• Journal of the Korean Ceramic Society
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• v.23 no.2
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• pp.55-63
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• 1986

In variuos physcial and chemical cause of damage of refractories for steel makin the clarification of the wear mechanism of brick is situated on important factor. In the present paper the wear mechanism of high alumina brick for the arc-furnace roof were inves-tigated by means of XRD, EPMA. SEM and microscopy. The results obtained were summerized as follows : (1) The altered layers which exist in high alumina brick used for arc-furnace roof were verified by mineral chemical analysis and EPMA. (2) The diffusion of materials combined with slag dust and iron oxide from furnace atmosphere in high basic process from hot face to interior was verified. (3)Activation energy for the synthesized slag permeated into the unused brick texture was 47-51 kcal per mole.

• Journal of the Korean Ceramic Society
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• v.11 no.1
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• pp.23-28
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• 1974

1. Stage crushing by jaw crusher, steel mortar, and ball mill in turn has shown an inclination to increase the distribution of andalusite in coarse particles as well as to increase that of micas in fine particles. 2. Water elutriation was effective for the removal of muscovite and magnetic separation was effective for that of Mg-Fe micas such as biotte and chlorite. The process of concentration and that of purification are diagramatized respectively as follows: Concentration; Raw andalusite${\lightarrow}$Crushing${\lightarrow}$Screening${\lightarrow}$Water elutriation${\lightarrow}$Magnetic separation Purification; Concentrated andalusite${\lightarrow}$Calcination${\lightarrow}$Ball milling${\lightarrow}$Screening${\lightarrow}$Water elutriation${\lightarrow}$Magnetic separation${\lightarrow}$Acid washing.

• Journal of the Korean Ceramic Society
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• v.17 no.3
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• pp.145-150
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• 1980

This paper deals with the clay-bonded silicon carbide refractory saggars in terms of its oxidation resistance. Oxidation is one of the major causes of failure in silicon carbide refractory saggars during its services. Various anti-oxidation additives are coated on or added into silicon carbide refractories and their effects are studied while other conditions are equal. Several conclusions can be derived for optimum anti-oxidation additive as: 1. The additive should wet each silicon carbide grain completely during its firing. 2. The additive should have high viscosity at temperatures around $1, 350^{\circ}C$ where most silicon carbide refractory saggars are being used. 3. The additive should have ability to absorb or desorb oxygen depending on the local atmosphere inside of saggar during it service. 4. The addition should be kept as minimum as possible to prevent any "sweating" or "bloating" phenomena.ing" phenomena.mena.

• Journal of the Korean Ceramic Society
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• v.11 no.4
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• pp.5-18
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• 1974

본 연구에 있어서는 연료유의 연소에 의한 내화물의 부식을 연구하기 위하여 시멘트소성용 회전가마, 보일러 및 판유리제조용 탱크가마에 쓰이는 여러 내화물을 짤라서 그 가운데에 구멍을 파고 중유재의 주성분인 V2O5, Na2CO3, Fe2O3, Fe 및 황산철을 미리 그 구멍속에 넣어 응용 확산시킨 다음 이들을 그들의 상용온도인 145$0^{\circ}C$로 황 함유량이 다른 연류유로 소성하여 얻은 결과는 다음과 같다. 일반적으로 5산화 바나듐-알루미나, 고알루미나질 및 염기성 내화물; 산화나트륨-고알루미나질, 실리마나이트질 및 염기성 내화물은 2%미만의 황 함유 연류유소성에 의하여 부식이 적고 3.5%이상의 황하유 연료유소성시는 황에 의하여 대개가 침식을 당하였다. 무수 아황산 분위기속에서 규산알루미늄 및 구석계의 내화점토질내화물은 산화철이 환원되어 색이 연해지고 고알루미나질 벽돌은 색이 짙어지는 경향이 있고 산화철은 황산철로 변하여 풍화의 원인이 되어 침식을 당하게 되었고, 소성시간이 길면 길수록 부식은 증가하고 황산소다보다 탄산소다에 의하여 훨씬 더 많이 부식을 당하였다.

