鉄鉱石ペレットとは、鉄鉱石粉を高炉や固体還元炉に投入するのに適した性状（例えばサイズ、強度、被還元性など）に造粒加工したものである。例えば特許文献１に記載されているように、鉄鉱石ペレットは、一般に、鉄鉱石原料を粉砕して粉鉱石を得る工程と、該粉鉱石とバインダーと任意の副原料とを混合して混合物を得る工程と、該混合物を造粒してグリーンペレットを得る工程と、該グリーンペレットを焼成して鉄鉱石ペレットを得る工程と、によって製造される。本明細書において、造粒まま焼成前のペレットを「グリーンペレット」と称する。 Iron ore pellets are iron ore powder that has been granulated to have properties (e.g. size, strength, reducibility, etc.) suitable for feeding into a blast furnace or solid reduction furnace. For example, as described in Patent Document 1, iron ore pellets are generally produced by a process of pulverizing iron ore raw material to obtain fine ore, and mixing the fine ore, a binder, and optional auxiliary raw materials to form a mixture. granulating the mixture to obtain green pellets; and firing the green pellets to obtain iron ore pellets. In this specification, the pellets as granulated and before firing are referred to as "green pellets."
　鉄鉱石ペレットの製造において、グリーンペレットの強度を確保することは、焼成炉へ入れる前のハンドリング中にグリーンペレットが粉化して、焼成炉内に粉体が付着することを抑制するために重要である。また、グリーンペレットのバースティングを抑制することも、焼成後の鉄鉱石ペレットの強度確保のために重要である。バースティングとは、グリーンペレットが乾燥・脱結晶水する際に内部から発生する蒸気の圧力によりグリーンペレットが破裂する現象である。バースティングが生じるとグリーンペレットに亀裂が生じてしまうため、焼成後の鉄鉱石ペレットの強度が著しく低下する。特に、グリーンペレットの強度を確保するために、粉砕した粉鉱石の粒径を小さくすると、グリーンペレットが高密度化して、バースティングが生じやすい。すなわち、グリーンペレットの強度確保とバースティングの抑制とは両立が困難な課題であった。 In the production of iron ore pellets, it is important to ensure the strength of the green pellets in order to prevent the green pellets from pulverizing during handling before being put into the kiln and from adhering to the inside of the kiln. be. In addition, it is also important to suppress bursting of green pellets in order to ensure the strength of iron ore pellets after firing. Bursting is a phenomenon in which green pellets burst due to the pressure of steam generated from inside when the green pellets are dried and decrystallized. When bursting occurs, cracks occur in the green pellets, which significantly reduces the strength of the iron ore pellets after firing. In particular, if the particle size of the crushed ore powder is reduced in order to ensure the strength of the green pellets, the green pellets become denser and bursting tends to occur. In other words, it has been difficult to simultaneously ensure the strength of green pellets and suppress bursting.
特開２０２２－３４２１０号公報JP2022-34210A
　グリーンペレットの強度を確保することを目的として、又は、グリーンペレットのバースティングを抑制することを目的として、バインダーとしてベントナイトを添加したり、種々の有機・無機バインダーを添加することも行われている。しかし、グリーンペレットの強度を確保し、かつバースティングを抑制する観点からは、改善の余地があった。 In order to ensure the strength of green pellets or to suppress bursting of green pellets, bentonite is added as a binder, and various organic and inorganic binders are also added. . However, there was room for improvement from the viewpoint of ensuring the strength of the green pellets and suppressing bursting.
　そこで本発明は、上記課題に鑑み、高強度であり、かつバースティングを抑制できるグリーンペレットが得られる鉄鉱石ペレットの製造方法を提供することを目的とする。 In view of the above problems, the present invention aims to provide a method for producing iron ore pellets that yields green pellets that have high strength and can suppress bursting.
　この目的を達成すべく本発明者らが鋭意検討したところ、鉄鉱石原料を粉砕して得られる１ｍｍ以下の粒度を有する鉄鉱石に加えて、鉄鉱石原料を粉砕することなく得られる１ｍｍ超えの粒度を有する鉄鉱石を用い、これらを混合、造粒してグリーンペレットを作製することで、グリーンペレットの落下強度が確保でき、かつバースティングを抑制できるとの知見を得た。 In order to achieve this objective, the present inventors conducted extensive studies and found that in addition to iron ore with a particle size of 1 mm or less obtained by pulverizing iron ore raw materials, iron ore with a particle size of 1 mm or less obtained without pulverizing iron ore raw materials It has been found that by mixing and granulating iron ore with a certain particle size to produce green pellets, the falling strength of the green pellets can be ensured and bursting can be suppressed.
　上記知見に基づき完成された本発明の要旨構成は、以下のとおりである。 The gist of the present invention, which was completed based on the above findings, is as follows.
　［１］全Ｆｅ量６３質量％以下の鉄鉱石とバインダーとを混合して、混合物を得る工程と、
　前記混合物を造粒して、グリーンペレットを得る工程と、
　前記グリーンペレットを焼成して、鉄鉱石ペレットを得る工程と、
を有し、
　前記鉄鉱石は、１ｍｍ超えの粒度を有する核鉱石と、１ｍｍ以下の粒度を有する粉鉱石と、を有することを特徴とする、鉄鉱石ペレットの製造方法。 [1] A step of mixing iron ore with a total Fe content of 63% by mass or less and a binder to obtain a mixture;
granulating the mixture to obtain green pellets;
Calculating the green pellets to obtain iron ore pellets;
has
A method for producing iron ore pellets, wherein the iron ore includes a core ore having a particle size of more than 1 mm and a fine ore having a particle size of 1 mm or less.
