JP2002241821A - Method for manufacturing sponge iron and method for manufacturing reduced iron powder - Google Patents
Method for manufacturing sponge iron and method for manufacturing reduced iron powderInfo
- Publication number
- JP2002241821A JP2002241821A JP2001036676A JP2001036676A JP2002241821A JP 2002241821 A JP2002241821 A JP 2002241821A JP 2001036676 A JP2001036676 A JP 2001036676A JP 2001036676 A JP2001036676 A JP 2001036676A JP 2002241821 A JP2002241821 A JP 2002241821A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- iron
- hematite
- iron oxide
- sponge iron
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 154
- 239000000843 powder Substances 0.000 title claims abstract description 135
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 53
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 title claims abstract description 12
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 74
- 239000011019 hematite Substances 0.000 claims abstract description 41
- 229910052595 hematite Inorganic materials 0.000 claims abstract description 41
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 claims abstract description 41
- 239000002245 particle Substances 0.000 claims abstract description 20
- 239000007787 solid Substances 0.000 claims abstract description 19
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 18
- 238000002156 mixing Methods 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 claims description 13
- 239000007864 aqueous solution Substances 0.000 claims description 5
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 claims description 5
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 239000000203 mixture Substances 0.000 abstract description 8
- 238000006722 reduction reaction Methods 0.000 description 21
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 11
- 235000011941 Tilia x europaea Nutrition 0.000 description 11
- 239000004571 lime Substances 0.000 description 11
- 239000007789 gas Substances 0.000 description 10
- 239000002994 raw material Substances 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 8
- 238000005245 sintering Methods 0.000 description 7
- 239000011812 mixed powder Substances 0.000 description 6
- 238000004663 powder metallurgy Methods 0.000 description 6
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 5
- 229910004298 SiO 2 Inorganic materials 0.000 description 5
- 238000010298 pulverizing process Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000000571 coke Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 3
- 239000003830 anthracite Substances 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000004438 BET method Methods 0.000 description 2
- 238000010744 Boudouard reaction Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000008186 active pharmaceutical agent Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- LFYJSSARVMHQJB-QIXNEVBVSA-N bakuchiol Chemical compound CC(C)=CCC[C@@](C)(C=C)\C=C\C1=CC=C(O)C=C1 LFYJSSARVMHQJB-QIXNEVBVSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- WMVRXDZNYVJBAH-UHFFFAOYSA-N dioxoiron Chemical compound O=[Fe]=O WMVRXDZNYVJBAH-UHFFFAOYSA-N 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 235000000396 iron Nutrition 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、海綿鉄および還元
鉄粉の製造に係り、とくに粉末冶金用鉄粉として好適な
低見掛け密度を有する還元鉄粉を能率良く製造する方法
に関する。TECHNICAL FIELD The present invention relates to the production of sponge iron and reduced iron powder, and more particularly to a method for efficiently producing reduced iron powder having a low apparent density suitable as iron powder for powder metallurgy.
【０００２】[0002]
【従来の技術】従来、粉末冶金用鉄粉として用いられる
海綿鉄は、例えば、図１に示すように、サガーと呼ばれ
る耐熱容器内に円筒状を呈するように、酸化鉄を、固体
還元剤に挟まれるように充填し、その耐熱容器をトンネ
ル炉を使って加熱することにより、酸化鉄を粗還元して
製造されていた。この海綿鉄はFe分が90〜97質量％であ
り、さらに高純度化のため粗粉砕されて、90メッシュ以
下の粗還元鉄粒子とされ、さらに、水素で代表される非
酸化性雰囲気中で仕上げ還元されて、最終的にFe分が9
9.5質量％以上の高純度の還元鉄粉とされる。一般に、
酸化鉄としては、鉄鉱石、ミルスケールが使用され、ま
た、固体還元剤としては、コークス等の炭素質粉と石灰
粉との混合物が使用されている。海綿鉄および還元鉄粉
の製造工程を図２に示す。2. Description of the Related Art Conventionally, sponge iron used as iron powder for powder metallurgy is prepared by converting iron oxide into a solid reducing agent so as to have a cylindrical shape in a heat-resistant container called sagar as shown in FIG. It was manufactured by filling it so as to be sandwiched and heating the heat-resistant container using a tunnel furnace to roughly reduce iron oxide. This sponge iron has a Fe content of 90 to 97% by mass, and is coarsely pulverized to obtain coarse reduced iron particles having a size of 90 mesh or less in order to further purify it. Finish reduction, finally Fe content 9
High-purity reduced iron powder of 9.5 mass% or more. In general,
Iron ore and mill scale are used as iron oxide, and a mixture of carbonaceous powder such as coke and lime powder is used as a solid reducing agent. FIG. 2 shows a process for producing sponge iron and reduced iron powder.
