JP6885386B2 - Manufacturing method of carbon material interior particles and manufacturing method of carbon material interior sintered ore - Google Patents

Manufacturing method of carbon material interior particles and manufacturing method of carbon material interior sintered ore Download PDF

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JP6885386B2
JP6885386B2 JP2018219090A JP2018219090A JP6885386B2 JP 6885386 B2 JP6885386 B2 JP 6885386B2 JP 2018219090 A JP2018219090 A JP 2018219090A JP 2018219090 A JP2018219090 A JP 2018219090A JP 6885386 B2 JP6885386 B2 JP 6885386B2
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一洋 岩瀬
一洋 岩瀬
山本　哲也
哲也 山本
隆英 樋口
隆英 樋口
友司 岩見
友司 岩見
頌平 藤原
頌平 藤原
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JFE Steel Corp
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本発明は、高炉などで製鉄原料として使用される焼結鉱の製造技術に関するものであり、具体的には、炭材を内装した炭材内装粒子の製造方法および当該炭材内装粒子を焼結原料の一部として製造される炭材内装焼結鉱の製造方法に関する。 The present invention relates to a technique for producing a sintered ore used as a raw material for iron making in a blast furnace or the like. The present invention relates to a method for producing a carbonaceous material interior sinter produced as a part of a raw material.

高炉製鉄法では、鉄源として焼結鉱や鉄鉱石、ペレットなどの鉄含有原料を主に用いている。ここで、焼結鉱は、塊成鉱の一種であり、以下の手順にて製造される。まず、粒径が１０ｍｍ以下の鉄鉱石やダスト等の鉄含有原料と、石灰石や生石灰、製鋼スラグなどの石灰含有原料と、精錬ニッケルスラグ、ドロマイト、蛇紋岩などのＭｇＯ含有原料と、珪石などからなるＳｉＯ２含有原料と、粉コークスや無煙炭などからなる凝結材と、から構成される造粒原料に適量の水を添加し、ドラムミキサーなどを用いて混合、造粒して擬似粒子とする。次いで、擬似粒子とした造粒原料を、焼結機の循環移動するパレットに装入し、造粒原料に含まれる凝結材を燃焼させて焼結ケーキとする。その後、焼結ケーキを、破砕、冷却、整粒し、一定の粒径以上のものを成品焼結鉱として回収している。 In the blast furnace ironmaking method, iron-containing raw materials such as sinter, iron ore, and pellets are mainly used as iron sources. Here, the sinter is a kind of agglomerate ore and is produced by the following procedure. First, from iron-containing raw materials such as iron ore and dust with a particle size of 10 mm or less, lime-containing raw materials such as limestone, fresh lime, and steelmaking slag, MgO-containing raw materials such as refined nickel slag, dolomite, and serpentine, and silica stone. An appropriate amount of water is added to a granulation raw material composed of a SiO 2- containing raw material and a coagulant made of powdered coke or smokeless coal, and the mixture is mixed and granulated using a drum mixer or the like to obtain pseudo-particles. Next, the granulated raw material made into pseudo particles is charged into a pallet that circulates and moves in the sintering machine, and the coagulant contained in the granulated raw material is burned to obtain a sintered cake. After that, the sintered cake is crushed, cooled, and sized, and those having a certain particle size or larger are recovered as a product sintered ore.

従来、焼結ベッド全体を均一に液相焼結する方法が主体であったが、近年、従来通り液相焼結主体の部分と、液相生成を抑えた部分とを焼結ベッドに混在させ、あえて不均一な構造を指向する焼結方法が検討されている。その理由は、融点が高く溶融しにくい部分は、焼成後には多くの細かい気孔が残存し、還元性ガスとの接触面積が増え、還元されやすい焼結鉱組織を形成することができるからである。 In the past, the main method was to uniformly sinter the entire sintered bed in liquid phase, but in recent years, as in the past, a portion mainly composed of liquid phase sintering and a portion in which liquid phase formation is suppressed are mixed in the sintered bed. However, a sintering method that aims at a non-uniform structure is being studied. The reason is that in the portion having a high melting point and being difficult to melt, many fine pores remain after firing, the contact area with the reducing gas increases, and a sintered ore structure that is easily reduced can be formed. ..

このような塊成鉱の製造方法として、特許文献１には、高融点で液相生成を抑えたものとして、炭材を鉄鉱石粉とＣａＯ含有原料で被覆した湿潤ペレットを作製し、これを従来の液相焼結主体の焼結原料に混合後、下方吸引型焼結機において焼結する方法が開示されている。 As a method for producing such agglomerate ore, Patent Document 1 describes wet pellets in which a carbonaceous material is coated with iron ore powder and a CaO-containing raw material as a method in which liquid phase formation is suppressed at a high melting point. A method of mixing with a sintering raw material mainly composed of liquid phase sintering and then sintering in a downward suction type sintering machine is disclosed.

特許第５７９０９６６号公報Japanese Patent No. 5790966

特許文献１に開示されたように、炭材内装焼結鉱は、炭材核を有する炭材内装粒子を、炭材核を有しない通常の造粒粒子に配合して焼結原料とし、焼結機で焼結することで製造される。しかしながら、炭材内装粒子が造粒機で造粒され、焼結機へ搬送、装入される工程で崩壊してしまうと、液相生成を抑えた部分が生成されず、還元されやすい焼結鉱組織を形成させることができない。本発明は上記課題を鑑みてなされたものであって、その目的は、焼結機へ搬送され、焼結機に装入される工程において炭材内装粒子の崩壊を抑制できる炭材内装粒子の製造方法を提供することにある。 As disclosed in Patent Document 1, in the carbonaceous material interior sinter, coal material interior particles having a carbonaceous material core are mixed with ordinary granulated particles having no carbon material core to be used as a sinter raw material and baked. Manufactured by sintering with a knot. However, if the carbonaceous material interior particles are granulated by the granulator and collapsed in the process of being transported to the sintering machine and charged, the portion where the liquid phase formation is suppressed is not generated and the sintering is easily reduced. It is not possible to form a mineral structure. The present invention has been made in view of the above problems, and an object of the present invention is to obtain carbonaceous material interior particles capable of suppressing the collapse of carbonaceous material interior particles in a process of being transported to a sintering machine and charged into the sintering machine. The purpose is to provide a manufacturing method.

このような課題を解決できる本発明の特徴は、以下の通りである。
（１）粉状の鉄含有原料と、石灰含有原料と、セメント粉と、を混合して混合粉とし、
前記混合粉と、炭材とを造粒して、炭材核の周囲に前記混合粉からなる外層が形成された炭材内装粒子を製造する、炭材内装粒子の製造方法。
（２）前記混合粉に対するセメント粉の配合割合が１質量％以上１０質量％以下になるように前記セメント粉を配合する、（１）に記載の炭材内装粒子の製造方法。
（３）（１）または（２）に記載の炭材内装粒子の製造方法で製造された炭材内装粒子を、鉄含有原料と、副原料と、凝結材と、を混合、造粒した造粒粒子に配合して焼結原料とし、前記焼結原料を焼結機のパレットに装入して焼結する、炭材内装焼結鉱の製造方法。 The features of the present invention that can solve such a problem are as follows.
(1) A powdered iron-containing raw material, a lime-containing raw material, and cement powder are mixed to form a mixed powder.
A method for producing carbonaceous material interior particles, wherein the mixed powder and the carbonaceous material are granulated to produce carbonaceous material interior particles in which an outer layer made of the mixed powder is formed around a carbon material core.
(2) The method for producing charcoal interior particles according to (1), wherein the cement powder is blended so that the blending ratio of the cement powder to the mixed powder is 1% by mass or more and 10% by mass or less.
(3) A product obtained by mixing and granulating an iron-containing raw material, an auxiliary raw material, and a coagulant from the carbonaceous material interior particles produced by the method for producing the carbon material interior particles according to (1) or (2). A method for producing a sinter for interior sinter, in which the sinter is mixed with granules to form a sinter raw material, and the sinter raw material is charged into a pallet of a sinter and sintered.

