TW201416456A - Refine method of hot metal - Google Patents
Refine method of hot metal Download PDFInfo
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- TW201416456A TW201416456A TW102138986A TW102138986A TW201416456A TW 201416456 A TW201416456 A TW 201416456A TW 102138986 A TW102138986 A TW 102138986A TW 102138986 A TW102138986 A TW 102138986A TW 201416456 A TW201416456 A TW 201416456A
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/56—Manufacture of steel by other methods
- C21C5/562—Manufacture of steel by other methods starting from scrap
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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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- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
Description
本發明是關於鐵水的精煉方法,該精煉方法至少使用2個轉爐型精煉爐,將其中一者用作鐵水的預處理精煉爐(hot metal pretreatment furnace),且將另一者用作在預處理精煉爐中進行了預處理的鐵水的脫碳精煉爐而自鐵水熔煉鋼水。詳細而言,本發明是關於將在脫碳精煉爐中產生的熔融爐渣(slag)維持高溫狀態來用作預處理精煉爐中的精煉劑的精煉方法。 The present invention relates to a refining method for molten iron using at least two converter type refining furnaces, one of which is used as a hot metal pretreatment furnace, and the other is used as The pretreated refining furnace is subjected to a pretreatment hot metal decarburization refining furnace to melt molten steel from molten iron. In particular, the present invention relates to a refining method for using a molten slag (slag) generated in a decarburization refining furnace to maintain a high temperature state as a refining agent in a pretreatment refining furnace.
在鋼鐵製造步驟的各步驟中,進行應對要求各種鋼材高品質化及低價格化的技術開發。在自鐵水熔煉鋼水的精煉步驟中,為了使藉由精煉而自熔融金屬相轉移、分離為熔融爐渣相的雜質成分在其以後的精煉步驟中不返回至熔融金屬相,而在精煉結束後的湧出作業時進行操作,以使在該精煉過程中生成的熔融爐渣儘量不流出至鐵水鍋或鋼包等熱液接收容器。即,在精煉爐的湧出作業中以如下方式進行湧出作業,即,儘量將熔融金屬全部自精煉爐排出至熱液接收容器,另一方面,儘量使熔融爐渣殘留在精煉爐中。 In each step of the steel manufacturing step, technical development is required to meet the demand for high quality and low price of various steel materials. In the refining step of molten steel from molten iron, the impurity component which is transferred from the molten metal phase by the refining and separated into the molten slag phase is not returned to the molten metal phase in the subsequent refining step, but is refined. The operation is performed at the time of the completion of the gushing operation so that the molten slag generated in the refining process does not flow out to the hot liquid receiving container such as a hot metal pot or a ladle as much as possible. In other words, in the pouring operation of the refining furnace, the gating operation is performed in such a manner that all of the molten metal is discharged from the refining furnace to the hot liquid receiving container as much as possible, and the molten slag is left as much as possible in the refining furnace.
通常,殘留在精煉爐內的熔融爐渣自精煉爐排出至渣桶 (slag pot:爐渣接收容器),並利用渣桶搬送至渣場(slag yard),且流出至渣場中而在大氣中放置冷卻。然而,近年來,自重複使用爐渣或有效利用爐渣所保有的熱等的觀點考慮,殘留在精煉爐內的熔融爐渣的有效的處理方法成為課題。又,在湧出作業中,不可能使熔融金屬與熔融爐渣完全分離,因此會在湧出結束後的精煉爐內殘留有少量的熔融金屬。因此,亦期望對爐內殘留的熔融金屬進行有效的處理。 Usually, the molten slag remaining in the refining furnace is discharged from the refining furnace to the slag bucket (slag pot: slag receiving container), and transported to a slag yard by a slag bucket, and discharged into a slag yard to be placed in the atmosphere to be cooled. However, in recent years, an effective treatment method of the molten slag remaining in the refining furnace has been a problem from the viewpoint of reusing the slag or utilizing the heat retained by the slag. Further, in the gushing operation, it is impossible to completely separate the molten metal from the molten slag, so that a small amount of molten metal remains in the refining furnace after the completion of the gushing. Therefore, it is also desirable to effectively treat the molten metal remaining in the furnace.
以往,作為利用鐵水的脫碳精煉中所生成的轉爐爐渣(亦稱為「脫碳爐渣」)的方法,尤其是關於在使用作為預處理而對鐵水實施了脫磷處理的磷濃度低的鐵水(亦稱為「低磷鐵水」)的脫碳精煉中所生成的熔融爐渣,提出有幾個將其作為精煉劑來重複利用的方法。 Conventionally, as a method of using converter slag (also referred to as "decarburization slag") produced by decarburization refining of molten iron, in particular, the phosphorus concentration of dephosphorization treatment of molten iron as a pretreatment is low. The molten slag produced in the decarburization refining of molten iron (also referred to as "low-phosphorus molten iron") has been proposed to be reused as a refining agent.
例如,專利文獻1中揭示有如下煉鋼方法:將2個轉爐型精煉爐中的其中一者用作脫磷精煉爐,且將另一者用作脫碳精煉爐,將在脫磷精煉爐中實施了脫磷處理的鐵水在脫碳精煉爐中的脫碳精煉中所生成的轉爐爐渣加以暫時回收,並將所回收的轉爐爐渣作為精煉劑添加至脫磷精煉爐中,藉此來削減在脫磷處理時新添加的精煉劑、及利用精煉劑的渣化促進來促進脫磷反應。 For example, Patent Document 1 discloses a steelmaking method in which one of two converter-type refining furnaces is used as a dephosphorization refining furnace, and the other is used as a decarburization refining furnace, which will be in a dephosphorization refining furnace. The converter slag produced by the dephosphorization treatment of the molten iron in the decarburization refining furnace is temporarily recovered, and the recovered converter slag is added as a refining agent to the dephosphorization refining furnace. The refining agent newly added during the dephosphorization treatment and the slag promoting by the refining agent are reduced to promote the dephosphorization reaction.
專利文獻2中揭示如下精煉方法:將實施了脫磷處理的鐵水在脫碳精煉爐中的脫碳精煉中所生成的脫碳爐渣排出至其他收納有鐵水的鐵水保持容器,其後,將排出至鐵水保持容器中的熔融狀態的脫碳爐渣、及預先收納在鐵水保持容器中的鐵水裝入 至脫磷精煉爐中,對裝入至脫磷精煉爐中的鐵水實施脫磷處理,藉此,對熔融狀態的脫碳爐渣進行熱重複使用。 Patent Document 2 discloses a refining method in which decarburization slag produced by decarburization refining of molten iron subjected to dephosphorization treatment in a decarburization refining furnace is discharged to another molten iron holding container containing molten iron, and thereafter The decarburization slag discharged into the molten state in the molten iron holding container and the molten iron previously stored in the molten iron holding container are loaded In the dephosphorization refining furnace, the molten iron charged in the dephosphorization refining furnace is subjected to dephosphorization treatment, whereby the decarburized slag in a molten state is thermally reused.
專利文獻3中揭示如下轉爐煉鋼法,即在如下般重複五個步驟來實施的轉爐煉鋼法中,為了防止第五步驟中殘留的爐渣暴沸,而向第五步驟中殘留的爐渣添加含有大量氧化鐵的冷卻材料,上述五個步驟是如下般重複:首先進行將鐵水或以鐵水與鐵渣(scrap)為主原料裝入至轉爐的第一步驟,繼而實施進行脫矽、脫磷的第二步驟,然後對所生成的爐渣進行的第三步驟,其後實施進行脫碳精煉的第四步驟,其次在脫碳精煉後進行使爐渣殘留而湧出鋼水的第五步驟,其後返回至第一步驟,且在第二步驟的脫矽、脫磷中再循環使用第五步驟中殘留的爐渣。 Patent Document 3 discloses a converter steelmaking method in which a slag remaining in the fifth step is added in order to prevent the slag which is left in the fifth step from being bumped in the converter steelmaking method which is carried out by repeating five steps as follows. For the cooling material containing a large amount of iron oxide, the above five steps are repeated as follows: first, the first step of charging molten iron or molten iron and iron scrap as a main raw material into the converter is carried out, followed by dislocation, a second step of dephosphorization, then a third step of the generated slag, followed by a fourth step of decarburization refining, and a fifth step of dehydrating and refining the molten slag after the decarburization refining, Thereafter, the process returns to the first step, and the slag remaining in the fifth step is recycled in the decarburization and dephosphorization of the second step.
專利文獻1:日本專利特開平3-115515號公報 Patent Document 1: Japanese Patent Laid-Open No. Hei 3-115515
專利文獻2:日本專利特開2001-172710號公報 Patent Document 2: Japanese Patent Laid-Open Publication No. 2001-172710
專利文獻3:日本專利特開2001-192720號公報 Patent Document 3: Japanese Patent Laid-Open Publication No. 2001-192720
然而,上述現有技術存在以下問題。 However, the above prior art has the following problems.
即,專利文獻1中,將殘留在脫碳精煉爐內的熔融爐渣暫時回收,並在破碎處理後加以使用,因此並未回收爐渣所具有的熱量。又,在自脫碳精煉爐排出熔融爐渣時,將殘留在脫碳精煉爐內的鋼水與熔融爐渣一同排出至精煉製程系統外而進行處 理,因此成為導致鋼水產率惡化的一因素。 In other words, in Patent Document 1, the molten slag remaining in the decarburization refining furnace is temporarily recovered and used after the crushing treatment, so that the heat of the slag is not recovered. Further, when the molten slag is discharged from the decarburization refining furnace, the molten steel remaining in the decarburization refining furnace is discharged together with the molten slag to the outside of the refining process system. Therefore, it is a factor that causes the deterioration of molten steel yield.
專利文獻2中,必須將收納鐵水的鐵水保持容器配置在脫碳精煉爐的鉛直方向正下方,有時因爐正下方的高度限制而無法實施。又,在可實施的情形時,亦會因向脫碳精煉爐的正下方配置鐵水保持容器,或使接收爐渣之後的鐵水保持容器移動至脫磷精煉爐而自鐵水保持容器將鐵水裝入至脫磷精煉爐等,而使得鐵水保持容器的移動頻繁且複雜,易於產生時間損失,因而成為引起生產量降低或鐵水溫度降低的原因。進而,若排出至鐵水保持容器中的熔融爐渣或未脫氧的鋼水捲入至鐵水中,則有急遽產生CO氣體而暴沸的危險,且亦有安全上的問題。 In Patent Document 2, it is necessary to dispose the molten iron container that accommodates molten iron directly below the vertical direction of the decarburization refining furnace, which may not be performed due to the height restriction immediately below the furnace. Further, in the case where it can be carried out, the molten iron holding container is disposed directly under the decarburization refining furnace, or the molten iron holding container after receiving the slag is moved to the dephosphorization refining furnace, and the iron is retained from the molten iron holding container. The water is charged into the dephosphorization refining furnace or the like, so that the movement of the molten iron holding container is frequent and complicated, and it is easy to cause a time loss, which causes a decrease in the production amount or a decrease in the temperature of the molten iron. Further, when the molten slag discharged into the molten iron holding container or the molten steel which is not deoxidized is taken up into the molten iron, there is a risk that the CO gas is suddenly generated and bumped, and there is also a safety problem.
專利文獻3中,在1個轉爐型精煉爐中連續進行自鐵水的脫磷處理至脫碳精煉的操作,雖可防止伴隨湧出鋼水的放熱,但在轉爐型精煉爐內的滯留時間變長,從而轉爐型精煉爐的生產性降低。又,脫磷處理可在爐體耐火物的負荷輕的低溫溫度帶進行,但由於串列地進行自脫磷處理至脫碳精煉的操作,因此在爐體耐火物無法承受成為1650℃以上的高溫狀態的脫碳精煉的情形時,必須對爐體耐火物加以修改,因而有耐火物成本上升的問題。又,為了使熔融狀態的脫碳爐渣固化而添加大量氧化鐵,因該氧化鐵的還原所需的熱量而導致額外的熱損耗增大,並且亦產生因所添加的氧化鐵而導致爐體耐火物的損耗增加的問題。進而,即便在脫磷處理後排渣,亦有在脫磷處理中生成的含有2質量%左右的磷的爐渣的一部分殘留在爐內,且在其後的脫碳精煉中復磷 (rephosphorization:爐渣中的磷轉移至鐵水或鋼水中而導致鐵水或鋼水中的磷濃度上升的現象)的問題。 In Patent Document 3, the dephosphorization treatment from the molten iron to the decarburization refining operation is continuously performed in one converter type refining furnace, and the heat generation accompanying the molten steel can be prevented, but the residence time in the converter type refining furnace is changed. The production capacity of the converter type refining furnace is reduced. Further, the dephosphorization treatment can be carried out in a low-temperature temperature zone in which the load of the refractory body of the furnace is light, but since the operation from the dephosphorization treatment to the decarburization refining is performed in series, the refractory of the furnace body cannot withstand 1650 ° C or more. In the case of decarburization refining in a high temperature state, it is necessary to modify the refractory of the furnace body, and thus there is a problem that the cost of the refractory increases. Further, in order to solidify the decarburized slag in a molten state, a large amount of iron oxide is added, and the heat loss required for the reduction of the iron oxide causes an increase in additional heat loss, and the furnace body is also refractory due to the added iron oxide. The problem of increased loss of matter. Further, even if slag is discharged after the dephosphorization treatment, a part of the slag containing about 2% by mass of phosphorus generated in the dephosphorization treatment remains in the furnace, and the phosphorus is removed in the subsequent decarburization refining. (rephosphorization: a problem in which phosphorus in slag is transferred to molten iron or molten steel to cause an increase in phosphorus concentration in molten iron or molten steel).
