JP2017036480A - Manufacturing method of sintered ore - Google Patents
Manufacturing method of sintered ore Download PDFInfo
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 65
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 132
- 239000002994 raw material Substances 0.000 claims abstract description 110
- 238000005245 sintering Methods 0.000 claims abstract description 84
- 229910052742 iron Inorganic materials 0.000 claims abstract description 65
- 238000005469 granulation Methods 0.000 claims abstract description 58
- 230000003179 granulation Effects 0.000 claims abstract description 58
- 238000009775 high-speed stirring Methods 0.000 claims abstract description 23
- 238000003756 stirring Methods 0.000 claims description 42
- 230000002093 peripheral effect Effects 0.000 claims description 27
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 26
- 239000011361 granulated particle Substances 0.000 claims description 25
- 235000019738 Limestone Nutrition 0.000 claims description 22
- 239000006028 limestone Substances 0.000 claims description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 239000000292 calcium oxide Substances 0.000 claims description 13
- 235000012255 calcium oxide Nutrition 0.000 claims description 13
- 238000007781 pre-processing Methods 0.000 claims description 13
- 239000004449 solid propellant Substances 0.000 claims description 11
- 239000013078 crystal Substances 0.000 claims description 10
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 9
- 239000000920 calcium hydroxide Substances 0.000 claims description 9
- 235000011116 calcium hydroxide Nutrition 0.000 claims description 9
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 9
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 7
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 7
- 239000004571 lime Substances 0.000 claims description 7
- 239000002245 particle Substances 0.000 abstract description 101
- 239000000843 powder Substances 0.000 abstract description 30
- 238000002156 mixing Methods 0.000 abstract description 25
- 230000002708 enhancing effect Effects 0.000 abstract 1
- 239000008188 pellet Substances 0.000 description 40
- 238000000034 method Methods 0.000 description 30
- 238000009826 distribution Methods 0.000 description 19
- 238000005315 distribution function Methods 0.000 description 14
- 239000011362 coarse particle Substances 0.000 description 10
- 239000000571 coke Substances 0.000 description 10
- 239000010419 fine particle Substances 0.000 description 10
- 239000008187 granular material Substances 0.000 description 8
- 230000008021 deposition Effects 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000010304 firing Methods 0.000 description 6
- 230000035699 permeability Effects 0.000 description 6
- 239000006185 dispersion Substances 0.000 description 5
- 229910052770 Uranium Inorganic materials 0.000 description 4
- 238000004220 aggregation Methods 0.000 description 4
- 230000002776 aggregation Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000007771 core particle Substances 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 230000001788 irregular Effects 0.000 description 4
- 238000010298 pulverizing process Methods 0.000 description 4
- 239000011044 quartzite Substances 0.000 description 4
- 239000002893 slag Substances 0.000 description 4
- NWBJYWHLCVSVIJ-UHFFFAOYSA-N N-benzyladenine Chemical compound N=1C=NC=2NC=NC=2C=1NCC1=CC=CC=C1 NWBJYWHLCVSVIJ-UHFFFAOYSA-N 0.000 description 2
- 229910000805 Pig iron Inorganic materials 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- WYTGDNHDOZPMIW-RCBQFDQVSA-N alstonine Natural products C1=CC2=C3C=CC=CC3=NC2=C2N1C[C@H]1[C@H](C)OC=C(C(=O)OC)[C@H]1C2 WYTGDNHDOZPMIW-RCBQFDQVSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- WETINTNJFLGREW-UHFFFAOYSA-N calcium;iron;tetrahydrate Chemical compound O.O.O.O.[Ca].[Fe].[Fe] WETINTNJFLGREW-UHFFFAOYSA-N 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 239000003818 cinder Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000003750 conditioning effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000004132 cross linking Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000012256 powdered iron Substances 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
- C22B1/2406—Binding; Briquetting ; Granulating pelletizing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/12—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic in rotating drums
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/14—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic in rotating dishes or pans
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/16—Sintering; Agglomerating
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- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
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- General Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Glanulating (AREA)
Abstract
Description
本発明は、焼結原料について造粒後ＤＬ式焼結機などを用いて製造される、高炉原料としての焼結鉱の製造方法に関する。 The present invention relates to a method for producing sintered ore as a blast furnace raw material, which is produced by using a DL-type sintering machine after granulation for a sintered raw material.
焼結鉱は、複数銘柄の粉鉄鉱石（一般に、１２５〜１０００μｍ程度のシンターフィードと呼ばれているもの）に、石灰石や珪石、蛇紋岩等の副原料粉と、ダスト、スケール、返鉱等の雑原料粉と、粉コークス等の固体燃料とを適量ずつ配合した焼結配合原料に、水分を添加して混合−造粒し、得られた造粒原料を焼結機に装入して焼成することによって製造される。その焼結配合原料は、一般に、水分を含むことで造粒時に互いに凝集して擬似粒子となる。そして、この擬似粒子化した焼結用造粒原料は、焼結機のパレット上に装入されたとき、焼結原料装入層の良好な通気を確保するのに役立ち、焼結反応を円滑に進める。 Sintered ore consists of several brands of fine iron ore (generally called sinter feed of about 125 to 1000 μm), auxiliary raw material powders such as limestone, quartzite, and serpentine, and dust, scale, return ore, etc. The raw material powder and solid fuel such as powdered coke are mixed in an appropriate amount to add the moisture, mix and granulate, and charge the resulting granulated material into the sintering machine. Manufactured by firing. Generally, the sintered blending raw material contains moisture, and aggregates into pseudo particles during granulation. This pseudo-granulated raw material for sintering, when placed on the pallet of the sintering machine, helps to ensure good ventilation of the sintered raw material charging layer and facilitates the sintering reaction. Proceed to
ところで、焼結用粉鉄鉱石は、近年、高品質鉄鉱石の枯渇によって低品位化している。即ち、鉄鉱石の低品位化は、スラグ成分の増加や微粉化の傾向を招き、そのためにアルミナ含有量の増大や微粉比率の増大による造粒性を低下させる。その一方で、高炉で使用する焼結鉱としては、高炉での溶銑製造コストの低減やＣＯ２発生量の低減という観点から低スラグ比、高被還元性、高強度のものが求められている。 By the way, in recent years, powder iron ore for sintering has been lowered in quality by depletion of high-quality iron ore. That is, the lower grade of iron ore leads to an increase in slag components and a tendency to pulverization, and therefore the granulation properties are decreased due to an increase in the alumina content and an increase in the pulverization ratio. On the other hand, sintered ore used in the blast furnace is required to have a low slag ratio, high reducibility, and high strength from the viewpoint of reducing hot metal production cost in the blast furnace and reducing CO 2 generation amount. .
焼結用粉鉄鉱石を取り巻くこのような環境の中で、最近、ペレットフィードと呼ばれるペレット用として用いられてきた難造粒性の微粉鉄鉱石を使って、高品質の焼結鉱を製造するための技術が提案されている。例えば、こうした従来技術の１つに、Hybrid Pelletized Sinter法（以下、「ＨＰＳ法」という）がある。この技術は、ペレットフィードのような微粉鉄鉱石を多量に含む焼結配合原料をドラムミキサーとペレタイザーとを使って造粒することにより、低スラグ比・高被還元性の焼結鉱を製造しようというものである（特許文献１、特許文献２、特許文献３、特許文献４、特許文献５）。
In such an environment surrounding powdered iron ore for sintering, high-quality sintered ore is produced using the hardly granulated fine iron ore that has been used for pellets recently called pellet feed. Techniques for this have been proposed. For example, one such conventional technique is the Hybrid Pelletized Sinter method (hereinafter referred to as “HPS method”). In this technology, low-slag-ratio, highly-reducible sintered ore is produced by granulating a sintering compounded raw material containing a large amount of fine iron ore such as pellet feed using a drum mixer and pelletizer. (
その他、焼結原料粉造粒工程の前に、高速回転ミキサーにて調湿混合する方法（特許文献６）や、造粒工程の前に、微粉鉄鉱石と製鉄ダストとを撹拌混合機で予め混合する方法（特許文献７）、微粉（ペレットフィード）をアイリッヒミキサーで予め混合処理したのちドラムミキサーにて造粒する方法（特許文献８）、粒径２５０μｍ以下の粒子を６０重量％以上含む鉄鉱石原料を混練後、ドラムミキサーで造粒する方法（特許文献９）などの提案もある。 In addition, prior to the sintering raw material powder granulation step, a method of conditioning and mixing with a high-speed rotary mixer (Patent Document 6), and before the granulation step, fine iron ore and iron dust are preliminarily mixed with a stirring mixer. A method of mixing (Patent Document 7), a method of premixing fine powder (pellet feed) with an Eirich mixer and then granulating with a drum mixer (Patent Document 8), containing 60% by weight or more of particles having a particle size of 250 μm or less There is also a proposal such as a method (Patent Document 9) in which an iron ore raw material is kneaded and then granulated with a drum mixer.
しかしながら、ペレットフィードなどの微粉鉄鉱石、とくに超微粉鉄鉱石を多量に含む焼結配合原料は、これを前記特許文献１〜５に記載されているようなＨＰＳ法を用いて造粒したり、前記特許文献６〜９に記載されているような高速撹拌機などを使って予め混合処理したりする方法では、次のような問題がある。
However, the sintered blending raw material containing a large amount of fine iron ore, particularly ultra fine iron ore, such as pellet feed, is granulated using the HPS method as described in
すなわち、図１に示すように、これらの方法では、細粒（０．５ｍｍ未満）のみならず、粗大（１０ｍｍ超）な擬似粒子が多く生成する。その理由は、ペレットフィードのような微粉鉄鉱石は、濡れ性が同じであれば、細粒ほど比表面積が大きいので水分を吸収しやすく、かつ粉体間に多くの水分を保持しやすいため、個々の微粉鉄鉱石が水分を優先的に吸収しやすくなるからである。その結果、微粉どうしが単に凝集しただけにすぎないものや、核粒子のまわりに微粉が付着した形態の粒径の不揃いな粗大な擬似粒子が生成しやすくなるのである。さらに、これらの方法では粉体の付着の問題や、微粉や水分の均一分散が悪く、かつ設備稼働率の低下を招くという問題もある。 That is, as shown in FIG. 1, in these methods, not only fine particles (less than 0.5 mm) but also large (greater than 10 mm) pseudo particles are generated. The reason is that fine iron ore like pellet feed, if the wettability is the same, the finer the specific surface area, the greater the specific surface area, so it is easy to absorb moisture and hold more moisture between the powders. It is because each fine iron ore becomes easy to absorb moisture preferentially. As a result, it is easy to generate coarse pseudo particles in which the fine particles are simply aggregated or coarse particles having irregular particle sizes in a form in which the fine particles adhere around the core particles. Furthermore, these methods also have problems of adhesion of powder, poor uniform dispersion of fine powder and moisture, and a decrease in equipment operation rate.