【０００３】一般に、海綿鉄を仕上げ還元して得られる
還元鉄粉は、粒子形状が不規則形状で多孔質であり、成
形性や焼結性に優れ、粉末冶金用原料として、アトマイ
ズ鉄粉とともに使用されている。また、還元鉄粉は、空
孔が多く、またアトマイズ鉄粉に比べると比表面積が大
きく、酸素との反応性が高く、カイロや脱酸素材などの
ような反応用鉄粉としても広く使用されている。[0003] In general, reduced iron powder obtained by finishing and reducing sponge iron has an irregular particle shape and is porous, has excellent moldability and sinterability, and is used as a raw material for powder metallurgy together with atomized iron powder. It is used. In addition, reduced iron powder has many pores, has a large specific surface area compared to atomized iron powder, has high reactivity with oxygen, and is widely used as an iron powder for reactions such as warmers and deoxidizing materials. ing.
【０００４】ミルスケールを粗還元して得られる海綿鉄
を、さらに仕上げ還元して得られる還元鉄粉は、一般に
純度が高いが、見掛け密度が2.40〜2.80Mg/m3 と比較的
高く、成形性が低いという問題があった。また、鉄鉱石
を粗還元して得られる海綿鉄を、さらに仕上げ還元して
得られる還元鉄粉は、見掛け密度が1.70〜2.50Mg/m3 と
低く、含油軸受用鉄粉として使用されているが、圧縮性
が低いという問題がある。また、鉄鉱石は、酸化鉄の純
度が低く、SiO2、Al2O3 等の脈石成分がおのおの１〜２
質量％、0.2 〜１質量％程度含有することが多く、この
SiO2、Al2O3 等が介在物として還元鉄粉中に残存し、軸
受の性能低下を招くという懸念もあった。[0004] Reduced iron powder obtained by further reducing the sponge iron obtained by roughly reducing the mill scale is generally high in purity, but has a relatively high apparent density of 2.40 to 2.80 Mg / m 3, and is compact. There was a problem that the property is low. Further, the sponge iron obtained by crude reduced iron ore is obtained by further finishing reduction reduction iron powder, the apparent density is as low as 1.70~2.50Mg / m 3, is used as the iron powder for oil retaining bearing However, there is a problem that the compressibility is low. Further, iron ore has low purity of iron oxide, and gangue components such as SiO 2 and Al 2 O 3 each have 1-2.
% By mass, and 0.2 to 1% by mass.
There has been a concern that SiO 2 , Al 2 O 3, and the like may remain in the reduced iron powder as inclusions, leading to a reduction in bearing performance.
【０００５】このような問題に対し、例えば、特開昭53
-26710号公報には、ミルスケール粉に５〜40重量％の鉄
鉱石を混合した原料を粗還元し海綿鉄となし、さらに該
海綿鉄を粉砕し、不純物を除去したのち、仕上げ還元
し、解砕して見掛け密度2.0 〜2.6 g/cm3 とする、成形
性および圧縮性に優れた粉末冶金用還元鉄粉の製造方法
が提案されている。To solve such a problem, see, for example,
No. -26710 discloses that a raw material obtained by mixing mill scale powder with 5 to 40% by weight of iron ore is roughly reduced to sponge iron, and the sponge iron is further pulverized to remove impurities, and then subjected to finish reduction. A method for producing reduced iron powder for powder metallurgy, which is crushed to have an apparent density of 2.0 to 2.6 g / cm 3 and has excellent moldability and compressibility, has been proposed.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、特開昭
53-26710号公報に記載された技術で製造された還元鉄粉
は、見掛け密度は確かに低くなるが、鉄鉱石を使用して
おり、依然として純度が低く、還元鉄粉中に介在物が残
存するという懸念が残されていた。本発明は、上記した
従来技術の問題を有利に解決し、純度が高く、見掛け密
度の低い還元鉄粉が得られる、海綿鉄および還元鉄粉の
製造方法を提案することを目的とする。SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
Reduced iron powder produced by the technique described in JP-A-53-26710 has apparently reduced apparent density, but uses iron ore, is still low in purity, and inclusions remain in the reduced iron powder. Concerns remained. An object of the present invention is to provide a method for producing sponge iron and reduced iron powder that advantageously solves the above-described problems of the prior art and that provides reduced iron powder having high purity and low apparent density.
【０００７】なお、本発明でいう「見掛け密度が低い」
鉄粉とは、見掛け密度が2.40Mg/m3以下である鉄粉を言
うものとする。また、本発明における見掛け密度は、日
本粉末冶金工業会規格 JPMA P06-1992に準拠して測定し
た値とする。In the present invention, "the apparent density is low".
Iron powder refers to iron powder having an apparent density of 2.40 Mg / m 3 or less. Further, the apparent density in the present invention is a value measured according to Japan Powder Metallurgy Industry Association Standard JPMA P06-1992.
