KR20010036627A - Method for improving desulfurization ratio of desiliconized molten pig iron in hot metal pretreatment - Google Patents

Method for improving desulfurization ratio of desiliconized molten pig iron in hot metal pretreatment Download PDF

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KR20010036627A
KR20010036627A KR1019990043728A KR19990043728A KR20010036627A KR 20010036627 A KR20010036627 A KR 20010036627A KR 1019990043728 A KR1019990043728 A KR 1019990043728A KR 19990043728 A KR19990043728 A KR 19990043728A KR 20010036627 A KR20010036627 A KR 20010036627A
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molten iron
cao
slag
injecting
molten metal
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KR100402011B1 (en
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지용태
안승환
최인섭
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이구택
포항종합제철 주식회사
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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
    • 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
    • C21C1/025—Agents used for dephosphorising or desulfurising

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)

Abstract

PURPOSE: A method for increasing desulfurization efficiency of desiliconized hot metal in the pretreatment process is provided to optimize the desulfurization efficiency by injecting Al-CaO flux before desulfurizing the hot metal, and reduce operation load after the converter process by decreasing desulfurizing time through reduction of basic unit of desulfurizers, and securing stable sulfur level after desulfurization. CONSTITUTION: The method comprises the process of securing 3.5% or less of degree of oxidation and 1.2 or more of basicity of the molten metal slag by injecting 1.0 to 1.5 kg of Al-CaO flux per ton of molten metal into upper part of the molten metal slag before injecting the desulfurizer in a pretreatment method in which molten metal is desulfurized by injecting desulfurizer into desiliconized molten metal carried on a ladle, wherein the Al-CaO flux comprises 20 to 30 wt.% of CaO and a balance of a major constituent of Al.

Description

예비처리공정에서 탈규용선의 탈류효율증대방법{Method for improving desulfurization ratio of desiliconized molten pig iron in hot metal pretreatment}Method for improving desulfurization ratio of desiliconized molten pig iron in hot metal pretreatment

본 발명은 탈규용선를 탈류처리하는 용선예비처리 방법에 관한 것으로, 보다 상세하게는 탈류처리전에 Al-CaO계 플럭스를 투입하여 탈류반응효율을 극대화하는 방법을 관한 것이다.The present invention relates to a molten iron preliminary treatment method for the deflow treatment of degreasing molten iron, and more particularly, to a method for maximizing the deflow reaction efficiency by introducing Al-CaO flux before the deflow treatment.

용선예비처리는 도 1같이 고로의 용선을 전로에 장입하기 전에 탈린, 탈류 등의 처리를 행하는 것으로, 고로의 용선을 제강공정으로 운반하는 래들에 따라 토페이도 래들(TLC; Torppedo Ladle Car)(도 2(a))과 오픈래들(OLC; Open Ladle Car)(도 2(b))로 구분된다.The molten iron preliminary treatment is a process of delineation, dehydration, etc. before charging the molten iron of the blast furnace into the converter, and according to the ladle carrying the molten iron of the blast furnace to the steelmaking process (TLC; Torppedo Ladle Car) ( 2 (a)) and open ladle (OLC; Open Ladle Car) (Fig. 2 (b)).

용선예비처리에서 탈류조업은, 래들의 용선에 랜스를 침적시키고 이 랜스를 통해 질소가스로 용선탈류제를 용선에 약 20-25분간 취입하여 용선중의 [S]을 저감시키는 방법(도 2(a))과 용선탈류제를 투입한 후 기계적 교반력을 이용하여 탈류하는 방법(도 2(b))이 있다. 보통 탈류제로는 CaC2, CaO가 사용되고 있으며, 이들의 탈류반응식은 아래와 같다.In the molten iron preliminary treatment, the leaching operation is a method of reducing the [S] in the molten iron by depositing a lance on the molten iron of the ladle and injecting the molten iron desorbent into the molten iron for about 20-25 minutes through the lance. After a)) and the molten iron desorbent is introduced, there is a method of dehydration using mechanical stirring force (Fig. 2 (b)). Usually, as the desorbing agent, CaC 2 , CaO are used, and their dehydration reaction formula is as follows.