　［２］前記核鉱石の質量比率が、前記鉄鉱石に対して１５質量％以上である、［１］に記載の鉄鉱石ペレットの製造方法。 [2] The method for producing iron ore pellets according to [1], wherein a mass ratio of the core ore to the iron ore is 15% by mass or more.
　［３］前記核鉱石のうち、２．８ｍｍ超えの粒度を有する粒子の質量比率が、前記鉄鉱石に対して１５質量％以上である、［２］に記載の鉄鉱石ペレットの製造方法。 [3] The method for producing iron ore pellets according to [2], wherein the mass ratio of particles having a particle size of more than 2.8 mm in the core ore is 15% by mass or more based on the iron ore.
　［４］前記核鉱石のうち、２．８ｍｍ超えの粒度を有する粒子の質量比率が、前記鉄鉱石に対して３０質量％以上である、［２］に記載の鉄鉱石ペレットの製造方法。 [4] The method for producing iron ore pellets according to [2], wherein the mass ratio of particles having a particle size of more than 2.8 mm in the core ore is 30% by mass or more based on the iron ore.
　［５］前記核鉱石のうち、４．８ｍｍ超えの粒度を有する粒子の質量比率が、前記鉄鉱石に対して１０質量％以上である、［１］に記載の鉄鉱石ペレットの製造方法。 [5] The method for producing iron ore pellets according to [1], wherein the mass ratio of particles having a particle size of more than 4.8 mm in the core ore is 10% by mass or more based on the iron ore.
　［６］前記核鉱石のうち、４．８ｍｍ超えの粒度を有する粒子の質量比率が、前記鉄鉱石に対して２５質量％以上である、［５］に記載の鉄鉱石ペレットの製造方法。 [6] The method for producing iron ore pellets according to [5], wherein the mass ratio of particles having a particle size exceeding 4.8 mm in the core ore is 25% by mass or more based on the iron ore.
　［７］前記鉄鉱石ペレット１つ当たりに含まれる前記核鉱石の個数が平均０．９～１．０となるように、前記核鉱石の粒度及び質量比率を設定する、［１］～［６］のいずれか一項に記載の鉄鉱石ペレットの製造方法。 [7] The particle size and mass ratio of the core ore are set so that the number of core ores contained in each iron ore pellet is 0.9 to 1.0 on average, [1] to [6] ] The method for producing iron ore pellets according to any one of the above.
　［８］鉄鉱石原料を１ｍｍの目開きを有する篩で篩い分けし、篩上を前記核鉱石として用い、篩下を粉砕して前記粉鉱石として用いる、［１］～［７］のいずれか一項に記載の鉄鉱石ペレットの製造方法。 [8] Any one of [1] to [7], wherein the iron ore raw material is sieved through a sieve with an opening of 1 mm, the upper part of the sieve is used as the core ore, and the lower part is crushed and used as the powder ore. The method for producing iron ore pellets according to item 1.
　［９］前記混合物において、前記粉鉱石の質量をＷ１とし、前記バインダーの質量をＷ２として、Ｗ２／Ｗ１×１００を１．０以上とする、［１］～［８］のいずれか一項に記載の鉄鉱石ペレットの製造方法。 [9] In any one of [1] to [8], in the mixture, the mass of the fine ore is W1, the mass of the binder is W2, and W2/W1×100 is 1.0 or more. A method for producing iron ore pellets as described.
　［１０］前記バインダーがベントナイトである、［１］～［９］のいずれか一項に記載の鉄鉱石ペレットの製造方法。 [10] The method for producing iron ore pellets according to any one of [1] to [9], wherein the binder is bentonite.
　本発明の鉄鉱石ペレットの製造方法によれば、高強度であり、かつバースティングを抑制できるグリーンペレットを得ることができる。 The iron ore pellet manufacturing method of the present invention makes it possible to obtain green pellets that are high in strength and suppress bursting.
本発明の実施形態により得られる鉄鉱石ペレットの断面を模式的に示した図である。1 is a diagram schematically showing a cross section of an iron ore pellet obtained according to an embodiment of the present invention. 本発明の実施形態及び比較例において、グリーンペレットの造粒工程における成長過程を模式的に示した図である。FIG. 2 is a diagram schematically showing a growth process in a green pellet granulation process in an embodiment of the present invention and a comparative example. バースティング温度測定に使用した電気炉の概略を模式的に示した図である。FIG. 2 is a diagram schematically showing the outline of an electric furnace used for bursting temperature measurement.
　以下、本発明に係る鉄鉱石ペレットの製造方法の実施形態を説明する。なお、以下に説明する実施形態は、本発明を具体化した一例であって、その具体例をもって本発明の構成を限定するものではない。 Hereinafter, embodiments of the method for producing iron ore pellets according to the present invention will be described. Note that the embodiment described below is an example of embodying the present invention, and the configuration of the present invention is not limited to the specific example.
