KR100593685B1 - Seleclive Reduclion Method of BOF Slages - Google Patents

Seleclive Reduclion Method of BOF Slages Download PDF

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KR100593685B1
KR100593685B1 KR1019990063348A KR19990063348A KR100593685B1 KR 100593685 B1 KR100593685 B1 KR 100593685B1 KR 1019990063348 A KR1019990063348 A KR 1019990063348A KR 19990063348 A KR19990063348 A KR 19990063348A KR 100593685 B1 KR100593685 B1 KR 100593685B1
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slag
phosphorus
caf
reducing
molten iron
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KR20010060890A (en
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서성모
임창희
허기행
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주식회사 포스코
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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
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; 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
    • 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
    • C21C5/36—Processes yielding slags of special composition
    • 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
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising
    • C21C7/0645—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)
  • Manufacturing & Machinery (AREA)
  • 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

본 발명은 전로슬래그중 유가금속인 Fe를 회수하는 방법에서 환원슬래그중 P2O5를 회수하는 과정에서 환원슬래그중 P2O5를 슬래그중에 최대로 잔류시키고 용철만을 회수하는 환원방법에 관한 것으로, 코올(Coal)을 환원제로 하여 환원하는 종래방법에 CaFe의 첨가에 따른 슬래그의 융점을 낮추어 인의 환원반응을 최대한 억제하여 슬래그중 잔류인의 농도를 최대로 하며 용철중 잔류인을 최소로하여 주는 것으로써, 구성은 잔류슬래그를 코올(Coal)을 환원제로 하여 환원하는 방법에 있어서, 슬래그에 CaFe 8-20중량% 첨가하여 슬래그중 CaO/CaF2의 비가 2.6~5이하로 제어하여 환원하는 전로슬래그중 (T Fe)의 선택환원법에 관한 것이다.The present invention relates to a method of recovering Fe, a valuable metal in converter slag, in the process of recovering P 2 O 5 from the reducing slag to the maximum remaining P 2 O 5 in the slag and recovering only molten iron. , By reducing the slag melting point due to the addition of CaFe in the conventional method of reducing with Coal as a reducing agent to suppress the reduction reaction of phosphorus to maximize the concentration of residual phosphorus in slag and minimize the residual phosphorus in molten iron In the method for reducing residual slag by using Coal as a reducing agent, a converter for reducing by controlling the ratio of CaO / CaF 2 in slag by adding 8-20% by weight of CaFe to the slag and controlling the ratio of CaO / CaF 2 in the slag The selective reduction method of (T Fe) in slag.

염기도, 환원제, 슬래그, 코올(Coal)Basicity, Reducing Agent, Slag, Coal

Description

전로슬래그중의 선택환원법{Seleclive Reduclion Method of BOF Slages}Selective Reduclion Method of BOF Slages

본 발명은 전로슬래그중 (T Fe: Total Fe)의 선택환원법에 관한 것으로 상세하게는 전로슬래그중 유가금속인 Fe를 회수하는 과정에서 환원슬래그중 P2O5를 슬래그중에 최대로 잔류시키고 용철만을 회수하는 환원방법에 관한 것이다.The present invention relates to a selective reduction method of (T Fe: Total Fe) in the converter slag. Specifically, in the process of recovering Fe, a valuable metal in the converter slag, P 2 O 5 in the reducing slag remains in the slag to the maximum and molten iron alone. It relates to a reduction method for recovery.

일반적으로 전로작업시 생성되는 전로슬래그 성분은 다음표와 같다.In general, converter slag components generated during converter work are shown in the following table.

T FeT Fe CaOCaO SiO2 SiO 2 Al2O3 Al 2 O 3 P2O5 P 2 O 5 TiO2 TiO 2 SS 36.036.0 29.029.0 10.310.3 3.03.0 1.451.45 1.31.3 1.451.45

상기표에서 T Fe는 환원시 Fe로 회수되어 새로운 철원으로 사용되며 이러한 Fe 회수방법에 관한 특허는 이미 공개되어 있다.In the above table, T Fe is recovered as Fe and used as a new iron source, and a patent on such a method for recovering Fe is already disclosed.