本發明是鑒於上述情況而完成者,其目的在於提供一種鐵水的精煉方法,該精煉方法在至少使用2個轉爐型精煉爐,將其中一者用作鐵水的預處理精煉爐,且將另一者用作在預處理精煉爐中進行了預處理的鐵水的脫碳精煉爐而自鐵水熔煉鋼水時,不損害預處理精煉爐及脫碳精煉爐的生產性,而可將在脫碳精煉爐中產生的熔融爐渣維持高溫狀態來用作預處理精煉爐中的精煉劑。 The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for refining molten iron, which uses at least two converter type refining furnaces, one of which is used as a pretreatment refining furnace for molten iron, and The other is used as a decarburization refining furnace for pretreatment of molten iron in a pretreatment refining furnace, and does not impair the productivity of the pretreatment refining furnace and the decarburization refining furnace when molten steel is molten from molten iron. The molten slag produced in the decarburization refining furnace is maintained at a high temperature to be used as a refining agent in the pretreatment refining furnace.
本發明者等為了解決上述課題而積極地進行試驗研究,結果獲得以下見解。 The inventors of the present invention actively conducted experimental research in order to solve the above problems, and as a result, obtained the following findings.
即,作為高效地利用在脫碳精煉爐進行鐵水的脫碳精煉之後,在熔煉的鋼水湧出時殘留在脫碳精煉爐內的熔融爐渣的顯熱的方法,有效的是如下方法,即,將該熔融爐渣維持高溫狀態而在最近的預處理精煉爐中所進行的預處理中用作精煉劑。為此,必須防止上述熔融爐渣(以下,亦記為「脫碳爐渣」)、或與熔融爐渣一同殘留在脫碳精煉爐內的未脫氧的鋼水,在與裝入至預處理精煉爐中的鐵水接觸的瞬間急遽反應而噴出鐵水或爐渣或火焰從而妨礙作業,並且最大限度地利用該等所具有的熱能來用於鐵渣等鐵源的熔解。 In other words, as a method of efficiently utilizing the sensible heat of the molten slag remaining in the decarburization refining furnace after the molten steel is poured out in the decarburization refining furnace, it is effective to use the following method. The molten slag is maintained at a high temperature and used as a refining agent in the pretreatment performed in the recent pretreatment refining furnace. Therefore, it is necessary to prevent the molten slag (hereinafter also referred to as "decarburization slag") or the undeoxidized molten steel remaining in the decarburization refining furnace together with the molten slag, and to be loaded into the pretreatment refining furnace. The rapid contact of the molten iron contacts the molten iron or the slag or the flame to impede the operation, and utilizes the heat energy of the steel to maximize the melting of the iron source such as iron slag.
因此,使上述熔融爐渣以自積層的鐵渣上維持熔融狀態流下而使上述爐渣的至少一部分凝固的方式,與鐵渣熱交換來降 低上述爐渣的反應性。即,發現有效的是,使上述爐渣在使反應性降低之後與裝入至預處理精煉爐中的鐵水接觸,將上述爐渣與藉由和上述爐渣的熱交換而預熱的鐵渣一同用於預處理精煉爐中的鐵水預處理。 Therefore, the molten slag is cooled by heat exchange with the iron slag by allowing the molten iron slag to flow down from the iron slag of the build-up layer to solidify at least a part of the slag. The reactivity of the above slag is low. That is, it has been found to be effective to bring the slag into contact with the molten iron charged in the pretreatment refining furnace after reducing the reactivity, and to use the slag together with the iron slag preheated by heat exchange with the slag. Pretreatment of molten iron in a pretreatment refining furnace.
如此般進行了處理的上述熔融爐渣及上述鋼水,即便與鐵水接觸亦不會產生急遽反應的問題,又,與將石灰石等作為冷卻材料的情形不同,亦不會有固化為大塊而妨礙渣化的問題,因此即便在相對低溫的鐵水的預處理中亦可有效地活用作精煉劑。 The molten slag and the molten steel thus treated have no problem of rapid reaction even if they are in contact with molten iron, and do not solidify into a large block unlike the case where limestone or the like is used as a cooling material. The problem of slag formation is hindered, so that it can be effectively used as a refining agent even in the pretreatment of relatively low-temperature molten iron.
又,上述熔融爐渣的成分組成亦必須為適於其最近的預處理者,且亦必須有效地利用。即,為了有效利用脫碳爐渣,而必須將脫碳爐渣的熱處理操作及其成分組成這兩者控制為適當。此處,預處理是指脫矽處理或脫磷處理。作為脫磷處理,包含對經脫矽處理的鐵水進行脫磷的精煉、及對未進行脫矽處理的鐵水進行脫矽處理、脫磷處理的精煉。在脫磷處理中,連續進行脫矽處理與脫磷處理的處理亦記為脫矽、脫磷處理。 Further, the composition of the molten slag must also be suitable for the most recent pretreatment, and must also be effectively utilized. That is, in order to effectively utilize the decarburization slag, it is necessary to control both the heat treatment operation of the decarburization slag and the component composition thereof as appropriate. Here, the pretreatment refers to a depurination treatment or a dephosphorization treatment. The dephosphorization treatment includes refining for dephosphorization of the distorted molten iron, and refining of the molten iron which has not been subjected to the deodorization treatment, and dephosphorization treatment. In the dephosphorization treatment, the treatment of continuously performing the depurination treatment and the dephosphorization treatment is also referred to as dislocation and dephosphorization treatment.
為了滿足上述條件,作為用於脫碳精煉的鐵水,較佳為使用將磷濃度低磷化至0.030質量%左右以下、理想的是低磷化至0.020質量%以下的脫磷鐵水(低磷鐵水)。藉由對該低磷鐵水進行脫碳精煉,而易於生成磷濃度低的脫碳爐渣,因此,可將該脫碳爐渣用作脫矽處理時的爐渣的鹼度調整劑的一部分或全部,及用作脫磷處理用的精煉劑的一部分或全部。該情形時重要的是,將殘留在脫碳精煉爐內的脫碳爐渣在排出至爐渣收納搬送容器之 後,不實施水冷處理等便用於最近的預處理,以最大限度地利用脫碳爐渣所保有的顯熱。本發明中,爐渣的鹼度為以爐渣中的CaO濃度與SiO2濃度的比((質量%CaO)/(質量%SiO2))來表示的值。 In order to satisfy the above conditions, as the molten iron for decarburization refining, it is preferred to use dephosphorized molten iron having a low phosphorus concentration to about 0.030 mass% or less, and preferably low phosphating to 0.020 mass% or less. Phosphate iron). By decarburizing and refining the low-phosphorus molten iron, it is easy to form a decarburization slag having a low phosphorus concentration. Therefore, the decarburization slag can be used as a part or all of the alkalinity adjuster of the slag during the deodorization treatment. And used as part or all of the refining agent for dephosphorization treatment. In this case, it is important that the decarburization slag remaining in the decarburization refining furnace is discharged to the slag storage and transportation container, and is used for the most recent pretreatment without performing water cooling treatment or the like to maximize the utilization of the decarburization slag. The sensible heat of possession. In the present invention, the alkalinity of the slag is a value expressed by the ratio of the CaO concentration in the slag to the SiO 2 concentration ((% by mass CaO) / (% by mass SiO 2 )).
藉此,發現可高效地回收鐵水的脫碳精煉結束後的熔融爐渣的顯熱。又亦發現在脫碳精煉後鋼水自脫碳精煉爐湧出,但若在脫碳精煉爐內殘留有鋼水,且將該殘留的鋼水與熔融爐渣一同用於預處理,則會有利於回收其顯熱及鐵成分。 Thereby, it was found that the sensible heat of the molten slag after the completion of the decarburization refining of the molten iron can be efficiently recovered. It has also been found that the molten steel flows out of the decarburization refining furnace after decarburization refining, but if molten steel remains in the decarburization refining furnace, and the residual molten steel is used together with the molten slag for pretreatment, it is advantageous. Recover its sensible heat and iron composition.
本發明是基於上述見解而完成者,其主旨為如下所述。 The present invention has been completed based on the above findings, and the gist thereof is as follows.
[1]一種鐵水的精煉方法,其特徵在於:至少使用2個轉爐型精煉爐,將其中一者用作鐵水的預處理精煉爐,且將另一者用作在上述預處理精煉爐中進行了預處理的鐵水的脫碳精煉爐而自鐵水熔煉鋼水,且在將藉由上述脫碳精煉爐中的脫碳精煉而獲得的鋼水湧出至鋼包中之後,使殘留在脫碳精煉爐內的爐渣自積層的鐵渣上維持熔融狀態流下而使上述爐渣的至少一部分凝固,其後,在上述預處理精煉爐中的鐵水的預處理中,將至少一部分凝固的上述爐渣與上述鐵渣一同維持高溫而使用。 [1] A method for refining molten iron, characterized in that at least two converter type refining furnaces are used, one of which is used as a pretreatment refining furnace for molten iron, and the other is used as the pretreatment refining furnace described above. The molten iron decarburization refining furnace in which the pretreatment is performed, and the molten steel is melted from the molten iron, and after the molten steel obtained by the decarburization refining in the decarburization refining furnace is poured out into the ladle, The slag remaining in the decarburization refining furnace is maintained in a molten state by the molten iron slag, and at least a part of the slag is solidified, and thereafter, at least a part of the molten iron in the pretreatment refining furnace is solidified. The slag described above is used together with the iron slag to maintain a high temperature.
[2]如上述[1]記載的鐵水的精煉方法,其中將殘留在上述脫碳精煉爐內的爐渣排出至預先裝入有鐵渣的爐渣收納搬送容器,並使該爐渣自積層在該爐渣收納搬送容器內的上述鐵渣上維持熔融狀態流下而使上述爐渣的至少一部分凝固,其次,將收納在上述爐渣收納搬送容器中的至少一部分凝固的上述爐渣與上述鐵渣一 同裝入至上述預處理精煉爐中,其後,將鐵水裝入至該預處理精煉爐中而對該鐵水進行預處理。 [2] The method for refining molten iron according to the above [1], wherein the slag remaining in the decarburization refining furnace is discharged to a slag storage transfer container in which iron slag is previously loaded, and the slag is self-assembled. The iron slag in the slag storage and transport container is kept in a molten state and at least a part of the slag is solidified, and then at least a part of the slag which is stored in the slag storage and transport container is solidified, and the iron slag is The molten iron was pretreated by being charged into the pretreatment refining furnace, and then charged into the pretreatment refining furnace.
[3]如上述[1]記載的鐵水的精煉方法,其中將殘留在上述脫碳精煉爐內的爐渣排出至爐渣收納搬送容器中,其次,將收納在該爐渣收納搬送容器中的上述爐渣裝入至預先裝入有鐵渣的上述預處理精煉爐中,至少使上述爐渣的一部分自積層在該預處理精煉爐內的上述鐵渣上維持熔融狀態流下而使上述爐渣的至少一部分凝固,其後,將鐵水裝入至上述預處理精煉爐而對該鐵水進行預處理。 [3] The method for refining molten iron according to the above [1], wherein the slag remaining in the decarburization refining furnace is discharged to the slag storage and transport container, and the slag contained in the slag storage and transport container is next Loading into the pretreatment refining furnace in which the iron slag is preliminarily loaded, and at least a part of the slag is allowed to flow in the molten state on the iron slag in the pretreatment refining furnace to cause at least a part of the slag to solidify. Thereafter, molten iron is charged into the above pretreatment refining furnace to pretreat the molten iron.
[4]如上述[3]記載的鐵水的精煉方法,其中上述爐渣收納搬送容器在其內表面側佈設有耐火物層。 [4] The method for refining molten iron according to the above [3], wherein the slag storage container is provided with a refractory layer on the inner surface side thereof.
