JP2020180311A - Method for preventing slag outflow in converter - Google Patents
Method for preventing slag outflow in converter Download PDFInfo
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- JP2020180311A JP2020180311A JP2019081661A JP2019081661A JP2020180311A JP 2020180311 A JP2020180311 A JP 2020180311A JP 2019081661 A JP2019081661 A JP 2019081661A JP 2019081661 A JP2019081661 A JP 2019081661A JP 2020180311 A JP2020180311 A JP 2020180311A
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- 239000002893 slag Substances 0.000 title claims abstract description 145
- 238000000034 method Methods 0.000 title claims abstract description 18
- 239000000835 fiber Substances 0.000 claims abstract description 59
- 238000002844 melting Methods 0.000 claims abstract description 12
- 230000008018 melting Effects 0.000 claims abstract description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 46
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 32
- 229910052742 iron Inorganic materials 0.000 claims description 16
- 229910000831 Steel Inorganic materials 0.000 abstract description 19
- 239000010959 steel Substances 0.000 abstract description 19
- 238000007599 discharging Methods 0.000 abstract 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 12
- 239000002245 particle Substances 0.000 description 8
- 238000007670 refining Methods 0.000 description 8
- 235000012255 calcium oxide Nutrition 0.000 description 6
- 239000000292 calcium oxide Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 230000001590 oxidative effect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-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
- 230000005484 gravity Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 229910000514 dolomite Inorganic materials 0.000 description 1
- 239000010459 dolomite Substances 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000012768 molten material Substances 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
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
Landscapes
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
Description
本発明は、転炉内スラグの流出防止方法に関するものである。 The present invention relates to a method for preventing the outflow of slag in a converter.
転炉精錬においては、溶銑、あるいは予備処理を行った溶鉄を転炉内に装入し、上吹きランスあるいは底吹きを併用して酸素ガスを供給して酸化精錬を行い、脱炭、脱りんあるいはその両方の精錬を行う。精錬完了後において、転炉内には精錬を終わった溶鉄（溶鋼）とともに、溶融スラグが形成され、溶融スラグは溶鉄の上部に浮上している。精錬は酸化精錬であり、溶融スラグは酸化性の高い（酸化鉄を多く含有する）スラグである。また脱りん精錬を行う場合は、脱りん精錬の結果として溶融スラグ中のりん含有量が高くなっている。 In converter refining, hot metal or pretreated molten iron is charged into the converter, and oxygen gas is supplied in combination with top-blown lance or bottom-blown to perform oxidative refining, decarburization and dephosphorization. Or both are refined. After the completion of refining, molten slag is formed in the converter together with the molten iron (molten steel) that has been refined, and the molten slag floats above the molten iron. Refining is oxidative refining, and molten slag is highly oxidative (rich in iron oxide) slag. When dephosphorization refining is performed, the phosphorus content in the molten slag is high as a result of the dephosphorization refining.
転炉の側面には出湯孔が設けられている。主に精錬が完了した溶鋼を払い出すためのものである。通常は出鋼孔と呼ばれる。精錬完了後、転炉を傾動することにより、出湯孔を経由して溶鉄を下方の取鍋へと払い出す（以下「出湯」という。）。通常は出鋼と呼ばれる。出湯の末期、転炉内の溶鉄が少なくなってくると、溶鉄層の上に形成された溶融スラグが溶鉄に巻き込まれ、溶鉄とともに取鍋内に排出される。上述のように、転炉内の溶融スラグは酸化性が高く、かつ有害不純物であるりんを高い濃度で含有している。従って、取鍋内に溶融スラグが大量に流出すると、スラグの酸化性が高いために鋼の清浄度が損なわれ、またスラグ中のりんが溶鉄に戻る、いわゆる復りん現象が起こるため、好ましくない。 A hot water outlet is provided on the side surface of the converter. It is mainly for paying out molten steel that has been refined. Usually called a steel hole. After the refining is completed, the converter is tilted to discharge the molten iron to the lower ladle via the hot water hole (hereinafter referred to as "hot water"). Usually called steel output. At the end of hot water discharge, when the amount of molten iron in the converter becomes low, the molten slag formed on the molten iron layer is caught in the molten iron and discharged into the ladle together with the molten iron. As described above, the molten slag in the converter is highly oxidizing and contains phosphorus, which is a harmful impurity, at a high concentration. Therefore, if a large amount of molten slag flows out into the ladle, the cleanliness of the steel is impaired due to the high oxidizing property of the slag, and the phosphorus in the slag returns to molten iron, which is not preferable. ..