　本発明の一実施形態による鉄鉱石ペレットの製造方法は、全Ｆｅ量６３質量％以下の鉄鉱石とバインダーとを混合して、混合物を得る工程と、前記混合物を造粒して、グリーンペレットを得る工程と、前記グリーンペレットを焼成して、鉄鉱石ペレットを得る工程と、を有する。そして、混合物を得るための鉄鉱石は、１ｍｍ超えの粒度を有する核鉱石と、１ｍｍ以下の粒度を有する粉鉱石と、を有することが特徴である。 A method for producing iron ore pellets according to an embodiment of the present invention includes a step of mixing iron ore with a total Fe content of 63% by mass or less and a binder to obtain a mixture, and granulating the mixture to obtain green pellets. and a step of firing the green pellets to obtain iron ore pellets. The iron ore for obtaining the mixture is characterized by having a core ore having a particle size of more than 1 mm and a fine ore having a particle size of 1 mm or less.
　本明細書において、鉄鉱石原料を粉砕することなく得られる、１ｍｍ超えの粒度を有する鉄鉱石粒子を「核鉱石」と称し、鉄鉱石原料を粉砕して得られる、１ｍｍ以下の粒度を有する鉄鉱石粒子を「粉鉱石」を称する。 In this specification, iron ore particles having a particle size of more than 1 mm, which are obtained without pulverizing the iron ore raw material, are referred to as "core ore", and iron ore particles having a particle size of 1 mm or less, which are obtained by pulverizing the iron ore raw material. The stone particles are called "fine ore".
　本実施形態では、グリーンペレットを構成する鉄鉱石として、粉鉱石に加えて核鉱石を用いる。グリーンペレットが高強度な核鉱石を含むことで、グリーンペレットの強度を確保することができる。また、グリーンペレットを構成する鉄鉱石が粉鉱石のみからなる従来技術に比べて、本実施形態では、グリーンペレットが粒度の大きい核鉱石を含むため、乾燥・脱結晶水の速度を低下させることができる。核鉱石を含むことで、グリーンペレットの空隙率が低くなり、密であるため水分を担持しにくい。また、ガスパスが少ないため、グリーンペレットの内部から蒸気が発生しにくい。その結果、バースティングを十分に抑制することができる。 In this embodiment, core ore is used in addition to fine ore as the iron ore that constitutes the green pellets. Since the green pellets contain high-strength core ore, the strength of the green pellets can be ensured. In addition, compared to the conventional technology in which the iron ore constituting the green pellets is only fine ore, in this embodiment, the green pellets include core ore with a large particle size, so it is possible to reduce the speed of drying and decrystallization water. can. By containing the core ore, the porosity of the green pellets is lowered, and the green pellets are dense, making it difficult to retain water. In addition, since there are few gas paths, it is difficult for steam to be generated from inside the green pellets. As a result, bursting can be sufficiently suppressed.
　本発明において、鉄鉱石の「粒度」とは、ＪＩＳ　Ｚ　８８０１：２０１９に準拠した篩網の公称目開きに相当する。すなわち、Ｘｍｍ超えの粒度を有する鉄鉱石とは、公称目開きＸｍｍの篩で篩分けした際に篩上に残る鉄鉱石である。Ｙｍｍ以下の粒度を有する鉄鉱石とは、公称目開きＹｍｍの篩で篩分けした際に、篩を通過して篩下となる鉄鉱石である。 In the present invention, the "particle size" of iron ore corresponds to the nominal opening of a sieve screen in accordance with JIS Z 8801:2019. That is, iron ore having a particle size exceeding X mm is iron ore that remains on the sieve when it is sieved through a sieve with a nominal opening of X mm. Iron ore having a particle size of Ymm or less is iron ore that passes through the sieve and becomes the bottom of the sieve when it is sieved through a sieve with a nominal opening of Ymm.
　核鉱石は、１ｍｍ超えの粒度を有する全Ｆｅ量６３質量％以下の鉄鉱石であれば、その種類及び特性は特に限定されない。また、核鉱石は粒度が９．５ｍｍ以下であることが好ましい。粒度が９．５ｍｍ以下であると、完成した鉄鉱石ペレットの大きさが好適であり、後の還元処理などが均一に行える。 The type and characteristics of the core ore are not particularly limited as long as it is iron ore with a particle size exceeding 1 mm and a total Fe content of 63% by mass or less. Moreover, it is preferable that the particle size of the core ore is 9.5 mm or less. When the particle size is 9.5 mm or less, the size of the completed iron ore pellets is suitable, and the subsequent reduction treatment etc. can be performed uniformly.
　核鉱石の質量比率は、全鉄鉱石に対して１５質量％以上であることが好ましい。これは、通常の粉砕した鉄鉱石粉よりも体積が大きい核鉱石が多いほど、ベントナイト等のバインダーが少量であっても効果を発揮することができ、強度向上およびバースティング抑制効果が好適に得られるからである。 The mass ratio of the core ore is preferably 15% by mass or more based on the total iron ore. This means that the more core ore that has a larger volume than normal crushed iron ore powder, the more effective the binder such as bentonite can be even with a small amount, and the better the strength improvement and bursting suppressing effect can be obtained. It is from.
