JP4867394B2 - Non-calcined agglomerate for iron making - Google Patents
Non-calcined agglomerate for iron making Download PDFInfo
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 353
- 229910052742 iron Inorganic materials 0.000 title claims description 175
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 224
- 239000002245 particle Substances 0.000 claims description 133
- 239000000843 powder Substances 0.000 claims description 129
- 239000002994 raw material Substances 0.000 claims description 103
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 54
- 239000011707 mineral Substances 0.000 claims description 54
- 239000011230 binding agent Substances 0.000 claims description 53
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 229910000831 Steel Inorganic materials 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 11
- 239000010959 steel Substances 0.000 claims description 11
- 238000005054 agglomeration Methods 0.000 claims description 3
- 230000002776 aggregation Effects 0.000 claims description 3
- 239000008187 granular material Substances 0.000 claims description 3
- 238000005065 mining Methods 0.000 claims 1
- 238000005245 sintering Methods 0.000 description 31
- 238000000034 method Methods 0.000 description 30
- 238000002156 mixing Methods 0.000 description 29
- 238000009826 distribution Methods 0.000 description 20
- 239000000463 material Substances 0.000 description 20
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- 230000000052 comparative effect Effects 0.000 description 12
- 239000007789 gas Substances 0.000 description 12
- 230000007423 decrease Effects 0.000 description 11
- 238000005469 granulation Methods 0.000 description 11
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- 239000011398 Portland cement Substances 0.000 description 8
- 238000009792 diffusion process Methods 0.000 description 7
- 238000005554 pickling Methods 0.000 description 7
- 239000000428 dust Substances 0.000 description 6
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000010419 fine particle Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
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- 229910052595 hematite Inorganic materials 0.000 description 3
- 239000011019 hematite Substances 0.000 description 3
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 229910000805 Pig iron Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-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
- 238000001354 calcination Methods 0.000 description 2
- 239000011362 coarse particle Substances 0.000 description 2
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- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
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- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 244000144725 Amygdalus communis Species 0.000 description 1
- 235000011437 Amygdalus communis Nutrition 0.000 description 1
- 239000004484 Briquette Substances 0.000 description 1
- -1 CaO hydrates Chemical class 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
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- 235000019738 Limestone Nutrition 0.000 description 1
- 235000010627 Phaseolus vulgaris Nutrition 0.000 description 1
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- 229910021397 glassy carbon Inorganic materials 0.000 description 1
- 150000004677 hydrates Chemical class 0.000 description 1
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- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
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Description
本発明は、高炉などの製鉄炉で鉄原料として用いられる製鉄用非焼成塊成鉱に関する。 The present invention relates to an unfired agglomerated ore for iron making used as an iron raw material in an iron making furnace such as a blast furnace.
高炉などの堅型製鉄炉（以下、高炉を例に説明する）を用いて行われる銑鉄製造プロセスでは、炉内の原料充填層内に還元ガスを流通させるために、原料充填層内の空隙率を一定値以上に保つことが重要である。このため鉄原料などの炉内装入物は粒度分布が大きいことが望ましく、装入後に粉化するおそれがある装入物は、その強度を高めて粉化を抑制する必要がある。このため、特に大型高炉においては、粉鉱石を炭材の燃焼熱により焼き固めた焼結鉱や、粉鉱石をペレタイザーなどで球状に成形した後、１０００℃以上で高温加熱硬化させた焼成ペレットなどが広く用いられている。 In a pig iron manufacturing process performed using a solid iron furnace such as a blast furnace (hereinafter described as an example of a blast furnace), the porosity in the raw material packed bed is used to distribute the reducing gas in the raw material packed bed in the furnace. It is important to keep the above a certain value. For this reason, it is desirable that the furnace interior inclusions such as iron raw materials have a large particle size distribution, and it is necessary to increase the strength of the charges that may be pulverized after charging to suppress pulverization. For this reason, especially in large blast furnaces, sintered ore obtained by baking powdered ore with the heat of combustion of carbonaceous materials, or fired pellets obtained by forming powdered ore into a spherical shape with a pelletizer and then heat-hardening at 1000 ° C or higher Is widely used.
一方において、特に省エネルギーを目的として、高温加熱処理しない非焼成塊成鉱に関する検討も進められてきた。この非焼成塊成鉱は、焼結鉱粉や鉄鉱石粉をセメントなどの水硬性結合材をバインダーとして、常温または廃熱等を利用した数百℃以下の比較的低温の条件で一定期間養生して製造される。
セメントなどの水硬性結合材を用いると、冷間（常温）強度は十分に確保することができ、したがって製造場所から高炉への移送を容易に行うことができ、また、高炉上部の数百℃までの温度領域においては、その形状を保持させることができる。しかし、それ以上の高温域ではセメント水和物が熱分解するために、強度が著しく低下し、高炉中部および下部での粉化とそれに伴う通気性の悪化を生じることが古くから指摘されていた。
On the other hand, studies on non-fired agglomerated minerals that are not heat-treated at high temperatures have been promoted, particularly for the purpose of energy saving. This non-fired agglomerated mineral is cured for a certain period of time at a relatively low temperature of several hundred degrees C or less using normal or waste heat, etc., using sintered ore or iron ore powder as a binder with a hydraulic binder such as cement. Manufactured.
When using a hydraulic binder such as cement, sufficient cold (room temperature) strength can be ensured, so that it can be easily transferred from the production site to the blast furnace, and several hundred degrees Celsius above the blast furnace. In the temperature range up to, the shape can be maintained. However, it has been pointed out for a long time that the strength of the cement hydrate is significantly degraded at higher temperatures, resulting in a significant decrease in strength, resulting in pulverization in the middle and lower parts of the blast furnace and associated deterioration in air permeability. .
このような問題に対して、特許文献１には、鉄鉱石粉にアスファルトやピッチなどの粘着性炭化水素混合物をバインダーとして添加混合し、これを圧縮成形して硬化させた非焼成塊成鉱（成形体）が示されている。同文献によれば、この非焼成塊成鉱は２００℃程度からバインダー中の揮発分が蒸発し、バインダーの粘度が大きくなるため成形体の強度が増大し、８００℃程度で揮発分の蒸発がほぼ終了し、ガラス状の炭素が鉄鉱石粒子を結合するため成形体強度がさらに増加するとしている。
特許文献１は、非焼成塊成鉱の高温強度を改善する技術であるが、揮発分が２００℃から蒸発を始めると、還元ガスに随伴して高炉上部から排出されることになる。高炉から排出されるガスは、一般にＣＯガスなどの可燃分を含むため回収されるが、この回収工程に上記揮発分を伴う排ガスが流れると、揮発分が凝縮点以下の温度に冷却されたときにタールとなり、これが回収機器内面になどに固着してしまう。このため、高炉からの排出ガス回収が事実上できなくなるという欠点がある。
したがって本発明の目的は、このような従来技術の課題を解決し、常温及び炉内低温域から溶融直前の高温域に至る広い温度範囲において粉化が抑えられる高強度の製鉄用非焼成塊成鉱を提供することにある。 Accordingly, the object of the present invention is to solve such problems of the prior art, and to prevent high-strength non-fired agglomeration for iron making, which can suppress pulverization in a wide temperature range from room temperature and a low temperature range in the furnace to a high temperature range just before melting. To provide ore.
本発明者らは、非焼成塊成鉱の常温及び炉内低温域での強度はセメントなどの水硬性結合材により確保することを前提に、炉内高温域において水硬性結合材の結合強度が低下するのを補う方法について、以下のような検討を行った。
セメントはＣａＯが水和反応してＣａ（ＯＨ）２となることにより固化（水和硬化）するが、この水和物が５００℃程度に加熱されると、下記(1)式の反応により分解して強度が低下し、バインダーとしての機能を果たせなくなる。
Ｃａ（ＯＨ）２→ＣａＯ＋Ｈ２Ｏ …(1)
Based on the premise that the strength of the unfired agglomerated mineral at room temperature and in the furnace low temperature range is ensured by a hydraulic binder such as cement, the bond strength of the hydraulic binder in the furnace high temperature range is The following examination was conducted on a method for compensating for the decrease.
Cement solidifies (hydrates and hardens) when CaO hydrates to Ca (OH) 2 , but when this hydrate is heated to about 500 ° C, it decomposes by the reaction of the following formula (1). As a result, the strength decreases and the function as a binder cannot be achieved.
Ca (OH) 2 → CaO + H 2 O (1)
堅型製鉄炉（以下、高炉を例に説明する）上部に装入された非焼成塊成鉱は、炉頂部では高くても２００℃程度の雰囲気下にあるが、炉内を降下していくにしたがって次第に高温雰囲気に曝されるようになる。そして、そのような高温雰囲気下では上記(1)式の反応が起こり、そのままであれば非焼成塊成鉱の強度は低下し、割れや粉化などによって粒径が小さくなってしまう。このような問題に対して本発明者らは、上記高温雰囲気を利用して焼結する物質を非焼成塊成鉱に添加しておけば、無機バインダー（セメントなど）による結合に代わって焼結による結合が新たに生じ、高温強度を発現できるのではないかと考えた。 The uncalcined agglomerate charged in the upper part of the solid steel furnace (hereinafter described as an example of a blast furnace) is in an atmosphere of about 200 ° C. at the top of the furnace, but descends in the furnace. Gradually become exposed to a high temperature atmosphere. In such a high temperature atmosphere, the reaction of the above formula (1) occurs, and if it is left as it is, the strength of the unfired agglomerated ore is reduced, and the particle size becomes smaller due to cracking or pulverization. In order to solve this problem, the present inventors can sinter instead of bonding with an inorganic binder (such as cement) if a material to be sintered using the high temperature atmosphere is added to the unfired agglomerated mineral. It was thought that a new bond might be generated and high-temperature strength could be developed.
焼結反応については、多くの基礎的研究がなされているが、例えば、荒井康夫著，粉体の材料化学，培風館（1987），p143には、下記(2)式及び下記(3)式が提案されている。
ｘ：焼結により生成される接合部の長さ
Ｌ：焼結する２粒子の直径の和
ΔＬ：収縮量
Ｋ：定数
Ｄ：拡散係数
γ：表面エネルギー
ａ：イオン間距離
ｋ：ボルツマン定数
Ｔ：温度
ｔ：焼結時間
Many basic studies have been made on the sintering reaction. For example, Yasuo Arai, Material chemistry of powders, Baifukan (1987), p143 includes the following formulas (2) and (3): Proposed.