転炉からの出湯時にスラグ流出を防止するための代表的な技術として、スラグカットボールが用いられている。スラグカットボールは、直径が出湯孔よりも大きく、スラグと溶鉄の中間比重を持ち、出湯時に溶鉄が出終わり溶融スラグが出始める時期に該スラグカットボールで出湯孔に栓をするものである（非特許文献１参照）。特許文献１に記載のように、この目的を達成するには、ボールの投入位置をほぼ出湯孔の直上とし、かつ出湯末期に投入することが必要とされている。 A slag cut ball is used as a typical technique for preventing slag outflow when hot water is discharged from a converter. The slag cut ball has a diameter larger than that of the hot water outlet, has an intermediate specific gravity between the slag and the molten iron, and plugs the hot water outlet with the slag cut ball at the time when the molten iron finishes out and the molten slag begins to come out at the time of hot water discharge. See Non-Patent Document 1). As described in Patent Document 1, in order to achieve this purpose, it is required that the ball is thrown in at a position substantially directly above the hot water outlet and at the end of the hot water discharge.
上記スラグカットボールを用いる場合、転炉内の溶湯表面でボールが浮遊する位置が一定でないため、出湯孔の閉止が不安定であるという問題があった。この問題を解決するため、スラグダーツが提案されている。スラグダーツは、特許文献２に記載のように、頭部とこれに連接される足部とを有する。出湯中、足部が溶鋼の流れを受けて、スラグダーツ全体が転炉の出湯口に引き寄せられ、出湯口の上方に待機した状態になる。こうして、安定して出湯口の閉止ができるようになった。 When the above-mentioned slag cut ball is used, there is a problem that the closing of the hot water hole is unstable because the position where the ball floats on the surface of the molten metal in the converter is not constant. Slug darts have been proposed to solve this problem. As described in Patent Document 2, the slug darts have a head and a foot portion connected to the head. During hot water, the foot part receives the flow of molten steel, and the entire slag darts are drawn to the hot water outlet of the converter, and the slag darts stand by above the hot water outlet. In this way, the outlet can be closed stably.
スラグダーツの使用に際しては、特許文献３に記載のように、アーム先端にスラグダーツを掴んでいる台車を直線状に延びるレール上で同一方向に走行させて転炉内に持ち込み、転炉からの出湯末期にスラグダーツを転炉の出湯孔内に挿入する。レールは転炉前部の天井部分に設けられている。 When using slag darts, as described in Patent Document 3, a carriage holding the slag darts at the tip of the arm is run in the same direction on a rail extending in a straight line and brought into the converter to bring it into the converter. Insert the slag darts into the hot water hole of the converter at the end of hot water. The rail is provided on the ceiling of the front part of the converter.
特許文献４には、転炉脱りんにおけるスラグ混流防止法として、出湯のため傾転した転炉の出湯孔上部に、１〜５ｋｇ／ｔｏｎの軽焼ドロマイトまたは生石灰を投入する方法が開示されている。出湯中の出湯孔ならびにその周囲の塩基度のみを局部的に上昇せしめてスラグを固化せしめる、としている。 Patent Document 4 discloses, as a method for preventing slag mixing in converter dephosphorization, a method of pouring 1 to 5 kg / ton of lightly baked dolomite or quicklime into the upper part of a hot water outlet of a converter tilted for hot water. There is. It is said that the slag is solidified by locally increasing only the basicity of the hot water outlet hole and its surroundings during hot water discharge.
