JP3845160B2 - Slag coating method - Google Patents
Slag coating method Download PDFInfo
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- JP3845160B2 JP3845160B2 JP35394796A JP35394796A JP3845160B2 JP 3845160 B2 JP3845160 B2 JP 3845160B2 JP 35394796 A JP35394796 A JP 35394796A JP 35394796 A JP35394796 A JP 35394796A JP 3845160 B2 JP3845160 B2 JP 3845160B2
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- Prior art keywords
- slag
- converter
- refractory
- iron oxide
- coating method
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Description
【０００１】
【発明の属する技術分野】
本発明は、溶融金属反応容器、特に転炉の内張り耐火物の損耗を抑制するためのスラグコーティング方法に関するものである。
【０００２】
【従来の技術】
転炉の内張り耐火物の損耗を抑制するための技術として、特開昭５３−３７１２０号公報、特公昭５９−３８２８２号公報で提案のスラグコーティング方法がある。これは、出鋼後転炉炉内に残留させたスラグに軽焼ドロマイト、生ドロマイトまたは石灰石等のスラグ耐火度向上材を投入し、スラグの耐火度を増加させた上で、転炉炉体の傾動やあるいは底吹羽口からのガス吹き込みでスラグを内張り耐火物に付着させる方法である。すなわち、内張り耐火物表面にコーティング層を形成させることで、吹錬中のスラグとの直接的な接触防止による溶損の抑制や、発生熱応力の低減での熱応力破壊による剥離損耗の抑制を図るというものである。
【０００３】
【発明が解決しようとする課題】
しかしながら、出鋼後炉内に残留するスラグに耐火度向上材を投入するとスラグの粘性が向上して、流動性、飛散性が悪くなり転炉炉体の傾動やあるいは底吹羽口からのガス吹き込みを行うだけでは、充分なスラグコーティング性が得られないという現象が発生する場合があった。
【０００４】
本発明は、スラグ耐火度向上材を投入しても充分なラグの流動性、飛散性を確保して、コーティング性の良好なスラグを得ることを課題とするものである。
【０００５】
【課題を解決するための手段】
本発明者らは、上記スラグに耐火度向上材を投入するとスラグの粘性が向上して、流動性、飛散性が悪くなる現象の原因究明を行う過程で、スラグ中のＦｅＯ、Ｆｅ2Ｏ3である鉄酸化物濃度が重要な役割を果たすのではないかと推定した。
すなわち、スラグ中の鉄酸化物濃度が増大すると、スラグの融点が低下し、スラグの粘度が著しく低下するために、スラグコーティング性が低下するのではないかと推察して試験検討を行った結果、図１に示す知見を得た。
【０００６】
図１は、吹錬終了時のスラグ中の鉄酸化物濃度とスラグコーティング性との関係を示すものであり、これからスラグ中の鉄酸化物濃度が１５％以下になるとスラグコーティング性が優れることが判明した。
なお、スラグコーティング性は、出鋼側、裝入側、トラニオンの両側の４方向に対して、次に示す様な目視判断による点数化表示を行った。
付着スラグにより煉瓦目地が全て覆われている ：３点
付着スラグにより煉瓦目地が半分覆われている ：２点
付着スラグにより煉瓦目地が全く覆われていない：１点
スラグコーティング性は、点数が高いほど優れていることを示す。
【０００７】
本発明は上記知見によりなされたものであり、その手段１は、出鋼後に転炉炉内に溶鋼１ｔ当たり３０ｋｇ以上残留させたスラグに耐火度向上材を投入し、該スラグを転炉内張り耐火物に付着させ内張り耐火物の損耗を抑制するスラグコーティング方法において、前記耐火度向上材を投入する前のスラグ中のＦｅＯ、Ｆｅ2Ｏ3等の鉄酸化物濃度を測定し、該鉄酸化物濃度が１５％超である場合には、スラグ酸化度低減材を投入してスラグ中の鉄酸化物濃度を１５％以下にして該スラグの粘性を低減せしめた後、前記耐火度向上材として、生ドロマイト、石灰石、転炉滓のうち１種または２種以上を投入してスラグの耐火度を向上させて転炉内張り耐火物に付着させるスラグコーティング方法である。
【０００８】
さらに、手段２は、上記手段１のスラグ酸化度低減材としてはスラグ中の鉄酸化物の還元剤として作用させるものであり、コークス、アルミニウム含有化合物、マグネシウム含有化合物のうち１種または２種以上の混合物である。
【０００９】
また、本発明が適用できる転炉としては、ＭｇＯ−Ｃ質、ＭｇＯ−ＣａＯ−Ｃ質、ＭｇＯ−Ｃｒ2Ｏ3 質のいずれの内張り耐火物を使用しているものも可能である。