[5]如上述[1]至上述[4]中任一項記載的鐵水的精煉方法,其中在上述預處理精煉爐中進行鐵水的脫矽處理,其次,進行使鐵水及脫矽處理後的爐渣的一部分殘留在上述預處理精煉爐內的中間排渣,繼而,對殘留在上述預處理精煉爐內的脫矽處理後的鐵水添加CaO系助熔劑並且供給氧氣來進行鐵水的脫磷處理。 [5] The method for refining molten iron according to any one of the above [1], wherein the pretreatment refining furnace performs a demineralization treatment of molten iron, and secondly, the molten iron and the dislocation are performed. A part of the treated slag remains in the middle of the pretreatment refining furnace, and then a CaO-based flux is added to the dehydrated molten iron remaining in the pretreatment refining furnace, and oxygen is supplied to carry out the molten iron. Dephosphorization treatment.
[6]如上述[5]記載的鐵水的精煉方法,其中在上述預處理精煉爐中進行鐵水的脫磷處理,在將該脫磷處理後的鐵水自預處理精煉爐湧出之後,維持使脫磷處理後的爐渣殘留在爐內的狀態而將接下來填充的鐵水裝入至上述預處理精煉爐中,對該鐵水進行脫矽處理,其次,進行使鐵水及脫矽處理後的爐渣的一部分殘留在上述預處理精煉爐內的中間排渣,繼而,對殘留在上述預處理精 煉爐內的脫矽處理後的鐵水添加CaO系助熔劑並且供給氧氣而進行鐵水的脫磷處理。 [6] The method for refining molten iron according to the above [5], wherein the dephosphorization treatment of the molten iron is performed in the pretreatment refining furnace, and after the dephosphorization-treated molten iron is poured out from the pretreatment refining furnace, The slag after the dephosphorization treatment is left in the furnace, and the molten iron to be filled next is charged into the pretreatment refining furnace, the molten iron is subjected to a deodorization treatment, and secondly, the molten iron and the dislocation are performed. A part of the treated slag remains in the middle of the pretreatment refining furnace, and then remains in the pretreatment The molten iron after the deodorization treatment in the refining furnace is added with a CaO-based flux and supplied with oxygen to carry out dephosphorization treatment of the molten iron.
[7]如上述[1]至上述[6]中任一項記載的鐵水的精煉方法,其中上述預處理精煉爐中的預處理為脫磷處理,且經脫磷處理的鐵水的磷濃度為0.030質量%以下。 [7] The method for refining molten iron according to any one of the above [1] to [6] wherein the pretreatment in the pretreatment refining furnace is dephosphorization treatment, and phosphorus of the dephosphorization treated molten iron The concentration is 0.030% by mass or less.
[8]如上述[2]至上述[7]中任一項記載的鐵水的精煉方法,其中根據藉由上述爐渣收納搬送容器而裝入至預處理精煉爐中的爐渣的熱回收量,而決定預先裝入至上述爐渣收納搬送容器中的鐵渣的質量或在預處理前裝入至上述預處理精煉爐中的鐵渣的質量、與作為包含鐵礦石、鐵礦石的燒結礦、鐵銹皮(mill scale)、煉鐵粉(ironmaking dust)、磁選屑、鋼的切削屑的鐵源中的任1種或2種以上的自上述預處理精煉爐的爐上方投入至預處理精煉爐中的鐵源的質量的合計質量。 [8] The method for refining molten iron according to any one of the above [2], wherein the amount of heat recovered from the slag charged in the pretreatment refining furnace by the slag storage container is And determining the mass of the iron slag previously loaded into the slag storage and transport container or the mass of the iron slag charged into the pretreatment refining furnace before the pretreatment, and the sinter containing iron ore or iron ore Any one or two or more kinds of iron sources of mill scale, ironmaking dust, magnetic cuttings, and steel chips are fed from the top of the pretreatment refining furnace to the pretreatment refining The total mass of the iron source in the furnace.
本發明中,使殘留在脫碳精煉爐內的脫碳爐渣自積層的鐵渣上維持熔融狀態流下而使上述爐渣的至少一部分凝固,其後,在預處理精煉爐中的鐵水的預處理中,將至少一部分凝固的上述爐渣與上述鐵渣一同維持高溫而使用。藉此,可在預處理精煉爐中的鐵水的預處理中最大限度地利用鐵水的脫碳精煉中所生成的熔融爐渣的顯熱,從而可實現增加鐵渣等鐵源的調配量。又,在脫碳精煉中所生成的爐渣,在預處理中作為爐渣鹼度的調整劑及脫磷精煉劑發揮功能,因此在預處理精煉爐中的脫矽處理中, 爐渣鹼度的調整劑的單位消耗量(specific consumption)減少,在脫磷處理中脫磷精煉劑的單位消耗量減少。又,殘留在脫碳精煉爐內的鋼水或該鋼水凝固而成的凝固鐵,與脫碳爐渣一同裝入至預處理精煉爐中,因此從預處理精煉爐湧出的鐵水的產率提高。 In the present invention, the decarburization slag remaining in the decarburization refining furnace is maintained in a molten state from the iron slag of the buildup layer to cause at least a part of the slag to be solidified, and thereafter, the pretreatment of the molten iron in the pretreatment refining furnace Among them, at least a part of the solidified slag is used together with the iron slag to maintain a high temperature. Thereby, the sensible heat of the molten slag generated in the decarburization refining of the molten iron can be utilized to the utmost in the pretreatment of the molten iron in the pretreatment refining furnace, thereby increasing the amount of iron source such as iron slag. Further, the slag produced in the decarburization refining functions as a slag basicity adjuster and a dephosphorization refining agent in the pretreatment, and therefore, in the dislocation treatment in the pretreatment refining furnace, The specific consumption of the slag basicity adjuster is reduced, and the unit consumption of the dephosphorization refining agent is reduced in the dephosphorization treatment. Further, the molten steel remaining in the decarburization refining furnace or the solidified iron obtained by solidifying the molten steel is charged into the pretreatment refining furnace together with the decarburization slag, so the yield of molten iron ejected from the pretreatment refining furnace improve.
1‧‧‧預處理步驟 1‧‧‧Pretreatment steps
2‧‧‧低磷鐵水 2‧‧‧Low-phosphorus molten iron
2'‧‧‧脫矽鐵水 2'‧‧‧Destroyed hot metal
3‧‧‧脫碳精煉爐 3‧‧‧Decarbonization refining furnace
4‧‧‧脫碳精煉步驟 4‧‧‧Decarbonization refining steps
5‧‧‧鋼水 5‧‧‧Steel
6‧‧‧熔融爐渣(脫碳爐渣) 6‧‧‧Fusing slag (decarburization slag)
7‧‧‧鋼包 7‧‧‧Ladle
8‧‧‧殘留鋼水 8‧‧‧Residual molten steel
9‧‧‧殘留熔融爐渣 9‧‧‧Residual molten slag
10‧‧‧爐渣收納搬送容器 10‧‧‧Slag storage container
10a‧‧‧耐火物層 10a‧‧‧ refractory layer
11‧‧‧爐渣收納搬送容器 11‧‧‧Slag storage container
12‧‧‧鐵渣 12‧‧‧ iron slag
13‧‧‧含金屬爐渣 13‧‧‧Metal slag
14‧‧‧預處理精煉爐 14‧‧‧Pretreatment refining furnace
15‧‧‧鐵水 15‧‧‧ molten iron
16‧‧‧所有熔融金屬 16‧‧‧All molten metal
圖1是本發明的鐵水的精煉方法的處理流程的概略圖。 Fig. 1 is a schematic view showing a treatment flow of a molten iron refining method of the present invention.
以下,參照隨附圖式對本發明進行具體說明。圖1是本發明的鐵水的精煉方法的處理流程的概略圖。 Hereinafter, the present invention will be specifically described with reference to the accompanying drawings. Fig. 1 is a schematic view showing a treatment flow of a molten iron refining method of the present invention.
將在鐵水的預處理步驟1中進行脫磷處理而使磷濃度降低的低磷鐵水2、或在鐵水的預處理步驟1中進行脫矽處理而使矽濃度降低的脫矽鐵水2'裝入至作為轉爐型精煉爐的脫碳精煉爐3,進而裝入生石灰(CaO)或白雲石(dolomite)(CaO-MgO)作為助熔劑,使用頂噴氧(top-blowing oxygen)或底噴氧對低磷鐵水2或脫矽鐵水2'實施脫碳精煉(脫碳精煉步驟4)。此處,脫磷處理如上所述,包含對未進行脫矽處理的鐵水進行脫矽處理且進行脫磷處理的情形、及對已進行脫矽處理的鐵水進行脫磷處理的情形這兩者。又,生石灰、白雲石、石灰石(CaCO3)等,自含有CaO作為主成分的方面而言稱作CaO系助熔劑。 The low-phosphorus iron water 2 which is subjected to the dephosphorization treatment in the pretreatment step 1 of the molten iron to reduce the phosphorus concentration, or the deodorized molten iron which is subjected to the deodorization treatment in the pretreatment step 1 of the molten iron to reduce the concentration of rhodium 2' is charged to the decarburization refining furnace 3 as a converter type refining furnace, and further charged with quicklime (CaO) or dolomite (CaO-MgO) as a flux, using top-blowing oxygen or The bottom spray oxygen performs decarburization refining on the low phosphorus iron water 2 or the deferred iron water 2' (decarburization refining step 4). Here, as described above, the dephosphorization treatment includes a case where the deionized treatment is performed on the molten iron which has not been subjected to the deodorization treatment, and the dephosphorization treatment is performed, and the dephosphorization treatment is performed on the molten iron which has been subjected to the deodorization treatment. By. Further, lime, dolomite, limestone (CaCO 3) and the like, from the aspect of terms containing CaO as a main component called CaO-based flux.
低磷鐵水2或脫矽鐵水2'藉由脫碳精煉而精煉為鋼水5。又,藉由脫碳精煉,利用生石灰及白雲石、與鐵水中所含有的 矽的氧化物(SiO2)而生成鹼度((質量%CaO)/(質量%SiO2))為3~5左右的熔融爐渣(脫碳爐渣)6。 The low-phosphorus molten iron 2 or the deferred molten iron 2' is refined into molten steel 5 by decarburization refining. Further, by decarburization and refining, alkalinity ((% by mass CaO) / (% by mass SiO 2 )) is 3 to 5 by using quicklime, dolomite, and cerium oxide (SiO 2 ) contained in molten iron. Left and right molten slag (decarburization slag) 6.
脫碳精煉結束後,將熔煉的鋼水5經由設置在脫碳精煉爐3的側壁部的湧出口(未圖示)而自脫碳精煉爐3湧出至鋼包7。此時,以極力使在脫碳精煉中所生成的熔融爐渣6殘留在脫碳精煉爐3中的方式進行控制而湧出。然而,熔融爐渣6的一部分在湧出末期混入至鋼水5中並流出至鋼包7中。湧出至鋼包7中的鋼水5雖未圖示,但視需要而經過下一步驟的二次精煉後搬送至連續鑄造步驟,將鋼水5連續鑄造為鑄片。 After the completion of the decarburization refining, the molten steel 5 is poured from the decarburization refining furnace 3 to the ladle 7 through a gush (not shown) provided in the side wall portion of the decarburization refining furnace 3. At this time, the molten slag 6 generated in the decarburization refining is controlled so as to remain in the decarburization refining furnace 3 as much as possible. However, a part of the molten slag 6 is mixed into the molten steel 5 at the end of the discharge and flows out into the ladle 7. The molten steel 5 that has flowed into the ladle 7 is not shown, but is subjected to secondary refining in the next step as needed, and then transferred to a continuous casting step, and the molten steel 5 is continuously cast into a cast piece.
湧出結束後,使脫碳精煉爐3向湧出側的相反側傾斜(tilt),而將殘留在脫碳精煉爐內的殘留熔融爐渣9自脫碳精煉爐3的爐口直接排出至爐渣收納搬送容器10或爐渣收納搬送容器11。爐渣收納搬送容器10在內表面側佈設有耐火物層10a且具有突出的寬幅的灌注口。另一方面,爐渣收納搬送容器11具有突出的寬幅的灌注口,但不具有耐火物層,例如為包含鑄鐵、鑄鋼等的金屬製造的,在其內部預先裝入有鐵渣12。進而,此時,殘留在脫碳精煉爐3中的少量的殘留鋼水8,亦與殘留熔融爐渣9一同全部排出至爐渣收納搬送容器10或爐渣收納搬送容器11。 After the completion of the gushing, the decarburization refining furnace 3 is tilted to the opposite side of the gushing side, and the residual molten slag 9 remaining in the decarburization refining furnace is directly discharged from the furnace opening of the decarburization refining furnace 3 to the slag storage and transportation. The container 10 or the slag accommodates the transfer container 11. The slag storage conveyance container 10 is provided with a refractory layer 10a on the inner surface side and has a protruding wide opening. On the other hand, the slag storage conveyance container 11 has a protruding wide infusion port, but does not have a refractory layer, and is made of, for example, a metal including cast iron or cast steel, and the iron slag 12 is preliminarily incorporated therein. Furthermore, at this time, a small amount of residual molten steel 8 remaining in the decarburization refining furnace 3 is also discharged to the slag storage conveyance container 10 or the slag storage conveyance container 11 together with the residual molten slag 9.