特許文献５には、溶鋼上のスラグにプラスチックを添加してプラスチックをスラグの有する熱によって分解させ、プラスチック分解時の吸熱反応を利用してスラグを冷却し、スラグを固化させる或いはスラグの流出が妨げられるようにスラグの粘性を高める、スラグの流出防止方法が開示されている。プラスチックの添加量が少ないと、スラグに対する吸熱量が少ない上に、燃焼に必要な酸素源の供給の遅れも少なくなり、スラグの固化が阻害される。そのため、プラスチックの添加量は、溶鋼トン当たり１ｋｇ以上とすることが好ましいとしている。 In Patent Document 5, plastic is added to slag on molten steel to decompose the plastic by the heat of the slag, and the heat absorption reaction at the time of decomposition of the plastic is used to cool the slag to solidify the slag or cause the slag to flow out. Disclosed are methods of preventing slag outflow that increase the viscosity of the slag so that it is hindered. When the amount of plastic added is small, the amount of heat absorbed by the slag is small, and the delay in supplying the oxygen source required for combustion is also small, so that the solidification of the slag is hindered. Therefore, the amount of plastic added is preferably 1 kg or more per ton of molten steel.
スラグカットボール、スラグダーツを用いない場合、及び特許文献４、５のスラグ固化材を添加する場合において、出湯末期、出湯孔からの流出が溶鉄から溶融スラグに変化したのを目視で確認し、直ちに転炉を傾転して元の直立位置に戻すことにより、スラグの流出を停止している。 When slag cut balls and slag darts are not used, and when the slag solidifying material of Patent Documents 4 and 5 is added, it is visually confirmed that the outflow from the hot water outlet changes from molten iron to molten slag at the end of hot water discharge. Immediately, the converter is tilted back to its original upright position to stop the outflow of slag.
転炉からの出湯時にスラグ流出を防止する方法のうち、前記スラグダーツを用いようとすると、特許文献３に記載のように、転炉建屋の天井部分にレールを設け、スラグダーツを転炉内に誘導することが必要である。転炉、特に小型転炉においては、このようなスラグダーツ投入用の装置を転炉建屋に設置するスペースが存しない場合がある。一方、スラグカットボールを用いる場合、前述のように、転炉内の溶湯表面でボールが浮遊する位置が一定でないため、出湯孔の閉止が不安定であるという問題があった。 Among the methods for preventing slag outflow when hot water is discharged from the converter, if the slag darts are to be used, a rail is provided on the ceiling of the converter building and the slag darts are placed in the converter as described in Patent Document 3. It is necessary to induce to. In converters, especially small converters, there may be no space to install such a device for charging slag darts in the converter building. On the other hand, when a slag cut ball is used, as described above, there is a problem that the closing of the hot water outlet hole is unstable because the position where the ball floats on the surface of the molten metal in the converter is not constant.
溶鋼上のスラグにプラスチック等のスラグ固化材を添加してスラグを固化する前記方法では、１〜１０ｋｇ／ｔの多量の固化材を必要とし、また投入設備が大型となる課題があった。 The method of adding a slag solidifying material such as plastic to slag on molten steel to solidify the slag requires a large amount of solidifying material of 1 to 10 kg / t, and has a problem that the input facility becomes large.
本発明は、スラグダーツ投入装置を設置できないような転炉においても、転炉からの出湯時にスラグ流出を確実に防止できる、転炉内スラグの流出防止方法を提供することを目的とする。 An object of the present invention is to provide a method for preventing slag outflow in a converter, which can surely prevent slag outflow when hot water is discharged from the converter even in a converter in which a slag darts charging device cannot be installed.
即ち、本発明の要旨とするところは以下のとおりである。
［１］転炉の出湯孔から溶鉄を取り出す際に、転炉内スラグの流出を防止する方法であって、
出湯中に、融点が１５００℃以上である酸化物繊維を、転炉内の溶融スラグ表面に投入することを特徴とする転炉内スラグの流出防止方法。
［２］融点が１５００℃以上である前記酸化物繊維を、スラグカット栓とともに転炉内の溶融スラグ表面に投入することを特徴とする請求項１に記載の転炉内スラグの流出防止方法。
That is, the gist of the present invention is as follows.
[1] A method of preventing the outflow of slag in a converter when taking out molten iron from the hot water outlet of the converter.
A method for preventing outflow of slag in a converter, which comprises charging oxide fibers having a melting point of 1500 ° C. or higher onto the surface of molten slag in the converter during hot water discharge.
[2] The method for preventing outflow of slag in a converter according to claim 1, wherein the oxide fiber having a melting point of 1500 ° C. or higher is charged onto the surface of the molten slag in the converter together with a slag cut stopper.
