• Journal of the Korean Ceramic Society
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• v.12 no.4
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• pp.37-42
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• 1975

철(II)이온을 안정화 하기위하여, 2산화 규소와, 구상, 입방체상 및 침상의 서로 다른형태의 산화 제2철로부터 규산철을 합성하였다. 메타놀증기로 포화시킨 질소까스를 튜브로에 도입시켜 얻은 환원성 분위기속에서, 114$0^{\circ}C$에서 11$65^{\circ}C$의 온도범위에서, 가스유속을 0.13 및 0.25l/min. 로서, 환원시간 4-150분동안 교상반응을 진행하였다. 반응생성의 동태를 오르자트 가스분석으로 검토하였으며, 생성물의 확인은 X-선 회절시험 및 감량정량에 의하였으며, 결과는 다음과 같다. 1 : 1.1의 몰비로 혼합한 산화제2철과 2산화 규소의 경우, 가스유속이 0.13l/min일 때, 규산철 합성반응시간은 구상, 입방체상 및 침상산화철에 있어서 각기 8-27분, 10-16분 및 6-7분으로 구상의 경우가 범위가 가장 넓었다. 또한, 반응속도는 산화제2철의 표면적의 평방근에 비례하였고 반응시간의 평방근에 역비례하였다.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.394-403
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• 2016

$H_2$ production by chemical looping is an efficient method to convert hydrocarbon fuel into hydrogen with the simultaneous capture of concentrated $CO_2$. This process involves the use of an iron based oxygen carrier that transfers pure oxygen from oxidizing gases to fuels by alternating reduction and oxidation (redox) reactions. The enhanced reactivities of copper oxide doped iron-based oxygen carrier were reported, however, the fundamental understandings on the interaction between $Fe_2O_3$ and CuO are still lacking. In this study, we studied the effect of dopant of CuO to $Fe_2O_3/ZrO_2$ particle on the morphological changes and the associated reactivity using various methods such as SEM/EDX, XRD, BET, TPR, XPS, and TGA. It was found that copper oxide acted as a chemical promoter that change chemical environment in the iron based oxygen carrier as well as a structural promoter which inhibit the agglomeration. The enhanced reduction reactivity was mainly ascribed to the increase in concentration of $Fe^{2+}$ on the surface, resulting in formation of charge imbalance and oxygen vacancies. The CuO doped $Fe_2O_3/ZrO_2$ particle also showed the improved reactivity in the steam oxidation compared to $Fe_2O_3/ZrO_2$ particle probably due to acting as a structural promoter inhibiting the agglomeration of iron species.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.107-111
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• 2006

The samples collected from two reactors are analyzed by X-ray diffraction and M$\ddot{o}$ssbauer spectroscopy in this study. It is concluded that the iron oxide crystal attached on anthracite media which possesses catalytic ability is identified to be Ferrihydrite, regardless of the value of pH from the analysis of the iron oxide. Iron oxide in Batch reactor is identified to be Microcrystalline goethite.

• Economic and Environmental Geology
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• v.44 no.3
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• pp.203-215
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• 2011

Geochemical and mineralogical properties of a contamited soil should be taken into account to decide a remediation strategy for a given contaminant because development and optimization of soil remedial technologies are based on geochemical and mineralogical separation techniques. The objective of this study was to investigate the geochemical and mineralogical characteristics of arsenic-contaminated soils. The arsenic-contaminated soil samples were obtained from Chonam gold mine, Gwangyang, Chonnam, Particle size analysis, sequential extraction, and mineralogical analyses were used to characterize geochemical and mineralogical characteristics of the As-contaminated soils. Particle size analyses of the As-contaminated soils showed the soils contained 17-36% sand, 25-54% silt, 9-28% clay and the soil texture were sandy loam, loam, and silt loam. The soil pH ranged from 4.5 to 6.6. The amount of arsenic concentrations from the sequential soil leaching is mainly associated with iron oxides (1 to 75%) and residuals (12 to 91%). Major minerals of sand and silt fractions in the soils were feldspar, kaolinite, mica, and quartz and minor mineral of which is an iron oxide. Major minerals of clay fraction were composed of illite, kaolinite, quartz, and vermiculite. And minor minerals are iron oxide and rutile. The geochemical and mineralogical analyses indicated the arsenic is adsorbed or coprecipitated with iron oxides or phyllosilicate minerals. The results may provide understanding of geochemical and mineralogical characteristics for the site remediation of arsenic-contaminated soils.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.105-109
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• 2000