【０００８】[0008]
【課題を解決するための手段】海綿鉄の生成反応は、次
の（１）〜（３）式に示される反応からなる。 CaCO3 →CaO ＋CO2 ……（１） CO2 ＋Ｃ→ 2CO ……（２） FeO ＋CO→ Fe ＋CO2 ……（３） まず、加熱により、（１）式にしたがい、固体還元剤層
内の石灰粉（CaCO3 ）が分解し、CO2 ガスを発生する。
このCO2 ガスは、（２）式のブドアール反応により固体
還元剤層内の炭素質粉（Ｃ）と反応してCOガスを発生す
る。このCOガスは、酸化鉄層内に拡散し、（３）式の反
応にしたがい、酸化鉄（FeO ）を還元し、海綿鉄（Fe）
を生成する。この時、同時に発生したCO2 ガスは、酸化
鉄層内から固体還元剤層まで拡散し、再度（２）式のブ
ドアール反応を起こし、COガスを発生させる。そして、
このCOガスは、また酸化鉄層内に拡散し、酸化鉄（Fe
O）を還元し、海綿鉄（Fe）を生成する。この酸化鉄の
還元反応と同時に、生成した鉄の焼結反応が進行する。The reaction for producing sponge iron consists of the reactions represented by the following equations (1) to (3). CaCO 3 → CaO + CO 2 (1) CO 2 + C → 2CO (2) FeO + CO → Fe + CO 2 (3) First, according to the formula (1), the inside of the solid reducing agent layer is heated. Lime powder (CaCO 3 ) is decomposed to generate CO 2 gas.
This CO 2 gas reacts with the carbonaceous powder (C) in the solid reducing agent layer by the Boudouard reaction of the formula (2) to generate CO gas. This CO gas diffuses into the iron oxide layer, reduces iron oxide (FeO 2) and reacts with sponge iron (Fe) according to the reaction of equation (3).
Generate At this time, the CO 2 gas generated at the same time diffuses from the inside of the iron oxide layer to the solid reducing agent layer, and again causes the Boudouard reaction of the formula (2) to generate CO gas. And
This CO gas also diffuses into the iron oxide layer, and the iron oxide (Fe
O) is reduced to produce sponge iron (Fe). Simultaneously with the reduction reaction of the iron oxide, the sintering reaction of the generated iron proceeds.
【０００９】本発明者らは、上記した課題を達成するた
めには、まず見掛け密度の低い塊状海綿鉄を生成するこ
とが肝要であると考え、海綿鉄の生成反応から考のえて
生成した鉄の焼結反応を抑制し、海綿鉄内部に空隙を多
く生成させるのがよいことに想到した。そして、かかる
考えのもとに、さらに鋭意研究した結果、本発明者ら
は、生成した鉄の焼結反応を抑制するためには、ミルス
ケール粉に微細なヘマタイト粉末を混合し粗還元して海
綿鉄とすることがよいことを見いだした。The inventors of the present invention consider that it is essential to first produce massive sponge iron having a low apparent density in order to achieve the above-mentioned object, and have considered the iron produced from the sponge iron formation reaction. It has been conceived that it is better to suppress the sintering reaction and to form many voids inside the sponge iron. Then, based on this idea, as a result of further intensive research, the present inventors have found that in order to suppress the sintering reaction of the generated iron, a fine hematite powder is mixed with the mill scale powder and roughly reduced. I found that sponge iron is good.
【００１０】本発明は、上記した知見に基づいて、さら
に検討し完成されたものである。すなわち、本発明は、
酸化鉄を、固体還元剤とともに加熱して、該酸化鉄を還
元して海綿鉄とする海綿鉄の製造方法において、前記酸
化鉄をヘマタイト粉末とミルスケール粉末との混合粉と
し、前記ヘマタイト粉末を２m2/g以上の比表面積を有す
る粉末とし、かつ該ヘマタイト粉末の混合量を、前記酸
化鉄の全量に対し、５〜45質量％とすることを特徴とす
る海綿鉄の製造方法であり、また、本発明では、前記ミ
ルスケール粉末が、平均粒径30μm 〜1 mmのミルスケー
ル粉末であることが好ましい。また、本発明では、前記
ヘマタイト粉末が、塩化鉄水溶液を酸化焙焼してなるヘ
マタイト粉末であることが好ましい。The present invention has been further studied and completed based on the above findings. That is, the present invention
Heating iron oxide together with a solid reducing agent, a method for producing sponge iron which reduces the iron oxide to sponge iron, wherein the iron oxide is a mixed powder of hematite powder and mill scale powder, and the hematite powder is A method for producing sponge iron, wherein the powder has a specific surface area of 2 m 2 / g or more, and the amount of the hematite powder is 5 to 45% by mass with respect to the total amount of the iron oxide. In the present invention, it is preferable that the mill scale powder is a mill scale powder having an average particle size of 30 μm to 1 mm. In the present invention, the hematite powder is preferably a hematite powder obtained by oxidizing and roasting an aqueous solution of iron chloride.
【００１１】また、本発明は、上記したいずれかの製造
方法で製造された海綿鉄を、粉砕後、還元性雰囲気中で
還元して鉄粉とすることを特徴とする還元鉄粉の製造方
法である。Further, the present invention provides a method for producing reduced iron powder, comprising crushing sponge iron produced by any of the above-mentioned production methods and reducing it in a reducing atmosphere to obtain iron powder. It is.
