• Title, Summary, Keyword: Rare Earth Elements

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Study on the Ion Exchange Mechanisms of Rare Earth Elements in Several Elution Types (II) (희토류원소의 여러 가지 용리형태의 이온교환 메카니즘에 관한 연구 (II))

  • Ki-Won Cha;Sung Wook Hong
    • Journal of the Korean Chemical Society
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    • v.35 no.5
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    • pp.553-559
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    • 1991
  • The elution characteristics of rare earth elements in $NH^{4+}$ form cation exchange resin had been investigated. Elution were performed varing the loading amount, column diameter, column length and eluent pH. Analysing the chemical species contained in each effluent, elution mechanisms of rare earth elements and the separation of rare earth elements in monazite could be understood. The resolution values of adjacent rare earth elements were improved increasing rare earths adsorption amount wfith the same column within it's exchange capacity. With $NH^{4+}$ resin form, column length does not affect on the resolution values and retention time of rare earth elements and the rare earth-EDTA complex were not adsorbed on $NH^{4+}$ resin form. pH of eluent affected on the reactivities between rare earth elements and EDTA. Decreasing eluent pH, resolution values of adjacent rare earth elements were increased while increasing elution time.

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Correlation between rare earth elements in the chemical interactions of HT9 cladding

  • Lee, Eun Byul;Lee, Byoung Oon;Shim, Woo-Yong;Kim, Jun Hwan
    • Nuclear Engineering and Technology
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    • v.50 no.6
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    • pp.915-922
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    • 2018
  • Metallic fuel has been considered for sodium-cooled fast reactors because it can maximize the uranium resources. It generates rare earth elements as fission products, where it is reported by aggravating the fuel-cladding chemical interaction at the operating temperature. Rare earth elements form a multicomponent alloy (Ce-Nd-Pr-La-Sm-etc.) during reactor operation, where it shows a higher reaction thickness than a single element. Experiments have been carried out by simplifying multicomponent alloys for mono or binary systems because complex alloys have difficulty in the analysis. In previous experiments, xCe-yNd was fabricated with two elements, Ce and Nd, which have a major effect on the fuel-cladding chemical interaction, and the thickness of the reaction layer reached maximum when the rare earth elements ratio was 1:1. The objective of this study is to evaluate the effect and relationship of rare earth elements on such synergistic behavior. Single and binary rare earth model alloys were prepared by selecting five rare earth elements (Ce, Nd, Pr, La, and Sm). In the single system, Nd and Pr behaviors were close to diffusion, and Ce showed a eutectic reaction. In the binary system, Ce and Sm further increased the reaction layer, and La showed a non-synergy effect.

Studies on the Stability constants of complexes between rare earth elements and ethylenediaminediacetic acid (몇가지 희토류원소와 Ethylenediaminediacetic acid간의 착물의 안정도상수 측정)

  • Cha, Ki-Won;Hyun, In-Seong;Choi, Hyun-Chol
    • Analytical Science and Technology
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    • v.14 no.4
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    • pp.371-375
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    • 2001
  • The stability constants of complexes between rare earth elements(Yb, Dy, Sm, Nd, Pr, Ce, La) and ethylenediaminediacetic acid(EDDA) have been measured for the separation of rare earth elements by potentiometric method. The $pk_1s$ of $MA^+$ complexes are in the range of 8.80-6.72 and the $pk_2s$ of $MA_2^-$ complexes are in the range of 7.43-4.37. The magnitude sequences of the stability constants are the reverse of the ionic size of rare earth elements.

