KR920005611B1 - Prevention of eruption of stainless steel slag - Google Patents
Prevention of eruption of stainless steel slag Download PDFInfo
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- KR920005611B1 KR920005611B1 KR1019890020002A KR890020002A KR920005611B1 KR 920005611 B1 KR920005611 B1 KR 920005611B1 KR 1019890020002 A KR1019890020002 A KR 1019890020002A KR 890020002 A KR890020002 A KR 890020002A KR 920005611 B1 KR920005611 B1 KR 920005611B1
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- slag
- differentiation
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- stainless steel
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- 239000002893 slag Substances 0.000 title claims description 39
- 229910001220 stainless steel Inorganic materials 0.000 title claims description 10
- 239000010935 stainless steel Substances 0.000 title claims description 10
- 230000002265 prevention Effects 0.000 title description 2
- 238000000034 method Methods 0.000 claims description 18
- 230000004069 differentiation Effects 0.000 claims description 17
- 238000007670 refining Methods 0.000 claims description 14
- 229910004298 SiO 2 Inorganic materials 0.000 description 12
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 12
- 239000004327 boric acid Substances 0.000 description 12
- 230000009466 transformation Effects 0.000 description 10
- 239000003795 chemical substances by application Substances 0.000 description 7
- 230000009467 reduction Effects 0.000 description 7
- 230000003540 anti-differentiation Effects 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 5
- 229910000423 chromium oxide Inorganic materials 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000004575 stone Substances 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000005261 decarburization Methods 0.000 description 2
- 238000006477 desulfuration reaction Methods 0.000 description 2
- 230000023556 desulfurization Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 235000019738 Limestone Nutrition 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910021540 colemanite Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
Classifications
-
- 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
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/54—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
- 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
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
내용 없음.No content.
Description
본 발명은 스테인레스강 정련시 발생하는 슬래그의 분화를 방지하기 위한 스테인레스강 슬래그의 분화방지방법에 관한 것이다. 일반적으로 스테인레스강 정련시에는 산소 취입에 의한 탈탄반응 종료후 탈탄반응시 생성된 크롬 산화물의 환원을 실시하게 되는데 이때 슬래그의 염기도는 환원 효율의 향상을 위해 1.8-2.5범위로 조절하게 된다. 그런데 환원 종료후의 슬래그 염기도가 1.6이상인 경우, 슬래그의 냉각 과정중 미세한 분으로 본화하여 공장 내외의 환경을 오염시킬 뿐만 아니라 슬래그의 재활용에도 큰 장애 요인이 된다. 특히, 환경 오염에 대한 규제가 더욱 엄격해 지고 있기 때문에 스테인레스강 슬래그의 분화방지가 더욱더 요구되고 있다. 환원 종료후의 스테인레스강 슬래그는 염기도가 2부근에서 조절되기 때문에 슬래그의 대부분이 2CaO·SiO2로 구성되고 있고 기타 금속 산화물은 미량에 불과하다.The present invention relates to a method for preventing differentiation of stainless steel slag for preventing differentiation of slag generated during stainless steel refining. In general, in the refining of stainless steel, the reduction of the chromium oxide generated during the decarburization reaction after the decarburization reaction by oxygen injection is performed, and the basicity of the slag is controlled to be in the range of 1.8 to 2.5 to improve the reduction efficiency. However, when the slag basicity after the reduction is 1.6 or more, it becomes a fine obstacle during the cooling process of the slag to pollute the environment inside and outside the factory, and also becomes a major obstacle to recycling the slag. In particular, due to stricter regulations on environmental pollution, prevention of differentiation of stainless steel slag is required. Since the basicity of stainless steel slag after the reduction is reduced to around 2, most of the slag is composed of 2CaO · SiO 2 and only a small amount of other metal oxides.
이러한 슬래그의 분화현상은 슬래그의 냉각 과정에서 2CaO·SiO2의 결정 변태에 기인하는 것으로 알려져 있다. 즉 2CaO·SiO2는 온도에 따라 α,α',β, γ의 상(phase)으로 존재할 수 있는데 이들의 변태 과정 및 온도는 다음과 같다.The differentiation of slag is known to be due to the crystal transformation of 2CaO.SiO 2 during the slag cooling process. That is, 2CaO.SiO 2 may exist as phases of α, α ', β, and γ according to temperature, and their transformation process and temperature are as follows.
통상적인 대기중 냉각에 의해서는 α상→α'상→γ상의 변태 과정을 거치지만 특정 조건하에서 α상→β상으로의 변태를 유도할 수가 있다. 또 상기 각 상들의 밀도(g/Cm3)는 α상 : 3.07, α'상 : 3.31, γ상 : 2.97, β상 : 3.28이다.Normal air cooling undergoes the transformation process of the α phase → α ′ phase → γ phase, but under certain conditions, the transformation from the α phase to the β phase can be induced. In addition, the density (g / Cm 3 ) of each phase is α phase: 3.07, α 'phase: 3.31, γ phase: 2.97, β phase: 3.28.
