JPH01290701A - Production of reformed iron powder - Google Patents
Production of reformed iron powderInfo
- Publication number
- JPH01290701A JPH01290701A JP63121512A JP12151288A JPH01290701A JP H01290701 A JPH01290701 A JP H01290701A JP 63121512 A JP63121512 A JP 63121512A JP 12151288 A JP12151288 A JP 12151288A JP H01290701 A JPH01290701 A JP H01290701A
- Authority
- JP
- Japan
- Prior art keywords
- iron powder
- layer
- converter
- obtd
- surface layer
- 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.)
- Pending
Links
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 57
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 239000002344 surface layer Substances 0.000 claims abstract description 16
- 239000000428 dust Substances 0.000 claims abstract description 13
- 238000000227 grinding Methods 0.000 claims abstract description 4
- 230000001590 oxidative effect Effects 0.000 claims abstract description 3
- 239000010410 layer Substances 0.000 abstract description 25
- 238000005245 sintering Methods 0.000 abstract description 9
- 239000002994 raw material Substances 0.000 abstract description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 7
- 229910052799 carbon Inorganic materials 0.000 abstract description 7
- 230000003647 oxidation Effects 0.000 abstract description 7
- 238000007254 oxidation reaction Methods 0.000 abstract description 7
- 239000007787 solid Substances 0.000 abstract description 5
- 239000011800 void material Substances 0.000 abstract 1
- 239000000843 powder Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005261 decarburization Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000004663 powder metallurgy Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000010301 surface-oxidation reaction Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009415 formwork Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000006249 magnetic particle Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000010959 steel Substances 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
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、転炉で発生したダストから回収された鉄粉を
改質し、焼結性に優れた原料を製造する方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a raw material with excellent sinterability by modifying iron powder recovered from dust generated in a converter.
焼結原料の鉄粉としては、鉄鉱石、ミルスケール等を還
元することにより得られた還元鉄粉と、溶鋼を霧化して
粒状にしたアトマイズド鉄粉が使用されている。As the iron powder used as the raw material for sintering, reduced iron powder obtained by reducing iron ore, mill scale, etc., and atomized iron powder obtained by atomizing molten steel into granules are used.
このうち、還元鉄粉は、大きな比表面積をもっており、
優れた焼結性を示す。しかし、多孔質構造のために、型
枠に充填して成形するときスプリングバックがあること
や、焼結時に収縮が大きいこと等が原因して、焼結製品
の寸法精度が低くなる。また、鉄粉相互の間の凝集力が
小さく、内部の空隙を完全に無くすことが困難なため、
焼結体の強度が劣りがちである。他方、アトマイズド鉄
粉は、内部が中実であることから型枠に対する充填が容
易に行われ、得られた焼結体の寸法精度は優れたものと
なる。しかし、このアトマイズド鉄粉は、比表面積が小
さなことから、表面活性、焼結性等に劣る。Among these, reduced iron powder has a large specific surface area,
Shows excellent sinterability. However, due to the porous structure, the dimensional accuracy of the sintered product decreases due to springback when it is filled into a mold and molded, and large shrinkage during sintering. In addition, the cohesive force between iron powder is small and it is difficult to completely eliminate internal voids.
The strength of the sintered body tends to be poor. On the other hand, since the atomized iron powder has a solid interior, it can be easily filled into a mold, and the resulting sintered body has excellent dimensional accuracy. However, since this atomized iron powder has a small specific surface area, it is inferior in surface activity, sinterability, etc.
ところで、転炉等の冶金用炉から排出されたダストを成
分毎に分別し、これらの成分を有用な資源として再利用
することが行われている。このような再生資源として、
鉄粉がある。この鉄粉は、たとえば転炉で発生したダス
トをベンチュリースフラッパ等の湿式分級機で排ガスと
分離し、そのダストから鉄分を磁選し、摩鉱により表面
酸化層を剥離することによって製造している（特開昭５
４−１２７８０４号公報、特開昭５４−１２７８１０号
公報等参照）。Incidentally, dust discharged from a metallurgical furnace such as a converter is separated into its components, and these components are reused as useful resources. As such recycled resources,
There is iron powder. This iron powder is manufactured by, for example, separating the dust generated in a converter from the exhaust gas using a wet classifier such as a Venturi flapper, magnetically separating the iron from the dust, and removing the surface oxidized layer by grinding. (Unexamined Japanese Patent Publication No. 5
4-127804, JP-A-54-127810, etc.).