CaC2+ S = CaS + 2CCaC 2 + S = CaS + 2C

CaC2+ FeS = CaS + 2C + FeCaC 2 + FeS = CaS + 2C + Fe

2FeS + 4CaO + Si = 2Fe + 2CaS + Ca2SiO4 2FeS + 4CaO + Si = 2Fe + 2CaS + Ca2SiO 4

2FeS + 4CaO + Si = 2Fe + 2CaS + SiO2 2FeS + 4CaO + Si = 2Fe + 2CaS + SiO 2

이와 같이 탈류반응은 환원반응이기 때문에 강산화성 분위기에서 취련하는 전로공정에서는 탈류반응의 효과를 기대할 수 없어 용선예비처리단계에서 탈류처리를 하고 있다.As the dehydration reaction is a reduction reaction, the desulfurization reaction cannot be expected in the converter process of blowing in a strong oxidizing atmosphere.

한편, 최근 들어 저린강, 고합금강 등 고급강 생산이 늘면서 전로 출강후에 노외정련 공정이 불가피해짐에 따라, 전로 출강온도의 상승과 함께 전로취련시 탈린에 대한 부하가 증가하는 문제점이 대두됨과 동시에 전로 슬라그 발생량 저감을 통하여 환경문제(전로 슬로핑)을 저감하기 위해서 용선의 규소성분을 전로 장입전에 낮추는 것이 요구되고 있다.On the other hand, as the production of high-grade steel, such as low-lining steel and high-alloy steel, has been inevitable since the off-road refining process is inevitable after going out of the converter, the problem of increasing the load on the converter and increasing the load on Tallinn when the converter is being worked on. In order to reduce the environmental problems (converter slope) by reducing the amount of converter slag, it is required to lower the silicon content of the molten iron before charging the converter.

이러한 요구에 맞추어 고로에서는 출선중에 산화철이 70% 수준의 소결반광이나 소결더스트(Dust)을 용선에 투입하는 용선탈규조업을 하고 있다. 이때, 발생되는 탈규반응식은 아래와 같다.In response to these demands, the blast furnace is performing molten iron removal business in which 70% of iron oxide is injected into molten iron during sintered reflection or dust. At this time, the desulfurization reaction generated is as follows.

2[FeO] + [Si] → (SiO2) + 2[Fe]2 [FeO] + [Si] → (SiO 2 ) + 2 [Fe]

이와 같이 탈규된 용선은 아래 표1에서와 같이 일반용선 대비 슬래그의 규소산화물(SiO2)의 증가로 슬래그의 염기도(CaO/SiO2)가 낮고, 용선중에 투입된 소결반광 및 소결더스트의 미반응물이 남아 있어 슬래그의 산화물(T.Fe)이 증가된다.As described in Table 1 below, the demelted molten iron has a lower slag basicity (CaO / SiO 2 ) due to an increase in the silicon oxide (SiO 2 ) of the slag compared to the general molten iron. Remaining to increase the oxide of slag (T.Fe).

구분division T.Fe(중량%)T.Fe (% by weight) MnO(중량%)MnO (% by weight) 염기도(CaO/SiO2)Basicity (CaO / SiO 2 ) 일반용선Charter 1.41(0.71∼2.59)1.41 (0.71-2.59) 1.43(0.71∼2.4)1.43 (0.71-2.4) 1.15(0.84∼1.34)1.15 (0.84-1.34) 탈규용선Deregulation Chart 3.22(1.12∼12.64)3.22 (1.12-12.64) 2.88(0.4∼9.01)2.88 (0.4-9.01) 0.80(0.34∼1.83)0.80 (0.34-1.83)

이러한 변화는 탈류반응 효율을 저하시키는 문제을 대두시키고 있다(표 2).This change raises the problem of lowering the efficiency of dehydration reaction (Table 2).