　同様に、本発明の効果をより十分に得る観点から、核鉱石のうち、２．８ｍｍ超えの粒度を有する粒子の質量比率が、全鉄鉱石に対して１５質量％以上であるのがより好ましく、３０質量％以上であるのがさらに好ましい。このとき、１ｍｍ超え２．８ｍｍ以下の粒度の核鉱石の質量比率は、特に制限はなく０質量％でも良い。 Similarly, from the viewpoint of obtaining the effects of the present invention more fully, it is more preferable that the mass ratio of particles having a particle size of more than 2.8 mm in the core ore is 15% by mass or more based on the total iron ore. , more preferably 30% by mass or more. At this time, the mass ratio of the core ore having a particle size of more than 1 mm and less than or equal to 2.8 mm is not particularly limited and may be 0 mass %.
　同様に、本発明の効果をより十分に得る観点から、核鉱石のうち、４．８ｍｍ超えの粒度を有する粒子の質量比率が、全鉄鉱石に対して１０質量％以上であるのが好ましく、２５質量％以上であるのがさらに好ましい。このとき、１ｍｍ超え４．８ｍｍ以下の粒度の核鉱石の質量比率は、特に制限はなく０質量％でも良い。 Similarly, from the viewpoint of obtaining the effects of the present invention more fully, it is preferable that the mass ratio of particles having a particle size of more than 4.8 mm in the core ore is 10% by mass or more with respect to the total iron ore, More preferably, the content is 25% by mass or more. At this time, the mass ratio of the core ore having a particle size of more than 1 mm and less than 4.8 mm is not particularly limited and may be 0 mass %.
　また、核鉱石の質量比率は、全鉄鉱石に対して９９質量％以下とするのが好ましく、７５質量％以下とするのがより好ましい。なお、一般的な鉄鉱石原料においては、１ｍｍ超えの粒度を有する粒子の質量比率は多くても７５質量％程度である。 Furthermore, the mass ratio of the core ore is preferably 99% by mass or less, more preferably 75% by mass or less based on the total iron ore. In addition, in a general iron ore raw material, the mass ratio of particles having a particle size of more than 1 mm is at most about 75% by mass.
　粉鉱石は、鉄鉱石を一般的なボールミルなどを使用して粉砕することで得られる。粉鉱石の平均粒径は数十μｍ程度であるのが好ましい。粉鉱石のブレーン指数は２０００～４０００ｃｍ２／ｇ程度であるのが好ましく、２５００～３５００ｃｍ２／ｇ程度であるのがより好ましい。ブレーン指数が２０００ｃｍ２／ｇ以上であると、造粉の効率がより好適である。ブレーン指数が４０００ｃｍ２／ｇ以下であると、焼成時の焼結に伴う収縮が抑制され、強度がより好適である。なお、ブレーン指数とはＪＩＳ　Ｒ　５２０１：２０１５に規定のブレーン空気透過装置で測定されるものであって、粉体の比表面積を表す。ペレット製造プロセスにおいて、ブレーン指数は鉱石粒度の管理指標として用いられており、この値が高いほどより微粉になっていることを意味する。 Powdered ore is obtained by crushing iron ore using a general ball mill or the like. The average particle size of the fine ore is preferably about several tens of micrometers. The Blaine index of the fine ore is preferably about 2000 to 4000 cm 2 /g, more preferably about 2500 to 3500 cm 2 /g. When the Blaine index is 2000 cm 2 /g or more, the efficiency of powder production is more suitable. When the Blaine index is 4000 cm 2 /g or less, shrinkage due to sintering during firing is suppressed, and the strength is more suitable. The Blaine index is measured using a Blaine air permeation device specified in JIS R 5201:2015, and represents the specific surface area of the powder. In the pellet manufacturing process, the Blaine index is used as a control index for ore particle size, and the higher the value, the more fine the ore is.
　核鉱石と粉鉱石の製造方法は、特に指定はないが、鉄鉱石原料を１ｍｍの目開きを有する篩で篩い分けし、篩上を核鉱石として用い、篩下を粉砕して粉鉱石として用いるのが好ましい。もしくは、それぞれを別途、鉄鉱石原料から用意しても良い。 There is no specific method for producing core ore and fine ore, but the iron ore raw material is sieved through a sieve with 1 mm openings, the top of the sieve is used as core ore, and the bottom of the sieve is crushed and used as fine ore. is preferable. Alternatively, each may be prepared separately from iron ore raw materials.
　図１に示すように、本実施形態において得られる鉄鉱石ペレットの各々は、核鉱石１０を１つ含み、核鉱石１０の表面に粉鉱石１２が付着してなるものであることが好ましい。グリーンペレットの段階でも同様であることが好ましい。グリーンペレット及び鉄鉱石ペレットが核鉱石を１つ含む場合、好適に強度を得ることができる。 As shown in FIG. 1, each of the iron ore pellets obtained in this embodiment preferably contains one core ore 10, with fine ore 12 attached to the surface of the core ore 10. It is preferable that the same applies to the green pellet stage. When the green pellets and iron ore pellets contain one core ore, strength can be suitably obtained.