このようにして転炉で発生したダストから得られた鉄粉
は、ショツトブラスト用、磁粉探傷用。The iron powder obtained from the dust generated in the converter is used for shot blasting and magnetic particle testing.
粉末冶金用鉄粉等の用途に使用されている。しかし、こ
れを粉末冶金用の原料として使用する場合、その特性が
アトマイズド鉄粉に比較的近く、焼結性に劣るものであ
る。また、そのままでは、炭素含有量が高く、得られた
焼結体に対する加工性及び材料強度自体等に問題がある
。It is used for applications such as iron powder for powder metallurgy. However, when this is used as a raw material for powder metallurgy, its properties are relatively similar to those of atomized iron powder, and its sinterability is poor. In addition, if left as is, the carbon content is high and there are problems with the workability of the obtained sintered body and the material strength itself.
そこで、本発明は、転炉ダストから得られた鉄粉の表面
状態を改質することによって、型枠に対する充填性、焼
結性等が良好で、寸法精度、焼結強度に優れた焼結体を
製造することができる改メ鉄粉を得ることを目的とする
。Therefore, by modifying the surface condition of iron powder obtained from converter dust, the present invention aims to produce a sintered powder that has good filling properties in formwork, sinterability, etc., and has excellent dimensional accuracy and sintering strength. The purpose is to obtain modified iron powder that can be used to produce iron powder.
本発明の改質鉄粉の製造方法は、その目的を達成するた
めに、転炉で発生したダストから分離・摩鉱して得られ
た鉄粉の表面層を酸化し、次いで該表面層を還元するこ
とを特徴とする。In order to achieve its purpose, the method for producing modified iron powder of the present invention oxidizes the surface layer of iron powder obtained by separating and grinding the dust generated in a converter, and then oxidizes the surface layer. It is characterized by giving back.
転炉ダストから得られた鉄粉は、第１図（ａ）に示すよ
うに比較的球状に近い形状になっている。そして、この
鉄粉１は、内部と同様に緻密で金属鉄を主成分とする表
面層をもっており、反応性が悪い。また、球表面の平滑
な鉄粉は、充填圧着成形時に各粒子間の結合が悪く、成
型性は皆無に等しい。第１表は、この鉄粉の組成の一例
を示すものである。The iron powder obtained from the converter dust has a relatively spherical shape as shown in FIG. 1(a). The iron powder 1 has a surface layer that is dense and mainly composed of metallic iron like the inside, and has poor reactivity. In addition, iron powder with a smooth spherical surface has poor bonding between particles during filling and compression molding, resulting in almost no moldability. Table 1 shows an example of the composition of this iron powder.
第 １ 表
（単位：重量％）
この鉄粉ｌを酸化すると、第１図（ｂ）に示すように表
面酸化層２が形成する。しかし、この表面酸化層２に覆
われた内層３は、緻密なままの状態である。この酸化工
程において、鉄粉１に含まれている炭素は、Ｆｅ＋Ｏ→
ＦｅＯの反応を介して、２ Ｆ ｅ Ｏ＋Ｃ−ＣＯ２の
反応に従って脱炭される。Table 1 (Unit: Weight %) When this iron powder 1 is oxidized, a surface oxidation layer 2 is formed as shown in FIG. 1(b). However, the inner layer 3 covered with this surface oxidized layer 2 remains dense. In this oxidation process, the carbon contained in the iron powder 1 changes from Fe+O→
Through the reaction of FeO, it is decarburized according to the reaction of 2 Fe O + C-CO2.
この表層における脱炭反応によって該表層の炭素濃度は
極度に低下するため、内層部から炭素が拡散されつつ順
次内層も脱炭される。Since the carbon concentration in the surface layer is extremely reduced by this decarburization reaction in the surface layer, the inner layer is also gradually decarburized while carbon is diffused from the inner layer.
ついで、表面酸化層２を還元すると、第１図（Ｃ）に示
すように、空隙率の高い多孔質表面層４が形成される。Then, when the surface oxidized layer 2 is reduced, a porous surface layer 4 with a high porosity is formed as shown in FIG. 1(C).
このような酸化・還元工程によって、表面層のみが多孔
質であり、内部が中実となった鉄粉１が得られる。この
鉄粉ｌは、前述した還元鉄粉及びアトマイズド鉄粉双方
がもつ長所を兼ね備えており、優れた焼結原料として凛
用される。Through such an oxidation/reduction step, iron powder 1 is obtained in which only the surface layer is porous and the inside is solid. This iron powder 1 has the advantages of both the reduced iron powder and the atomized iron powder described above, and can be used as an excellent sintering raw material.
