JP2009221560A - Method for recycling slag in ladle - Google Patents

Method for recycling slag in ladle Download PDF

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JP2009221560A
JP2009221560A JP2008068643A JP2008068643A JP2009221560A JP 2009221560 A JP2009221560 A JP 2009221560A JP 2008068643 A JP2008068643 A JP 2008068643A JP 2008068643 A JP2008068643 A JP 2008068643A JP 2009221560 A JP2009221560 A JP 2009221560A
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ladle
slag
hot metal
molten iron
remaining
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JP5292870B2 (en
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Shinichi Akai
真一 赤井
Toru Matsuba
透 松葉
Mamoru Suda
守 須田
Kiyotaka Kai
喜代孝 甲斐
Yutaka Ueda
裕 上田
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JFE Steel Corp
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JFE Steel Corp
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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
    • 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

<P>PROBLEM TO BE SOLVED: To effectively utilize slag remaining in a ladle after completing the casting, without raising a recycle-treatment cost and also, without bringing about bad influence to the other operation. <P>SOLUTION: A method for recycling the slag in the ladle is performed as the followings: the slag 1 remaining in the ladle 3 after completing the casting is exhausted into a molten iron ladle 6 for accomodating the molten iron 8 by tilting the above ladle as the hot-state, and the molten iron 8 is discharged as the main raw material for decarburize-refining in a converter from the molten iron ladle under state of leaving the slag in this molten iron ladle and thereafter, the molten iron 10 tapped off from a blast furnace is received with the above molten iron ladle 6 leaving the slag, and after receiving the molten iron, the received molten iron 10 is desulfurized by using the above slag as a part of the desulfurizing agent 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、連続鋳造機などの鋳造工程で鋳造された後の取鍋内に残留するスラグの再利用方法に関し、詳しくは、取鍋内のスラグを溶銑の脱硫剤として再利用する方法に関するものである。   The present invention relates to a method for reusing slag remaining in a ladle after being cast in a casting process such as a continuous casting machine, and more particularly to a method for reusing slag in a ladle as a desulfurizing agent for hot metal. It is.

製鋼所や製鋼工場においては、転炉、電気炉或いはＲＨ真空脱ガス装置などで精錬された溶鋼は取鍋に収容されて連続鋳造機などの鋳造工程に搬送され、鋳造工程で鋳型内に鋳造されて所定の形状の鋳片或いは鋼塊に製造される。取鍋内には、転炉や電気炉での精錬工程で生成したスラグが溶鋼上に存在しており、スラグが鋳型内に注入されると鋳片或いは鋼塊の品質が劣化するので、取鍋底に設置された流出孔からスラグが流出したことを操作員が目視で或いはセンサーが自動的に検知した時点で前記流出孔を閉鎖し、取鍋からの注入を終了している。この場合、取鍋内には溶鋼の一部も残留する。   In steelworks and steelworks, molten steel refined by converters, electric furnaces, or RH vacuum degassing equipment is stored in a ladle and transported to a casting process such as a continuous casting machine, where it is cast into a mold. Thus, a slab or a steel ingot having a predetermined shape is manufactured. In the ladle, the slag produced in the refining process in the converter or electric furnace exists on the molten steel, and when the slag is injected into the mold, the quality of the slab or steel ingot deteriorates. When the operator visually detects that the slag has flowed out from the outflow hole installed in the bottom of the pan or when the sensor automatically detects the slag, the outflow hole is closed and the injection from the ladle is finished. In this case, a part of the molten steel remains in the ladle.

取鍋内に残留した溶鋼及びスラグは、溶鋼は前記流出孔から型枠などに排出され、スラグは取鍋を転倒させることにより、ノロパン（「ノロ鍋」、「スラグ鍋」ともいう）或いはドライピット（「スラグ畠」ともいう）に排出される。残留する溶鋼が少量の場合には、溶鋼もスラグとともにノロパン或いはドライピットに排出される。排出されたスラグは、自然冷却した後に起重機などにより掘り起こされ、且つ破砕機により破砕され、次いで、磁選機により鉄分が除去され後に、埋め立て用材料として埋立地で利用する、或いは路盤用材料として利用するなどされていた（例えば、特許文献１を参照）。但し、このスラグはＣａＯを含有し、自然膨脹性があるために大半が埋め立て用材料としてのみ利用されていた。   Molten steel and slag remaining in the ladle is discharged from the outflow hole to a mold or the like, and the slag is turned over by tumbling the ladle. It is discharged into a pit (also called “slag ridge”). When a small amount of molten steel remains, the molten steel is also discharged into the noropan or dry pit together with the slag. The discharged slag is naturally cooled, dug up by a hoist, etc., and then crushed by a crusher. Then, after iron is removed by a magnetic separator, it is used as a landfill material or used as a roadbed material. (For example, refer to Patent Document 1). However, since this slag contains CaO and is naturally expandable, most of the slag has been used only as a material for landfill.