구분division CaC2탈류제 사용Use of CaC 2 Desorbent 분CaO 탈류제 사용Use of CaO desorbent 전[S](중량%)All [S] (wt%) 후[S](중량%)After [S] (wt%) 원단위(kg/t-p)Unit (kg / t-p) 반응효율(K')Reaction efficiency (K ') 전[S](중량%)All [S] (wt%) 후[S](중량%)After [S] (wt%) 원단위(kg/t-p)Unit (kg / t-p) 반응효율(K')Reaction efficiency (K ') 일반용선Charter 20.520.5 4.14.1 4.114.11 0.390.39 18.818.8 5.15.1 6.976.97 0.190.19 탈규용선Deregulation Chart 21.021.0 5.65.6 5.255.25 0.250.25 18.118.1 6.16.1 8.378.37 0.130.13 차이Difference +0.5+0.5 +1.5+1.5 +1.14+1.14 -0.14-0.14 +0.7+0.7 +1.0+1.0 +1.40+1.40 -0.06-0.06

지금까지는 단순히 탈류제의 원단위를 증가시켜서 목표로 하는 탈류효율을 확보하고 있다. 그러나, 이 방법은 탈류제 원단위를 증가시킬 뿐 아니라, 탈류처리시간을 4-5분/TLC 정도 증가시키는 문제점을 가지고 있어 생산부하가 발생되고 있다. 더욱이, 탈류처리후에도 [S]수준이 일반용선 대비 평균 10ppm 높아 전로 이후 공정 즉, 버블링공정에서의 [S]을 낮추기 위한 버블링시간이 추가로 요구되는 문제가 있다.Until now, it has secured the target degassing efficiency by simply increasing the raw unit of the degassing agent. However, this method not only increases the denitrification unit but also has a problem of increasing the degassing treatment time by about 4-5 minutes / TLC, resulting in a production load. Furthermore, even after dehydration, the [S] level is on average 10 ppm higher than that of the general molten iron, and there is a problem that a bubbling time for lowering the [S] in the post-conversion process, that is, the bubbling process, is additionally required.

본 발명은 탈류처리전 Al-CaO계 플럭스를 투입함으로써 용선슬래그의 산화도 및 염기도 향상을 통해 탈류효율을 개선할 수 있는 방법을 제공하는데, 그 목적이 있다.The present invention provides a method for improving the degassing efficiency by improving the oxidation degree and basicity of molten iron slag by injecting the Al-CaO flux before the deflow process.

도 1은 강의 일반적인 제조공정도1 is a general manufacturing process diagram of steel

도 2는 탈류처리 개략도로서2 is a schematic diagram of dehydration treatment

도 2(a)는 토페이도 래들의 분체취입에 의한 탈류처리방법Figure 2 (a) is a dehydration treatment method by blowing the powder of toeido ladle

도 2(b)는 오픈래들의 기계적반응에 의한 탈류처리방법Figure 2 (b) is a deflow treatment method by the mechanical reaction of the open ladle

도 3은 슬래그 염기도에 따른 탈류효율을 나타내는 그래프3 is a graph showing the degassing efficiency according to the slag basicity

도 4는 Al-CaO계 플럭스 투입량에 따른 탈류효율을 나타내는 그래프4 is a graph showing the dehydration efficiency according to the Al-CaO flux input amount

도 5는 Al-CaO계 플럭스 투입량에 따른 용선슬래그의 조성변화를 나타내는 그래프5 is a graph showing the composition change of molten iron slag according to the Al-CaO flux input amount

도 6은 Al-CaO계 플럭스 투입시점에 따른 탈류반응효율을 나타내는 그래프6 is a graph showing the dehydration reaction efficiency according to the time of Al-CaO flux input

*도면의 주요부분에 대한 보호의 설명** Description of protection for the main parts of the drawing *

10.....토페도 래들 카 11.....랜스10 ..... Topedo Ladle Car 11 ..... Lance

20.....오픈 래들 카 21.....교반기20 ..... Open Ladle Car 21 ..... Agitator

상기 목적을 달성하기 위한 본 발명의 탈류효율증대방법은, 래들에 수선된 탈규용선에 탈류제를 투입하기전에 Al-CaO계 플럭스를 용선슬래그의 상부에 용선톤당 1.0∼1.5kg 투입하여 상기 용선슬래그의 산화도를 3.5%이하, 염기도를 1.2이상으로 확보하는 것을 포함하여 구성된다.In order to achieve the above object, the degassing efficiency increasing method of the present invention is carried out by adding 1.0-1.5 kg per molten ton of Al-CaO flux to the upper part of the molten iron slag before injecting the degreasing agent into the deregulated molten iron in the ladle. And the degree of oxidation of 3.5% or less and the basicity of 1.2 or more.