この点に関しては、発明者らが行なった下記の実験からも明らかである。まず、この実験では、ペレットフィードなどの難造粒性の微粉鉄鉱石（バナジウム含有量：４０ｍａｓｓ％）を含有する配合原料を使用して造粒し、この時、生成した造粒粒子（擬似粒子）の粒度分布とペレットフィードの粒度分布を計測した。その結果を図２に示す。まず、図２（ａ）に示すように、焼結配合原料中にペレットフィードを多量に含むものは、ペレットフィードを含まないものに比べると、粗粒（８ｍｍ超）になる割合が高くなった。その重量割合は７５ｍａｓｓ％程度に達した。また、造粒した疑似粒子中のペレットフィードの粒度分布（図２（ｂ））は、造粒粒子の粒度分布（図２（ａ））と同様の傾向を示した。即ち、粗粒中のペレットフィードは、その割合が８０ｍａｓｓ％程度と高く、ペレットフィードの殆どが該粗粒中に偏在することがわかった。このことから、粗大な擬似粒子というのは、ペレットフィードどうしが凝集し合うことで形成されていることが分る。そして、粗粒領域に属するこの擬似粒子は、また、水分量も高いということが分った（図２（ｂ））。このことから、水分はペレットフィードが優先して吸収し、そのためにペレットフィードどうしが凝集し合って粗大な擬似粒子を形成し、その結果、粗大な疑似粒子中には多くの水分が吸収されることになる。 This point is also clear from the following experiment conducted by the inventors. First, in this experiment, granulation was performed using a blended raw material containing finely granulated iron ore (vanadium content: 40 mass%) such as pellet feed, and at this time, the generated granulated particles (pseudo particles) ) And the particle size distribution of the pellet feed. The result is shown in FIG. First, as shown in FIG. 2 (a), those containing a large amount of pellet feed in the sintered blending material have a higher proportion of coarse particles (over 8 mm) than those containing no pellet feed. . The weight ratio reached about 75 mass%. In addition, the particle size distribution of the pellet feed in the granulated pseudo particles (FIG. 2B) showed the same tendency as the particle size distribution of the granulated particles (FIG. 2A). That is, the ratio of the pellet feed in the coarse grains was as high as about 80 mass%, and it was found that most of the pellet feed was unevenly distributed in the coarse grains. From this, it can be seen that coarse pseudo-particles are formed by aggregation of pellet feeds. And it turned out that this pseudo particle which belongs to a coarse-grain area | region also has a high moisture content (FIG.2 (b)). Therefore, the pellet feed is preferentially absorbed by the pellet feed, and therefore the pellet feeds aggregate to form coarse pseudo particles, and as a result, a large amount of moisture is absorbed in the coarse pseudo particles. It will be.
このようにペレットフィード等の微粉鉄鉱石を多く含む配合原料は、これを造粒すると、どうしても粒径が不揃いになると共に、微粉どうしが単に凝集したにすぎないものとなって、結合強度の弱い粗大な擬似粒子を生成しやすくなる。そのため、このような疑似粒子を焼結機のパレット上に装入して堆積させると、図３（ａ）に示すように、焼結原料装入層は密な堆積構造となって、かさ密度が大きくなる。しかも、このような粗大な擬似粒子は、焼結機のパレット上に一定の層厚で堆積させると、該擬似粒子に荷重（圧縮力）が加わったときに壊われやすくなるため、粉化して空隙率の低下を招き、ひいては通気性の悪化を招いて焼結機操業の阻害要因になる。その結果として、焼結時間が長くなり、焼結鉱の歩留低下を招いて生産性が低下するおそれがある。さらには、造粒に用いられるバインダーである生石灰の使用量を増加せざるを得なくなり、焼結鉱製造コストの増大を招き、後工程において粉コークス等の固体燃料を被覆する際に、焼結原料全体としての粉コークス等の賦存状態の不均一を招くようになる。その結果、燃焼や着熱不良を招いて焼成速度を低下させる。 In this way, the blended raw material containing a large amount of fine iron ore such as pellet feed, when granulated, inevitably becomes uneven in particle size, and the fine powder is merely agglomerated, and the bond strength is weak. Coarse pseudo particles are easily generated. Therefore, when such pseudo particles are charged and deposited on the pallet of the sintering machine, as shown in FIG. 3 (a), the sintered raw material charging layer has a dense deposition structure and a bulk density. Becomes larger. Moreover, if such coarse pseudo-particles are deposited on a pallet of a sintering machine with a certain layer thickness, they are easily broken when a load (compressive force) is applied to the pseudo-particles. This leads to a decrease in porosity, which in turn causes deterioration in air permeability, which becomes an impediment to sintering machine operation. As a result, the sintering time becomes longer, and the yield of sintered ore may be reduced, leading to a decrease in productivity. Furthermore, the amount of quicklime, which is a binder used for granulation, must be increased, resulting in an increase in the production cost of sintered ore, and sintering when coating solid fuel such as powdered coke in the subsequent process. As a result, non-uniformity of the existing state of the powdered coke and the like as the whole raw material is caused. As a result, combustion and poor heat receiving are caused and the firing rate is lowered.
本発明の目的は、微粉鉄鉱石を焼結鉱製造用配合原料として使用する場合において、適正な擬似粒子を造粒して、焼結機での生産性を向上させることができる焼結鉱の製造方法を提案することにある。 The object of the present invention is to use a fine ore as a raw material for the production of sintered ore, granulate appropriate pseudo particles, and improve the productivity of the sintered ore. It is to propose a manufacturing method.
前述した従来技術が抱えている課題について鋭意検討を重ねた結果、発明者らは、所定の粒度の微粉の所定量を有する焼結原料を高速撹拌装置による事前処理することで、その後の造粒時に、粒径が不揃いで結合強度の弱い粗大な造粒粒子（擬似粒子）が発生するのを阻止でき、適正な擬似粒子を造粒して、焼結機での生産性を向上させることができることを突き止めて、本発明を開発した。 As a result of intensive investigations on the problems of the prior art described above, the inventors have previously processed a granulated raw material having a predetermined amount of fine powder having a predetermined particle size by a high-speed agitator, and thereafter granulated. Sometimes it is possible to prevent the generation of coarse granulated particles (pseudo particles) with uneven particle size and weak bond strength, and to improve the productivity in the sintering machine by granulating appropriate pseudo particles. The present invention was developed after finding out what can be done.
即ち、本発明は、焼結原料を造粒後焼結機で焼結して焼結鉱を得る焼結鉱の製造方法において、１２５μｍ以下の微粉鉄鉱石を１０〜５０ｍａｓｓ％含む焼結原料の事前処理を高速撹拌装置で行った後、造粒装置で造粒を行うことを特徴とする焼結鉱の製造方法にある。 That is, the present invention relates to a method for producing sintered ore in which a sintered raw material is obtained by granulating a sintered raw material after sintering with a sintering machine, and containing 10 to 50 mass% of fine iron ore of 125 μm or less. In the method for producing a sintered ore, the pretreatment is performed with a high-speed agitator and then granulated with a granulator.
なお、前記のように構成される本発明に係る焼結鉱の製造方法においては、
（１）前記高速撹拌装置の羽根の周速Ｕ（ｍ／ｓ）に対して、前記高速撹拌装置による撹拌時間ｔ（秒）とした場合に、３００＜Ｕ＊ｔ＜２０００の条件を満たすように事前処理を行うこと、
（２）前記高速撹拌装置の羽根の周速Ｕ（ｍ／ｓ）に対して、前記高速撹拌装置による撹拌時間ｔ（秒）とした場合に、４００＜Ｕ＊ｔ＜１２００の条件を満たすように事前処理を行うこと、
（３）前記造粒装置は、ドラムミキサーおよび／またはディスクペレタイザーであること、
（４）前記造粒装置の造粒においては、処理した原料に対して石灰石を被覆して、その造粒粒子の表面に固体系燃料を被覆すること、
（５）前記焼結原料としては、少なくとも１種類以上は結晶水鉱石を含み、結晶水の含有量を４ｍａｓｓ%以上としたこと、
（６）前記１２５μｍ以下の微粉鉄鉱石に石灰石を５ｍａｓｓ％以上含むこと、
（７）前記高速撹拌機で処理する焼結原料には、被覆する石灰分以外に、消石灰もしくは生石灰を３ｍａｓｓ％以下添加すること、
（８）前記高速撹拌機に使用する焼結原料において、微粉鉄鉱石の割合が３０ｍａｓｓ％以上においては原料を乾燥処理すること、
がより好ましい解決手段となるものと考えられる。
In the method of manufacturing a sintered ore according to the present invention configured as described above,
(1) With respect to the peripheral speed U (m / s) of the blades of the high-speed stirrer, when the stirring time t (seconds) by the high-speed stirrer is used, the condition of 300 <U * t <2000 is satisfied. Pre-processing,
(2) With respect to the peripheral speed U (m / s) of the blades of the high-speed stirrer, when the stirring time t (seconds) by the high-speed stirrer is used, the condition of 400 <U * t <1200 is satisfied. Pre-processing,
(3) the granulator is a drum mixer and / or a disk pelletizer;
(4) In the granulation of the granulator, the treated raw material is coated with limestone, and the surface of the granulated particles is coated with a solid fuel,
(5) As the sintering raw material, at least one kind contains crystal water ore, and the content of crystal water is 4 mass% or more,
(6) containing 5 mass% or more of limestone in the fine iron ore of 125 μm or less,
(7) In addition to the lime content to be coated, slaked lime or quicklime is added in an amount of 3 mass% or less to the sintered raw material to be processed with the high-speed stirrer.
