JP5987958B2 - Method of adding binder to sintering raw material - Google Patents

Method of adding binder to sintering raw material Download PDF

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JP5987958B2
JP5987958B2 JP2015152039A JP2015152039A JP5987958B2 JP 5987958 B2 JP5987958 B2 JP 5987958B2 JP 2015152039 A JP2015152039 A JP 2015152039A JP 2015152039 A JP2015152039 A JP 2015152039A JP 5987958 B2 JP5987958 B2 JP 5987958B2
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sintering
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健一 八ヶ代
健一 八ヶ代
淳治 長田
淳治 長田
大山 浩一
浩一 大山
茂 樫村
茂 樫村
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Nippon Steel Corp
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Description

本発明は、鉄鋼製造用原料の一つである焼結鉱を製造するにあたり、その原料となる焼結原料を造粒する際の焼結原料へのバインダーの添加方法に関する。   The present invention relates to a method of adding a binder to a sintered raw material when granulating a sintered raw material that is a raw material for producing a sintered ore which is one of raw materials for steel production.

焼結原料は鉄鉱石からなる粉鉱石であり、必要に応じて成分調整する副原料や凝結材を配合し、焼成前に、この粉鉱石に水とバインダーを混合し造粒処理することで、焼結機へ装入する微粉量を低減している。この造粒は、焼結生産性の維持改善に重要な操作であり、従来から各種の造粒技術が提案されてきた。
例えば、特許文献1には、生石灰粉に予め水を加えてなる生石灰スラリーを、ミキサーの上流側に配置された搬送ベルトに流し込み、この生石灰スラリー上に含鉄粉を切り出し積層して搬送し、これらを混合装置と造粒装置に順次供給して、擬似粒子を製造することで、細粒からの核の形成を促進して、造粒性を向上させ得ることが開示されている。
また、特許文献2には、ミキサーにおいて3分間以上、混合、造粒した焼結原料に、生石灰や消石灰などのバインダーを添加し、更に混合、造粒することで、造粒性を向上できることが開示されている。
Sintering raw material is powdered ore made of iron ore, blending auxiliary materials and coagulants to adjust the ingredients as necessary, and mixing and granulating this powdered ore with water and binder before firing, The amount of fine powder charged into the sintering machine is reduced. This granulation is an important operation for maintaining and improving sintering productivity, and various granulation techniques have been proposed.
For example, in Patent Document 1, a quick lime slurry obtained by adding water to quick lime powder in advance is poured into a conveyor belt disposed on the upstream side of the mixer, and iron-containing powder is cut and laminated on the quick lime slurry and conveyed. Is sequentially supplied to a mixing device and a granulating device to produce pseudo particles, thereby promoting the formation of nuclei from fine particles and improving the granulating property.
Further, in Patent Document 2, the granulating property can be improved by adding a binder such as quick lime or slaked lime to a sintered raw material mixed and granulated in a mixer for 3 minutes or more, and further mixing and granulating. It is disclosed.

特開平4−254533号公報JP-A-4-254533 特開昭57−200530号公報Japanese Laid-Open Patent Publication No. 57-200530

しかしながら、前記従来の方法には、未だ解決すべき以下のような問題があった。
特許文献1の方法では、生石灰スラリーをミキサーの上流側に配置された搬送ベルトに流し込むため、水和反応によって生成した消石灰(Ca(OH))が多量に含まれる粘着性の高いスラリー上に、含鉄粉を切り出して積層することになる。このため、生石灰スラリー中の消石灰が凝集し(ダマとなり)、これを含鉄粉に均一に分散させることができず、造粒過程で、擬似粒子中に消石灰の濃淡が発生する。その結果、造粒性が低下して未造粒の微粉が増加するため、生石灰の使用量を増加させる必要があり、コストの上昇を招く。
また、特許文献2の方法では、生石灰や消石灰の全量をミキサー内に投入するため、生石灰が消化する時間や、消石灰が水に溶解し分散する時間を、十分に確保できず、生石灰や消石灰の効果を十分に発揮できずに、未造粒の微粉が残存することになる。
特に、近年、劣質な鉄鉱石を粉砕処理し浮遊選鉱処理して得られる難造粒性の粉鉱石(即ち、微粉原料)が増加してきており、この微粉原料を、上記した従来の方法で造粒処理しようとすると、造粒性が著しく低下してしまう。
However, the conventional method still has the following problems to be solved.
In the method of Patent Document 1, quick lime slurry is poured into a conveyor belt arranged on the upstream side of the mixer, and therefore, on a highly sticky slurry containing a large amount of slaked lime (Ca (OH) 2 ) generated by a hydration reaction. The iron-containing powder is cut out and laminated. For this reason, the slaked lime in the quicklime slurry aggregates (becomes lumps) and cannot be uniformly dispersed in the iron-containing powder, and the density of the slaked lime is generated in the pseudo particles during the granulation process. As a result, the granulation property is reduced and the amount of ungranulated fine powder is increased. Therefore, it is necessary to increase the use amount of quick lime, which causes an increase in cost.
In addition, in the method of Patent Document 2, since the entire amount of quicklime and slaked lime is charged into the mixer, the time for quicklime to digest and the time for slaked lime to dissolve and disperse in water cannot be secured sufficiently. The effect cannot be sufficiently exhibited, and ungranulated fine powder remains.
In particular, in recent years, the number of difficult-to-granulate powder ores obtained by crushing inferior iron ore and flotation processing (that is, fine powder raw materials) has increased, and this fine powder raw material is produced by the conventional method described above. When trying to process the granule, the granulation property is remarkably lowered.

本発明はかかる事情に鑑みてなされたもので、生石灰や消石灰のバインダーの使用量を増加させることなく、造粒性を効率的に改善して、難造粒性を有する微粉原料を使用可能にする焼結原料へのバインダーの添加方法を提供することを目的とする。   The present invention has been made in view of such circumstances, and without increasing the amount of quicklime or slaked lime binder used, it is possible to efficiently improve granulation and to use a fine powder material having difficult granulation. An object of the present invention is to provide a method for adding a binder to a sintered raw material.

