KR20000015192A - Surface heat insulating material of smelting furnace - Google Patents

Surface heat insulating material of smelting furnace Download PDF

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KR20000015192A
KR20000015192A KR1019980034964A KR19980034964A KR20000015192A KR 20000015192 A KR20000015192 A KR 20000015192A KR 1019980034964 A KR1019980034964 A KR 1019980034964A KR 19980034964 A KR19980034964 A KR 19980034964A KR 20000015192 A KR20000015192 A KR 20000015192A
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insulating material
smelting furnace
molten steel
heat insulating
pulp sludge
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KR1019980034964A
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Korean (ko)
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KR100265212B1 (en
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박대성
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박대성
주식회사 동림
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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
    • C21C7/005—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using exothermic reaction compositions
    • 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
    • C21C2200/00—Recycling of waste material

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

PURPOSE: Surface heat insulating material of smelting furnace preventing to carburize in smelting furnace different with existing carbonized chaff to heat conservation surface temperature of smelting furnace continuously rather than existing chemical heat insulating material by using waste pulp sludge. CONSTITUTION: Surface heat insulating material of smelting furnace to endurance heat conservation by forming powdered layer thickly on the upper is manufactured with 70-80% of waste pulp sludge containing SiO2 and Al2O3 as principal component as waste generated in paper-making plant as principal component of heat insulating material, 5-12 weight% of coke to endurance heat conservation of smelting furnace for long time rather than the existence of waste pulp sludge only by exothermic reaction with inputting in smelting furnace surface, 4-7% of burned lime(CaO) to control slag basicity of smelting furnace and use to binding agent, 2-5% of magnesia(MgO) to ascend coefficient of heat conduction by adding heat insulating material.

Description

용강표면보온재Molten steel surface insulation

본 발명은 용강의 표면보온재에 관한 것으로서, 보다 상세하게는 폐펄프슬러지를 이용한 용강표면보온재에 관한 것이다.The present invention relates to a surface insulating material of molten steel, and more particularly to a molten steel surface insulating material using waste pulp sludge.

일반적으로 용강의 표면보온재는 용강을 운반하는 레들이나 연주주조용 턴디쉬(tundish) 등에서 용강의 표면에 덮어 씌워 용강 정련 과정중 단열 및 보온과 더불어 대기에 의한 용강산화를 방지하기 위해 사용된다.In general, the surface insulating material of molten steel is used to cover the surface of the molten steel in a ladle carrying a molten steel or a tundish for performing casting, and to prevent the oxidation of the molten steel in the atmosphere along with insulation and insulation during the molten steel refining process.

통상 제강정련조업에 사용되는 용강표면보온재로는 자연산보온재와 화학적 보온재가 있다.The molten steel surface insulation materials commonly used in steelmaking refining operations include natural insulation and chemical insulation.

상기 자연산보온재의 대표적인 예로서, 벼껍질을 구어서 만든 탄화왕겨가 있다. 탄화왕겨는 그 주성분이 SiO2와 C로서 열전도율이 낮고 보온효과가 좋으며 탄소와 화합하여 CO가스를 발생하여 대기 산소를 차단하는 효과가 있음은 물론 값이 싸기 때문에 보온재로 많이 사용되어왔다. 그러나, 탄화왕겨를 보온재로 사용하는 경우 용강 표면에 탄화왕겨를 분산 투입하여 사용해야만 하므로 보온효과가 떨어지는 단점이 있다. 특히 가공용 강판에 소요되는 극저탄소강을 제조할 때는 탄화왕겨중의 탄소성분이 용강중으로 가탄되어 강재의 특성을 저하시키는 문제가 있다.As a representative example of the natural thermal insulation material is a charcoal chaff made by baking rice husk. The main components of charcoal chaff are SiO 2 and C, which have low thermal conductivity, good thermal insulation effect, and combine with carbon to generate CO gas to block atmospheric oxygen. However, in the case of using the charcoal chaff as a heat insulating material, since the chaff must be used by dispersing the charcoal chaff on the surface of the molten steel, there is a disadvantage that the insulation effect is low. In particular, when manufacturing the ultra-low carbon steel required for the steel sheet for processing, there is a problem in that the carbon component in the carbonized chaff is peat into the molten steel to reduce the characteristics of the steel.