また、第２表に示すように炭素含有量も低いものとなっ
ているため、この原料から焼結して得られた製品の加工
性も優れたものとなる。Furthermore, as shown in Table 2, since the carbon content is low, the workability of products obtained by sintering this raw material is also excellent.
第 ２ 表
（単位：重量％）
なお、酸化工程で形成する表面酸化層２は、鉄粉１の重
量を基準として、２〜３０％の割合で設けるが、好まし
くは５〜２５％が良い。表面酸化層２の生成率をこの範
囲に維持しておくとき、中実の内層３及び多孔質表面層
４両者の特徴が活かされる。これに対して、表面酸化層
２の生成率が２％未満では、鉄粉１表面の活性化が不充
分であり、焼結性がさほど向上しない。また、表面酸化
層２の生成率が３０％を超えるとき、内層３の割合が小
さくなり、還元鉄粉の欠点が現れるとともに処理時間、
処理コストともに悪化する。この表面酸化層２の生成率
は、酸化工程時の加熱温度、加熱時間、雰囲気ガスの酸
化力等によって調整することができる。Table 2 (Unit: Weight %) The surface oxidized layer 2 formed in the oxidation step is provided at a ratio of 2 to 30%, preferably 5 to 25%, based on the weight of the iron powder 1. When the production rate of the surface oxidized layer 2 is maintained within this range, the characteristics of both the solid inner layer 3 and the porous surface layer 4 are utilized. On the other hand, if the generation rate of the surface oxidized layer 2 is less than 2%, the activation of the surface of the iron powder 1 is insufficient, and the sinterability is not improved much. Moreover, when the generation rate of the surface oxidized layer 2 exceeds 30%, the proportion of the inner layer 3 becomes small, and the disadvantages of reduced iron powder appear, and the processing time increases.
Both processing costs will worsen. The production rate of this surface oxidized layer 2 can be adjusted by adjusting the heating temperature, heating time, oxidizing power of the atmospheric gas, etc. during the oxidation step.
以下、実施例により本発明の特徴を具体的に説明する。 Hereinafter, the features of the present invention will be specifically explained with reference to Examples.
第１表に示した組成をもつ鉄粉を、Ｎ２６０％。Iron powder having the composition shown in Table 1 was mixed with 60% N2.
０２５％、 Ｈ２Ｏ３５％の酸化雪囲気で６５０℃に
加熱し、表面酸化層を形成した。このとき、加熱時間を
変更することにより、表面酸化層２の生成率を５〜３０
％の範囲に調整した。次いで、この鉄粉をＮ２２０％、
Ｎ２７５％、００５％の還元３囲気で５５０℃に加
熱することにより、表面酸化層を還元して多孔質表面層
を形成した。前述の第２表は、この還元処理された状態
での鉄粉の組成を示す。The sample was heated to 650° C. in an oxidized snow atmosphere containing 0.25% H2O and 35% H2O to form a surface oxidation layer. At this time, by changing the heating time, the generation rate of the surface oxidized layer 2 can be increased from 5 to 30%.
Adjusted to % range. Next, this iron powder was mixed with 20% N2,
The surface oxide layer was reduced by heating to 550° C. in a reducing atmosphere of 75% N2 and 005% to form a porous surface layer. Table 2 above shows the composition of the iron powder in the reduced state.
このようにして処理された鉄粉を６０ Ｘ２５ Ｘ１５
＋ｎｍの内部空間をもつ型枠に充填し、加圧・成形した
後、８００ ℃で焼結した。The iron powder treated in this way is 60 x 25 x 15
The material was filled into a mold having an internal space of +nm, pressed and molded, and then sintered at 800°C.
第２図は、表面酸化層の生成率が鉄粉の焼結体の寸法精
度に与える影響を表したグラフである。FIG. 2 is a graph showing the influence of the production rate of the surface oxidized layer on the dimensional accuracy of the sintered body of iron powder.
ここで寸法精度は成形原寸法を１としてその差を指数で
表示した。この図から明らかなように、多孔質表面層の
生成により、正確な形状をもつ焼結体を容易にａｌ！造
することができた。Here, the dimensional accuracy is expressed as an index based on the difference between the original molding dimensions and 1. As is clear from this figure, the formation of a porous surface layer makes it easy to form a sintered body with an accurate shape. I was able to build it.