【００１２】[0012]
【発明の実施の形態】まず、本発明では、耐熱容器に、
酸化鉄と固体還元剤とを充填する。例えば、図１に示す
ような円筒状のサガーと呼ばれるSiＣ製の耐熱容器に、
固体還元剤層に挟まれるように酸化鉄層を充填するのが
好ましい。本発明では、酸化鉄として、ミルスケール粉
末とヘマタイト粉末とを混合した混合粉を用いる。DESCRIPTION OF THE PREFERRED EMBODIMENTS First, in the present invention, a heat-resistant container
Fill with iron oxide and solid reducing agent. For example, in a heat-resistant container made of SiC called a cylindrical sagar as shown in FIG.
It is preferable to fill the iron oxide layer so as to be sandwiched between the solid reducing agent layers. In the present invention, a mixed powder obtained by mixing a mill scale powder and a hematite powder is used as the iron oxide.
【００１３】ミルスケール粉末としては、熱延工程で発
生するミルスケールを用いるのが好ましい。また、ミル
スケール粉末は、平均粒径30μm 〜1 mmの粉末とするの
が好ましい。ミルスケール粉末の平均粒径が 1mmを超え
ると、海綿鉄を粉砕する過程で著しく生産性が低下す
る。一方、平均粒径が30μm 未満ではミルスケール粉末
の平均粒径が細かいほど、海綿鉄の生産性は向上する
が、ミルスケール粉末の粉砕コストがかさみ実際的では
ない。As the mill scale powder, it is preferable to use mill scale generated in the hot rolling step. The mill scale powder is preferably a powder having an average particle diameter of 30 μm to 1 mm. When the average particle size of the mill-scale powder exceeds 1 mm, the productivity is significantly reduced in the process of grinding sponge iron. On the other hand, if the average particle size is less than 30 μm, the finer the average particle size of the mill-scale powder is, the higher the productivity of sponge iron is, but the milling cost of the mill-scale powder is increased, which is not practical.
【００１４】なお、本発明でいう粉末の「平均粒径」
は、ふるい法（日本粉末冶金工業会規格 JPMA P02-199
2）で測定した重量での累積頻度50％の粒径を意味する
ものとする。酸化鉄粉末として、本発明では、上記した
ミルスケール粉末に加えて、ヘマタイト粉末を用いる。
ヘマタイト粉末は、比表面積が２m2/g以上の微細な微粉
末とする。ミルスケール粉末に加えて、微細なヘマタイ
ト粉末を混合することにより、最終製品である還元鉄粉
の見掛け密度が低くなる。この機構はつぎのように考え
られる。The "average particle size" of the powder referred to in the present invention
Is the sieving method (JPMA P02-199
It means the particle size of 50% of cumulative frequency by weight measured in 2). In the present invention, hematite powder is used as the iron oxide powder in addition to the above-mentioned mill scale powder.
The hematite powder is a fine powder having a specific surface area of 2 m 2 / g or more. By mixing fine hematite powder in addition to the mill scale powder, the apparent density of the reduced iron powder as the final product is reduced. This mechanism is considered as follows.
【００１５】微細なヘマタイト粉末は、ミルスケール粉
末とミルスケール粉末との間に存在し、ミルスケール粉
末が還元されて生成される鉄（ミルスケール粉末起因の
鉄）同士の焼結の進行を抑制する。ミルスケール粉末と
ヘマタイト粉末とは、粒子同士が接触しているため、ミ
ルスケール粉末起因の鉄とヘマタイト粉末起因の鉄とは
容易に焼結する。ミルスケール粉末起因の鉄同士の焼結
が抑制された結果生じる海綿鉄中の空隙が、その後の粗
粉砕、仕上げ還元、粉砕工程を経て還元鉄粉となったの
ちも、空隙として残存するため、見掛け密度が低下する
ものと推察される。The fine hematite powder is present between the mill scale powders and suppresses the progress of sintering of iron (iron derived from the mill scale powder) generated by reduction of the mill scale powder. I do. Since the particles of the mill scale powder and the hematite powder are in contact with each other, iron derived from the mill scale powder and iron derived from the hematite powder easily sinter. Since the voids in the sponge iron resulting from the suppression of sintering between the irons caused by the mill-scale powder are reduced iron powder after the subsequent coarse pulverization, finish reduction, and pulverization steps, since they remain as voids, It is presumed that the apparent density decreases.
【００１６】ヘマタイト粉末の比表面積が2 m2/g未満で
は、ヘマタイト粉末が粗大となり、ミルスケール起因の
鉄同士の焼結が有効に抑制されなくなり、還元鉄粉の見
掛け密度の顕著な低下が得られない。また、ヘマタイト
粉末の比表面積が10m2/gを超えると、ハンドリングが難
しくなるため、好ましくは比表面積が10m2/g以下の粉末
とするのが好ましい。なお、本発明でいう粉末の「比表
面積」は、吸着ガスとして窒素を用いたＢＥＴ法で測定
した値を使用するものとする。If the specific surface area of the hematite powder is less than 2 m 2 / g, the hematite powder becomes coarse, the sintering of iron due to mill scale cannot be effectively suppressed, and the apparent density of the reduced iron powder significantly decreases. I can't get it. Further, if the specific surface area of the hematite powder exceeds 10 m 2 / g, handling becomes difficult. Therefore, it is preferable that the powder has a specific surface area of 10 m 2 / g or less. The "specific surface area" of the powder used in the present invention is a value measured by a BET method using nitrogen as an adsorbed gas.