한편, 상기 화학적 보온재의 대표적인 예로 SiO2계 또는 MgO계 보온재 등을 들 수 있다. 이중 일본 특개평8-33960호에는 CaO/Al2O3의 비가 0.5~1.0이고, MgO를 5%이상 30%미만, SiO2가 10%이하인 액상보온재에 CaO/Al2O3의 비가 0.5미만 또는 2.0을 초과한 중공소결체를 5~90%함유시킨 용강보온재가 개시되어 있다.On the other hand, a representative example of the chemical insulating material may be SiO 2 or MgO-based insulation. In Japanese Patent Laid-Open No. 8-33960, the ratio of CaO / Al 2 O 3 is 0.5 to 1.0, and the ratio of CaO / Al 2 O 3 is less than 0.5 to a liquid insulating material having MgO of 5% or more and less than 30% and SiO 2 or less. Or molten steel insulation containing 5 to 90% of the hollow sintered body exceeding 2.0 is disclosed.

그러나, 보통 SiO2계 보온재는 SiO2성분이 용강중의 Al과 반응하여 Al2O3개재물을 생성하는 문제가 있고, 상기 일본 특개평8-33960호와 같은 보온재는 용융점이 높은 MgO성분이 다량함유되어 용강표면에서 용해와 분해가 잘 안되고 이에 따라 용강 표면에 보온재가 균일하게 분산되지 못하여 보온이 미흡하고 용강을 2차산화시키는 등의 문제가 있다.However, in general, the SiO 2 type thermal insulation material has a problem in that the SiO 2 component reacts with Al in molten steel to generate Al 2 O 3 inclusions, and the thermal insulation material such as Japanese Patent Application Laid-Open No. 8-33960 contains a large amount of MgO component having a high melting point. There is a problem such as dissolution and decomposition on the surface of the molten steel is not good and accordingly the insulation is not uniformly dispersed on the surface of the molten steel, insufficient insulation and secondary oxidation of the molten steel.

이에 본 발명은 상기와 같은 문제점을 해결하기 위하여 제안된 것으로서, 폐펄프슬러지(waste pulp sludge)를 이용하므로써 기존의 탄화왕겨와 달리 용강중에 가탄됨을 방지함은 물론 기존의 화학적 보온재보다 용강표면온도를 지속적으로 보온할 수 있는 용강표면보온재를 제공하고자 하는데 그 목적이 있다.Therefore, the present invention has been proposed to solve the above problems, by using waste pulp sludge (waste pulp sludge), unlike the conventional charcoal chaff prevents in the molten steel, as well as the surface temperature of molten steel than conventional chemical insulation The purpose is to provide a molten steel surface insulation that can be continuously insulated.

도1은 종래재와 본 발명의 보온재를 적용한 경우 용강 표면에서의 보온효과를 경시적으로 보이는 그래프1 is a graph showing the heat retention effect on the molten steel surface over time when the heat insulating material of the prior art and the present invention are applied;

도2는 종래재와 본 발명의 보온재를 적용한 경우 용강 표면에서의 보온재 두께를 분석한 그래프Figure 2 is a graph analyzing the thickness of the thermal insulation material on the molten steel surface when the conventional material and the thermal insulation material of the present invention is applied

상기 목적달성을 위한 본 발명은 중량%로, 폐펄프슬러지: 70~80%, 코크스: 5~12중량%, CaO: 4~7%, 및 MgO: 2~5%를 포함하여 구성되는 용강표면보온재에 관한 것이다.The present invention for achieving the above object by weight, molten steel surface consisting of waste pulp sludge: 70 to 80%, coke: 5 to 12% by weight, CaO: 4 to 7%, and MgO: 2 to 5% It is about insulation.

이하, 본 발명에 대하여 자세히 설명한다.Hereinafter, the present invention will be described in detail.

