• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.1
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• pp.45-57
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• 2014

Academic interests in ionic liquid (IL) technologies have been extended to the nuclear industry and the applicability of ionic liquids for processing radioactive materials have been investigated by many researchers. A number of studies have reported interesting results with respect to the spectroscopic and electrochemical behaviors of metal elements included in spent nuclear fuels. The measured and observed properties of metal ions in TBP(tri-butyl phosphate) dissolved ILs have led the development of alternative technologies to traditional aqueous processes. On the other hand, the electrochemical deposition of metal ions in ILs have been investigated for the application of the solvents to aqueous as well as to non-aqueous processes. In this work, a review on the application of ILs in nuclear fuel cycle is presented for the purpose of categorizing and summarizing the notable researches on ILs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.438-445
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• 2017

Tanzania has abundant copper deposits, but copper-metal extraction remains low there, owing to the lack of suitable copper recovery processes and insufficient funds for developing mining technologies. Accordingly, leaching and solvent extraction methods for the extraction of copper from copper ore were studied with a particular emphasis on developing a simple processing method for small-scale copper mining. Chrysocolla ore was used as the copper-bearing mineral and sulfuric acid was used as the leaching reagent. A maximum copper recovery of 95.1% was obtained when the particles in the sample were smaller than $53{\mu}m$, the concentration of 98%(w/w) sulfuric acid in the leaching solution was 5.0 g/L and the stirring rate was between 60 and 80 rpm. The highest selectivity of $Cu^2+$ in the solvent extraction was obtained using 15% LIX-70 in kerosene. In the pH range from 0.5 to 3.0, the efficiency of $Cu^2+$ extraction increased with increasing pH. However, at pH values higher than 3.0, other metal ions were extracted into the organic phase more readily than $Cu^2+$. The highest solvent extraction rate obtained was 96.5% at pH values of 2.0 and 3.0 using 15% LIX-70.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.245-256
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• 2004

The extraction of three kinds of amido podands, N,N,N'N'-tetrabutyl-3-oxa-pentanedi- amide (TBDGA), N,N,N'N'-tetra-isobutyl-3-oxa-pentanediamide(TiBDGA) and N,N,N'N'-tetra- butyl-3,6-dioxa-oct-anediam- ide(TBDOODA) on U(VI),Pu(IV), Am(III), Eu(III) and other metal ions is studied in nitric acid solutions. 40%octanol-kerosene is chosen as diluents to eliminate third phase and emulsion. TBDGA and TiBDGA show extraction selectivity to An(III) and Ln(III) much higher than to U(VI) and Pu(IV). Fe, Ru and Mo is poorly extracted by the three kinds of amid podands in 2~3mol/L $HNO_3$ solutions. Aiming to eliminate interface crude when using simulated HLLW solution in the system of 0.2mol/L TBDGA/Octanol＋kerosene, acetohydroxyamic acid was adapted. Distribution ratio of zirconium was decreased when adding acetohydroxyamic acid in aqueous solution, and interface crude disappeared as mixing extractant with HLLW. The counter-current extraction test is carried out in a set of miniature mixer-settler, with 0.2mol/L TBDGA/ 40% octanol-kerosene as extractant to separate U(VI), Pu(IV), Am(III) and Eu(III) from simulated high level liquid waste(HLLW) solution. In battery A, lanthanides and actinides are coextracted into organic phase with the recovery of 99.98% for U(Ⅵ), >99.99% for Pu(IV), and >99.99% for Am(III) and Eu(III) respectively. In battery R1, 99.99% U, 86.2% Pu and a part of Am or Eu are stripped into aqueous phase by 0.2mol/L acetohydroxyamic acid (AHA) in 0.01mol/L $HNO_3$ solution. In battery $R_2$, Am, Eu and remained Pu are completely back-extracted by 0.2mol/L AHA. This separation process contains no salt reagent, and it is not necessary to dilute HLLW feed.