【００１０】
さらに、前記アルミニウム含有化合物としては、アルミニウム単体物の他に該アルミニウムを５０％程度以上含有するものであれば好ましく、アルミニウムを精製または鋳造する際に生成するアルミニウムドロスのいずれでも使用可能である。また、マグネシウム含有化合物としては、前記アルミニウムと同様にマグネシウム単体物の他にマグネシウムを５０％程度以上含有するものであれば好ましく、マグネシウムを精製または鋳造する際に生成するマグネシウムドロスのいずれでも使用可能である。
【００１１】
本発明のスラグ酸化度低減材は、スラグ中のＦｅＯ、Ｆｅ2Ｏ3等の鉄酸化物と次式に示す様な反応を起こし、鉄酸化物を鉄に還元させる。
FetO ＋ (C,Al,Mg) → t Fe ＋ (CO,Al2O3,MgO)
その結果、スラグ中の鉄酸化物濃度を１５％以下に低下することで、スラグの融点が上昇してスラグの粘性が増大し、前記スラグ耐火度向上材を投入しても極端にスラグの流動性が悪化することがないために、スラグコーティング性の低下を防止することができる。
【００１２】
なお、内張り耐火物全体にわたり、均一にスラグコーティングを行うためには、吹錬終了後に生成するスラグ量は溶鋼１ｔ当たり３０ｋｇ以上とすることが望ましい。ただし、吹錬終了後に生成するスラグ量が溶鋼１ｔ当たり５０ｋｇ以上となる場合には、スラグ酸化度低減材とスラグ中のＴ．Ｆｅとの還元反応効率を高めるために、スラグ酸化度低減材を残留スラグに投入する前に、その生成量の約１／３程度のスラグを排出した方が望ましい。
【００１３】
ここで、溶鋼１ｔ当たりの生成スラグ量は、以下に定義されるものである。
生成スラグ量(kg/t)＝（生石灰投入量×生石灰中のＣａＯ含有率＋石灰石投入量×石灰石中のＣａＯ含有率＋軽焼ドロマイト投入量×軽焼ドロマイト中のＣａＯ含有率＋生ドロマイト投入量×生ドロマイト中のＣａＯ含有率）／（溶鋼量×スラグ中のＣａＯ濃度）。
【００１４】
【発明の実施の形態】
以下に本発明の実施の形態を示す。
ＭｇＯ：８０ｗｔ％、Ｃ：２０ｗｔ％のＭｇＯ−Ｃ質耐火物で内張りした、容量：３４０ｔの上底吹き転炉で溶銑を吹錬して所定成分の溶鋼とし、この溶鋼を出鋼口から出鋼する。
出鋼後、転炉内に残留したスラグをサンプリングし、このサンプリングスラグを蛍光Ｘ線分析してスラグ中の鉄酸化物濃度を測定する。
そして、この鉄酸化物濃度が１５％超であればスラグ酸化度低減材を炉内に投入した後、転炉を複数回傾動して、炉内残留スラグ中の鉄酸化物を酸化度低減材で還元反応させて、該スラグ中の鉄酸化物濃度を１５％以下にして、スラグの融点を上昇して粘性を良好にする。
この粘性が良好になったスラグ中に耐火度向上材を投入して、再度、転炉を複数回傾動する事により該転炉の内張り耐火物をスラグでコーティングする。
なお、出鋼後のスラグ、つまり、耐火度向上材投入前のスラグ中の鉄酸化物濃度が１５％以下の場合は、スラグ酸化度低減材の投入は不要であることは当然である。
【００１５】
【実施例】
以下表１に従って本発明の実施例を比較例、従来例と供に説明する。
本実施例１〜７は、吹錬終了時のスラグ中の鉄酸化物濃度が１５％超であるにもかかわらず、優れたスラグコーティング性を示した。
【００１６】
一方、比較例１はスラグ酸化度低減材の投入量が少なく、スラグ中の鉄酸化物濃度が１５％以下にならなく、スラグコーティング性に劣っていた。
【００１７】
また、従来例１はスラグ中の鉄酸化物濃度が１５％超であるにもかかわらず、スラグ酸化度低減材を投入しなかったので、非常にスラグコーティング性に劣った。
【００１８】
【表１】
図２に、転炉稼働当初から４０００回使用した時点までの本発明例を適用した場合と、上記従来例とにおけるトラニオン部の内張り耐火物の損耗量の推移の比較を示す。
この図から分かるように本発明例の適用により、従来例に比べ４０００回使用時点で、内張り耐火物の損耗量において２００ｍｍの低減効果が確認された。
【００２０】
【発明の効果】
本発明により、従来十分なスラグコーティング性が得られなかった性状のスラグに対してもスラグコーティング性を向上させることができ、その結果転炉内張り耐火物の損耗量低減での転炉炉体寿命の延長や、補修材使用量削減による耐火物コストの削減が可能となる等の効果を奏するものである。
【図面の簡単な説明】
【図１】スラグ中の鉄酸化物濃度とスラグコーティング性との関係を示した図。
【図２】本発明例と従来例におけるトラニオン部の転炉内張り耐火物の損耗量の推移を示した図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a slag coating method for suppressing wear of a molten metal reaction vessel, particularly a refractory lining the converter.