(8) In the sintering raw material used for the high-speed stirrer, when the proportion of fine iron ore is 30 mass% or more, the raw material is dried.
Is considered to be a more preferable solution.
本発明は、微粉鉄鉱石と細粒とが強固に凝集したもの、または核粒子のまわりに微粉鉄鉱石等が付着した構造の、粒径が比較的揃って粒度分布が小さい擬似粒子からなる焼結用造粒原料の製造方法を提案するものである。こうした方法によって得られた焼結用造粒原料は、これを焼結機のパレット上に装入したとき、パレット上に形成される焼結原料装入層の密度の低減や、通気性の向上に伴う焼成時間の短縮を図ることができ、ひいては高品質焼結鉱の生産性を向上させるのに有効である。 In the present invention, fine iron ore and fine particles are agglomerated firmly, or a structure in which fine iron ore or the like is adhered around the core particles is a sintered particle composed of pseudo particles having a relatively uniform particle size and a small particle size distribution. The manufacturing method of the granulation raw material for ligation is proposed. When the granulated raw material for sintering obtained by such a method is placed on a pallet of a sintering machine, the density of the sintered raw material charging layer formed on the pallet is reduced and the air permeability is improved. Thus, the firing time can be shortened, which is effective in improving the productivity of high-quality sintered ore.
＜本発明の特徴事項である造粒前の事前処理について＞
図４は、本発明の焼結鉱の製造方法を実施する設備列の一例を説明するための図である。図４に従って本発明の焼結鉱の製造方法を説明すると、まず、１２５μｍ以下の微粉鉄鉱石を１０〜５０ｍａｓｓ％含む焼結原料１１を準備する。焼結原料１１は、上述した１０〜５０ｍａｓｓ％の１２５μｍ以下のペレットフィードやテーリング鉱である微粉鉄鉱石と、残部がシンダーフィードである粉鉄鉱石の他、返鉱、珪石、石灰、生石灰などのその他の原料と、からなることが好ましい。なお、本発明において、焼結原料１１として、１２５μｍ以下の微粉鉄鉱石を１０〜５０ｍａｓｓ％含むものに限定した理由は、以下の通りである。
<About pretreatment before granulation which is a feature of the present invention>
FIG. 4 is a diagram for explaining an example of an equipment row for carrying out the method for producing a sintered ore according to the present invention. The method for producing a sintered ore according to the present invention will be described with reference to FIG. 4. First, a sintering
すなわち、上記微粉鉄鉱石の発明範囲は粒径が不揃いで結合強度が弱い粗大な粒子が出来るために設定したものであり、１０％未満では結合強度の弱い擬似粒子が出来ない等、また５０％超えでは同様に結合強度が弱い粗大な粒子が出来る問題があるが、実質的に１２５μｍ以下の微粉鉄鉱石を５０ｍａｓｓ％超えて配合することはなく上限を５０％とした。粒径を１２５μｍ以下とした理由は、粒径１２５μｍ以下においては、水分を添加した粉体充填層における粒子層同士の接着性を表す付着力が増加するために造粒性が大きく異なる挙動を示したため、１２５μｍを粒度の区間に設定した。 That is, the invention range of the fine iron ore is set to produce coarse particles with irregular particle sizes and weak bond strength. If it is less than 10%, pseudo particles with low bond strength cannot be formed, and 50%. If exceeding the above, there is a problem that coarse particles having a weak bond strength can be formed in the same manner. However, the upper limit is set to 50% without adding more than 50 mass% of fine iron ore of 125 μm or less. The reason why the particle size is set to 125 μm or less is that when the particle size is 125 μm or less, the adhesion force representing the adhesion between the particle layers in the powder-filled layer to which moisture has been added increases, and thus the granulation property is greatly different. Therefore, 125 μm was set as the particle size section.
次に、準備した焼結原料１１の事前処理を高速撹拌機１２で実施する。高速撹拌機１２の目的は、粗大な造粒粒子の生成を抑止するために、粗大な造粒粒子の種となる微粉の凝集体を造粒前に壊砕することにある。微粉の凝集体を効率的に壊砕するためには、ミクロ的には、凝集体自身に、せん断力を加えて、直接微粉を剥離させることが有効である。高速撹拌機１２の一例としては、たとえば、アイリッヒミキサー(日本アイリッヒ製)、ペレガイアミキサー（北川鉄工製）、プロシェアミキサー(太平洋機工)などを用いることができる。このうちアイリッヒミキサーは、「高速撹拌造粒」機として知られ、液体架橋による粒子の凝集、成長に伴う造粒機能を併せもつ設備である。
Next, pretreatment of the prepared sintered
次に、事前処理を高速撹拌機１２で行われた焼結原料１１を、ドラムミキサー１３によって、水分添加の下で撹拌混合して造粒する。造粒後の焼結原料１１は焼結機１４に供給され、焼結機１４において焼結鉱となる。そして、焼結鉱は、コークス、石灰石などとともに高炉原料として高炉１５に供給されて銑鉄を製造する。
Next, the sintered
本発明の特徴となる、造粒前の事前処理の影響を調べるため、１２５μｍの微粉鉄鉱石を３０ｍａｓｓ％含む同じ焼結原料に対し、図５に示すように、高速撹拌ミキサー（アイリッヒミキサー）とドラムミキサーとにより、造粒前の事前処理を実施した。それぞれのミキサーによる混合時間を０〜１６０秒間で変化させ、事前処理後ドラムミキサーで１６０秒間造粒を行った後の焼結原料に対し粒度分布を求め、それに基づき以下の式で定義されるＩｓ、Ｉｐを求め、それぞれの調和平均径Ｄｐ（ｍｍ）、粒度分布関数Ｉｓｐ、さらには、焼結前充填層の相対通過風量を図６、図７および図８に示す。なお、いずれの例においても、ドラムミキサーによる事前処理が０秒の例が従来例となる。高速撹拌ミキサーに使用により調和平均径が増加して、粒度分布関数Ｉｓｐによる粒度分布がシャープになる効果が得られた。相対通過風量についても増加効果が得られた。ここで、相対通過風量が大きいほど値ほど、一定負圧で操業する焼結機においてガス量が大きくすることができ、生産性が高くなる。 In order to investigate the influence of pretreatment before granulation, which is a feature of the present invention, as shown in FIG. 5, a high-speed stirring mixer (Eirich mixer) is used for the same sintered raw material containing 30 mass% of 125 μm fine iron ore. And a drum mixer were used for pretreatment before granulation. The mixing time by each mixer is changed from 0 to 160 seconds, the particle size distribution is obtained for the sintered raw material after granulation for 160 seconds by the drum mixer after the pretreatment, and Is defined by the following formula based on it. , Ip, and the harmonic mean diameter Dp (mm), the particle size distribution function Isp, and the relative passing air volume of the packed bed before sintering are shown in FIG. 6, FIG. 7, and FIG. In any of the examples, an example in which the pre-processing by the drum mixer is 0 seconds is a conventional example. The harmonic average diameter was increased by using it in a high-speed stirring mixer, and the effect of sharpening the particle size distribution by the particle size distribution function Isp was obtained. The effect of increasing the relative airflow was also obtained. Here, the larger the relative passing air volume, the larger the value, the higher the gas volume in the sintering machine operating at a constant negative pressure, and the higher the productivity.
Ｄｐ＝１／Σ（ｗｉ／ｄｉ）
Ｉｓｐ＝１００√（Ｉｓ×Ｉｐ）
Ｉｓ＝Ｄｐ２Σｗｉ（１／ｄｉ−１／Ｄｐ）２
Ｉｐ＝（１／Ｄｐ）２Σｗｉ（ｄｉ−Ｄｐ）２
ここで、
Ｄｐ：調和平均径（ｍｍ）
ｗｉ：区間における重量存在率（−）
ｄｉ：区間の代表平均径（ｍｍ）
Ｉｓｐ：粒度分布関数
Ｉｓ：細粒における粒度分布関数（−）
Ｉｐ：粗粒における粒度分布関数（−）
Dp = 1 / Σ (wi / di)
Isp = 100√ (Is × Ip)
Is = Dp 2 Σwi (1 / di−1 / Dp) 2
Ip = (1 / Dp) 2 Σwi (di−Dp) 2
here,
Dp: harmonic mean diameter (mm)
wi: Weight abundance ratio in the section (−)
di: Typical average diameter of the section (mm)
Isp: particle size distribution function Is: particle size distribution function in fine particles (-)
Ip: Particle size distribution function (−) in coarse particles
図６、図７および図８の結果から、造粒前の事前処理を高速撹拌ミキサーで実施した本発明例は、事前処理を行わなかった従来例および造粒前の事前処理をドラムミキサーで実施した比較例に比べて、高い調和平均径（図６）、低い粒度分布関数(図７)および高い焼結前充填層の相対通過風量（図８）を得ることができ、良好な性状の焼結原料が得られることがわかった。 From the results of FIGS. 6, 7 and 8, the example of the present invention in which the pretreatment before granulation was performed with a high-speed stirring mixer was performed in the conventional example in which the pretreatment was not performed and the pretreatment before granulation was performed with a drum mixer. Compared with the comparative example, a high harmonic mean diameter (Fig. 6), a low particle size distribution function (Fig. 7) and a high relative passing air volume (Fig. 8) of the packed bed before sintering can be obtained. It was found that a ligation raw material was obtained.