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The Accumulation of Rare Earth Elements Fertilizer and its Subsequent Effects on Apple Fruit Quality at Harvest and During Storage (희토류비료 시비가 사과 과실내 축적과 수확 및 저장 중 사과품질에 미치는 영향)

  • Zheng, Wei-Wei;Park, Mu-Young;Hirst, Peter;Yoon, Tae-Myung;Chun, Ik-Jo
    • Protected Horticulture and Plant Factory
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    • v.21 no.4
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    • pp.452-458
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    • 2012
  • Rare earth elements fertilizer and Ca were sprayed on eight-year-old 'Fuji'/M.9 apple trees during two consecutive seasons, and fruit quality was quantified at harvest and 5-month long storing in a commercial cooling house at $4^{\circ}C$ and 80~85% RH. In the first season, single-sprayed of rare earth elements fertilizer showed appreciable accumulations of its elements (La, Pr, Gd, and Nd) in the fruit. In the following season, application of higher doses accumulated higher amount, indicating that the accumulation of rare earth elements was dose-dependent. However, rare earth elements did not affect the accumulations of Ca, Mg, and K in 'Fuji' apple fruit showed that there was no interaction between rare earth elements and these macronutrients. Double-spray of 0.2% rare earth elements increased fruit redness at harvest and had exhibited better color. Although at harvest it did not show significant effects on fruit weight, pulp firmness and titratable acidity (TA), but had pronounced effects on inhibiting fruit softness and retarded decrease of TA during storing. Furthermore, it reduced respiration rate and inhibited ethylene production during storing indicated that rare earth elements may be an alternative for prolonging the shelf life of 'Fuji'/M.9 apple fruit.

Solvent Extraction of Light (Pr, Nd) and Medium (Tb, Dy) Rare Earth Elements with PC88A of Rare Earth Chloride Solution from Waste Permanent Magnet (폐 영구자석으로부터 회수한 염화희토류용액에서 PC88A를 이용한 경희토류(Pr, Nd)/중희토류(Tb, Dy) 용매추출)

  • Jeon, Su-Byung;Son, InJoon;Lim, Byung-Chul;Kim, Jeong-Mo;Kim, Yeon-Jin;Ha, Tae-Gyu;Yoon, Ho-Sung;Kim, Chul-Joo;Chung, Kyeong-Woo
    • Journal of the Korean Institute of Resources Recycling
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    • v.27 no.3
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    • pp.8-15
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    • 2018
  • Solvent extraction behavior of light rare earth elements (Pr, Nd) and medium rare erath elements (Tb, Dy) in the HCl-PC88A-kerosene extraction system was investigated in order to separate high-purity light rare earths (Pr, Nd) and medium rare earths (Tb, Dy) in the mixed rare earth chloride solution. In the batch test step, it was confirmed that the separation efficiency was good when the extractant concentration (PC88A) was 0.5 M, the equilibrium pH after extraction was 0.8 to 1.0 (initial pH 1.3 of the feed), the concentrations of hydrochloric acid in scrubbing solution was set as 0.1 M, the concentrations of hydrochloric acid in stripping solution was set as 2.0 M or more. Based on the experimental data obtained from the batch test, the mixer-settler was composed as follows; 4 stages of extraction, 8 stages of scrubbing, 4 stages of stripping, and 3 stages of pickling organic solution. The Mixer-settler was operated for 180 hours, and the operating conditions were continuously adjusted to obtain the high-purity light/medium rare earths. Finally, the purity of light (Pr, Nd) and medium rare earth elements (Tb, Dy) was reached as 3 N class.

The Elution Behavior of Rare Earth Elements in Diethylene Triamine N,N,N',N',N (陰 Ion 交換樹脂에 依한 稀土類元素의 溶離行動에 關한 硏究)

  • Oh Jin Jung;Il Doo Kim;Gyou Soo Lee;Ki-Won Cha
    • Journal of the Korean Chemical Society
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    • v.28 no.1
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    • pp.47-53
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    • 1984
  • The separation of the rare earth elements with diethylene triamine N, N, N', N', N"-pentaacetic acid (DTPA) as eluent was carried out at different pH and concentrations by using anion exchange resin column. The rare earth elements were absorbed on the upper of the resin column and the best condition of the separation behavior was 0.025M of DTPA at pH 8.35. The elution order of the rare earths was in the order of the atomic number of the rare earth elements except samarium. The resolution of adjacent rare earth elements that have been separated with 0.025M-DTPA as eluent, was from 3.03 to 1.25 at pH 8.35. Resolution of Ce-Pr was maximum value in 3.03 and Eu-Gd was minimum in 1.25 at condition mentioned above, respectively. The resolution of rare earth elements separated with 0.025M DTPA eluent was very good at pH range of 8.0~8.6.