그러나 종래기술은 전로슬래그중 용철을 회수하는 것을 목적으로 하며 회수된 용철에는 다량의 인이 포함되어 용철의 재사용시 포함된 인을 제거하기 위한 탈인처리를 반드시 거쳐야 하는 문제가 있었다. However, the prior art aims to recover molten iron in the converter slag, and the recovered molten iron includes a large amount of phosphorus, which has to undergo a dephosphorization treatment to remove phosphorus contained in reuse of molten iron.

일반적으로 종래방법에 의해 전로슬래그로부터 회수되는 용철중에는 원래 전로슬래그에 함유되어 있는 인의 약 40∼60%에 달하는 것으로 알려져 있다.In general, molten iron recovered from converter slag by conventional methods is known to reach about 40 to 60% of the phosphorus originally contained in converter slag.

따라서 본 발명이 이루고자 하는 기술적과제는 상술한 문제점을 해소할 수 있도록 전로슬래그중 인의 환원시 환원된 인중 용철중에 흡수되는 인을 최소로하여 별도의 탈인작업이 없이 탈인된 용철을 얻을 수 있는 방법을 제공함을 기술적 과제로 한다. Accordingly, the technical problem to be achieved by the present invention is to minimize the phosphorus absorbed in the reduced phosphorus molten iron during the reduction of phosphorus in the converter slag so as to solve the above-described problem to obtain a dephosphorized molten iron without a separate dephosphorization work It is a technical task to provide.

상술한 기술적 과제를 성취시키기 위한 구성은 전로슬래그 환원방법에 있어서, 형석과 형석+CaO를 첨가제로 투입하여 T Fe(Total Fe)는 감소되나 P의 환원을 억제하고 환원된 인은 가스로 대기중에 방출시켜 용철중에 환원된 인의 흡수를 최소화 시키는 것으로 전로슬래그를 코올(Coal)을 환원제로하여 환원하는 과정에서 CaF2를 8∼20중량% 첨가하여 슬래그중 (CaO)/(CaF2)의 비를 2.6~5 이하로 하여 환원하는 것으로 구성된다.
슬래그중 CaF2 가 설정범위 이상으로 과도하게 투입되어 (CaO)/(CaF2)의 비가 2.6이하로 되는 경우 슬래그의 유동성이 현저하게 개선되어 전로슬래그로부터 인성분이 용철중으로 급격하게 들어와 용존되며, CaF2가 소량으로 투입되어 (CaO)/(CaF2)의 비가 5 이상으로의 경우에는 CaF2 미투입의 경우와 큰차이가 없으므로 (CaO)/(CaF2)의 비를 2.6~5 이하로 설정한다.
참고로 본 발명에서 슬래그중 잔류인은 슬래그에 인이 환원되지 않고 남아있는 경우를 나타내고, 기화제거인은 기화되어 대기중으로 날라가는 인을 나타내며, 용철중 인은 용융된 철중에 환원되어 남아있는 인을 의미한다.In order to achieve the above technical problem, in the converter slag reduction method, fluorite and fluorspar + CaO are added as additives, T Fe (Total Fe) is reduced, but the reduction of P is suppressed and the reduced phosphorus is gas in the air. In order to minimize the absorption of phosphorus reduced in molten iron, the ratio of (CaO) / (CaF 2 ) in the slag is reduced by adding 8 to 20% by weight of CaF 2 in the process of reducing the converter slag with Coal as the reducing agent. It consists of reducing to 2.6-5 or less.
If the CaF 2 in the slag is excessively added beyond the set range and the ratio of (CaO) / (CaF 2 ) is less than 2.6, the fluidity of the slag is remarkably improved and the phosphorus component rapidly enters molten iron from the converter slag and dissolves. 2 is added in small amounts When the ratio of (CaO) / (CaF 2 ) is 5 or more, there is no significant difference from that of no CaF 2 addition. The ratio of (CaO) / (CaF 2 ) is set to 2.6 to 5 or less.
For reference, in the present invention, the residual phosphorus in the slag represents a case where phosphorus is not reduced in the slag, the degassing phosphorus represents phosphorus which is vaporized and blown into the atmosphere, and phosphorus in molten iron is reduced in molten iron. Means.