上記(2)式は、焼結により生成される接合部の長さを粒子半径で規格化したものを温度、粒子半径及び焼結時間により定式化したものであり、上記(3)式は、収縮率（ΔＬ／Ｌ）を同様に定式化したものである。ΔＬ及びＬの定義は図９に示した。
上記(2)式より、接合部の成長は拡散係数Ｄが大きいほど、焼結時間ｔが長いほど、粒子半径ｒが小さいほど大きいことが判る。拡散係数Ｄは物質によっても異なるが、結晶格子の欠陥濃度が少ない（不純物が少ない）ほど大きくなる。同様に上記(3)式より、焼結による収縮率（ΔＬ／Ｌ）は拡散係数Ｄが大きいほど、焼結時間ｔが長いほど、粒子半径ｒが小さいほど大きいことが判る。
The above equation (2) is the one obtained by standardizing the length of the joint produced by sintering with the particle radius, and is formulated with the temperature, the particle radius and the sintering time, and the above equation (3) is The shrinkage rate (ΔL / L) is similarly formulated. The definitions of ΔL and L are shown in FIG.
From the above equation (2), it can be seen that the growth of the joint is larger as the diffusion coefficient D is larger, the sintering time t is longer, and the particle radius r is smaller. Although the diffusion coefficient D varies depending on the material, the diffusion coefficient D increases as the defect concentration of the crystal lattice decreases (there are fewer impurities). Similarly, from the above equation (3), it can be seen that the shrinkage ratio (ΔL / L) by sintering is larger as the diffusion coefficient D is larger, the sintering time t is longer, and the particle radius r is smaller.
以上のことから、高純度で微粒の粒子を添加すれば、この粒子の焼結により高温域での非焼成塊成鉱の強度を高めることができるものと推定し、具体的な材料について実験と検討を重ねた結果、所定の粒径以下の酸化鉄粉を用いることが有効であることが判明した。すなわち、そのような酸化鉄粉を適量添加した非焼成塊成鉱は、水硬性結合材による結合強度の低下が始まる数百℃から酸化鉄粉が焼結をはじめ、この焼結により十分な熱間強度が確保できることが判った。また、このような鉄系の材料（酸化鉄粉）を用いることができることは、製鉄用塊成鉱としても望ましいことである。 From the above, it is estimated that the addition of high-purity fine particles can increase the strength of the non-fired agglomerated minerals at high temperatures by sintering these particles. As a result of repeated studies, it has been found effective to use iron oxide powder having a predetermined particle size or less. In other words, uncalcined agglomerated minerals to which an appropriate amount of such iron oxide powder has been added start to sinter the iron oxide powder from several hundred degrees Celsius at which the bond strength is lowered by the hydraulic binder, and sufficient heat is generated by this sintering. It was found that interstitial strength could be secured. In addition, the ability to use such an iron-based material (iron oxide powder) is desirable as an agglomerate for iron making.
本発明はこのような知見に基づきなされたもので、その要旨は以下のとおりである。
［1］製鉄用鉄原料（Ａ）に水硬性結合材（Ｂ）と粒径１０μｍ以下の割合が９０mass％以上の酸化鉄含有粉（Ｃ）（但し、粉体が酸化鉄のみからなる場合を含む。）を配合し、該酸化鉄含有粉（Ｃ）の含有量が酸化鉄換算量で１〜３０mass％である混合物を、前記水硬性結合材（Ｂ）をバインダーとして塊状に固化させたことを特徴とする製鉄用非焼成塊成鉱。
［2］上記［1］の製鉄用非焼成塊成鉱において、塊成鉱が造粒物の固化体、成型物の固化体、固化体の破砕物のいずれかであることを特徴とする製鉄用非焼成塊成鉱。
The present invention has been made based on such findings, and the gist thereof is as follows.
[1] Iron raw material for iron making (A) with hydraulic binder (B) and iron oxide-containing powder (C) with a particle size of 10 μm or less of 90 mass% or more (however, the case where the powder consists of iron oxide only) And the mixture of the iron oxide-containing powder (C) is 1-30 mass% in terms of iron oxide, and solidified in a lump using the hydraulic binder (B) as a binder. A non-fired agglomerated ore for iron making.
[2] The non-fired agglomerated ore for iron making according to [1] above, wherein the agglomerated mineral is one of a solidified product of a granulated product, a solidified product of a molded product, and a crushed product of the solidified product. Non-calcined agglomerated minerals.
［3］上記［1］又は［2］の製鉄用非焼成塊成鉱において、製鉄用鉄原料（Ａ）が粒径５ｍｍ未満の細粒焼結鉱又は／及び粒径５ｍｍ未満の細粒鉄鉱石であることを特徴とする製鉄用非焼成塊成鉱。
［4］上記［1］〜［3］のいずれかの製鉄用非焼成塊成鉱において、含有される酸化鉄含有粉（Ｃ）の個数が、製鉄用鉄原料（Ａ）の個数以上であることを特徴とする製鉄用非焼成塊成鉱。
[3] In the unfired agglomerated ore for iron making of [1] or [2] above, the iron raw material for iron making (A) is a fine-grained sintered ore having a particle size of less than 5 mm and / or a fine-grained iron ore having a particle size of less than 5 mm uncalcined agglomerated ore for steel, which is a stone.
[4] In the unfired agglomerated ore for iron making according to any one of [1] to [3], the number of iron oxide-containing powders (C) contained is equal to or greater than the number of iron raw materials for iron making (A). A non-fired agglomerated ore for iron making.
［5］上記［1］〜［4］のいずれかの製鉄用非焼成塊成鉱において、水硬性結合材（Ｂ）の含有量が２〜１０mass％であることを特徴とする製鉄用非焼成塊成鉱。
［6］上記［1］〜［5］のいずれかの製鉄用非焼成塊成鉱において、製鉄用鉄原料（Ａ）として、細粒焼結鉱（ａ１）を５５〜８０mass％、平均粒径が４０〜１００μｍの細粒鉄鉱石（ａ２）を１０〜２５mass％含有することを特徴とする製鉄用非焼成塊成鉱。
[5] The non-fired agglomerate for iron making according to any one of [1] to [4] , wherein the content of the hydraulic binder (B) is 2 to 10 mass%. Agglomerate.
[6] In the uncalcined agglomerated ore for iron making according to any one of [1] to [5 ] above, 55 to 80 mass%, average grain of fine-grained ore (a 1 ) as the iron raw material for iron making (A) A non-fired agglomerated ore for iron making, containing 10 to 25 mass% of fine-grained iron ore (a 2 ) having a diameter of 40 to 100 μm.
本発明の製鉄用非焼成塊成鉱は、常温及び炉内低温域（炉外でのハンドリング時、炉への移送・装入工程、炉装入初期段階における温度域）においては、水硬性結合材（Ｂ）によるバインダー作用により強度（冷間強度）が確保され、一方、炉内高温域においては添加した酸化鉄含有粉（Ｃ）の焼結により強度（熱間強度）が確保され、このため常温及び炉内低温域から溶融直前の炉内高温域までの広い温度範囲で粉化が抑制され、その形状を維持することができる。このため、堅型製鉄炉内の原料充填層の通気性を良好に保ち、高い生産性で銑鉄を製造することができる。 The non-fired agglomerated ore for iron making according to the present invention is hydraulically bonded at room temperature and in the low temperature range in the furnace (at the time of handling outside the furnace, the transfer and charging process to the furnace, the temperature range in the initial stage of furnace charging). Strength (cold strength) is secured by the binder action of the material (B), while strength (hot strength) is secured by sintering of the added iron oxide-containing powder (C) in the high temperature region in the furnace. Therefore, pulverization is suppressed in a wide temperature range from normal temperature and a low temperature range in the furnace to a high temperature range in the furnace immediately before melting, and the shape can be maintained. Therefore, it is possible to produce pig iron with high productivity while maintaining good air permeability of the raw material packed bed in the solid iron furnace.
本発明の製鉄用非焼成塊成鉱（以下、便宜上「非焼成塊成鉱」という）は、製鉄用鉄原料（Ａ）に水硬性結合材（Ｂ）と粒径１０μｍ以下の割合が９０mass％以上の酸化鉄含有粉（Ｃ）を配合した混合物を、前記水硬性結合材（Ｂ）をバインダーとして塊状に固化させたものである。このような焼成塊成鉱は、さきに述べたように、常温及び炉内低温域においては水硬性結合材（Ｂ）によるバインダー作用により強度（冷間強度）が確保され、炉内高温域においては添加した酸化鉄含有粉（Ｃ）の焼結により強度（熱間強度）が確保される。
本発明の非焼成塊成鉱は、高炉に代表される竪型製鉄炉（以下、高炉を例に説明する）において鉄原料として用いられる。
The non-fired agglomerated ore for iron making of the present invention (hereinafter referred to as “non-fired agglomerated ore” for convenience) has a ratio of the hydraulic binder (B) and the particle size of 10 μm or less to the iron raw material (A) for 90 mass%. A mixture in which the iron oxide-containing powder (C) is blended is solidified into a lump using the hydraulic binder (B) as a binder. As described above, such a fired agglomerated ore is ensured in strength (cold strength) by the binder action by the hydraulic binder (B) at room temperature and in the furnace low temperature region, and in the furnace high temperature region. The strength (hot strength) is ensured by sintering the added iron oxide-containing powder (C).
The unfired agglomerated ore of the present invention is used as an iron raw material in a vertical iron-making furnace represented by a blast furnace (hereinafter, a blast furnace will be described as an example).