このスラグの利用範囲を拡大することを目的として、特許文献２には、転炉などから取鍋への出鋼時に、溶鋼トンあたり１〜１０ｋｇの生石灰を取鍋内に添加し、取鍋内での溶鋼の復燐を防止するとともに保温を図り、鋳造後、取鍋内のスラグをノロパンに排出し、冷却後に破砕及び磁選処理して脱燐・脱硫用の副原料に利用することが提案されている。   For the purpose of expanding the range of use of this slag, Patent Document 2 describes that 1-10 kg of quick lime per ton of molten steel is added to the ladle when steel is fed from a converter to a ladle. It is proposed to prevent the dephosphorization of the molten steel in the steel and keep the temperature warm. After casting, the slag in the ladle is discharged into a Noropan, and after cooling it is crushed and magnetically separated for use as a secondary raw material for dephosphorization and desulfurization. Has been.

また、特許文献３には、連続鋳造工程において、取鍋からのスラグの流出に先立って取鍋内に溶鋼を残した状態で取鍋からタンディッシュへの供給を終了し、取鍋内の残溶鋼及びスラグを熱間のまま転炉などの精錬炉へ再装入し、残溶鋼は鉄源として、スラグは造滓剤として利用することが提案されている。特許文献３では、取鍋からスラグが流出しないので、スラグによる鋳片欠陥が回避されるという効果も呈する。
特開昭５５−１１０７０３号公報 特開昭６１−１９４１０７号公報 特開平２−４１７４４号公報 Further, in Patent Document 3, in the continuous casting process, the supply from the ladle to the tundish is terminated with the molten steel left in the ladle prior to the slag flowing out from the ladle. It has been proposed that molten steel and slag are recharged while still hot into a refining furnace such as a converter, and the remaining molten steel is used as an iron source and slag is used as a slagging agent. In patent document 3, since slag does not flow out from a ladle, the effect that the slab defect by slag is avoided is also exhibited.
Japanese Patent Laid-Open No. 55-110703 JP 61-194107 A JP-A-2-41744

しかしながら、上記従来技術には以下の問題点がある。   However, the above prior art has the following problems.

特許文献２では、取鍋内スラグを脱燐剤及び脱硫剤として使用する点で優れるが、スラグを一旦冷却しており、そのために、スラグの破砕処理及び磁選処理が必要であり、リサイクル処理コストが高くなるという問題点がある。また、取鍋からのスラグの排出時にスラグが排出しきれずに大量のスラグが残留した場合には、このスラグにより次回受鋼時の溶鋼の品質が劣化する恐れがあるという問題点もある。   In patent document 2, although it is excellent at the point which uses the slag in a ladle as a dephosphorization agent and a desulfurization agent, the slag is once cooled, Therefore, the crushing process and magnetic separation process of a slag are required, and recycling processing cost There is a problem that becomes high. In addition, when a large amount of slag remains without discharging the slag from the ladle, there is a problem that the quality of the molten steel at the time of receiving steel may deteriorate due to this slag.

特許文献３では、熱間でそのままスラグ及び残溶鋼を転炉などの精錬炉に装入しており、破砕などの工程を必要とせず、特許文献２におけるリサイクル処理コストが高くなるという問題点は解消されるが、スラグのリサイクル回数が増えると、スラグ中の未反応ＣａＯは減少して、転炉精錬の造滓剤として機能しなくなり、新たに添加する造滓剤を減らすことができなくなり、その結果、転炉では大量のスラグ下での精錬を余儀なくされ、転炉精錬の効率が低下するという問題を招く恐れがある。   In Patent Document 3, the slag and residual molten steel are charged as they are in a refining furnace such as a converter in the hot state, and a process such as crushing is not required, and the recycling process cost in Patent Document 2 is high. However, if the number of slag recycling increases, the unreacted CaO in the slag will decrease, and it will not function as a fossilizer for converter refining, and it will not be possible to reduce the newly added fouling agent. As a result, the converter is forced to perform refining under a large amount of slag, which may cause a problem that the efficiency of the converter refining decreases.

本発明は上記事情に鑑みてなされたもので、その目的とするところは、鋳造終了後に取鍋内に残留するスラグを、リサイクル処理コストを高くすることなく、しかも、他の操業に悪影響を及ぼすことなく、有効利用することのできる、取鍋内スラグの再利用方法を提供することである。   The present invention has been made in view of the above circumstances, and the object of the present invention is to adversely affect other operations without increasing the recycling treatment cost of slag remaining in the ladle after completion of casting. It is to provide a method for reusing slag in a ladle that can be used effectively without any problems.