使殘留熔融爐渣9排出至預先裝入有鐵渣12的爐渣收納搬送容器11,並使該殘留熔融爐渣9自積層在爐渣收納搬送容器內的鐵渣上維持熔融狀態而流下,藉此殘留熔融爐渣9的至少一部分凝固。 The residual molten slag 9 is discharged to the slag storage and transport container 11 in which the iron slag 12 is preliminarily loaded, and the residual molten slag 9 is kept in a molten state from the iron slag which is deposited in the slag storage and transport container, thereby remaining molten. At least a portion of the slag 9 solidifies.
再者,爐渣收納搬送容器10為用以將殘留熔融爐渣9維持熔融狀態搬送至預處理精煉爐14中的容器,在內表面側佈設有耐火物層10a,但並非必須佈設有耐火物層10a。即便爐渣收納搬送容器10為包含鑄鐵等的金屬製造的,收納在爐渣收納搬送容器10中的殘留熔融爐渣9亦可不立即凝固而是將殘留熔融爐渣9維持熔融狀態而裝入至預處理精煉爐14中。在佈設有耐火物層10a的情形時,在接收殘留熔融爐渣9之後可在短時間內將殘留熔融爐渣9裝入至預處理精煉爐14中,此時可享受熱損耗減少的效果,但保持時間變長,在殘留熔融爐渣9的一部分或殘留鋼水8凝固而附著在容器內表面上的情形時難以剝離,反而會使作業變得混亂。該情形時,較佳為不佈設耐火物層10a。 In addition, the slag storage conveyance container 10 is a container for conveying the residual molten slag 9 to the pretreatment refining furnace 14 in a molten state, and the refractory layer 10a is provided on the inner surface side, but it is not necessary to provide the refractory layer 10a. . Even if the slag storage and conveyance container 10 is made of a metal containing cast iron or the like, the residual molten slag 9 accommodated in the slag storage and conveyance container 10 may be solidified without being solidified immediately, and may be charged to the pretreatment refining furnace while maintaining the molten slag 9 in a molten state. 14 in. In the case where the refractory layer 10a is provided, the residual molten slag 9 can be charged into the pretreatment refining furnace 14 in a short time after receiving the residual molten slag 9, and the heat loss reduction effect can be enjoyed at this time, but it is maintained. When the time is long, it is difficult to peel off when a part of the residual molten slag 9 or the residual molten steel 8 solidifies and adheres to the inner surface of the container, and the work is disturbed. In this case, it is preferable not to arrange the refractory layer 10a.
其次,將自脫碳精煉爐3排出至爐渣收納搬送容器10中的殘留鋼水8及殘留熔融爐渣9裝入至預先裝入有鐵渣12的轉爐型精煉爐即預處理精煉爐14。在對爐渣收納搬送容器10佈設有耐火物層10a的情形時,保溫性高,殘留鋼水8及殘留熔融爐渣9即便在爐渣收納搬送容器10中保持5分鐘~30分鐘左右亦幾乎不會凝固。 Then, the residual molten steel 8 and the residual molten slag 9 discharged from the decarburization refining furnace 3 to the slag storage and conveyance container 10 are placed in a pretreatment refining furnace 14 which is a converter-type refining furnace in which the iron slag 12 is previously loaded. When the refractory layer 10a is placed on the slag storage and transport container 10, the heat retaining property is high, and the residual molten steel 8 and the residual molten slag 9 are hardly solidified even if they are held in the slag storage and transport container 10 for about 5 minutes to 30 minutes. .
其後,將鐵水15裝入至預處理精煉爐14中,對預處理精煉爐內的所有熔融金屬16(殘留鋼水8+鐵水15+熔融的鐵渣12)實施脫矽處理或脫磷處理。脫矽處理中,裝入至預處理精煉爐14中的殘留熔融爐渣9作為爐渣鹼度調整劑發揮功能,脫磷處理中,裝入至預處理精煉爐14中的殘留熔融爐渣9作為脫磷精煉劑發揮 功能。此處,脫磷精煉劑是指用以將藉由脫磷反應而生成的磷氧化物(P2O5)作為3CaO.P2O5來固定在爐渣中的精煉劑。 Thereafter, the molten iron 15 is charged into the pretreatment refining furnace 14, and all the molten metal 16 (residual molten steel 8 + molten iron 15 + molten iron slag 12) in the pretreatment refining furnace is subjected to deodorization treatment or removal. Phosphorus treatment. In the untwisting treatment, the residual molten slag 9 charged into the pretreatment refining furnace 14 functions as a slag basicity adjuster, and the residual molten slag 9 charged into the pretreatment refining furnace 14 is used as dephosphorization in the dephosphorization treatment. The refining agent functions. Here, the dephosphorization refining agent refers to the phosphorus oxide (P 2 O 5 ) formed by the dephosphorization reaction as 3CaO. P 2 O 5 to fix the refining agent in the slag.
至少使殘留熔融爐渣9的一部分維持熔融狀態自積層在預處理精煉爐內的鐵渣12的上方流下,藉此殘留熔融爐渣9的至少一部分以附著在鐵渣12上或浸入鐵渣12的間隙的方式凝固。又,使較殘留熔融爐渣9為更高熔點且更高熱導率的殘留鋼水8,與殘留熔融爐渣9同時自鐵渣12上流下而成為大致凝固狀態。 At least a part of the residual molten slag 9 is maintained in a molten state, and the self-assembled layer flows down the iron slag 12 in the pre-treatment refining furnace, whereby at least a part of the molten slag 9 remains to adhere to the iron slag 12 or to immerse in the gap of the iron slag 12. The way to solidify. Further, the residual molten steel 8 having a higher melting point and higher thermal conductivity than the residual molten slag 9 flows down from the iron slag 12 together with the residual molten slag 9 to be substantially solidified.
如此般與鐵渣12進行熱交換之後的殘留熔融爐渣9及殘留鋼水8,液相率降低而成為與鐵水的反應性降低的狀態,從而可防止因與裝入至預處理精煉爐中的鐵水15的急遽反應而妨礙作業。若與該方法相反地,將排出至爐渣收納搬送容器10中的殘留鋼水8及殘留熔融爐渣9裝入至進行出鐵及排渣之後的空的預處理精煉爐14,其後,裝入鐵渣12,其次裝入鐵水15,則殘留鋼水8及殘留熔融爐渣9與鐵渣12的熱交換不充分,維持與鐵水的反應性高的狀態而有在裝入鐵水15時因噴出鐵水或火焰而妨礙作業的情形,因而不理想。 The residual molten slag 9 and the residual molten steel 8 after heat exchange with the iron slag 12 have a lower liquid phase ratio and a lower reactivity with molten iron, thereby preventing the loading into the pretreatment refining furnace. The rapid reaction of the molten iron 15 hinders the work. In contrast to this method, the residual molten steel 8 and the residual molten slag 9 discharged into the slag storage and conveyance container 10 are loaded into the empty pretreatment refining furnace 14 after the iron discharge and the slag discharge, and then loaded. When the iron slag 12 is placed in the molten iron 15 in the second place, the residual molten steel 8 and the residual molten slag 9 are insufficiently exchanged with the iron slag 12, and the reactivity with the molten iron is maintained high. It is not desirable because the molten iron or the flame is ejected to hinder the work.
進而,如上述般凝固的殘留熔融爐渣9不形成大塊的凝固爐渣,而是以細分化的狀態固化,因此即便在相對低溫的鐵水的預處理中亦不會妨礙渣化,可作為精煉劑有效地發揮功能。 Further, since the residual molten slag 9 solidified as described above does not form a large solidified slag, but is solidified in a subdivided state, it does not interfere with slag formation even in the pretreatment of molten iron at a relatively low temperature, and can be used as a refining. The agent functions effectively.
自脫碳精煉爐3排出至預先裝入有鐵渣12的金屬製的爐渣收納搬送容器11中的殘留鋼水8及殘留熔融爐渣9,亦同樣地與鐵渣12一同裝入至預處理精煉爐14。然而,排出至金屬製的 爐渣收納搬送容器11中的殘留鋼水8及殘留熔融爐渣9,自預先裝入至爐渣收納搬送容器11中的鐵渣12上流下,殘留鋼水8及殘留熔融爐渣9的顯熱用於鐵渣12的預熱。藉此,殘留鋼水8及殘留熔融爐渣9的至少一部分凝固、固化,而成為凝固鐵和固化的爐渣混合而成的含金屬爐渣13(metal-containing slag)。即,殘留鋼水8及殘留熔融爐渣9,成為與鐵水的反應性降低的含金屬爐渣13,因此即便在剛裝入至預處理精煉爐14中之後便進而裝入鐵水15,亦可安全地進行作業。又,含金屬爐渣13在與鐵渣12一同裝入至預處理精煉爐14時藉由下落能量而細分化,因此於在預處理精煉中促進渣化的方面而言該方法亦有利。 The residual molten steel 8 and the residual molten slag 9 discharged from the decarburization refining furnace 3 to the metal slag storage and transport container 11 in which the iron slag 12 is preliminarily loaded are similarly loaded with the iron slag 12 to the pretreatment refining. Furnace 14. However, it is discharged to metal The residual molten steel 8 and the residual molten slag 9 in the slag storage and transport container 11 are discharged from the iron slag 12 previously loaded into the slag storage and transport container 11, and the sensible heat of the molten steel 8 and the residual molten slag 9 is used for iron. Preheating of the slag 12. Thereby, at least a part of the residual molten steel 8 and the residual molten slag 9 are solidified and solidified, and the metal-containing slag 13 is obtained by mixing the solidified iron and the solidified slag. In other words, the residual molten steel 8 and the residual molten slag 9 become the metal-containing slag 13 having reduced reactivity with molten iron. Therefore, even after being charged into the pretreatment refining furnace 14, the molten iron 15 can be further charged. Work safely. Further, since the metal-containing slag 13 is subdivided by the falling energy when it is charged together with the iron slag 12 to the pretreatment refining furnace 14, the method is also advantageous in terms of promoting slag formation in the pretreatment refining.
預先裝入至金屬製的爐渣收納搬送容器11的鐵渣12的質量,較佳為從脫碳精煉爐3排出的殘留鋼水8及殘留熔融爐渣9的合計質量的1.5倍~4.5倍,更佳為2倍~3倍。若預先裝入的鐵渣量少,則殘留鋼水8及殘留熔融爐渣9的凝固、固化不充分,在將鐵水15裝入至預處理精煉爐14中時,因急遽地產生CO氣體而導致鐵水或爐渣噴出的危險增大。又,亦有合計的鐵源使用量減少而無法有效地利用殘留熔融爐渣9的顯熱,或因裝入追加的鐵渣而延長作業時間從而導致生產性降低的問題。 The mass of the iron slag 12 previously charged in the metal slag storage and transport container 11 is preferably 1.5 times to 4.5 times the total mass of the residual molten steel 8 and the residual molten slag 9 discharged from the decarburization refining furnace 3, and more preferably The best is 2 to 3 times. When the amount of the iron slag to be charged is small, solidification and solidification of the residual molten steel 8 and the residual molten slag 9 are insufficient, and when the molten iron 15 is charged into the pretreatment refining furnace 14, the CO gas is rapidly generated. The risk of causing molten iron or slag to spurt increases. In addition, there is a problem in that the total amount of iron source used is reduced, and the sensible heat of the residual molten slag 9 cannot be effectively utilized, or the operation time is prolonged by the addition of the additional iron slag, resulting in a decrease in productivity.
另一方面,若預先裝入的鐵渣量多,則產生用於升溫等的精煉負荷增大而導致成本增大或精煉時間延長的問題,又,亦產生在預處理中無法將所有鐵渣12熔解的問題。又,亦產生必需容量大的爐渣收納搬送容器11的問題。 On the other hand, if the amount of iron slag to be charged in advance is large, there is a problem that the refining load for increasing the temperature or the like increases, which causes an increase in cost or an increase in refining time, and also causes that all the iron slag cannot be removed in the pretreatment. 12 melting problems. Further, there is also a problem that the slag having a large capacity is required to accommodate the transfer container 11.