図１は、本発明の非焼成塊成鉱の基本構造と昇温時の挙動を示しており、ｘは非焼成塊成鉱である。本発明の非焼成塊成鉱ｘの基本構造は、図１(イ)に示すように製鉄用鉄原料ａと水硬性結合材ｂの混合層と、この混合層内に散在する酸化鉄含有粉ｃ（粒径１０μｍ以下の割合が９０mass％以上の酸化鉄含有粉）からなる。このような非焼成塊成鉱ｘが高炉内に装入されて昇温されると、温度が概ね５００℃を超えたあたりから、酸化鉄含有粉ｃが焼結し始め、図１(ロ)に示すように、径を縮小させつつ、焼結した酸化鉄含有粉ｃをバインダーとする高い熱間強度を有する非焼成塊成鉱ｘ′になる。 FIG. 1 shows the basic structure of the unfired agglomerate of the present invention and the behavior at elevated temperature, where x is the unfired agglomerate. As shown in FIG. 1 (a), the basic structure of the unfired agglomerated mineral x of the present invention is a mixed layer of iron raw material a for iron making and a hydraulic binder b, and iron oxide-containing powder scattered in the mixed layer. c (iron oxide-containing powder having a particle size of 10 μm or less at 90 mass% or more). When such a non-fired agglomerated x is charged in a blast furnace and heated, the iron oxide-containing powder c starts to sinter from around the temperature exceeding 500 ° C., and FIG. As shown in Fig. 5, the non-fired agglomerated x 'having high hot strength using the sintered iron oxide-containing powder c as a binder while reducing the diameter.
図２は、酸化鉄含有粉ｃの粒子どうしの焼結挙動を模式的に示している。高温雰囲気下で粒子どうしが接触すると、界面で物質の拡散、移動が生じ接合する。この反応については、さきに挙げた(2)式および(3)式に従うことになる。本発明の非焼成塊成鉱ｘの場合には、図３に示すように、酸化鉄含有粉ｃと製鉄用鉄原料ａとの接触・接合を考えればよい。一般に製鉄用鉄原料ａは酸化鉄に様々な不純物を含んだものとなっており、また、その粒径もミリオーダーのものが多い。このため上記(2)式で示したように焼結速度は遅い。したがって、製鉄用鉄原料ａから酸化鉄含有粉ｃへの拡散は遅いが、酸化鉄含有粉ｃから製鉄用鉄原料ａへの拡散は速い。これによって、酸化鉄含有粉ｃが製鉄用鉄原料ａを接合する“のり”の役割を果たすことになる。 FIG. 2 schematically shows the sintering behavior of the particles of the iron oxide-containing powder c. When particles come into contact with each other in a high-temperature atmosphere, the material diffuses and moves at the interface and bonds. For this reaction, the equations (2) and (3) listed above are followed. In the case of the non-fired agglomerated x of the present invention, as shown in FIG. 3, contact / joining between the iron oxide-containing powder c and the iron raw material a for iron making may be considered. In general, the iron raw material a for iron making contains various impurities in iron oxide, and its particle size is often in the order of millimeters. For this reason, the sintering rate is slow as shown in the above equation (2). Therefore, diffusion from the iron-making iron raw material a to the iron oxide-containing powder c is slow, but diffusion from the iron oxide-containing powder c to the iron-making iron raw material a is fast. As a result, the iron oxide-containing powder c serves as a “paste” for joining the iron raw material a for iron making.
以下、本発明の非焼成塊成鉱の構成成分の詳細と限定理由について説明する。
前記製鉄用鉄原料（Ａ）としては、細粒焼結鉱、細粒鉄鉱石などが挙げられるが、これに限定されるものではなく、製鉄炉用の鉄原料となり得るものであって、そのままでは高炉に装入できない細粒状のものであればよい。
前記細粒焼結鉱の代表例は、鉄鉱石の焼結プロセスで返鉱と呼ばれる焼結鉱粉であり、従来の一般的な焼結プロセスでは、この焼結鉱粉は焼結工程に送り返され、焼結原料として使用されている。この焼結鉱粉の大部分は、成品焼結鉱を得る際の粒度選別工程で発生するが、高炉への輸送工程や高炉周辺で発生するものもある。従来の焼結プロセスでは、成品歩留まりは７０〜８０％程度であり、残りの２０〜３０％程度が返鉱（焼結鉱粉）として焼結工程に返送されている（すなわち、成品焼結鉱になることなくプロセス内で循環している）。したがって、本発明の非焼成塊成鉱の製鉄用鉄原料（Ａ）として、そのような焼結鉱粉を利用できることにより、焼結鉱を含めた塊成鉱のトータル歩留まりを大きく向上させることができる。
前記細粒鉄鉱石には鉄鉱石粉も含まれる。また、元々粒度の小さい鉄鉱石、整粒工程で生じた粒度の小さい鉄鉱石などのいずれを用いてもよい。
製鉄用鉄原料（Ａ）は、異なる種類のものを２種以上用いてもよい。この製鉄用鉄原料（Ａ）の粒径は、一般には５ｍｍ未満である。
Hereinafter, the detail and the reason for limitation of the structural component of the non-baking agglomerated mineral of this invention are demonstrated.
Examples of the iron raw material for iron making (A) include fine-grained sintered ore and fine-grained iron ore, but are not limited thereto, and can be used as an iron raw material for an iron making furnace. Then, any fine particles that cannot be charged into the blast furnace may be used.
A typical example of the fine-grained sintered ore is a sintered ore powder called return ore in the iron ore sintering process. In the conventional general sintering process, this sintered ore powder is sent back to the sintering process. It is used as a sintering raw material. Most of the sintered ore powder is generated in the particle size selection process when obtaining the product sintered ore, but there are also those generated in the transport process to the blast furnace and around the blast furnace. In the conventional sintering process, the product yield is about 70 to 80%, and the remaining 20 to 30% is returned to the sintering process as a return mineral (sintered ore powder) (that is, the product sintered ore). Circulates within the process without becoming). Therefore, by using such sintered ore powder as the iron raw material (A) for non-fired agglomerated minerals of the present invention, the total yield of agglomerated ores including sintered ore can be greatly improved. it can.
The fine-grained iron ore includes iron ore powder. Moreover, any of iron ore having a small particle size and iron ore having a small particle size generated in the sizing process may be used.
Two or more different types of iron raw materials (A) for iron making may be used. The particle size of the iron raw material (A) for iron making is generally less than 5 mm.
前記水硬性結合材（Ｂ）としては、水和硬化によって冷間で十分な強度を発現し得るものであれば特に制限はなく、例えば、高炉セメント、ポルトランドセメント、フライアッシュセメント、アルミナセメントなどの各種セメント、高炉水砕スラグ微粉末などが挙げられ、これらの１種以上を用いることができる。
非焼成塊成鉱中での水硬性結合材（Ｂ）の含有量は、少なすぎると冷間での十分な強度が得られず、一方、多すぎると製鉄用鉄原料（Ａ）の割合が減少して生産性が低下するなどの問題を生じるため、その含有量は２〜１０mass％程度が適当である。
The hydraulic binder (B) is not particularly limited as long as it can exhibit sufficient strength in the cold by hydration hardening, and examples thereof include blast furnace cement, Portland cement, fly ash cement, and alumina cement. Various types of cement, granulated blast furnace slag, and the like can be used, and one or more of these can be used.
If the content of the hydraulic binder (B) in the unfired agglomerated mineral is too small, sufficient strength cannot be obtained in the cold, while if too large, the ratio of the iron raw material (A) for iron making is too high. In order to reduce the productivity and reduce the productivity, the content is suitably about 2 to 10 mass%.
前記酸化鉄含有粉（Ｃ）は、酸化鉄を含有し、粒径１０μｍ以下の粉を９０mass％以上含むものであれば特別な制限はなく、実質的に酸化鉄のみからなる粉体であってもよい。また、酸化鉄含有粉（Ｃ）が酸化鉄以外の物質（例えば、ＳｉＯ２、Ａｌ２Ｏ３など）を含む場合には、当該物質は酸化鉄とともに粒子の一部として含まれていてもよいし、酸化鉄を含まない粒子として含まれてもよい。また、酸化鉄はＦｅ２Ｏ３（へマタイト）に限らず、Ｆｅ３Ｏ４（マグネタイト）、ＦｅＯであってもよい。
なお、この酸化鉄含有粉（Ｃ）の粒径の測定方法としては、例えば、レーザー回折式粒度分布測定装置を用いた測定法を適用することができる。この測定方法は、粒子にレーザービームを照射した場合、その回折・散乱光の強度および分布が粒子の粒度分布に依存することを利用するものであり、粒度分布を極めて精度良く測定することができる。
The iron oxide-containing powder (C) contains iron oxide and is not specifically limited as long as it contains 90 mass% or more of powder having a particle size of 10 μm or less. Also good. Further, when the iron oxide-containing powder (C) contains a substance other than iron oxide (for example, SiO 2 , Al 2 O 3, etc.), the substance may be contained as part of the particles together with the iron oxide. However, it may be contained as particles not containing iron oxide. The iron oxide is not limited to Fe 2 O 3 (hematite), but may be Fe 3 O 4 (magnetite) or FeO.
In addition, as a measuring method of the particle size of this iron oxide containing powder (C), the measuring method using a laser diffraction type particle size distribution measuring apparatus is applicable, for example. This measurement method utilizes the fact that when a particle is irradiated with a laser beam, the intensity and distribution of the diffracted / scattered light depends on the particle size distribution of the particle, and the particle size distribution can be measured with extremely high accuracy. .