이하 상세히 설명하면 다음과 같다.Hereinafter will be described in detail.

전로슬래그중 인은 P2O5의 형태로 존재하며 환원제 탄소에 의한 환원반응은 다음과 같다.Phosphorus in the converter slag exists in the form of P 2 O 5 and the reduction reaction by the reducing agent carbon is as follows.

P2O5+5C = P2+5COP 2 O 5 + 5C = P 2 + 5CO

P2 = 2PP 2 = 2P

따라서 본발명의 구성은 환원반응을 억제함과 동시에 환원반응에 P2가스가 용철에 흡수되지 않고 대기로 최대 배출되도록 하여 용철중에 환원된 인의 흡수를 최소화 시키는 것으로 전로슬래그를 코올(Coal)을 환원제로 하여 환원하는 과정에서 슬래그중 (CaO)/(CaF2)의 비를 2.6~5이하가 되도록 형석이나 CaF2를 첨가하는 것이다.Therefore, the composition of the present invention minimizes the absorption of reduced phosphorus in molten iron by suppressing the reduction reaction and allowing P 2 gas to be discharged to the atmosphere instead of being absorbed by molten iron. Fluorite or CaF 2 is added so that the ratio of (CaO) / (CaF 2 ) in the slag is 2.6 to 5 or less in the process of reduction.

이하 실시예에 의해 서술하면 다음과 같다.Described by the following examples are as follows.

실시예 1Example 1

유도용해로를 사용하여 실시하였으며 슬래그용체에 환원제로 코올(Coal)을 사용한 통상의 환원법과 CaF2를 10% 첨가하여 환원한 본 발명의 환원거동을 비교하였다.The reduction behavior of the present invention was performed by using an induction furnace and reducing the slag solution by adding 10% of CaF 2 and a conventional reduction method using a coal (Coal) as a reducing agent.

반응온도는 1550℃-1600℃ 구간에서 실시하였으며 반응시간은 표 1에서 보면 알 수 있듯이 50분에서 1시간 정도 처리한다.The reaction temperature was carried out in the 1550 ℃ -1600 ℃ section and the reaction time is treated in 50 minutes to 1 hour as can be seen in Table 1.

표 1a는 CaF2 첨가시(T Fe : Total Fe)농도변화를 통상의 방법과 비교한 그래프이고,Table 1a is a graph comparing the change in concentration when CaF 2 is added (T Fe: Total Fe) with a conventional method,

표 1b는 CaF2 첨가시(P2O5)농도 변화를 통상의 방법과 비교한 그래프이다.Table 1b is a graph comparing the change in concentration when adding CaF 2 (P 2 O 5 ) to a conventional method.

표 1의 그래프에서 알 수 있듯이 통상의 경우 T Fe가 3∼5중량%에서 P의 환원이 급격히 진행되는 반면 CaF2를 투입한 발명의 경우 P의 환원속도가 현저히 낮아짐을 알 수 있어 CaF2의 첨가시 T Fe는 감소하나 P의 환원을 억제함을 알 수 있다.If the normal as can be seen from the graph shown in Table 1, while the T Fe progress at 3-5% by weight is rapidly reduced in the case of P In the invention a CaF 2 it can be seen that the lowered significantly reduced rate of P of CaF 2 It can be seen that the addition of T Fe decreases but suppresses the reduction of P.

Figure 111999018370470-pat00001
Figure 111999018370470-pat00001

Figure 111999018370470-pat00002
Figure 111999018370470-pat00002

실시예 2Example 2

실시예 2는 실시예 1에서 얻은 인의 매스밸런스(Mass balance) 및 실시예 1과 동일하게 실시하였으며 환원시 가스취입에 의한 방법과 가스미취입에 의한 방법에 따른 인의 매스 밸런스(Mass balance)를 조사하여 비교한 결과 표 2와 같은 결과를 얻었다.Example 2 was carried out in the same manner as the mass balance of the phosphorus obtained in Example 1 and Example 1, by examining the mass balance of phosphorus according to the method by the gas blowing and the non-gas blowing during reduction As a result of the comparison, the results shown in Table 2 were obtained.