本発明は、転炉の出湯孔から溶鉄を取り出す際に、融点が１５００℃以上である酸化物繊維を、転炉内の溶融スラグ表面に投入することにより、転炉内スラグの流出を防止することができる。 The present invention prevents the outflow of slag in a converter by putting oxide fibers having a melting point of 1500 ° C. or higher onto the surface of the molten slag in the converter when taking out molten iron from the hot water outlet of the converter. be able to.
本発明者は、転炉からの出湯時にスラグの流動性を低下させることによってスラグ流出を防止する方法として、繊維状の固化材を添加することに着目した。すなわち、一般的にスラグ中に固相粒子が懸濁すると見かけの粘度が増加（流動性低下）するが、固相粒子の形状が繊維状であれば、繊維同士が絡み合い、溶融スラグ中に添加した繊維がスラグと混合した後、繊維の間にスラグが拘束されることで、より少ない添加量でスラグの流動を抑制できるためである。ここで繊維とは、アスペクト比（長さ／直径）が１００以上の粒子と定義する。 The present inventor has focused on adding a fibrous solidifying material as a method of preventing slag outflow by reducing the fluidity of slag when hot water is discharged from a converter. That is, in general, when solid-phase particles are suspended in slag, the apparent viscosity increases (the fluidity decreases), but if the solid-phase particles are fibrous, the fibers are entangled with each other and added to the molten slag. This is because the slag is confined between the fibers after the resulting fibers are mixed with the slag, so that the flow of the slag can be suppressed with a smaller amount of addition. Here, the fiber is defined as a particle having an aspect ratio (length / diameter) of 100 or more.
繊維の材質としては、転炉出湯時のスラグからの伝熱によって溶融せず、かつスラグや溶鋼と反応しない必要があることから、１５００℃以上の融点を有する酸化物繊維とする必要がある。このような酸化物繊維の素材となる酸化物としては、アルミナ（Ａｌ2Ｏ3）（融点：２０７２℃）、ムライト（３Ａｌ2Ｏ3・２ＳｉＯ2−２Ａｌ2Ｏ3・ＳｉＯ2）（融点：１８５０℃）、ジルコニア（ＺｒＯ2）（融点：２７１５℃）、石英（ＳｉＯ2）（融点：１６５０℃）が好ましい。 As the material of the fiber, it is necessary to use an oxide fiber having a melting point of 1500 ° C. or higher because it is necessary that the fiber does not melt due to heat transfer from the slag when the hot water is discharged from the converter and does not react with the slag or molten steel. The oxide having a such an oxide fiber material, alumina (Al 2 O 3) (mp: 2072 ° C.), mullite (3Al 2 O 3 · 2SiO 2 -2Al 2 O 3 · SiO 2) ( mp: 1850 ° C.), zirconia (ZrO 2 ) (melting point: 2715 ° C.), quartz (SiO 2 ) (melting point: 1650 ° C.) are preferable.
繊維の長さと直径については限定されないが、繊維のアスペクト比が高い程、繊維同士が絡み合いやすくなるため、アスペクト比はできる限り高い方が好ましい。 The length and diameter of the fibers are not limited, but the higher the aspect ratio of the fibers, the easier it is for the fibers to be entangled with each other. Therefore, it is preferable that the aspect ratio is as high as possible.
上記の酸化物繊維は単体で投入しても効果を得られるが、出湯孔に栓をするスラグダーツやスラグカットボールとともに投入すれば、酸化物繊維が出湯孔近傍に到達しやすいため、より高い効果が得られる。以下、スラグカットボールやスラグダーツを含めて、出湯中に転炉内に投入し、溶湯に浮遊し、出湯末期にスラグ流出を防止する係止具を、総称して「スラグカット栓」と呼ぶ。 The above oxide fiber can be effective even if it is added alone, but it is higher if it is added together with slag darts or slag cut balls that plug the hot water hole because the oxide fiber easily reaches the vicinity of the hot water hole. The effect is obtained. Hereinafter, locking tools including slag cut balls and slag darts that are put into a converter during hot water discharge, float in the molten metal, and prevent slag outflow at the end of hot water discharge are collectively referred to as "slag cut plugs". ..