【００１７】酸化鉄の一部として、混合されるヘマタイ
ト粉末の量は、酸化鉄の全量に対し、５〜45質量％とす
る。ヘマタイト粉末の混合量が、５質量％未満では、最
終的に得られる還元鉄粉の見掛け密度が高くなる。一
方、ヘマタイト粉末の混合量が、45質量％を超えると、
還元速度が遅くなり海綿鉄の生産性が低下する。このた
め、ヘマタイト粉末の混合量は、酸化鉄の全量に対し、
５〜45質量％とした。The amount of hematite powder mixed as a part of the iron oxide is 5 to 45% by mass based on the total amount of the iron oxide. When the mixing amount of the hematite powder is less than 5% by mass, the apparent density of the finally obtained reduced iron powder becomes high. On the other hand, when the mixing amount of the hematite powder exceeds 45% by mass,
The reduction rate becomes slow, and the productivity of sponge iron decreases. For this reason, the mixing amount of hematite powder is based on the total amount of iron oxide.
The content was 5 to 45% by mass.
【００１８】本発明で、酸化鉄の一部として使用するヘ
マタイト粉末は、塩化鉄水溶液を酸化焙焼してなるヘマ
タイト粉末とするのが好ましい。塩化鉄水溶液を酸化焙
焼してなるヘマタイト粉末は、市販されており、市販品
をそのまま使用しても何ら問題がない。市販品、例えば
川崎製鉄製酸化鉄KH-N、KH-DH は、粒末の比表面積が２
〜５m2/gであり、また介在物として問題となるSiO2の含
有量が300 質量ppm 以下、Al2O3 の含有量が30質量ppm
以下と非常に低く、本発明の実施に好適である。In the present invention, the hematite powder used as a part of the iron oxide is preferably a hematite powder obtained by oxidizing and roasting an aqueous solution of iron chloride. Hematite powder obtained by oxidizing and roasting an aqueous solution of iron chloride is commercially available, and there is no problem even if a commercially available product is used as it is. Commercially available products such as iron oxide KH-N and KH-DH manufactured by Kawasaki Steel have a specific surface area of 2
５5 m 2 / g, and the content of SiO 2 , which is a problem as an inclusion, is 300 mass ppm or less, and the content of Al 2 O 3 is 30 mass ppm.
The following is very low, and is suitable for the practice of the present invention.
【００１９】なお、本発明では、酸化鉄として、ミルス
ケール粉末とヘマタイト粉末とに加えて、さらにマグネ
タイト粉末を混合した混合粉を用いてもよい。一方、固
体還元剤は、石灰粉（CaCO3 ）と炭素質粉（Ｃ）との混
合物を使用するのが好ましい。石灰粉は平均粒径が小さ
いほど短時間で分解し、CO2 ガスの発生量を高めること
になり（２）式のブドアール反応を促進させることにも
なり還元反応の促進に有利となる。なお、石灰粉の混合
量は、固体還元剤の合計量（石灰粉と炭素質粉との合計
量）に対し、５〜30質量％とするのが好ましい。In the present invention, a mixed powder obtained by further mixing a magnetite powder in addition to the mill scale powder and the hematite powder may be used as the iron oxide. On the other hand, as the solid reducing agent, it is preferable to use a mixture of lime powder (CaCO 3 ) and carbonaceous powder (C). The smaller the average particle size of lime powder is, the shorter it is decomposed, the more the amount of generated CO 2 gas is increased, and it promotes the Budoard reaction of the formula (2), which is advantageous for promoting the reduction reaction. The mixing amount of the lime powder is preferably 5 to 30% by mass based on the total amount of the solid reducing agent (the total amount of the lime powder and the carbonaceous powder).
【００２０】炭素質粉は、コークスあるいは無煙炭を用
いるのが好ましい。これらの混合したものを使用しても
何ら問題はない。なお、炭素質粉の平均粒径が小さいほ
ど還元反応が促進される。このため、炭素質粉の平均粒
径は10mm以下とするのが好ましい。また、炭素質粉の混
合量は、固体還元剤の合計量（石灰粉と炭素質粉との合
計量）に対し、70〜95質量％とするのが好ましい。It is preferable to use coke or anthracite as the carbonaceous powder. There is no problem with using a mixture of these. The reduction reaction is promoted as the average particle size of the carbonaceous powder is smaller. For this reason, the average particle size of the carbonaceous powder is preferably set to 10 mm or less. The mixing amount of the carbonaceous powder is preferably 70 to 95% by mass based on the total amount of the solid reducing agent (the total amount of the lime powder and the carbonaceous powder).