상기 변태과정에서 α상→α'상으로의 변태시에는 체적 수축이 일어나기 때문에 문제가 되지 않지만 α상→γ상으로 변태시에는 체적 팽창이 일어나게 되고 정량적으로는 약 14%정도가 되어 냉각 과정중 슬래그가 분화하게 된다. 그러나, α'상→β상으로 변태시에는 체적 변화가 거의 일어나지 않기 때문에 α'상→β상으로의 변태를 촉진시킴으로써 분화 현상을 방지할 수 있다.This is not a problem because the volumetric contraction occurs during the transformation from the α phase to the α 'phase in the transformation process, but the volume expansion occurs during the transformation from the α phase to the γ phase and quantitatively becomes about 14% during the cooling process. Slag will erupt. However, since the volume change hardly occurs in the transformation from the α 'phase to the β phase, the differentiation phenomenon can be prevented by promoting the transformation from the α' phase to the β phase.
종래의 슬래그 분화 방지제 및 분화 방법으로는Conventional slag inhibitors and differentiation methods
1) SiO2첨가에 의한 슬래그 성분 조성법(슬래그 용기내 투입)1) Slag component composition method by adding SiO 2 (Into slag container)
2) P2O5첨가법(슬래그 용기내 투입)2) P 2 O 5 addition method (into the slag container)
3) 붕산(B2O3·nH2O)첨가법(슬래그 용기 또는 반응 용기내 직접 투입) 및3) boric acid (B 2 O 3 · nH 2 O) addition method (directly into the slag vessel or reaction vessel) and
4) 급속냉각법이 알려져 있다.4) Rapid cooling is known.
상기 방법 1)은 슬래그중으로 SiO2를 첨가함으로써 슬래그의 주된 상을 슬래그의 분화현상이 일어나지않는 CaO·SiO2로 유도하고자 한 것이다. 그러나 이때 필요한 SiO2량은 슬래그 중량의 20% 이상이 요구되고 완전한 혼합물을 얻기 곤란하며 정련용기내로 첨가하는 것은 염기도 조절때문에 곤란한 문제가 있다. 또한, 방법 2) 및 3)은 소량 첨가만으로도 분화 방지 효과가 있다고 알려져 있으나, 배재시 슬래그의 낙하력에의한 교반을 기대하기 때문에 균일한 혼합을 얻기가 곤란할 뿐만 아니라 정련 용기내에 잔류 또는 출강구 주위에 부착한 슬래그의 분화는 방지하기가 곤란한 문제가 있다. 또한, 상기 방법 4)의 경우에는 냉각속도가 400-500℃/분 이상이 요구되기 때문에 실용성이 없다. 특히, 상기 방법 2)의 P2O5를 정련 용기내로 첨가하는 것은 정련용기내에서 P2O5의 환원에 의해 용강중 [P]함량을 높이기 때문에 곤란한 문제가 있으며, 또한, 상기 방법 3)의 붕산을 정련 용기내로 첨가하는 방법이 제시되고 있으나 붕산은 매우 고가일 뿐아니라 융점(450-465℃)이 매우 낮아 상당한 손실이 일어나는 문제가 있다. 따라서, 본 발명은 스테인레스강 정련 용기내에 분화방지제로서 회붕석을 첨가함으로서 스테인레스강 정련시에 발생하는 모든 슬래그의 분화를 분화방지제의 손실없이 경제적으로 방지하고자 하는데, 그 목적이 있다.Method 1) is to induce the main phase of the slag to CaO · SiO 2 without the slag differentiation by adding SiO 2 to the slag. However, the amount of SiO 2 required at this time requires more than 20% of the slag weight, and it is difficult to obtain a complete mixture. In addition, the methods 2) and 3) are known to have anti-differentiation effects even with a small amount of addition, but it is difficult to obtain uniform mixing because it is expected to stir due to the dropping force of slag during discharging, and it is difficult to obtain uniform mixing and remain in the refining vessel. Differentiation of the slag adhering to the surroundings has a problem that is difficult to prevent. In addition, in the case of the method 4), since the cooling rate is required to be 400-500 ° C / min or more, it is not practical. In particular, the addition of P 2 O 5 of the above-described method 2 into the refining vessel has a problem because it increases the [P] content in the molten steel by reduction of P 2 O 5 in the refining vessel. Although a method of adding boric acid into a refining vessel has been proposed, boric acid is not only very expensive but also has a very low melting point (450-465 ° C.), causing a significant loss. Accordingly, an object of the present invention is to economically prevent the differentiation of all slag generated during stainless steel refining without loss of the anti-differentiation agent by adding gray borosilicate as the anti-differentiation agent in the stainless steel refining vessel.