そこで実際に、１００ｔｏｎ転炉を用い、転炉からの出湯時に転炉内の溶融スラグ中に酸化物繊維を投入し、スラグカットの効果が得られるか、確認を行った。酸化物繊維として、直径が５μｍ〜３０μｍ、長さが３ｍｍ〜１００ｍｍのチョップドファイバー（短繊維）状のアルミナ酸化物繊維を用いた。 Therefore, we actually used a 100-ton converter and put oxide fibers into the molten slag in the converter when hot water was discharged from the converter, and confirmed whether the slag cutting effect could be obtained. As the oxide fiber, chopped fiber (short fiber) -like alumina oxide fiber having a diameter of 5 μm to 30 μm and a length of 3 mm to 100 mm was used.
転炉からの出湯時に、転炉内の出湯孔直上の位置に向けて、溶融スラグ表面に酸化物繊維を投入したところ、投入した酸化物繊維は溶融スラグ中に良好に混ざり合う状況が確認できた。投入した酸化物繊維と溶融スラグとの濡れ性が良好であり、短時間で酸化物繊維が溶融スラグ中に混合したものと推定できる。
出湯中の出湯流を目視で観察し、溶融スラグの流出が確認できた時点で転炉を傾転してスラグ流出を停止させた。
When the oxide fibers were added to the surface of the molten slag toward the position directly above the hot water outlet holes in the converter when the hot water was discharged from the converter, it was confirmed that the added oxide fibers were well mixed in the molten slag. It was. The wettability of the charged oxide fiber and the molten slag is good, and it can be estimated that the oxide fiber is mixed in the molten slag in a short time.
The flow of hot water during hot water was visually observed, and when the outflow of molten slag was confirmed, the converter was tilted to stop the outflow of slag.
酸化物繊維の添加量を０．０５〜０．５ｋｇ／ｔｏｎの範囲とし、取鍋に流出したスラグ量との関係を評価したところ、酸化物繊維を添加しない場合と比較し、取鍋流出スラグ量が低減し、酸化物繊維の添加量が多くなるほど取鍋流出スラグ量が減少することが明らかとなった。添加する酸化物繊維の繊維同士が絡み合い、溶融スラグ中に添加した酸化物繊維がスラグと混合した後、繊維の間にスラグが拘束されることで、より少ない添加量でスラグの流動を抑制できたものと考えられる。 When the amount of oxide fiber added was in the range of 0.05 to 0.5 kg / ton and the relationship with the amount of slag that flowed out to the ladle was evaluated, the slag that flowed out of the ladle was compared with the case where no oxide fiber was added. It was clarified that the amount of ladle outflow slag decreased as the amount decreased and the amount of oxide fiber added increased. After the oxide fibers added are entangled with each other and the oxide fibers added in the molten slag are mixed with the slag, the slag is constrained between the fibers, so that the flow of the slag can be suppressed with a smaller amount of addition. It is thought that it was.
また、同じ転炉を用い、転炉からの出湯時に転炉内の溶融スラグ中にスラグカットボールを投入するとともに酸化物繊維を投入し、酸化物繊維投入による効果が得られるか、確認を行った。酸化物繊維の種類と添加量は上記と同様とした。出湯孔から流出する溶融物が溶鋼から溶融スラグに変化するタイミングで、スラグカットボールが出湯孔を閉塞することで、取鍋に流出する溶融スラグの量を低減することができる。酸化物繊維の投入量と取鍋に流出したスラグ量との関係を評価したところ、酸化物繊維を添加しない場合と比較し、取鍋流出スラグ量が低減し、酸化物繊維の添加量が多くなるほど取鍋流出スラグ量が減少することが明らかとなった。即ち、スラグカットボールの投入と酸化物繊維の投入を併用する場合においても、酸化物繊維を添加する効果が確認できた。 Also, using the same converter, when hot water is discharged from the converter, slag cut balls are put into the molten slag in the converter and oxide fibers are put in, and it is confirmed whether the effect of putting the oxide fibers can be obtained. It was. The type and amount of oxide fiber added were the same as above. The amount of molten slag flowing out to the ladle can be reduced by closing the hot water hole with the slag cut ball at the timing when the molten material flowing out from the hot water hole changes from molten steel to molten slag. When the relationship between the amount of oxide fiber input and the amount of slag flowing out to the ladle was evaluated, the amount of slag flowing out of the ladle was reduced and the amount of oxide fiber added was large compared to the case where no oxide fiber was added. Indeed, it became clear that the amount of ladle outflow slag decreased. That is, the effect of adding the oxide fiber was confirmed even when the slag cut ball was added and the oxide fiber was added at the same time.