図３に示すような焼結に有効な酸化鉄含有粉の粒度を決定するために、以下に示すような基礎試験を行った。図４に示すような非常に狭い粒度分布に整粒された酸化鉄粉（Ｆｅ２Ｏ３）を錠剤状に成形し、電気炉で焼成した後の収縮率を測定した。酸化鉄粉の粒径は６．５μｍ以下が９９．３mass％、５．５μｍ以下が１６．１mass％であり、これを６μｍで代表させた。高炉内でセメント水和物の分解が始まり、従来のセメントボンド型非焼成塊成鉱の強度が低下し始める温度は５００〜７００℃の領域であるため、酸化鉄粉の錠剤成形体の焼成温度を７００℃とし、高炉内で５００〜７００℃の滞留時間を考慮して焼成時間を１時間として焼結反応させた。このときの収縮率（ΔＬ／Ｌ）が０．０７１５であったことから、上記(3)式の未知数を決定し、粒径と収縮率の関係を求めて図５に示した。同図から、７００℃で収縮する最大の粒径を作図により決定した。図示した２つの直線（破線）は、粒径が小なる部分及び大なる部分における曲線の“直線に近い部分”を仮想的に延長したものであり、これらの交点をもって７００℃で収縮を開始する最大の粒径を求めると、収縮する最大の粒径は１０μｍと見積もられ、この粒径以下の粒子は収縮、すなわち焼結に寄与するものと推定される。以上の理由から、酸化鉄含有粉（Ｃ）は粒径１０μｍ以下のものが好ましく、このため本発明では粒径１０μｍ以下の割合が９０mass％以上の酸化鉄含有粉（Ｃ）を用いる。 In order to determine the particle size of the iron oxide-containing powder effective for sintering as shown in FIG. 3, a basic test as shown below was conducted. The iron oxide powder (Fe 2 O 3 ) adjusted to a very narrow particle size distribution as shown in FIG. 4 was formed into a tablet shape, and the shrinkage ratio after firing in an electric furnace was measured. The particle size of the iron oxide powder is 99.3 mass% at 6.5 μm or less and 16.1 mass% at 5.5 μm or less, and this was represented by 6 μm. Since the decomposition of cement hydrate begins in the blast furnace and the strength of the conventional cement bond-type non-fired agglomerated ore starts to decrease, the temperature is in the range of 500 to 700 ° C. The sintering reaction was carried out in a blast furnace with a firing time of 1 hour in consideration of a residence time of 500 to 700 ° C. Since the shrinkage rate (ΔL / L) at this time was 0.0715, the unknown in the above equation (3) was determined, and the relationship between the particle size and the shrinkage rate was determined and shown in FIG. From the figure, the maximum particle size that shrinks at 700 ° C. was determined by drawing. The two straight lines (broken lines) shown in the figure are virtual extensions of the “parts close to a straight line” of the curve where the particle size is small and large, and shrinkage starts at 700 ° C. at the intersection of these. When the maximum particle size is obtained, the maximum particle size that shrinks is estimated to be 10 μm, and particles smaller than this particle size are estimated to contribute to shrinkage, that is, sintering. For the reasons described above, the iron oxide-containing powder (C) preferably has a particle size of 10 μm or less. Therefore, in the present invention, the iron oxide-containing powder (C) having a particle size of 10 μm or less is 90 mass% or more.
粒径１０μｍ以下の割合が９０mass％以上の酸化鉄含有粉（Ｃ）としては、例えば、鋼材酸洗ライン回収粉（いわゆるルスナー酸化鉄など）、鉄鋼製造プロセスで生じる精錬ダスト、鉄鉱石微粉などが挙げられ、これらの１種以上を用いることができる。
ここで、鋼材酸洗ライン回収粉とは、次のようなものである。鋼板などの鋼材製造プロセスの冷間圧延工程では、圧延前に表面の酸化鉄層を酸洗（塩酸溶液による酸洗）することにより除去している。この酸洗液中に鉄は塩化鉄として溶出するが、この塩化鉄を焙焼などの方法で処理することにより、高純度且つ微粉の酸化鉄粉（ヘマタイト粉）が回収される。この酸化鉄粉は非常に高純度（通常、酸化鉄含有率：９５mass％以上）で微粉のものであり、本発明の酸化鉄含有粉（Ｃ）として好適なものである。
Examples of the iron oxide-containing powder (C) having a particle size of 10 μm or less of 90 mass% or more include steel pickling line recovered powder (so-called Rusner iron oxide, etc.), refined dust generated in the steel manufacturing process, iron ore fine powder, and the like. One or more of these can be used.
Here, the steel material pickling line recovered powder is as follows. In the cold rolling step of a steel material manufacturing process such as a steel plate, the surface iron oxide layer is removed by pickling (pickling with a hydrochloric acid solution) before rolling. In this pickling solution, iron is eluted as iron chloride. By treating this iron chloride by a method such as roasting, high purity and fine iron oxide powder (hematite powder) is recovered. This iron oxide powder is very high purity (usually iron oxide content: 95 mass% or more) and fine powder, and is suitable as the iron oxide-containing powder (C) of the present invention.
また、鋼製造プロセスで生じる精錬ダストには、溶銑予備処理工程で生じる精錬ダスト、転炉脱炭工程で生じる精錬ダスト（転炉ＯＧダスト）などが含まれる。これらの精錬ダストは、精錬工程で発生した排ガスから集塵することにより回収されたものである。これらのダストは、酸化鉄粉の含有量が高く且つ微粉のものであり、本発明の酸化鉄含有粉（Ｃ）として好適なものである。
非焼成塊成鉱中での酸化鉄含有粉（Ｃ）の含有量は、酸化鉄換算量で１〜３０mass％、特に５〜３０mass％とすることが好ましい。酸化鉄含有粉（Ｃ）の含有量が酸化鉄換算量で１mass％未満では、酸化鉄含有粉（Ｃ）の焼結によるバインダー作用が十分でなく、一方、３０mass％を超えると、製鉄用鉄原料（Ａ）の量が少なくなるため生産性が低下する。
Further, the refining dust generated in the steel production process includes refining dust generated in the hot metal pretreatment process, refining dust (converter OG dust) generated in the converter decarburization process, and the like. These refining dusts are collected by collecting dust from the exhaust gas generated in the refining process. These dusts have a high content of iron oxide powder and are fine powder, and are suitable as the iron oxide-containing powder (C) of the present invention.
The content of the iron oxide-containing powder (C) in the unfired agglomerated mineral is preferably 1 to 30 mass%, particularly 5 to 30 mass%, in terms of iron oxide. If the content of the iron oxide-containing powder (C) is less than 1 mass% in terms of iron oxide, the binder action due to sintering of the iron oxide-containing powder (C) is not sufficient, while if it exceeds 30 mass%, the iron for iron making Productivity decreases because the amount of the raw material (A) decreases.
さらに、非焼成塊成鉱により高い熱間強度を発現するための酸化鉄含有粉（Ｃ）含有量の好ましい条件は、次のとおりである。まず、図３からして、酸化鉄含有粉（Ｃ）が製鉄用鉄原料（Ａ）の粒子の「のり」として機能するためには、粒子の個数が等量以上存在すればよいと考えられる。このとき下記(4)式及び(5)式が成り立ち、これら２つの式から下記(6)式が得られる。
ρ ：粒子の真密度（ｔ／ｍ３）
Ｖｐ：粒子一個の体積（ｍ３）
ｄｐ：粒子の直径（ｍ）
＊ ：大粒子を表す添え字。添え字のないものは小粒子を表す。
ρ: true density of particles (t / m 3 )
Vp: Volume of one particle (m 3 )
dp: particle diameter (m)
*: Subscript representing large particles. Those without subscripts represent small particles.
簡単のため、粒径を２成分系で考える。ここで、小粒子は酸化鉄含有粉（Ｃ）であり、前述の検討から代表径を１０μｍとした。代表径を１０μｍとして検討すると、これよりも粒径が小である場合は、配合量同一の場合、粒子個数は増大し焼結に有利な方向に作用することになる。一方、大粒子は製鉄用鉄原料（Ａ）であり、これについては代表径を４０μｍとした。これは、下記のような事実に基づいている。塊成化するためには一般に粒径が小さい方が有利である（比表面積を大きくすると、粒子間の接触界面積が増大するため）ので、粉砕して用いることが広く行われている。しかしながら、粉砕にかかるコストを考えるとせいぜい４０μｍ程度までの粉砕にとどめることが多い。代表径が４０μｍよりも大きいと粒子個数は減少し、相対的に酸化鉄含有粉（Ｃ）の粒子数が増大するため焼結に有利な方向に作用する。製鉄用鉄原料（Ａ）の代表径を４０μｍとした場合、上記(6)式から酸化鉄含有粉（Ｃ）は酸化鉄換算量で概ね２mass％配合すれば良いことになる。 For simplicity, the particle size is considered in a two-component system. Here, the small particles are iron oxide-containing powder (C), and the representative diameter was set to 10 μm from the above-described examination. When the representative diameter is considered to be 10 μm, if the particle diameter is smaller than this, the number of particles increases and acts in an advantageous direction for sintering if the blending amount is the same. On the other hand, the large particles are the iron raw material (A) for iron making, and the representative diameter is 40 μm. This is based on the following facts. In order to agglomerate, it is generally more advantageous to have a smaller particle size (since a larger specific surface area increases the contact interface area between the particles), it is widely used after pulverization. However, considering the cost of pulverization, the pulverization is often limited to about 40 μm at most. When the representative diameter is larger than 40 μm, the number of particles decreases, and the number of particles of the iron oxide-containing powder (C) increases relatively, which acts in an advantageous direction for sintering. When the representative diameter of the iron raw material for iron making (A) is set to 40 μm, the iron oxide-containing powder (C) may be blended in an amount of about 2 mass% in terms of iron oxide from the above formula (6).
製鉄用鉄原料（Ａ）を４０μｍ以下に粉砕して用いる場合には、厳密に(6)式によって小粒子の配合量を計算する必要がある。
上記(6)式で小粒子の粒径を１０μｍ、密度を４ｔ／ｍ３、大粒子の粒径を１０〜５０μｍ、密度を３．８ｔ／ｍ３とした計算結果を図６に示した。また、製鉄用鉄原料（Ａ）として粒径を４０μｍ，３０μｍ，２０μｍ，１５μｍ，１０μｍに調整したもの（各粒度以下の量を１０mass％以下に調整）を準備し、さまざまな配合比で酸化鉄含有粉（Ｃ）（この場合はヘマタイト粉）と混合し、前述と同様のタブレット焼成試験を行い、強度が５００Ｐａ以上となる配合量を図６に併せて示した。これによれば、大粒子（製鉄用鉄原料（Ａ））の粒径が２０μｍまでは、上記(6)式の計算値とよく一致したが、２０μｍよりも小さくなると、小粒子（酸化鉄含有粉（Ｃ））の配合率は計算値に比較して少量でよいことが判った。これは、大粒子（製鉄用鉄原料（Ａ））の粒径が小さくなってくると、それ自身が焼結を始めることに起因するものと推定される。
When the iron raw material (A) for iron making is used after being pulverized to 40 μm or less, it is necessary to strictly calculate the blending amount of small particles by the equation (6).