우선, 본 발명의 보온재의 주성분인 폐펄프슬러지는 제지공장에서 발생되는 폐기물로서, 그 주성분은 SiO2와 Al2O3이고, 나머지는 Fe2O3와 회분(ash)이다. 상기 폐펄프슬러지는 용강의 표면에서 열발산을 방지하여 보온역할을 한다. 그러나, 폐펄프슬러지의 함량이 70중량%(이하, 단지 `%')이면 용강의 보온성이 지속되지 못하고, 80%를 초과하게 되면 용강중에 균일하게 분산되지 못하여 보온성이 저하되게 되어 바람직하지 못하다. 본 발명에 부합되는 폐펄프슬러지는 SiO2가 32~60%이고 Al2O3가 18~40% 함유된 것이다. 바람직하게는 상기 SiO2와 Al2O3의 중량비가 1.2~2.4인 것을 사용하는 것이다.First, waste pulp sludge, which is a main component of the thermal insulation material of the present invention, is waste generated at a paper mill, and its main components are SiO 2 and Al 2 O 3 , and the remainder is Fe 2 O 3 and ash. The waste pulp sludge prevents heat dissipation on the surface of molten steel and acts as a thermal insulation. However, if the content of the waste pulp sludge is 70% by weight (hereinafter, only '%'), the insulation of molten steel does not continue, and if it exceeds 80%, the insulation may not be uniformly dispersed in the molten steel, which is undesirable. Waste pulp sludge according to the present invention contains 32 to 60% SiO 2 and 18 to 40% Al 2 O 3 . Preferably, the weight ratio of the SiO 2 and Al 2 O 3 is from 1.2 to 2.4.

상기 코크스는 용강 표면에 투입되어 발열반응하여 보온재에 폐펄프슬러지만 존재할 때보다 용강의 보온성을 오래 지속시켜 주는 역할을 한다. 그러나, 상기 코크스의 함량이 5%미만으로 되면 보온성을 계속 유지하는 역할이 미흡한 반면 12%를 초과하면 용강 표면의 보온은 양호하나 오히려 탄소가 용강속으로 가탄될 가능성이 많아 바람직하지 않다.The coke is injected into the molten steel surface to exothermic reaction and plays a role of maintaining the warmth of molten steel longer than when the waste pulp sludge in the insulating material. However, if the content of the coke is less than 5%, the role of maintaining warmth is insufficient, while if the content of the coke exceeds 12%, the warmth of the molten steel surface is good, but the carbon is likely to be burnt into the molten steel, which is not preferable.

상기 생석회(CaO)는 용강의 슬래그 염기도를 조정하는 동시에 결합제로서의 역할을 한다. 상기 생석회는 4%미만으로 첨가되면 저염기도 조정이 안되어 내화연와가 손상될 수 있으며, 7%를 초과하여 용강표면에 분산투입되었을 때 백연이 발생되어 환경공해를 유발하므로 바람직하지 않다.The quicklime (CaO) acts as a binder while adjusting the slag basicity of molten steel. If the quicklime is added in less than 4%, low salt can not be adjusted to damage the refractory edema, and when more than 7% dispersed in the molten steel surface is not preferable because white smoke is generated to cause environmental pollution.

상기 마그네시아(MgO)는 보온재에 첨가되어 열전도율을 상승시킨다. 그러나, 그 함량이 2%미만이면 열전도율 상승 역할이 저하되어 보온성이 열화되며, 5%초과되면 융점이 높고 용강 표면에 보온재가 잘 고르게 퍼지지 않아 보온효과가 떨어져 바람직하지 않다.The magnesia (MgO) is added to the thermal insulation material to increase the thermal conductivity. However, if the content is less than 2%, the role of increasing the thermal conductivity is lowered, and the thermal insulation is deteriorated. If the content is more than 5%, the melting point is high and the thermal insulation does not spread evenly on the molten steel surface.

상기한 조성을 갖는 본 발명의 보온재는 용강 표면에 균일하게 퍼져 용강의 보온효과가 확실하며, 특히 용강중에 탄소가 가탄되지 않고 대기중의 공기와 용강이 2차산화로 인한 용강오염을 방지한다. 즉, 본 발명의 보온재는 폐펄프중에 함유된 SiO2성분과 코크스가 신속하게 반응식1과 같은 반응을 일으켜 직접 탄화규소(SiC)를 생성하기 때문에 탄소가 용강중으로 가탄될 가능성이 적고, 보온재가 용강표면에 균일하게 분산될 수 있다.The thermal insulation material of the present invention having the above composition is uniformly spread on the surface of molten steel to ensure the warming effect of molten steel, and in particular, prevents molten steel pollution due to secondary oxidation of air and molten steel in the air without carbonization. That is, the heat insulating material of the present invention is unlikely to be carbonized in molten steel because the SiO 2 component and the coke in the waste pulp rapidly react as shown in Scheme 1 to directly generate silicon carbide (SiC), and the heat insulating material is molten steel. It can be uniformly dispersed on the surface.