本発明の炭材内装焼結鉱の製造方法を実施することで、圧潰強度の高い炭材内装粒子を製造できるので、焼結機へ搬送され、焼結機に装入される工程において、崩壊する炭材内装粒子を少なくできる。そして、当該炭材内装粒子を含む焼結原料を焼結して炭材内装焼結鉱を製造することで、焼結鉱に還元されやすい焼結鉱組織が形成され、還元効率の向上が実現できる。 By implementing the method for producing a carbon material interior sintered ore of the present invention, carbon material interior particles having high crushing strength can be produced, so that they collapse in the process of being transported to the sintering machine and charged into the sintering machine. The number of carbonaceous material interior particles can be reduced. Then, by sintering the sintering raw material containing the sinter interior particles to produce the sinter for the sinter, a sinter structure that is easily reduced to the sinter is formed, and the reduction efficiency is improved. it can.

本実施形態に係る炭材内装粒子の製造方法が実施できる炭材内装粒子の製造工程１０の一例を示す模式図である。It is a schematic diagram which shows an example of the manufacturing process 10 of the carbonaceous material interior particle which can carry out the manufacturing method of the carbonaceous material interior particle which concerns on this embodiment. 混練機２８での混合時間と、造粒機３８で造粒された炭材内装粒子の圧潰強度分布との関係を示すグラフである。It is a graph which shows the relationship between the mixing time in a kneader 28, and the crushing intensity distribution of the carbonaceous material interior particles granulated by a granulation machine 38. 造粒機３８に存在する混合粉３０、コークス粒子３２（成長途中の炭材内装粒子を含む）および炭材内装粒子４０を示す写真である。It is a photograph which shows the mixed powder 30, the coke particle 32 (including the growing carbonaceous material interior particle), and the carbonaceous material interior particle 40 existing in the granulation machine 38. 炭材内装焼結鉱の製造方法が実施できる炭材内装焼結鉱の製造工程１００の一例を示す模式図である。It is a schematic diagram which shows an example of the manufacturing process 100 of the coal material interior sintered ore that can carry out the manufacturing method of the coal material interior sintered ore. 養生期間と炭材内装粒子の圧潰強度との関係を示すグラフである。It is a graph which shows the relationship between the curing period and the crushing strength of the carbonaceous material interior particles. セメント粉の配合割合と炭材内装粒子の圧潰強度との関係を示すグラフである。It is a graph which shows the relationship between the blending ratio of cement powder, and the crushing strength of carbonaceous material interior particles. セメント粉の配合割合と炭材内装焼結鉱の気孔率との関係を示すグラフである。It is a graph which shows the relationship between the blending ratio of cement powder, and the porosity of the carbonaceous interior sintered ore. 実施例および比較例の焼結鉱のＲＩを示すグラフである。It is a graph which shows the RI of the sinter of an Example and a comparative example.

以下、本発明の実施形態を通じて本発明を説明する。図１は、本実施形態に係る炭材内装粒子の製造方法が実施できる炭材内装粒子の製造工程１０の一例を示す模式図である。図１を用いて、本実施形態に係る炭材内装粒子の製造方法を説明する。 Hereinafter, the present invention will be described through embodiments of the present invention. FIG. 1 is a schematic view showing an example of a carbonaceous material interior particle manufacturing process 10 in which the method for producing carbonaceous material interior particles according to the present embodiment can be carried out. A method for producing the carbonaceous material interior particles according to the present embodiment will be described with reference to FIG.

炭材内装粒子の製造工程１０では、まず、貯蔵槽１４に貯蔵された鉄鉱石粉１２と、貯蔵槽１８に貯蔵された生石灰１６と、貯蔵槽２２に貯蔵されたセメント粉２０とがそれぞれの貯蔵槽から搬送機２４に所定量切り出される。鉄鉱石粉１２、生石灰１６およびセメント粉２０は、搬送機２４によってインテンシブミキサーなどの混練機２８に搬送される。搬送された鉄鉱石粉１２、生石灰１６およびセメント粉２０は、適量の水２６とともに混練機２８の内部で混合されて混合粉３０となる。 In the production process 10 of the carbonaceous material interior particles, first, the iron ore powder 12 stored in the storage tank 14, the quicklime 16 stored in the storage tank 18, and the cement powder 20 stored in the storage tank 22 are stored respectively. A predetermined amount is cut out from the tank to the conveyor 24. The iron ore powder 12, quicklime 16 and cement powder 20 are transported by the transporter 24 to a kneader 28 such as an intensive mixer. The conveyed iron ore powder 12, quicklime 16 and cement powder 20 are mixed together with an appropriate amount of water 26 inside the kneader 28 to form a mixed powder 30.

本実施形態において、鉄鉱石粉１２は、粉状の鉄含有原料の一例であり、例えば、粒径が１５０μｍ以下、比表面積が１５００ｃｍ２／ｇ程度の鉄鉱石粉や、製鉄所内で発生するダストやスラッジ等である。生石灰１６は、石灰含有原料の一例であり、生石灰に代えて、または生石灰とともに石灰石や消石灰を用いてもよい。但し、混合粉３０を造粒するという観点から、造粒効果の高い生石灰や消石灰を用いることが好ましい。また、焼結時に生じる融液の粘度を増加させるドロマイト［ＣａＭｇ（ＣＯ３）２］を生石灰および／または石灰石に添加してもよい。すなわち、石灰含有原料とは、生石灰、石灰石およびドロマイトの何れか１つ以上を含有する原料である。セメント粉２０は、水硬性のセメントであって、例えば、ポルトランドセメント、混合セメント、高炉スラグセメントなどである。なお、セメント粉２０には生石灰も含まれるので、セメント粉２０を加える場合には、セメント粉２０に含まれる生石灰の分だけ生石灰１６の切り出し量を減少させる。なお、以下の実施形態ではセメント粉２０として、以下の表１に示すポルトランドセメントを用いた。セメントは種類によって数か月の長期強度に差が有るが、本発明の用途では４週間かそれ以内の強度があればよく、数か月の長期強度は求められていない。このため、本実施形態では、いずれの種類のセメントも用いることができる。なお、寒冷地などではアルミナセメントを用いることでさらに短時間で強度が発現するので、より好ましい。 In the present embodiment, the iron ore powder 12 is an example of a powdery iron-containing raw material, for example, iron ore powder having a particle size of 150 μm or less and a specific surface area of about 1500 cm 2 / g, and dust and sludge generated in a steel mill. And so on. Quicklime 16 is an example of a lime-containing raw material, and limestone or slaked lime may be used instead of quicklime or together with quicklime. However, from the viewpoint of granulating the mixed powder 30, it is preferable to use quicklime or slaked lime having a high granulation effect. In addition, dolomite [CaMg (CO 3 ) 2 ], which increases the viscosity of the melt produced during sintering, may be added to quicklime and / or limestone. That is, the lime-containing raw material is a raw material containing any one or more of quicklime, limestone and dolomite. The cement powder 20 is a hydraulic cement, such as Portland cement, mixed cement, and blast furnace slag cement. Since the cement powder 20 also contains quicklime, when the cement powder 20 is added, the amount of quicklime 16 cut out is reduced by the amount of the quicklime contained in the cement powder 20. In the following embodiment, Portland cement shown in Table 1 below was used as the cement powder 20. Although the long-term strength of cement varies depending on the type, the strength of the present invention may be as long as 4 weeks or less, and the long-term strength of several months is not required. Therefore, in this embodiment, any kind of cement can be used. In cold regions, it is more preferable to use alumina cement because the strength is developed in a shorter time.