이하, 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail.
본 발명은 스테인레스 강의 정련시 슬래그중량에 대하여 1.0-5.0 중량%의 회붕석(2CaO·3B2O3·5H2O)을 정련용기 내에 투입하여 슬래그의 분화를 방지하는 방법에 관한 것이다.The present invention relates to a method for preventing the differentiation of slag by introducing 1.0-5.0% by weight of gray borosilicate (2CaO. 3B 2 O 3 .5H 2 O) to the refining vessel in the refining vessel.
이하, 상기 회붕석의 첨가이유와 성분범위의 한정이유에 대하여 설명한다. 회붕석은 융점이 약 1142°C인 물질로서 2CaO·3B2O3·5H2O의 화학 구조식으로 되어 있으며, 회붕석이 슬래그의 분화방지 역할을 하는것은 회붕석중의 B2O3가 2CaO·SiO2와 고용체를 형성하여 2CaO·SiO2의 γ상으로의 변태를 억제하기 때문이다. 또한, 회붕석은 B2O3와 CaO의 화합물로서 광물상태(Colemanite)로 존재하기 때문에 원료의 취급이 용이하고, 융점(1142℃)이 붕산 단독에 비하여 비교적 높기 때문에 제강온도인 1700℃부근에서 첨가해도 증발손실이 붕산 단일 물질보다는 작게된다.Hereinafter, the reason for addition of the gray borosilicate and the reason for limiting the component range will be described. Gray stone has a melting point of about 1142 ° C, and has a chemical structure of 2CaO · 3B 2 O 3 · 5H 2 O. The fact that gray stone is to prevent the differentiation of slag is that B 2 O 3 in gray stone is 2CaO · SiO 2 This is because a solid solution is formed to suppress transformation of 2CaOSiO 2 into the γ phase. In addition, gray borosilicate is a compound of B 2 O 3 and CaO, so it is present in the mineral state (Colemanite), so it is easy to handle raw materials, and the melting point (1142 ℃) is relatively higher than that of boric acid alone, so it is added near the steelmaking temperature of 1700 ℃. Even if the evaporation loss is smaller than the boric acid single material.
붕산과 회붕석에 대한 증발손실량을 보다 구체적으로 설명하기 위하여 본 발명자는 CaO : 18g, SiO2: 8g 및 무수붕산 : 4g을 혼합한 경우와, CaO : 15.85, SiO2: 8g 및 무수회붕석 : 6.15g을 혼합한 경우에 대하여 온도에 따른 붕산과 회붕석의 감소량을 B2O3의 감량으로 측정하고 그 결과를 하기 표 1에 나타내었다.In order to explain the evaporation loss amount to boric acid and gray boil in more detail, the present inventors have mixed CaO: 18g, SiO 2 : 8g and boric anhydride: 4g, CaO: 15.85, SiO 2 : 8g and anhydrous borosilicate: In the case of mixing 6.15g, the amount of reduction of boric acid and gray borestones with temperature was measured by the loss of B 2 O 3 and the results are shown in Table 1 below.
[표 1]TABLE 1
상기 표 1에 나타난 바와 같이, 붕산을 분화방지제로 첨가하는 경우에는 800℃에서도 B2O3중량기준으로 10% 이상의 중량감소가 일어나며 온도가 증가함에 따라 그 감소량은 증가하는 반면에, 회붕석을 분화방지제로 첨가하는 경우에는 1200℃에서도 B2O3중량기준으로 1% 이하의 감소를 나타냄을 알 수 있는데, 이는 실제적으로 분화방지제를 사용하는 온도인 1700℃정도에서 회붕석의 감소량은 붕산에 비하여 현저히 적다는것을 의미하는 것이다. 또한, 상기 회붕석은 B2O3가 CaO와 화합물을 이루고 있기 때문에 B2O3의 활량이 낮아 붕산 단독의 경우 보다도 고온에서 사용하기에 더욱 효과적이다. 또한 회붕석은 CaO를 일부 함유하고 있기 때문에 염기도 조절에 소요되는 CaO량을 회붕석에서 첨가되는 CaO량 만큼 절감하는 것이 가능하게 된다.As shown in Table 1, when boric acid is added as an anti-differentiation agent, a weight loss of 10% or more occurs at 800 ° C. based on the weight of B 2 O 3 , and the decrease increases with increasing temperature, while grayish limestone is used. When it is added as an anti-differentiating agent, it can be seen that a decrease of 1% or less based on the weight of B 2 O 3 even at 1200 ℃, which is actually reduced by about 1700 ºC, which is the temperature at which the anti-differentiating agent is used, compared to boric acid. That means a lot less. In addition, the seats hoebung B 2 O 3 is more effective for use at a high temperature than in the case of the sole, because the CaO forms as compound hwalryang of B 2 O 3 less acid. In addition, since gray lime contains a part of CaO, it is possible to reduce the amount of CaO required to adjust the basicity by the amount of CaO added from gray lime.