再者,裝入至爐渣收納搬送容器11中的鐵渣12的量,較佳設為裝入至預處理精煉爐14中的鐵渣的總量。藉此,可兼顧鐵渣裝入與爐渣裝入,可防止裝入次數增加而使作業時間延長,從而生產性降低,並且可將脫碳熔煉(smelting)爐3的爐渣維持熱狀態而重複利用於預處理精煉爐14。 In addition, the amount of the iron slag 12 charged in the slag storage conveyance container 11 is preferably the total amount of the iron slag charged in the pretreatment refining furnace 14. Thereby, both the iron slag charging and the slag charging can be taken into consideration, and the increase in the number of times of loading can be prevented, the working time can be prolonged, the productivity can be lowered, and the slag of the demelting smelting furnace 3 can be maintained in a hot state and reused. The pretreatment furnace 14 is pretreated.
如此,殘留鋼水8及殘留熔融爐渣9凝固、固化而成為含金屬爐渣13。其顯熱被回收至預處理精煉爐14中所裝入的鐵渣12中,而作為用於下一步驟的預處理精煉爐14的預處理中的鐵渣12的熔解的熱發揮功能。再者,即便稱為凝固、固化,含金屬爐渣13亦為大約300℃以上的高溫,含金屬爐渣13的顯熱亦在預處理時被回收。 In this manner, the residual molten steel 8 and the residual molten slag 9 are solidified and solidified to become the metal-containing slag 13 . The sensible heat is recovered into the iron slag 12 charged in the pretreatment refining furnace 14, and functions as the heat of melting of the iron slag 12 in the pretreatment of the pretreatment refining furnace 14 for the next step. Further, even if it is called solidification or solidification, the metal-containing slag 13 is also at a high temperature of about 300 ° C or higher, and the sensible heat of the metal-containing slag 13 is also recovered at the time of pretreatment.
其後,將鐵水15裝入至預處理精煉爐14中,對預處理精煉爐內的所有熔融金屬16(含金屬爐渣13的凝固鐵成分+鐵水15)實施預處理。在該預處理中,作為含金屬爐渣13即裝入的殘留熔融爐渣9固化而成者,接收鐵水15的熱而渣化,在預處理為脫矽處理的情形時作為爐渣鹼度調整劑發揮功能,而在預處理為脫磷處理的情形時作為脫磷精煉劑發揮功能。 Thereafter, the molten iron 15 is charged into the pretreatment refining furnace 14, and all the molten metal 16 (the solidified iron component containing the metal slag 13 + the molten iron 15) in the pretreatment refining furnace is pretreated. In the pretreatment, the residual molten slag 9 charged as the metal-containing slag 13 is solidified, and the heat of the molten iron 15 is received and slag is formed, and when the pretreatment is a de-slipping treatment, it is used as a slag basicity adjuster. It functions as a dephosphorization refining agent when the pretreatment is dephosphorization treatment.
預處理精煉爐14中的預處理以如下方式進行,即一面自爐底的底噴風口將氮氣等作為攪拌用氣體噴入至所有熔融金屬16,一面自頂噴噴管(lance)將氧氣頂噴至所有熔融金屬16。在預處理為脫矽處理的情形時,鐵水中的矽被頂噴供給的氧氣氧化(脫矽反應:Si+O2→SiO2)而成為矽氧化物(SiO2)。該矽氧化物 與殘留熔融爐渣9或含金屬爐渣13中所含有的CaO反應而在爐內形成爐渣。在預處理為脫磷處理的情形時,鐵水中的磷被頂噴供給的氧氣氧化(脫磷反應:2P+5/2O2→P2O5)而成為磷氧化物(P2O5)。該磷氧化物與裝入至爐內的殘留熔融爐渣9或含金屬爐渣13中所含有的作為脫磷精煉劑發揮功能的CaO鍵結而固定為3CaO.P2O5。 The pretreatment in the pretreatment refining furnace 14 is carried out by spraying nitrogen gas or the like as a stirring gas to all the molten metal 16 from the bottom blast port of the bottom of the furnace, and topping the oxygen gas from the top lance. Spray to all molten metal 16. In the case where the pretreatment is a dehalation treatment, the hydrazine in the molten iron is oxidized by the oxygen supplied from the top spray (depuration reaction: Si + O 2 → SiO 2 ) to become cerium oxide (SiO 2 ). The niobium oxide reacts with the residual molten slag 9 or CaO contained in the metal-containing slag 13 to form slag in the furnace. In the case where the pretreatment is dephosphorization treatment, the phosphorus in the molten iron is oxidized by the oxygen supplied from the top spray (dephosphorization reaction: 2P+5/2O 2 →P 2 O 5 ) to become phosphorus oxide (P 2 O 5 ). . The phosphorus oxide is fixed to 3CaO by a CaO bond functioning as a dephosphorization refining agent contained in the residual molten slag 9 or the metal-containing slag 13 charged in the furnace. P 2 O 5 .
在對未進行脫矽處理的鐵水進行脫磷處理時,在脫磷處理的初期產生上述的脫矽反應,在鐵水中的矽濃度降低至低於約0.10質量%之後,產生上述的脫磷反應。該情形時,亦將主要產生脫矽反應的期間稱作脫矽期,將後半部分的產生脫磷反應的期間稱作脫磷期。在爐內爐渣的鹼度低的情形時並不會形成3CaO.P2O5,因此,在僅利用裝入的殘留熔融爐渣9或含金屬爐渣13而無法確保爐內生成的爐渣的鹼度為2.0以上的情形時,在使磷濃度降低的方面而言,較佳為添加生石灰(CaO)等作為脫磷精煉劑。 When the demineralized treatment is performed on the molten iron which has not been subjected to the deodorization treatment, the above-described depurination reaction occurs in the initial stage of the dephosphorization treatment, and after the concentration of rhodium in the molten iron is lowered to less than about 0.10% by mass, the above dephosphorization is produced. reaction. In this case, the period in which the depurination reaction mainly occurs is also referred to as the deuteration period, and the period in which the dephosphorization reaction occurs in the latter half is referred to as the dephosphorization period. When the alkalinity of the slag in the furnace is low, 3CaO is not formed. When P 2 O 5 is used , it is not possible to ensure that the alkalinity of the slag generated in the furnace is 2.0 or more when only the residual molten slag 9 or the metal-containing slag 13 is charged, and the phosphorus concentration is lowered. It is preferable to add quicklime (CaO) or the like as a dephosphorization refining agent.
在鐵水15的預處理步驟1中,在預處理為脫磷處理的情形時,較佳為使脫磷處理後的低磷鐵水2的磷濃度為0.030質量%以下,理想的是0.020質量%以下。若在脫碳精煉爐3中對該低磷鐵水2進行脫碳精煉,則生成的熔融爐渣6的磷濃度以P2O5換算濃度計而降低至1.5質量%左右以下的低濃度。在將該低磷濃度的熔融爐渣6用作下一預處理精煉爐14中的脫磷用精煉劑的一部分的情形時,爐渣中磷濃度的上升被抑制,從而可進行更有效的 脫磷處理。 In the pretreatment step 1 of the molten iron 15, in the case where the pretreatment is dephosphorization treatment, it is preferred that the phosphorus concentration of the low-phosphorus molten iron 2 after the dephosphorization treatment is 0.030% by mass or less, preferably 0.020% by mass. %the following. When the low-phosphorus molten iron 2 is subjected to decarburization and refining in the decarburization refining furnace 3, the phosphorus concentration of the produced molten slag 6 is lowered to a low concentration of about 1.5% by mass or less in terms of P 2 O 5 -based concentration. When the low-phosphorus concentration molten slag 6 is used as a part of the dephosphorization refining agent in the next pretreatment refining furnace 14, the increase in the phosphorus concentration in the slag is suppressed, so that more efficient dephosphorization treatment can be performed. .
本發明中,向預處理精煉爐14中裝入熔融狀態的殘留鋼水8及殘留熔融爐渣9、或利用殘留鋼水8及殘留熔融爐渣9預熱的鐵渣12及含金屬爐渣13,因此,與現有的預處理相比,預處理中的入熱量增加與該等裝入量相當的量。在未多裝入鐵渣等的情形時,預處理結束時的鐵水溫度上升與入熱量的增加量相當的量,但在脫磷處理的情形時,若為使脫磷精煉劑進行渣化的溫度範圍內,則鐵水溫度越低越促進脫磷反應。因此,較佳為將預先裝入至預處理精煉爐14中的鐵渣的質量、或裝入至爐渣收納搬送容器11中的鐵渣的質量、及自爐上方的漏斗(hopper)投入的磁選屑(magnetically separated slag-containing iron lump)等鐵源的使用量,增加與熔融狀態的殘留鋼水8及殘留熔融爐渣9等所引起的入熱量的增加量相當的量。在脫矽處理的情形時,自提高生產性的觀點考慮,亦較佳為將鐵渣等的使用量增加與殘留鋼水8及殘留熔融爐渣9等所引起的入熱量的增加量相當的量。 In the present invention, the pre-refining furnace 14 is filled with the residual molten steel 8 and the residual molten slag 9 in the molten state, or the iron slag 12 and the metal-containing slag 13 which are preheated by the residual molten steel 8 and the residual molten slag 9. Compared with the existing pretreatment, the amount of heat input in the pretreatment is increased by an amount equivalent to the amount of the charge. In the case where iron slag or the like is not added, the temperature of the molten iron at the end of the pretreatment is increased by an amount corresponding to the amount of increase in the amount of heat input, but in the case of dephosphorization treatment, if the dephosphorization refining agent is slagized Within the temperature range, the lower the temperature of the molten iron, the more the dephosphorization reaction is promoted. Therefore, it is preferable that the mass of the iron slag previously charged into the pretreatment refining furnace 14 or the mass of the iron slag charged in the slag storage and transport container 11 and the magnetic hopper input from the hopper above the furnace are preferably selected. The amount of the iron source used, such as the magnetically separated slag-containing iron lump, is increased by an amount corresponding to the amount of increase in the amount of heat input caused by the residual molten steel 8 and the residual molten slag 9 in the molten state. In the case of the dislocation treatment, it is also preferable to increase the amount of iron slag or the like by an amount corresponding to the increase in the amount of heat input caused by the residual molten steel 8 and the residual molten slag 9 or the like from the viewpoint of improving the productivity. .
本發明者等自調查結果確認出,即便針對每1噸利用上述方法再循環至預處理精煉爐14中的殘留鋼水8及殘留熔融爐渣9的合計量而多裝入1.5噸左右以下的鐵渣或磁選屑等鐵源,在預處理中多裝入的量亦包含在內而全部熔解。 As a result of the investigation, the inventors of the present invention have confirmed that iron is added in an amount of about 1.5 tons or less per 1 ton of the total amount of the residual molten steel 8 and the residual molten slag 9 which are recycled to the pretreatment refining furnace 14 by the above-described method. The iron source such as slag or magnetic separator is also included in the pretreatment and is completely melted.
因此,較佳為根據藉由爐渣收納搬送容器10、爐渣收納搬送容器11而再循環至預處理精煉爐14中的殘留熔融爐渣9(固化後的殘留熔融爐渣9)的熱回收量,而決定以下合計質量:預先 裝入至爐渣收納搬送容器11中的鐵渣12的質量、或預先裝入至預處理精煉爐14中的鐵渣12的質量、與自爐上方的漏斗投入的磁選屑等鐵源的質量的合計質量。作為自爐上方的漏斗投入的鐵源,除磁選屑以外,還可使用鐵礦石、鐵礦石的燒結礦、鐵銹皮、煉鐵粉、鋼的切削屑(steel cutting chip)等。 Therefore, it is preferable to determine the amount of heat recovery of the residual molten slag 9 (residual molten slag 9 after curing) which is recycled to the pretreatment refining furnace 14 by the slag storage container 10 and the slag storage container 11 Total quality below: in advance The mass of the iron slag 12 charged in the slag storage and transport container 11 or the mass of the iron slag 12 previously charged into the pretreatment refining furnace 14 and the mass of the iron source such as the magnetic swarf input from the funnel above the furnace Total quality. As the iron source to be fed from the funnel above the furnace, in addition to the magnetic selection, iron ore, iron ore sintered ore, iron scale, iron powder, steel cutting chip, or the like can be used.
藉由爐渣收納搬送容器10、爐渣收納搬送容器11而將殘留鋼水8及殘留熔融爐渣9裝入至預處理精煉爐14中所產生的熱回收量,以「鋼水(殘留鋼水8)比熱×鋼水質量×鋼水溫度+爐渣(殘留熔融爐渣9)比熱×熔融爐渣質量×爐渣溫度」來表示。在實際作業中,亦可簡化為熱回收量=「(殘留熔融爐渣9與殘留鋼水8的平均比熱)×(殘留熔融爐渣9與殘留鋼水8的合計質量)×(殘留熔融爐渣9與殘留鋼水8與平均溫度)」。 The amount of heat recovered by charging the residual molten steel 8 and the residual molten slag 9 into the pretreatment refining furnace 14 by the slag storage conveyance container 10 and the slag storage conveyance container 11 is "steel water (residual molten steel 8)" Specific heat × molten steel mass × molten steel temperature + slag (residual molten slag 9) specific heat × molten slag quality × slag temperature). In actual work, it can be simplified as heat recovery amount = "(average specific heat of residual molten slag 9 and residual molten steel 8) × (total mass of residual molten slag 9 and residual molten steel 8) × (residual molten slag 9 and Residual molten steel 8 and average temperature)".