上記課題を解決するための第１の発明に係る取鍋内スラグの再利用方法は、鋳造終了後の取鍋内に残留したスラグを、熱間状態のまま前記取鍋を転倒させて溶銑を収容した溶銑鍋内に排出し、該溶銑鍋に前記スラグを残留させた状態で溶銑鍋から溶銑を転炉脱炭精錬用の主原料として払い出し、その後、スラグを残留させた前記溶銑鍋で高炉から出銑される溶銑を受銑し、受銑後、受銑した溶銑を、前記スラグを脱硫剤の一部として脱硫処理することを特徴とするものである。   The method for reusing slag in a ladle according to the first aspect of the present invention for solving the above-mentioned problem is that the slag remaining in the ladle after the end of casting is tumbled over the ladle while still in a hot state to produce hot metal. The hot metal is discharged into the hot metal ladle, and the hot metal is discharged from the hot metal hot pot as a main raw material for converter decarburization refining in a state where the slag remains in the hot metal hot pot, and then the blast furnace in the hot metal hot pot in which the slag remains. In this case, the hot metal produced from the steel is received, and after receiving, the received hot metal is desulfurized using the slag as a part of the desulfurizing agent.

第２の発明に係る取鍋内スラグの再利用方法は、第１の発明において、取鍋内に残留したスラグを溶銑鍋内に排出する前に、溶銑鍋内にＡｌを含有する脱酸剤を予め添加することを特徴とするものである。   The method for reusing slag in a ladle according to the second invention is the deoxidizer containing Al in the hot metal ladle before discharging the slag remaining in the ladle into the hot metal ladle in the first invention. Is previously added.

第３の発明に係る取鍋内スラグの再利用方法は、第１または第２の発明において、取鍋内に残留したスラグは、Ａｌを含有する脱酸剤または生石灰の添加によって予め改質されたスラグであることを特徴とするものである。   The method for reusing slag in a ladle according to the third invention is the first or second invention, wherein the slag remaining in the ladle is modified in advance by the addition of a deoxidizer or quicklime containing Al. It is characterized by being a slag.

本発明によれば、取鍋内に残留したスラグを熱間状態のまま溶銑鍋に排出するので、排出後に取鍋内に残留するスラグは少なく、この取鍋による次回受鋼時の溶鋼の品質劣化を防止することができる。また、溶銑鍋に排出したスラグを溶銑の脱硫剤の一部として使用するので、溶銑脱硫における脱硫剤の使用量を削減することができるのみならず、スラグは破砕する必要がなく、リサイクルに要するコスト上昇を抑制することができる。しかも、他の操業に悪影響を及ぼすことなく、取鍋内に残留したスラグをリサイクルすることが可能となる。このように本発明によって工業上有益な効果がもたらされる。   According to the present invention, since the slag remaining in the ladle is discharged into the hot metal ladle in a hot state, there is little slag remaining in the ladle after discharge, and the quality of the molten steel at the time of next steel receiving by this ladle Deterioration can be prevented. Moreover, since the slag discharged to the hot metal ladle is used as a part of the hot metal desulfurization agent, not only the amount of desulfurization agent used in the hot metal desulfurization can be reduced, but the slag does not need to be crushed and is required for recycling. An increase in cost can be suppressed. In addition, the slag remaining in the ladle can be recycled without adversely affecting other operations. Thus, the present invention provides an industrially beneficial effect.

以下、添付図面を参照して本発明を具体的に説明する。図１は、本発明に係る取鍋内スラグの再利用方法の工程を示す概略図である。本発明に係る取鍋内スラグの再利用方法は、図１に示す（Ａ）から（Ｅ）の順に一連の工程を実施する。以下、図１の（Ａ）から順に説明する。   Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing steps of a method for reusing slag in a ladle according to the present invention. The method for reusing slag in a ladle according to the present invention performs a series of steps in the order of (A) to (E) shown in FIG. In the following, description will be made in order from FIG.

図１（Ａ）は、取鍋３に収容した溶鋼２を、連続鋳造設備のタンディッシュ４に一旦注入して滞留させ、タンディッシュ４から鋳型５に鋳造している様子を示す図である。取鍋３に収容された溶鋼２の浴面上にはスラグ１が存在する。このスラグ１の主体は、前工程の転炉での精錬工程で生成したスラグが、転炉から溶鋼２を取鍋３に出鋼する際に溶鋼２に混入して流出したもので、スラグ１は、転炉スラグを主成分とし、出鋼後のＡｌやＳｉなどの脱酸で生成した脱酸生成物（酸化物）が加わった、ＣａＯ−ＳｉＯ2−Ａｌ2Ｏ3−ＭｇＯ系組成である。具体的には、ＣａＯ：３５〜５５質量％、ＳｉＯ2：１０〜２０質量％、Ａｌ2Ｏ3：５〜１５質量％、ＭｇＯ：５〜１０質量％、塩基度（質量％ＣａＯ／質量％ＳｉＯ2）が３〜５程度である。 FIG. 1A is a view showing a state in which the molten steel 2 accommodated in the ladle 3 is once poured and retained in the tundish 4 of the continuous casting facility and cast from the tundish 4 to the mold 5. Slag 1 exists on the bath surface of the molten steel 2 accommodated in the ladle 3. The main body of the slag 1 is the slag produced in the refining process in the converter of the previous process, which flows out of the molten steel 2 when the molten steel 2 is taken out from the converter into the ladle 3. Has a CaO—SiO 2 —Al 2 O 3 —MgO composition in which the converter slag is the main component and deoxidation products (oxides) produced by deoxidation such as Al and Si after steel are added. is there. Specifically, CaO: 35 to 55 wt%, SiO 2: 10 to 20 wt%, Al 2 O 3: 5~15 wt%, MgO: 5 to 10 wt%, basicity (wt% CaO / mass% SiO 2) is about 3 to 5.