[0002]
[Prior art]
As a technique for suppressing the wear of the refractory lining the converter, there is a slag coating method proposed in JP-A-53-37120 and JP-B-59-38282. This is because the slag remaining in the converter furnace after steel is put into a slag fire resistance improver such as light-burned dolomite, raw dolomite or limestone, and the slag fire resistance is increased. This is a method of attaching slag to the lining refractory by tilting of the gas or by blowing gas from the bottom blowing tuyere. In other words, by forming a coating layer on the lining refractory surface, it is possible to suppress melting damage by preventing direct contact with the slag during blowing, and to suppress peeling wear due to thermal stress failure by reducing the generated thermal stress. It is intended.
[0003]
[Problems to be solved by the invention]
However, if a refractory improver is added to the slag remaining in the furnace after steel output, the viscosity of the slag will improve, and the fluidity and scattering will deteriorate, resulting in tilting of the converter furnace body or gas from the bottom tuyeres. There has been a case where a phenomenon that sufficient slag coating properties cannot be obtained only by blowing.
[0004]
The present invention, fluidity of sufficient lugs be charged slag refractoriness improver, to ensure fluffy, it is an object that you obtain coatings having good slag.
[0005]
[Means for Solving the Problems]
In the process of investigating the cause of the phenomenon in which the viscosity of the slag is improved and the fluidity and scattering properties are deteriorated when the fire resistance improving material is added to the slag, the present inventors have investigated FeO and Fe 2 O 3 in the slag. It was estimated that the iron oxide concentration might play an important role.
When ie, iron oxide concentration in the slag increases, the melting point of the slag is decreased, because the viscosity of the slag is significantly lowered, the slag coating properties were tested examined speculated that it would be reduced As a result, the knowledge shown in FIG. 1 was obtained.
[0006]
FIG. 1 shows the relationship between the iron oxide concentration in the slag at the end of blowing and the slag coating properties. From now on, when the iron oxide concentration in the slag becomes 15% or less, the slag coating properties may be excellent. found.
In addition, the slag coating property was scored by visual judgment as shown below for the four directions of the steel output side, the insertion side, and the both sides of the trunnion.
Adhesive slag covers all brick joints: 3 point adhering slag covers half brick joints: 2 adhering slag does not cover brick joints at all: 1 point slag coating performance is high It shows that it is excellent.
[0007]
The present invention has been made by the above findings, the
[0008]
Further, the
[0009]
In addition, as the converter to which the present invention can be applied, one using any lining refractory material of MgO-C quality, MgO-CaO-C quality, and MgO-Cr 2 O 3 quality is also possible.
[0010]
Further, the aluminum-containing compound is preferably one containing about 50% or more of the aluminum in addition to the aluminum simple substance, and any aluminum dross produced when aluminum is refined or cast can be used. Further, as the magnesium-containing compound, it is preferable that the magnesium-containing compound contains about 50% or more of magnesium in addition to the magnesium simple substance, and any magnesium dross produced when refining or casting magnesium can be used. It is.
[0011]
The slag oxidation degree reducing material of the present invention causes a reaction as shown in the following formula with iron oxides such as FeO 2 and Fe 2 O 3 in slag to reduce the iron oxide to iron.
Fe t O + (C, Al, Mg) → t Fe + (CO, Al 2 O 3 , MgO)
As a result, by reducing the iron oxide concentration in the slag to 15% or less, the melting point of the slag is increased and the viscosity of the slag is increased. Therefore, the deterioration of the slag coating property can be prevented.
[0012]
In addition, in order to perform slag coating uniformly over the entire lining refractory, it is desirable that the amount of slag generated after the end of blowing is 30 kg or more per 1 ton of molten steel. However, when the amount of slag generated after the end of blowing is 50 kg or more per 1 ton of molten steel, the slag oxidation degree reducing material and T.sub. In order to increase the efficiency of the reduction reaction with Fe, it is desirable to discharge about 1/3 of the generated amount of slag before introducing the slag oxidation degree reducing material into the residual slag.