Figure 0006885386
Figure 0006885386

混練機２８では各原料を混練機２８で十分に混合し、各原料を均一に分散させることが好ましい。これにより、炭材内装粒子４０の品質を安定させることができる。例えば、生石灰１６の分散が不十分となり、炭材内装粒子に設定品位よりも生石灰１６が過剰に配合されると、後の焼結工程で炭材核の周囲の外層が溶融してしまい炭材内装焼結鉱を得られない場合がある。また、セメント粉２０の分散が不十分となり、炭材内装粒子に配合されるセメント粉２０の配合量が設定品位よりも不足すると、搬送等のハンドリングに耐える十分な強度が得られず、歩留りが低下するおそれがある。さらに、水２６の分散が不十分となると、後の造粒機３８による造粒に支障をきたすおそれがある。 In the kneading machine 28, it is preferable that each raw material is sufficiently mixed in the kneading machine 28 and each raw material is uniformly dispersed. Thereby, the quality of the carbonaceous material interior particles 40 can be stabilized. For example, if the dispersion of quicklime 16 becomes insufficient and the quicklime 16 is excessively blended in the carbon material interior particles in an amount higher than the set grade, the outer layer around the coal material core is melted in the subsequent sintering step, and the carbon material is used. Interior sintered ore may not be obtained. Further, if the dispersion of the cement powder 20 is insufficient and the amount of the cement powder 20 blended in the carbonaceous material interior particles is less than the set grade, sufficient strength to withstand handling such as transportation cannot be obtained, and the yield is low. It may decrease. Further, if the water 26 is not sufficiently dispersed, the granulation by the subsequent granulator 38 may be hindered.

図２は、混練機２８での混合時間と、造粒機３８で造粒された炭材内装粒子の圧潰強度分布との関係を示すグラフである。図２において、横軸は、セメント養生４週間後の炭材内装粒子の圧潰強度（Ｎ／個）であり、縦軸は頻度（個）である。図２の点線は、混練機２８で各原料を混合せずに造粒機３８を用いて炭材内装粒子に造粒し、その後、セメント養生を４週間行った後の炭材内装粒子の圧潰強度の分布を示す。破線は、混練機２８で各原料を１０秒間混合した混合粉を、造粒機３８を用いて炭材内装粒子に造粒し、その後、セメント養生を４週間行った後の炭材内装粒子の圧潰強度の分布を示す。実線は、混練機２８で各原料を６０秒間混合した混合粉を、造粒機３８を用いて炭材内装粒子に造粒し、その後、セメント養生を４週間行った後の炭材内装粒子の圧潰強度の分布を示す。なお、混練機２８に各原料が連続的に装入され、混練が連続的になされる場合の混合時間は、混練機２８内部の各原料の滞留量を装入速度で除することで算出できる。 FIG. 2 is a graph showing the relationship between the mixing time in the kneading machine 28 and the crushing intensity distribution of the carbonaceous material interior particles granulated by the granulating machine 38. In FIG. 2, the horizontal axis is the crushing strength (N / piece) of the carbonaceous material interior particles after 4 weeks of cement curing, and the vertical axis is the frequency (pieces). The dotted line in FIG. 2 shows the crushing of the carbonaceous interior particles after granulating the carbonaceous interior particles using the granulator 38 without mixing the raw materials with the kneader 28 and then performing the cement curing for 4 weeks. Shows the intensity distribution. The broken line indicates that the mixed powder obtained by mixing each raw material for 10 seconds with the kneader 28 is granulated into the carbonaceous interior particles using the granulator 38, and then cement-cured for 4 weeks. The distribution of crushing strength is shown. The solid line shows the mixture powder obtained by mixing each raw material for 60 seconds with the kneader 28, granulated into the carbonaceous interior particles using the granulator 38, and then cement-cured for 4 weeks. The distribution of crushing strength is shown. The mixing time when each raw material is continuously charged into the kneading machine 28 and the kneading is continuously performed can be calculated by dividing the retention amount of each raw material inside the kneading machine 28 by the charging speed. ..

図２に示すように、混合を全く行わない場合、圧潰強度の分布幅が広くなり、比較的低強度の炭材内装粒子が多く確認された。混合を１０秒間行うと、混合を全く行わない場合よりも低強度の炭材内装粒子が減少した。混合を６０秒間行うと、さらに、低強度の炭材内装粒子が減少して高強度の炭材内装粒子が増加し、圧潰強度の分布幅も狭くなった。この時の混合仕事率は３３０Ｗ／ｋｇであった。なお、混合仕事率は、混合機の消費電力÷混合物の質量から算出した。また、混合を１０秒間行った場合の混合エネルギーは、３３００Ｊ／ｋｇであり、混合を６０秒間行った場合の混合エネルギーは、１９８００Ｊ／ｋｇであった。この結果から、混練機２８で各原料を均一に混合することで、炭材内装粒子の強度品質が高まるとともに強度品質が均一化され、炭材内装粒子の品質を安定化できることがわかる。なお、各原料を十分に混合できる混合時間は、炭材内装焼結鉱の製造に用いる原料、混練機および造粒機を用いて図２に示したような混合時間と圧潰強度の分布との関係を確認することで定めることができる。 As shown in FIG. 2, when no mixing was performed, the distribution width of the crushing strength became wide, and many relatively low-strength carbonaceous material interior particles were confirmed. When the mixing was performed for 10 seconds, the low-strength carbonaceous material interior particles were reduced as compared with the case where the mixing was not performed at all. When the mixing was carried out for 60 seconds, the low-strength carbonaceous material interior particles further decreased, the high-strength carbonaceous material interior particles increased, and the distribution width of the crushing strength became narrow. The mixed power at this time was 330 W / kg. The mixing power was calculated from the power consumption of the mixer divided by the mass of the mixture. The mixing energy when the mixing was carried out for 10 seconds was 3300 J / kg, and the mixed energy when the mixing was carried out for 60 seconds was 19,800 J / kg. From this result, it can be seen that by uniformly mixing each raw material with the kneader 28, the strength quality of the carbonaceous material interior particles is enhanced, the strength quality is made uniform, and the quality of the carbonaceous material interior particles can be stabilized. The mixing time at which each raw material can be sufficiently mixed is the mixing time and the distribution of crushing strength as shown in FIG. 2 using the raw materials used for producing the carbonaceous interior sintered ore, the kneader and the granulator. It can be determined by confirming the relationship.

次に、混練機２８で混合された混合粉３０と、貯蔵槽３４に貯蔵されたコークス粒子３２と、が搬送機３６に所定量切り出され、造粒原料となる。本実施形態では、造粒原料に対するコークス粒子３２の配合割合が１質量％以上５質量％以下、より好ましくは、２質量％以上４質量％以下になるように、混合粉３０およびコークス粒子３２を切り出している。 Next, the mixed powder 30 mixed by the kneader 28 and the coke particles 32 stored in the storage tank 34 are cut out in a predetermined amount by the conveyor 36 and used as a raw material for granulation. In the present embodiment, the mixed powder 30 and the coke particles 32 are mixed so that the blending ratio of the coke particles 32 with respect to the granulation raw material is 1% by mass or more and 5% by mass or less, more preferably 2% by mass or more and 4% by mass or less. It is cut out.