SiO2+ 3C → SiC + 2COSiO 2 + 3C → SiC + 2CO

또한, 반응식1과 같이 발생되는 탄화규소로 인해 보온재가 액상의 용강 표면에서 고상화되기 쉬워 종래의 보온재보다도 보온 효과가 오래 지속되는 장점이 있다.In addition, the thermal insulation material is easily solidified on the liquid molten steel surface due to the silicon carbide generated as in Scheme 1, and thus, the thermal insulation effect lasts longer than the conventional thermal insulation material.

이외에도 본 발명의 보온재는 Al2O3와 같은 개재물 형성을 사전에 방지하여 강의 품질향상에 큰 역할을 하며, 종래의 보온재에 비하여 CaO나 MgO의 함량이 적어 백연발생이 적고, 이에 따라 환경오염을 방지하는데도 일조를 한다.In addition, the thermal insulation material of the present invention prevents the formation of inclusions such as Al 2 O 3 in advance, and plays a large role in improving the quality of the steel, and the content of CaO and MgO is less than that of the conventional thermal insulation material, so that less white smoke is generated. It also helps to prevent it.

한편, 본 발명의 보온재는 펠리타이저(pelletizer)에서 펠릿(pellet)과 같은 과립형으로 제조되어 사용하면 더욱 작업성이 좋다.On the other hand, the thermal insulation material of the present invention is more workability when used in a granular form such as pellet (pellet) in a pelletizer (pelletizer).

이하, 본 발명을 실시예를 통하여 구체적으로 설명한다.Hereinafter, the present invention will be described in detail through examples.

실시예1Example 1

표1과 같은 조성을 갖도록 원료를 배합한 다음, 여기에 바인더로서 점분을 약 5~8%첨가하여 펠릿타이저에서 펠릿형태의 보온재를 제조하였다. 제조된 각 보온재는 약 100kg의 유도용해로에서 표면온도가 약 1550℃인 용강의 표면에 약 3kg를 뿌린 다음, 일정 시간 동안 열특성장치를 통해 용강의 표면온도변화를 측정하고, 그 대표적인 결과를 도1에 나타내었다.After mixing the raw materials to have a composition as shown in Table 1, by adding about 5 to 8% of the powder to the binder as a binder to prepare a pellet-type heat insulating material in a pelletizer. Each prepared insulation is sprayed about 3kg on the surface of molten steel with surface temperature of about 1550 ℃ in an induction melting furnace of about 100kg, and then measured the surface temperature change of molten steel through thermal characteristics device for a certain time, and the representative result is shown. 1 is shown.

도1에서도 알 수 있듯이, 본 발명의 보온재를 용강의 표면에 도포되었을 때 용강의 온도를 오랫동안 일정하게 유지함을 알 수 있었다.As can be seen from Figure 1, it was found that the temperature of the molten steel is kept constant for a long time when the heat insulating material of the present invention is applied to the surface of the molten steel.

반면, 왕겨를 사용한 종래재의 경우 보온재를 투입하지 않은 나탕상태의 용강온도보다는 높지만, 보온재 도포초기부터 용강의 표면온도가 급격히 저하되어 초기 용강의 표면온도를 유지하지 못함을 알 수 있었다.On the other hand, in the case of the conventional material using chaff is higher than the molten steel temperature of the molten state in which the insulation is not added, it can be seen that the surface temperature of the molten steel is rapidly lowered from the initial application of the insulation to maintain the surface temperature of the initial molten steel.

또한, CaO성분이 다소 많이 첨가된 비교재1의 보온재는 백연발생이 심하였으며, MgO성분이 본 발명의 조건범위를 벗어난 비교재2의 보온재는 용강 표면에서 고르게 퍼지질 않았으며, 폐펄프슬러지가 본 발명의 조건범위를 벗어난 비교재3의 보온재는 용강의 표면온도 보온 효과가 종래재와 비슷하였다.In addition, the thermal insulation material of Comparative Material 1, in which CaO component was added a little more, was prone to white smoke, and the thermal insulation material of Comparative Material 2, in which MgO component was out of the condition range of the present invention, did not spread evenly on the molten steel surface. The thermal insulation material of Comparative Material 3 outside the condition range of the present invention was similar to the conventional material in the surface temperature insulation effect of molten steel.