[0013]
Here, the amount of generated slag per 1 t of molten steel is defined as follows.
Amount of generated slag (kg / t) = (input amount of quick lime × CaO content in quick lime + input amount of limestone × CaO content in limestone + input amount of light-burned dolomite × content ratio of CaO in light-burned dolomite + input of raw dolomite Amount × CaO content in raw dolomite) / (molten steel amount × CaO concentration in slag).
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
MgO: 80 wt%, C: 20 wt% lined with MgO-C refractory, molten steel is blown into a molten steel of the specified component by blowing the hot metal in a capacity: 340t top-bottom blowing converter, and this molten steel is discharged from the steel outlet. Steel.
After the steel is extracted, the slag remaining in the converter is sampled, and this sampling slag is subjected to fluorescent X-ray analysis to measure the iron oxide concentration in the slag.
And if this iron oxide concentration exceeds 15%, after putting the slag oxidation degree reducing material into the furnace, the converter is tilted several times, and the iron oxide in the residual slag in the furnace is reduced to the oxidation degree reducing material. To reduce the iron oxide concentration in the slag to 15% or less, thereby increasing the melting point of the slag and improving the viscosity.
The viscosity was charged refractoriness improver in the slag became better, again Cote I ring at the slag refractory lining of said transfer furnace by a plurality of times tilted converter.
In addition, when the iron oxide density | concentration in the slag after steel output, ie, the slag before refractory improvement material injection | throwing-in, is 15% or less, it is natural that injection | throwing-in of a slag oxidation degree reduction material is unnecessary.
[0015]
【Example】
Hereinafter, examples of the present invention will be described together with comparative examples and conventional examples according to Table 1.
This embodiment 1-7, the iron oxide concentration in the slag during blowing end spite is 15 percent, showed excellent slug coating property.
[0016]
On the other hand, in Comparative Example 1, the amount of the slag oxidation degree reducing material was small, the iron oxide concentration in the slag did not become 15% or less, and the slag coating property was inferior.
[0017]
Moreover, although the prior art example 1 did not introduce | transduce a slag oxidation degree reducing material, although the iron oxide density | concentration in slag was over 15%, it was very inferior to slag coating property.
[0018]
[Table 1]
FIG. 2 shows a comparison of changes in the wear amount of the lining refractory in the trunnion portion between the case where the present invention example is applied from the beginning of the converter operation up to the point of
As can be seen from this figure, by applying the example of the present invention, a reduction effect of 200 mm in the amount of wear of the lining refractory was confirmed at the point of
[0020]
【The invention's effect】
According to the present invention, it is possible to improve the slag coating properties even for slags that have not been able to obtain sufficient slag coating properties in the past, and as a result, the life of the converter furnace body by reducing the amount of wear of the refractory lining the converter As a result, the refractory cost can be reduced by extending the amount of use and reducing the amount of repair material used.
[Brief description of the drawings]
FIG. 1 is a diagram showing the relationship between iron oxide concentration in slag and slag coating properties.
FIG. 2 is a graph showing a change in the amount of wear of a converter lining refractory in a trunnion portion in the present invention example and a conventional example.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35394796A JP3845160B2 (en) | 1996-12-19 | 1996-12-19 | Slag coating method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35394796A JP3845160B2 (en) | 1996-12-19 | 1996-12-19 | Slag coating method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10183219A JPH10183219A (en) | 1998-07-14 |
| JP3845160B2 true JP3845160B2 (en) | 2006-11-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35394796A Expired - Fee Related JP3845160B2 (en) | 1996-12-19 | 1996-12-19 | Slag coating method |
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| Country | Link |
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| JP (1) | JP3845160B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6627256B1 (en) * | 1998-10-05 | 2003-09-30 | Kawasaki Steel Corporation | Method for slag coating of converter wall |
| EP1281776B1 (en) * | 2001-08-03 | 2004-06-30 | Minerals & Metals Italia S.p.A. | Composition for hindering the formation of iron oxides in steel-melting slag and process for obtaining a slag with a low level of iron oxides |
| KR100544466B1 (en) * | 2001-09-07 | 2006-01-24 | 주식회사 포스코 | Method for coating inside wall of convert with slag |
| KR100923793B1 (en) * | 2002-12-17 | 2009-10-27 | 주식회사 포스코 | Slag coating method |
| CN106191370B (en) * | 2016-08-12 | 2017-12-26 | 唐山市德龙钢铁有限公司 | A kind of maintaining method of converter lining |
-
1996
- 1996-12-19 JP JP35394796A patent/JP3845160B2/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| JPH10183219A (en) | 1998-07-14 |
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