本実施形態において、コークス粒子３２は、炭材の一例であり、当該炭材は、周囲に混合粉３０からなる外層が形成されて炭材核となる。炭材として無煙炭であるホンゲイ炭を用いてもよい。コークス粒子およびホンゲイ炭は揮発分が少ないので、これらを用いることで焼結時に炭材から生じる燃焼ガスが少なくでき、当該炭材内装粒子を用いて製造される炭材内装焼結鉱の強度低下が抑制される。これにより、炭材内装焼結鉱の歩留低下を抑制できる。 In the present embodiment, the coke particles 32 are an example of a charcoal material, and the coke material has an outer layer made of a mixed powder 30 formed around the coke material to form a core of the charcoal material. Anthracite charcoal, Hongei charcoal, may be used as the charcoal material. Since coke particles and Hongei charcoal have low volatile content, the amount of combustion gas generated from the coal material during sintering can be reduced by using them, and the strength of the coal material interior sintered ore produced using the carbon material interior particles is reduced. Is suppressed. As a result, it is possible to suppress a decrease in the yield of the sinter for the interior of the carbonaceous material.

造粒原料は、搬送機３６によってディスクペレタイザーなどの造粒機３８に搬送される。造粒原料は、造粒機３８で適量の水２６とともに転動され、水の架橋力等によってコークス粒子３２が炭材核となり、その周囲に混合粉３０からなる外層が形成された炭材内装粒子４０が製造される。 The granulation raw material is conveyed by the transfer machine 36 to a granulation machine 38 such as a disc pelletizer. The granulation raw material is rolled together with an appropriate amount of water 26 by the granulator 38, and the coke particles 32 become the carbon material core due to the cross-linking force of water or the like, and the outer layer composed of the mixed powder 30 is formed around the coke material interior. Particle 40 is produced.

図３は、造粒機３８に存在する混合粉３０、コークス粒子３２（成長途中の炭材内装粒子を含む）および炭材内装粒子４０を示す写真である。図１に示した炭材内装粒子の製造工程１０に従って炭材内装粒子４０が製造されるが、炭材内装粒子４０の強度が低いと、炭材内装粒子４０を焼結機へ搬送し、焼結機に装入される工程で崩壊する。このため、本実施形態に係る炭材内装粒子の製造方法では、鉄鉱石粉１２および生石灰１６にセメント粉２０を配合している。これにより、コークス粒子３２の周囲に外層として形成される混合粉３０の強度が高められ、焼結機へ搬送し、焼結機に装入される工程における炭材内装粒子４０の崩壊を抑制できる。 FIG. 3 is a photograph showing the mixed powder 30, coke particles 32 (including growing carbonaceous material interior particles), and carbonaceous material interior particles 40 existing in the granulator 38. The carbonaceous material interior particles 40 are produced according to the production process 10 of the carbonaceous material interior particles shown in FIG. 1. However, if the strength of the carbon material interior particles 40 is low, the carbon material interior particles 40 are conveyed to the sintering machine and baked. It collapses in the process of being charged into the knot. Therefore, in the method for producing the carbonaceous material interior particles according to the present embodiment, the cement powder 20 is blended with the iron ore powder 12 and the quicklime 16. As a result, the strength of the mixed powder 30 formed as an outer layer around the coke particles 32 is increased, and it is possible to suppress the collapse of the carbonaceous material interior particles 40 in the process of transporting the mixed powder 30 to the sintering machine and charging the coke particles 32 into the sintering machine. ..

図４は、炭材内装焼結鉱の製造方法が実施できる炭材内装焼結鉱の製造工程１００の一例を示す模式図である。炭材内装焼結鉱の製造工程１００では、図１に示した炭材内装粒子の製造工程１０と平行して、粒径が１０ｍｍ以下の鉄鉱石やダスト等の鉄含有原料と、石灰石、生石灰、製鋼スラグなどのＣａＯ含有原料を含む副原料と、粒径３ｍｍ未満の粉コークスや無煙炭などからなる凝結材と、を含む原料５０を、ドラムミキサー等の造粒機５２で造粒して造粒粒子とする。なお、副原料には、精錬ニッケルスラグ、ドロマイト、蛇紋岩などのＭｇＯ含有原料や、珪石などからなるＳｉＯ２含有原料が含まれてもよい。 FIG. 4 is a schematic view showing an example of a production process 100 of a carbon material interior sinter in which a method for producing a carbon material interior sinter can be carried out. In the production process 100 of the carbon material interior sintered ore, in parallel with the production process 10 of the carbon material interior particles shown in FIG. 1, iron-containing raw materials such as iron ore and dust having a particle size of 10 mm or less, limestone, and fresh lime. , A raw material 50 containing an auxiliary raw material containing a CaO-containing raw material such as steelmaking slag and a coagulant made of powdered coke or smokeless charcoal having a particle size of less than 3 mm is granulated by a granulator 52 such as a drum mixer. Let it be a grain size. The auxiliary raw material may include an MgO-containing raw material such as refined nickel slag, dolomite, and serpentinite, and a SiO 2- containing raw material made of silica stone or the like.

次いで、原料５０を造粒した造粒粒子に、炭材内装粒子４０を配合して焼結原料とする。焼結原料のうち、原料５０を造粒した造粒粒子が液相焼結主体の部分となり、炭材内装粒子４０が液相生成を抑えた部分となる。焼結原料に対する炭材内装粒子４０の配合割合が１０質量％以上３０質量％以下になるように、造粒粒子に炭材内装粒子４０を配合することが好ましい。これにより、焼結原料の通気性が向上し、炭材内装焼結鉱の生産性が向上する。 Next, the carbonaceous material interior particles 40 are mixed with the granulated particles obtained by granulating the raw material 50 to obtain a sintered raw material. Of the sintering raw materials, the granulated particles obtained by granulating the raw material 50 serve as a portion mainly composed of liquid phase sintering, and the carbonaceous material interior particles 40 serve as a portion in which liquid phase formation is suppressed. It is preferable to add the carbonaceous material interior particles 40 to the granulated particles so that the mixing ratio of the carbonaceous material interior particles 40 with respect to the sintering raw material is 10% by mass or more and 30% by mass or less. As a result, the air permeability of the sinter raw material is improved, and the productivity of the carbonaceous interior sinter is improved.