前記目的に沿う本発明に係る焼結原料へのバインダーの添加方法は、鉄鉱石として、500μmアンダーが50質量%以上かつ10μmアンダーが5質量%以下の粒度の粉鉱石である微粉原料を用いる焼結原料に、生石灰及び消石灰のいずれか1又は2からなるバインダーを、生石灰換算で前記焼結原料の全量の外掛けで0.5質量%以上6質量%以下の量加え、撹拌機で撹拌して造粒機で造粒するに際し、少なくとも前記撹拌機内及び該撹拌機の上流側に配置された原料搬送コンベア上で、前記バインダーを前記焼結原料に添加する(但し、前記原料搬送コンベア上で前記バインダーを前記焼結原料へ添加する方法のうち、前記バインダーを搬送用の空気又は水に混合して吹き付ける方法、及びフィーダから落下している前記バインダーに空気又は水を吹き付ける方法を除く)。   The method of adding the binder to the sintered raw material according to the present invention in accordance with the above-described object is to use a fine raw material that is a fine ore having a particle size of 500 μm under 50 μm or more and 10 μm under 5% by weight as iron ore. A binder composed of quick lime and slaked lime is added to the ligation raw material in an amount of 0.5% by mass or more and 6% by mass or less as an outer shell of the total amount of the sintered raw material in terms of quick lime, and stirred with a stirrer When granulating with a granulator, the binder is added to the sintered raw material at least on the raw material conveyor arranged in the agitator and upstream of the agitator (however, on the raw material conveyor) Among the methods of adding the binder to the sintering raw material, the binder is mixed with air or water for transport and sprayed, and the binder falling from the feeder is empty. Excluding methods of spraying water or water).

本発明に係る焼結原料へのバインダーの添加方法において、前記撹拌機の撹拌羽根の周速を2m/秒以上にすることが、本発明の効果がより顕著になる観点から好ましい。   In the method for adding the binder to the sintered raw material according to the present invention, it is preferable that the peripheral speed of the stirring blade of the stirrer is 2 m / second or more from the viewpoint of more remarkable effects of the present invention.

本発明に係る焼結原料へのバインダーの添加方法は、鉄鉱石として微粉原料を使用する焼結原料に、生石灰や消石灰のバインダーを所定量加えるに際し、原料搬送コンベア上のみならず、更に撹拌機内に、バインダーをそれぞれ添加する分割添加を行う。このように、原料搬送コンベア上にバインダーを添加することで、生石灰の消化や消石灰の溶解分散が促進されて、良好な造粒物が得られることに加え、撹拌機内にバインダーを添加することで、機械的な分散効果が発揮されて、残存微粉を低減できる。
従って、従来のように、撹拌機内のみ、又は原料搬送コンベア上のみに(即ち、一箇所に)、バインダーの全量を添加する場合と同じバインダー量で、焼結生産性を改善できるため、生石灰や消石灰のバインダーの使用量を増加させることなく、造粒性を効率的に改善して、難造粒性を有する微粉原料を使用できる。
The method for adding the binder to the sintered raw material according to the present invention is not only on the raw material conveyor but also in the stirrer when adding a predetermined amount of quick lime or slaked lime binder to the sintered raw material using the fine powder raw material as iron ore. In addition, divided addition for adding the binder is performed. Thus, by adding a binder on a raw material conveyance conveyor, digestion of quick lime and dissolution / dispersion of slaked lime are promoted, and in addition to obtaining a good granulated product, a binder is added in the stirrer. The mechanical dispersion effect is exhibited and the residual fine powder can be reduced.
Therefore, since the sintering productivity can be improved with the same binder amount as when the total amount of the binder is added only in the stirrer or on the raw material transport conveyor (that is, in one place) as in the prior art, quick lime and Without increasing the amount of slaked lime binder used, it is possible to efficiently improve the granulation property and use a fine powder material having difficult granulation property.

また、撹拌機の撹拌羽根の周速を2m/秒以上にする場合、生石灰や消石灰を、焼結原料全体に更に分散させる効果が促進され、焼結生産性を一層向上させることができる。   Moreover, when making the peripheral speed of the stirring blade of a stirrer 2 m / sec or more, the effect which further disperses quick lime and slaked lime in the whole sintering raw material is accelerated | stimulated, and sintering productivity can be improved further.

添加するバインダーの種類が造粒物の造粒性に及ぼす影響を示すグラフである。It is a graph which shows the influence which the kind of binder to add has on the granulation property of a granulated material. 撹拌羽根の周速を1m/秒とした場合の生石灰の添加量と撹拌機内の添加割合が焼結生産性の向上率に及ぼす影響を示す説明図である。It is explanatory drawing which shows the influence which the addition amount of a quicklime and the addition ratio in a stirrer have on the improvement rate of sintering productivity when the peripheral speed of a stirring blade is 1 m / sec. 撹拌羽根の周速を2m/秒とした場合の生石灰の添加量と撹拌機内の添加割合が焼結生産性の向上率に及ぼす影響を示す説明図である。It is explanatory drawing which shows the influence which the addition amount of a quicklime and the addition ratio in a stirrer have on the improvement rate of sintering productivity when the peripheral speed of a stirring blade is 2 m / sec.

続いて、添付した図面を参照しつつ、本発明を具体化した実施の形態につき説明し、本発明の理解に供する。
まず、本発明に想到した経緯について説明する。
はじめに、粉鉱石(鉄鉱石)のうち、難造粒性を示す微粉原料の造粒性について説明する。
本発明が造粒の対象とする焼結原料は、篩目10μmアンダーの粒子(微粒子)が5質量%以下と極めて少なく、500μmアンダーの粒子が50質量%以上と非常に多い、難造粒性を示す微粉原料(鉄鉱石)である。この微粉原料が、通常の鉄鉱石と異なる点は、10μmアンダーの粒子が極めて少ない点であり、例えば、鉄鉱石の粉砕処理と水による比重選鉱処理を繰り返すことで、この特徴が得られることがわかった。なお、500μmアンダーの粒子の質量%の測定に際しては、微粉原料(2kg)を、150℃で1時間乾燥した後、0.5mmの篩目(JIS Z8801−1「試験用ふるい−第1部:金属製網ふるい」に拠る)で分級し、篩下の質量%を求めた。また、10μmアンダーの微粒子の質量%の測定に際しては、上記乾燥後の微粉原料を対象に、レーザー回折散乱法の測定機器(日機装株式会社製 MICROTRAC(登録商標) MT3300型、測定範囲:0.02〜1400μm)を用いた。
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
First, the background to the present invention will be described.
First, the granulation property of the fine powder raw material which shows difficult granulation property among powder ores (iron ore) is demonstrated.
The sintering raw material to be granulated according to the present invention has extremely small particles (fine particles) with a mesh size of 10 μm or less as 5% by mass or less, and very few particles with 500 μm or less as 50% by mass or more. Is a fine powder raw material (iron ore). This fine powder raw material is different from ordinary iron ore in that the number of particles under 10 μm is extremely small. For example, this feature can be obtained by repeating iron ore crushing treatment and specific gravity beneficiation treatment with water. all right. In the measurement of the mass% of particles having a size of 500 μm or less, a fine powder material (2 kg) was dried at 150 ° C. for 1 hour, and then a 0.5 mm sieve mesh (JIS Z8801-1 “Test sieve—Part 1: (Based on “metal mesh sieve”), and the mass% under the sieve was determined. Further, when measuring the mass% of fine particles under 10 μm, the measurement device of the laser diffraction scattering method (MICROTRAC (registered trademark) MT3300, manufactured by Nikkiso Co., Ltd., measurement range: 0.02) is used for the fine powder raw material after drying. ˜1400 μm) was used.