【００２１】上記したように酸化鉄（ミルスケール粉末
とヘマタイト粉末とを混合した混合粉）と固体還元剤を
充填された耐熱容器は、ついでトンネル炉等の加熱炉に
装入され、加熱される。なお、加熱温度は1000℃以上13
00℃以下とするのが好ましい。加熱により、還元反応が
進行し、酸化鉄が固体還元剤により還元されて海綿鉄が
生成する。As described above, the heat-resistant container filled with iron oxide (mixed powder obtained by mixing mill scale powder and hematite powder) and the solid reducing agent is then charged into a heating furnace such as a tunnel furnace and heated. . The heating temperature is over 1000 ℃ 13
The temperature is preferably set to 00 ° C. or lower. By the heating, the reduction reaction proceeds, and iron oxide is reduced by the solid reducing agent to generate sponge iron.
【００２２】加熱温度が1000℃未満では、酸化鉄の還元
が十分進まず、生成する海綿鉄の純度が低下する。一
方、1300℃を超えると、粗還元と同時に進行する海綿鉄
の焼結が過度に進み、硬くなり、その後の粗粉砕での電
力消費量が増加したり、粉砕工具の損耗が著しく、製造
コストが増加する。このため、加熱温度は1000〜1300℃
の範囲とするのが好ましい。なお、より好ましくは、10
50〜 1200 ℃である。When the heating temperature is lower than 1000 ° C., the reduction of iron oxide does not proceed sufficiently, and the purity of sponge iron produced decreases. On the other hand, if the temperature exceeds 1300 ° C, the sintering of sponge iron, which proceeds simultaneously with the coarse reduction, proceeds excessively and becomes hard, increasing the power consumption in the subsequent coarse pulverization, and significantly reducing the wear of the pulverization tools, resulting in a low production cost. Increase. For this reason, the heating temperature is 1000-1300 ℃
It is preferable to set it in the range. In addition, more preferably, 10
50-1200 ° C.
【００２３】加熱後、海綿鉄と固体還元剤とを分離して
取り出す。取り出された海綿鉄は、仕上げ還元のため、
90メッシュ以下程度までに粗粉砕され、粗還元鉄粒子と
される。ついで、粗還元鉄粒子は、還元性雰囲気の仕上
げ還元炉中で仕上げ還元され、さらに粉砕されて、還元
鉄粉とされる。After heating, the sponge iron and the solid reducing agent are separated and taken out. The sponge iron taken out is for finishing reduction,
Coarsely pulverized to about 90 mesh or less to obtain coarse reduced iron particles. Next, the coarse reduced iron particles are finish-reduced in a finishing reduction furnace in a reducing atmosphere, and are further pulverized into reduced iron powder.
【００２４】[0024]
【実施例】主原料の酸化鉄（ミルスケール粉末とヘマタ
イト粉末との混合粉）250 kg と、副原料の固体還元剤
190kg を、図１に示すように、円筒状サガー（SiC 製耐
熱容器）（φ400 ×1800H mm）に、副原料の固体還元層
が主原料の酸化鉄層を挟むように、充填した。[Example] 250 kg of iron oxide (mixed powder of mill scale powder and hematite powder) as main raw material and solid reducing agent as auxiliary raw material
As shown in FIG. 1, 190 kg was filled in a cylindrical sagar (heat-resistant container made of SiC) (φ400 × 1800 Hmm) such that the solid reduction layer of the auxiliary material sandwiched the iron oxide layer of the main material.
【００２５】主原料として使用した粉末の組成を表１に
示す。上記した組成の、ミルスケール粉末、ヘマタイト
粉末を、表２に示す混合比率で混合した混合粉を主原料
とした。ミルスケール粉末は、熱間圧延工程で発生した
スケールを乾燥し粉砕した粉末を使用した。また、ヘマ
タイト粉末は、市販されている、塩化鉄水溶液を酸化焙
焼してなるヘマタイト粉末（川崎製鉄製酸化鉄：商品名
「KH-DS 」、「KH-DC 」）を使用した。ヘマタイト粉末
の比表面積は吸着ガスを窒素とするＢＥＴ法に依った。
また、一部の試料では、これらヘマタイト粉末を800 ℃
で仮焼し、粉砕したヘマタイト粗粉（比表面積：0.5 m2
/g）をヘマタイト粉末として使用した。また、一部の試
料では、主原料として表１に示す組成の鉄鉱石粉末を使
用した。Table 1 shows the composition of the powder used as the main raw material. A mixed powder obtained by mixing a mill scale powder and a hematite powder having the above-described compositions at a mixing ratio shown in Table 2 was used as a main raw material. As the mill scale powder, a powder obtained by drying and pulverizing the scale generated in the hot rolling step was used. The hematite powder used was a commercially available hematite powder obtained by oxidizing and roasting an aqueous solution of iron chloride (iron oxide made by Kawasaki Steel: trade names “KH-DS” and “KH-DC”). The specific surface area of the hematite powder was determined by the BET method using nitrogen as the adsorbed gas.
Also, in some samples, these hematite powders
Hematite coarse powder (specific surface area: 0.5 m 2
/ g) was used as hematite powder. In some samples, iron ore powder having the composition shown in Table 1 was used as a main raw material.