　発明者らは、グリーンペレット及び鉄鉱石ペレットに含まれる核鉱石を１つにした場合、高い強度が得られる理由について以下のように考えている。図２にグリーンペレットの造粒工程における成長過程の模式図（断面図）を示す。本発明例のように、ペレット１つに含まれる核鉱石の個数を１つにした場合、核鉱石１０の表面に、粉鉱石１２およびバインダー等が層状に付着するレイヤーリング造粒が起こると考えられる。グリーンペレットが核鉱石を含まない場合、核鉱石の代わりに粉鉱石による粉凝集体の核１４が形成され、それを粉鉱石が被覆して造粒が進むと考えられるが、バインダーがグリーンペレット内に分散されるため、強度が低下してしまう。また、グリーンペレットに含まれる核鉱石が１個を超える場合、成長過程で一度に複数の核鉱石を粉鉱石の層が包み込む必要があり、粒子が急速に成長するため、被覆する層が緻密になる時間が不足して、核鉱石が１つの場合より強度が低くなる。 The inventors believe that the reason why high strength is obtained when the core ores contained in green pellets and iron ore pellets are combined is as follows. FIG. 2 shows a schematic diagram (cross-sectional view) of the growth process in the granulation process of green pellets. When the number of core ores contained in one pellet is reduced to one as in the example of the present invention, it is thought that layering granulation occurs in which fine ore 12, binder, etc. adhere to the surface of core ore 10 in a layered manner. It will be done. If the green pellets do not contain core ore, it is thought that a core 14 of powder aggregates is formed by fine ore instead of core ore, and the core 14 of the powder aggregate is covered with fine ore and granulation progresses, but the binder is inside the green pellet. The strength decreases because the particles are dispersed into In addition, if the green pellet contains more than one core ore, it is necessary to wrap the fine ore layer around multiple core ores at once during the growth process, and the particles grow rapidly, resulting in a dense covering layer. The strength will be lower than when there is only one core ore.
　そこで、本実施形態では、鉄鉱石ペレット１つ当たりに含まれる核鉱石の個数が平均０．９～１．０となるように、核鉱石の粒度及び質量比率を設定することが好ましい。核鉱石およびグリーンペレットのサイズから核鉱石の重量割合Ｇを次のように計算して求めることができる。核鉱石のグリーンペレットにおける重量割合Ｇは、核鉱石のグリーンペレットにおける有効体積割合（粉鉱石の凝集体における気孔部分を除いた体積比）に等しいと考えられる。グリーンペレットの体積（粉鉱石の凝集体部分の気孔も含めた、ペレットの「かさ体積」）に対する核鉱石の体積比をＴ、粉鉱石の凝集体における気孔率をＫとして、重量割合Ｇは下記式（１）のように表せる。
Ｇ＝Ｔ／｛（１－Ｔ）＊（１－Ｋ）＋Ｔ｝　・・・（１）
ここで、「（１－Ｔ）＊（１－Ｋ）」は、グリーンペレットにおける粉鉱石の凝集体の、気孔部分を除いた体積比である。式（１）を満たすように、核鉱石の重量割合や、核鉱石の粒度を調整することで、グリーンペレットに核鉱石が平均して１つ含まれるようにすることができる。なお、グリーンペレットの気孔率Ｋは、一般に粉鉱石の粉砕粒度によって定まり、例えば０．３３を採用することができる。 Therefore, in this embodiment, it is preferable to set the particle size and mass ratio of the core ore so that the number of core ores contained in one iron ore pellet is on average 0.9 to 1.0. The weight ratio G of the core ore can be determined from the sizes of the core ore and green pellets as follows. The weight ratio G of the core ore in the green pellet is considered to be equal to the effective volume ratio of the core ore in the green pellet (the volume ratio excluding the pores in the aggregate of fine ore). Assuming that the volume ratio of the core ore to the volume of the green pellet (the "bulk volume" of the pellet, including the pores in the fine ore aggregate) is T, and the porosity of the fine ore aggregate is K, the weight ratio G is as follows: It can be expressed as in equation (1).
G=T/{(1-T)*(1-K)+T} ...(1)
Here, "(1-T)*(1-K)" is the volume ratio of the fine ore aggregate in the green pellet excluding the pore portion. By adjusting the weight ratio of the core ore and the particle size of the core ore so as to satisfy formula (1), it is possible to make the green pellet contain one core ore on average. The porosity K of the green pellets is generally determined by the pulverized particle size of the fine ore, and may be set to 0.33, for example.
　造粒時に用いるバインダーとしては、ベントナイトが好ましいが、同様の効果が得られる有機・無機バインダー等、公知又は任意のバインダーを使用しても良い。また、混合工程では、鉄鉱石とバインダーに加えて、副原料として、石灰石やドロマイトなどを混合してもよい。また、副原料としては、焼成後の還元処理に使用される炉の種類に応じて、種々の還元剤や添加剤等を加えても良い。具体的には、還元剤として石炭やコークスなどの炭素材料があっても良い。 As the binder used during granulation, bentonite is preferred, but any known or arbitrary binder, such as organic or inorganic binders that provide similar effects, may be used. Further, in the mixing step, in addition to the iron ore and the binder, limestone, dolomite, or the like may be mixed as an auxiliary raw material. Further, as auxiliary raw materials, various reducing agents, additives, etc. may be added depending on the type of furnace used for the reduction treatment after firing. Specifically, a carbon material such as coal or coke may be used as the reducing agent.