ここで、鉄鉱石として少なくとも1種又は複数種の粉鉱石(微粉原料の場合を含む)を含むものが焼結原料であり、この焼結原料に、副原料(成分調整用原料)や凝結材(例えば、コークス粉や石炭粉等)が含まれるか否かは任意であり、本実施の形態での焼結原料とは、生石灰と消石灰(バインダー)を含まないものをさす。なお、焼結原料に副原料や凝結材が含まれる場合、焼結原料中の副原料と凝結材の合計量が質量比で30質量%以下程度(焼結原料中の鉄鉱石量:例えば、焼結原料の70〜100質量%程度)となるように、鉄鉱石に副原料と凝結材を添加する場合があるが、焼結原料の造粒性や造粒物の強度は、これらの添加量では改善しにくい。   Here, the iron ore containing at least one or more kinds of fine ores (including fine powder raw materials) is a sintered raw material, and the auxiliary raw materials (component adjusting raw materials) and coagulants are included in this sintered raw material. Whether or not (for example, coke powder or coal powder) is included is arbitrary, and the sintering raw material in the present embodiment refers to a material that does not include quick lime and slaked lime (binder). In addition, when the auxiliary material and the coagulant are included in the sintered raw material, the total amount of the auxiliary material and the coagulant in the sintered material is about 30% by mass or less (the amount of iron ore in the sintered material: The auxiliary raw material and the coagulant may be added to the iron ore so as to be about 70 to 100% by mass of the sintered raw material). It is difficult to improve by the amount.

上記した粒度構成、即ち10μmオーバーかつ500μmアンダー程度に概ね揃った微粉原料を造粒すると、隣接する原料粒子の間に空間が形成される。
しかし、上記したように、微粉原料中には、この空間を充填する10μmアンダーの微粒子が極めて少ないため、微粉原料は空間を内包したまま造粒され、造粒物の強度が極めて低くなる。このため、例えセルロース等の粘着質のバインダーを用いて微粉原料を造粒し、隣接する微粉原料の粒子同士を粘着できたとしても、造粒物内部には空間が残留するため、造粒物の強度を向上しにくい。
更に一般に、粉鉱石は水を用いて造粒するが、結晶水を4質量%以上含む高結晶水鉱石を、微粉原料に30質量%以上60質量%以下含む場合、高結晶水鉱石の気孔に水が吸収され、造粒物強度が経時劣化(低下)する問題もある。
上記状況において、上記した微粉原料の造粒に用いるバインダーには、10μmアンダーの微粒子を供給でき、上記した空間を充填できるものが好ましいことに想到した。
When the above-mentioned particle size configuration, that is, a fine raw material that is roughly aligned to about 10 μm and under 500 μm is granulated, a space is formed between adjacent raw material particles.
However, as described above, since the fine powder raw material has very few 10 μm-undersized fine particles filling the space, the fine powder raw material is granulated while enclosing the space, and the strength of the granulated product becomes extremely low. For this reason, even if the fine powder raw material is granulated using an adhesive binder such as cellulose, and even if the particles of the adjacent fine powder raw material can be adhered to each other, a space remains in the granulated product. Hard to improve strength.
More generally, the powdered ore is granulated using water. However, when the high-crystal water ore containing 4% by mass or more of crystal water is contained in the fine powder raw material by 30 to 60% by mass, the pores of the high-crystal water ore There is also a problem that water is absorbed and the strength of the granulated material deteriorates (decreases) with time.
In the above situation, it was conceived that the binder used for the granulation of the fine powder raw material is preferably one that can supply fine particles of under 10 μm and can fill the space described above.

なお、固形バインダーには、ベントナイトや炭酸カルシウム等があるが、通常の混練(撹拌)処理程度では、上記した微粉原料へ固形バインダーを均一分散させるのが難しいことが判明した。
これは、上記したように、微粉原料の粒径が10μmオーバーかつ500μmアンダー程度の大きさに概ね揃っており、一般には広範囲な粒度分布を持つことで撹拌(混練)による原料の混合が進むため、粒子が微粒化せず溶解もしないベントナイトや炭酸カルシウム等を添加しても分散が進まないものと考えられ、この観点からも、別の手段で10μmアンダーの微粒子を添加することが好ましいと考えられた。
以上のことから、本発明者らは、鉄鉱石として、500μmアンダーが50質量%以上かつ10μmアンダーが5質量%以下の粒度である微粉原料を用いた焼結原料を造粒するに際し、撹拌(混練)や造粒を容易化するバインダーとして、生石灰と消石灰に想到した。なお、焼結パレットに入れる焼結原料は撹拌を行わない場合もある。
In addition, although there exist bentonite, calcium carbonate, etc. in a solid binder, it turned out that it is difficult to disperse | distribute a solid binder uniformly to the above-mentioned fine powder raw material by the grade of a normal kneading | mixing (stirring) process.
This is because, as described above, the particle size of the fine powder raw material is almost uniform in the size of about 10 μm over and under 500 μm, and generally the mixing of the raw material by stirring (kneading) progresses due to the wide particle size distribution. It is considered that dispersion does not proceed even when bentonite, calcium carbonate, or the like, in which the particles are not atomized and dissolved, is added, and from this viewpoint, it is preferable to add fine particles under 10 μm by another means. It was.
From the above, the present inventors agitated (granulated) a sintered raw material using a fine raw material having a particle size of 500 μm under 50 mass% and 10 μm under 5 mass% as iron ore. As a binder for facilitating kneading and granulation, the inventors came up with quick lime and slaked lime. In addition, the sintering raw material put into a sintering pallet may not be stirred.

次に、生石灰と消石灰による造粒メカニズムについて説明する。
生石灰は、混練や造粒中に水と接触することで一部が吸湿し消化(消石灰化)して微粒化し、水と共に微粉原料に均一に混ざり易くなるものであると考えられる。なお、生石灰としては、CaOが例えば84質量%以上のものが多用されている。
ここで、生成した消石灰の一部については、水に溶解することでも、微粉原料に均一に混ざり易くなる。
なお、微粉原料に、生石灰の代わりに、又は生石灰と共に、消石灰を添加する場合も同様であり、一部の消石灰が水に溶解して、微粉原料中に均一に混ざり易くなる。
Next, the granulation mechanism by quicklime and slaked lime will be described.
It is considered that quick lime is partly absorbed by digestion (slaked calcification) and atomized by contact with water during kneading and granulation, and easily mixed with the fine powder raw material together with water. In addition, as quicklime, that whose CaO is 84 mass% or more is used abundantly.
Here, a part of the generated slaked lime is easily mixed with the fine powder raw material even by dissolving in water.
In addition, it is the same also when adding slaked lime to a fine powder raw material instead of quick lime or with quick lime, and a part of slaked lime melt | dissolves in water, and it becomes easy to mix uniformly in a fine powder raw material.