炭材内装粒子が配合された焼結原料は、下方吸引式焼結機６０のサージホッパーに搬入される。焼結原料は、サージホッパーから無端移動式のパレットに装入され、装入層が形成される。装入層は、上方に設置された点火炉によって点火され、下方に設置されたウインドボックスから上方のガスを下方に吸引されることで装入層は順次燃焼、焼結される。装入層は、当該燃焼により発生する燃焼熱で焼結されて焼結ケーキとなる。焼結ケーキは、排鉱部で破砕および整粒され、粒径４ｍｍ以上の塊成物が成品の炭材内装焼結鉱として回収される。このようにして製造された炭材内装焼結鉱が高炉７０の製鉄原料として使用される。なお、本実施形態における粒径とは、ＪＩＳ（日本工業規格） Ｚ ８８０１−１に準拠した公称目開きの篩を用いて篩分けされた粒径であり、例えば、粒径４ｍｍ以上とは、ＪＩＳ Ｚ ８８０１−１に準拠した公称目開き４ｍｍの篩を用いて篩上に篩分けされる粒径をいう。 The sintering raw material containing the carbonaceous material interior particles is carried into the surge hopper of the downward suction type sintering machine 60. The sintered raw material is charged from the surge hopper into an endlessly movable pallet to form an charged layer. The charge layer is ignited by an ignition furnace installed above, and the upper gas is sucked downward from the wind box installed below, so that the charge layer is sequentially burned and sintered. The charging layer is sintered by the heat of combustion generated by the combustion to form a sintered cake. The sintered cake is crushed and sized at the sinter part, and agglomerates having a particle size of 4 mm or more are recovered as a finished coal material interior sinter. The carbonaceous interior sintered ore produced in this way is used as a raw material for steelmaking in the blast furnace 70. The particle size in the present embodiment is a particle size obtained by sieving using a sieve having a nominal opening according to JIS (Japanese Industrial Standards) Z 8801-1, and for example, a particle size of 4 mm or more is defined as a particle size of 4 mm or more. The particle size that is sieved onto a sieve using a sieve with a nominal opening of 4 mm in accordance with JIS Z 8801-1.

本実施形態に係る炭材内装粒子の製造方法で用いるコークス粒子３２の粒径は、２ｍｍ以上であることが好ましい。粒径が２ｍｍ以上のコークス粒子を用いることで、炭材内装粒子を配合した焼結原料を焼結機で焼結する工程でコークス粒子が消失してしまうことを抑制できる。コークス粒子３２の粒径は、３ｍｍ以上であることがより好ましい。粒径が３ｍｍ以上の炭材を用いることで、コークス粒子の消失をさらに抑制できる。 The particle size of the coke particles 32 used in the method for producing the carbonaceous material interior particles according to the present embodiment is preferably 2 mm or more. By using coke particles having a particle size of 2 mm or more, it is possible to prevent the coke particles from disappearing in the step of sintering the sintering raw material containing the carbonaceous material interior particles with a sintering machine. The particle size of the coke particles 32 is more preferably 3 mm or more. By using a carbonaceous material having a particle size of 3 mm or more, the disappearance of coke particles can be further suppressed.

一方、粒径が大きいコークス粒子を用いると、焼結時にコークスから発生する燃焼ガス量が増加し、炭材内装焼結鉱においてコークス粒子を被覆する外層に亀裂が生じる。コークス粒子を被覆する外層に亀裂が生じると炭材内装焼結鉱の強度が大きく低下し、この結果、炭材内装焼結鉱の歩留が大きく低下する。このため、コークス粒子３２の粒径は、８ｍｍ以下であることが好ましく、６ｍｍ以下であることがより好ましい。 On the other hand, when coke particles having a large particle size are used, the amount of combustion gas generated from coke during sintering increases, and cracks occur in the outer layer covering the coke particles in the carbonaceous interior sintered ore. When the outer layer covering the coke particles is cracked, the strength of the carbonaceous interior sinter is greatly reduced, and as a result, the yield of the carbonaceous interior sinter is significantly reduced. Therefore, the particle size of the coke particles 32 is preferably 8 mm or less, and more preferably 6 mm or less.

また、製造される炭材内装粒子４０の粒径は、８ｍｍ以上１８ｍｍ以下であることが好ましい。上述したように、粒径が４ｍｍ以上の炭材内装焼結鉱が成品焼結鉱として回収され、粒径４ｍｍ未満の焼結鉱は、焼結原料にリサイクル（返鉱）される。また、炭材内装粒子４０は、焼結機で焼結すると水分の蒸発や部分的な溶融によって体積が小さくなる。従って、炭材内装粒子４０がそのまま焼結されたとしても返鉱にならないように、炭材内装粒子４０の粒径は、８ｍｍ以上であることが好ましく、１０ｍｍ以上であることがより好ましい。 Further, the particle size of the produced carbonaceous material interior particles 40 is preferably 8 mm or more and 18 mm or less. As described above, the carbonaceous interior sinter having a particle size of 4 mm or more is recovered as a product sinter, and the sinter having a particle size of less than 4 mm is recycled (returned) into a sintering raw material. Further, when the carbonaceous material interior particles 40 are sintered by a sintering machine, the volume becomes smaller due to evaporation of water or partial melting. Therefore, the particle size of the carbonaceous material interior particles 40 is preferably 8 mm or more, and more preferably 10 mm or more so that even if the carbonaceous material interior particles 40 are sintered as they are, they do not return ore.

一方、炭材内装粒子４０に形成されたコークス粒子３２の外層の厚さが５ｍｍを超えると、限られた焼結時間内に炭材内装粒子４０の全ての外層を焼結することが困難になる。焼結が不十分な部分が炭材内装焼結鉱に存在すると、炭材内装焼結鉱の強度は低下し、炭材内装焼結鉱の歩留が低下する。従って、炭材内装粒子４０の外層の厚さは５ｍｍ以下であることが好ましく、例えば、コークス粒子３２の粒径が８ｍｍであって外層の厚さが５ｍｍである場合の炭材内装粒子の粒径は１８ｍｍになる。このため、炭材内装粒子４０の粒径は１８ｍｍ以下であることが好ましい。 On the other hand, if the thickness of the outer layer of the coke particles 32 formed on the carbon material interior particles 40 exceeds 5 mm, it becomes difficult to sinter all the outer layers of the carbon material interior particles 40 within a limited sintering time. Become. If a portion of insufficient sintering is present in the sinter for the interior of the carbonaceous material, the strength of the sinter for the interior of the carbonaceous material decreases, and the yield of the sinter for the interior of the carbon material decreases. Therefore, the thickness of the outer layer of the carbonaceous material interior particles 40 is preferably 5 mm or less. For example, the particles of the carbonaceous material interior particles when the particle size of the coke particles 32 is 8 mm and the thickness of the outer layer is 5 mm. The diameter will be 18 mm. Therefore, the particle size of the carbonaceous material interior particles 40 is preferably 18 mm or less.

本実施形態に係る炭材内装粒子の製造方法では、混合粉にセメント粉２０を配合し、これにより製造される炭材内装粒子４０の強度を高めている。セメント粉は安価なので、焼結鉱の製造といった大量生産プロセスに用いることで、製造コスト抑制効果が高くなる。 In the method for producing carbon material interior particles according to the present embodiment, cement powder 20 is blended with the mixed powder to increase the strength of the carbon material interior particles 40 produced by the cement powder 20. Since cement powder is inexpensive, its production cost control effect is enhanced by using it in a mass production process such as the production of sinter.