又,實際作業中,即便使預先裝入至預處理精煉爐14中的鐵渣的質量、或藉由爐渣收納搬送容器11而裝入至預處理精煉爐14中的鐵渣的質量,為較根據經驗而求出的可熔解質量少的值或固定值,並且根據藉由爐渣收納搬送容器10、爐渣收納搬送容器11而裝入至預處理精煉爐14中的殘留鋼水8(包含凝固的殘留鋼水8)與殘留熔融爐渣9(固化後的殘留熔融爐渣9)的合計質量,而決定作為鐵礦石、鐵礦石的燒結礦、鐵銹皮、煉鐵粉、磁選屑、鋼的切削屑中的任1種或2種以上的自爐上方投入至預處理精煉爐14的鐵源的合計投入質量,亦可獲得本發明的效果。 In the actual operation, the mass of the iron slag previously charged in the pretreatment refining furnace 14 or the mass of the iron slag charged in the pretreatment refining furnace 14 by the slag storage and transportation container 11 is The residual molten steel 8 (including solidified in the pretreatment refining furnace 14) which is obtained by the slag storage and transport container 11 and the slag storage transport container 11 is obtained from the slag storage transport container 10 and the slag storage transport container 11 The total amount of residual molten steel 8) and residual molten slag 9 (residual molten slag 9 after solidification) is determined as the cut of iron ore, iron ore, sinter, iron smelting powder, magnetic separator, and steel. The effect of the present invention can also be obtained by the total input quality of any one or two or more kinds of irons which are supplied to the pretreatment refining furnace 14 from above the furnace.
本發明中,預處理精煉爐14中的預處理亦可為如下預 處理中的任一者,該預處理為:(1)包含脫矽處理、排渣的步驟的預處理;(2)包含脫矽鐵水的脫磷處理、排渣的步驟的預處理;(3)包含脫矽、脫磷處理、排渣的步驟的預處理;(4)包含脫矽、脫磷處理、爐內的爐渣殘留、接下來填充的鐵水裝入的步驟的預處理;及(5)包含脫矽處理、中間排渣、脫磷處理、爐內的爐渣殘留、接下來填充的鐵水裝入的步驟的預處理。又,即便為任一預處理,均可獲得同樣的熱效果。又,藉由自殘留熔融爐渣9(固化後的殘留熔融爐渣9)的回收熱,即便在短時間的脫矽處理期間,亦可促進爐渣渣化,因此可防止自爐內的附著爐渣或殘留的爐渣復磷而進行有效的預處理。 In the present invention, the pretreatment in the pretreatment refining furnace 14 may also be as follows In any of the treatments, the pretreatment is: (1) a pretreatment comprising a step of deodorization treatment, slagging; (2) a pretreatment comprising a dephosphorization treatment of deferred molten iron and a step of slagging; 3) pretreatment comprising a step of decarburization, dephosphorization treatment, and slagging; (4) pretreatment comprising a step of decarburization, dephosphorization treatment, slag residue in the furnace, and subsequent filling of molten iron; and (5) Pretreatment including a step of disentrifling treatment, intermediate slag removal, dephosphorization treatment, slag remaining in the furnace, and subsequent charging of molten iron. Moreover, the same thermal effect can be obtained even for any pretreatment. In addition, by the heat of recovery from the residual molten slag 9 (the residual molten slag 9 after solidification), the slag can be promoted even during the short-term de-discharging treatment, thereby preventing the adhesion of slag or residue from the furnace. The slag is rephosphorized for effective pretreatment.
如以上所說明,根據本發明,可將在脫碳精煉爐3中的脫碳精煉中所生成的熔融爐渣6的顯熱及爐內殘留鋼水8的顯熱,最大限度地利用於預處理精煉爐14中的鐵水15的預處理,進而,在預處理精煉爐14中,爐渣鹼度調整劑或脫磷精煉劑的單位消耗量減少,且湧出產率進一步提高。 As described above, according to the present invention, the sensible heat of the molten slag 6 generated in the decarburization refining in the decarburization refining furnace 3 and the sensible heat of the molten steel 8 in the furnace can be utilized to the maximum extent for pretreatment. The pretreatment of the molten iron 15 in the refining furnace 14 further increases the unit consumption of the slag basicity adjuster or the dephosphorization refining agent in the pretreatment refining furnace 14, and the gushing yield is further improved.
以下,藉由實施例而更詳細地說明本發明。按照圖1所示的本發明的鐵水的精煉方法的處理流程進行以下試驗。在以下試驗中,作為預處理精煉爐14中的預處理,不實施脫矽處理而實施鐵水的脫磷處理(脫矽、脫磷處理)。 Hereinafter, the present invention will be described in more detail by way of examples. The following test was carried out in accordance with the treatment flow of the molten iron refining method of the present invention shown in Fig. 1. In the following test, as a pretreatment in the pretreatment refining furnace 14, dephosphorization treatment (depurination, dephosphorization treatment) of molten iron was carried out without performing deodorization treatment.
將磷濃度為0.020質量%的低磷鐵水2裝入至300噸容量的脫碳精煉爐3(轉爐)中,進而裝入生石灰與白雲石作為助熔 劑,一面自爐底的底噴風口噴入氬氣(Ar氣體)作為攪拌用氣體,一面自頂噴噴管供給氧氣而進行脫碳精煉。在脫碳精煉結束之後,將所獲得的鋼水5湧出至鋼包7中,湧出至鋼包7中的鋼水5視需要而經過下一步驟的二次精煉,並搬送至鑄造步驟來將鋼水5鑄造為鑄片。另一方面,在湧出操作結束後的脫碳精煉爐內,殘留有約7噸殘留熔融爐渣9與約2噸殘留鋼水8。 The low-phosphorus molten iron 2 having a phosphorus concentration of 0.020% by mass is charged into a 300-ton capacity decarburization refining furnace 3 (converter), and then the quicklime and dolomite are charged as a fluxing aid. The agent was sprayed with argon gas (Ar gas) as a stirring gas from the bottom air injection port of the furnace bottom, and decarburization refining was performed by supplying oxygen from the top nozzle. After the completion of the decarburization refining, the obtained molten steel 5 is poured out into the ladle 7, and the molten steel 5 which is poured into the ladle 7 is subjected to the secondary refining of the next step as needed, and is transferred to the casting step. The molten steel 5 is cast into a cast piece. On the other hand, about 7 tons of residual molten slag 9 and about 2 tons of residual molten steel 8 remain in the decarburization refining furnace after the completion of the gushing operation.
轉爐型的預處理精煉爐14中的鐵水15的脫磷處理的作業條件,在比較例及本發明例中均設定在以下的通常處理條件的範圍內。 The working conditions of the dephosphorization treatment of the molten iron 15 in the converter type pretreatment refining furnace 14 are set within the range of the following general processing conditions in both the comparative example and the present invention example.
1.脫磷處理前的鐵水15的溫度:1270℃~1320℃ 1. The temperature of molten iron 15 before dephosphorization treatment: 1270 ° C ~ 1320 ° C
2.脫磷處理前的鐵水15的矽濃度:0.25質量%~0.35質量% 2. Neodymium concentration of molten iron 15 before dephosphorization treatment: 0.25 mass% to 0.35 mass%
3.脫磷處理前的鐵水15的磷濃度:0.100質量%~0.120質量% 3. Phosphorus concentration of molten iron 15 before dephosphorization treatment: 0.100% by mass to 0.120% by mass
4.脫磷處理結束時的低磷鐵水的磷濃度:0.005質量%~0.030質量% 4. Phosphorus concentration of low-phosphorus molten iron at the end of dephosphorization treatment: 0.005 mass% to 0.030 mass%
5.脫磷處理結束時的爐內爐渣的鹼度:2.0~3.0 5. Alkalinity of furnace slag at the end of dephosphorization treatment: 2.0~3.0
6.脫磷處理結束時的爐內爐渣的總鐵濃度:5.0質量%~15.0質量% 6. Total iron concentration in the furnace slag at the end of the dephosphorization treatment: 5.0% by mass to 15.0% by mass
比較例1的試驗中,不將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8用作向預處理精煉爐14裝入的熱裝入原料,而是如現有般在自脫碳精煉爐3湧出鋼水5之後排出至渣桶中,且利用渣桶搬送至渣場,並流出至渣場而放置冷卻。 In the test of Comparative Example 1, the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace were not used as the heat-loaded raw materials charged into the pretreatment refining furnace 14, but were self-decarburized refining as in the prior art. The furnace 3 is discharged from the molten steel 5, discharged into the slag bucket, and transported to the slag yard by the slag bucket, and flows out to the slag yard to be placed and cooled.
即,將殘留熔融爐渣9及殘留鋼水8排出至精煉處理步驟的系統外來進行爐渣處理(大氣中的放置冷卻)及凝固鐵回收處理(固化後藉由磁選機而自破碎的爐渣回收凝固鐵)。然後,向300噸容量的轉爐型的預處理精煉爐14中預先裝入30噸鐵渣之後,裝入鐵水鍋中所收納的鐵水15來進行脫磷處理。在脫磷處理中不使用磁選屑、鐵礦石、鐵礦石的燒結礦等其他鐵源而進行脫磷處理。 In other words, the residual molten slag 9 and the residual molten steel 8 are discharged to the system outside the refining process to carry out slag treatment (placement cooling in the atmosphere) and solidified iron recovery treatment (after solidification, the solidified iron is recovered from the crushed slag by the magnetic separator) ). Then, 30 tons of iron slag is preliminarily charged into the converter-type pretreatment refining furnace 14 having a capacity of 300 tons, and then the molten iron 15 accommodated in the hot water pot is charged to perform dephosphorization treatment. Dephosphorization treatment is carried out without using other iron sources such as magnetic separators, iron ore, or iron ore sinter in the dephosphorization treatment.
比較例1的脫磷處理結束時的低磷鐵水的溫度為1280℃~1320℃的溫度範圍。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of Comparative Example 1 was in the range of 1280 ° C to 1320 ° C.
本發明例1中,在自脫碳精煉爐3湧出鋼水5之後,將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8全部快速地排出至在內表面形成有耐火物層的爐渣收納搬送容器10。在該爐渣收納搬送容器內對殘留熔融爐渣9及殘留鋼水8進行溫度測定的結果為,殘留熔融爐渣9及殘留鋼水8的溫度為1560℃~1610℃的範圍,即為鋼水及爐渣的熔融狀態的範圍。其後,將爐渣收納搬送容器10中所收納的約7噸殘留熔融爐渣9與約2噸殘留鋼水8全部裝入至預先裝入有30噸鐵渣的預處理精煉爐14中,然後裝入鐵水15而進行脫磷處理。為了確認與上述比較例1相對的處理後溫度的優越性,本發明例1中,亦不使用磁選屑、鐵礦石、鐵礦石的燒結礦等其他鐵源而進行脫磷處理。 In the first embodiment of the present invention, after the molten steel 5 is discharged from the decarburization refining furnace 3, the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace are all quickly discharged to the slag having the refractory layer formed on the inner surface. The transport container 10 is housed. As a result of measuring the temperature of the residual molten slag 9 and the residual molten steel 8 in the slag storage and transport container, the temperature of the residual molten slag 9 and the residual molten steel 8 is in the range of 1560 ° C to 1610 ° C, that is, molten steel and slag. The range of molten states. Thereafter, about 7 tons of residual molten slag 9 and about 2 tons of residual molten steel 8 stored in the slag storage and transport container 10 are all charged into a pretreatment refining furnace 14 in which 30 tons of iron slag is preliminarily loaded, and then loaded. The deionization treatment is carried out by entering the molten iron 15 . In order to confirm the superiority of the post-treatment temperature with respect to the above Comparative Example 1, in the first example of the present invention, the dephosphorization treatment was carried out without using other iron sources such as magnetic chips, iron ore, or iron ore sinter.
本發明例1的脫磷處理結束時的低磷鐵水的溫度成為1325℃~1365℃的溫度範圍,可確認出低磷鐵水的溫度較比較例1 高約45℃。該溫度差是由裝入至預處理精煉爐14中的殘留熔融爐渣9及殘留鋼水8的顯熱引起的。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of Example 1 of the present invention was in the range of 1325 ° C to 1365 ° C, and the temperature of the low-phosphorus molten iron was confirmed as compared with Comparative Example 1. It is about 45 ° C high. This temperature difference is caused by the sensible heat of the residual molten slag 9 and the residual molten steel 8 charged into the pretreatment refining furnace 14.