取鍋３に収容した溶鋼２が少なくなると、取鍋３の内部に溶鋼２の渦流が形成され、この渦流に巻き込まれてスラグ１が溶鋼２とともにタンディッシュ４に流出する。このスラグ１の取鍋３からタンディッシュ４への流出を、電磁気を利用したセンサー、赤外線カメラ、或いは操作員による目視観察などで検知したなら、取鍋３の底部に設置したスライディングノズル１２を閉鎖して取鍋３からタンディッシュ４への注入を終了する。スラグ１は溶鋼２に混入して流出するので、取鍋内には溶鋼２も残留する。特に、スラグ１のタンディッシュ４への流出量を少なくしようとする場合には、溶鋼２の残留量が多くなる。尚、スラグ１が溶鋼２とともにタンディッシュ４に流出する前に、取鍋３に所定量の溶鋼を残留させた状態で、取鍋３からタンディッシュ４への注入を終了しても構わない。鋳造中にロードセルなどで取鍋３の質量を連続して測定することにより、取鍋内の溶鋼質量を求めることができる。   When the molten steel 2 accommodated in the ladle 3 decreases, a vortex flow of the molten steel 2 is formed inside the ladle 3, and the slag 1 flows out to the tundish 4 together with the molten steel 2 by being caught in the vortex flow. If the outflow of the slag 1 from the ladle 3 to the tundish 4 is detected by an electromagnetic sensor, an infrared camera, or visual observation by an operator, the sliding nozzle 12 installed at the bottom of the ladle 3 is closed. Then, the injection from the ladle 3 to the tundish 4 is finished. Since the slag 1 flows into the molten steel 2 and flows out, the molten steel 2 also remains in the ladle. In particular, when the amount of slag 1 flowing out to the tundish 4 is to be reduced, the residual amount of the molten steel 2 is increased. In addition, before the slag 1 flows out into the tundish 4 together with the molten steel 2, the pouring from the ladle 3 to the tundish 4 may be terminated with a predetermined amount of molten steel remaining in the ladle 3. By continuously measuring the mass of the ladle 3 with a load cell or the like during casting, the mass of molten steel in the ladle can be obtained.

取鍋３からタンディッシュ４への注入が終了した以降、連続鋳造設備では、新たな取鍋を用意して連続鋳造を更に継続するか、或いは、タンディッシュ４に残留した溶鋼２の鋳型５への鋳造が終了した時点で鋳造を終了する。   After the pouring from the ladle 3 to the tundish 4 is completed, in the continuous casting facility, a new ladle is prepared and continuous casting is further continued, or to the mold 5 of the molten steel 2 remaining in the tundish 4. When the casting is finished, the casting is finished.

一方、スライディングノズル１２を閉鎖したなら、取鍋３をタンディッシュ４の上方所定位置から直ちに移動させ、取鍋内に残留させたスラグ１が固化完了する前に、取鍋３を、溶銑８を収容し、連続鋳造設備の周辺で台車７に積載されて待機している溶銑鍋６の位置まで搬送する。   On the other hand, if the sliding nozzle 12 is closed, the ladle 3 is immediately moved from a predetermined position above the tundish 4, and the ladle 3 is replaced with the hot metal 8 before the slag 1 remaining in the ladle is solidified. It is accommodated and transported to the position of the hot metal ladle 6 that is loaded on the carriage 7 and is waiting around the continuous casting facility.

そして、図１（Ｂ）に示すように、スラグ１を収容する取鍋３を、溶銑鍋６の上方で転倒させ、取鍋３の上端開口部から残留させた熱間状態のスラグ１を溶銑鍋６に排出する。残留させた溶鋼２もスラグ１と同時に溶銑鍋６に排出する。溶銑鍋６には、予め溶銑鍋６の容量の１／２程度の溶銑８を収容させておく。残留させた溶鋼２は溶銑８に混合して鉄源として回収され、スラグ１は溶銑８の湯面上に滞留する。   And as shown in FIG.1 (B), the ladle 3 which accommodates the slag 1 is overturned above the hot metal ladle 6, and the hot slag 1 left from the upper-end opening part of the ladle 3 is made into hot metal. Drain into pan 6. The remaining molten steel 2 is also discharged into the hot metal ladle 6 simultaneously with the slag 1. In the hot metal ladle 6, hot metal 8 having a capacity of about ½ of the capacity of the hot metal ladle 6 is stored in advance. The remaining molten steel 2 is mixed with the hot metal 8 and recovered as an iron source, and the slag 1 stays on the molten metal surface of the hot metal 8.