• Resources Recycling
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• v.32 no.1
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• pp.21-32
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• 2023

Because the application of lithium has gradually increased for the production of lithium ion batteries (LIBs), more research studies about recycling using solvent extraction (SX) should focus on Li⁺ recovery from the waste solution obtained after the removal of the valuable metals nickel, cobalt and manganese (NCM). The raffinate obtained after the removal of NCM metal contains lithium ions and other impurities such as Na ions. In this study, we optimized a selective SX system using di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the extractant and tri-n-butyl phosphate (TBP) as a modifier in kerosene for the recovery of lithium from a waste solution containing lithium and a high concentration of sodium (Li⁺ = 0.5 ~ 1 wt%, Na⁺ = 3 ~6.5 wt%). The extraction of lithium was tested in different solvent compositions and the most effective extraction occurred in the solution composed of 20% D2EHPA + 20% TBP + and 60% kerosene. In this SX system with added NaOH for saponification, more than 95% lithium was selectively extracted in four extraction steps using an organic to aqueous ratio of 5:1 and an equilibrium pH of 4 ~ 4.5. Additionally, most of the Na⁺ (92% by weight) remained in the raffinate. The extracted lithium is stripped using 8 wt% HCl to yield pure lithium chloride with negligible Na content. The lithium chloride is subsequently treated with high purity ammonium bicarbonate to afford lithium carbonate powder. Finally the lithium carbonate is washed with an adequate amount of water to remove trace amounts of sodium resulting in highly pure lithium carbonate powder (purity > 99.2%).

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.713-717
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• 2006

$S_2O$-donor macrocyclic isomers incorporating a xylyl group in o- ($L^1$), m- ($L^2$) and p-positions ($L^3$) extract no metal ions except silver(I) from aqueous to chloroform phase. And the magnitudes of %Ex for silver(I) are in the order of $L^1$ > $L^2$ > $L^3$. Taking this result into account, $L^1$-$L^3$ were utilized as membrane active components to prepare potentiometric silver(I)-selective electrodes. The proposed macrocycles-based electrodes E1 ($L^1$), E2 ($L^2$) and E3 ($L^3$) exhibited comparable results which show considerable selectivity toward silver(I) over alkali, alkali earth and other transition metal ions. Comparative NMR study on $L^1$-$L^3$ and their complexes with silver(I) in solution was also accomplished. In addition, a unique sandwich-type complex $[Ag(L^1)_2]CIO_4$ was prepared from the assembly reaction of $L^1$ with $AgClO_4$ and structurally characterized by an X-ray diffraction analysis.

• Resources Recycling
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• v.3 no.2
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• pp.17-23
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• 1994

The dissolution of gold and silver from concentrate was studied with acidic thiourea solution. The results showed that the gold and silver extraction was severely affected by concentration of thiourea and oxidant, pulp density, etc. Especially, oxidant such as ferric ions enhanced the leching rate of gold and silver. High concentration of ferric ions, however, dissolved the sulfide ore to form electrochemically passive layer on the surface of ore particles, which caused the precious metal not to be leached out from the ore. The use of $SO_2$could not effectively enhance the recovery of precious metal but reduce to some extent the consumption of thiourea. The leaching of gold and silver was achieved with recovery more than 90% and 80%, respectively, under the following conditions; Thiourea conc. :0.4M Oxidant : None $H_2SO_4$ conc. : 0.5M Pulp density : <10% Leaching time :4 Hrs Potential :250mV The Thiourea was consumed about 10% in comparison with its initial concentration.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.54-59
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• 2003

Several radionuclides are considered as an object of the assesment to develop a scaling factor and a periodical verification method which are needed for the evaluation of radionuclide inventory of various radioactive wastes from nuclear power plants in Korea. A selective separation of $^{55}Fe$, $^{90}FSr$ 및 $^{94}Nb$ which should be recovered individually for the radiochemical analysis was described in detail. Sorption and desorption behaviours of ion exchange and extraction chromatographic resins for Fe, Sr, Nb and co-existing metal ions were Investigated using an artificial waste solution simulated of chemical composition of real radioactive wastes. Separation conditions available for the sequential recovery of these metal ions from a single sample were optimized to minimize a discharge of radioactive wastes produced through the analytical process and a radiation exposure to analysts. Their recovery yields were measured with reliability.