【００２６】また、副原料である固体還元剤は、表２に
示す配合量の石灰粉、炭素質粉の混合物とした。石灰粉
は平均粒径80μm の石灰粉を、炭素質粉はコークスおよ
び／または無煙炭を用いた。コークスは平均粒径85μm
のもの、無煙炭は平均粒径2.4mm のものを使用した。副
原料は、表２に示すそれぞれの配合量となるように秤量
し、予め均一に混合しておいたものを使用した。The solid reducing agent as an auxiliary material was a mixture of lime powder and carbonaceous powder in the amounts shown in Table 2. The lime powder used was lime powder having an average particle size of 80 μm, and the carbonaceous powder used was coke and / or anthracite. Coke has an average particle size of 85 μm
And anthracite with an average particle size of 2.4 mm were used. The auxiliary raw materials were weighed so as to have the respective compounding amounts shown in Table 2 and used beforehand and uniformly mixed.
【００２７】ついで、図１に示すように、主原料および
副原料を充填した耐熱容器（サガー）を、加熱炉（還元
炉）に装入し、SiC 製のサガー蓋をしたのち、表２に示
す加熱温度（粗還元加熱温度）まで昇温した。なお、昇
温時間は20ｈとし、保持時間を44ｈとし、保持後冷却し
た。さらに、得られた海綿鉄を、90メッシュ以下まで粗
粉砕し、ついで露点40℃の水素雰囲気中で900 ℃×１ｈ
の仕上げ還元を施し、さらに粉砕して還元鉄粉とした。Next, as shown in FIG. 1, the heat-resistant container (sagar) filled with the main raw material and the auxiliary raw material was charged into a heating furnace (reduction furnace), and a SiC-made sagar lid was placed. The temperature was raised to the indicated heating temperature (rough reduction heating temperature). The heating time was set to 20 hours, the holding time was set to 44 hours, and cooling was performed after the holding. Further, the obtained sponge iron was coarsely pulverized to 90 mesh or less, and then 900 ° C. × 1 hour in a hydrogen atmosphere having a dew point of 40 ° C.
, And further pulverized into reduced iron powder.
【００２８】得られた還元鉄粉について、化学分析によ
り、SiO2含有量、Al2O3 含有量、酸素含有量を測定し
た。また、得られた還元鉄粉について、日本粉末冶金工
業会規格 JPMA P06-1992に準拠して見掛け密度を測定し
た。これらの結果を表２に示す。With respect to the obtained reduced iron powder, the content of SiO 2, the content of Al 2 O 3 and the content of oxygen were measured by chemical analysis. The apparent density of the obtained reduced iron powder was measured in accordance with Japan Powder Metallurgy Industry Association Standard JPMA P06-1992. Table 2 shows the results.
【００２９】[0029]
【表１】 [Table 1]
【００３０】[0030]
【表２】 [Table 2]
【００３１】本発明例は、2.0 〜2.4 Mg/m3 と、従来例
（試料No.8、No.9）に比べ低い見掛け密度を有してい
る。また、本発明例は、いずれもSiO2、Al2O3 量が従来
例（試料No.9）に比べ少なく、高純度である。一方、ヘ
マタイト粉末の比表面積が本発明の範囲を低く外れる比
較例（試料No.10 ）は、還元鉄粉の見掛け密度が2.57Mg
/m3 と高くなっている。また、ヘマタイト粉末の混合量
が本発明の範囲を高く外れる比較例（試料No.11 ）は、
還元速度が遅く、還元不足となり、酸素量が高くなって
いる。The example of the present invention has an apparent density of 2.0 to 2.4 Mg / m 3 , which is lower than that of the conventional examples (samples No. 8 and No. 9). In addition, all of the examples of the present invention have smaller amounts of SiO 2 and Al 2 O 3 than the conventional example (sample No. 9), and have high purity. On the other hand, in the comparative example (sample No. 10) in which the specific surface area of the hematite powder was out of the range of the present invention, the apparent density of the reduced iron powder was 2.57Mg.
/ m 3 is high. A comparative example (sample No. 11) in which the mixing amount of hematite powder is out of the range of the present invention is as follows.
The reduction rate is low, the reduction is insufficient, and the amount of oxygen is high.
【００３２】[0032]
【発明の効果】以上のように、本発明によれば、従来に
くらべ、高純度で、低見掛け密度を有する海綿鉄、還元
鉄粉が、安価に供給でき、産業上格段の効果を奏する。As described above, according to the present invention, sponge iron and reduced iron powder having a higher purity and a lower apparent density can be supplied at lower cost than in the past, and the industrial effect is remarkably improved.
【図１】円筒状の耐熱容器への、炭素質粉および石灰粉
と、酸化鉄との充填方法の一例を示す説明図である。FIG. 1 is an explanatory view showing an example of a method of filling a carbon heat-resistant container with carbonaceous powder and lime powder and iron oxide.
【図２】海綿鉄、還元鉄粉の製造工程の一例を示す説明
図である。FIG. 2 is an explanatory diagram showing an example of a process for producing sponge iron and reduced iron powder.