ここで、スラグ１を溶銑鍋６に排出する際に、溶銑鍋内の溶銑８に含有される炭素と、スラグ１に含有される低級酸化物（ＦｅＯ、ＭｎＯなど）とが、反応してＣＯガスが発生し、スラグ１の噴出を招くこともあるので、溶銑鍋内の溶銑８の湯面上にＡｌ含有脱酸剤１３を予め上置きして、排出されるスラグ１を脱酸することが好ましい。低級酸化物は優先的にＡｌ含有脱酸剤１３に含有されるＡｌと反応するので、ＣＯガスの発生を防止することができる。Ａｌ含有脱酸剤１３としては、金属Ａｌ、Ｆｅ―Ａｌ合金などを使用できるが、安価であることから金属Ａｌを３０〜５０質量％含有するアルミドロス（「アルミ灰」ともいう）が最適である。   Here, when discharging the slag 1 to the hot metal ladle 6, carbon contained in the hot metal 8 in the hot metal ladle and lower oxides (FeO, MnO, etc.) contained in the slag 1 react to produce CO. Since gas may be generated and the slag 1 may be ejected, an Al-containing deoxidizer 13 is previously placed on the hot metal surface of the hot metal 8 in the hot metal pan to deoxidize the discharged slag 1. Is preferred. Since the lower oxide preferentially reacts with Al contained in the Al-containing deoxidizer 13, generation of CO gas can be prevented. As the Al-containing deoxidizer 13, metal Al, Fe—Al alloy, or the like can be used, but aluminum dross containing 30 to 50% by mass of metal Al (also referred to as “aluminum ash”) is optimal because it is inexpensive. is there.

スラグ１を排出する前に予め脱酸するなどして改質し、スラグ１に含有される低級酸化物を減少させておけば、Ａｌ含有脱酸剤１３の使用量を削減できる、或いはＡｌ含有脱酸剤１３を使用する必要がなくなることから、取鍋内においてスラグ１を予め脱酸することが好ましい。高清浄度鋼の溶製の際には、転炉からの出鋼後にＡｌ含有脱酸剤や生石灰などを取鍋内に添加してスラグ中の低級酸化物を還元或いは減少させる、所謂「スラグ改質」が行われている。従って、スラグ改質の処理が施されたスラグに対して本発明を適用することが望ましい。   The amount of the Al-containing deoxidizer 13 can be reduced by modifying the slag 1 by deoxidizing it before discharging to reduce the lower oxide contained in the slag 1, or the Al content. Since it is not necessary to use the deoxidizer 13, it is preferable to deoxidize the slag 1 in advance in the ladle. When smelting high cleanliness steel, the so-called “slag” is used to reduce or reduce lower oxides in slag by adding Al-containing deoxidizer or quick lime to the ladle after steel from the converter. Reforming "has been carried out. Therefore, it is desirable to apply the present invention to slag that has been subjected to slag reforming treatment.

このようにして、取鍋３に残留させたスラグ１を溶銑鍋６に排出する。１回ないし３回程度のスラグ１の溶銑鍋６への排出を実施し、溶銑鍋６に溶銑８及びスラグ１が或る程度貯まったなら、溶銑鍋内の溶銑８の温度が低下して凝固しないうちに、台車７を転炉設備の周辺に移動させ、溶銑鍋６に収容された溶銑８を装入鍋（図示せず）などの別の容器に払い出す。溶銑８を溶銑鍋６から装入鍋などに払い出す際に、スラグ１の大部分を溶銑鍋６に残留させる。溶銑８は装入鍋から更に転炉に装入され、転炉にて脱炭精錬が施されて、所定組成の溶鋼に仕上げられる。溶銑８を溶銑鍋６から払い出した後の状態を図１（Ｃ）に示す。   In this way, the slag 1 left in the ladle 3 is discharged to the hot metal ladle 6. Once the slag 1 is discharged to the hot metal ladle 6 once to 3 times and the hot metal 8 and the slag 1 are stored to some extent in the hot metal ladle 6, the temperature of the hot metal 8 in the hot metal ladle is lowered and solidified. Before that, the carriage 7 is moved to the periphery of the converter facility, and the hot metal 8 accommodated in the hot metal pan 6 is discharged into another container such as a charging pan (not shown). When the hot metal 8 is discharged from the hot metal pan 6 to the charging pan or the like, most of the slag 1 is left in the hot metal pan 6. The hot metal 8 is further charged into the converter from the charging pan, decarburized and refined in the converter, and finished to a molten steel having a predetermined composition. A state after the hot metal 8 is discharged from the hot metal pan 6 is shown in FIG.