　バインダーの量としては、混合物において、粉鉱石の質量をＷ１とし、バインダーの質量をＷ２として、
Ｗ２／Ｗ１×１００≧１．０
を満たす量であることが好ましい。上記範囲であれば、粉鉱石に対してバインダー量が好適であり、バインダーの効果が好適に得られ、強度が確保できる。上記範囲は、１．４以上であるのがより好ましく、１．６以上がさらに好ましい。バインダー量が多いほど、ペレット強度の確保が容易になるが、還元鉄の純度が下がるため、３．０以下の範囲にあることが好ましい。 The amount of binder in the mixture is as follows: W1 is the mass of fine ore, W2 is the mass of binder,
W2/W1×100≧1.0
It is preferable that the amount satisfies the following. Within the above range, the amount of binder is suitable for the fine ore, the effect of the binder can be suitably obtained, and the strength can be ensured. The above range is more preferably 1.4 or more, and even more preferably 1.6 or more. The larger the amount of binder, the easier it is to ensure pellet strength, but since the purity of reduced iron decreases, it is preferably in the range of 3.0 or less.
　鉄鉱石ペレットは、一般的な粉砕、混合、造粒、焼成工程によって製造する。粉砕工程は、一般的なボールミルなどの粉砕機を用いて良く、粉鉱石として用いる鉄鉱石にのみ行う。混合工程は、一般的なコンクリートミキサー等を用いてよい。造粒工程は、一般的なペレタイザーやドラムミキサーなどを用いて良い。焼成工程は、一般的なシャフト炉やロータリーキルンなどを用いて良い。 Iron ore pellets are manufactured by common crushing, mixing, granulation, and calcination processes. The pulverization process may be performed using a pulverizer such as a general ball mill, and is performed only on iron ore used as fine ore. A common concrete mixer or the like may be used in the mixing step. For the granulation process, a general pelletizer, drum mixer, etc. may be used. For the firing process, a general shaft furnace, rotary kiln, or the like may be used.
　造粒したグリーンペレットは、９．５～１２ｍｍ程度の大きさであることが好ましい。グリーンペレットの大きさが９．５ｍｍ未満の場合、焼成ペレットとして高炉内に充填した時の通気性が悪化してしまう。グリーンペレットの大きさが１２ｍｍを超えると、被還元性が低下してしまう。 The granulated green pellets preferably have a size of about 9.5 to 12 mm. If the size of the green pellets is less than 9.5 mm, air permeability will deteriorate when the green pellets are filled into a blast furnace as fired pellets. If the size of the green pellet exceeds 12 mm, the reducibility will decrease.
　鉄鉱石を１０５℃で２４ｈ乾燥した後に、ロータップを用いて１．０ｍｍ、２．８ｍｍ、４．８ｍｍ、６．７ｍｍ、８．０ｍｍ、９．５ｍｍの目開きを有する篩で篩分けを実施し、これらの篩上の鉄鉱石を核鉱石とした。表１に原料として使用した鉄鉱石の成分を示す。なお、Ｔ．Ｆｅは鉄鉱石中の全鉄量であり、ＬＯＩ（Ｌｏｓｓ ｏｎ Ｉｇｎｉｔｉｏｎ）は測定時の強熱減量である。上記と同じ組成の鉄鉱石を、同様に１０５℃で２４ｈ乾燥した後に、ボールミルで粉砕して得られた鉄鉱石粉を粉鉱石とした。粉鉱石は、１．０ｍｍの目開きを有する篩を全量通過するものであり、すなわち、１ｍｍ以下の粒度を有する。粉鉱石のブレーン指数は２５６０ｃｍ２／ｇであった。 After drying the iron ore at 105°C for 24 hours, it was sieved using a sieve with openings of 1.0 mm, 2.8 mm, 4.8 mm, 6.7 mm, 8.0 mm, and 9.5 mm using a low tap. The iron ore on these sieves was used as core ore. Table 1 shows the components of the iron ore used as a raw material. In addition, T. Fe is the total amount of iron in the iron ore, and LOI (Loss on Ignition) is the loss on ignition during measurement. Iron ore having the same composition as above was similarly dried at 105° C. for 24 hours and then ground in a ball mill to obtain iron ore powder. The entire amount of fine ore passes through a sieve with an opening of 1.0 mm, that is, it has a particle size of 1 mm or less. The Blaine index of the fine ore was 2560 cm 2 /g.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表２に示す質量比率で、核鉱石と粉鉱石の合計が５０００ｇとなるように準備し、所定割合のベントナイトと合わせて、コンクリートミキサーを使用して２０ｒｐｍで３ｍｉｎ混合した。鉄鉱石全体（核鉱石と粉鉱石の合計）に対するベントナイトの添加量（質量％）を表２の「ベントナイト割合」の欄に示す。次に、混合した原料を１．２ｍφのペレタイザーに入れて水を添加しながら造粒を実施した。９．５～１２ｍｍのペレット粒子を採取し、更に１０分ペレタイザーで転動させて、グリーンペレットを得た。なお、発明例では、１つのグリーンペレット内に含まれる核鉱石の数が平均して１．０になるように、核鉱石および粉鉱石の配合量を調整した。グリーンペレットに対する核鉱石の体積比及びグリーンペレット毎の核鉱石の数を表２に示す。なお、気孔率は３３％とした。 At the mass ratio shown in Table 2, core ore and fine ore were prepared so that the total amount was 5000 g, and mixed with bentonite at a predetermined ratio for 3 minutes at 20 rpm using a concrete mixer. The amount of bentonite added (mass %) to the entire iron ore (total of core ore and fine ore) is shown in the "bentonite ratio" column of Table 2. Next, the mixed raw materials were placed in a 1.2 mφ pelletizer and granulated while adding water. Pellet particles of 9.5 to 12 mm were collected and rolled in a pelletizer for an additional 10 minutes to obtain green pellets. In addition, in the invention example, the blending amounts of the core ore and fine ore were adjusted so that the number of core ores contained in one green pellet was 1.0 on average. Table 2 shows the volume ratio of core ore to green pellets and the number of core ores per green pellet. Note that the porosity was 33%.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　［落下強度測定］
