• The Journal of the Petrological Society of Korea
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• v.12 no.3
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• pp.135-153
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• 2003

In order to understand its origin and petrogenesis, petrochemical studies of major, trace elements, REE, and stable isotopes of oxygen and carbon from the Hongcheon Fe-REE deposits have been investigated. The Hongcheon Fe-REE deposit intruding into Precambrian metasedimentary rocks consists of magnetite, various carbonates such as ankerite, siderite, magnesite and strontianite, monazite, aegirine-augite, Na-amphibole, and sulfides. Compared with major elements abundances of typical ferro-carbonatites, the Hongcheon Fe-REE deposit is enriched in FeO and depleted in CaO with increasing of $SiO_2$, where $TiO_2$and $A1_2O_3$increased and CaO, FeO, MgO and $P_2O_5$ are slightly decreased, but those are rather scattered and their trends are somewhat ambiguous. V Ni, U and Rb slightly increasing with of $SiO_2$increase and scattering or no trends of other detected elements. Nb, Zr and Zn are depleted then the abundances of typical ferro-carbonatites (Woolley and Kempe, 1989). In rare earth elements a large enrichment of total REE (maximum 14.8 wt%) and LREE relative to chondrites and HREE depleted more then the values of ferro-carbontites therefore La/Lu ratios shows large abundances (max. 16,197). The results of stable isotopes of O and C from minerals of ankerite and strontianite and whole rocks represent studied rocks are from igneous carbonatitic melts. Although petrochemical characteristics of the Hongcheon Fe-REE deposits are somewhat different from normal ferro-carbonatites from the world, this discrepancy suggests another conclusion that petrochemical characteristic of the studied Fe-REE mineralized rocks are similar to those of phoscorites from Kovdor, Russia and Sokli, Finland showing the same petrochemical compositions described above.

• Journal of Korea Foundry Society
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• v.28 no.6
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• pp.243-251
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• 2008

자동차 및 항공기 부품용 고온 다이캐스팅 마그네슘 합금에 대한 연구가 활발히 진행되고 있다. 알루미늄을 주된 합금원소로 하여 희토류원소나 알칼리토금속 등을 첨가하는 3원계 합금 및 각 원소들을 조합하는 4원계 합금이 개발되었다. 이들 합금의 크립 저항성은 금속간 상에 의한 결정 입계 강화에 기인한다. 그 동안의 합금조성 개발의 핵심은 결정 입계의 이동을 유발하여 고온 변형을 유발하는 고온 불안정 석출상의 생성을 억제하는 것이었다. Mg-Al계 합금에 희토류원소를 첨가하면 고온 안정상의 생성으로 고온 특성이 향상되지만 희토류원소의 경제성이 단점이다. 고비용의 희토류원소를 대신하기 위해 알칼리토금속을 첨가하는 합금 및 이들 원소를 조합하는 합금이 개발되었다. 본고에서는 알칼리토금속을 첨가할 경우에 발생하는 생산성의 저하 등의 단점을 보완하는 알칼리토금속산화물이 첨가된 합금을 소개하였는데 이는 1) 비고용성 2) 융점유지 3) 주조성유지 4) 재활용성 5) 경제성 등의 특징이 있다.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.47-50
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• 1997

희토류원소의 광 환원 침전 특성이 연구되었다. 환원제로 isopropyl alcohol, 침전제로 (NH$_4$)$_2$SO$_4$가 사용되었다. 그리고 250nm의 파장을 방출하는 수은 램프가 사용되었다. Eu원소만을 함유하는 용액으로부터 Eu+3의 Eu+2로의 광 환원 결과는 97%이상이었으며 과산화수소가 소량 첨가되었을 경우 침전 속도는 증가하였다. 이 결과를 토대로 하여 희토류원소들(Sm,Eu,Gd)을 함유하는 수용액과 유기용액(HDEPH-Dodecan)에 UV광을 조사하였을 시 선택적으로 Eu을 분리해 낼 수 있었다. Eu의 침전 회수율은 두 상의 경우 모두 97%이상이었다.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.63-68
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• 1986

Elution behavior of rare earth elements have been investigated with the EDTA solution as an eluent using cation exchange resin. Definite amount of the complexed rare earth ions at pH 8.4 is adsorbed through the cation exchanger containing cupric ion as a retaining ion and eluted with EDTA solution. The rare earth ions are eluted more rapidly in the above method than in the method in which uncomplexed rare earth ions are adsorbed on the cation exchange resin bed. In this method, the elution time and amount of eluent are saved but the resolution values also decreased a little. The elution order of complexed ion was determined in accordance with the stability constant of complexes with rare earth elements.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.280-283
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• 2003

희토류원소는 변성작용, 변질작용 및 풍화작용의 영향 측면에서 다른 원소에 비해 영향을 덜 받는 특성 (Taylor and McLennan, 1985; McLennan, 1989; Lee et at., 1994)과 더불어 암석생성과정을 이해하는 데 매우 중요한 기초자료로 이용되고 있으며 지구의 생성과정을 이해하는데 중요하게 인식되고 있다. 최근의 연구결과에 의하면 퇴적물의 기원을 밝히는데 있어서 희토류원소가 매우 유용한 도구가 될 수 있음이 밝혀졌으며(Piper, 1985; Cullers et al., 1987; Elderfield et at., 1990), 지표수 혹은 지하수에서의 희토류원소 존재도가 지하수의 유동방향을 지시해준다는 연구결과가 보고되기도 하였다(Johannesson et al., 1996, 1997). (중략)

• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.692-696
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• 1992

$NH_4^+ form cation exchange resin was used to separate one rare earth element from the rare earth mixture solution using Ln-EDTA eluent. Rare earth mixture solution was passed through the resin bed and eluted with 0.1M La-EDTA solution as an eluent. In here all the rare earth element except lanthanum ion are eluted and lanthanum ion absorbed in resin bed is eluted using 0.1M EDTA solution. If Ce-EDTA solution instead of La-EDTA solution was used as an eluent, all the rare earth element except cerium ion are eluted and cerium ion is eluted with 0.1M EDTA solution. This method can be applied to separate the individual rare earth element from the mixture. The separation mechanism is as follows: Absorption : 3RNH_4 ＋ Ln^{3+} = R_3Ln ＋ 3NH_4^+, La-EDTA elution : R_3Ln ＋ La-Y- = R_3La ＋ Ln-Y-, EDTA elution : R_3La ＋ HY^3- = La_-Y ＋ RH ＋ 2R^-.$

• Journal of the Mineralogical Society of Korea
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• v.26 no.4
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• pp.245-262
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• 2013

We analyzed 29 surface sediment samples in five submarine volcanoes (TA12, TA19, TA22, TA25, and TA26) located in the southern part of the Tonga arc for trace elements and rare earth elements to investigate characteristics of the hydrothermal alteration of surface sediments. Based on analytical results of trace element and rare earth element (REE), surface sediments of TA12, TA19, and TA22 submarine volcanoes, which are located in the northern part of the study area, were very little or not influenced by hydrothermal fluids. In contrast, some stations of TA25 and TA26 submarine volcanoes were strongly affected by hydrothermal fluids. However, these two submarine volcanoes showed different features in element concentration in the sediments. Some stations of TA25 submarine volcano showed enrichment of Ni, Cu, Sn, Zn, Pb, Cr, Cd, Sb, W, Ba, Ta, Rb, Sr, and As, however, those of TA26 submarine volcano showed enrichment of Sn, Zn, Pb, Cd, Sb, Ba, Rb, and Sr. Stations which enriched trace elements were observed, enriched REEs were also observed. Average upper continental crust (UCC)-normalized REE patterns of the surface sediments generally showed low light REE (LREE) abundances and increased heavy REE (HREE) abundances. Eu enrichment was identified at several stations of TA25 and TA26 submarine volcanoes. In addition, enrichment of Ce was found at some stations of TA26 submarine volcano and these enrichment patterns were similar with hydrothermal fluid of near stations. Furthermore, TA25 and TA26 submarine volcanoes showed different enrichment characteristics of trace elements and REE. Trace elements were concentrated at TA25 submarine volcano. TA26 submarine volcano, on the other hand, observed highly enrichment of REE especially, Eu and Ce. As a result of the investigation, the characteristics and concentrations of REEs and trace elements in the surface sediments of each submarine volcano can be applied to identify hydrothermal alteration of sediments during exploration for hydrothermal deposits.

• Journal of the Korean Chemical Society
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• v.29 no.2
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• pp.183-190
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• 1985

The elution behaviors of the rare earths was carried out in the iminodiacetic acid solution of various pH as eluent using ion exchange resin. The optimum eluent for the quantitative separation of $Eu^{3+},\;Pr^{3+},\;Ce^{3+}\;and\;La^{3+}$ were 0.0301M IMDA solution of pH 8.00 and 9.00 at 5cm column of the resin Dowex 50${\times}$8 (100-200 mesh). The elution order of the rare earth elements was in order of the atomic number of those elements. From the elution behavior of rare earth and u.v spectrum we found that the complexed rare earth species with IMDA changed according to pH of IMDA.

• The Journal of the Petrological Society of Korea
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• v.13 no.4
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• pp.238-243
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• 2004

Duwon meteorite was fallen on 23 November 1943 in Duwonmyeon, Goheung, Jeolanam-Do. We measured rare earth element abundance of Duwon meteorite by isotope dilution thermal ion mass spectrometry (ID-TIMS) and ICP-MS. As a result, except La and Ce, abundance of other rare earth element show a correspondence within 10％ of error range. However, La and Ce show more than 70％ in abundance, which is considered due to 1) experimental procedure or 2) inhomogeneity of sample. Leedey meteorite was fallen on 25 November 1943 in Dewey County, Oklahoma, USA. which suggested that fallen difference between Leedey and Duwon meteorites is only 2 days. Leedey and Duwon meteorites are classified as ordinary chondrite of L6 type. In Leedey chondrite-normalized REE pattern, Duwon meteorite shows nearly flattened, which suggests close relationship between Leedey and Duwon meteorites meteoritically or cosmochemically.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.112-115
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• 2003

희토류원소는 원자번호 57의 La으로부터 원자번호 71의 Lu까지의 원소군으로서, 지난 40여년간 지구화학 및 우주화학의 연구분야에서 상당한 관심을 받아왔다 (Masuda et al., 1973; Taylor and McLennan, 1985: Johannesson et at., 1997). 최근에는 지하수, 호소와 같은 육상수에서의 희토류원소의 농도가 그들의 지구화학적 진화에 영향을 주는 과정의 잠재적인 지시자로서 주목을 받고 있다 (Sholkovitz, 1992; Johannson et at., 1997). (중략)