이하, 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail.

본 발명의 대상용선은 탈규용선으로서, 통상 0.25∼1.2% 정도로 용선이 탈규되고 있다. 이와 같이 탈규된 용선은 슬래그의 산화도(T.Fe+MnO)가 약 6.0중량%이상이며, 염기도가 1.0이하이다.The target molten iron of the present invention is a degreasing molten iron, and molten iron is usually desulfurized at about 0.25 to 1.2%. The molten iron melted in this manner has an oxidation degree (T.Fe + MnO) of the slag of about 6.0% by weight or more and a basicity of 1.0 or less.

본 발명자들은 이러한 탈규용선에 대하여 탈류효율개선방안을 찾던중, 슬래그의 염기도와 산화도가 탈류효율에 미치는 영향을 인식하게 되었다. 도 3에서와 같이, 탈류제의 종류에 관계 없이 염기도가 증가함에 따라 탈류율(Sulphur Capacity; (S)%/[S]%)은 증가됨을 알 수 있다. 이와 더불어, 탈규용선의 용선슬래그 분석결과 저급산화물의 함량이 높으면 탈류효율이 낮아진다는 것도 알게 되었다.The present inventors came to recognize the effect of the slag basicity and oxidation degree on the degassing efficiency while searching for a method for improving the degassing efficiency with respect to the deregulation molten iron. As shown in FIG. 3, it can be seen that as the basicity increases regardless of the type of the desorbent, the desulfurization rate (Sul% capacity (S)% / [S]%) increases. In addition, analysis of the molten iron slag of the degreasing molten iron found that the higher the content of the lower oxide, the lower the degassing efficiency.

따라서, 본 발명자들은 탈규용선의 탈류제 투입전에 용선슬래그의 염기도를 높이면서 산화도를 낮추면은 탈류효율을 개선시킬 수 있다는데 착안하여, 탈류제 투입전에 Al-CaO계 플럭스를 적용하게 되었다. Al-CaO계 플럭스중에서 Al은 용선슬래그의 산화도를 낮추고, CaO는 슬래그의 염기도를 향상시키는 작용을 한다.Accordingly, the present inventors have focused on improving the deflow efficiency by increasing the basicity of the molten iron slag and adding the molten iron slag before the desulfurizing agent is added to the desulfurizer, and thus applying the Al-CaO flux before the desulfurizing agent. In Al-CaO flux, Al lowers the oxidation degree of molten iron slag, and CaO improves the basicity of slag.

본 발명에서 이용하는 Al-CaO계 플럭스는 Al과 CaO를 주성분으로 하는 것이면 가능하며, 플럭스에서 Al과 CaO는 용선톤당 1.5kg이하로 하면서 용선슬래그의 염기도 및 산화도를 목적범위로 가져갈 수 있도록 그 배합비를 조절할 수 있다. 그 배합비의 일례를 아래 표 3에 제시한다.The Al-CaO flux used in the present invention may be composed of Al and CaO as the main components, and the mixing ratio of Al and CaO in the flux may be 1.5 kg or less per molten molten iron to bring the basicity and oxidation degree of molten iron slag to the desired range. Can be adjusted. An example of the compounding ratio is shown in Table 3 below.

Al-CaO계 플럭스(중량%)Al-CaO flux (wt%) AlAl CaOCaO Al2O3 Al 2 O 3 SiO2 SiO 2 Fe2O3 Fe 2 O 3 ≥40≥40 20∼3020-30 ≤5.0≤5.0 ≤10.0≤10.0 1.01.0

본 발명에 따라 Al-CaO계 플럭스를 투입하는데, 그 투입시점을 탈류제의 투입과 동시에 할 수도 있으나, 가장 바람직하게는 탈류제의 투입전에 하는 것이다. 이는 Al-CaO계 플럭스의 투입에 의한 슬래그 개질 즉, 슬래그의 산화도를 낮추고 염기도를 높이는 것이 빠르면 빠를수록 탈류반응효율이 향상되기 때문이다.According to the present invention, the Al-CaO-based flux is added, but the input time may be simultaneously with the addition of the desorbent, but most preferably before the addition of the desorbent. This is because the faster the slag reforming by the addition of the Al-CaO flux, that is, the lower the oxidation degree of slag and the higher the basicity, the faster the degassing reaction efficiency.