次に、炭材内装粒子４０の強度について説明する。炭材内装粒子４０が製造されてから下方吸引式焼結機６０に装入されるまでに、炭材内装粒子４０は、複数の搬送コンベアを乗り継ぐ。このため、炭材内装粒子４０は、複数の搬送コンベアの乗り継ぎと、下方吸引式焼結機６０のパレット装入時の衝撃に耐える強度を有することが好ましい。まず、圧潰強度を変えた炭材内装粒子を試験的に製造し、搬送コンベアの乗り継ぎとパレット装入を行った後における炭材内装粒子の崩壊状況を確認した。その結果、炭材内装粒子の圧潰強度を９．８Ｎ／個以上にすることで、複数の搬送コンベアの乗り継ぎと、下方吸引式焼結機６０のパレット装入時の衝撃に耐え、下方吸引式焼結機６０への直送が可能になることが判明した。なお、本実施形態において、圧潰強度とは、圧縮試験機を用いて、圧縮速度１ｍｍ／ｍｉｎで炭材内装粒子を圧縮して測定される最大強度である。 Next, the strength of the carbonaceous material interior particles 40 will be described. From the time when the carbon material interior particles 40 are manufactured to the time when they are charged into the downward suction type sintering machine 60, the carbon material interior particles 40 transfer to a plurality of conveyors. Therefore, it is preferable that the carbonaceous material interior particles 40 have a strength to withstand the connection between a plurality of conveyors and the impact at the time of loading the pallet of the downward suction type sintering machine 60. First, the carbonaceous interior particles having different crushing strengths were experimentally produced, and the decay state of the carbonaceous interior particles after the transfer of the conveyor and the pallet loading was confirmed. As a result, by setting the crushing strength of the carbonaceous material interior particles to 9.8 N / piece or more, it can withstand the impact of connecting multiple conveyors and loading the pallet of the downward suction type sintering machine 60, and is a downward suction type. It has been found that direct delivery to the sintering machine 60 is possible. In the present embodiment, the crushing strength is the maximum strength measured by compressing the carbonaceous material interior particles at a compression rate of 1 mm / min using a compression tester.

炭材内装粒子の圧潰強度を９．８Ｎ／個以上にするには、ヘマタイトを主体鉱物とする鉄鉱石粉であれば、１８００〜２０００ｃｍ２／ｇ程度のＢｌａｉｎｅ比表面積または粒径４５μｍ以下となる鉄鉱石粉の含有割合が８０質量％以上となる鉄鉱石粉を使用する必要がある。しかしながら、現在、鉄鉱石市場で流通しているヘマタイト精鉱微粉の多くは、Ｂｌａｉｎｅ比表面積が５００〜１５００ｃｍ２／ｇ程度、４５μｍ以下となる鉄鉱石粉の含有割合が３５〜７５質量％程度である。従って、これら原料をこのまま用いても圧潰強度９．８Ｎ／個以上の炭材内装粒子を製造できない。 In order to increase the crushing strength of the carbonaceous material interior particles to 9.8 N / piece or more, in the case of iron ore powder containing hematite as the main mineral, iron ore having a Braine specific surface area of about 1800 to 2000 cm 2 / g or a particle size of 45 μm or less. It is necessary to use iron ore powder having a stone powder content of 80% by mass or more. However, most of the hematite concentrate fine powder currently distributed in the iron ore market has a Braine specific surface area of about 500 to 1500 cm 2 / g and a content ratio of iron ore powder of about 45 μm or less of about 35 to 75% by mass. .. Therefore, even if these raw materials are used as they are, it is not possible to produce carbonaceous material interior particles having a crushing strength of 9.8 N / piece or more.

一方、ボールミル等を用いて鉄鉱石粉を粉砕することで、１８００ｃｍ２／ｇ以上のＢｌａｉｎｅ比表面積または粒径４５μｍ以下となる鉄鉱石粉の含有割合が８０質量％以上が達成できるが、設備コストやランニングコストが高くなる。そこで、炭材の周囲に形成される外層の混合粉３０にセメント粉２０を配合し、炭材内装粒子の圧潰強度を９．８Ｎ／個以上にできるか否かを確認するべく、図１に示した炭材内装粒子の製造工程１０に従って、炭材内装粒子の製造試験を行った。 On the other hand, by crushing the iron ore powder using a ball mill or the like, the content ratio of the iron ore powder having a Braine specific surface area of 1800 cm 2 / g or more or a particle size of 45 μm or less can be achieved of 80% by mass or more, but the equipment cost and running can be achieved. The cost is high. Therefore, in order to confirm whether or not the crushing strength of the carbon material interior particles can be increased to 9.8 N / piece or more by blending the cement powder 20 with the outer layer mixed powder 30 formed around the carbon material, FIG. 1 shows. The production test of the carbonaceous material interior particles was performed according to the production step 10 of the carbonaceous material interior particles shown.

炭材内装粒子の製造試験は、以下の手順にて実施した。まず、粒径１５０μｍ以下であってＢｌａｉｎｅ比表面積が１５００ｃｍ２／ｇの鉄鉱石粉と、粒径７５μｍ以下の生石灰と、粒径１５０μｍ以下のセメント粉とを、質量比で９５：１：４の割合で配合し、インテンシブミキサーを用いて均一に混合して混合粉とした。この混合粉と、粒径２ｍｍ以上８ｍｍ以下のコークス粒子を質量比９８：２の割合で配合して造粒原料とした。この造粒原料を、ディスクペレタイザーを用いて転動させて造粒原料を造粒し、炭材の周囲に混合粉からなる外層が形成された炭材内装粒子を製造した。造粒原料の造粒に必要な水は、インテンシブミキサーおよびディスクペレタイザー内へ適量噴霧して供給した。 The production test of the carbonaceous material interior particles was carried out according to the following procedure. First, iron ore powder having a particle size of 150 μm or less and a Braine specific surface area of 1500 cm 2 / g, quicklime having a particle size of 75 μm or less, and cement powder having a particle size of 150 μm or less are mixed in a mass ratio of 95: 1: 4. And mixed uniformly using an intensive mixer to obtain a mixed powder. This mixed powder and coke particles having a particle size of 2 mm or more and 8 mm or less were mixed at a mass ratio of 98: 2 to prepare a granulation raw material. This granulation raw material was rolled using a disc pelletizer to granulate the granulation raw material, and carbon material inner particles in which an outer layer made of a mixed powder was formed around the carbon material were produced. The water required for granulation of the granulation raw material was supplied by spraying an appropriate amount into the intensive mixer and the disc pelletizer.

図５は、養生期間と炭材内装粒子の圧潰強度との関係を示すグラフである。図５において、横軸は養生期間（Ｗｅｅｋ）であり、縦軸は炭材内装粒子の圧潰強度（Ｎ／個）である。また、図５において、（ ）内の値は、炭材内装粒子の水分含有割合（質量％）を示し、白丸プロットは圧潰強度の実測値を示し、黒丸プロットは圧潰強度の平均値を示す。図５に示すように、養生後数日で炭材内装粒子の圧潰強度は９．８Ｎ／個以上となった。また、養生後に重機やリクレーマーでハンドリングしたとしても崩壊しない圧潰強度である４９Ｎ／個以上とするには、養生期間を３週間以上にすればよいことがわかった。 FIG. 5 is a graph showing the relationship between the curing period and the crushing strength of the carbonaceous material interior particles. In FIG. 5, the horizontal axis represents the curing period (Week), and the vertical axis represents the crushing strength (N / piece) of the carbonaceous material interior particles. Further, in FIG. 5, the values in parentheses indicate the water content ratio (mass%) of the carbonaceous material interior particles, the white circle plot shows the measured value of the crushing strength, and the black circle plot shows the average value of the crushing strength. As shown in FIG. 5, the crushing strength of the carbonaceous material interior particles became 9.8 N / piece or more within a few days after curing. It was also found that the curing period should be 3 weeks or more in order to achieve a crushing strength of 49 N / piece or more that does not collapse even when handled with a heavy machine or a reclaimer after curing.