＜高速撹拌機の好適な操業条件について＞
本発明の焼結鉱の製造方法における高速撹拌機の好適な操業条件を調べるため、１２５μｍの微粉鉄鉱石を３０ｍａｓｓ％含む同じ焼結原料に対し、高速撹拌機の高速で回転する羽根の周速Ｕ（ｍ／ｓ）と撹拌時間ｔ（秒）との関係に着目した。そして、周速ＵをＵ＝９ｍ／ｓの条件に固定して撹拌時間ｔをｔ＝０〜２４０秒の範囲で変えた例と、撹拌時間ｔをｔ＝１２０秒の条件に固定して周速ＵをＵ＝０〜１８ｍ／ｓの範囲で変えた例と、周速ＵをＵ＝６ｍ／ｓの条件に固定して撹拌時間を０〜２４０秒の範囲で変えた例と、について、造粒後焼結機で焼結して得た焼結鉱の生産率を求めるとともに、（Ｕ＊ｔ）で整理した。
<Suitable operating conditions for high-speed agitator>
In order to investigate suitable operating conditions of the high-speed stirrer in the method for producing sintered ore of the present invention, the peripheral speed of the blade rotating at a high speed of the high-speed stirrer with respect to the same sintered raw material containing 30 mass% of 125 μm fine iron ore Attention was paid to the relationship between U (m / s) and stirring time t (seconds). The example in which the circumferential speed U is fixed to the condition of U = 9 m / s and the stirring time t is changed in the range of t = 0 to 240 seconds, and the stirring time t is fixed to the condition of t = 120 seconds and the circumferential speed U is fixed. Regarding an example in which the speed U is changed in the range of U = 0 to 18 m / s, and an example in which the peripheral speed U is fixed to the condition of U = 6 m / s and the stirring time is changed in the range of 0 to 240 seconds. After the granulation, the production rate of sintered ore obtained by sintering with a sintering machine was obtained, and the production rate was arranged by (U * t).
ここで、粒径が不揃いで結合強度の弱い粗大な造粒粒子（擬似粒子）が発生するのを阻止でき、適正な擬似粒子を造粒することができる条件として、周速Ｕに撹拌時間ｔを乗じたＵ＊ｔについて着目した。Ｕ＊ｔの次元としては長さ「ｍ」の次元を持った物理量を持っており、高速で回転する羽根により与えられた移動距離と考えられるため、異なる周速および撹拌時間により整理できると考えた。高速撹拌機において、上部より投入された原料が下部へ流れ出る構造であることから、装置内の原料の占有率が一定の場合、投入速度が変更された場合に撹拌時間が変化する。その際、適切な範囲Ｕ＊ｔを定めることで安定した品質の焼結鉱が製造可能になることがわかる。 Here, as a condition for preventing generation of coarse granulated particles (pseudoparticles) having uneven particle sizes and weak bond strength, it is possible to granulate appropriate pseudoparticles at a circumferential speed U at a stirring time t. We focused on U * t multiplied by. The dimension of U * t has a physical quantity with a dimension of “m” in length, and is considered to be a moving distance given by a blade rotating at high speed. Therefore, it can be arranged by different peripheral speeds and stirring times. It was. In the high-speed stirrer, since the raw material charged from the upper part flows out to the lower part, the stirring time changes when the raw material occupancy in the apparatus is constant or the charging speed is changed. At that time, it can be seen that a stable quality ore can be produced by setting an appropriate range U * t.
周速ＵをＵ＝９ｍ／ｓの条件に固定して撹拌時間ｔをｔ＝０〜２４０秒の範囲で変えた場合の生産率（ｔ／ｈｒ／ｍ２）と（Ｕ＊ｔ）との関係を図９及び以下の表１に示し、撹拌時間ｔをｔ＝１２０秒の条件に固定して周速ＵをＵ＝０〜１８ｍ／ｓの範囲で変えた場合の生産率（ｔ／ｈｒ／ｍ２）と（Ｕ＊ｔ）との関係を図１０及び以下の表２に示し、周速ＵをＵ＝６ｍ／ｓの条件に固定して撹拌時間ｔをｔ＝０〜２４０秒の範囲で変えた場合の生産率（ｔ／ｈｒ／ｍ２）と（Ｕ＊ｔ）との関係を図１１及び以下の表３に示す。 The production rate (t / hr / m 2 ) and (U * t) when the peripheral speed U is fixed at U = 9 m / s and the stirring time t is changed in the range of t = 0 to 240 seconds. 9 and Table 1 below, the production rate (t / hr) when the stirring time t is fixed at t = 120 seconds and the peripheral speed U is changed in the range of U = 0 to 18 m / s. / M 2 ) and (U * t) are shown in FIG. 10 and Table 2 below, and the peripheral speed U is fixed at U = 6 m / s and the stirring time t is t = 0 to 240 seconds. The relationship between the production rate (t / hr / m 2 ) and (U * t) when changed within the range is shown in FIG. 11 and Table 3 below.
図９〜図１１（表１〜表３のデータに基づく）の結果から、Ｕ＜８ｍ／ｓとＵ≧８ｍ／ｓの２条件ついて（Ｕ＊ｔ）と生産率との関係を求め、図１２に散布図として示す。図１２の結果から、いずれの例において、Ｕ＊ｔを３００＜Ｕ＊ｔ＜２０００の条件を満たすように高速撹拌機により事前処理を行うことが好ましく、Ｕ＊ｔを４００＜Ｕ＊ｔ＜１２００の条件を満たすように高速撹拌機により事前処理を行うことが更に好ましいことがわかる。いずれの例においてもＵ＊ｔの好適範囲がほぼ同じであることから、上記Ｕ＊ｔの範囲は、高速撹拌機の周速および撹拌時間の種々の例についても好適例として一般化できることがわかる。 From the results of FIGS. 9 to 11 (based on the data in Tables 1 to 3), the relationship between (U * t) and the production rate is obtained for two conditions of U <8 m / s and U ≧ 8 m / s. 12 shows a scatter diagram. From any of the results shown in FIG. 12, in any example, it is preferable to perform pretreatment with a high-speed stirrer so that U * t satisfies the condition of 300 <U * t <2000, and U * t is set to 400 <U * t < It can be seen that it is more preferable to perform pretreatment with a high-speed stirrer so as to satisfy the condition of 1200. Since the preferable range of U * t is almost the same in any example, it can be understood that the range of U * t can be generalized as a preferable example for various examples of the peripheral speed and stirring time of the high-speed stirrer. .
また、図９の結果から、高速撹拌装置で行う焼結原料の事前処理において、高速撹拌装置の高速で回転する羽根の周速Ｕを９（ｍ／ｓ）としたとき、高速撹拌装置の撹拌時間を３０秒以上とすることが好ましいことがわかる。さらに、図１０の結果から、高速撹拌装置の撹拌時間を１２０秒としたとき、高速撹拌装置の高速で回転する羽根の周速Ｕ（ｍ／ｓ）を６≦Ｕ≦１２とすることが好ましいことがわかる。さらにまた、図１１の結果から、高速撹拌装置で行う焼結原料の事前処理において、高速撹拌装置の高速で回転する羽根の周速Ｕを６（ｍ／ｓ）としたとき、高速撹拌装置の撹拌時間を６０秒以上とすることが好ましいことがわかる。 Moreover, from the result of FIG. 9, in the pre-processing of the sintering raw material performed by the high-speed stirring device, when the peripheral speed U of the blade rotating at high speed of the high-speed stirring device is 9 (m / s), the stirring of the high-speed stirring device It can be seen that the time is preferably 30 seconds or more. Furthermore, from the result of FIG. 10, when the stirring time of the high-speed stirring device is 120 seconds, it is preferable that the peripheral speed U (m / s) of the blade rotating at high speed of the high-speed stirring device is 6 ≦ U ≦ 12. I understand that. Furthermore, from the result of FIG. 11, when the peripheral speed U of the blade rotating at high speed of the high-speed stirrer is 6 (m / s) in the pretreatment of the sintering raw material performed by the high-speed stirrer, It can be seen that the stirring time is preferably 60 seconds or more.
＜その他の好適な操業条件について＞
本発明の焼結鉱の製造方法では、上述した実施例における造粒装置としてのドラムミキサーの他に、ディスクペレタイザーを単独でまたはドラムミキサーと併用して用いることもできる。
<Other suitable operating conditions>
In the method for producing sintered ore of the present invention, a disk pelletizer can be used alone or in combination with a drum mixer, in addition to the drum mixer as a granulating apparatus in the above-described embodiments.
また、造粒装置の造粒においては、処理した原料に対して石灰石を被覆して、その造粒粒子の表面に固体系燃料を被覆するいわゆる外装をすることが好ましい。外装をすると好ましいのは、石灰石を外装化することで表面に強度の高いカルシウムフェライトを生成させためであり、固体系燃料の疎水性のため造粒性への悪影響を及ぼすため表面に付着させることで抑制させ、造粒粒子径を増加させて生産性を高めるためである。 In the granulation of the granulator, it is preferable to coat the raw material that has been treated with limestone and to coat the surface of the granulated particles with a solid fuel. It is preferable to make the exterior to make calcium ferrite with high strength on the surface by making limestone exterior, and to adhere to the surface because it has a negative effect on granulation due to the hydrophobic nature of the solid fuel. This is because the productivity is improved by increasing the granulated particle diameter.
さらに、焼結原料としては、少なくとも１種類以上は結晶水鉱石を含み、結晶水の含有量を４ｍａｓｓ%以上としたものを使用することが好ましい。結晶水の含有量を４ｍａｓｓ％以上とするのが好ましいのは、結晶水が高い鉱石は比表面積が高く、微粉鉱石の造粒性を向上させることができるためである。さらにまた、１２５μｍ以下の微粉鉄鉱石に石灰石を５ｍａｓｓ％以上含むことが好ましい。石灰石を５ｍａｓｓ％以上含むことが好ましいのは、微細な石灰石を含むことで、微粉鉱石と石灰石との混合性を向上させることができ、焼結反応の促進が可能である。 Furthermore, as the sintering raw material, it is preferable to use one containing at least one kind of crystal water ore and a crystal water content of 4 mass% or more. The reason why the content of crystallization water is preferably 4 mass% or more is because an ore having a high crystallization water has a high specific surface area and can improve the granulation property of fine ore. Furthermore, it is preferable that 5 mass% or more of limestone is contained in the fine iron ore of 125 μm or less. It is preferable that 5 mass% or more of limestone is contained. By containing fine limestone, the mixing property of fine ore and limestone can be improved, and the sintering reaction can be promoted.