FIG. 6 shows the calculation results obtained when the particle size of the small particles is 10 μm, the density is 4 t / m 3 , the particle size of the large particles is 10 to 50 μm, and the density is 3.8 t / m 3 in the above equation (6). In addition, iron raw materials (A) for iron making are prepared with particle sizes adjusted to 40 μm, 30 μm, 20 μm, 15 μm, and 10 μm (the amount below each particle size is adjusted to 10 mass% or less), and iron oxide is prepared in various compounding ratios. It mixes with containing powder (C) (in this case hematite powder), the tablet baking test similar to the above was done, and the compounding quantity from which intensity | strength becomes 500 Pa or more was shown collectively in FIG. According to this, until the particle size of large particles (iron raw material (A) for iron making) is 20 μm, it agrees well with the calculated value of the above formula (6), but when it is smaller than 20 μm, small particles (containing iron oxide) It was found that the blending ratio of the powder (C) may be a small amount compared to the calculated value. This is presumably due to the fact that when the particle size of the large particles (iron raw material for iron making (A)) becomes smaller, the particles themselves start sintering.
したがって、酸化鉄含有粉（Ｃ）の焼結による熱間強度を十分に発現させるためには、含有される酸化鉄含有粉（Ｃ）の個数が、製鉄用鉄原料（Ａ）の個数以上であることが望ましく、さらに好ましくは、製鉄用鉄原料（Ａ）の粒度分布に応じて、酸化鉄含有粉（Ｃ）の含有量が下記（1）〜（3）の条件を満足することが望ましい。
（1）製鉄用鉄原料（Ａ）に占める粒径４０μｍ以下の原料粒子の割合が１０mass％以下の場合は、酸化鉄含有粉（Ｃ）の含有量を酸化鉄換算量で２mass％以上とする。
（2）製鉄用鉄原料（Ａ）に占める粒径３０μｍ以下の原料粒子の割合が１０mass％以下の場合は、酸化鉄含有粉（Ｃ）の含有量を酸化鉄換算量で５mass％以上とする。
（3）製鉄用鉄原料（Ａ）に占める粒径２０μｍ以下の原料粒子の割合が１０mass％以下の場合は、酸化鉄含有粉（Ｃ）の含有量を酸化鉄換算量で１０mass％以上とする。
Therefore, in order to fully develop the hot strength due to sintering of the iron oxide-containing powder (C), the number of iron oxide-containing powder (C) contained is equal to or greater than the number of iron raw materials for iron making (A). More preferably, the content of the iron oxide-containing powder (C) preferably satisfies the following conditions (1) to (3), depending on the particle size distribution of the iron raw material (A) for iron making. .
(1) When the proportion of raw material particles having a particle size of 40 μm or less in the iron raw material (A) for iron making is 10 mass% or less, the content of the iron oxide-containing powder (C) is 2 mass% or more in terms of iron oxide .
(2) When the ratio of raw material particles having a particle size of 30 μm or less in the iron raw material (A) for iron making is 10 mass% or less, the content of the iron oxide-containing powder (C) is set to 5 mass% or more in terms of iron oxide. .
(3) When the ratio of the raw material particles having a particle size of 20 μm or less in the iron raw material (A) for iron making is 10 mass% or less, the content of the iron oxide-containing powder (C) is set to 10 mass% or more in terms of iron oxide. .
また、本発明の非焼成塊成鉱は、製鉄用鉄原料（Ａ）として、細粒焼結鉱（鉄鉱石の焼結プロセスで発生する返鉱など）を５５〜８０mass％、平均粒径が４０〜１００μｍの細粒鉄鉱石（ａ２）を１０〜２５mass％含有することが、塊成鉱内部での原料の充填度を高め、冷間および熱間での強度を確保する上で特に好ましい。すなわち、通常、返鉱に代表される細粒焼結鉱（ａ１）の粒度は５ｍｍ以下であり、このような粒度の細粒焼結鉱（ａ１）に対して平均粒径が４０〜１００μｍの細粒鉄鉱石（ａ２）を配合することにより、製鉄用鉄原料（Ａ）の充填度が高まる。 Moreover, the non-fired agglomerated mineral of the present invention is a fine-grained sintered ore (returning or the like generated in the iron ore sintering process) as an iron raw material (A) for iron making, and has an average particle size of 55 to 80 mass%. It is particularly preferable to contain 10 to 25 mass% of fine-grained iron ore (a 2 ) having a size of 40 to 100 μm in order to increase the filling degree of the raw material inside the agglomerated mineral and to ensure the strength between cold and hot. . That is, the particle size of fine-grained sinter (a 1 ), typically represented by return ore, is 5 mm or less, and the average particle size is 40 to less than that of fine-grained sinter (a 1 ) with such particle size. By adding 100 μm fine-grained iron ore (a 2 ), the filling degree of the iron raw material (A) for iron making is increased.
ここで、非焼成塊成鉱中での細粒焼結鉱（ａ１）の割合が５５mass％未満では、返鉱に代表される細粒焼結鉱の有効利用ができない上、コストも高くなる。一方、８０mass％超では細粒鉄鉱石（ａ２）の割合が低下して充填度が低くなるとともに、強度を発現させるための原料の配合量も少なくなり、冷間及び熱間での強度を確保する上で不利になる。また、上記細粒鉄鉱石（ａ２）の割合が１０mass％未満では製鉄用鉄原料（Ａ）の充填度が十分でなく、一方、２５mass％を超えると細粒焼結鉱（ａ１）の割合が低下してしまう。 Here, if the ratio of the fine-grained sintered ore (a 1 ) in the non-fired agglomerated mineral is less than 55 mass%, the fine-grained sintered ore represented by return ore cannot be effectively used, and the cost also increases. . On the other hand, if it exceeds 80 mass%, the proportion of fine-grained iron ore (a 2 ) decreases and the degree of filling decreases, and the blending amount of raw materials for developing strength decreases, and the strength between cold and hot is reduced. It will be disadvantageous in securing. Further, when the proportion of the fine-grained iron ore (a 2 ) is less than 10 mass%, the filling degree of the iron raw material (A) for iron making is not sufficient, while when it exceeds 25 mass%, the fine-grained sintered ore (a 1 ) The rate will drop.
また、本発明の非焼成塊成鉱は、製鉄用鉄原料（Ａ）、水硬性結合材（Ｂ）及び酸化鉄含有粉（Ｃ）を主たる構成成分とするものであるが、必要に応じて他の成分、例えば、各種分散剤、硬化促進剤、石灰石微粉、フライアッシュ、シリカ微粉などの１種以上を、本発明の効果を損なわない限度で適量配合することもできる。これらその他成分の非焼成塊成鉱中での合計配合量は１０mass％程度、特に望ましくは５mass％程度を上限とすることが好ましい。但し、コークス粉等の還元材については、別途、その使用目的に応じて２０mass％程度を上限として配合してもよい。
本発明の非焼成塊成鉱の粒径（常温雰囲気下での球換算粒径）は８〜３０ｍｍ程度が好ましい。非焼成塊成鉱の粒径が８ｍｍ未満では、炉に装入した際の原料充填層の通気性が悪化するおそれがあり、一方、粒径が３０ｍｍを超えると還元性が低下するおそれがある。
In addition, the non-fired agglomerated ore of the present invention is mainly composed of the iron raw material for iron making (A), the hydraulic binder (B), and the iron oxide-containing powder (C), but as necessary. One or more other components such as various dispersants, hardening accelerators, limestone fine powder, fly ash, silica fine powder and the like can be blended in an appropriate amount as long as the effects of the present invention are not impaired. The total blending amount of these other components in the non-fired agglomerated ore is preferably about 10 mass%, particularly preferably about 5 mass%. However, about reducing materials, such as coke powder, you may mix | blend about 20 mass% separately as an upper limit according to the use purpose.
The particle size of the unfired agglomerated mineral of the present invention (spherical equivalent particle size in a normal temperature atmosphere) is preferably about 8 to 30 mm. If the particle size of the unfired agglomerated mineral is less than 8 mm, the air permeability of the raw material packed layer when charged in the furnace may be deteriorated. On the other hand, if the particle size exceeds 30 mm, the reducibility may be reduced. .
本発明の非焼成塊成鉱は、通常、造粒物の固化体、成型物の固化体、固化体（例えば、成型固化体や不定形固化体）の破砕物などとして得られる。
造粒物の固化体の場合には、原料（＝製鉄用鉄原料（Ａ）＋水硬性結合材（Ｂ）＋酸化鉄含有粉（Ｃ）＋さらに必要に応じて他の成分。以下同様）と水を混合・撹拌（混練）した後、造粒を行い、得られた造粒物を一定期間養生させることにより、非焼成塊成鉱の成品を得る。造粒方法は任意であるが、代表的な方法としては、ディスクペレタイザーやドラム型造粒機を用いる転動造粒法、ブリケット成形機を用いる圧縮造粒法などがあり、いずれを用いてもよい。
The non-fired agglomerated ore of the present invention is usually obtained as a solidified product of a granulated product, a solidified product of a molded product, a crushed product of a solidified product (for example, a molded solidified product or an amorphous solidified product), and the like.
In the case of a solidified product of the granulated material, the raw material (= iron raw material for iron making (A) + hydraulic binder (B) + iron oxide-containing powder (C) + other components as necessary, the same applies hereinafter) After mixing and stirring (kneading) and water, granulation is performed, and the resulting granulated product is cured for a certain period of time to obtain a product of non-fired agglomerated mineral. The granulation method is arbitrary, but as a typical method, there are a rolling granulation method using a disk pelletizer or a drum type granulator, a compression granulation method using a briquette molding machine, etc. Good.
ブリケット成形機は粒子群を機械的に圧縮するため、成形物の充填率が高まり、グリーン強度（成形直後の強度。これに対して冷間強度とは、成形後一定の養生期間を経過してバインダーが固化した後の粒子の強度を言う。）は増大する傾向にあるが、養生後の冷間強度はバインダーの質や量に依存するところが大きく、転動造粒法と圧縮造粒法で大きな違いはない。また、熱間強度も前述のような酸化鉄含有粉（Ｃ）の焼結接合によっているため、両造粒方法での違いはほとんどない。一般的には、圧縮造粒法は転動造粒法に比較して粒度や性状の均一なものができやすい一方で、設備費や補修費用が高いという特徴がある。したがって、造粒方法については、以上の点を考慮して適宜選択すればよい。 Since the briquetting machine mechanically compresses the particle group, the filling rate of the molded product increases, and the green strength (strength immediately after molding. On the other hand, the cold strength is a certain curing period after molding. (The strength of the particles after the binder is solidified.) Tends to increase, but the cold strength after curing depends largely on the quality and quantity of the binder, and it depends on the rolling granulation method and the compression granulation method. There is no big difference. Moreover, since the hot strength is based on the sintered joining of the iron oxide-containing powder (C) as described above, there is almost no difference between the two granulation methods. In general, the compression granulation method is characterized in that it is easy to produce a uniform particle size and properties as compared with the rolling granulation method, but has high equipment costs and repair costs. Therefore, the granulation method may be appropriately selected in consideration of the above points.