その後、台車７を移動させて溶銑鍋６を高炉鋳床の直下に搬送し、その場で高炉からの溶銑の出銑を待つ。そして、図１（Ｄ）に示すように、高炉から出銑される溶銑１０を、傾注樋９を介して受銑する。傾注樋９は、高炉鋳床に設けられる溶銑樋（図示せず）の延長に設けられる注銑のための慣用の装置である。注入される溶銑１０の熱によってスラグ１の一部は再溶融し、溶銑１０の浴面上に浮遊する。溶銑１０とともに高炉スラグが溶銑鍋６に注入されることもあるが、本発明を実施する上で特段の問題はない。溶銑鍋６で所定量の溶銑１０を受銑したなら、傾注樋９を反対側に傾斜させて溶銑１０の溶銑鍋６への供給を終了する。その後、溶銑１０を収容した溶銑鍋６を脱硫処理設備に搬送する。   Thereafter, the carriage 7 is moved to convey the hot metal ladle 6 directly below the blast furnace casting floor and wait for the hot metal to come out of the blast furnace. Then, as shown in FIG. 1 (D), the hot metal 10 discharged from the blast furnace is received through the tilting iron 9. The tilting iron 9 is a conventional device for pouring provided in the extension of the hot metal (not shown) provided in the blast furnace casting floor. Part of the slag 1 is remelted by the heat of the molten iron 10 injected and floats on the bath surface of the molten iron 10. Although blast furnace slag may be poured into the hot metal ladle 6 together with the hot metal 10, there is no particular problem in carrying out the present invention. When a predetermined amount of hot metal 10 is received in the hot metal ladle 6, the tilting iron 9 is inclined to the opposite side, and the supply of the hot metal 10 to the hot metal pan 6 is terminated. Thereafter, the hot metal ladle 6 containing the hot metal 10 is conveyed to a desulfurization treatment facility.

脱硫処理設備には、図１（Ｅ）に示すように、溶銑鍋内を昇降可能で、軸１１ａを回転軸として回転するインペラー（「攪拌翼」とも呼ぶ）１１が備えられ、また、脱硫剤１４を溶銑鍋６の内部に添加するための、ホッパー、シュートなどからなる脱硫剤添加装置１５が備えられている。この脱硫処理設備は、インペラー１１を溶銑鍋６に収容された溶銑１０に浸漬させ、インペラー１１を回転させて溶銑１０を旋回・攪拌し、この攪拌によって溶銑１０に上置き添加した脱硫剤１４を溶銑１０に巻き込ませ、脱硫処理する設備であり、機械攪拌式脱硫装置とも呼ばれている。   As shown in FIG. 1 (E), the desulfurization processing equipment is provided with an impeller (also referred to as “stirring blade”) 11 that can move up and down in the hot metal ladle and rotates about a shaft 11a, and a desulfurizing agent. A desulfurization agent addition device 15 composed of a hopper, a chute and the like for adding 14 to the hot metal ladle 6 is provided. In this desulfurization treatment equipment, the impeller 11 is immersed in the hot metal 10 accommodated in the hot metal ladle 6, the impeller 11 is rotated, the hot metal 10 is swirled and stirred, and the desulfurizing agent 14 added on the hot metal 10 by this stirring is added. This is a facility for desulfurizing the hot metal 10 and is also called a mechanical stirring desulfurization apparatus.

図１（Ｅ）に示すように、収容する溶銑１０の浴面上にスラグ１が存在した状態で、溶銑鍋６にインペラー１１を浸漬させ、インペラー１１を回転させて溶銑１０の脱硫処理を実施する。インペラー１１の回転に伴ってスラグ１が溶銑１０に巻き込まれ脱硫反応が進行する。スラグ１だけでは脱硫能が小さいので、必要に応じて脱硫剤添加装置１５から脱硫剤１４を添加する。脱硫剤１４としては、ＣａＯ系脱硫剤を使用する。ここで、ＣａＯ系脱硫剤とは、ＣａＯを主成分とし、ＣａＦ2やＡｌ2Ｏ3などを必要に応じて数質量％から十数質量％配合したものである。この場合の脱硫反応は「ＣａＯ＋Ｓ→ＣａＳ＋Ｏ」によって行われる。 As shown in FIG. 1 (E), with the slag 1 existing on the bath surface of the hot metal 10 to be accommodated, the impeller 11 is immersed in the hot metal pan 6 and the impeller 11 is rotated to desulfurize the hot metal 10. To do. As the impeller 11 rotates, the slag 1 is caught in the hot metal 10 and the desulfurization reaction proceeds. Since only the slag 1 has a low desulfurization capacity, the desulfurization agent 14 is added from the desulfurization agent addition device 15 as necessary. As the desulfurizing agent 14, a CaO-based desulfurizing agent is used. Here, the CaO-based desulfurization agent contains CaO as a main component and contains CaF 2 , Al 2 O 3, or the like as needed from several mass% to several tens of mass%. In this case, the desulfurization reaction is performed by “CaO + S → CaS + O”.