以上のとおり、融点が１５００℃以上である酸化物繊維を、スラグカットボールとともに転炉内の溶融スラグ表面に投入することにより、溶融スラグ流出を有効に低減することができる。スラグダーツが利用できる転炉であれば、融点が１５００℃以上である酸化物繊維を、スラグダーツとともに転炉内の溶融スラグ表面に投入することとしてもよい。 As described above, by putting the oxide fiber having a melting point of 1500 ° C. or higher on the surface of the molten slag in the converter together with the slag cut ball, the outflow of molten slag can be effectively reduced. If the converter can use slag darts, oxide fibers having a melting point of 1500 ° C. or higher may be charged to the surface of the molten slag in the converter together with the slag darts.
使用回数が１５００回以上である転炉で、溶銑１００ｔｏｎを脱炭吹錬した。吹錬終了後の溶融スラグは、塩基度（ＣａＯ／ＳｉＯ2）が３．５であり、その容量は、７１ｋｇ／溶鋼ｔｏｎであり、溶鋼の温度は、１６５０℃であった。その後、炉体を傾動して出湯を開始した。 100 tons of hot metal was decarburized and smelted in a converter that was used 1500 times or more. The molten slag after completion of blowing had a basicity (CaO / SiO 2 ) of 3.5, a capacity of 71 kg / molten steel ton, and a temperature of the molten steel of 1650 ° C. After that, the furnace body was tilted and hot water was started.
［実施例１］においては、直径が５μｍ〜３０μｍ、長さが３ｍｍ〜１００ｍｍのチョップドファイバー（短繊維）状の酸化物繊維を液相状態の溶融スラグに向けてシュートから投入した。［実施例２］においては、実施例１と同じ酸化物繊維とスラグカットボールを液相状態の溶融スラグに向けてシュートから投入した。 In [Example 1], chopped fiber (short fiber) -like oxide fibers having a diameter of 5 μm to 30 μm and a length of 3 mm to 100 mm were thrown into the molten slag in a liquid phase state from a chute. In [Example 2], the same oxide fibers and slag cut balls as in Example 1 were thrown from the chute toward the molten slag in the liquid phase state.
実施例１、実施例２いずれも、酸化物繊維（及びスラグカットボール）を転炉内に投入してから出湯が完了するまでの時間は、約２分であった。また、比較のため、酸化物繊維を添加しない条件、または平均粒径５ｍｍの生石灰の粒子を添加する条件でも操業を行った。 In both Examples 1 and 2, the time from when the oxide fibers (and slag cut balls) were put into the converter to the completion of hot water discharge was about 2 minutes. For comparison, the operation was also carried out under the condition that no oxide fiber was added or the condition that quicklime particles having an average particle size of 5 mm were added.
かかる操業において、溶融スラグの流出量を以下の方法により算出した。すなわち、取鍋内のスラグの厚さを定規により測定し、取鍋の断面積とスラグの密度を乗じて、溶融スラグの流出量を算出した。さらに、算出した流出量を溶鋼量で割って、溶鋼１ｔｏｎ当たりの溶融スラグ流出量を求めた。さらに、それぞれの期間について１００回試験を行い、各期間における溶融スラグの流出量の平均値を求めた。 In such an operation, the outflow amount of molten slag was calculated by the following method. That is, the thickness of the slag in the ladle was measured with a ruler, and the amount of molten slag outflow was calculated by multiplying the cross-sectional area of the ladle and the density of the slag. Further, the calculated outflow amount was divided by the amount of molten steel to obtain the amount of molten slag outflow per ton of molten steel. Furthermore, the test was carried out 100 times for each period, and the average value of the outflow amount of molten slag in each period was calculated.