• Analytical Science and Technology
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• v.8 no.3
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• pp.321-334
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• 1995

Basic studies for the effective extraction of ammonium pyrrolidine dithiocarbamate(APDC) complexes of Co(II), Ni(II) and Cu(II) into a solvent have been performed. The maximum distribution ratio was appeared (log D=1.3543) at pH 2.0 and the partition coefficient was 2.489 in the extraction of $4{\times}10^{-5}M$ APDC itself into chloroform. From the UV/visible spectra of metal-chelates in aqueous and organic solutions, the pH to form stable 1:2 metal-ligand complexes were Co(II):5.0, Ni(II):8.0 and Cu(II):8.0, respectively and only 1 minute was enough to be partitioned into the chloroform. Besides, the partition and extraction equilibria of the complexes were investigated by back-extracting $10.0{\mu}g/ml$ metal-chelates from the solvent into an aqueous solution beacuse of their slight solubilities in the aqueous solution. The distribution coefficients and extractabilities were as follows : at pH 6.5~8.5 of the aqueous solution, log D=2.834 : E(%)=99.9% for $Co(PDC)_2$, at pH 11, log D=5.699 E%=100 for $Ni( PDC)_2$, and at pH 6.0, log D=2.025 : E(%)=99.1% for $Cu(PDC)_2$. And the extraction and formation constants were log $K_{ex}=9.671$ : log ${\beta}_2=6.938$ for $Co(PDC)_2$, log $K_{ex}=9.646$ : log ${\beta}_2=7.071$ for $Ni( PDC)_2$, and log $K_{ex}=9.074$ : log ${\beta}_2=7.049$ for $Cu(PDC)_2$, respectively. From these results, an optimum extraction procedure can be constructed for the separative concentration of trace metallic ions, and the quantitative determination of them in advanced materials and environmental samples will be expected without any influence of sample matrixes.

• Korean Journal of Pharmacognosy
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• v.42 no.1
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• pp.68-75
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• 2011

A new lectin was purified from Bombyx mori (BML) by physiological saline extraction, ammonium sulfate precipitants, anion exchange column chromatography on DEAE Sephadex A-50 and gel filtration column chromatography on Sephadex G-200. BML agglutinated trypsinized and glutaraldehyde-fixed erythrocytes, and was observed the most high activity with rabbit, chicken erythrocytes and rat splenic lymphocytes. Agglutinability was markedly affected at highly acidic pH, but was relatively stable with high temperature. The effect of metal ions was observed and BML was affected by bivalaent cations, especially depending on $Ca^{2+}$, $Fe^{2+}$, $Mn^{2+}$, whereas, inhibited by $Mg^{2+}$. Agglutination was strongly inhibited by heparin and glucuronic acid. BML was proved to be a glycoprotein which contains 17.16% of sugars. By mass spectrometry analysis, we found 2 bands that were considered as lectin subunits.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.444-455
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• 1991

Two kinds of new lectin fractions (LOA-I, LOA-II) were obtained from loach (Misgurnus spp.) meat by 0.15 M NaCl extraction, salt fractionation, ion exchange and hydroxyapatite column chromatographies. On polyacrylamide gel electrophoresis, LOA-I exhibited one major and a few minor bands, but LOA-II exhibited three minor bands. The partially purified loach lectins agglutinated not only erythrocytes of human B and AB type, rabbit, dog, but also murine splenic lymphocytes. Agglutinability was relatively labile at various pH and stable at increasing temperature, but was not affected by tested several metal ions. By the sugar specificity test, D-glucosamine and metyl-$\beta$-galactopyranose inhibited agglutinating activity at a final concentration of 3 mM. The lectins contained relatively high amounts of aspartic acid, valine and leucine, but sulfur containing amino acids, cystein, methionine and isoleucine were not determined. LOA-I, LOA-II lectins were nonmitogenic toward murine lymphocytes.