生石灰の消化で生成する消石灰や、水の蒸発等によって再晶出する消石灰は、粒径が10μmアンダーの微粒子であり、更にはサブミクロンオーダーの微粒子も多く含まれており、固体架橋によって上記微粉原料の造粒性向上や造粒物の強度向上に大きく寄与する。
従って、極力多くの生石灰を消化させること、生成する消石灰の粒径を小さくすること、極力多くの消石灰を造粒水に溶解すること、等で、造粒に寄与する消石灰を多量に生成させて、生成する消石灰を微粉原料全体に分散させ(マクロに分散させ)、各微粉原料の粒子表面に極力付着させる(ミクロに分散させる)こと、が重要となる。
Slaked lime produced by digestion of quick lime and slaked lime recrystallized by evaporation of water, etc. are fine particles with a particle size of under 10 μm, and also contain many fine particles of submicron order. This greatly contributes to the improvement of the granulation properties of the raw materials and the strength of the granules.
Therefore, a large amount of slaked lime that contributes to granulation can be generated by digesting as much quick lime as possible, reducing the particle size of slaked lime generated, dissolving as much slaked lime as possible in granulated water, etc. It is important to disperse the slaked lime to be produced throughout the fine powder raw material (macro dispersion) and to adhere as much as possible to the particle surface of each fine powder raw material (disperse into the micro).

なお、炭酸カルシウム(分子式:CaCO)は、生石灰や消石灰と同様にCaOを含み、そのCaO含有率が56質量%程度のものであり、石灰石あるいは単に石灰と称される場合がある。しかし、炭酸カルシウムは、化学的に安定な物質であって、吸湿による消化や水への溶解は起こりにくい。
従って、上記した生石灰や消石灰に、炭酸カルシウムは含まれない。
ここで、添加するバインダーの種類が造粒物の造粒性に及ぼす影響について、図1を参照しながら説明する。
In addition, calcium carbonate (molecular formula: CaCO 3 ) contains CaO similarly to quick lime and slaked lime, and has a CaO content of about 56% by mass, and may be referred to as limestone or simply lime. However, calcium carbonate is a chemically stable substance, and digestion due to moisture absorption and dissolution in water hardly occur.
Therefore, calcium carbonate is not contained in the above-mentioned quick lime and slaked lime.
Here, the influence which the kind of binder to add has on the granulation property of a granulated material is demonstrated, referring FIG.

なお、試験は、結晶水を4質量%以上含む高結晶水鉱石を0又は0を超え10質量%以下配合した500μmアンダーが50質量%以上かつ10μmアンダーが5質量%以下の粒度である難造粒性の微粉原料(焼結原料)に、バインダー(炭酸カルシウム、消石灰、生石灰)を外掛けで2質量%添加し、これを万能ミキサー(自転する撹拌羽根の軸を公転させる竪型ミキサー)で撹拌した後、ドラムミキサーで造粒処理した。ここでは、バインダー添加の評価基準として、バインダーを添加していない難造粒性の微粉原料(原料)のみのものについても、万能ミキサーで撹拌した後、ドラムミキサーで造粒処理した。
詳細条件は、水分:9〜12質量%の範囲で一定、撹拌:周速2.2m/秒、処理時間90秒、造粒:周速1.0m/秒、処理時間60秒、である。なお、周速は、万能ミキサー(撹拌機)とドラムミキサー(造粒機)において、回転するもの(羽根、ドラム等)で、一番速い部分の速度のことを意味する。
In addition, the test is a difficult structure in which 500 μm under which high crystal water ore containing 4% by weight or more of crystal water is blended with 0 or more than 0 and 10% by weight is 50 μm or more and 10 μm under is 5% by weight or less. Add 2% by mass of binder (calcium carbonate, slaked lime, quicklime) to the granular fine powder raw material (sintered raw material), and add it with a universal mixer (a vertical mixer that revolves the axis of the rotating stirring blade) After stirring, the mixture was granulated with a drum mixer. Here, as an evaluation standard for adding a binder, only a hardly granulated fine powder raw material (raw material) to which a binder was not added was stirred with a universal mixer and then granulated with a drum mixer.
Detailed conditions are: moisture: constant in the range of 9 to 12% by mass, stirring: peripheral speed 2.2 m / sec, treatment time 90 seconds, granulation: peripheral speed 1.0 m / sec, treatment time 60 seconds. The peripheral speed means the speed of the fastest part of a universal mixer (stirrer) and drum mixer (granulator) that rotate (blades, drums, etc.).

また、評価は、以下の手順で行った。
まず、上記した造粒処理した微粉原料(2kg)を、150℃で1時間乾燥した後、0.5mmの篩目(JIS Z8801−1「試験用ふるい−第1部:金属製網ふるい」に拠る)で分級し、0.5mmアンダーの割合を粉率と定義した。なお、粉率は、バインダーを添加していない微粉原料のみの粉率を「1.0」として、それぞれ算出した。
図1から、微粉原料に対して炭酸カルシウムを添加した場合、造粒性の改善が小さい(粉率:0.70)のに対し、微粉原料に対して生石灰又は消石灰を添加した場合は、造粒性が著しく改善(生石灰:0.41、消石灰:0.43)することを、本発明者らは初めて発見した。
これは、生石灰が水と接触することにより微粒化し、更に生成した消石灰(添加した消石灰)の一部が水に溶解することで、微粉原料に均一に混ざり易くなり、固体架橋によって微粉原料の造粒性向上や造粒物の強度向上に大きく寄与したためと考えられる。
Moreover, evaluation was performed in the following procedures.
First, the above granulated fine powder material (2 kg) was dried at 150 ° C. for 1 hour, and then passed through a 0.5 mm sieve mesh (JIS Z8801-1 “Test sieve—Part 1: Metal mesh sieve”). The ratio of 0.5 mm under was defined as the powder rate. The powder ratio was calculated by setting the powder ratio of only the fine powder raw material to which no binder was added to “1.0”.
From FIG. 1, when calcium carbonate is added to the fine powder raw material, the improvement in granulation is small (powder rate: 0.70), whereas when quick lime or slaked lime is added to the fine powder raw material, The present inventors have discovered for the first time that the graininess is remarkably improved (quick lime: 0.41, slaked lime: 0.43).
This is because quick lime is atomized by contact with water, and part of the generated slaked lime (added slaked lime) dissolves in water, making it easy to mix uniformly into the fine powder raw material. This is thought to be due to the great contribution to the improvement of graininess and the strength of the granulated product.

