JP4360117B2 - Method for manufacturing roadbed material - Google Patents
Method for manufacturing roadbed material Download PDFInfo
- Publication number
- JP4360117B2 JP4360117B2 JP2003130480A JP2003130480A JP4360117B2 JP 4360117 B2 JP4360117 B2 JP 4360117B2 JP 2003130480 A JP2003130480 A JP 2003130480A JP 2003130480 A JP2003130480 A JP 2003130480A JP 4360117 B2 JP4360117 B2 JP 4360117B2
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- JP
- Japan
- Prior art keywords
- slag
- scale
- reduced
- roadbed
- carbon source
- 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.)
- Expired - Fee Related
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Classifications
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- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Curing Cements, Concrete, And Artificial Stone (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Processing Of Solid Wastes (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、アーク炉製鋼の副生物である還元スラグを使用して路盤材を製造する方法に関し、あわせて、鋼の加工工程で発生するスケールの処理方法を提案する。
【０００２】
【従来の技術】
よく知られているように、アーク炉製鋼の副生物であるスラグには、酸化精錬期に発生する酸化スラグと、還元精錬期に発生する還元スラグとがあり、ともに路盤材として利用されている。しかし、これらのスラグは多量のＣａＯを含有するから、それが水を吸ってＣａ(ＯＨ)2となるときに、粉化する。そこで、粉化による弊害を防ぐため、スラグを高い湿度と温度との条件下におく、「エージング」と呼ばれる処理を施さなければ、使用できない。粉化の程度は、酸化スラグはそれほどでないが、還元スラグは著しく、酸化スラグの３〜４倍に相当する多量のスチームを消費して、エージングを行なっているのが現状である。
【０００３】
一方、鋼の圧延や鍛造などの熱間加工を行なうと、高温の素材の表面が酸化して剥落した、「スケール」が発生する。その成分はほぼＦｅＯであるから、高炉製銑の設備があればそこで製鉄原料として再利用することができ、そのように処理されている場合も少なくない。しかし、近くに高炉がない場合は利用が困難であり、製鉄所まで輸送することは、もちろん製鉄のコストに影響し、処理方法としては不利になる。廃棄処分をするとなれば、環境への影響を考慮しなければならず、結局コストがかかる。
【０００４】
発明者らは、酸化スラグが多量のＦｅＯを含有しているという点で、スケールと共通であることに着目し、還元スラグとスケールとを一体にすることによって、酸化スラグに近い成分組成をもった材料ができるはずであると考え、アーク炉において還元スラグとスケールとをともに溶融したところ、期待どおりの合成スラグが得られ、これが路磐材として有用であることが確認された。
【０００５】
【発明が解決しようとする課題】
本発明の目的は、上述した発明者らの知見を活用し、還元スラグからエージングの負担が軽い合成スラグを製造して、それを路盤材に使用する方法を提供し、あわせてスケールを処分する好適な途を提供することにある。
【０００６】
【課題を解決するための手段】
上記の目的を達成する本発明の路盤材の製造方法は、アーク炉製鋼の副生物である還元スラグに、鋼材の加工工程で発生するスケールと、炭素源となる材料とを混合し、混合物をアーク炉で溶融することにより、粉化の度合いが軽減された合成スラグを得ることからなる。
【０００７】
【発明の実施形態】
実際の操業に当たっては、装入材料が電導性の低い物質だけではアーク加熱が困難であるから、溶融の初期に、適量のスクラップを装入して通電し、アークの形成と温度の上昇を助けるとよい。すなわち、アーク炉による溶融を行なうに当たり、還元スラグ、スケールおよびその他の原料の装入に先だって、または装入とともに、適量のスクラップを装入して通電し、スクラップを溶融させて種湯を形成し、アーク加熱を安定的に行える条件を用意した上で装入原料を溶融して合成スラグを形成し、合成スラグが形成されたならば、種湯を炉底に残して溶融した合成スラグを出湯し、冷却して合成スラグを取得するとともに、再び原料の装入を行なって操業を続ける、という手法である。種湯とその後の原料装入量との割合は、重量比にして、種湯：追装原料＝１：０．０３〜２．０の範囲、好適には１：０．０５〜１．０の範囲から選ぶ。
【０００８】
還元スラグとスケールとの配合比率は、溶融製品がほぼ酸化スラグの組成をもつように、それぞれの成分組成に応じて決定すればよい。酸化スラグ、還元スラグおよびスケールの分析例を示せば、つぎのとおりである（重量％）。
還元スラグとスケールとから、酸化スラグに近い組成をもつ合成スラグを得るためには、上記の分析例からも算出可能なように、両者の割合を、重量比にして、還元スラグ：スケール＝１：０．８〜１：１．３の範囲から選択すればよい。ＦｅＯの含有量が３０〜５０％の範囲にある合成スラグを製造すれば、粉化の少ない、路盤材として好適な製品が得られる。
【００１０】
炭素源は、溶融金属がさらに酸化されてＦｅＯを形成することを防止し、製品合成スラグ中のＦｅＯの割合が過大になることを避ける目的で添加する。具体的な炭素源材料としては、コークス、石炭、レトルトカーボンなど常用のものが使用できるが、コークスが取り扱いやすくて好ましい。スケールに対する炭素源材料の配合比率は、なるべく粉化しにくい合成スラグを得られるように選択する。適切な値は、スケール中のＦｅＯ含有量などによって異なるが、通常は重量比にして、スケール：炭素源材料（Ｃとして）＝１：０．０５〜１：０．２の範囲から選択すればよい。
【００１１】
アーク炉における原料混合物を溶融させるには、１５８０〜１６５０℃程度に加熱する必要があり、このような高温では炉の耐火物が損傷を受けやすいから、損傷をなるべく少なくする配慮が必要である。この目的は、装入原料にＭｇＯ成分を含有するレンガ屑を添加して操業することによって、ある程度達成できる。ＭｇＯ耐火物には、しばしばＣを添加したＭｇＯ−Ｃ系のものがあり、その粉末などを使用すれば、Ｃ成分を上記の炭素源材料として利用することもでき、一挙両得である。