この結果から、Ｂｌａｉｎｅ比表面積が１８００ｃｍ２／ｇ未満または粒径４５μｍ以下となる鉄鉱石粉の含有割合が８０質量％未満の鉄鉱石粉を用いた場合であっても、当該鉄鉱石粉を含む混合粉に対するセメント粉の配合割合が４質量％となるようにセメント粉を配合することで、炭材内装粒子の圧潰強度を９．８Ｎ／個以上の圧潰強度を有する炭材内装粒子を製造できることが確認された。一方、セメント粉を配合しない場合には、炭材内装粒子の圧潰強度は２．０〜３．９Ｎ／個となり、９．８Ｎ／個以上の圧潰強度にできなかった。 From this result, even when the iron ore powder having a specific surface area of less than 1800 cm 2 / g or a particle size of 45 μm or less and the content ratio of the iron ore powder of less than 80% by mass is used, the mixed powder containing the iron ore powder is used. It was confirmed that by blending the cement powder so that the blending ratio of the cement powder is 4% by mass, it is possible to produce the carbonaceous interior particles having a crushing strength of 9.8 N / piece or more. It was. On the other hand, when the cement powder was not blended, the crushing strength of the carbonaceous material interior particles was 2.0 to 3.9 N / piece, and the crushing strength could not be 9.8 N / piece or more.

次に、混合原料に対するセメント粉の配合割合について説明する。混合原料に対するセメント粉の配合割合を０〜６質量％に変えて炭材内装粒子を製造し、各炭材内装粒子の圧潰強度を測定した。なお、セメント粉の配合割合を増やした場合には、その分だけ、鉄鉱石粉の配合割合を減じて調整した。炭材内装粒子の圧潰強度の測定結果を図６に示す。 Next, the mixing ratio of cement powder to the mixed raw material will be described. The carbonaceous material interior particles were produced by changing the mixing ratio of cement powder to the mixed raw material to 0 to 6% by mass, and the crushing strength of each carbon material internal particle was measured. When the mixing ratio of cement powder was increased, the mixing ratio of iron ore powder was reduced accordingly. FIG. 6 shows the measurement results of the crushing strength of the carbonaceous material interior particles.

図６は、セメント粉の配合割合と炭材内装粒子の圧潰強度との関係を示すグラフである。図６において、横軸は混合粉に対するセメント粉の配合割合（質量％）であり、縦軸はセメント養生を４週間行った後の炭材内装粒子の圧潰強度（Ｎ／個）である。図６に示すように、混合粉に対するセメント粉の配合割合を高くすることで、炭材内装粒子の圧潰強度は向上する。図６に示すように、セメント粉の配合割合を１質量％以上にすれば４週間後の圧潰強度は２５Ｎ／個となる。図５に示すように、３日後強度は、４週間後強度×０．４程度となるので、９．８Ｎ／個の圧潰強度は３日後に得られることがわかる。 FIG. 6 is a graph showing the relationship between the blending ratio of cement powder and the crushing strength of carbonaceous material interior particles. In FIG. 6, the horizontal axis is the mixing ratio (mass%) of the cement powder to the mixed powder, and the vertical axis is the crushing strength (N / piece) of the carbonaceous material interior particles after cement curing for 4 weeks. As shown in FIG. 6, the crushing strength of the carbonaceous material interior particles is improved by increasing the mixing ratio of the cement powder to the mixed powder. As shown in FIG. 6, if the blending ratio of the cement powder is 1% by mass or more, the crushing strength after 4 weeks becomes 25 N / piece. As shown in FIG. 5, since the strength after 3 days is about the strength after 4 weeks × 0.4, it can be seen that the crushing strength of 9.8 N / piece is obtained after 3 days.

次に、セメント粉の配合割合を０〜１２質量％に変えて製造した炭材内装粒子を含む焼結原料を用いて炭材内装焼結鉱を製造し、各炭材内装焼結鉱の中から炭材内装粒子に由来する部分を抜き出した。炭材内装焼結鉱の中の炭材内装粒子に由来する部分の気孔率をＪＩＳ Ｒ １６５５：２００３に規定される方法で測定した。各炭材内装焼結鉱の中の炭材内装粒子に由来する部分の気孔率の測定結果を図７に示す。 Next, a sinter material containing carbonaceous material interior particles produced by changing the mixing ratio of cement powder to 0 to 12% by mass is used to produce a sinter material inside the material material, and the sinter is contained in each material material interior. The part derived from the carbonaceous material interior particles was extracted from. The porosity of the portion derived from the carbonaceous interior particles in the carbonaceous interior sintered ore was measured by the method specified in JIS R 1655: 2003. FIG. 7 shows the measurement results of the porosity of the portion derived from the carbon material interior particles in each coal material interior sintered ore.

図７は、セメント粉の配合割合と炭材内装焼結鉱の中の炭材内装粒子に由来する部分の気孔率との関係を示すグラフである。図７において、横軸は混合粉に対するセメント粉の配合割合（質量％）であり、縦軸は炭材内装焼結鉱の中の炭材内装粒子に由来する部分の気孔率（％）である。図７に示すように、混合粉に対するセメント粉の配合割合を高くすると、炭材内装焼結鉱の中の炭材内装粒子に由来する部分の気孔率は低下する。炭材内装焼結鉱の中の炭材内装粒子に由来する部分の気孔率が高い方が高炉における還元反応性に有利となる。さらに、セメント粉の配合割合を高くすると、高炉原料におけるスラグ分が増えることになり好ましくない。このため、セメント粉の配合割合はなるべく低いことが好ましく、これらのことから、セメント粉の配合割合を１０質量％以下とすることが好ましく、６質量％以下とすることがより好ましい。 FIG. 7 is a graph showing the relationship between the mixing ratio of cement powder and the porosity of the portion derived from the carbon material interior particles in the carbon material interior sintered ore. In FIG. 7, the horizontal axis is the mixing ratio (mass%) of the cement powder to the mixed powder, and the vertical axis is the porosity (%) of the portion derived from the carbon material interior particles in the carbon material interior sintered ore. .. As shown in FIG. 7, when the mixing ratio of the cement powder to the mixed powder is increased, the porosity of the portion derived from the carbon material interior particles in the carbon material interior sintered ore decreases. The higher the porosity of the portion derived from the coal material interior particles in the coal material interior sintered ore, the more advantageous the reduction reactivity in the blast furnace. Further, increasing the mixing ratio of the cement powder is not preferable because the slag content in the blast furnace raw material increases. Therefore, the blending ratio of the cement powder is preferably as low as possible, and from these facts, the blending ratio of the cement powder is preferably 10% by mass or less, and more preferably 6% by mass or less.

混合粉に対するセメント粉の配合割合を高めることで炭材内装粒子の圧潰強度を高めることができる。しかしながら、セメント粉の配合割合を高め過ぎると、炭材内装粒子のスラグ成分が増加する。さらに、セメント粉の配合割合を高め過ぎると、セメント粉と水との水和反応で生成する析出物が炭材内装粒子内の気孔を閉塞し、炭材内装粒子の気孔率が低下する。このスラグ成分の増加抑制と、一定以上の気孔率を確保するために、混合粉に対するセメント粉の配合割合は、１質量％以上１０質量％以下であることが好ましく、１質量％以上６質量％以下であることがより好ましい。 By increasing the mixing ratio of cement powder to the mixed powder, the crushing strength of the carbonaceous material interior particles can be increased. However, if the blending ratio of the cement powder is too high, the slag component of the carbonaceous material interior particles increases. Further, if the mixing ratio of the cement powder is too high, the precipitate formed by the hydration reaction between the cement powder and water closes the pores in the carbonaceous material interior particles, and the porosity of the carbonaceous material interior particles decreases. In order to suppress the increase of the slag component and secure a porosity of a certain level or more, the mixing ratio of the cement powder to the mixed powder is preferably 1% by mass or more and 10% by mass or less, and 1% by mass or more and 6% by mass or more. It is more preferable that it is as follows.