上記粉率は平均値であり、いずれのバインダーを用いた場合も、粉率値は5%程度のばらつきをもった。
一方、上記試験に用いた微粉原料として、結晶水を4質量%以上含む高結晶水鉱石を30〜60質量%配合したものを用いた場合、粉率が全体的に悪化(増加)し、特に、バインダーとして炭酸カルシウムを用いた場合は、概ね2〜3割程度のばらつきを示すのに対し、バインダーとして生石灰や消石灰を用いた場合は、炭酸カルシウムの粉率値のばらつきよりも小さな1割程度であった。これは、造粒時や造粒後に気孔に水が吸収され得る高結晶水鉱石を用いたとしても、バインダーとして炭酸カルシウムを用いると上記した固体架橋が安定せず、一方、生石灰や消石灰を用いると上記した固体架橋が安定するものと推定され、吸湿による消化や水への溶解が起きると、気孔への吸水が起こっても固体架橋が比較的安定しているものと推定された。
The powder ratio is an average value, and the powder ratio value varied by about 5% when any binder was used.
On the other hand, when the fine powder raw material used in the above test was blended with 30 to 60% by mass of high crystal water ore containing 4% by mass or more of crystal water, the powder rate was deteriorated (increased) as a whole. When calcium carbonate is used as a binder, it shows a variation of about 20 to 30%, whereas when quick lime or slaked lime is used as a binder, it is about 10% smaller than the variation of the powder rate value of calcium carbonate. Met. This is because even if a high crystal water ore that can absorb water into pores after granulation or after granulation is used, if calcium carbonate is used as a binder, the above-mentioned solid cross-linking is not stabilized, while quick lime or slaked lime is used. It was presumed that the above-mentioned solid cross-linking was stable. When digestion by moisture absorption or dissolution in water occurred, it was presumed that the solid cross-linking was relatively stable even if water absorption into the pores occurred.

以上のことから、本発明者らは、難造粒性を有する微粉原料の造粒性を向上できる焼結原料へのバインダーの添加方法に想到した。
即ち、鉄鉱石として、500μmアンダーが50質量%以上(更には60質量%以上)かつ10μmアンダーが5質量%以下(更には4質量%以下)の粒度の粉鉱石である微粉原料を用いた焼結原料(難造粒性微粉原料)に、生石灰及び消石灰のいずれか1又は2からなるバインダーを、生石灰換算で焼結原料の全量の外掛けで0.5質量%以上6質量%以下の量加え、撹拌機で撹拌して造粒機で造粒するに際し、少なくとも撹拌機内及び撹拌機の上流側に配置された原料搬送コンベア(以下、単にコンベアともいう)上で、バインダーを焼結原料に添加する。
From the above, the present inventors have come up with a method for adding a binder to a sintered raw material that can improve the granulating property of a fine powder raw material having difficult granulation properties.
That is, as iron ore, 500 μm under 50% by mass (further 60% by mass) and 10 μm under 5% by mass (further 4% by mass) fine powder raw material is used. An amount of 0.5% by mass or more and 6% by mass or less of a binder consisting of either quick lime or slaked lime as a raw material (refractory granulated fine powder raw material) as an outer shell of the total amount of the sintered raw material in terms of quick lime. In addition, when agitation is performed with a stirrer and granulation is performed with a granulator, the binder is used as a sintering raw material at least on a material conveying conveyor (hereinafter also simply referred to as a conveyor) disposed in the agitator and on the upstream side of the agitator. Added.

なお、焼結原料を、撹拌機を介さずに(撹拌を行うことなく)、コンベアから直接、造粒機に装入する場合は、造粒機内及び造粒機の上流側に配置された原料搬送コンベア(以下、単にコンベアともいう)上で、バインダーを焼結原料に添加する。
ここで、難造粒性微粉原料の粒度について、500μmアンダーの上限値を規定していないのは100質量%でもよく、また10μmアンダーの下限値を規定していないのは0質量%でもよいためである。
また、撹拌機には、前記した万能ミキサーの他に、従来公知のアイリッヒミキサー、レディゲミキサー、パドルミキサー等があり、混練機と呼ばれる場合もある。
以下、詳しく説明する。
In addition, when inserting a sintering raw material directly into a granulator directly from a conveyor, without going through a stirrer (without stirring), the raw material arrange | positioned in a granulator and the upstream of a granulator A binder is added to the sintering raw material on a transport conveyor (hereinafter also simply referred to as a conveyor).
Here, as for the particle size of the hardly granulated fine powder raw material, the upper limit value of 500 μm under may not be defined as 100% by mass, and the lower limit value of 10 μm under may not be defined as 0% by mass. It is.
In addition to the above-described universal mixer, the agitator includes conventionally known Eirich mixer, Redige mixer, paddle mixer, and the like, and is sometimes called a kneader.
This will be described in detail below.

本発明者らは、上記した焼結原料に、生石灰(バインダー)を添加し撹拌して造粒する工程において、生石灰の添加位置と、これを造粒した後、焼成した場合の焼結生産性の関係について、鋭意検討した。
生石灰の添加位置として、撹拌機の上流側に配置されたコンベア上には、他の原料と共に生石灰を載せる方法を採用し、撹拌機内には、生石灰のみを直接装入する方法を採用し、焼結原料として、結晶水を4質量%以上含む高結晶水鉱石を30〜60質量%配合した難造粒性微粉原料を用いた。なお、上記以外の試験条件は、図1に示した試験の詳細条件と略同一とした。
この結果を、図2に示す。なお、図2は、撹拌機の撹拌羽根の周速を1m/秒にした場合において、焼結原料に添加する生石灰を、コンベア上と撹拌機内の双方に分割添加した際に、この分割添加の割合が焼結生産性の向上率に及ぼす影響を示している。
In the process of adding quick lime (binder) to the above-mentioned sintered raw material and stirring and granulating, the inventors added the quick lime and the productivity of sintering when it is granulated and then fired. The relationship between the two was studied earnestly.
As a quick lime addition position, a method of placing quick lime together with other raw materials on a conveyor arranged on the upstream side of the stirrer is adopted, and a method in which only quick lime is directly charged in the stirrer is adopted. As the kneading raw material, a hardly granulated fine powder raw material containing 30 to 60% by mass of high crystal water ore containing 4% by mass or more of crystal water was used. The test conditions other than the above were substantially the same as the detailed conditions of the test shown in FIG.
The result is shown in FIG. 2 shows that when the peripheral speed of the stirring blade of the stirrer is 1 m / second, the quick lime added to the sintering raw material is added separately on both the conveyor and the stirrer. The influence of the ratio on the improvement rate of the sintering productivity is shown.