　各発明例・比較例において、１０粒のグリーンペレットに対して、実操業における搬送、投入などを想定した落下強度測定を行った。高さ５０ｃｍからグリーンペレットを落下させる作業を繰り返し、グリーンペレットに亀裂又は破壊が確認されたら終了とした。終了する（すなわち亀裂または破壊が確認された回の）前の回数を落下強度として、１０粒の平均の落下強度を表２に示した。 [Fall strength measurement]
In each of the invention examples and comparative examples, drop strength measurements were performed on 10 green pellets assuming transportation, feeding, etc. in actual operation. The work of dropping green pellets from a height of 50 cm was repeated, and the test was terminated when cracks or destruction were observed in the green pellets. The average falling strength of 10 grains is shown in Table 2, with the number of times before the end (that is, the number of times when cracks or fractures were confirmed) being taken as the falling strength.
　［バースティング温度測定］
　各発明例・比較例において、グリーンペレットが炉内でバースティングする温度（以降、バースティング温度と記載する）を測定した。図３に、本実施例で用いた電気炉の概略を模式的に示す。グリーンペレット２００ｇが充填されたグリーンペレット充填カゴ３２を電気炉３０の中に設置し、流速１．２ｍ／ｓｅｃで２００℃（熱電対３４で測定）の熱風（空気）を加熱ガス源３６から流し、１０分間保持した。保持後、サンプルを取り出し、破裂の有無を確認した。破裂が確認されなかった場合、熱風の温度を４０℃刻みで上げて、新しいサンプルを炉に入れて同様の試験を繰り返した。サンプルの破裂が確認されたときの温度をバースティング温度とし、結果を表２に示した。 [Bursting temperature measurement]
In each invention example and comparative example, the temperature at which the green pellet bursts in the furnace (hereinafter referred to as bursting temperature) was measured. FIG. 3 schematically shows the outline of the electric furnace used in this example. A green pellet filling basket 32 filled with 200 g of green pellets is placed in an electric furnace 30, and hot air (air) at 200°C (measured with a thermocouple 34) is flowed from a heating gas source 36 at a flow rate of 1.2 m/sec. , and held for 10 minutes. After holding, the sample was taken out and checked for rupture. If no rupture was confirmed, the temperature of the hot air was increased in increments of 40°C, a new sample was placed in the furnace, and the same test was repeated. The temperature at which bursting of the sample was confirmed was defined as the bursting temperature, and the results are shown in Table 2.
　表２を参照して、同じベントナイト割合で発明例と比較例を比較すると、核鉱石を有している発明例のほうが、落下強度が高くなり、バースティング温度も高くなることが確認でき、発明の効果が明らかである。また、粒度の高い核鉱石の割合を増加させたり、ベントナイト割合を増加させたりすることで、強度およびバースティング温度が改善することが確認でき、より好適な製造条件となることが分かる。 Referring to Table 2, when comparing the invention example and the comparative example with the same bentonite ratio, it can be confirmed that the invention example having core ore has a higher fall strength and a higher bursting temperature. The effect is clear. Furthermore, it was confirmed that strength and bursting temperature were improved by increasing the proportion of core ore with a high particle size or by increasing the proportion of bentonite, and it was found that more suitable manufacturing conditions were achieved.
　本発明によれば、高強度であり、かつバースティングを抑制できるグリーンペレットが得られる鉄鉱石ペレットの製造方法を提供することができる。 According to the present invention, it is possible to provide a method for producing iron ore pellets that yields green pellets that have high strength and can suppress bursting.
　１０　１ｍｍ超えの粒度を有する核鉱石
　１２　１ｍｍ以下の粒度を有する粉鉱石
　１４　１ｍｍ以下の粒度を有する粉鉱石による凝集体の核
　３０　電気炉
　３２　グリーンペレット充填カゴ
　３４　熱電対
　３６　加熱ガス源 10 Core ore having a particle size exceeding 1 mm 12 Powder ore having a particle size of 1 mm or less 14 Nucleus of an aggregate of fine ore having a particle size of 1 mm or less 30 Electric furnace 32 Green pellet filling basket 34 Thermocouple 36 Heating gas source

Claims (10)

  1. 　全Ｆｅ量６３質量％以下の鉄鉱石とバインダーとを混合して、混合物を得る工程と、
    　前記混合物を造粒して、グリーンペレットを得る工程と、
    　前記グリーンペレットを焼成して、鉄鉱石ペレットを得る工程と、
    を有し、
    　前記鉄鉱石は、１ｍｍ超えの粒度を有する核鉱石と、１ｍｍ以下の粒度を有する粉鉱石と、を有することを特徴とする、鉄鉱石ペレットの製造方法。     A step of mixing iron ore with a total Fe content of 63% by mass or less and a binder to obtain a mixture;
    granulating the mixture to obtain green pellets;
    Calculating the green pellets to obtain iron ore pellets;
    has
    A method for producing iron ore pellets, wherein the iron ore includes a core ore having a particle size of more than 1 mm and a fine ore having a particle size of 1 mm or less.