종래의 핵연료소결체가 혼합산화물 혹은 이산화우라늄중 한가지 핵연료만으로 구성한 것과 달리 내부를 저농축 이산화우라늄 핵연료로 채우고 그 외부를 링형태의 혼합산화물 핵연료로 둘러 싼 이중구조를 특징으로 한다. 이러한 형태의 핵연료소결체는 중심영역의 핵분열반응률 줄임으로써 핵분열 기체생성, 핵연료봉 중심온도와 평균온도를 낮추어 준다. 이는 핵분열 기체방출을 낮추어 혼합산화물 핵연료봉 성능을 향상시키고 방출 연소도를 증가시키는 효과가 있다.

• Journal of the Korean Magnetics Society
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• v.15 no.1
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• pp.37-41
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• 2005

We prepared water-based magnetic fluids with the spent iron oxide catalysts which were used in the styrene monomer production process. The catalyst was composed with 70% magnetite and alkali metals. The water-based magnetic fluids were prepared by mechanical grinding with olecic acid as a surfactant and water in an attritor. The magnetization of the water-based magnetic fluids was 22 emu/g in the 10 kOe.

• Journal of the Mineralogical Society of Korea
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• v.29 no.2
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• pp.73-78
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• 2016

The oxidation states of structural Fe in clay minerals often reflect the paleo-redox conditions of the depositional environments. It is inevitable to utilize the high resolution of transmission electron microscopy (TEM) to investigate the mechanism of mineral transformation at nano-scale. The applications of TEM- electron energy loss spectroscopy (EELS) for quantification of $Fe(III)/{\Sigma}Fe$ from the K-nontronite formation associated with structural Fe(III) reduction in nontronite under deep subseafloor environment were demonstrated. In particular, quantification of the changes in Fe-oxidation state at nanoscale is essential to understand the mechanisms of minerals formation. The procedure of EELS acquisition, quantitative determination of Fe-oxidation states, and advantages of EELS techniques were discussed.

• The Korean Journal of Quaternary Research
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• v.13 no.1
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• pp.99-106
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• 1999

The surfacial bottom sediments on the nearshore to infer continental shelf off the Taean Peninsular, west coast of Korea are dominantly medium-grained clastic sands. About 60% and 20% of these clastic sands are partly iron-stained quartz and completely iron-stained quartz, respectively. Characteristically glauconite grains are abundantly found in these clastic sands. The mineral compositions of clastic sandy sediments in the study area are very similar to those of East China continental shelf sediments. Accordingly, such iron-stained quartz grains, glauconite grains and associated textural characteristics seem to indicate that those sandy sediments are relict sediments related to past condition, i.e. Quaternary low stands of sea level.

• 전기의세계
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• v.58 no.10
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• pp.20-27
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• 2009

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.390-393
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• 2010

The thermal decomposition rate of ammonium perchlorate with 3% of yellow iron oxide, FeOOH was found to be much faster than with red iron oxide, $Fe_2O_3$. By applying yellow and red iron oxide as a burning rate modifier to HTPB/AP propellant, burning rate of the HTPB/AP propellant with yellow iron oxide was shown to be 10 ~ 25% faster than with red iron oxide. There was no special difference in viscosity and hardness buildup of yellow and red oxide added HTPB/AP formulations.