ここで、図2の縦軸は、生石灰を添加しない焼結原料の焼結生産性を「1」としたときの焼結生産性の向上割合を示している。なお、焼結生産性は、焼成速度と歩留の積で表され、焼成速度の単位は(kg/分)、歩留の単位は(質量%)、で表される。
また、図2の横軸は、焼結原料に添加する総生石灰量(生石灰の総量)のうち、撹拌機内へ直接添加した生石灰量の割合を示しており、撹拌機内の添加割合「0」は、添加する生石灰の全量をコンベア上に添加した場合を、また添加割合「1」は、添加する生石灰の全量を撹拌機内に添加した場合を、それぞれ意味している。
Here, the vertical axis of FIG. 2 shows the improvement rate of the sintering productivity when the sintering productivity of the sintering raw material to which quicklime is not added is “1”. The sintering productivity is represented by the product of the firing rate and the yield. The unit of the firing rate is (kg / min), and the unit of the yield is (mass%).
Moreover, the horizontal axis of FIG. 2 shows the ratio of the amount of quicklime added directly into the stirrer out of the total amount of quicklime added to the sintering raw material (total amount of quicklime). The addition ratio “0” in the stirrer is The case where the total amount of quicklime to be added is added on the conveyor, and the addition ratio “1” means the case where the total amount of quicklime to be added is added to the stirrer.

この試験は、焼結原料への生石灰の総添加量(生石灰をコンベアと撹拌機内にそれぞれ分割添加した場合はその合計量、以下同様)を、焼結原料の総量に外掛けで、0.5質量%から最大6質量%まで増加させた場合について検討した。
図2に示すように、焼結原料への生石灰の総添加量の増加に伴い、焼結生産性の向上率が、全体的に上昇する傾向にある(×印から○印へ)。このとき、添加する生石灰の全量を、撹拌機前のコンベア上のみへ、又は撹拌機内のみへ投入する場合に対し、同量の生石灰を、撹拌機前のコンベア上と撹拌機内の双方に分割して、コンベア上の焼結原料と撹拌機内の焼結原料へ添加することで、焼結生産性が向上する(改善する)傾向が確認された。
In this test, the total amount of quicklime added to the sintered raw material (the total amount when quicklime is added separately in the conveyor and the stirrer, the same applies hereinafter) is multiplied by the total amount of the raw material, 0.5 The case where it was increased from 6% by mass to 6% by mass was examined.
As shown in FIG. 2, as the total amount of quicklime added to the sintering raw material increases, the improvement rate of the sintering productivity tends to increase as a whole (from the x mark to the ◯ mark). At this time, the same amount of quicklime is divided into both the conveyor before the stirrer and the stirrer in contrast to the case where the entire amount of quicklime to be added is put only on the conveyor before the stirrer or only into the stirrer. Thus, it was confirmed that the addition of the sintered raw material on the conveyor and the sintered raw material in the agitator tends to improve (improve) the sintering productivity.

上記した現象の内容について、以下に説明する。
生石灰を撹拌機前のコンベア上に添加する場合、焼結原料と接触した生石灰が、焼結原料の水分を吸収して消化し、溶解するため、生石灰を焼結原料中に分散させる時間(例えば、0.5〜5分程度)が確保されるものの、生石灰はコンベア上の焼結原料上に単に載置されるのみであり、機械的な撹拌操作は行われないため、焼結原料と接触できる生石灰量に限界があり、添加量が一定量以上になると、消化や分散が進行しにくくなるためと考えられる。ここで、吸水した生石灰や消石灰が一旦凝集すると(ダマ状になると)、その後の撹拌機において機械的分散作用を与えたとしても、十分な分散確保が困難になるためと推定される。
The contents of the above phenomenon will be described below.
When adding quick lime on the conveyor in front of the agitator, the quick lime in contact with the sintered raw material absorbs and digests the water of the sintered raw material and dissolves it, so that the quick lime is dispersed in the sintered raw material (for example, However, quick lime is merely placed on the sintered raw material on the conveyor and no mechanical stirring operation is performed, so it contacts the sintered raw material. It is considered that there is a limit to the amount of quicklime that can be produced, and digestion and dispersion are difficult to proceed when the addition amount exceeds a certain amount. Here, it is presumed that once the absorbed quicklime and slaked lime have aggregated (when they become lumpy), it is difficult to ensure sufficient dispersion even if a mechanical dispersion action is applied in the subsequent stirrer.

また、生石灰を撹拌機内に直接添加した場合は、前述した消化や溶解時間が十分に確保されないため、その効果に限界があると考えられるが、一方で、生石灰や消石灰を焼結原料中に機械的に分散させることができることから、総添加量の制約は少ないと考えられる。
以上のことから、これらの複合効果として、焼結原料への生石灰の総添加量が少ない場合には、撹拌機前のコンベア上への生石灰の添加割合が多いときに、焼結生産性の改善効果が大きくなるが、生石灰の総添加量が増加すると共に、撹拌機内への生石灰の添加割合を次第(徐々)に増加させた方が、焼結生産性の改善効果が大きい傾向となることを見出した。上記の生石灰や消石灰の事前添加と直接添加の併用効果(分割投入効果)が、一般に水との濡れ性が悪く吸水による造粒の不安定さが指摘されている高結晶水鉱石(結晶水を4質量%以上含む高結晶水鉱石を30〜60質量%配合した難造粒性微粉原料)で見られたことから、高結晶水鉱石の配合量が低い(結晶水を4質量%以上含む高結晶水鉱石を0又は0を超え10質量%以下配合した)難造粒性微粉原料でも、同様の効果が得られるものと考えられる。
In addition, when quick lime is added directly to the stirrer, the digestion and dissolution time described above is not sufficiently secured, so it is considered that the effect is limited. On the other hand, quick lime and slaked lime are added to the sintering raw material. The total amount added is considered to be limited.
From the above, as a combined effect of these, when the total amount of quicklime added to the sintering raw material is small, when the addition ratio of quicklime on the conveyor before the stirrer is large, improvement in sintering productivity Although the effect increases, the total amount of quicklime increases, and the effect of improving the sintering productivity tends to be greater when the proportion of quicklime added to the stirrer is gradually (gradually) increased. I found it. High crystal water ore (the crystallization water is used in combination with the above-mentioned quick addition and direct addition of lime and slaked lime) Since it was found in a highly granulated fine powder raw material containing 30 to 60% by mass of high crystal water ore containing 4% by mass or more, the amount of high crystal water ore is low (high containing 4% by mass or more of crystal water) It is considered that the same effect can be obtained even with a hardly granulated fine powder raw material containing 0 or more than 0% by mass of crystal water ore.