また、高速撹拌機で処理する焼結原料には、被覆する石灰分以外に、消石灰もしくは生石灰を３ｍａｓｓ％以下添加することが好ましい。消石灰もしくは生石灰を３ｍａｓｓ％以下添加するのが好ましいのは、消石灰もしくは生石灰の添加は、造粒粒子の圧壊強度を向上させて焼結原料充填層での通気性を向上させることができるためである。さらに、前記高速撹拌機に使用する焼結原料において、微粉鉄鉱石の割合が３０ｍａｓｓ％以上においては焼結原料を乾燥処理することが好ましい。３０ｍａｓｓ％以上で乾燥処理するのが好ましいのは、焼結過程における水分は蒸発させるための潜熱が必要であり、事前に乾燥させることで必要な粉コークス等の炭材を低減させることができるためである。 Moreover, it is preferable to add 3 mass% or less of slaked lime or quicklime to the sintering raw material processed with a high-speed stirrer in addition to the lime content to coat. It is preferable to add slaked lime or quicklime to 3 mass% or less because the addition of slaked lime or quicklime can improve the crushing strength of the granulated particles and improve the air permeability in the sintered raw material packed layer. . Furthermore, in the sintering raw material used for the high-speed stirrer, it is preferable that the sintering raw material is subjected to a drying treatment when the proportion of fine iron ore is 30 mass% or more. It is preferable to perform the drying process at 30 mass% or more because the moisture in the sintering process needs latent heat to evaporate, and the carbonaceous materials such as powdered coke can be reduced by drying in advance. It is.
本発明の焼結鉱の製造方法によれば、種々の焼結機を用いて高い生産性で高品位の焼結鉱を製造することができ、高炉原料として本発明で得られた焼結鉱を利用することで、高い生産性の高炉操業を行うことが可能となる。
According to the method for producing sintered ore of the present invention, high-quality sintered ore can be produced with high productivity using various sintering machines, and the sintered ore obtained in the present invention as a blast furnace raw material. By using this, it becomes possible to perform blast furnace operation with high productivity.
本発明は、焼結原料について造粒後ＤＬ式焼結機などを用いて製造される、高炉原料としての焼結鉱の製造方法に関する。 The present invention relates to a method for producing sintered ore as a blast furnace raw material, which is produced by using a DL-type sintering machine after granulation for a sintered raw material.
焼結鉱は、複数銘柄の粉鉄鉱石（一般に、１２５〜１０００μｍ程度のシンターフィードと呼ばれているもの）に、石灰石や珪石、蛇紋岩等の副原料粉と、ダスト、スケール、返鉱等の雑原料粉と、粉コークス等の固体燃料とを適量ずつ配合した焼結配合原料に、水分を添加して混合−造粒し、得られた造粒原料を焼結機に装入して焼成することによって製造される。その焼結配合原料は、一般に、水分を含むことで造粒時に互いに凝集して擬似粒子となる。そして、この擬似粒子化した焼結用造粒原料は、焼結機のパレット上に装入されたとき、焼結原料装入層の良好な通気を確保するのに役立ち、焼結反応を円滑に進める。 Sintered ore consists of several brands of fine iron ore (generally called sinter feed of about 125 to 1000 μm), auxiliary raw material powders such as limestone, quartzite, and serpentine, and dust, scale, return ore, etc. The raw material powder and solid fuel such as powdered coke are mixed in an appropriate amount to add the moisture, mix and granulate, and charge the resulting granulated material into the sintering machine. Manufactured by firing. Generally, the sintered blending raw material contains moisture, and aggregates into pseudo particles during granulation. This pseudo-granulated raw material for sintering, when placed on the pallet of the sintering machine, helps to ensure good ventilation of the sintered raw material charging layer and facilitates the sintering reaction. Proceed to
ところで、焼結用粉鉄鉱石は、近年、高品質鉄鉱石の枯渇によって低品位化している。即ち、鉄鉱石の低品位化は、スラグ成分の増加や微粉化の傾向を招き、そのためにアルミナ含有量の増大や微粉比率の増大による造粒性を低下させる。その一方で、高炉で使用する焼結鉱としては、高炉での溶銑製造コストの低減やＣＯ２発生量の低減という観点から低スラグ比、高被還元性、高強度のものが求められている。 By the way, in recent years, powder iron ore for sintering has been lowered in quality by depletion of high-quality iron ore. That is, the lower grade of iron ore leads to an increase in slag components and a tendency to pulverization, and therefore the granulation properties are decreased due to an increase in the alumina content and an increase in the pulverization ratio. On the other hand, sintered ore used in the blast furnace is required to have a low slag ratio, high reducibility, and high strength from the viewpoint of reducing hot metal production cost in the blast furnace and reducing CO 2 generation amount. .
焼結用粉鉄鉱石を取り巻くこのような環境の中で、最近、ペレットフィードと呼ばれるペレット用として用いられてきた難造粒性の微粉鉄鉱石を使って、高品質の焼結鉱を製造するための技術が提案されている。例えば、こうした従来技術の１つに、Hybrid Pelletized Sinter法（以下、「ＨＰＳ法」という）がある。この技術は、ペレットフィードのような微粉鉄鉱石を多量に含む焼結配合原料をドラムミキサーとペレタイザーとを使って造粒することにより、低スラグ比・高被還元性の焼結鉱を製造しようというものである（特許文献１、特許文献２、特許文献３、特許文献４、特許文献５）。
In such an environment surrounding powdered iron ore for sintering, high-quality sintered ore is produced using the hardly granulated fine iron ore that has been used for pellets recently called pellet feed. Techniques for this have been proposed. For example, one such conventional technique is the Hybrid Pelletized Sinter method (hereinafter referred to as “HPS method”). In this technology, low-slag-ratio, highly-reducible sintered ore is produced by granulating a sintering compounded raw material containing a large amount of fine iron ore such as pellet feed using a drum mixer and pelletizer. (
その他、焼結原料粉造粒工程の前に、高速回転ミキサーにて調湿混合する方法（特許文献６）や、造粒工程の前に、微粉鉄鉱石と製鉄ダストとを撹拌混合機で予め混合する方法（特許文献７）、微粉（ペレットフィード）をアイリッヒミキサーで予め混合処理したのちドラムミキサーにて造粒する方法（特許文献８）、粒径２５０μｍ以下の粒子を６０重量％以上含む鉄鉱石原料を混練後、ドラムミキサーで造粒する方法（特許文献９）などの提案もある。 In addition, prior to the sintering raw material powder granulation step, a method of conditioning and mixing with a high-speed rotary mixer (Patent Document 6), and before the granulation step, fine iron ore and iron dust are preliminarily mixed with a stirring mixer. A method of mixing (Patent Document 7), a method of premixing fine powder (pellet feed) with an Eirich mixer and then granulating with a drum mixer (Patent Document 8), containing 60% by weight or more of particles having a particle size of 250 μm or less There is also a proposal such as a method (Patent Document 9) in which an iron ore raw material is kneaded and then granulated with a drum mixer.
しかしながら、ペレットフィードなどの微粉鉄鉱石、とくに超微粉鉄鉱石を多量に含む焼結配合原料は、これを前記特許文献１〜５に記載されているようなＨＰＳ法を用いて造粒したり、前記特許文献６〜９に記載されているような高速撹拌機などを使って予め混合処理したりする方法では、次のような問題がある。
However, the sintered blending raw material containing a large amount of fine iron ore, particularly ultra fine iron ore, such as pellet feed, is granulated using the HPS method as described in
すなわち、図１に示すように、これらの方法では、細粒（０．５ｍｍ未満）のみならず、粗大（１０ｍｍ超）な擬似粒子が多く生成する。その理由は、ペレットフィードのような微粉鉄鉱石は、濡れ性が同じであれば、細粒ほど比表面積が大きいので水分を吸収しやすく、かつ粉体間に多くの水分を保持しやすいため、個々の微粉鉄鉱石が水分を優先的に吸収しやすくなるからである。その結果、微粉どうしが単に凝集しただけにすぎないものや、核粒子のまわりに微粉が付着した形態の粒径の不揃いな粗大な擬似粒子が生成しやすくなるのである。さらに、これらの方法では粉体の付着の問題や、微粉や水分の均一分散が悪く、かつ設備稼働率の低下を招くという問題もある。 That is, as shown in FIG. 1, in these methods, not only fine particles (less than 0.5 mm) but also large (greater than 10 mm) pseudo particles are generated. The reason is that fine iron ore like pellet feed, if the wettability is the same, the finer the specific surface area, the greater the specific surface area, so it is easy to absorb moisture and hold more moisture between the powders. It is because each fine iron ore becomes easy to absorb moisture preferentially. As a result, it is easy to generate coarse pseudo particles in which the fine particles are simply aggregated or coarse particles having irregular particle sizes in a form in which the fine particles adhere around the core particles. Furthermore, these methods also have problems of adhesion of powder, poor uniform dispersion of fine powder and moisture, and a decrease in equipment operation rate.
この点に関しては、発明者らが行なった下記の実験からも明らかである。まず、この実験では、ペレットフィードなどの難造粒性の微粉鉄鉱石（バナジウム含有量：４０ｍａｓｓ％）を含有する配合原料を使用して造粒し、この時、生成した造粒粒子（擬似粒子）の粒度分布とペレットフィードの粒度分布を計測した。その結果を図２に示す。まず、図２（ａ）に示すように、焼結配合原料中にペレットフィードを多量に含むものは、ペレットフィードを含まないものに比べると、粗粒（８ｍｍ超）になる割合が高くなった。その重量割合は７５ｍａｓｓ％程度に達した。また、造粒した疑似粒子中のペレットフィードの粒度分布（図２（ｂ））は、造粒粒子の粒度分布（図２（ａ））と同様の傾向を示した。即ち、粗粒中のペレットフィードは、その割合が８０ｍａｓｓ％程度と高く、ペレットフィードの殆どが該粗粒中に偏在することがわかった。このことから、粗大な擬似粒子というのは、ペレットフィードどうしが凝集し合うことで形成されていることが分る。そして、粗粒領域に属するこの擬似粒子は、また、水分量も高いということが分った（図２（ｂ））。このことから、水分はペレットフィードが優先して吸収し、そのためにペレットフィードどうしが凝集し合って粗大な擬似粒子を形成し、その結果、粗大な疑似粒子中には多くの水分が吸収されることになる。 This point is also clear from the following experiment conducted by the inventors. First, in this experiment, granulation was performed using a blended raw material containing finely granulated iron ore (vanadium content: 40 mass%) such as pellet feed, and at this time, the generated granulated particles (pseudo particles) ) And the particle size distribution of the pellet feed. The result is shown in FIG. First, as shown in FIG. 2 (a), those containing a large amount of pellet feed in the sintered blending material have a higher proportion of coarse particles (over 8 mm) than those containing no pellet feed. . The weight ratio reached about 75 mass%. In addition, the particle size distribution of the pellet feed in the granulated pseudo particles (FIG. 2B) showed the same tendency as the particle size distribution of the granulated particles (FIG. 2A). That is, the ratio of the pellet feed in the coarse grains was as high as about 80 mass%, and it was found that most of the pellet feed was unevenly distributed in the coarse grains. From this, it can be seen that coarse pseudo-particles are formed by aggregation of pellet feeds. And it turned out that this pseudo particle which belongs to a coarse-grain area | region also has a high moisture content (FIG.2 (b)). Therefore, the pellet feed is preferentially absorbed by the pellet feed, and therefore the pellet feeds aggregate to form coarse pseudo particles, and as a result, a large amount of moisture is absorbed in the coarse pseudo particles. It will be.