また、成型物の固化体の場合には、原料と水を混合・撹拌（混練）したものを型に流し込んで成型し、その後、一定期間養生させることにより、非焼成塊成鉱の成品を得ることができる。
また、固化体の破砕物の場合には、上記成型物と同じような方法で得られた成型固化体や、原料と水を混合・撹拌したものを湿式吹き付けし、これを一定期間養生させることにより得られた不定形固化体を、適当な破砕手段で破砕して非焼成塊成鉱の成品を得ることができる。
Further, in the case of a solidified product of a molded product, a raw material and water mixed and stirred (kneaded) are poured into a mold, molded, and then cured for a certain period of time to obtain a non-baked agglomerated product. be able to.
Also, in the case of a crushed solidified product, the molded solidified product obtained by the same method as the above molded product or a mixture / stirred mixture of raw material and water is wet sprayed and cured for a certain period of time. The non-fired agglomerated mineral product can be obtained by crushing the amorphous solid body obtained by the above-mentioned method with an appropriate crushing means.
図７に、本発明の非焼成塊成鉱の製造フローの一例を示す。
図において、１ａ〜１ｃは、製鉄用鉄原料（Ａ）、水硬性結合材（Ｂ）及び酸化鉄含有粉（Ｃ）をそれぞれ貯留した原料貯留槽であり、これら原料貯留槽１ａ〜１ｃから定量切り出し装置などを用いて、製鉄用鉄原料（Ａ）、水硬性結合材（Ｂ）及び酸化鉄含有粉（Ｃ）を所定量切り出し、原料搬送装置２により加湿混合機３（例えば、ドラムミキサー、アイリッヒミキサーなど）へ導入する。なお、製鉄用鉄原料（Ａ）、水硬性結合材（Ｂ）及び酸化鉄含有粉（Ｃ）は予め混合し、１つの原料貯留槽から切り出すようにしてもよい。また、図示しないが、必要に応じて事前に粒度を調整するための粉砕工程や、異物を取り除く工程などがあってもよい。
前記加湿混合機３では原料に水が添加され、混合・撹拌される。加湿混合機３の機能などに特別な制限はないが、混合攪拌能力の高いものが望ましい。混合攪拌能力の低いものを採用した場合は、混合時間を長く取る必要が生じ、生産性が低下する。
In FIG. 7, an example of the manufacturing flow of the non-baking agglomerated mineral of this invention is shown.
In the figure, reference numerals 1a to 1c denote raw material storage tanks in which iron raw materials for iron making (A), hydraulic binders (B), and iron oxide-containing powders (C) are stored, respectively, and are quantitatively determined from these raw material storage tanks 1a to 1c. Using a cutting device or the like, a predetermined amount of iron raw material for iron making (A), hydraulic binder (B), and iron oxide-containing powder (C) is cut out, and the raw
In the humidifying mixer 3, water is added to the raw material and mixed and stirred. Although there is no special restriction | limiting in the function of the humidification mixer 3, etc., a thing with high mixing stirring ability is desirable. In the case where a material having a low mixing and stirring ability is adopted, it is necessary to take a long mixing time, and productivity is lowered.
前記加湿混合機３で加湿混合された原料は原料搬送装置４により造粒機５に移送され、ここで造粒される。図７では造粒機５として皿型転動造粒機（ディスクペレタイザー）を用いているが、さきに述べたように他の形式の造粒機を用いてもよい。
図７のような皿型転動造粒機を用いた場合には、球形に近い塊成鉱（造粒物）が製造される。一方、圧縮造粒機を用いた場合には、アーモンド形、豆炭形など、使用する型によりさまざまな形状のものが製造可能である。但し、さきに述べたように常温雰囲気下での球換算粒径が８〜３０ｍｍ程度であれば、どのような形状でもよい。
造粒機５で得られた造粒物（塊成化物）は原料搬送装置６により静置ヤード７へ搬送され、この静置ヤード７で所定時間養生されることにより、高炉で使用可能な非焼成塊成鉱ｘとなる。
The raw material humidified and mixed by the humidifying mixer 3 is transferred to the granulator 5 by the raw
When a dish-type rolling granulator as shown in FIG. 7 is used, an agglomerate (granulated material) that is nearly spherical is produced. On the other hand, when a compression granulator is used, various shapes such as an almond shape and a bean charcoal shape can be manufactured depending on the type used. However, as described above, any shape may be used as long as the spherical equivalent particle diameter in a normal temperature atmosphere is about 8 to 30 mm.
The granulated product (agglomerated product) obtained by the granulator 5 is conveyed to the
［実施例１］
図７に示すような製造設備を用いて製鉄用非焼成塊成鉱を製造した。
この実施例では、製鉄用鉄原料（Ａ）として粒度分布が異なる鉄鉱石粉を用いた。また、酸化鉄含有粉（Ｃ）としては鋼材酸洗ライン回収粉を用いた。また、水硬性結合材（Ｂ）としてはポルトランドセメントを用いた。
使用した原料の成分組成を表１に、また粒度分布を図８に示す。製鉄用鉄原料(A1),(A2)は成分は同じであるが、製鉄用鉄原料(A1)は粒度がやや細かく、粒径２０μｍ以下が１０mass％以下のものである。一方、製鉄用鉄原料(A2)は粒度がやや粗く、粒径４０μｍ以下が１０mass％以下のものである。
[Example 1]
An unfired agglomerated ore for iron making was produced using a production facility as shown in FIG.
In this example, iron ore powder having a different particle size distribution was used as the iron raw material (A) for iron making. Moreover, steel material pickling line collection | recovery powder was used as iron oxide containing powder (C). Portland cement was used as the hydraulic binder (B).
The component composition of the raw materials used is shown in Table 1, and the particle size distribution is shown in FIG. The iron-making iron raw materials (A1) and (A2) have the same components, but the iron-making iron raw material (A1) has a slightly fine particle size and a particle size of 20 μm or less is 10 mass% or less. On the other hand, the iron raw material (A2) for iron making has a slightly coarse particle size, and a particle size of 40 μm or less is 10 mass% or less.
また、酸化鉄含有粉(C1)は酸化鉄含有率が極めて高く、且つ微細粒のものであり、粒径１０μｍ以下の割合が９０mass％以上のものである。一方、酸化鉄含有粉(C2)は酸化鉄含有率が極めて高いが、粒度は粗く粒径１０μｍ超の割合が４０mass％近くあるものである。
上記原料を図７に示す製造フローに従い処理し（造粒・養生）、発明例及び比較例の非焼成塊成鉱を製造した。そして、この非焼成塊成鉱を鉄原料の一部として高炉に装入し、操業を行った。その結果を、非焼成塊成鉱の原料配合割合、冷間強度、高炉操業条件・操業成績とともに表２に示す。なお、表２の比較例１の冷間強度は、使用した焼成塊成鉱（焼成ペレット）の冷間強度を示している。
Further, the iron oxide-containing powder (C1) has an extremely high iron oxide content and is a fine particle, and the ratio of the particle size of 10 μm or less is 90 mass% or more. On the other hand, the iron oxide-containing powder (C2) has an extremely high iron oxide content, but the particle size is coarse and the ratio of the particle size exceeding 10 μm is close to 40 mass%.
The said raw material was processed according to the manufacturing flow shown in FIG. 7 (granulation and curing), and the unfired agglomerated minerals of the inventive examples and comparative examples were manufactured. Then, the unfired agglomerated ore was charged into a blast furnace as a part of the iron raw material and operated. The results are shown in Table 2 together with the raw material blending ratio, cold strength, blast furnace operating conditions and operating results of the unfired agglomerated ore. In addition, the cold intensity | strength of the comparative example 1 of Table 2 has shown the cold intensity | strength of the used calcination agglomerate (calcination pellet).
比較例１を除く各実施例では、高炉への鉄原料の配合割合を非焼成塊成鉱：１２mass％、焼結鉱：７９mass％、塊鉱石：９mass％とした。一方、比較例１では、非焼成塊成鉱は使用せず、焼成塊成鉱（焼成ペレット）：１２mass％、焼結鉱：７９mass％、塊鉱石：９mass％とした。焼成ペレットは、現在の高炉操業で広く用いられているもので、背景技術の項で説明したように鉄鉱石粉を造粒した後、１０００℃以上の高温で焼き固めたものであるため、極めて高強度化する一方で、その製造のためにエネルギーを多量に消費するという問題がある。 In each Example except the comparative example 1, the mixture ratio of the iron raw material to a blast furnace was made into non-baking agglomerated mineral: 12 mass%, sintered ore: 79 mass%, lump ore: 9 mass%. On the other hand, in Comparative Example 1, non-calcined agglomerated mineral was not used, and calcined agglomerated mineral (calcined pellet): 12 mass%, sintered ore: 79 mass%, and ore: 9 mass%. The calcined pellets are widely used in the current blast furnace operation, and as described in the background section, after granulating iron ore powder, it is baked and hardened at a high temperature of 1000 ° C. or higher. While increasing the strength, there is a problem that a large amount of energy is consumed for the production.
発明例及び比較例の各非焼成塊成鉱（比較例１は焼成塊成鉱）の冷間強度を調査するため、ヤードにおける粉率と高炉炉頂における粉率を測定し、その差をもって輸送時粉化量を求めた。塊成鉱が５ｍｍ以上の粒径であれば高炉の原料として使用可能であるため、−５ｍｍ（＝粒径５ｍｍ未満）の粒子を粉と定義し、その質量割合を−５ｍｍの粉率とした。
塊成鉱の冷間強度が大きい方が輸送時粉化量を低減できる。実施例の塊成鉱の粉化量をみると焼成塊成鉱が最も小さいが、他の非焼成塊成鉱も概ね１mass％以下の粉化量であり、冷間強度については問題ないレベルであった。
In order to investigate the cold strength of each non-calcined agglomerate of the invention example and the comparative example (Comparative Example 1 is a calcined agglomerate), the powder rate at the yard and the powder rate at the top of the blast furnace were measured, and the difference was transported. The amount of powdered powder was obtained. If the agglomerate has a particle size of 5 mm or more, it can be used as a raw material for a blast furnace. Therefore, particles of −5 mm (= particle size less than 5 mm) are defined as powder, and the mass ratio is set to a powder rate of −5 mm. .