本發明例2中,自脫碳精煉爐3湧出鋼水5之後,將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8全部快速地排出至在內表面形成有耐火物層的爐渣收納搬送容器10中。其後,將爐渣收納搬送容器10中所收納的約7噸殘留熔融爐渣9與約2噸殘留鋼水8全部裝入至預先裝入有30噸鐵渣的預處理精煉爐14中,然後裝入鐵水15,進而自爐上方根據自殘留熔融爐渣9及殘留鋼水8的熱回收量,而添加包含鐵礦石、鐵礦石的燒結礦、鐵銹皮、煉鐵粉、磁選屑、鋼的切削屑的鐵源中的任1種或2種以上鐵源來進行脫磷處理。例如在為磁選屑的情形時,添加5噸~10噸。 In the second embodiment of the present invention, after the molten steel 5 is discharged from the decarburization refining furnace 3, all of the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace are quickly discharged to the slag storage in which the refractory layer is formed on the inner surface. Transfer to the container 10. Thereafter, about 7 tons of residual molten slag 9 and about 2 tons of residual molten steel 8 stored in the slag storage and transport container 10 are all charged into a pretreatment refining furnace 14 in which 30 tons of iron slag is preliminarily loaded, and then loaded. Into the molten iron 15, and then from the upper part of the furnace, according to the heat recovery amount of the residual molten slag 9 and the residual molten steel 8, adding sinter containing iron ore, iron ore, rust, iron powder, magnetic separator, steel Dephosphorization treatment is performed by any one or two or more kinds of iron sources of the chips. For example, in the case of magnetic selection, 5 tons to 10 tons are added.
本發明例2的脫磷處理結束時的低磷鐵水的溫度,為與比較例1相同的1280℃~1320℃的溫度範圍。如此,本發明例2中,即便追加添加磁選屑等鐵源,亦可無問題地作業,相對於比較例1而可使生產量增加。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of Example 2 of the present invention was the same temperature range of 1280 ° C to 1320 ° C as in Comparative Example 1. As described above, in the second example of the present invention, even if an iron source such as magnetic separator is additionally added, the operation can be performed without problems, and the production amount can be increased with respect to the comparative example 1.
本發明例3中,自脫碳精煉爐3湧出鋼水5之後,將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8全部快速地排出至在內表面形成有耐火物層的爐渣收納搬送容器10中。其後,將爐渣收納搬送容器10中所收納的約7噸殘留熔融爐渣9與約2噸殘留鋼水8全部裝入至預先裝入有35噸~40噸鐵渣的預處理精煉爐14中,然後裝入鐵水15而進行脫磷處理。如此,本發明例3中,相對於比較例1的30噸,而使預先裝入至預處理精煉爐14中的 鐵渣量進而增加5噸~10噸。 In the third embodiment of the present invention, after the molten steel 5 is discharged from the decarburization refining furnace 3, all of the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace are quickly discharged to the slag containing the refractory layer formed on the inner surface. Transfer to the container 10. Thereafter, about 7 tons of residual molten slag 9 and about 2 tons of residual molten steel 8 accommodated in the slag storage and transport container 10 are all charged into the pretreatment refining furnace 14 which is previously charged with 35 to 40 tons of iron slag. Then, the molten iron 15 is charged to perform dephosphorization treatment. Thus, in the third example of the present invention, it was previously charged into the pretreatment refining furnace 14 with respect to 30 tons of the comparative example 1. The amount of iron slag is further increased by 5 tons to 10 tons.
本發明例3的脫磷處理結束時的低磷鐵水的溫度,為與比較例1相同的1280℃~1320℃的溫度範圍。如此,本發明例3中,即便增加鐵渣的使用量,亦可無問題地作業,相對於比較例1而可使生產量增加。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of Example 3 of the present invention was the same temperature range of 1280 ° C to 1320 ° C as in Comparative Example 1. As described above, in the third example of the present invention, even if the amount of iron slag used is increased, the operation can be performed without problems, and the production amount can be increased with respect to the comparative example 1.
本發明例4中,自脫碳精煉爐3湧出鋼水5之後,將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8全部快速地排出至在內表面形成有耐火物層的爐渣收納搬送容器10中。本發明例4中,以併用預先裝入至預處理精煉爐14中而使用的鐵渣與自爐上方投入添加的鐵源為前提,且使裝入至預處理精煉爐14中的鐵渣量為30噸~40噸,並根據該鐵渣的裝入量而設定自爐上方投入添加的鐵源的使用量。具體而言,使預先裝入的鐵渣與自爐上方投入添加的鐵源的合計量為40噸。 In the fourth example of the present invention, after the molten steel 5 is poured out from the decarburization refining furnace 3, the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace are all quickly discharged to the slag storage in which the refractory layer is formed on the inner surface. Transfer to the container 10. In the fourth embodiment of the present invention, the iron slag used in advance in the pretreatment refining furnace 14 is used in combination with the iron source added from above the furnace, and the amount of iron slag charged into the pretreatment refining furnace 14 is used. It is 30 tons to 40 tons, and the amount of iron source to be added from above the furnace is set according to the amount of iron slag charged. Specifically, the total amount of iron slag charged in advance and iron source added from above the furnace was 40 tons.
即,將形成有耐火物層的爐渣收納搬送容器10中所收納的約7噸殘留熔融爐渣9與約2噸殘留鋼水8全部裝入至預先裝入有30噸~40噸鐵渣的預處理精煉爐14中之後,裝入鐵水15。其後,以預先裝入的鐵渣的質量與自爐上方投入的鐵源的質量的合計質量成為40噸的方式,根據預先裝入至爐內的鐵渣量而將以下鐵源設定在0噸~10噸的範圍內來添加,其後進行脫磷處理,上述鐵源為自爐上方投入的包含鐵礦石、鐵礦石的燒結礦、鐵銹皮、煉鐵粉、磁選屑、鋼的切削屑的鐵源中的任1種或2種以上的鐵源。 In other words, about 7 tons of residual molten slag 9 and about 2 tons of residual molten steel 8 stored in the slag storage and transport container 10 in which the refractory layer is formed are all loaded into a precharged with 30 tons to 40 tons of iron slag. After the treatment of the refining furnace 14, the molten iron 15 is charged. Then, the total mass of the iron slag charged in advance and the mass of the iron source charged from above the furnace was 40 tons, and the following iron source was set to 0 based on the amount of iron slag previously charged into the furnace. It is added in the range of ton~10 tons, and then dephosphorization treatment. The above iron source is sinter containing iron ore, iron ore, rust skin, iron powder, magnetic separator, steel imported from above the furnace. Any one or two or more kinds of iron sources of the iron source of the chips.
本發明例4的脫磷處理結束時的低磷鐵水的溫度,為與比較例1相同的1280℃~1320℃的溫度範圍。如此,本發明例4中,即便增加預先裝入的鐵渣量或追加添加磁選屑等鐵源,亦可無問題地作業,相對於比較例1而可使生產量增加。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of Example 4 of the present invention was the same temperature range of 1280 ° C to 1320 ° C as in Comparative Example 1. As described above, in the fourth example of the present invention, even if an iron source such as a pre-loaded iron slag is added or an iron source such as magnetic separator is additionally added, the operation can be performed without problems, and the production amount can be increased with respect to the comparative example 1.
本發明例5中,自脫碳精煉爐3湧出鋼水5之後,將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8全部快速地排渣至裝入有20噸~30噸鐵渣的金屬製的爐渣收納搬送容器11中。流出至爐渣收納搬送容器11中的殘留熔融爐渣9及殘留鋼水8與鐵渣接觸而冷卻,從而形成有約9噸的含金屬爐渣13。 In the fifth example of the present invention, after the molten steel 5 is discharged from the decarburization refining furnace 3, the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace are all quickly discharged to the slag containing 20 to 30 tons of iron slag. The metal slag is stored in the transfer container 11. The residual molten slag 9 and the residual molten steel 8 which have flowed out into the slag storage and conveyance container 11 are cooled by contact with the iron slag, and about 9 tons of metal-containing slag 13 are formed.
本發明例5中,包含自爐上方投入的鐵源在內將脫磷處理中所使用的鐵渣量設定為40噸。即,使預先裝入至預處理精煉爐14中的鐵渣量為10噸,將金屬製的爐渣收納搬送容器11中所收納的20噸~30噸鐵渣與約9噸的含金屬爐渣13一同全部裝入至預處理精煉爐14中之後,裝入鐵水15。其後,根據自爐渣收納搬送容器11裝入的鐵渣量而將包含鐵礦石、鐵礦石的燒結礦、鐵銹皮、煉鐵粉、磁選屑、鋼的切削屑的鐵源中的任1種或2種以上鐵源設定在0噸~10噸的範圍內,並自爐上方添加該設定的量而進行脫磷處理。 In Inventive Example 5, the amount of iron slag used in the dephosphorization treatment was set to 40 tons including the iron source charged from above the furnace. In other words, the amount of iron slag previously charged into the pretreatment refining furnace 14 is 10 tons, and the metal slag is accommodated in the transport container 11 and contains 20 tons to 30 tons of iron slag and about 9 tons of metal-containing slag 13 After being completely charged into the pretreatment refining furnace 14, the molten iron 15 is charged. Then, depending on the amount of iron slag charged in the slag storage and transport container 11, any iron source containing iron ore, iron ore sinter, iron scale, iron powder, magnetic separator, and steel chips is used. One or two or more kinds of iron sources are set in the range of 0 to 10 tons, and the set amount is added from above the furnace to perform dephosphorization treatment.
本發明例5的脫磷處理結束時的低磷鐵水的溫度,為與比較例1相同的1280℃~1320℃的溫度範圍。如此,本發明例5中,即便追加添加磁選屑等鐵源,亦可無問題地作業,可使生產量增加。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of Example 5 of the present invention was the same temperature range of 1280 ° C to 1320 ° C as in Comparative Example 1. As described above, in the fifth example of the present invention, even if an iron source such as magnetic separator is additionally added, the operation can be performed without problems, and the throughput can be increased.
本發明例6中,自脫碳精煉爐3湧出鋼水5之後,將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8全部快速地排渣至裝入有30噸~40噸鐵渣的金屬製的爐渣收納搬送容器11中。流出至爐渣收納搬送容器11中的殘留熔融爐渣9及殘留鋼水8與鐵渣接觸而冷卻,從而形成有約9噸的含金屬爐渣13。 In the sixth embodiment of the present invention, after the molten steel 5 is discharged from the decarburization refining furnace 3, the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace are all quickly discharged to the slag containing 30 to 40 tons of iron slag. The metal slag is stored in the transfer container 11. The residual molten slag 9 and the residual molten steel 8 which have flowed out into the slag storage and conveyance container 11 are cooled by contact with the iron slag, and about 9 tons of metal-containing slag 13 are formed.
本發明例6中,使預先裝入至預處理精煉爐14中的鐵渣量為零,並且包含自爐上方投入的鐵源在內而將脫磷處理中所使用的鐵渣量設定為40噸。即,將爐渣收納搬送容器11中所收納的30噸~40噸鐵渣與約9噸的含金屬爐渣13一同全部裝入至預處理精煉爐14中之後,裝入鐵水15。其後,根據自爐渣收納搬送容器11裝入的鐵渣量而將包含鐵礦石、鐵礦石的燒結礦、鐵銹皮、煉鐵粉、磁選屑、鋼的切削屑的鐵源中的任1種或2種以上鐵源設定在0噸~10噸的範圍內,並自爐上方添加該設定的量而進行脫磷處理。 In the sixth example of the present invention, the amount of iron slag previously charged into the pretreatment refining furnace 14 is zero, and the amount of iron slag used in the dephosphorization treatment is set to 40 including the iron source charged from above the furnace. Ton. In other words, the 30 to 40 tons of iron slag contained in the slag storage and transportation container 11 and the metal-containing slag 13 of about 9 tons are all charged into the pretreatment refining furnace 14 and then the molten iron 15 is charged. Then, depending on the amount of iron slag charged in the slag storage and transport container 11, any iron source containing iron ore, iron ore sinter, iron scale, iron powder, magnetic separator, and steel chips is used. One or two or more kinds of iron sources are set in the range of 0 to 10 tons, and the set amount is added from above the furnace to perform dephosphorization treatment.
本發明例6的脫磷處理結束時的低磷鐵水的溫度,為與比較例1相同的1280℃~1320℃的溫度範圍。又,本發明例6中,不單獨向預處理精煉爐14裝入鐵渣,藉此,可將亦使包含殘留熔融爐渣9的裝入時間及鐵渣12的裝入時間等在內的脫磷處理時間間隔縮短10%左右,亦外加鐵渣及磁選屑等鐵源的裝入所帶來的生產量的增加的作用而可使生產性提高。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of Example 6 of the present invention was the same temperature range of 1280 ° C to 1320 ° C as in Comparative Example 1. Further, in the sixth embodiment of the present invention, the iron slag is not separately charged into the pretreatment refining furnace 14, whereby the charging time including the residual molten slag 9 and the charging time of the iron slag 12 can be removed. The phosphorus treatment time interval is shortened by about 10%, and the productivity is increased by the effect of the increase in the production amount of the iron source such as iron slag and magnetic separator.