【００１２】
【実施例】
容量２０Ｔのアーク炉に、つぎの初装原料を装入し、通電して装入原料を溶融した。
スクラップ（新断） １４Ｔ
還元スラグ ２Ｔ
スケール ２Ｔ
ＭｇＯ−Ｃレンガ屑 １００ｋｇ
炭材（コークス） １２０ｋｇ
【００１３】
通電開始から１．５時間後、溶融したスラグの一部をスラグパンに排出し、つぎの定常装入原料を装入して溶融作業を継続した。
還元スラグ ２００ｋｇ
スケール ２００ｋｇ
炭材（コークス） ４０ｋｇ
【００１４】
通電開始から３．３時間後、再度溶融スラグを排出した。アーク炉内の温度は、１６３０℃に達していた。このようにして得られた合成スラグの成分は、下記のとおりである（重量％）。
これを路盤材として使用できるようにするためのエージングに要したスチームは、通常の酸化スラグのエージングに要したスチームの量と同等であった。
【００１６】
【発明の効果】
本発明にしたがって、製鋼プロセスから副生する還元スラグと、鋼材加工工程で発生するスケールとをアーク炉で溶融すれば、酸化スラグと同等のＦｅＯ含有量を有する合成スラグが得られる。この合成スラグは、粉化の度合いが還元スラグより著しく改善されていて、酸化スラグのそれと同等であって、路盤材として使用する場合に必要なスチームの量と所要時間を、還元スラグの数分の一に低減することができる。このようにして本発明は、還元スラグの用途を拡大し、あわせて高炉製銑への利用が困難な条件下における、スケールの処理を容易にする。すなわち本発明により、資源の有効利用と環境問題の解決とが同時に実現するという利益が得られる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a roadbed material using reduced slag, which is a by-product of arc furnace steelmaking, and also proposes a method for treating scale generated in a steel processing step.
[0002]
[Prior art]
As is well known, slag, which is a by-product of arc furnace steelmaking, includes oxidized slag generated during the oxidation refining phase and reduced slag generated during the reduction refining phase, both of which are used as roadbed materials. . However, since these slags contain a large amount of CaO, they pulverize when they absorb water and become Ca (OH) 2 . Therefore, in order to prevent harmful effects caused by pulverization, the slag cannot be used unless it is subjected to a process called “aging” in which the slag is placed under conditions of high humidity and temperature. The degree of pulverization is not so much for oxidized slag, but the reduced slag is remarkable, and a large amount of steam corresponding to 3 to 4 times the oxidized slag is consumed to perform aging.
[0003]
On the other hand, when hot working such as rolling or forging of steel is performed, a “scale” is generated in which the surface of a high-temperature material is oxidized and peeled off. Since the component is almost FeO, if there is equipment for blast furnace ironmaking, it can be reused there as a raw material for iron making, and it is often the case that it is treated as such. However, when there is no blast furnace nearby, it is difficult to use, and transporting to an ironworks will of course affect the cost of ironmaking, which is disadvantageous as a treatment method. If it is to be disposed of, the environmental impact must be taken into account, which ultimately costs money.
[0004]
The inventors pay attention to the fact that the oxidized slag contains a large amount of FeO and is common with the scale. By integrating the reduced slag with the scale, the inventors have a component composition close to that of oxidized slag. When the reduced slag and scale were melted together in an arc furnace, the synthesized slag as expected was obtained, and it was confirmed that this was useful as a road material.
[0005]
[Problems to be solved by the invention]
The object of the present invention is to provide a method for producing a synthetic slag with a light aging burden from reduced slag, using the findings of the inventors, and using it as a roadbed material, and also disposing of the scale. It is to provide a suitable way.