尚、溶銑１０の脱硫処理方法には、上記の機械攪拌式脱硫装置を用いた方法の他に、粉体状の脱硫剤を、溶銑中に浸漬させたインジェクションランスから搬送用ガスとともに吹き込んで行う方法や、鉄被覆金属Ｍｇワイヤーを溶銑中に高速度で供給して行うワイヤー・フィーダー法などがあるが、本発明では、溶銑１０の浴面上に浮遊するスラグ１に含有されるＣａＯを脱硫剤の一部として利用することを目的としており、溶銑１０の浴面上に浮遊するスラグ１を溶銑中に巻き込ませるためには機械攪拌式脱硫装置が優れており、従って、機械攪拌式脱硫装置を用いて脱硫処理することが好ましい。   In addition to the method using the mechanical stirring type desulfurization apparatus described above, the desulfurization treatment method for the hot metal 10 is performed by blowing a powdery desulfurization agent together with a conveying gas from an injection lance immersed in the hot metal. In this invention, there is a method of desulfurizing CaO contained in the slag 1 floating on the bath surface of the hot metal 10. The mechanical stirring type desulfurization device is excellent in order to entrain the slag 1 floating on the bath surface of the hot metal 10 in the hot metal. Desulfurization treatment is preferably performed using

インペラー１１による攪拌を所定の時間実施したなら、インペラー１１を停止し、インペラー１１を溶銑１０の上方に上昇させる。溶銑中に懸濁した、スラグ１を始めとする脱硫剤１４は、脱硫スラグとなって溶銑浴面に浮上し、脱硫処理が終了する。脱硫処理後、生成した脱硫スラグを溶銑鍋６から排出し、溶銑１０を収容した溶銑鍋６を次工程の転炉設備或いは溶銑予備脱燐設備に搬送する。   When the stirring by the impeller 11 is performed for a predetermined time, the impeller 11 is stopped and the impeller 11 is raised above the hot metal 10. The desulfurization agent 14 including the slag 1 suspended in the hot metal becomes desulfurization slag and floats on the hot metal bath surface, and the desulfurization process is completed. After the desulfurization treatment, the generated desulfurization slag is discharged from the hot metal ladle 6, and the hot metal ladle 6 containing the hot metal 10 is conveyed to a converter or hot metal preliminary dephosphorization facility in the next step.

このように、本発明によれば、取鍋内に残留したスラグ１を熱間状態のまま溶銑鍋６に排出するので、排出後に取鍋内に残留するスラグは少なく、この取鍋による次回受鋼時の溶鋼の品質劣化を防止することができる。また、溶銑鍋に排出したスラグ１を溶銑１０の脱硫剤１４の一部として使用するので、溶銑脱硫における脱硫剤の使用量を削減することができるのみならず、スラグは破砕する必要がなく、リサイクルに要するコスト上昇を抑制することができる。   Thus, according to the present invention, since the slag 1 remaining in the ladle is discharged to the hot metal ladle 6 in a hot state, there is little slag remaining in the ladle after the discharge, and the next receiving by this ladle. It is possible to prevent the deterioration of the quality of the molten steel at the time of steel. Moreover, since the slag 1 discharged to the hot metal ladle is used as a part of the desulfurizing agent 14 of the hot metal 10, not only can the amount of desulfurizing agent used in the hot metal desulfurization be reduced, but the slag does not need to be crushed, Cost increase required for recycling can be suppressed.

具体的には、本発明を適用することによって、取鍋内に付着残留するスラグ１の量は、取鍋あたり２００ｋｇ以下に低減され、付着量が少なく残留スラグが実質的にゼロの場合も発生する。従来、残留した溶鋼２を先ず型枠などに排出させ、その後スラグ１をドライピットなどに排出していた場合には、取鍋あたり５００ｋｇ程度が付着しており、付着スラグは大幅に削減されたことが分かる。また、溶銑の脱流処理において、ＣａＯ系脱硫剤の使用量は、スラグ１をリサイクルしない場合には９ｋｇ／ｔであったが、スラグ１をリサイクルすることによって６ｋｇ／ｔ程度になり、およそ３ｋｇ／ｔのＣａＯ系脱硫剤の削減が達成されている。   Specifically, by applying the present invention, the amount of slag 1 remaining in the ladle is reduced to 200 kg or less per ladle, and the amount of adhesion is small and the residual slag is substantially zero. To do. Conventionally, when the remaining molten steel 2 is first discharged into a mold or the like, and then the slag 1 is discharged into a dry pit or the like, about 500 kg is attached per ladle, and the attached slag is greatly reduced. I understand that. In addition, in the hot metal desulfurization treatment, the amount of CaO-based desulfurizing agent used is 9 kg / t when the slag 1 is not recycled, but becomes about 6 kg / t by recycling the slag 1, and is about 3 kg. Reduction of CaO-based desulfurization agent of / t has been achieved.