このようにペレットフィード等の微粉鉄鉱石を多く含む配合原料は、これを造粒すると、どうしても粒径が不揃いになると共に、微粉どうしが単に凝集したにすぎないものとなって、結合強度の弱い粗大な擬似粒子を生成しやすくなる。そのため、このような疑似粒子を焼結機のパレット上に装入して堆積させると、図３（ａ）に示すように、焼結原料装入層は密な堆積構造となって、かさ密度が大きくなる。しかも、このような粗大な擬似粒子は、焼結機のパレット上に一定の層厚で堆積させると、該擬似粒子に荷重（圧縮力）が加わったときに壊われやすくなるため、粉化して空隙率の低下を招き、ひいては通気性の悪化を招いて焼結機操業の阻害要因になる。その結果として、焼結時間が長くなり、焼結鉱の歩留低下を招いて生産性が低下するおそれがある。さらには、造粒に用いられるバインダーである生石灰の使用量を増加せざるを得なくなり、焼結鉱製造コストの増大を招き、後工程において粉コークス等の固体燃料を被覆する際に、焼結原料全体としての粉コークス等の賦存状態の不均一を招くようになる。その結果、燃焼や着熱不良を招いて焼成速度を低下させる。 In this way, the blended raw material containing a large amount of fine iron ore such as pellet feed, when granulated, inevitably becomes uneven in particle size, and the fine powder is merely agglomerated, and the bond strength is weak. Coarse pseudo particles are easily generated. Therefore, when such pseudo particles are charged and deposited on the pallet of the sintering machine, as shown in FIG. 3 (a), the sintered raw material charging layer has a dense deposition structure and a bulk density. Becomes larger. Moreover, if such coarse pseudo-particles are deposited on a pallet of a sintering machine with a certain layer thickness, they are easily broken when a load (compressive force) is applied to the pseudo-particles. This leads to a decrease in porosity, which in turn causes deterioration in air permeability, which becomes an impediment to sintering machine operation. As a result, the sintering time becomes longer, and the yield of sintered ore may be reduced, leading to a decrease in productivity. Furthermore, the amount of quicklime, which is a binder used for granulation, must be increased, resulting in an increase in the production cost of sintered ore, and sintering when coating solid fuel such as powdered coke in the subsequent process. As a result, non-uniformity of the existing state of the powdered coke and the like as the whole raw material is caused. As a result, combustion and poor heat receiving are caused and the firing rate is lowered.
本発明の目的は、微粉鉄鉱石を焼結鉱製造用配合原料として使用する場合において、適正な擬似粒子を造粒して、焼結機での生産性を向上させることができる焼結鉱の製造方法を提案することにある。 The object of the present invention is to use a fine ore as a raw material for the production of sintered ore, granulate appropriate pseudo particles, and improve the productivity of the sintered ore. It is to propose a manufacturing method.
前述した従来技術が抱えている課題について鋭意検討を重ねた結果、発明者らは、所定の粒度の微粉の所定量を有する焼結原料を高速撹拌装置による事前処理することで、その後の造粒時に、粒径が不揃いで結合強度の弱い粗大な造粒粒子（擬似粒子）が発生するのを阻止でき、適正な擬似粒子を造粒して、焼結機での生産性を向上させることができることを突き止めて、本発明を開発した。 As a result of intensive investigations on the problems of the prior art described above, the inventors have previously processed a granulated raw material having a predetermined amount of fine powder having a predetermined particle size by a high-speed agitator, and thereafter granulated. Sometimes it is possible to prevent the generation of coarse granulated particles (pseudo particles) with uneven particle size and weak bond strength, and to improve the productivity in the sintering machine by granulating appropriate pseudo particles. The present invention was developed after finding out what can be done.
即ち、本発明は、焼結原料を造粒後焼結機で焼結して焼結鉱を得る焼結鉱の製造方法において、１２５μｍ以下の微粉鉄鉱石を１０〜５０ｍａｓｓ％含む焼結原料の事前処理を高速撹拌装置で行った後、造粒装置で造粒を行うことを特徴とする焼結鉱の製造方法にある。 That is, the present invention relates to a method for producing sintered ore in which a sintered raw material is obtained by granulating a sintered raw material after sintering with a sintering machine, and containing 10 to 50 mass% of fine iron ore of 125 μm or less. In the method for producing a sintered ore, the pretreatment is performed with a high-speed agitator and then granulated with a granulator.
なお、前記のように構成される本発明に係る焼結鉱の製造方法においては、
（１）前記高速撹拌装置の羽根の周速Ｕ（ｍ／ｓ）に対して、前記高速撹拌装置による撹拌時間ｔ（秒）とした場合に、３００＜Ｕ×ｔ＜２０００の条件を満たすように事前処理を行うこと、
（２）前記高速撹拌装置の羽根の周速Ｕ（ｍ／ｓ）に対して、前記高速撹拌装置による撹拌時間ｔ（秒）とした場合に、４００＜Ｕ×ｔ＜１２００の条件を満たすように事前処理を行うこと、
（３）前記造粒装置は、ドラムミキサーおよび／またはディスクペレタイザーであること、
（４）前記造粒装置の造粒においては、処理した原料に対して石灰石を被覆して、その造粒粒子の表面に固体系燃料を被覆すること、
（５）前記焼結原料としては、少なくとも１種類以上は結晶水鉱石を含み、結晶水の含有量を４ｍａｓｓ%以上としたこと、
（６）前記１２５μｍ以下の微粉鉄鉱石に石灰石を５ｍａｓｓ％以上含むこと、
（７）前記高速撹拌機で処理する焼結原料には、被覆する石灰分以外に、消石灰もしくは生石灰を３ｍａｓｓ％以下添加すること、
（８）前記高速撹拌機に使用する焼結原料において、微粉鉄鉱石の割合が３０ｍａｓｓ％以上においては原料を乾燥処理すること、
がより好ましい解決手段となるものと考えられる。
In the method of manufacturing a sintered ore according to the present invention configured as described above,
(1) With respect to the peripheral speed U (m / s) of the blades of the high-speed stirring device, when the stirring time t (seconds) by the high-speed stirring device is used, the condition of 300 <U × t <2000 is satisfied. Pre-processing,
(2) The condition of 400 <U × t <1200 is satisfied when the stirring time t (seconds) by the high-speed stirrer is set with respect to the peripheral speed U (m / s) of the blades of the high-speed stirrer. Pre-processing,
(3) the granulator is a drum mixer and / or a disk pelletizer;
(4) In the granulation of the granulator, the treated raw material is coated with limestone, and the surface of the granulated particles is coated with a solid fuel,
(5) As the sintering raw material, at least one kind contains crystal water ore, and the content of crystal water is 4 mass% or more,
(6) containing 5 mass% or more of limestone in the fine iron ore of 125 μm or less,
(7) In addition to the lime content to be coated, slaked lime or quicklime is added in an amount of 3 mass% or less to the sintered raw material to be processed with the high-speed stirrer.
(8) In the sintering raw material used for the high-speed stirrer, when the proportion of fine iron ore is 30 mass% or more, the raw material is dried.
Is considered to be a more preferable solution.
本発明は、微粉鉄鉱石と細粒とが強固に凝集したもの、または核粒子のまわりに微粉鉄鉱石等が付着した構造の、粒径が比較的揃って粒度分布が小さい擬似粒子からなる焼結用造粒原料の製造方法を提案するものである。こうした方法によって得られた焼結用造粒原料は、これを焼結機のパレット上に装入したとき、パレット上に形成される焼結原料装入層の密度の低減や、通気性の向上に伴う焼成時間の短縮を図ることができ、ひいては高品質焼結鉱の生産性を向上させるのに有効である。 In the present invention, fine iron ore and fine particles are agglomerated firmly, or a structure in which fine iron ore or the like is adhered around the core particles is a sintered particle composed of pseudo particles having a relatively uniform particle size and a small particle size distribution. The manufacturing method of the granulation raw material for ligation is proposed. When the granulated raw material for sintering obtained by such a method is placed on a pallet of a sintering machine, the density of the sintered raw material charging layer formed on the pallet is reduced and the air permeability is improved. Thus, the firing time can be shortened, which is effective in improving the productivity of high-quality sintered ore.