[0006]
[Means for Solving the Problems]
In the method for producing a roadbed material according to the present invention that achieves the above object, the reduced slag, which is a by-product of arc furnace steelmaking, is mixed with a scale generated in a steel material processing step and a material that is a carbon source, and the mixture is mixed. By melting in an arc furnace, synthetic slag having a reduced degree of powdering is obtained.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In actual operation, since it is difficult to heat the arc only with a material with low conductivity, the appropriate amount of scrap is charged and energized at the initial stage of melting, helping to form an arc and increase the temperature. Good. In other words, when melting in an arc furnace, an appropriate amount of scrap is charged and energized prior to or together with charging of reducing slag, scale and other raw materials, and the scrap is melted to form seed water. After preparing the conditions for stable arc heating, the raw materials are melted to form a synthetic slag. Once the synthetic slag is formed, the molten synthetic slag is left at the bottom of the furnace and the molten synthetic slag is discharged. In this method, the synthetic slag is obtained by cooling, and the raw material is charged again to continue the operation. The ratio of the seed hot water and the amount of the raw material charged thereafter is, as a weight ratio, in the range of seed hot water: additional raw material = 1: 0.03-2.0, preferably 1: 0.05-1.0. Choose from a range of
[0008]
What is necessary is just to determine the compounding ratio of reduced slag and a scale according to each component composition so that a molten product may have a composition of oxidation slag. An analysis example of oxidized slag, reduced slag, and scale is as follows (% by weight).
In order to obtain a synthetic slag having a composition close to oxidized slag from the reduced slag and scale, the ratio of the two is in a weight ratio so that it can be calculated from the above analysis example, and reduced slag: scale = 1. : Select from the range of 0.8 to 1: 1.3. If a synthetic slag having a FeO content in the range of 30 to 50% is produced, a product suitable as a roadbed material with less powdering can be obtained.
[0010]
The carbon source is added for the purpose of preventing the molten metal from being further oxidized to form FeO and avoiding an excessive proportion of FeO in the product synthesis slag. As specific carbon source materials, conventional materials such as coke, coal, and retort carbon can be used, but coke is preferable because it is easy to handle. The blending ratio of the carbon source material to the scale is selected so as to obtain a synthetic slag that is as difficult as possible to powder. The appropriate value varies depending on the FeO content in the scale and the like, but is usually selected from the range of scale: carbon source material (as C) = 1: 0.05 to 1: 0.2 by weight ratio. Good.
[0011]
In order to melt the raw material mixture in the arc furnace, it is necessary to heat to about 1580 to 1650 ° C. Since the refractory of the furnace is easily damaged at such a high temperature, it is necessary to consider to minimize the damage. This purpose can be achieved to some extent by operating by adding brick waste containing MgO component to the charging raw material. MgO refractories are often MgO-C-based with C added, and if the powder is used, the C component can be used as the above carbon source material.
[0012]
【Example】
The following initial raw material was charged into an arc furnace having a capacity of 20 T, and the charged raw material was melted by energization.
Scrap (new) 14T
Reduced slag 2T
Scale 2T
MgO-C brick scrap 100kg
Charcoal (coke) 120kg
[0013]
1.5 hours after the start of energization, a part of the molten slag was discharged into a slag pan, and the next steady charging material was charged to continue the melting operation.
Reduced slag 200kg
Scale 200kg
Charcoal (coke) 40kg
[0014]
After 3.3 hours from the start of energization, the molten slag was discharged again. The temperature in the arc furnace reached 1630 ° C. The components of the synthetic slag thus obtained are as follows (% by weight).
The steam required for aging so that it can be used as a roadbed material was equivalent to the amount of steam required for aging of normal oxidation slag.
[0016]
【The invention's effect】
According to the present invention, if the reduced slag by-produced from the steelmaking process and the scale generated in the steel material processing step are melted in an arc furnace, a synthetic slag having an FeO content equivalent to that of oxidized slag can be obtained. This synthetic slag has a significantly improved degree of pulverization compared to reduced slag, and is equivalent to that of oxidized slag, and the amount of steam and time required for use as roadbed material can be reduced by several minutes. It can be reduced to one. In this way, the present invention expands the application of reduced slag and facilitates the treatment of scales under conditions that are difficult to use for blast furnace ironmaking. That is, according to the present invention, there is a benefit that effective use of resources and solution of environmental problems can be realized simultaneously.
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003130480A JP4360117B2 (en) | 2003-05-08 | 2003-05-08 | Method for manufacturing roadbed material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003130480A JP4360117B2 (en) | 2003-05-08 | 2003-05-08 | Method for manufacturing roadbed material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2004331461A JP2004331461A (en) | 2004-11-25 |
| JP4360117B2 true JP4360117B2 (en) | 2009-11-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003130480A Expired - Fee Related JP4360117B2 (en) | 2003-05-08 | 2003-05-08 | Method for manufacturing roadbed material |
Country Status (1)
| Country | Link |
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| JP (1) | JP4360117B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4734167B2 (en) * | 2006-05-08 | 2011-07-27 | 新日本製鐵株式会社 | Steelmaking slag treatment method |
| JP2013071875A (en) * | 2011-09-28 | 2013-04-22 | Hoshino Sansho:Kk | Method for modifying electric arc furnace reducing slag |
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2003
- 2003-05-08 JP JP2003130480A patent/JP4360117B2/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| JP2004331461A (en) | 2004-11-25 |
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