• Title/Summary/Keyword: 희토류 원소

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Study on the Ion Exchange Mechanism of Rare Earth Elements in Several Elution Types (I) (희토류원소의 여러가지 용리형태의 이온교환 메카니즘에 관한 연구 (제 1 보))

  • Ki-Won Cha;Sung-Wook Hong
    • Journal of the Korean Chemical Society
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    • v.33 no.2
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    • pp.232-237
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    • 1989

  • The elution mechanism of rare earth elements in cation exchange resin which was substituted with $NH_4^+,\;Zn^{2+}\;or\;Al^{3+}$ as a retaining ion had been investigated. Rare earths or rare earths-EDTA complex solution was loaded on the top of resin bed and eluted with 0.0269M EDTA solution. When the rare earth-EDTA complex was adsorbed on the $Zn^{2+}\;or\;Al^{3+}$ resin form, retaining ion was complexed with EDTA and liberated rare earths was adsorbed in the resin again. Adsorbed rare earths in resin phase could be eluted by the complexation reaction with EDTA eluent. On $NH_4^+$ resin form, the rare earth-EDTA complex which had negative charge could not adsorbed on the cation exchange resin because the complexation reaction between $NH_4^+$ and EDTA was impossible. So the elution time was much shorter than in $Zn^{2+}\;or\;Al^{3+}$ resin form. When the rare earths solution was loaded on the $Zn^{2+},\;Al^{3+}$ resin form bed, rare earths was adsorbed in the resin and the retaining ion was liberated. Adsorbed rare earths in resin bed was exchanged by EDTA eluent forming rare earths-EDTA complex, and eluted through these processes. On $NH_4^+$ resin form, rare earths loaded was adsorbed by exchange reaction with $NH_4^+$. As the EDTA eluent was added, rare earths was liberated from resin forming negatively charged rare earth-EDTA complex and eluted without any exchange reaction. So the elution time was greatly shortened and there was no metallic ion except rare earths in effluent. When the $Zn^{2+}\;and\;Al^{3+}$ was used as retaining ion, the pH of efflent was decreased seriousely because the $H^+$ liberated from EDTA molecule.

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Differentiation Trend of Rare Earth Elements of the Skaergaard Intrusion (Skaergaard 암체의 희토류의 분화경향)

  • Yun D. Jang
    • Economic and Environmental Geology
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    • v.34 no.6
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    • pp.617-625
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    • 2001

  • The Skaergaard intrusion is widely considered a type example of a strongly fractionated, layered intrusion that has undergone extensive in situ igneous differentiation. The Intrusion, therefore, should be a good locality for modeling trace element vriation in a closed system. Previous studios (Haskin and Haskin, 1968; Faster et al., 1974), however, have suggested thats the rare earth elements in whole rocks and mineeral separates from the Intrusion did not fellow the expected trend for closed system crystatllization. Trace element modeling using published distribution coefficients, modal abundances of the coexisting minerals, and the concentration of trace elements In whole rocks and mineral separates from the Skaergaard Intrusion, reveals that the rare earth elements were significantly Influenced by the crystallization of abundant apatite in the Layered Series suring the final stages of crystallization. The results of trace element modeling also suggcsts that apatite, which appears sporadically in the UBS, is not a primary liquidus phase in these samples as previously suggested (Naslund, 1984) but an interstitial phase that (lid not directly effect trace element abundances In the evolving magma As the Skaergaard magma coaled convection, or convected as small Isolated cells during the final stages of differentiation, an elebated $P_{H2O}$ Induced by accumulation of volatile elements near the roof of the magma chamber ingibited or delayed the precipitation of primary apatite in the UBS If the Skaergaard differentiation Is modeler assuming primary apatite crystallization In the upper par of the LS where abundant modal apatite is present, and only late stage crystallization of apatite In the UBS where apatite Is less abundant, rare earth elements abundances follow a closed system variation trend. These results rule but any differentiation model for the Skaergaard Intrusion that Includesvolumetrically significant injections or discharges of magma Into or out of the chamber during the final 20% of the crystallization history.

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Major, Trace and Rare Earth Element Geochemistry, and Oxygen-Isotope Systematics of Illite/smectite in the Reindeer D-27 Well, Beaufort-Mackenzie Basin, Arctic Canada (카나다 보포트-맥켄지 분지의 일라이트/스멕타이트의 원소 지화학 및 산소동위원소 연구)

  • Ko, J.;Hesse, R.;Longstaffe, F.J.
    • Economic and Environmental Geology
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    • v.28 no.4
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    • pp.351-367
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    • 1995

  • The elemental geochemistry and oxygen isotopes of illite/smectite (I/S) have been studied in relationship to the mineralogical trend in the Reindeer D-27 well, Beaufort-Mackenzie Basin. The increase in concentrations of $K_2O$, Rb and rare earth elements (REE), the decrease in concentrations of tetrahedral elements such as Mg, Ti, Sc, Zn and Zr, and the increase in concentrations of tetrahedral elements such as Be and V can be related to I/S compositions that vary systematically with depth. Layer formulae of S- and I-layers are estimated as $[Al_{1.57}Fe_{.19}Mg_{.31}Ti_{.07}][Si_{3.84}Al_{.16}]O_{10}(OH)_2$ and $[Al_{1.84}Mg_{.16}][Si_{3.33}Al_{.67}]O_{10}(OH)_2$, respectively. The mobilization of REE appears to occur during illitization. The increase in concentrations of REE, especially La and Ce, with depth is probably linked to incorporation of ions with high valency (e.g. $V^{5+}$) in tetrahedral sites. The excess valency due to V is partly counter-balanced by ions with low valency (e.g. $Be^{2+}$) and, in turn, the local valency deficiency caused by $Be^{2+}$ could be compensated by high-charge interlayer cations such as REE (＋3). ${\delta}^{18}O$ values of I/S range from 2.91 to 15.72‰ (SMOW), and increase with depth, contrasting to trends observed in the Gulf Coast and elsewhere. The increase in ${\delta}^{18}O$ of I/S results from the rapid increase in ${\delta}^{18}O$ of pore water that overcomes the decrease in temperature-dependent fractionation values with increasing burial depth (${\delta}^{18}O_{pore\;water}>-d{\Delta}/_{I/S-water};\;d{\delta}^{18}O_{I/S}>0$). Calculated ${\delta}^{18}O$ values of pore water in equilibrium with I/S suggest that the original water was probably meteoric water. The stratification of pore water is postulated from the presence of an isotopically light interval, about 450m thick. The depth range of the isotopically light zone overlaps, but does not coincide with the interval of lowered I-content and $K_2O$ concentrations, suggesting that oxygens may have been exchanged independently of mineralogical and geochemical reactions.

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