Al-CaO계 플럭스의 투입량은 용선톤당 1.0∼1.5kg으로 하는 것이 바람직한데, 그 이유는 적어도 용선톤당 1.0kg이상 투입하여야 용선슬래그의 개질이 가능하며, 1.5kg을 초과하면 슬래그의 개질은 충분하나 산화도의 감소폭이 작고 또한, 상대적으로 용선의 온도강하폭이 커져서 탈류율 저하요인이 될 수 있다.The amount of Al-CaO flux is preferably 1.0 to 1.5 kg per ton of molten iron. The reason is that at least 1.0 kg per ton of molten iron can be used to reform molten iron slag. The decrease in the degree of oxidation is small, and the temperature drop of the molten iron is relatively large, which may be a cause of deflow rate reduction.

상기와 같이, Al-CaO계 플럭스를 적용하여 용선슬래그의 산화도를 3.5%이하, 염기도를 1.2이상으로 확보하는 것이 탈류효율측면에서 유리하다.As described above, it is advantageous in terms of deflow efficiency to ensure the oxidation degree of molten iron slag is 3.5% or less and the basicity is 1.2 or more by applying Al-CaO flux.

이하, 본 발명을 실시예를 통하여 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.

[실시예 1]Example 1

표 4의 고로에서 출선한 용선에 Al-CaO플럭스를 투입한 직후 CaC2탈류제를 투입하여 탈류처리한 다음, 탈류효율과 함께 탈류시 온도하락을 조사하여 그 결과를 표 5에 나타내었다.Immediately after the Al-CaO flux was added to the molten iron drawn from the blast furnace of Table 4, the CaC 2 desorbent was added to the degassing treatment, and the temperature drop during dehydration with the degassing efficiency was investigated and the results are shown in Table 5.

용선성분(중량%)Molten iron component (wt%) 온도(℃)Temperature (℃) CC SiSi MnMn PP SS 4.0∼4.54.0 to 4.5 0.25∼1.000.25-1.00 0.25∼0.450.25 to 0.45 0.090∼0.1100.090-0.110 0.015∼0.0500.015 to 0.050 1350∼14501350-1450

구분division 고로탈규제투입량(kg/용선-톤)Blast furnace deregulation dose (kg / melt-ton) 플럭스투입량(kg/용선-톤)Flux input (kg / melting-ton) CaC2투입량(kg/용선-톤)CaC 2 input (kg / melting-ton) [S](ppm)[S] (ppm) 탈류시온도하락(℃)Temperature drop during dehydration (℃) 탈류반응효율(K')Deflow Reaction Efficiency (K ') 탈류전Before dehydration 탈류후After dehydration 실시예1Example 1 9.59.5 00 5.285.28 220220 6262 1818 0.2400.240 실시예2Example 2 11.011.0 0.50.5 4.224.22 210210 5555 2020 0.3180.318 실시예3Example 3 10.210.2 1.01.0 4.134.13 260260 3939 2323 0.4590.459 실시예4Example 4 11.511.5 1.51.5 4.154.15 270270 4343 2626 0.4430.443 실시예5Example 5 10.910.9 2.02.0 4.334.33 220220 4848 2828 0.3520.352 실시예6Example 6 9.99.9 2.52.5 4.204.20 190190 5151 3333 0.3130.313

표 5에서 알 수 있듯이, 동일한 탈류제를 투입한 경우, 탈류반응효율은 플럭스 투입량이 용선톤당 1.0∼1.5kg일 때 가장 우수하게 나타났다. 이를 그래프로 나타내면 도 4와 같다. 도 5에 나타난 바와 같이, 플럭스량이 증가할수록 용선슬래그의 산화도는 감소하고, 염기도는 증가함을 알 수 있다.As can be seen from Table 5, when the same desorbent is added, the dehydration reaction efficiency is most excellent when the flux input is 1.0 ~ 1.5kg per molten ton. This is shown in a graph as shown in FIG. As shown in Figure 5, it can be seen that as the amount of flux increases, the degree of oxidation of the molten iron slag decreases, and the basicity increases.