The larger the cold strength of the agglomerate, the lower the amount of powder during transportation. Looking at the agglomeration amount of the agglomerated minerals in the examples, the calcined agglomerated ore is the smallest, but the other non-calcined agglomerated ore is also the amount of pulverization of 1 mass% or less, and the cold strength is at a level with no problem. there were.
また、表２中に示した吹き抜け回数の「吹き抜け現象」とは、高炉内の圧力損失が増大することで還元性ガスの流れが止められ、炉内の圧力が上昇し、一定の圧力に達したとき、爆発的に還元性ガスの上昇が再開される現象を指す。この場合、ガス流れの再開と同時に炉内の装入物がガスに同伴されて移動するため、層状に堆積された装入物の分布が乱れることになる。装入物の分布が乱れると、通気性がさらに悪化したり、酸化鉄の還元不良等の問題を生じるため、還元材比が上昇するなど高炉操業に極めて悪い影響を与えるのみならず、圧力の上昇により炉体への機械的ダメージを与えたり、急激に高温ガスが噴出することによる諸設備への熱的悪影響も懸念される。 Also, the “blow-out phenomenon” of the number of blow-throughs shown in Table 2 means that the flow of reducing gas is stopped by increasing the pressure loss in the blast furnace, the pressure in the furnace rises, and reaches a certain pressure. When this happens, it means a phenomenon in which the rising of the reducing gas explosively resumes. In this case, since the charge in the furnace moves with the gas simultaneously with the resumption of the gas flow, the distribution of the charge deposited in layers is disturbed. If the distribution of the charge is disturbed, the air permeability is further deteriorated, and problems such as poor reduction of iron oxide are caused. There is also concern about thermal adverse effects on various facilities due to mechanical damage to the furnace body due to the rise and rapid hot gas ejection.
発明例１は、非焼成塊成鉱の原料配合割合を水硬性結合材：７mass％、製鉄用鉄原料(A1)：８１mass％、酸化鉄含有粉(C1)：１２mass％としたものである。この非焼成塊成鉱は、水硬性結合材による接合で冷間における強度は十分（輸送時粉化量は０．９mass％と小さい）である。また、高炉の操業を見ると、出銑量も多く還元材比も低く、吹き抜け現象も起きていない。これは、配合した酸化鉄含有粉(C1)が高炉内で加熱されることにより焼結し、熱間においても高い強度が維持できたためであると考えられる。なお、酸化鉄含有粉（Ｃ）の配合量は、製鉄用鉄原料（Ａ）の粒度分布が２０μｍ以下が１０mass％以下であるため、１０mass％以上が望ましいところ、本発明例では１２mass％配合したことから、酸化鉄含有粉（Ｃ）の配合量も十分であったと言える。 In Invention Example 1, the raw material blending ratio of the unfired agglomerated mineral is 7 mass% hydraulic binder, iron raw material for iron making (A1): 81 mass%, and iron oxide-containing powder (C1): 12 mass%. The unfired agglomerated mineral has sufficient strength in the cold by joining with the hydraulic binder (the amount of powder during transport is as small as 0.9 mass%). In addition, when looking at the operation of the blast furnace, the amount of dredging is large, the ratio of reducing material is low, and there is no blow-through phenomenon. This is presumably because the blended iron oxide-containing powder (C1) was sintered by being heated in a blast furnace, and high strength could be maintained even in the hot state. In addition, since the particle size distribution of the iron raw material for iron making (A) is 10 mass% or less, the blending amount of the iron oxide-containing powder (C) is preferably 10 mass% or more, but in the present invention example, 12 mass% is blended. Therefore, it can be said that the blending amount of the iron oxide-containing powder (C) was sufficient.
発明例２は、非焼成塊成鉱の原料配合割合を水硬性結合材：７mass％、製鉄用鉄原料(A2)：９０mass％、酸化鉄含有粉(C1)：３mass％としたものである。この非焼成塊成鉱は、水硬性結合材による接合で冷間における強度は十分（輸送時粉化量は０．９mass％と小さい）である。また、高炉の操業を見ると、出銑量も多く還元材比も低く、吹き抜け現象も起きていない。これは、配合した酸化鉄含有粉(C1)が高炉内で加熱されることにより焼結し、熱間においても高い強度が維持できたためであると考えられる。なお、酸化鉄含有粉（Ｃ）の配合量は、製鉄用鉄原料（Ａ）の粒度分布が４０μｍ以下が１０mass％以下であるため、２mass％以上が望ましいところ、本発明例では３mass％配合したことから、酸化鉄含有粉（Ｃ）の配合量も十分であったと言える。 In Invention Example 2, the raw material blending ratio of the unfired agglomerated mineral is 7 mass% hydraulic binder, 90 mass% iron raw material for iron making (A2), and 3 mass% iron oxide-containing powder (C1). The unfired agglomerated mineral has sufficient strength in the cold by joining with the hydraulic binder (the amount of powder during transport is as small as 0.9 mass%). In addition, when looking at the operation of the blast furnace, the amount of dredging is large, the ratio of reducing material is low, and there is no blow-through phenomenon. This is presumably because the blended iron oxide-containing powder (C1) was sintered by being heated in a blast furnace, and high strength could be maintained even in the hot state. In addition, since the particle size distribution of the iron raw material (A) for iron making is 10 mass% or less because the particle size distribution of the iron raw material for iron making (A) is 10 mass% or less, the blending amount of the iron oxide-containing powder (C) is desirably 2 mass% or more. Therefore, it can be said that the blending amount of the iron oxide-containing powder (C) was sufficient.
発明例３は、非焼成塊成鉱の原料配合割合を水硬性結合材：７mass％、製鉄用鉄原料(A1)：８５mass％、酸化鉄含有粉(C1)：８mass％としたものである。この非焼成塊成鉱は、水硬性結合材による接合で冷間における強度は十分（輸送時粉化量は０．９mass％と小さい）である。また、高炉の操業を見ると、発明例１や発明例２と比較するとやや劣るものの出銑量も多く還元材比も低く、吹き抜け現象も起きていない。これは、配合した酸化鉄含有粉(C1)が高炉内で加熱されることにより焼結し、熱間においても高い強度が維持できたためであると考えられる。なお、酸化鉄含有粉（Ｃ）の配合量は、製鉄用鉄原料（Ａ）の粒度分布が２０μｍ以下が１０mass％以下であるため、１０mass％以上が望ましいところ、本発明例では８mass％の配合であり、酸化鉄含有粉（Ｃ）の量がやや不足したものと考えられ、したがって、高炉操業成績が発明例１や発明例２に比較してやや劣ったものと考えられる。 In Invention Example 3, the raw material blending ratio of the non-fired agglomerated mineral is 7 mass% hydraulic binder, 85 mass% iron raw material for iron making (A1), and 8 mass% iron oxide-containing powder (C1). The unfired agglomerated mineral has sufficient strength in the cold by joining with the hydraulic binder (the amount of powder during transport is as small as 0.9 mass%). Further, when looking at the operation of the blast furnace, although it is slightly inferior to Invention Example 1 and Invention Example 2, the amount of brewing is large and the reducing material ratio is low, and the blow-through phenomenon does not occur. This is presumably because the blended iron oxide-containing powder (C1) was sintered by being heated in a blast furnace, and high strength could be maintained even in the hot state. In addition, since the particle size distribution of the iron raw material (A) for iron making is 10 mass% or less because the particle size distribution of the iron raw material for iron making (A) is 10 mass% or less, the blending amount of the iron oxide-containing powder (C) is preferably 8 mass% in the present invention example. Therefore, it is considered that the amount of the iron oxide-containing powder (C) is slightly insufficient, and therefore, the blast furnace operation results are considered to be slightly inferior to those of Invention Example 1 and Invention Example 2.
発明例４は、非焼成塊成鉱の原料配合割合を水硬性結合材：７mass％、製鉄用鉄原料(A2)：９２mass％、酸化鉄含有粉(C1)：１mass％としたものである。この非焼成塊成鉱は、水硬性結合材による接合で冷間における強度は十分（輸送時粉化量は０．９mass％と小さい）である。また、高炉の操業を見ると、発明例１や発明例２と比較するとやや劣るものの出銑量も多く還元材比も低く、吹き抜け現象も起きていない。これは、配合した酸化鉄含有粉(C1)が高炉内で加熱されることにより焼結し、熱間においても高い強度が維持できたためであると考えられる。なお、酸化鉄含有粉（Ｃ）の配合量は、製鉄用鉄原料（Ａ）の粒度分布が４０μｍ以下が１０mass％以下であるため、２mass％以上が望ましいところ、本発明例では１mass％の配合であり、酸化鉄含有粉（Ｃ）の量がやや不足したものと考えられ、したがって、高炉操業成績が発明例１や発明例２に比較してやや劣ったものと考えられる。 In Invention Example 4, the raw material blending ratio of the non-baked agglomerated mineral is 7 mass% for hydraulic binder, 92 mass% for ironmaking iron material (A2), and 1 mass% for iron oxide-containing powder (C1). The unfired agglomerated mineral has sufficient strength in the cold by joining with the hydraulic binder (the amount of powder during transport is as small as 0.9 mass%). Further, when looking at the operation of the blast furnace, although it is slightly inferior to Invention Example 1 and Invention Example 2, the amount of brewing is large and the reducing material ratio is low, and the blow-through phenomenon does not occur. This is presumably because the blended iron oxide-containing powder (C1) was sintered by being heated in a blast furnace, and high strength could be maintained even in the hot state. In addition, since the particle size distribution of the iron raw material (A) for iron making is 10 mass% or less because the particle size distribution of the iron raw material for iron making (A) is 10 mass% or less, the compounding amount of the iron oxide-containing powder (C) is preferably 2 mass% or more. Therefore, it is considered that the amount of the iron oxide-containing powder (C) is slightly insufficient, and therefore, the blast furnace operation results are considered to be slightly inferior to those of Invention Example 1 and Invention Example 2.