• Journal of the Korean Ceramic Society
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• v.12 no.3
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• pp.3-7
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• 1975

The usefulness of the domestic shale contained chiastolite as additive were investigated. Crude mixed minerals were separated into shale and chiastolite. Refractory body added simple component or multiple components as additives was obtained when firing at 125$0^{\circ}C$ for each body. Compressive strength, refractories, apparent sp. gr., water absorption, corrosion test by slag, hot linear expansion were measured and X-ray diffraction analysis was observed. As the result of study, refractory body contained separated minerals as additives showed slightly increasing in refractoriness, lowering in sintering effect, the excellent effect for corrosion resistance by acidic slag. With more containing separated minerals, hot linear expansion for the body can be decreased.

• Ceramist
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• v.9 no.6
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• pp.12-17
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• 2006

One of characteristic of $Cr_2O_3-containing$ refractory is excellent resistance to corrosion. However, there is a problem that hexa-valent chromium, which is noxious to the human body, is easily formed by reaction between the refractory and slag with CaO, $Na_2O$ and/or $K_2O$. In this article, the reason why the $Cr_2O_3-containing$ refractory has excellent corrosion resistance qualities, he conditions under which hexa-valent chromium formed, methods for suppressing generation of hexa-valent chromium and the possibility of the refractory components excluding $Cr_2O_3$ for the furnace are described as a base of development of further excellent refractories.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.2
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• pp.169-178
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• 2016

The properties of wastes for melting need to be considered to minimize the maintenance of refractory and to discharge the molten slags smoothly from a plasma torch melter. When the nonflammable wastes from nuclear facilities such as concrete debris, glass, sand, etc., are melted, they become acid slags with low basicity since the chemical composition has much more acid oxides than basic oxides. A molten slag does not have good characteristics of discharge and is mainly responsible for the refractory erosion due to its low liquidity. In case of a stationary plasma torch melter with a slant tapping port on the wall, a fixed amount of molten slags remains inside of tapping hole as well as the melter inside after tapping out. Nonmetallic slags keep the temperature higher than melting point of metal because metallic slags located on the bottom of melter by specific gravity difference are simultaneously melted when dual mode plasma torch operates in transferred mode. In order to minimize the refractory erosion, the compatible refractories are selected considering the temperature inside the melter and the melting behavior of slags whether to contact or noncontact with molten slags. An acidic refractory shall not be installed in adjacent to a basic refractory for the resistibility against corrosion.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.1
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• pp.63-69
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• 2015

This work aimed to analyze current status of by-products generation and industrial symbiosis network in Pohang steel industrial complex, South Korea. Pohang is the largest generating city of both total and the non-recycled industrial waste in Gyeongsangbuk-do, and most of the waste is generated from Pohang steel industrial park. Symbiosis map in Pohang steel industrial park shows that most of the current material symbiosis in the industrial park is for waste refractories and slag.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.626-631
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• 1997

AlSiCa powders were prepared from the domestic Hadong Kaolin ($Al_2O_3{\cdot}2SiO_2{\cdot}2H_2O$). As a result of the reaction of Hadong Kaolin and carbon powder at reducing atmosphere, $Al_2O_3{\cdot}SiC$ composite started to form at $1300^{\circ}C$ and completed at $1400^{\circ}C$. The optimum amount of carbon was 1:4 in mole ratio. It was found that only bright-green $\beta-SiC$ phase forms when the mixture was packed without carbon powder in alumina crucible.

• The Korean Journal of Ceramics
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• v.6 no.1
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• pp.78-82
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• 2000

Although alumina aggregates have been used as refractory aggregates due to the improved mechanical properties of refractories as a result of the low contraction of alumina aggregates, the aggregates have a difficulty in fabrication due to its low sinterability. Two types of alumina aggregates and a fused alumina aggregate containing transient liquid forming additives are prepared to investigate the sintering characteristics of aggregates. $Al_2O_3$rich composition in the $Al_2O_3$-MgO-$SiO_2$(-$TiO_2$) system is chosen for the transient liquid phase sintering and the final recrystallized bonding phase between grains inside the fused alumina aggregates is found to be a needle-like mullite phase. The flexural strength of alumina bars, reaction-bonded using the paste having a composition of $Al_2O_3$-MgO-$SiO_2$-$TiO_2$, is about 78 MPa, which is one half value of that of pure alumina.