フロントページの続き (72)発明者 杉原 裕 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社千葉製鉄所内 Ｆターム(参考） 4K012 DA05 DA08 DA09 4K017 AA01 BA06 DA09 EK08 4K018 AA24 BA14 BB04 BC12 BD10 KA70 Continuation of the front page (72) Inventor Hiroshi Sugihara 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture F-term in the Chiba Works, Chiba Works 4K012 DA05 DA08 DA08 DA09 4K017 AA01 BA06 DA09 EK08 4K018 AA24 BA14 BB04 BC12 BD10 KA70
Claims (4)
て、該酸化鉄を還元して海綿鉄とする海綿鉄の製造方法
において、前記酸化鉄をヘマタイト粉末とミルスケール
粉末との混合粉とし、前記ヘマタイト粉末を２m2/g以上
の比表面積を有する粉末とし、かつ該ヘマタイト粉末の
混合量を、前記酸化鉄の全量に対し、５〜45質量％とす
ることを特徴とする海綿鉄の製造方法。1. A method for producing sponge iron by heating iron oxide together with a solid reducing agent to reduce the iron oxide into sponge iron, wherein the iron oxide is mixed with a hematite powder and a mill scale powder. The hematite powder is a powder having a specific surface area of 2 m 2 / g or more, and the mixing amount of the hematite powder is 5 to 45% by mass with respect to the total amount of the iron oxide. Production method.
m 〜1 mmのミルスケール粉末であることを特徴とする請
求項１に記載の海綿鉄の製造方法。2. The mill scale powder has an average particle size of 30 μm.
The method for producing sponge iron according to claim 1, wherein the powder is a mill scale powder having a diameter of m to 1 mm.
酸化焙焼してなるヘマタイト粉末であることを特徴とす
る請求項１または２に記載の海綿鉄の製造方法。3. The method for producing sponge iron according to claim 1, wherein the hematite powder is a hematite powder obtained by oxidizing and roasting an aqueous solution of iron chloride.
造方法で製造された海綿鉄を、粉砕後、還元性雰囲気中
で還元して鉄粉とすることを特徴とする還元鉄粉の製造
方法。4. A method of reducing iron powder, comprising crushing sponge iron produced by the production method according to claim 1 and reducing it in a reducing atmosphere to form iron powder. Production method.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001036676A JP3721993B2 (en) | 2001-02-14 | 2001-02-14 | Method for producing sponge iron and reduced iron powder |
| PCT/JP2002/001175 WO2002064844A1 (en) | 2001-02-14 | 2002-02-13 | Method for producing sponge iron, and reduced iron powder and method for production thereof |
| CNB028002970A CN1201021C (en) | 2001-02-14 | 2002-02-13 | Method for producing sponge iron, and reduced iron powder and method for production thereof |
| US10/257,187 US6918945B2 (en) | 2001-02-14 | 2002-02-13 | Method for producing sponge iron, and reduced iron powder and method for production thereof |
| CA 2404607 CA2404607A1 (en) | 2001-02-14 | 2002-02-13 | Method for manufacturing sponge iron, reduced iron powder, and method for manufacturing the same |
| SE0202977A SE524681C2 (en) | 2001-02-14 | 2002-10-10 | Method of making iron sponge, and making iron powder thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001036676A JP3721993B2 (en) | 2001-02-14 | 2001-02-14 | Method for producing sponge iron and reduced iron powder |
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| JP2002241821A true JP2002241821A (en) | 2002-08-28 |
| JP3721993B2 JP3721993B2 (en) | 2005-11-30 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8518146B2 (en) | 2009-06-29 | 2013-08-27 | Gb Group Holdings Limited | Metal reduction processes, metallurgical processes and products and apparatus |
| JP2013204075A (en) * | 2012-03-28 | 2013-10-07 | Taiwan Powder Technologies Co Ltd | Method for producing fine reduced iron powder |
| WO2015004880A1 (en) * | 2013-07-09 | 2015-01-15 | Ｊｆｅスチール株式会社 | Iron powder for bearing and method for producing iron powder for bearing |
| JP2023005342A (en) * | 2021-06-29 | 2023-01-18 | Ｄｏｗａエレクトロニクス株式会社 | Iron powder for deoxidizer |
-
2001
- 2001-02-14 JP JP2001036676A patent/JP3721993B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8518146B2 (en) | 2009-06-29 | 2013-08-27 | Gb Group Holdings Limited | Metal reduction processes, metallurgical processes and products and apparatus |
| JP2013204075A (en) * | 2012-03-28 | 2013-10-07 | Taiwan Powder Technologies Co Ltd | Method for producing fine reduced iron powder |
| WO2015004880A1 (en) * | 2013-07-09 | 2015-01-15 | Ｊｆｅスチール株式会社 | Iron powder for bearing and method for producing iron powder for bearing |
| JPWO2015004880A1 (en) * | 2013-07-09 | 2017-03-02 | Ｊｆｅスチール株式会社 | Iron powder for bearings and method for producing iron powder for bearings |
| JP2023005342A (en) * | 2021-06-29 | 2023-01-18 | Ｄｏｗａエレクトロニクス株式会社 | Iron powder for deoxidizer |
| JP7329563B2 (en) | 2021-06-29 | 2023-08-18 | Ｄｏｗａエレクトロニクス株式会社 | Iron powder for deoxidizer |
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