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Separation of Light Rare Earth Elements by Solvent Extraction with a Mixture of Cationic and Tertiary Amine (양이온 추출제와 아민의 혼합추출제에 의한 경희토류금속의 분리)

  • Lee, Man-Seung;Son, Seong Ho
    • Journal of the Korean Institute of Resources Recycling
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    • v.26 no.2
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    • pp.3-10
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    • 2017
  • Rare earth elements with high purity are demanded for the manufacture of advanced materials. Light rare earth elements are contained in domestic monazite and Ni-MH batteries. In this paper, solvent extraction to separate the light rare earth elements from hydrochloric acid leaching solutions of these resources was discussed. A mixture of cationic and tertiary amine shows synergistic effect on the extraction of LREEs and the extent of pH decrease during extraction is reduced. The effect of solution pH on the extraction and synergism was reviewed. Acquisition of the operation data with mixer-settler on the separation of LREEs by this mixture is necessary to develop a process.

Economic Evaluation of Rare Earth Elements Contained in Coal Ash (석탄재에 포함된 희토류의 경제성 평가)

  • Kim, Youngjin;Kim, Seunghyun;Lee, Jaeryeong
    • Journal of the Korean Institute of Resources Recycling
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    • v.28 no.6
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    • pp.26-35
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    • 2019
  • This study aims to introduce and economical review on the possibilities of rare earth elements(REEs) recovery from coal ashes and the analysis of economical evaluation factors based on the data for securing domestic rare earth elements. The cut-off grade of REEs on recovering from coal ash was confirmed to be 1,000 ppm on total rare earth oxides(TREO) basis, and while the economic value of coal ash changed with contents and specific elements of rare earth elements. This shall be resulted in the price differences of rare earth elements required by the current industry, and it probably varies depending on the future demand of rare earth components. For developing of commercial recovery technology on REEs in coal ashes, many researches have been carried out by various analyzing methods, such as evaluation of holding value of REEs in ashes, assessment between supply and demand of industry, comparison of investment and its profitability for the REEs's production from coal ashes, and so on. Although these methods have been suggested, its recovery system with economical feasibility could not been confirmed up to present. In this reason, the process design of recovering REEs from coal ash shall be researched continuously to solve the problems of the global rare earth market. And also these researches shall be conducted actively in Korea for the purpose of securing the REEs resources and their recovering technologies.

Study on the Elution Behavior of Rare Earth Elements by Cation Exchange Resin (양이온 교환수지에 의한 희토류 원소의 용리현상에 관한 연구)

  • Ki-Won Cha;Sung-Wook Hong;Kyung-Hwan Kim
    • 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.

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Effect of Addition Elements on the Production of the 2-17 Type High Performance of the Rare Earth Permanent Magnet Materials by the Reduction and Diffusion Process (환원·확산법에 의한 2-17형 고성능 희토류영구자석 재료의 제조에 있어서 첨가원소의 영향)

  • Song, Chang-Been;Cho, Tong-Rae
    • Journal of the Korean Society for Heat Treatment
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    • v.8 no.4
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    • pp.333-339
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    • 1995
  • The reduction and diffusion process(R-D process) is an economical way to produce the functional materials which contain rare-earth elements and has been applied to the production of rare-earth magnet meterials($SmCo_5$, $Nd_{15}Fe_{77}B_8$), magneto-optical(MO) target materials and hydrogen storage alloy, etc. However, because of difficult to control of the final composition, the R-D process has not been applied to production of the 2-17 type rare earth permanent magnet materials which contain several elements. Therefore, this work was as a basic study for the production of the 2-17 type rare earth permanent materials with composition $Sm(Co_{0.72}Fe_{0.21}Cu_{0.05}Zr_{0.03})_{7.9}$ by the R-D process, the following were mainy examined ; the amount of metallic calcium as a reductant, homogenization condition of the alloy after the R-D reaction, masuring of magnetic properties of the sample after step aging. The sample prepared by the R-D process contained a little more oxygen than that prepared by the melting method, however, showed almost the same magnetic properties.

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