표 2에 도시된 바와 같이 본 발명인 CaF2를 첨가한 경우 슬래그중에 잔류하는 인의 양이 통상의 방법에 비해 2배이상 잔류함을 알 수 있으며, 기화되어 제거되는 양은 거의 동등한 수준을 보여줌에 반해 용철중에 잔존하는 인의 양은 통상의 방법에 비해 1/2 수준임을 알 수 있다.As shown in Table 2, the addition of CaF 2 of the present invention shows that the amount of phosphorus remaining in the slag is more than two times that of the conventional method, and the amount of vaporized and removed shows almost the same level. It can be seen that the amount of phosphorus remaining in the level is 1/2 level compared with the conventional method.

이는 CaF2 첨가에 의해 슬래그내 인의 안정성을 높여 인의 환원속도를 늦추어 환원된 용철이 슬래그중 잔류할 때 인이 흡수되는 것이 줄어드는 이유로 설명되며, 이러한 차이를 환원반응시 가스취입을 하지 않는 경우와 비교하면 CaF2를 첨가하고 가스 미취입시 인의 환원거동이 거의 진행되지 않음으로 알 수 있다.This is explained by the increase of stability of phosphorus in slag by adding CaF 2, which slows down the reduction rate of phosphorus and reduces the absorption of phosphorus when the reduced molten iron remains in the slag. This difference is compared with the case where no gas injection is performed during the reduction reaction. If CaF 2 is added, the reduction behavior of phosphorus hardly proceeds when gas is not blown.

따라서 CaF2의 첨가와 가스의 미취입 방법은 슬래그내 인의 안정성을 도모하여 인의 환원속도를 늦추어 환원된 용철이 슬래그중 잔류시 상대적으로 인의 흡수가 적어지는 것을 알 수 있다.Therefore, the addition of CaF 2 and the gas blowing method can improve the stability of phosphorus in the slag, slow down the reduction rate of phosphorus, and it can be seen that the absorption of phosphorus is relatively reduced when the reduced molten iron remains in the slag.

Figure 111999018370470-pat00003
Figure 111999018370470-pat00003

실시예 3Example 3

실시예 3은 실시예 1과 동일조건에서 실시하였으며 CaF2와 CaO의 첨가량을 조절하여 CaO/CaF2 비에 따른 인의 제거양상을 조사하여 표 3에 도시하였다.Example 3 was carried out under the same conditions as in Example 1, by controlling the addition amount of CaF 2 and CaO to investigate the removal pattern of phosphorus according to the CaO / CaF 2 ratio shown in Table 3.

표 3에서 알 수 있듯이 대체로 CaO/CaF2가 낮아짐에 따라 슬래그중 잔류인이 증가하며 CaO/CaF2가 2.6 이상이 되면 슬래그중 잔류인이 감소하며 제거되는 인의 양이 일정하게 유지됨을 알 수 있다.As can be seen from Table 3, as CaO / CaF 2 is lowered, the residual phosphorus in slag increases, and when CaO / CaF 2 is 2.6 or more, the residual phosphorus in slag decreases and the amount of phosphorus removed remains constant. .

이는 CaO/CaF2가 2.6 이상에서는 슬래그중 인의 안정성 향상에 영향을 미치지 못하며 슬래그에 유동성을 증가시켜 환원속도를 높임으로 용철로의 인의 흡수를 증가시키게 되어 용철내 인의 함유량이 증가되는 것을 알 수 있다.This does not affect the stability improvement of phosphorus in slag when CaO / CaF 2 is 2.6 or higher, and it is found that the phosphorus content in molten iron increases because the absorption of phosphorus into molten iron increases by increasing the reduction rate by increasing fluidity in slag. .