即ち、本発明者らは、焼結生産性の改善効果を最大化する方法として、焼結原料へ添加する生石灰を、撹拌機前のコンベア上と撹拌機内の2箇所に分割投入する方法に想到したものである。このように、焼結生産性の改善効果は、生石灰の分割添加、例えば、撹拌機内(コンベア上)への生石灰の添加割合を0.1以上0.9以下にすることで得られるが、下限を0.2、上限を0.8とすることが好ましい。
また、この作用は、図2の試験結果からも明らかなように、生石灰の総添加量が、焼結原料の全量の外掛けで(焼結原料100質量%に対して)0.5質量%から6質量%までの範囲において確認されたことから、生石灰の分割添加を、生石灰の総添加量が焼結原料の全量の外掛けで0.5質量%以上6質量%以下の範囲において行うことを規定した。
That is, the present inventors conceived as a method of maximizing the effect of improving the sintering productivity, a method in which quick lime added to the sintering raw material is dividedly charged into two places on the conveyor before the stirrer and in the stirrer. It is a thing. Thus, the improvement effect of sintering productivity is obtained by dividing the addition of quicklime, for example, by making the addition ratio of quicklime into the stirrer (on the conveyor) 0.1 to 0.9, the lower limit Is preferably 0.2 and the upper limit is preferably 0.8.
Further, as is apparent from the test results of FIG. 2, this effect is such that the total amount of quicklime added is 0.5% by mass (based on 100% by mass of the sintered raw material) as a whole of the total amount of the sintered raw material. To 6 mass%, the quick addition of quicklime is performed in a range where the total amount of quicklime is 0.5 mass% or more and 6 mass% or less of the total amount of the sintered raw material. Stipulated.

なお、従来は、前記した特許文献1、2のように、コンベア上のみ又は撹拌機内のみに、生石灰の全量を添加していた。これは、造粒対象となる焼結原料が、篩目10μmアンダーの粒子(微粒子)を含む造粒性の良好な原料、即ち、易造粒性原料を含む焼結原料であることによる。
この易造粒性原料を含む焼結原料に生石灰を添加した場合、この焼結原料はもともと造粒性が良好であるため、生石灰の添加による焼結生産性の改善効果があまり現れない。このため、このような焼結原料に生石灰を分割添加したとしても、焼結生産性の向上率は、0.5〜1%の間で変動する程度で、添加割合の変動による影響があまり認められない。
従って、従来は、設備コストをかけてまで、コンベア上と撹拌機内の双方に、生石灰の添加装置を設置しなかった。しかし、本発明が造粒対象とする難造粒性微粉原料を含む(からなる)焼結原料では、コンベア上と撹拌機の双方に、生石灰の添加装置を設置することで、焼結生産性が向上し、設備コストに見合った効果が得られる。
In addition, conventionally, the total amount of quicklime was added only on a conveyor or only in a stirrer like patent document 1, 2 mentioned above. This is because the sintering raw material to be granulated is a raw material with good granulation property including particles (fine particles) with a sieve mesh under 10 μm, that is, a sintering raw material containing an easy granulation raw material.
When quick lime is added to the sintering raw material containing this easily granulated raw material, the sintering raw material is originally good in granulation property, so that the improvement effect of the sintering productivity due to the addition of quick lime does not appear much. For this reason, even if quick lime is divided and added to such a sintering raw material, the improvement rate of the sintering productivity is in a range that varies between 0.5 to 1%, and the influence due to the fluctuation of the addition ratio is not much recognized. I can't.
Therefore, conventionally, no quick lime addition device has been installed on both the conveyor and the stirrer until the equipment cost is increased. However, in the case of a sintering raw material containing (consisting of) a difficult-to-granulate fine powder raw material to be granulated by the present invention, by installing a quicklime adding device on both the conveyor and the stirrer, the sintering productivity Can be obtained, and an effect commensurate with the equipment cost can be obtained.

続いて、上記した図2と同様の試験方法で、撹拌機の撹拌羽根の周速を2m/秒にした(高速撹拌機を使用した)場合について、焼結原料(難造粒性微粉原料)に添加する生石灰を、コンベアと撹拌機の双方に分割添加した際に、この分割添加の割合が焼結生産性の向上率に及ぼす影響を、図3に示す。
図3に示すように、焼結原料へ添加する生石灰の総添加量が、図2の場合と同じであっても、撹拌羽根の周速を高速化(2m/秒)することで、焼結生産性の改善効果がより大きくなることが確認された。また、生石灰を、撹拌機前のコンベア上と撹拌機内の双方に分割して、コンベア上の焼結原料と撹拌機内の焼結原料へ添加することで、焼結生産性の改善効果がより大きくなることも、同様に確認された。
Subsequently, in the case where the peripheral speed of the stirring blade of the stirrer was set to 2 m / sec (using a high-speed stirrer) by the same test method as in FIG. 2 described above, the sintered raw material (refractory granulated fine powder raw material) FIG. 3 shows the influence of the divided addition ratio on the improvement rate of the sintering productivity when the quicklime added to is added to both the conveyor and the stirrer.
As shown in FIG. 3, even if the total amount of quicklime added to the sintering raw material is the same as in FIG. 2, the peripheral speed of the stirring blade is increased (2 m / second), so that sintering is performed. It was confirmed that the improvement effect of productivity becomes larger. In addition, by dividing quicklime into both the conveyor before the stirrer and the stirrer, and adding it to the sintered raw material on the conveyor and the sintered raw material in the stirrer, the effect of improving the sintering productivity is greater. It was confirmed as well.

更に、焼結生産性の改善効果が最大となる生石灰の分割添加の割合は、焼結原料への生石灰の総添加量に影響されることなく、0.6〜0.8程度の範囲に集中していた。このことは、撹拌羽根の周速が1m/秒の場合(図2の場合)、焼結生産性の改善効果が最大となる生石灰の分割添加の割合が、生石灰の総添加量に応じて変化することと比較して、操業上、安定して、焼結生産性の改善効果を得ることが可能となることを意味する。なお、この現象は、撹拌羽根の周速の高速化により、生石灰や消石灰の機械的分散の効果がより大きくなると考えられることによる。   Furthermore, the ratio of the divided addition of quicklime that maximizes the improvement effect of the sintering productivity is concentrated in the range of about 0.6 to 0.8 without being affected by the total amount of quicklime added to the sintering raw material. Was. This means that when the peripheral speed of the stirring blade is 1 m / sec (in the case of FIG. 2), the ratio of the quick addition of lime that maximizes the improvement of the sintering productivity varies depending on the total amount of quick lime added. This means that it is possible to obtain an effect of improving the sintering productivity stably in comparison with the operation. In addition, this phenomenon is because the effect of mechanical dispersion | distribution of quicklime and slaked lime becomes larger by the increase in the peripheral speed of a stirring blade.