比較例１は、塊成鉱として、非焼成塊成鉱ではなく焼成塊成鉱（焼成ペレット）を用いた例である。焼成塊成鉱は高温で焼き固めているため、冷間における強度では非焼成ペレットよりも大きい（輸送時粉化量は０．６mass％と最小である）。また、高炉の操業を見ると、吹き抜け現象は起きておらず、概ね順調な操業が可能であったが、実施例に比較して出銑量がやや低下し、還元材比もやや上昇する結果となった。 Comparative Example 1 is an example in which not a non-calcined agglomerated mineral but a calcined agglomerated mineral (calcined pellet) is used as the agglomerated mineral. Since the calcined agglomerated ore is baked and hardened at a high temperature, the cold strength is larger than that of the non-fired pellets (the amount of powder during transport is 0.6 mass%, which is the smallest). Also, when looking at the operation of the blast furnace, there was no blow-through phenomenon, and it was possible to operate smoothly in general, but the amount of slag decreased slightly and the ratio of reducing material increased slightly compared to the examples. It became.
比較例２は、非焼成塊成鉱の原料配合割合を水硬性結合材：７mass％、製鉄用鉄原料(A1)：７８mass％、酸化鉄含有粉(C2)：１５mass％としたものである。この非焼成塊成鉱は、水硬性結合材による接合で冷間における強度は十分（輸送時粉化量は１．０mass％と小さい）である。一方、高炉の操業を見ると、発明例と比較して出銑量が大幅に低下し、還元材比も大きく上昇している。また、吹き抜け現象も９回／日と頻発している。これは、配合した酸化鉄含有粉（Ｃ）の粒度が粗く高炉内で加熱されても焼結しにくいため、高温雰囲気下でセメント水和物が分解すると強度が著しく低下し、高炉内の通気性が悪化したためであると考えられる。 In Comparative Example 2, the raw material blending ratio of the non-fired agglomerated mineral is 7 mass% hydraulic binder, iron raw material for iron making (A1): 78 mass%, and iron oxide-containing powder (C2): 15 mass%. This unfired agglomerated mineral has sufficient strength in the cold by joining with a hydraulic binder (the amount of powder during transport is as small as 1.0 mass%). On the other hand, when looking at the operation of the blast furnace, the amount of slag is greatly reduced and the ratio of reducing material is greatly increased as compared with the invention examples. Moreover, the blow-through phenomenon is frequently occurring 9 times / day. This is because the blended iron oxide-containing powder (C) has a coarse particle size and is difficult to sinter even if heated in a blast furnace. This is thought to be due to the deterioration of sex.
比較例３は、非焼成塊成鉱の原料配合割合を水硬性結合材：７mass％、製鉄用鉄原料(A1)：９３mass％とし、酸化鉄含有粉(Ｃ)は配合しなかった例である。この非焼成塊成鉱は、水硬性結合材による接合で冷間における強度は十分（輸送時粉化量は０．９０mass％と小さい）である。一方、高炉の操業を見ると、発明例と比較して出銑量が大幅に低下し、還元材比も大きく上昇している。また、吹き抜け現象も１２回／日と頻発している。これは、酸化鉄含有粉（Ｃ）を配合していないため、高温雰囲気下でセメント水和物が分解すると強度が著しく低下し、高炉内の通気性が悪化したためであると考えられる。 Comparative Example 3 is an example in which the raw material blending ratio of the unfired agglomerated mineral was 7 mass%, the iron raw material for iron making (A1): 93 mass%, and the iron oxide-containing powder (C) was not blended. . This unfired agglomerated mineral has sufficient strength in cold joining with a hydraulic binder (the amount of powder during transportation is as small as 0.90 mass%). On the other hand, when looking at the operation of the blast furnace, the amount of slag is greatly reduced and the ratio of reducing material is greatly increased as compared with the invention examples. Moreover, the blow-through phenomenon is frequently occurring at 12 times / day. This is presumably because the iron oxide-containing powder (C) was not blended, and therefore, when cement hydrate was decomposed in a high-temperature atmosphere, the strength was significantly reduced and the air permeability in the blast furnace was deteriorated.
［実施例２］
この実施例では、製鉄用鉄原料（Ａ）として、返鉱（粒径４ｍｍ以下）と鉄鉱石粉（平均粒径４０〜１００μｍ）を用いた。また、酸化鉄含有粉（Ｃ）としては鋼材酸洗ライン回収粉（酸化鉄含有量：９９．８９mass％，粒径１０μｍ以下の割合が９７．９mass％）を用いた。また、水硬性結合材（Ｂ）としては、ハイアルミナセメント、ポルトランドセメント、高炉水砕スラグ微粉末のいずれかを用いた。
[Example 2]
In this example, as the iron raw material (A) for iron making, return mineral (particle size of 4 mm or less) and iron ore powder (average particle size of 40 to 100 μm) were used. Moreover, steel material pickling line collection | recovery powder (Iron oxide content: 99.89 mass%, the ratio of a particle size of 10 micrometers or less is 97.9 mass%) was used as iron oxide containing powder (C). In addition, as the hydraulic binder (B), any of high alumina cement, Portland cement, and ground granulated blast furnace slag was used.
上記原料を表３，４に示した配合割合で適宜配合し、所定量の水を添加して、万能混練機にて６分間混練した。この混練物を３０×３０×３０ｍｍの型に流し込んで成型し、卓上バイブレーターにて１分間振動して脱泡した。この成型物を１日後に脱型した後、１１０℃×２４ｈの乾燥処理を行い、非焼成塊成鉱の成品を得た。その後、発明例１〜５及び比較例１，２の非焼成塊成鉱については８００℃×３ｈで、発明例６〜９については９００℃×３ｈで、各々コークスブリーズ中において還元焼成した。
各非焼成塊成鉱（乾燥体）について、常温中にて下降速度１ｍｍ／分で圧縮試験を行った。また、各非焼成塊成鉱の焼成体について、窒素５Ｌ／分を流しながら、焼成温度と同温度にて下降速度０．１ｍｍ／分で圧縮試験を行った。なお、目標強度は１ＭＰａとした。
以上の圧縮試験の結果を、各非焼成塊成鉱の配合割合とともに、表３および表４に示す。
The raw materials were appropriately blended at the blending ratios shown in Tables 3 and 4, a predetermined amount of water was added, and the mixture was kneaded for 6 minutes with a universal kneader. The kneaded product was poured into a 30 × 30 × 30 mm mold, molded, and defoamed by vibrating for 1 minute with a desktop vibrator. The molded product was demolded one day later, and then dried at 110 ° C. for 24 hours to obtain a non-fired agglomerated product. Thereafter, the non-fired agglomerates of Invention Examples 1 to 5 and Comparative Examples 1 and 2 were subjected to reduction firing in a coke breeze at 800 ° C. × 3 h and for Invention Examples 6 to 9 at 900 ° C. × 3 h.
Each non-fired agglomerated mineral (dried body) was subjected to a compression test at a descending speed of 1 mm / min at room temperature. Moreover, about the baked body of each non-baking agglomerated mineral, the compression test was done at the descent | fall speed | rate of 0.1 mm / min at the same temperature as baking temperature, flowing nitrogen 5L / min. The target strength was 1 MPa.
The result of the above compression test is shown in Table 3 and Table 4 together with the blending ratio of each non-fired agglomerated mineral.
表３，４において、本発明条件を満足し且つ返鉱（粒径４ｍｍ以下）と平均粒径４０〜１００μｍの鉄鉱石粉を併用することにより製鉄用鉄原料（Ａ）の粒度調整を行った発明例は、冷間及び熱間ともに十分な圧縮強度が得られている。
発明例６と発明例７はポルトランドセメントの配合量がそれぞれ４mass％と１０mass％の実施例であり、常温の圧縮強度はポルトランドセメント：１０mass％の発明例７の方が大きいが、熱間の圧縮強度は発明例６と発明例７でほぼ同等である。なお、発明例８はポルトランドセメント配合量が１２mass％であるが、熱間強度はポルトランドセメント配合量：１０mass％の発明例７とあまり変わらない。また、発明例９はポルトランドセメント配合量が少ない場合であるが、他の発明例に較べて常温強度が小さい。
In Tables 3 and 4, the present invention satisfied the conditions of the present invention, and the particle size of the iron raw material for iron making (A) was adjusted by using a return ore (particle size of 4 mm or less) and iron ore powder having an average particle size of 40 to 100 μm in combination. In the example, sufficient compressive strength is obtained both cold and hot.
Invention Example 6 and Invention Example 7 are examples in which the blending amounts of Portland cement are 4 mass% and 10 mass%, respectively, and the compressive strength at room temperature is higher in Invention Example 7 of Portland cement: 10 mass%, but hot compression The strength is almost equal between Invention Example 6 and Invention Example 7. Inventive Example 8 has a Portland cement blending amount of 12 mass%, but the hot strength is not much different from that of Invention Example 7 in which the Portland cement blending amount is 10 mass%. Inventive Example 9 is a case where the blending amount of Portland cement is small, but the room temperature strength is small as compared with other inventive examples.
これに対して、返鉱に水硬性結合材を加えただけの比較例１は、冷間及び熱間ともに圧縮強度が発明例に較べて大幅に劣っている。また、返鉱（粒径４ｍｍ以下）と平均粒径４０〜１００μｍの鉄鉱石粉を併用した製鉄用鉄原料に水硬性結合材を加えた比較例２も、熱間での圧縮強度が発明例に較べて大幅に劣っている。 On the other hand, the comparative example 1 which only added the hydraulic binder to the return ore is much inferior in compressive strength compared with the invention example both in cold and hot. Moreover, the comparative example 2 which added the hydraulic binder to the iron raw material for iron manufacture which used the iron ore powder of the average particle diameter of 40-100 micrometers in combination with a return ore (particle diameter of 4 mm or less) is also a hot compressive strength in invention example. It is far inferior in comparison.
ｘ，ｘ′ 非焼成塊成鉱
ａ 製鉄用鉄原料
ｂ 水硬性結合材
ｃ 酸化鉄含有粉
１ａ〜１ｃ 原料貯留槽
２，４，６ 原料搬送装置
３ 加湿混合機
５ 造粒機
７ 静置ヤード
x, x 'Non-calcined agglomerates a Iron raw materials for iron making b Hydraulic binders c Iron oxide-containing powders 1a to 1c Raw
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