以上、説明したように、本実施形態に係る炭材内装粒子の製造方法を実施することで、圧潰強度の高い炭材内装粒子を安価に製造できるとともに、焼結機へ搬送され、焼結機に装入される工程において、崩壊する炭材内装粒子を少なくできる。そして、当該炭材内装粒子を含む焼結原料を焼結して炭材内装焼結鉱を製造することで、焼結鉱に還元されやすい焼結鉱組織が多く形成され、炭材内装焼結鉱の還元効率の向上が実現できる。 As described above, by implementing the method for producing the carbonaceous material interior particles according to the present embodiment, the carbonaceous material interior particles having high crushing strength can be produced at low cost, and the particles are transported to the sintering machine and are conveyed to the sintering machine. It is possible to reduce the amount of carbonaceous material interior particles that disintegrate in the process of being charged into the material. Then, by sintering the sintering raw material containing the sinter interior particles to produce the sinter interior sinter, many sinter structures that are easily reduced to the sinter are formed, and the sinter inside the sinter Improvement of ore reduction efficiency can be realized.

また、Ｂｌａｉｎｅ比表面積が１８００ｃｍ２／ｇ未満または粒径４５μｍ以下となる鉄鉱石粉の含有割合が８０質量％未満の鉄鉱石粉を用いた場合であっても、混合粉に対するセメント粉の配合割合が１質量％以上１０質量％以下となるようにセメント粉を配合することで、焼結機へ直送できる強度の高い炭材内装粒子を製造できることが確認された。 Further, even when iron ore powder having a specific surface area of less than 1800 cm 2 / g or a particle size of 45 μm or less and an iron ore powder having a content of less than 80% by mass is used, the mixing ratio of cement powder to the mixed powder is 1. It was confirmed that by blending the cement powder so as to have a mass% or more and 10% by mass or less, it is possible to produce high-strength carbonaceous material interior particles that can be directly sent to the sintering machine.

次に炭材内装粒子を含む焼結原料を焼結して製造された炭材内装焼結鉱の還元反応性を確認した結果を説明する。図８は、実施例および比較例の焼結鉱のＲＩを示すグラフである。ＲＩは、焼結鉱の被還元性を示す指標であって、ＪＩＳ Ｍ ８７１３に準拠して測定される値である。 Next, the result of confirming the reduction reactivity of the sinter for the interior of the carbonaceous material produced by sintering the sintering raw material containing the inner particles of the carbonaceous material will be described. FIG. 8 is a graph showing RI of sinters of Examples and Comparative Examples. RI is an index showing the reducibility of the sinter, and is a value measured in accordance with JIS M 8713.

図８に示した比較例では、セメント粉が配合されず、焼結機へ搬送、装入される工程で炭材内装粒子が崩壊したことを模擬し、炭材内装粒子を含まない焼結原料を６５０ｔ／ｈの投入速度で焼結機へ投入して焼結鉱を製造した。一方、実施例では、セメント粉が配合され、焼結機へ搬送、装入される工程で炭材内装粒子が崩壊しないとして、炭材内装粒子を内数で約７質量％（約５０ｔ／ｈ相当）配合した焼結原料を６５０ｔ／ｈの投入速度で焼結機へ投入して焼結鉱を製造した。 In the comparative example shown in FIG. 8, it is simulated that the carbonaceous material interior particles collapsed in the process of transporting and charging the cement powder into the sintering machine without blending the cement powder, and the sintering raw material does not contain the carbonaceous material internal particles. Was charged into the sinter at a charging rate of 650 t / h to produce sinter. On the other hand, in the embodiment, assuming that the carbonaceous material interior particles do not collapse in the process of blending the cement powder, transporting the cement powder to the sintering machine, and charging the material, about 7% by mass (about 50 t / h) of the carbonaceous material interior particles are included. (Equivalent) The blended sintering raw material was charged into a sinter at a charging rate of 650 t / h to produce a sinter.

図８に示すように、実施例の炭材内装焼結鉱のＲＩは、比較例の焼結鉱のＲＩより３％高くなることが確認された。この結果から、本実施形態に係る炭材内装粒子の製造方法を用いて圧潰強度の高い炭材内装粒子を製造することで、焼結機へ搬送、装入される工程で崩壊する炭材内装粒子を少なくでき、これにより、当該炭材内装粒子を含む焼結原料から製造される炭材内装焼結鉱の被還元性を向上できることがわかる。 As shown in FIG. 8, it was confirmed that the RI of the carbonaceous interior sinter of the example was 3% higher than the RI of the sinter of the comparative example. From this result, by producing the carbonaceous material interior particles having high crushing strength by using the method for producing the carbonaceous material interior particles according to the present embodiment, the carbon material interior that collapses in the process of being transported to the sintering machine and charged. It can be seen that the number of particles can be reduced, and as a result, the reducibility of the sinter for the sinter produced from the sinter raw material containing the sinter for the sinter can be improved.

１０ 炭材内装粒子の製造工程
１２ 鉄鉱石粉
１４ 貯蔵槽
１６ 生石灰
１８ 貯蔵槽
２０ セメント粉
２２ 貯蔵槽
２４ 搬送機
２６ 水
２８ 混練機
３０ 混合粉
３２ コークス粒子
３４ 貯蔵槽
３６ 搬送機
３８ 造粒機
４０ 炭材内装粒子
５０ 原料
５２ 造粒機
６０ 下方吸引式焼結機
７０ 高炉
１００ 炭材内装焼結鉱の製造工程 10 Manufacturing process of carbonaceous material interior particles 12 Iron ore powder 14 Storage tank 16 Fresh lime 18 Storage tank 20 Cement powder 22 Storage tank 24 Conveyor 26 Water 28 Kneader 30 Mixing powder 32 Coke particles 34 Storage tank 36 Conveyor 38 Granulation machine 40 Coal material interior particles 50 Raw material 52 Granulation machine 60 Downward suction type sintering machine 70 Blast furnace 100 Coal material interior sintered ore manufacturing process

Claims (2)

粉状の鉄含有原料と、石灰含有原料と、セメント粉と、を混合して混合粉とし、
前記混合粉と、粒径が８ｍｍ以下の炭材とを造粒して、炭材核の周囲に前記混合粉からなる外層が形成された炭材内装粒子を製造する、炭材内装粒子の製造方法であって、
前記混合粉に対するセメント粉の配合割合が１質量％以上６質量％以下になるように前記セメント粉を配合する、炭材内装粒子の製造方法。 The powdered iron-containing raw material, the lime-containing raw material, and the cement powder are mixed to form a mixed powder.
Production of carbonaceous material interior particles by granulating the mixed powder and a carbonaceous material having a particle size of 8 mm or less to produce carbonaceous material interior particles in which an outer layer composed of the mixed powder is formed around a carbon material core. It ’s a method ,
A method for producing charcoal interior particles, wherein the cement powder is blended so that the blending ratio of the cement powder to the mixed powder is 1% by mass or more and 6% by mass or less. 請求項１に記載の炭材内装粒子の製造方法で製造された炭材内装粒子を、鉄含有原料と、副原料と、凝結材と、を混合、造粒した造粒粒子に配合して焼結原料とし、
前記焼結原料を焼結機のパレットに装入して焼結する、炭材内装焼結鉱の製造方法。 The carbonaceous material interior particles produced by the method for producing carbonaceous material interior particles according to claim 1 are mixed with an iron-containing raw material, an auxiliary raw material, and a coagulant, and mixed with the granulated granulated particles and fired. As a raw material
A method for producing a carbonaceous interior sinter, in which the sintering raw material is charged into a pallet of a sintering machine and sintered.
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