従って、焼結原料へ添加する生石灰を、撹拌機前のコンベア上と撹拌機内の2箇所に分割投入する方法においては、更に、撹拌機の撹拌羽根の周速を2m/秒(更に好ましくは、3m/秒)以上にすることが好ましい。
以上のことから、撹拌機は、撹拌羽根の周速を2m/秒以上にできるものであれば、特に限定されるものではなく、例えば、前記した万能ミキサー等を使用できる。なお、撹拌羽根の周速の上限値は、上記した記載から特に限定していないが、世の中で一般的に使用されている撹拌機を考慮すれば、例えば、35m/秒程度である。また、撹拌羽根の直径は、0.1〜1.5m程度である。
Therefore, in the method in which quick lime to be added to the sintering raw material is divided into two places on the conveyor before the stirrer and in the stirrer, the peripheral speed of the stirring blade of the stirrer is further 2 m / second (more preferably, 3 m / sec) or more is preferable.
From the above, the stirrer is not particularly limited as long as the peripheral speed of the stirring blade can be 2 m / second or more, and for example, the above-described universal mixer can be used. Although the upper limit value of the peripheral speed of the stirring blade is not particularly limited from the above description, it is, for example, about 35 m / second in consideration of a stirrer generally used in the world. The diameter of the stirring blade is about 0.1 to 1.5 m.

なお、上記した結果は、生石灰の代わりに(又は生石灰と共に)消石灰を使用した場合も、消石灰(又は生石灰及び消石灰)の総添加量が、生石灰換算で焼結原料の全量の外掛けで0.5質量%以上6質量%以下の範囲において、同様の傾向が得られた。
また、上記した結果は、撹拌機で撹拌し造粒機で造粒するため、原料の切出し側(上流側)から焼結機側(下流側)へかけて、コンベア、撹拌機、及び造粒機が順次配置された設備を前提とし、生石灰の分割添加を、コンベア上と撹拌機内の双方に行った場合について示したが、更に造粒機内(合計3箇所)に分割添加してもよい。
In addition, when the above-mentioned result uses slaked lime instead of quick lime (or with quick lime), the total addition amount of slaked lime (or quick lime and slaked lime) is 0. A similar tendency was obtained in the range of 5 mass% to 6 mass%.
Moreover, since the above-mentioned result stirs with a stirrer and granulates with a granulator, it conveys from a raw material cutting side (upstream side) to a sintering machine side (downstream side), a conveyor, a stirrer, and granulation. The case where the addition of the quick lime is performed both on the conveyor and in the stirrer is shown on the premise of the equipment in which the machines are sequentially arranged, but may be further added in the granulator (three places in total).

上記した方法で、コンベア上と撹拌機内(又は造粒機内)の双方で、生石灰を焼結原料に添加し、撹拌して造粒した(又は撹拌することなく造粒した)後、この造粒物を焼結パレットに装入することで、焼結鉱を製造できる。
以上のことから、本発明の焼結原料へのバインダーの添加方法を用いることで、生石灰や消石灰のバインダーの使用量を増加させることなく、造粒性を効率的に改善して、難造粒性を有する微粉原料(焼結原料)を使用できることを確認できた。
After the above-mentioned method, quick lime is added to the sintering raw material both on the conveyor and in the agitator (or in the granulator), and granulated by stirring (or granulated without stirring), and then granulated. Sinter can be produced by charging an object into a sintering pallet.
From the above, by using the method of adding the binder to the sintered raw material of the present invention, without increasing the amount of quicklime or slaked lime binder used, it is possible to efficiently improve the granulation, difficult granulation It was confirmed that a fine powder raw material (sintering raw material) having the property of being able to be used.

以上、本発明を、実施の形態を参照して説明してきたが、本発明は何ら上記した実施の形態に記載の構成に限定されるものではなく、特許請求の範囲に記載されている事項の範囲内で考えられるその他の実施の形態や変形例も含むものである。例えば、前記したそれぞれの実施の形態や変形例の一部又は全部を組合せて本発明の焼結原料へのバインダーの添加方法を構成する場合も本発明の権利範囲に含まれる。   As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included. For example, a case where the method for adding the binder to the sintering raw material of the present invention is configured by combining some or all of the above-described embodiments and modifications is also included in the scope of the right of the present invention.

Claims (2)

鉄鉱石として、500μmアンダーが50質量%以上かつ10μmアンダーが5質量%以下の粒度の粉鉱石である微粉原料を用いる焼結原料に、生石灰及び消石灰のいずれか1又は2からなるバインダーを、生石灰換算で前記焼結原料の全量の外掛けで0.5質量%以上6質量%以下の量加え、撹拌機で撹拌して造粒機で造粒するに際し、少なくとも前記撹拌機内及び該撹拌機の上流側に配置された原料搬送コンベア上で、前記バインダーを前記焼結原料に添加することを特徴とする焼結原料へのバインダーの添加方法(但し、前記原料搬送コンベア上で前記バインダーを前記焼結原料へ添加する方法のうち、前記バインダーを搬送用の空気又は水に混合して吹き付ける方法、及びフィーダから落下している前記バインダーに空気又は水を吹き付ける方法を除く)。   As the iron ore, a binder made of quick lime and slaked lime is used as a sintering raw material that is a fine powder raw material having a particle size of 500 μm under 50% by mass and 10 μm under 5% by mass. When the amount of 0.5% by mass or more and 6% by mass or less is added to the total amount of the sintered raw material in terms of conversion, the mixture is stirred with a stirrer and granulated with a granulator. A method for adding a binder to a sintered raw material, wherein the binder is added to the sintered raw material on a raw material conveyor disposed upstream (however, the binder is baked on the raw material conveyor). Among the methods of adding to the binder, the method of spraying the binder mixed with air or water for transport and the method of blowing air or water to the binder falling from the feeder Except the method of attaching). 請求項1記載の焼結原料へのバインダーの添加方法において、前記撹拌機の撹拌羽根の周速を2m/秒以上にすることを特徴とする焼結原料へのバインダーの添加方法。   The method for adding a binder to a sintering material according to claim 1, wherein the peripheral speed of the stirring blade of the stirrer is 2 m / sec or more.
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