＜本発明の特徴事項である造粒前の事前処理について＞
図４は、本発明の焼結鉱の製造方法を実施する設備列の一例を説明するための図である。図４に従って本発明の焼結鉱の製造方法を説明すると、まず、１２５μｍ以下の微粉鉄鉱石を１０〜５０ｍａｓｓ％含む焼結原料１１を準備する。焼結原料１１は、上述した１０〜５０ｍａｓｓ％の１２５μｍ以下のペレットフィードやテーリング鉱である微粉鉄鉱石と、残部がシンダーフィードである粉鉄鉱石の他、返鉱、珪石、石灰、生石灰などのその他の原料と、からなることが好ましい。なお、本発明において、焼結原料１１として、１２５μｍ以下の微粉鉄鉱石を１０〜５０ｍａｓｓ％含むものに限定した理由は、以下の通りである。
<About pretreatment before granulation which is a feature of the present invention>
FIG. 4 is a diagram for explaining an example of an equipment row for carrying out the method for producing a sintered ore according to the present invention. The method for producing a sintered ore according to the present invention will be described with reference to FIG. 4. First, a sintering
すなわち、上記微粉鉄鉱石の発明範囲は粒径が不揃いで結合強度が弱い粗大な粒子が出来るために設定したものであり、１０％未満では結合強度の弱い擬似粒子が出来ない等、また５０％超えでは同様に結合強度が弱い粗大な粒子が出来る問題があるが、実質的に１２５μｍ以下の微粉鉄鉱石を５０ｍａｓｓ％超えて配合することはなく上限を５０％とした。粒径を１２５μｍ以下とした理由は、粒径１２５μｍ以下においては、水分を添加した粉体充填層における粒子層同士の接着性を表す付着力が増加するために造粒性が大きく異なる挙動を示したため、１２５μｍを粒度の区間に設定した。 That is, the invention range of the fine iron ore is set to produce coarse particles with irregular particle sizes and weak bond strength. If it is less than 10%, pseudo particles with low bond strength cannot be formed, and 50%. If exceeding the above, there is a problem that coarse particles having a weak bond strength can be formed in the same manner. However, the upper limit is set to 50% without adding more than 50 mass% of fine iron ore of 125 μm or less. The reason why the particle size is set to 125 μm or less is that when the particle size is 125 μm or less, the adhesion force representing the adhesion between the particle layers in the powder-filled layer to which moisture has been added increases, and thus the granulation property is greatly different. Therefore, 125 μm was set as the particle size section.
次に、準備した焼結原料１１の事前処理を高速撹拌機１２で実施する。高速撹拌機１２の目的は、粗大な造粒粒子の生成を抑止するために、粗大な造粒粒子の種となる微粉の凝集体を造粒前に壊砕することにある。微粉の凝集体を効率的に壊砕するためには、ミクロ的には、凝集体自身に、せん断力を加えて、直接微粉を剥離させることが有効である。高速撹拌機１２の一例としては、たとえば、アイリッヒミキサー(日本アイリッヒ製)、ペレガイアミキサー（北川鉄工製）、プロシェアミキサー(太平洋機工)などを用いることができる。このうちアイリッヒミキサーは、「高速撹拌造粒」機として知られ、液体架橋による粒子の凝集、成長に伴う造粒機能を併せもつ設備である。
Next, pretreatment of the prepared sintered
次に、事前処理を高速撹拌機１２で行われた焼結原料１１を、ドラムミキサー１３によって、水分添加の下で撹拌混合して造粒する。造粒後の焼結原料１１は焼結機１４に供給され、焼結機１４において焼結鉱となる。そして、焼結鉱は、コークス、石灰石などとともに高炉原料として高炉１５に供給されて銑鉄を製造する。
Next, the sintered
本発明の特徴となる、造粒前の事前処理の影響を調べるため、１２５μｍの微粉鉄鉱石を３０ｍａｓｓ％含む同じ焼結原料に対し、図５に示すように、高速撹拌ミキサー（アイリッヒミキサー）とドラムミキサーとにより、造粒前の事前処理を実施した。それぞれのミキサーによる混合時間を０〜１６０秒間で変化させ、事前処理後ドラムミキサーで１６０秒間造粒を行った後の焼結原料に対し粒度分布を求め、それに基づき以下の式で定義されるＩｓ、Ｉｐを求め、それぞれの調和平均径Ｄｐ（ｍｍ）、粒度分布関数Ｉｓｐ、さらには、焼結前充填層の相対通過風量を図６、図７および図８に示す。なお、いずれの例においても、ドラムミキサーによる事前処理が０秒の例が従来例となる。高速撹拌ミキサーに使用により調和平均径が増加して、粒度分布関数Ｉｓｐによる粒度分布がシャープになる効果が得られた。相対通貨風量量についても増加効果が得られた。ここで、相対通過風量が大きいほど値ほど、一定負圧で操業する焼結機においてガス量が大きくすることができ、生産性が高くなる。 In order to investigate the influence of pretreatment before granulation, which is a feature of the present invention, as shown in FIG. 5, a high-speed stirring mixer (Eirich mixer) is used for the same sintered raw material containing 30 mass% of 125 μm fine iron ore. And a drum mixer were used for pretreatment before granulation. The mixing time by each mixer is changed from 0 to 160 seconds, the particle size distribution is obtained for the sintered raw material after granulation for 160 seconds by the drum mixer after the pretreatment, and Is defined by the following formula based on it. , Ip, and the harmonic mean diameter Dp (mm), the particle size distribution function Isp, and the relative passing air volume of the packed bed before sintering are shown in FIG. 6, FIG. 7, and FIG. In any of the examples, an example in which the pre-processing by the drum mixer is 0 seconds is a conventional example. The harmonic average diameter was increased by using it in a high-speed stirring mixer, and the effect of sharpening the particle size distribution by the particle size distribution function Isp was obtained. The effect of increasing relative currency volume was also obtained. Here, the larger the relative passing air volume, the larger the value, the higher the gas volume in the sintering machine operating at a constant negative pressure, and the higher the productivity.
Ｄｐ＝１／Σ（ｗｉ／ｄｉ）
Ｉｓｐ＝１００√（Ｉｓ×Ｉｐ）
Ｉｓ＝Ｄｐ２Σｗｉ（１／ｄｉ−１／Ｄｐ）２
Ｉｐ＝（１／Ｄｐ）２Σｗｉ（ｄｉ−Ｄｐ）２
ここで、
Ｄｐ：調和平均径（ｍｍ）
ｗｉ：区間における重量存在率（−）
ｄｉ：区間の代表平均径（ｍｍ）
Ｉｓｐ：粒度分布関数
Ｉｓ：細粒における粒度分布関数（−）
Ｉｐ：粗粒における粒度分布関数（−）
Dp = 1 / Σ (wi / di)
Isp = 100√ (Is × Ip)
Is = Dp 2 Σwi (1 / di−1 / Dp) 2
Ip = (1 / Dp) 2 Σwi (di−Dp) 2
here,
Dp: harmonic mean diameter (mm)
wi: Weight abundance ratio in the section (−)
di: Typical average diameter of the section (mm)
Isp: particle size distribution function Is: particle size distribution function in fine particles (-)
Ip: Particle size distribution function (−) in coarse particles
図６、図７および図８の結果から、造粒前の事前処理を高速撹拌ミキサーで実施した本発明例は、事前処理を行わなかった従来例および造粒前の事前処理をドラムミキサーで実施した比較例に比べて、高い調和平均径（図６）、低い粒度分布関数(図７)および高い焼結前充填層の相対通過風量（図８）を得ることができ、良好な性状の焼結原料が得られることがわかった。 From the results of FIGS. 6, 7 and 8, the example of the present invention in which the pretreatment before granulation was performed with a high-speed stirring mixer was performed in the conventional example in which the pretreatment was not performed and the pretreatment before granulation was performed with a drum mixer. Compared with the comparative example, a high harmonic mean diameter (Fig. 6), a low particle size distribution function (Fig. 7) and a high relative passing air volume (Fig. 8) of the packed bed before sintering can be obtained. It was found that a ligation raw material was obtained.
＜高速撹拌機の好適な操業条件について＞
本発明の焼結鉱の製造方法における高速撹拌機の好適な操業条件を調べるため、１２５μｍの微粉鉄鉱石を３０ｍａｓｓ％含む同じ焼結原料に対し、高速撹拌機の高速で回転する羽根の周速Ｕ（ｍ／ｓ）と撹拌時間ｔ（秒）との関係に着目した。そして、周速ＵをＵ＝９ｍ／ｓの条件に固定して撹拌時間ｔをｔ＝０〜２４０秒の範囲で変えた例と、撹拌時間ｔをｔ＝１２０秒の条件に固定して周速ＵをＵ＝０〜１８ｍ／ｓの範囲で変えた例と、周速ＵをＵ＝６ｍ／ｓの条件に固定して撹拌時間を０〜２４０秒の範囲で変えた例と、について、造粒後焼結機で焼結して得た焼結鉱の生産率を求めるとともに、（Ｕ×ｔ）で整理した。
<Suitable operating conditions for high-speed agitator>
In order to investigate suitable operating conditions of the high-speed stirrer in the method for producing sintered ore of the present invention, the peripheral speed of the blade rotating at a high speed of the high-speed stirrer with respect to the same sintered raw material containing 30 mass% of 125 μm fine iron ore Attention was paid to the relationship between U (m / s) and stirring time t (seconds). The example in which the circumferential speed U is fixed to the condition of U = 9 m / s and the stirring time t is changed in the range of t = 0 to 240 seconds, and the stirring time t is fixed to the condition of t = 120 seconds and the circumferential speed U is fixed. Regarding an example in which the speed U is changed in the range of U = 0 to 18 m / s, and an example in which the peripheral speed U is fixed to the condition of U = 6 m / s and the stirring time is changed in the range of 0 to 240 seconds. After the granulation, the production rate of the sintered ore obtained by sintering with a sintering machine was obtained, and the production rate was arranged by (U × t).
ここで、粒径が不揃いで結合強度の弱い粗大な造粒粒子（擬似粒子）が発生するのを阻止でき、適正な擬似粒子を造粒することができる条件として、周速Ｕに撹拌時間ｔを乗じたＵ×ｔについて着目した。Ｕ×ｔの次元としては長さ「ｍ」の次元を持った物理量を持っており、高速で回転する羽根により与えられた移動距離と考えられるため、異なる周速および撹拌時間により整理できると考えた。高速撹拌機において、上部より投入された原料が下部へ流れ出る構造であることから、装置内の原料の占有率が一定の場合、投入速度が変更された場合に撹拌時間が変化する。その際、適切な範囲Ｕ×ｔを定めることで安定した品質の焼結鉱が製造可能になることがわかる。 Here, as a condition for preventing generation of coarse granulated particles (pseudoparticles) having uneven particle sizes and weak bond strength, it is possible to granulate appropriate pseudoparticles at a circumferential speed U at a stirring time t. We focused on U x t multiplied by. The dimension of U × t has a physical quantity with a dimension of “m” in length, and is considered to be a moving distance given by a blade rotating at high speed. Therefore, it can be arranged by different peripheral speeds and stirring times. It was. In the high-speed stirrer, since the raw material charged from the upper part flows out to the lower part, the stirring time changes when the raw material occupancy in the apparatus is constant or the charging speed is changed. At that time, it can be seen that stable sintered ore quality by determining an appropriate range U × t becomes possible to produce.