본 발명에서는 회붕석의 첨가량을 슬래그 중량에 대하여 1.0-5.0중량％로 한정한 것은 1.0 중량% 이하인 경우에는 2CaO·SiO2와 고용체를 이루는 B2O3양이 부족하여 분화방지의 효과가 없으며, 5.0 중량% 이상인 경우에는 회붕석의 첨가량이 과다하여 회붕석중의 B2O3가 산소공급원으로 작용하여 슬래그중 산소포텐셜(Potential)을 높이므로서 크롬산화물과 반응하는 Si과 결합하여 크롬 산화물의 환원효율을 저하시키기 때문이다.In the present invention, when the amount of gray borosilicate is limited to 1.0 to 5.0% by weight of slag, when the amount is 1.0% by weight or less, the amount of B 2 O 3 constituting 2CaO · SiO 2 and a solid solution is insufficient, thus preventing the effect of differentiation. If it is more than% by weight, the addition amount of gray borosilicate is excessive, and B 2 O 3 in gray borosilicate acts as an oxygen source to increase oxygen potential in slag, thereby combining with Si reacting with chromium oxide to reduce the reduction efficiency of chromium oxide. This is because it lowers.
이하, 실시예를 통하여 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail through examples.
[실시예]EXAMPLE
하기 표 2의 조성을 갖는 용강에 하기 표 3과 같이 붕산과 회붕석을 첨가하였으며, 이때 슬래그중의 크롬산화물은 12중량%로 첨가되고 반응후의 슬래그 염기도(CaO/SiO2)는 회붕석중의 CaO를 포함하여 2.4-2.6범위로 조절하였다. 상기 슬래그중 크롬 산화물의 산소를 완전히 제거할 수 있는 량의 Si를 슬래그와 혼합하여 1700℃에서 120분간 반응시킨 후 슬래그의 분화유무 빛 탈황율을 측정하고, 그 결과를 하기 표 4 및 표 3에 각각 나타내었다.To the molten steel having the composition shown in Table 2, boric acid and gray borosilicate were added as shown in Table 3 below, in which chromium oxide in slag was added at 12% by weight, and the slag basicity (CaO / SiO 2 ) after the reaction represented CaO in gray borosilicate. In the range of 2.4-2.6. The amount of Si that can completely remove the oxygen of the chromium oxide in the slag was mixed with the slag and reacted at 1700 ° C. for 120 minutes, and then the light desulfurization rate of the differentiation of the slag was measured, and the results are shown in Tables 4 and 3 below. Respectively.
[표 2]TABLE 2
[표 3]TABLE 3
[표 4]TABLE 4
상기 표 3 및 표 4에 나타난 바와 같이, 붕산을 첨가한 종래예와 회붕석을 첨가한 발명예(A, B, C)는 분화방지 효과면에서 동등하거나 우수함을 알 수 있으며, 비교예(1-2)는 발명예(A, B, C)보다는 분화방지 효과면에서는 우수하지만, 탈황효율이 떨어짐을 알 수 있다.As shown in Table 3 and Table 4, the conventional example with boric acid and the invention examples (A, B, C) with the addition of gray borosilicate can be seen that the equivalent or superior in the anti-differentiation effect, Comparative Example (1 -2) is better in terms of anti-differentiation effect than the invention examples (A, B, C), but it can be seen that the desulfurization efficiency is low.
상술한 바와 같이, 본 발명은 분화방지제로서 회붕석을 첨가하므로서 종래의 분화방지제인 붕산에 비해 고온에서의 B2O3의 증발 손실이 적음과 동시에, 슬래그분화방지의 효과가 있기 때문에 정련용기내에 직접 투입함으로써 정련시 발생하는 모든 슬래그의 분화를 방지하는데 효과가 있는 것이다.As described above, the present invention has a lower evaporation loss of B 2 O 3 at a higher temperature than boric acid, which is a conventional anti-differentiating agent, by adding gray borosilicate as an anti-differentiating agent, and has an effect of preventing slag differentiation in the refining vessel. It is effective to prevent the differentiation of all slag generated during refining by direct injection.
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| KR1019890020002A KR920005611B1 (en) | 1989-12-28 | 1989-12-28 | Prevention of eruption of stainless steel slag |
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| CN102719621A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Refining slag prepared from molten steel refining waste residues and method thereof |
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| CN102719621A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Refining slag prepared from molten steel refining waste residues and method thereof |
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