한편, 도 6에는 Al-CaO플럭스 투입시점에 따른 탈류반응효율이 나타내었는데, 탈류처리하기전에 Al-CaO플럭스를 투입하는 것이 탈류반응효율이 가장 높게 나타났다.On the other hand, Figure 6 shows the dehydration reaction efficiency according to the time of Al-CaO flux input, the Al-CaO flux was added before the desulfurization treatment was the highest.

상술한 바와 같이, 본 발명에 따라 Al-CaO계 플럭스 용선탈류전에 투입하면 탈류반응효율을 최적화할 수 있으며, 탈류제 원단위 저감을 통한 탈류시간 감소, 탈류후 안정된 [S]수준을 확보하여 전로 이후 공정에서 조업부하를 경감시킬 수 있는 유용한 효과가 있다.As described above, according to the present invention, if the Al-CaO-based flux molten iron before degassing can be optimized, the dehydration reaction efficiency can be optimized, and the desulfurization time can be reduced by reducing the desorbent unit, and a stable [S] level after dehydration is ensured. There is a useful effect to reduce the operating load in the process.

Claims (2)

래들에 수선된 탈규용선에 탈류제를 투입하여 탈류처리하는 용선의 예비처리방법에 있어서,In the method of pretreatment of molten iron which is deflowed by injecting a desorbent into the deregulated molten iron repaired to the ladle, 상기 탈류제의 투입전에 Al-CaO계 플럭스를 용선슬래그의 상부에 용선톤당 1.0∼1.5kg 투입하여 상기 용선 슬래그의 산화도를 3.5%이하, 염기도를 1.2이상으로 확보하는 것을 포함하여 이루어짐을 특징으로 하는 예비처리공정에서 탈규용선의 탈류효율증대방법.1.0-1.5 kg per ton of molten Al-CaO flux in the upper part of the molten iron slag prior to the addition of the desorbing agent to ensure that the oxidation degree of the molten iron slag is 3.5% or less and the basicity is 1.2 or more. Method for increasing degassing efficiency of de-silicone vessel in the pretreatment process. 제1항에 있어서, 상기 Al-CaO계 플럭스는 CaO가 20∼30중량%이고, 나머지 주성분이 Al임을 특징으로 하는 예비처리공정에서 탈규용선의 탈류효율증대방법.The method of claim 1, wherein the Al-CaO flux has a CaO of 20 to 30% by weight and the remaining main component is Al.
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KR20030009905A (en) * 2001-07-24 2003-02-05 심근섭 Method of Manufacturing a Ceramic Ware Utilizing the Screen Printing
KR100775240B1 (en) * 2001-06-15 2007-11-12 주식회사 포스코 Hot metal pretreatment for improving desulfurizing efficiency
KR100833268B1 (en) * 2006-12-28 2008-05-28 주식회사 포스코 Desulphurization method of sulfur in hot metal using slag of pre-treating pig iron

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GB2118209B (en) * 1982-02-12 1986-06-04 Showa Denko Kk Refining agent of molten metal and methods for producing the same
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JPH05222425A (en) * 1992-02-17 1993-08-31 Nippon Steel Corp Method for treating desulfurization of molten iron and desulfurized slag by calcium aluminate
JP3733689B2 (en) * 1997-03-26 2006-01-11 Ｊｆｅスチール株式会社 Hot metal desulfurization method
KR100328060B1 (en) * 1997-12-11 2002-05-13 이구택 A method for desulfurizing extremely low carbon low sulfurmelt in steel making
KR100336859B1 (en) * 1997-12-16 2002-10-09 주식회사 포스코 Control method of converter slag

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100775240B1 (en) * 2001-06-15 2007-11-12 주식회사 포스코 Hot metal pretreatment for improving desulfurizing efficiency
KR20030009905A (en) * 2001-07-24 2003-02-05 심근섭 Method of Manufacturing a Ceramic Ware Utilizing the Screen Printing
KR100833268B1 (en) * 2006-12-28 2008-05-28 주식회사 포스코 Desulphurization method of sulfur in hot metal using slag of pre-treating pig iron

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