また、得られた焼結体は、炭素含有量の低下に伴いその
硬度が低下し、加工性に優れたものであった。これに対
し、転炉ダストから得られた鉄粉を直接焼結して得られ
た焼結体は、硬度が極めて高く、その加工は極めて困難
であった。Furthermore, the hardness of the obtained sintered body decreased as the carbon content decreased, and it had excellent workability. On the other hand, sintered bodies obtained by directly sintering iron powder obtained from converter dust have extremely high hardness and are extremely difficult to process.
この燃結性の向上理由としては、多孔質表面が相互にか
らみ合って強結合を形成しており、この多孔面が容易に
結合することから鉄粉自体の燃結性も大巾に向上すると
ともに、その特性も良好なものにできる。The reason for this improvement in sinterability is that the porous surfaces are intertwined with each other to form strong bonds, and since these porous surfaces are easily bonded together, the sinterability of the iron powder itself is also greatly improved. At the same time, its characteristics can also be improved.
以上に説明したように、本発明においては、転炉ダスト
から得られた鉄粉の表面を多孔質とすることにより、溶
結性に優れた原料が得られる。また、内部が質量の大き
な中実であるため、強度の大きな焼結体を製造すること
ができる。更に、酸化工程で脱炭も同時に行われるため
、焼結体の加工性も改善される。このように、本発明に
よるとき、焼結原料として好適な鉄粉が得られる。As explained above, in the present invention, by making the surface of iron powder obtained from converter dust porous, a raw material with excellent weldability can be obtained. Moreover, since the inside is solid with a large mass, a sintered body with high strength can be manufactured. Furthermore, since decarburization is simultaneously performed in the oxidation step, the workability of the sintered body is also improved. Thus, according to the present invention, iron powder suitable as a sintering raw material is obtained.
第１図は酸化・還元によって変化する鉄粉の表面状態を
示し、第２図は寸法精度に与える表面酸化層生成率の影
響を表したグラフである。
１：鉄粉 ２：表面酸化層
３：内層 ４：多孔質表面層FIG. 1 shows the surface condition of iron powder that changes due to oxidation and reduction, and FIG. 2 is a graph showing the influence of the surface oxide layer formation rate on dimensional accuracy. 1: Iron powder 2: Surface oxidized layer 3: Inner layer 4: Porous surface layer
Claims (1)
鉄粉の表面層を酸化し、次いで該表面層を還元すること
を特徴とする改質鉄粉の製造方法。1. A method for producing modified iron powder, which comprises oxidizing the surface layer of iron powder obtained by separating and grinding dust generated in a converter, and then reducing the surface layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63121512A JPH01290701A (en) | 1988-05-17 | 1988-05-17 | Production of reformed iron powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63121512A JPH01290701A (en) | 1988-05-17 | 1988-05-17 | Production of reformed iron powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01290701A true JPH01290701A (en) | 1989-11-22 |
Family
ID=14813036
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63121512A Pending JPH01290701A (en) | 1988-05-17 | 1988-05-17 | Production of reformed iron powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01290701A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1076234C (en) * | 1995-12-09 | 2001-12-19 | 樊枝花钢铁(集团)公司钢铁研究院 | Method of preparing iron powder and its products by using steelmaking converter smoke or slude |
| CN1087984C (en) * | 1999-03-08 | 2002-07-24 | 中南工业大学 | Method for preparing iron powder used in metallurgy from converter mud |
| US11427877B2 (en) * | 2017-09-21 | 2022-08-30 | Nucor Corporation | Direct reduced iron (DRI) heat treatment, products formed therefrom, and use thereof |
-
1988
- 1988-05-17 JP JP63121512A patent/JPH01290701A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1076234C (en) * | 1995-12-09 | 2001-12-19 | 樊枝花钢铁(集团)公司钢铁研究院 | Method of preparing iron powder and its products by using steelmaking converter smoke or slude |
| CN1087984C (en) * | 1999-03-08 | 2002-07-24 | 中南工业大学 | Method for preparing iron powder used in metallurgy from converter mud |
| US11427877B2 (en) * | 2017-09-21 | 2022-08-30 | Nucor Corporation | Direct reduced iron (DRI) heat treatment, products formed therefrom, and use thereof |
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