周速ＵをＵ＝９ｍ／ｓの条件に固定して撹拌時間ｔをｔ＝０〜２４０秒の範囲で変えた場合の生産率（ｔ／ｈｒ／ｍ２）と（Ｕ×ｔ）との関係を図９及び以下の表１に示し、撹拌時間ｔをｔ＝１２０秒の条件に固定して周速ＵをＵ＝０〜１８ｍ／ｓの範囲で変えた場合の生産率（ｔ／ｈｒ／ｍ２）と（Ｕ×ｔ）との関係を図１０及び以下の表２に示し、周速ＵをＵ＝６ｍ／ｓの条件に固定して撹拌時間ｔをｔ＝０〜２４０秒の範囲で変えた場合の生産率（ｔ／ｈｒ／ｍ２）と（Ｕ×ｔ）との関係を図１１及び以下の表３に示す。 The production rate (t / hr / m 2 ) and (U × t) when the circumferential speed U is fixed to U = 9 m / s and the stirring time t is changed in the range of t = 0 to 240 seconds. 9 and Table 1 below, the production rate (t / hr) when the stirring time t is fixed at t = 120 seconds and the peripheral speed U is changed in the range of U = 0 to 18 m / s. / M 2 ) and (U × t) are shown in FIG. 10 and Table 2 below, and the circumferential speed U is fixed at U = 6 m / s and the stirring time t is t = 0 to 240 seconds. The relationship between the production rate (t / hr / m 2 ) and (U × t) when changed in the range is shown in FIG. 11 and Table 3 below.
図９〜図１１（表１〜表３のデータに基づく）の結果から、Ｕ＜８ｍ／ｓとＵ≧８ｍ／ｓの２条件ついて（Ｕ×ｔ）と生産率との関係を求め、図１２に散布図として示す。図１２の結果から、いずれの例において、Ｕ×ｔを３００＜Ｕ×ｔ＜２０００の条件を満たすように高速撹拌機により事前処理を行うことが好ましく、Ｕ×ｔを４００＜Ｕ×ｔ＜１２００の条件を満たすように高速撹拌機により事前処理を行うことが更に好ましいことがわかる。いずれの例においてもＵ×ｔの好適範囲がほぼ同じであることから、上記Ｕ×ｔの範囲は、高速撹拌機の周速および撹拌時間の種々の例についても好適例として一般化できることがわかる。 From the results of FIGS. 9 to 11 (based on the data in Tables 1 to 3), the relationship between (U × t) and the production rate is obtained for two conditions of U <8 m / s and U ≧ 8 m / s. 12 shows a scatter diagram. From the results of FIG. 12, in each of the examples, it is preferable to perform the pre-processing by a high-speed stirrer to meet U × t a 300 <U × t <2000 conditions, 400 U × t <U × t < It can be seen that it is more preferable to perform pretreatment with a high-speed stirrer so as to satisfy the condition of 1200. Since the preferable range of U × t is almost the same in any of the examples, it can be understood that the range of U × t can be generalized as a preferable example for various examples of the peripheral speed and the stirring time of the high-speed stirrer. .
また、図９の結果から、高速撹拌装置で行う焼結原料の事前処理において、高速撹拌装置の高速で回転する羽根の周速Ｕを９（ｍ／ｓ）としたとき、高速撹拌装置の撹拌時間を３０秒以上とすることが好ましいことがわかる。さらに、図１０の結果から、高速撹拌装置の撹拌時間を１２０秒としたとき、高速撹拌装置の高速で回転する羽根の周速Ｕ（ｍ／ｓ）を６≦Ｕ≦１２とすることが好ましいことがわかる。さらにまた、図１１の結果から、高速撹拌装置で行う焼結原料の事前処理において、高速撹拌装置の高速で回転する羽根の周速Ｕを６（ｍ／ｓ）としたとき、高速撹拌装置の撹拌時間を６０秒以上とすることが好ましいことがわかる。 Moreover, from the result of FIG. 9, in the pre-processing of the sintering raw material performed by the high-speed stirring device, when the peripheral speed U of the blade rotating at high speed of the high-speed stirring device is 9 (m / s), the stirring of the high-speed stirring device It can be seen that the time is preferably 30 seconds or more. Furthermore, from the result of FIG. 10, when the stirring time of the high-speed stirring device is 120 seconds, it is preferable that the peripheral speed U (m / s) of the blade rotating at high speed of the high-speed stirring device is 6 ≦ U ≦ 12. I understand that. Furthermore, from the result of FIG. 11, when the peripheral speed U of the blade rotating at high speed of the high-speed stirrer is 6 (m / s) in the pretreatment of the sintering raw material performed by the high-speed stirrer, It can be seen that the stirring time is preferably 60 seconds or more.
＜その他の好適な操業条件について＞
本発明の焼結鉱の製造方法では、上述した実施例における造粒装置としてのドラムミキサーの他に、ディスクペレタイザーを単独でまたはドラムミキサーと併用して用いることもできる。
<Other suitable operating conditions>
In the method for producing sintered ore of the present invention, a disk pelletizer can be used alone or in combination with a drum mixer, in addition to the drum mixer as a granulating apparatus in the above-described embodiments.
また、造粒装置の造粒においては、処理した原料に対して石灰石を被覆して、その造粒粒子の表面に固体系燃料を被覆するいわゆる外装をすることが好ましい。外装をすると好ましいのは、石灰石を外装化することで表面に強度の高いカルシウムフェライトを生成させためであり、固体系燃料の疎水性のため造粒性への悪影響を及ぼすため表面に付着させることで抑制させ、造粒粒子径を増加させて生産性を高めるためである。 In the granulation of the granulator, it is preferable to coat the raw material that has been treated with limestone and to coat the surface of the granulated particles with a solid fuel. It is preferable to make the exterior to make calcium ferrite with high strength on the surface by making limestone exterior, and to adhere to the surface because it has a negative effect on granulation due to the hydrophobic nature of the solid fuel. This is because the productivity is improved by increasing the granulated particle diameter.
さらに、焼結原料としては、少なくとも１種類以上は結晶水鉱石を含み、結晶水の含有量を４ｍａｓｓ%以上としたものを使用することが好ましい。結晶水の含有量を４ｍａｓｓ％以上とするのが好ましいのは、結晶水が高い鉱石は比表面積が高く、微粉鉱石の造粒性を向上させることができるためである。さらにまた、１２５μｍ以下の微粉鉄鉱石に石灰石を５ｍａｓｓ％以上含むことが好ましい。石灰石を５ｍａｓｓ％以上含むことが好ましいのは、微細な石灰石を含むことで、微粉鉱石と石灰石との混合性を向上させることができ、焼結反応の促進が可能である。 Furthermore, as the sintering raw material, it is preferable to use one containing at least one kind of crystal water ore and a crystal water content of 4 mass% or more. The reason why the content of crystallization water is preferably 4 mass% or more is because an ore having a high crystallization water has a high specific surface area and can improve the granulation property of fine ore. Furthermore, it is preferable that 5 mass% or more of limestone is contained in the fine iron ore of 125 μm or less. It is preferable that 5 mass% or more of limestone is contained. By containing fine limestone, the mixing property of fine ore and limestone can be improved, and the sintering reaction can be promoted.
また、高速撹拌機で処理する焼結原料には、被覆する石灰分以外に、消石灰もしくは生石灰を３ｍａｓｓ％以下添加することが好ましい。消石灰もしくは生石灰を３ｍａｓｓ％以下添加するのが好ましいのは、消石灰もしくは生石灰の添加は、造粒粒子の圧壊強度を向上させて焼結原料充填層での通気性を向上させることができるためである。さらに、前記高速撹拌機に使用する焼結原料において、微粉鉄鉱石の割合が３０ｍａｓｓ％以上においては焼結原料を乾燥処理することが好ましい。３０ｍａｓｓ％以上で乾燥処理するのが好ましいのは、焼結過程における水分は蒸発させるための潜熱が必要であり、事前に乾燥させることで必要な粉コークス等の炭材を低減させることができるためである。 Moreover, it is preferable to add 3 mass% or less of slaked lime or quicklime to the sintering raw material processed with a high-speed stirrer in addition to the lime content to coat. It is preferable to add slaked lime or quicklime to 3 mass% or less because the addition of slaked lime or quicklime can improve the crushing strength of the granulated particles and improve the air permeability in the sintered raw material packed layer. . Furthermore, in the sintering raw material used for the high-speed stirrer, it is preferable that the sintering raw material is subjected to a drying treatment when the proportion of fine iron ore is 30 mass% or more. It is preferable to perform the drying process at 30 mass% or more because the moisture in the sintering process needs latent heat to evaporate, and the carbonaceous materials such as powdered coke can be reduced by drying in advance. It is.
本発明の焼結鉱の製造方法によれば、種々の焼結機を用いて高い生産性で高品位の焼結鉱を製造することができ、高炉原料として本発明で得られた焼結鉱を利用することで、高い生産性の高炉操業を行うことが可能となる。 According to the method for producing sintered ore of the present invention, high-quality sintered ore can be produced with high productivity using various sintering machines, and the sintered ore obtained in the present invention as a blast furnace raw material. By using this, it becomes possible to perform blast furnace operation with high productivity.
Claims (9)
In the sintered raw material used for the said high-speed stirrer, when the ratio of fine iron ore is 30 mass% or more, a raw material is dry-processed, The sintered ore of any one of Claims 1-8 characterized by the above-mentioned. Production method.
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| PCT/JP2016/069840 WO2017026203A1 (en) | 2015-08-11 | 2016-07-05 | Method for producing sintered ore |
| TR2018/01470T TR201801470T1 (en) | 2015-08-11 | 2016-07-05 | Sintered ore production method. |
| CN201680044876.3A CN107849633B (en) | 2015-08-11 | 2016-07-05 | The manufacturing method of sinter |
| TW105122674A TWI596213B (en) | 2015-08-11 | 2016-07-19 | Sinter manufacturing method |
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| TR201801470T1 (en) | 2018-05-21 |
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