［実施例１］（酸化物繊維を投入）
使用した酸化物繊維の種類と添加量、得られた溶融スラグ流出量を表１に示す。比較例である、酸化物繊維も生石灰粒子も添加しない試験Ｎｏ．１においては６．０ｋｇ／ｔの多量のスラグが流出した。試験Ｎｏ．２〜４においては、生石灰粒子の投入量増加に伴い、スラグ流出量は低減しているが、多量の投入量を要している。本発明例である試験Ｎｏ．５〜１６においては、酸化物繊維の投入にともない、生石灰粒子よりも少ない投入量でスラグ流出量が低減している。
[Example 1] (Oxide fiber is added)
Table 1 shows the types and amounts of oxide fibers used and the amount of molten slag outflow obtained. As a comparative example, Test No. in which neither oxide fibers nor quicklime particles were added. In No. 1, a large amount of 6.0 kg / t of slag flowed out. Test No. In Nos. 2 to 4, the amount of slag outflow is reduced as the amount of quicklime particles input is increased, but a large amount of input is required. Test No. which is an example of the present invention. In Nos. 5 to 16, the amount of slag outflow is reduced with the addition of oxide fibers with a smaller amount of input than that of quicklime particles.
［実施例２］（酸化物繊維とスラグカットボールを投入）
酸化物繊維とともに添加するスラグカットボールとして、主要組成が、質量％で、Ｃｒ2Ｏ3：４０％、Ｆｅ2Ｏ3：２５％、ＭｇＯ：１０％、ＳｉＯ2：１０％、Ａｌ2Ｏ3：１０％、残部：不純物である耐火物を用い、内部に鉄芯を装着し、直径２２０ｍｍ、重量２６ｋｇのスラグカットボールを用いた。スラグカットボールの比重は溶鋼と溶融スラグの中間の比重を有している。
[Example 2] (Oxide fiber and slag cut ball are added)
As a slag cut ball to be added together with oxide fibers, the main composition is Cr 2 O 3 : 40%, Fe 2 O 3 : 25%, MgO: 10%, SiO 2 : 10%, Al 2 O 3 in mass%. : 10%, balance: A refractory material that is an impurity was used, an iron core was mounted inside, and a slag cut ball having a diameter of 220 mm and a weight of 26 kg was used. The specific gravity of the slag cut ball is between that of molten steel and molten slag.
使用した酸化物繊維の種類と添加量、得られた溶融スラグ流出量を表２に示す。酸化物繊維もスラグカットボールも添加しない比較例である試験Ｎｏ．１においては６．０ｋｇ／ｔの多量のスラグが流出した。スラグカットボールのみを投入した比較例である試験Ｎｏ．２においては４．０ｋｇ／ｔにまでスラグ流出量が低減した。本発明例である試験Ｎｏ．３〜１４においては、スラグカットボールに加えて酸化物繊維を投入することで、さらにスラグ流出量が低減している。 Table 2 shows the types and amounts of oxide fibers used and the amount of molten slag outflow obtained. Test No. which is a comparative example in which neither oxide fiber nor slag cut ball is added. In No. 1, a large amount of 6.0 kg / t of slag flowed out. Test No. which is a comparative example in which only a slag cut ball was used. In No. 2, the slag outflow amount was reduced to 4.0 kg / t. Test No. which is an example of the present invention. In 3 to 14, the amount of slag outflow is further reduced by adding oxide fibers in addition to the slag cut balls.
Claims (2)
出湯中に、融点が１５００℃以上である酸化物繊維を、転炉内の溶融スラグ表面に投入することを特徴とする転炉内スラグの流出防止方法。 It is a method to prevent the outflow of slag in the converter when the molten iron is taken out from the hot water outlet of the converter.
A method for preventing outflow of slag in a converter, which comprises charging oxide fibers having a melting point of 1500 ° C. or higher onto the surface of molten slag in the converter during hot water discharge.
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| JP2018184645A (en) * | 2017-04-26 | 2018-11-22 | 新日鐵住金株式会社 | Slag outflow prevention apparatus |
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| JPS54104415A (en) * | 1978-02-06 | 1979-08-16 | Kobe Steel Ltd | Slag cut material for discharge of steel |
| JPS60190505A (en) * | 1984-03-09 | 1985-09-28 | Nippon Steel Corp | Slag cutting method during tapping of molten steel |
| JPS6379910A (en) * | 1986-09-24 | 1988-04-09 | Kawasaki Steel Corp | Prevention of slag mixing into tapping steel flow |
| JP2014025305A (en) * | 2012-07-30 | 2014-02-06 | Nittoc Constr Co Ltd | Fiber |
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