한편, 폐펄프슬러지를 이용한 본 발명의 보온재에 대한 용강과의 반응을 살펴본 결과, 폐펄프슬러지중의 SiO2함량이 32~60%, 더욱 바람직하게는 32~42%의 범위인 경우 가장 반응속도가 빨랐다. 따라서, 폐펄프슬러지를 이용하여 보온재를 제조할 때는 최종 보온재의 SiO2함량을 약 32~60%의 범위를 갖도록 폐펄프슬러지를 배합이 바람직하다.On the other hand, as a result of examining the reaction with the molten steel for the heat insulating material of the present invention using waste pulp sludge, the most reaction rate when the SiO 2 content in the waste pulp sludge ranges from 32 to 60%, more preferably from 32 to 42% Was fast. Therefore, when preparing the heat insulating material using the waste pulp sludge, it is preferable to mix the waste pulp sludge so that the SiO 2 content of the final heat insulating material has a range of about 32 to 60%.

실시예2Example 2

실시예1과 같이, 발명재1과 발명재2 및 종래재의 보온재를 용강에 도포한 다음, 약 10분 경과되었을 때 용강의 표면위에 도포된 보온재의 두께를 측정하고, 그 결과를 도2에 나타내었다.As in Example 1, Insulation Material 1, Insulation Material 2, and Insulation Material of Conventional Material were applied to molten steel, and after about 10 minutes, the thickness of the Insulation Material applied on the surface of molten steel was measured, and the result is shown in FIG. It was.

도2에 나타난 바와 같이, 본 발명의 보온재는 종래의 보온재에 비하여 상부에는 분말층이 두텁게 형성되어 보온효과가 큼을 알 수 있었다.As shown in Figure 2, the heat insulating material of the present invention compared to the conventional heat insulating material was formed in the upper thicker powder layer was found to have a large thermal effect.

상기한 바와같이, 본 발명의 보온재는 레들 또는 턴디쉬에 투입되었을 때 용강의 표면에 고르게 분산되면서 백연발생이 거의 없고 또한 강의 표면온도 보온이 오랫동안 지속되는 효과가 있다.As described above, the thermal insulation material of the present invention is evenly dispersed on the surface of the molten steel when it is added to the ladle or tundish, there is almost no white smoke and also has the effect of maintaining the surface temperature of the steel for a long time.

Claims (3)

중량%로, 폐펄프슬러지: 70~80%, 코크스: 7~12%, CaO: 4~7%, 및 MgO: 2~5%를 포함하여 구성되는 용강표면보온재Molten steel surface insulation comprising weight percent, waste pulp sludge: 70-80%, coke: 7-12%, CaO: 4-7%, and MgO: 2-5% 제1항에 있어서, 상기 폐펄프슬러지는 SiO2: 32~60중량%, Al2O3: 18~40중량%, 및 잔부는 Fe2O3와 회분이고, 상기 SiO2와 Al2O3의 비가 1.2~2.4의 범위임을 특징으로 하는 용강표면보온재The method of claim 1, wherein the waste pulp sludge is SiO 2 : 32 to 60% by weight, Al 2 O 3 : 18 to 40% by weight, and the balance is ash and Fe 2 O 3 ash, the SiO 2 and Al 2 O 3 Molten steel surface insulation, characterized in that the ratio of 1.2 to 2.4 제1항에 있어서, 상기 보온재는 펠릿형태임을 특징으로 하는 용강표면보온재2. The molten steel surface insulating material according to claim 1, wherein the heat insulating material is in a pellet form.
KR1019980034964A 1998-08-27 1998-08-27 A heat insulator for molten steel KR100265212B1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20040040844A (en) * 2002-11-08 2004-05-13 주식회사 포스코 Method for charging slag forming reduction type heat insulation material in receive ladle
CN105051251A (en) * 2013-02-20 2015-11-11 应用材料公司 Apparatus and methods for carousel atomic layer deposition
US10197385B2 (en) 2015-01-22 2019-02-05 Applied Materials, Inc. Intelligent hardstop for gap detection and control mechanism

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20100081381A (en) * 2009-01-06 2010-07-15 (주)랜드브릿지 Heat insulator for molten steel

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20040040844A (en) * 2002-11-08 2004-05-13 주식회사 포스코 Method for charging slag forming reduction type heat insulation material in receive ladle
CN105051251A (en) * 2013-02-20 2015-11-11 应用材料公司 Apparatus and methods for carousel atomic layer deposition
US10197385B2 (en) 2015-01-22 2019-02-05 Applied Materials, Inc. Intelligent hardstop for gap detection and control mechanism

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