本発明に係る取鍋内スラグの再利用方法の工程を示す概略図である。It is the schematic which shows the process of the reuse method of the slag in a ladle concerning this invention.

符号の説明Explanation of symbols

１ スラグ
２ 溶鋼
３ 取鍋
４ タンディッシュ
５ 鋳型
６ 溶銑鍋
７ 台車
８ 溶銑
９ 傾注樋
１０ 溶銑
１１ インペラー
１２ スライディングノズル
１３ Ａｌ含有脱酸剤
１４ 脱硫剤
１５ 脱硫剤添加装置 DESCRIPTION OF SYMBOLS 1 Slag 2 Molten steel 3 Ladle 4 Tundish 5 Mold 6 Hot metal ladle 7 Carriage 8 Hot metal 9 Tilting iron 10 Hot metal 11 Impeller 12 Sliding nozzle 13 Al containing deoxidizer 14 Desulfurizer 15 Desulfurizer addition device

Claims (3)

鋳造終了後の取鍋内に残留したスラグを、熱間状態のまま前記取鍋を転倒させて溶銑を収容した溶銑鍋内に排出し、該溶銑鍋に前記スラグを残留させた状態で溶銑鍋から溶銑を転炉脱炭精錬用の主原料として払い出し、その後、スラグを残留させた前記溶銑鍋で高炉から出銑される溶銑を受銑し、受銑後、受銑した溶銑を、前記スラグを脱硫剤の一部として脱硫処理することを特徴とする、取鍋内スラグの再利用方法。   The slag remaining in the ladle after completion of casting is discharged into the hot metal ladle containing the hot metal by tumbling the ladle in a hot state, and the slag remains in the hot metal ladle. The hot metal discharged from the blast furnace from the blast furnace is received in the hot metal ladle in which the slag remains, and the received hot metal is received by the slag. A method for reusing slag in a ladle, characterized in that desulfurization treatment is performed as a part of the desulfurizing agent. 取鍋内に残留したスラグを溶銑鍋内に排出する前に、溶銑鍋内にＡｌを含有する脱酸剤を予め添加することを特徴とする、請求項１に記載の取鍋内スラグの再利用方法。   The slag in a ladle according to claim 1, wherein a deoxidizer containing Al is added in advance to the hot metal ladle before discharging the slag remaining in the ladle into the hot metal ladle. How to Use. 取鍋内に残留したスラグは、Ａｌを含有する脱酸剤または生石灰の添加によって予め改質されたスラグであることを特徴とする、請求項１または請求項２に記載の取鍋内スラグの再利用方法。   3. The slag in a ladle according to claim 1, wherein the slag remaining in the ladle is slag that has been modified in advance by addition of a deoxidizer containing Al or quick lime. How to reuse.
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KR101185226B1 (en) 2010-06-28 2012-09-21 현대제철 주식회사 Method of desulfuration treatment of return molten steel
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CN103639401A (en) * 2013-12-16 2014-03-19 江苏大学 Ladle slag removal agent, preparation method and use method
CN114317870A (en) * 2020-09-29 2022-04-12 宝山钢铁股份有限公司 Method for directly returning hot-state casting residue to converter
CN114934150A (en) * 2022-06-29 2022-08-23 莱芜钢铁集团银山型钢有限公司 System and method for reducing amount of slag poured into steel ladle in converter tapping process
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KR101185240B1 (en) 2010-06-28 2012-09-21 현대제철 주식회사 Method of desulfuration of return molten steel using slag made in KR desulfuration process
KR101185226B1 (en) 2010-06-28 2012-09-21 현대제철 주식회사 Method of desulfuration treatment of return molten steel
CN102719622A (en) * 2011-03-29 2012-10-10 鞍钢股份有限公司 Method for recycle of steel-making casting-remnant heat-state steel slag
CN103639401A (en) * 2013-12-16 2014-03-19 江苏大学 Ladle slag removal agent, preparation method and use method
CN114317870A (en) * 2020-09-29 2022-04-12 宝山钢铁股份有限公司 Method for directly returning hot-state casting residue to converter
CN114934150A (en) * 2022-06-29 2022-08-23 莱芜钢铁集团银山型钢有限公司 System and method for reducing amount of slag poured into steel ladle in converter tapping process
CN114934150B (en) * 2022-06-29 2023-06-23 莱芜钢铁集团银山型钢有限公司 System and method for reducing slag quantity injected into steel ladle in converter tapping process
CN115505671A (en) * 2022-08-04 2022-12-23 包头钢铁（集团）有限责任公司 Method for recycling hot-state casting residues of non-oriented silicon steel

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