따라서 인의 환원시 CaO/CaF2가 2.6~5이하로 유지하는 것이 필요함을 알 수 있다.Therefore, it can be seen that it is necessary to maintain the CaO / CaF 2 is 2.6 ~ 5 or less during the reduction of phosphorus.

Figure 111999018370470-pat00004
Figure 111999018370470-pat00004

표2와 표3의 하나의 막대 그래프에서 맨위가 슬래그중 잔류인, 그 아래가 기화제거인, 그 아래가 용철중인을 나타내는 것이다. 즉, x축에 가까운 부분이 용철중 인을 나타낸다.
실시예 4는 CaO/CaF2을 2.6으로 하여 코올(Coal)을 환원제로 사용한후 환원된 용철의 성분과 통상적인 방법에 의한 용철의 성분을 조사하여 비교하였다.In one bar graph of Tables 2 and 3, the top represents residual in slag, the bottom degassing, and the bottom is molten. That is, the part near the x-axis shows phosphorus in molten iron.
In Example 4, CaO / CaF 2 was set to 2.6, and then, by using Coal as a reducing agent, the components of the reduced molten iron were compared with those of the molten iron by a conventional method.

물론 기타 조건은 실시예 1과 동일하게 실시하였다.Of course, other conditions were performed similarly to Example 1.

아래 표4의 실시결과에서 도시된 바와 같이 용철중 인의 함유량이 통상방법에 비해 월등히 낮아진 것을 알 수 있게 한다.As shown in the results of Table 4 below, it can be seen that the content of phosphorus in the molten iron is much lower than in the conventional method.

Figure 111999018370470-pat00005
Figure 111999018370470-pat00005

본 발명의 효과로는 전로슬래그중 용철을 회수하는 과정에서 회수된 용철중에 인을 최소로하여 회수함으로써 종래 회수된 용철중 인을 제거하기 위한 탈인작업을 거쳐야 하는 번거로움을 피하며 탈인공정의 생략에 따른 원가를 감소시키는 효과가 있다.The effect of the present invention is to minimize the phosphorus in the recovered molten iron in the process of recovering molten iron in the converter slag to avoid the need to go through the dephosphorization work to remove the phosphorus in the conventionally recovered molten iron, eliminating the dephosphorization process This has the effect of reducing the cost.

Claims (1)

전로슬래그를 코올(Coal)을 환원제로하여, Fe를 환원하는 방법에 있어서,In the method of reducing the Fe by using the converter slag as a reducing agent (Coal), 반응온도는 1550℃-1600℃ 구간, 반응시간 50분~1시간 정도 실시하고, 전체 슬래그량에서 CaF2를 8∼20중량% 첨가하여 슬래그중 CaO/CaF2의 비가 2.6~5이하 범위로 제어하여 환원하는 전로슬래그중(T Fe)의 선택환원법.The reaction temperature is 1550 ℃ -1600 ℃, reaction time is about 50 minutes ~ 1 hour, and 8 ~ 20 wt% of CaF 2 is added to the total slag to control the CaO / CaF 2 ratio in the slag within 2.6 ~ 5 Selective reduction method of converter slag (T Fe) to be reduced by
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61213309A (en) * 1985-03-19 1986-09-22 Nippon Steel Corp Manufacture of flux for refining using molten pig iron dephosphorization slag as starting material
JPS6213541A (en) * 1985-07-11 1987-01-22 Nippon Steel Corp Method for recovering valuable metal from converter slag
JPS6455318A (en) * 1987-08-25 1989-03-02 Nippon Kokan Kk Method for refining in converter
KR970043110A (en) * 1995-12-30 1997-07-26 김종진 Method of reforming steelmaking slag

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61213309A (en) * 1985-03-19 1986-09-22 Nippon Steel Corp Manufacture of flux for refining using molten pig iron dephosphorization slag as starting material
JPS6213541A (en) * 1985-07-11 1987-01-22 Nippon Steel Corp Method for recovering valuable metal from converter slag
JPS6455318A (en) * 1987-08-25 1989-03-02 Nippon Kokan Kk Method for refining in converter
KR970043110A (en) * 1995-12-30 1997-07-26 김종진 Method of reforming steelmaking slag

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