  2. 　前記核鉱石の質量比率が、前記鉄鉱石に対して１５質量％以上である、請求項１に記載の鉄鉱石ペレットの製造方法。 The method for producing iron ore pellets according to claim 1, wherein the mass ratio of the core ore is 15% by mass or more with respect to the iron ore.
  3. 　前記核鉱石のうち、２．８ｍｍ超えの粒度を有する粒子の質量比率が、前記鉄鉱石に対して１５質量％以上である、請求項２に記載の鉄鉱石ペレットの製造方法。 The method for producing iron ore pellets according to claim 2, wherein the mass ratio of particles having a particle size of more than 2.8 mm in the core ore is 15% by mass or more based on the iron ore.
  4. 　前記核鉱石のうち、２．８ｍｍ超えの粒度を有する粒子の質量比率が、前記鉄鉱石に対して３０質量％以上である、請求項２に記載の鉄鉱石ペレットの製造方法。 The method for producing iron ore pellets according to claim 2, wherein the mass ratio of particles having a particle size of more than 2.8 mm in the core ore is 30% by mass or more based on the iron ore.
  5. 　前記核鉱石のうち、４．８ｍｍ超えの粒度を有する粒子の質量比率が、前記鉄鉱石に対して１０質量％以上である、請求項１に記載の鉄鉱石ペレットの製造方法。 The method for producing iron ore pellets according to claim 1, wherein the mass ratio of particles having a particle size of more than 4.8 mm in the core ore is 10% by mass or more based on the iron ore.
  6. 　前記核鉱石のうち、４．８ｍｍ超えの粒度を有する粒子の質量比率が、前記鉄鉱石に対して２５質量％以上である、請求項５に記載の鉄鉱石ペレットの製造方法。 The method for producing iron ore pellets according to claim 5, wherein the mass ratio of particles having a particle size of more than 4.8 mm in the core ore is 25% by mass or more based on the iron ore.
  7. 　前記鉄鉱石ペレット１つ当たりに含まれる前記核鉱石の個数が平均０．９～１．０となるように、前記核鉱石の粒度及び質量比率を設定する、請求項１～６のいずれか一項に記載の鉄鉱石ペレットの製造方法。 Any one of claims 1 to 6, wherein the particle size and mass ratio of the core ore are set so that the number of the core ore contained in each iron ore pellet is 0.9 to 1.0 on average. A method for producing iron ore pellets as described in section.
  8. 　鉄鉱石原料を１ｍｍの目開きを有する篩で篩い分けし、篩上を前記核鉱石として用い、篩下を粉砕して前記粉鉱石として用いる、請求項１～７のいずれか一項に記載の鉄鉱石ペレットの製造方法。 According to any one of claims 1 to 7, the iron ore raw material is sieved through a sieve having an opening of 1 mm, the upper part of the sieve is used as the core ore, and the lower part is crushed and used as the fine ore. Method for producing iron ore pellets.
  9. 　前記混合物において、前記粉鉱石の質量をＷ１とし、前記バインダーの質量をＷ２として、Ｗ２／Ｗ１×１００を１．０以上とする、請求項１～８のいずれか一項に記載の鉄鉱石ペレットの製造方法。 The iron ore pellet according to any one of claims 1 to 8, wherein in the mixture, the mass of the fine ore is W1, the mass of the binder is W2, and W2/W1×100 is 1.0 or more. manufacturing method.
  10. 　前記バインダーがベントナイトである、請求項１～９のいずれか一項に記載の鉄鉱石ペレットの製造方法。 The method for producing iron ore pellets according to any one of claims 1 to 9, wherein the binder is bentonite.
PCT/JP2023/025629 2022-09-16 2023-07-11 Method for producing iron ore pellet WO2024057693A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5527607B2 (en) * 1978-03-03 1980-07-22
JPS57200529A (en) * 1981-06-02 1982-12-08 Nippon Steel Corp Preparation of sintered ore having iron ore fine powder highly compounded therein
JPS63149336A (en) * 1986-12-15 1988-06-22 Nkk Corp Production of burnt agglomerated ore
JP2003293043A (en) * 2002-04-04 2003-10-15 Jfe Steel Kk Method for producing sintered ore for blast furnace

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5527607B2 (en) * 1978-03-03 1980-07-22
JPS57200529A (en) * 1981-06-02 1982-12-08 Nippon Steel Corp Preparation of sintered ore having iron ore fine powder highly compounded therein
JPS63149336A (en) * 1986-12-15 1988-06-22 Nkk Corp Production of burnt agglomerated ore
JP2003293043A (en) * 2002-04-04 2003-10-15 Jfe Steel Kk Method for producing sintered ore for blast furnace

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