本發明例7中,自脫碳精煉爐3湧出鋼水5之後,將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8全部快速地排渣至裝 入有30噸~40噸鐵渣的金屬製的爐渣收納搬送容器11中。流出至爐渣收納搬送容器11中的殘留熔融爐渣9及殘留鋼水8與鐵渣接觸而冷卻,從而形成有約9噸的含金屬爐渣13。 In the seventh embodiment of the present invention, after the molten steel 5 is discharged from the decarburization refining furnace 3, the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace are all quickly discharged to the loading. A metal slag having 30 to 40 tons of iron slag is stored in the transfer container 11. The residual molten slag 9 and the residual molten steel 8 which have flowed out into the slag storage and conveyance container 11 are cooled by contact with the iron slag, and about 9 tons of metal-containing slag 13 are formed.
本發明例7中,作為預處理精煉爐14中的預處理而採用如下方法,即在主要對鐵水進行脫矽處理的脫矽期之後暫時中斷氧吹煉而對爐內的爐渣進行排渣(稱為「中間排渣」),其後向預處理精煉爐14中添加生石灰而對鐵水進行脫磷(脫磷期)。將脫矽期結束時間點的爐內爐渣的鹼度調整為1.0~1.5的範圍,在將吹煉中斷4分鐘左右的期間,以殘留10kg/鐵水-t左右的爐內爐渣的方式實施中間排渣。又,本發明例7中,使預先裝入至預處理精煉爐14中的鐵渣量為零,並且包含自爐上方投入的鐵源在內而將脫磷處理中所使用的鐵渣量設定為40噸。 In the seventh aspect of the present invention, as the pretreatment in the pretreatment refining furnace 14, a method of temporarily interrupting the oxygen blowing and discharging the slag in the furnace after the deodorization period in which the molten iron is mainly subjected to the deodorization treatment is employed. (referred to as "intermediate slag discharge"), after which quicklime is added to the pretreatment refining furnace 14 to dephosphorize the molten iron (dephosphorization period). In the range of 1.0 to 1.5, the alkalinity of the slag in the furnace at the end of the de-salting period is adjusted to a range of 1.0 to 1.5, and the intermediate slag of about 10 kg/iron-t is left in the middle of the interruption of the blowing for about 4 minutes. Drainage. Further, in the seventh embodiment of the present invention, the amount of iron slag previously charged into the pretreatment refining furnace 14 is zero, and the amount of iron slag used in the dephosphorization treatment is set including the iron source charged from above the furnace. It is 40 tons.
即,將金屬製的爐渣收納搬送容器11中所收納的30噸~40噸鐵渣與約9噸的含金屬爐渣13一同全部裝入至預處理精煉爐14中之後,裝入鐵水15。其後,根據自爐渣收納搬送容器11裝入的鐵渣量而將包含鐵礦石、鐵礦石的燒結礦、鐵銹皮、煉鐵粉、磁選屑、鋼的切削屑的鐵源中的任1種或2種以上鐵源設定在0噸~10噸的範圍內,並自爐上方添加該設定的量而進行脫矽、脫磷處理。 In other words, the 30 to 40 tons of iron slag contained in the metal slag storage and transport container 11 is placed in the pretreatment refining furnace 14 together with about 9 tons of the metal containing slag 13 and then the molten iron 15 is charged. Then, depending on the amount of iron slag charged in the slag storage and transport container 11, any iron source containing iron ore, iron ore sinter, iron scale, iron powder, magnetic separator, and steel chips is used. One or two or more kinds of iron sources are set in the range of 0 to 10 tons, and the set amount is added from the upper side of the furnace to perform depurination and dephosphorization treatment.
本發明例7的脫磷處理結束時的低磷鐵水的溫度為1280℃~1320℃的溫度範圍,脫磷處理結束時的低磷鐵水的磷濃度為0.005質量%~0.020質量%。相對於在脫矽期之後不進行中 間排渣的本發明例1~本發明例6及比較例1,本發明例7的脫磷處理結束時的低磷鐵水的磷濃度降低。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of the seventh embodiment of the present invention is in the temperature range of 1280 ° C to 1320 ° C, and the phosphorus concentration of the low-phosphorus molten iron at the end of the dephosphorization treatment is 0.005 mass % to 0.020 mass %. Not in progress after the dislocation period In the inventive example 1 to the inventive example 6 and the comparative example 1, the phosphorus concentration of the low-phosphorus molten iron at the end of the dephosphorization treatment of the inventive example 7 was lowered.
如此,本發明例7中,在脫矽期之後進行中間排渣,藉此防止自殘留熔融爐渣9的復磷,從而可使脫磷處理結束時的低磷鐵水磷濃度降低。 As described above, in the seventh aspect of the present invention, the intermediate slag is discharged after the devolatilization period, thereby preventing the rephosphorization from the residual molten slag 9, and the phosphorus concentration of the low phosphorus iron phosphate at the end of the dephosphorization treatment can be lowered.
本發明例8中,自脫碳精煉爐3湧出鋼水5之後,將脫碳精煉爐內的殘留熔融爐渣9及殘留鋼水8全部快速地排渣至裝入有35噸~40噸鐵渣的金屬製的爐渣收納搬送容器11中。流出至爐渣收納搬送容器11中的殘留熔融爐渣9及殘留鋼水8與鐵渣接觸而冷卻,從而形成有約9噸的含金屬爐渣13。 In the eighth embodiment of the present invention, after the molten steel 5 is discharged from the decarburization refining furnace 3, the residual molten slag 9 and the residual molten steel 8 in the decarburization refining furnace are all quickly discharged to the slag containing 35 to 40 tons of iron slag. The metal slag is stored in the transfer container 11. The residual molten slag 9 and the residual molten steel 8 which have flowed out into the slag storage and conveyance container 11 are cooled by contact with the iron slag, and about 9 tons of metal-containing slag 13 are formed.
本發明例8中,作為預處理而採用如下方法,即,維持使預處理精煉爐14中的預填充的脫磷處理後的爐渣殘留在爐內的狀態而裝入該填充的鐵水來開始預處理精煉,在主要對鐵水進行脫矽處理的脫矽期之後暫時中斷氧吹煉,對爐內的爐渣進行中間排渣,其後,向預處理精煉爐14添加生石灰來對鐵水進行脫磷(脫磷期)。將脫矽期結束時間點的爐內爐渣的鹼度調整為1.0~1.5的範圍,在將吹煉中斷4分鐘左右的期間,以殘留10kg/鐵水-t左右的爐內爐渣的方式實施中間排渣。又,本發明例8中,使預先裝入至預處理精煉爐14中的鐵渣量為零,並且包含自爐上方投入的鐵源在內而將脫磷處理中所使用的鐵渣量設定為42噸。 In the eighth aspect of the present invention, as a pretreatment, a method in which the slag after the pre-refilled dephosphorization treatment in the pretreatment refining furnace 14 is left in the furnace is maintained, and the filled molten iron is charged and started. The pretreatment refining temporarily interrupts the oxygen blowing after the dislocation period in which the molten iron is subjected to the deodorization treatment, and performs intermediate slagging on the slag in the furnace, and thereafter, adding the quicklime to the pretreatment refining furnace 14 to carry out the molten iron Dephosphorization (dephosphorization period). In the range of 1.0 to 1.5, the alkalinity of the slag in the furnace at the end of the de-salting period is adjusted to a range of 1.0 to 1.5, and the intermediate slag of about 10 kg/iron-t is left in the middle of the interruption of the blowing for about 4 minutes. Drainage. Further, in the eighth embodiment of the present invention, the amount of iron slag previously charged into the pretreatment refining furnace 14 is zero, and the amount of iron slag used in the dephosphorization treatment is set including the iron source charged from above the furnace. It is 42 tons.
即,將金屬製的爐渣收納搬送容器11中所收納的35噸~40噸鐵渣與約9噸的含金屬爐渣13一同全部裝入至預處理精煉 爐14中之後,裝入鐵水15。其後,根據自爐渣收納搬送容器11裝入的鐵渣量而將包含鐵礦石、鐵礦石的燒結礦、鐵銹皮、煉鐵粉、磁選屑、鋼的切削屑的鐵源中的任1種或2種以上鐵源設定在2噸~7噸的範圍內,自爐上方添加該設定的量而進行脫矽、脫磷處理。 In other words, 35 to 40 tons of iron slag contained in the metal slag storage and transport container 11 is loaded together with about 9 tons of metal-containing slag 13 to the pretreatment refining. After the furnace 14, the molten iron 15 is charged. Then, depending on the amount of iron slag charged in the slag storage and transport container 11, any iron source containing iron ore, iron ore sinter, iron scale, iron powder, magnetic separator, and steel chips is used. One or two or more kinds of iron sources are set in the range of 2 tons to 7 tons, and the set amount is added from the upper side of the furnace to perform depurination and dephosphorization treatment.
本發明例8的脫磷處理結束時的低磷鐵水的溫度為1280℃~1320℃的溫度範圍,脫磷處理結束時的低磷鐵水的磷濃度為0.005質量%~0.020質量%。相對於在脫矽期之後不進行中間排渣的本發明例1~本發明例6及比較例1,本發明例8的脫磷處理結束時的低磷鐵水的磷濃度降低,成為與本發明例7相同的程度。 The temperature of the low-phosphorus molten iron at the end of the dephosphorization treatment of the eighth embodiment of the present invention is in the temperature range of 1280 ° C to 1320 ° C, and the phosphorus concentration of the low-phosphorus molten iron at the end of the dephosphorization treatment is 0.005 mass % to 0.020 mass %. The phosphorus concentration of the low-phosphorus iron water at the end of the dephosphorization treatment of the eighth embodiment of the present invention is lowered with respect to the present invention example 1 to the present invention example 6 and the comparative example 1 in which the intermediate slag is not discharged after the devolatilization period. Inventive Example 7 was the same degree.
如此,本發明例8中,重複利用脫磷處理後的爐渣,並且在脫矽期之後進行中間排渣,藉此可防止自重複利用的脫磷處理後的爐渣及殘留熔融爐渣9的復磷,從而可使脫磷處理結束時的低磷鐵水磷濃度降低。又,將重複利用的脫磷處理後的爐渣活用作脫矽期的精煉劑,藉此亦可更有效地利用脫磷處理後的爐渣所保有的顯熱。 As described above, in the eighth embodiment of the present invention, the slag after the dephosphorization treatment is repeatedly used, and the intermediate slag is discharged after the deuteration period, whereby the re-phosphorization of the slag after the dephosphorization treatment and the residual molten slag 9 can be prevented. Therefore, the phosphorus concentration of the low-phosphorus iron phosphate at the end of the dephosphorization treatment can be lowered. Further, the slag after the dephosphorization treatment which is repeatedly used is used as a refining agent in the delining period, whereby the sensible heat retained by the slag after the dephosphorization treatment can be more effectively utilized.
將比較例1及本發明例1~本發明例8的結果匯總示於表1。 The results of Comparative Example 1 and Inventive Example 1 to Inventive Example 8 are collectively shown in Table 1.
1‧‧‧預處理步驟 1‧‧‧Pretreatment steps
2‧‧‧低磷鐵水 2‧‧‧Low-phosphorus molten iron
2'‧‧‧脫矽鐵水 2'‧‧‧Destroyed hot metal
3‧‧‧脫碳精煉爐 3‧‧‧Decarbonization refining furnace
4‧‧‧脫碳精煉步驟 4‧‧‧Decarbonization refining steps
5‧‧‧鋼水 5‧‧‧Steel
6‧‧‧熔融爐渣(脫碳爐渣) 6‧‧‧Fusing slag (decarburization slag)
7‧‧‧鋼包 7‧‧‧Ladle
8‧‧‧殘留鋼水 8‧‧‧Residual molten steel
9‧‧‧殘留熔融爐渣 9‧‧‧Residual molten slag
10、11‧‧‧爐渣收納搬送容器 10, 11‧‧‧ slag storage transport container
10a‧‧‧耐火物層 10a‧‧‧ refractory layer
12‧‧‧鐵渣 12‧‧‧ iron slag
13‧‧‧含金屬爐渣 13‧‧‧Metal slag
14‧‧‧預處理精煉爐 14‧‧‧Pretreatment refining furnace
15‧‧‧鐵水 15‧‧‧ molten iron
16‧‧‧所有熔融金屬 16‧‧‧All molten metal
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