• Korean Journal of Poultry Science
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• v.34 no.1
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• pp.23-29
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• 2007

Rare earth(RE) is a common name indicating 17 of specific elements including 15 of lanthanides, scandium (Sc), and yttrium(Y). This study was conducted to compare the effect of RE to growth stimulating antibiotic products in broiler diet. One of the products commonly used in broiler feeding, Chlorotetracycline(CTC) was used at a level of 200ppm for the antibiotic treatment and replaced by 100ppm RE for the RE treatment. Dietary addition of RE and CTC showed similar effects in improving broiler growth and feed conversion each other, and those were significantly better when compared to those of the control group(P<0.05). Abdominal fats of chicks fed RE were significantly lower than others(P<0.05). Intestinal E. coli and total microbial numbers were reduced by RE addition(P<0.05), but the number of Lactobacillus was not affected. The number of Salmonella was also decreased but it was not significant.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.4
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• pp.263-269
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• 2015

It is necessary to investigate the electrodeposition behavior of uranium and other elements on the cathode in the electrorefining process to recover the uranium selectively from the reduced metals of the electrolytic reduction process since transuranic elements and rare earth elements is dissolved in the LiCl-KCl eutectic salt. Study on separation factors of U, Ce, Y and Nd based on U and Ce was performed to investigate the deposition behavior of the cathode with respect to the concentration of rare earth elements in LiCl-KCl eutectic salt. After electrorefining with constant current mode by using Ce metal as a sacrifice anode, the contents of U, Ce, Y and Nd in the salt phase and the deposit phase of the cathode were analyzed, and separation factors of the elements were obtained from the analyses. Securing conditions of pure uranium recovery in the elctrorefining process was investigated by considering the separation factors with respect to $UCl_3$ and $CeCl_3/UCl_3$ ratio.

• The Journal of the Petrological Society of Korea
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• v.14 no.4 s.42
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• pp.237-250
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• 2005

In order to clarify the effect of standard rock material in the chemical analysis of rare earth element abundance with ICP-MS, we measured rare earth element abundance of KIGAM granite standard rock material (KG-1), USGS granite standard rock material (G-2), GSJ granite standard rock materials (JG-1a and JG-2). In REE analysis, we used conventional calibration standard solutions, KG-1, JG-1a, JG-2 and G-2 as standard material, respectively. Chondrite-normalized LREE patterns of low granite standard material correspond well each other in the recommended value and the estimated value regardless of a kind of standard rock. However, the HREE patterns of the estimated value based on G-2 or JG-2 and the recommended value are different from each other. Such difference may be due to the wrong recommended value or a specific geochemical properly of the standard rock material itself, The chondrite-normalized REE patterns of four standard rock materials estimated on the basis of KG-1 or JG-1 a show little deviation compared to the those of the recommended values. This suggests that KG-1 and JG-1a may be a optimum standard material for granitoids.

• Resources Recycling
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• v.29 no.3
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• pp.61-74
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• 2020

This study was conducted to improve the recycling process of waste fluorescent lamp, and investigate the possibility of using the waste fluorescent lamp glass as a raw material for glass beads, the leaching method of rare earth from the waste phosphor powder, and the possibility of solvent extraction of rare earth from the rare earth leaching solution. The waste phosphor contained 28.9% yttrium oxide, 3.46% cerium oxide, 1.95% europium oxide, 1.76% terbium oxide, and 1.43% lanthanum oxide. As a result of the trial production of glass beads using waste fluorescent lamp glass, it was judged that the production yield and quality were excellent, so that waste fluorescent lamp glass could be used as a raw material for glass beads. The soda roasted waste phosphor was leached in water and thereby the aqueous solution was blown with CO₂ to drop the pH to about 7, Then, Al, Si and residual N₂CO₃ were dissolved, and NaAlCO₃(OH)₂ and SiO₂ were precipitated in the aqueous solution. In the solvent extraction of cyanex272-hydrochloric acid, cyanex272-sulfuric acid, D2EHPA-hydrochloric acid, D2EHPA-sulfuric acid, Ionquest290-hydrochloric acid, Ionquest290-sulfuric acid, p507-hydrochloric acid using xylene as a diluent, the extraction yield of Y, Eu, Ce, La, and Tb are close to 100%. However, in this conditions, the difference in extraction yield for each element, that is, selectivity is 16% or less.

• Food Science of Animal Resources
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• v.29 no.6
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• pp.685-694
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• 2009

The aim of the present study was to evaluate the variation in ultimate pH of commercial populations of pure-breed (Landrace, Duroc and Yorkshire) pig's longissimus muscles and their effect on objective meat quality traits and sensory characteristics. Fifty boars were sampled from 184 pigs, which were reared at three breeding farms and slaughtered at a commercial abattoir. The selection was determined based on ultimate pH, and animals were segregated into three groups: low pH (pH $\leq$ 5.5, n=13), medium pH (pH 5.5 to 5.6, n=18) and high pH (pH $\geq$ 5.6, n=16). The breeds had no significant effects; however, pigs with a higher ultimate pH had significantly (p<0.05) higher intramuscular fat content, lower level of polyunsaturated fatty acids, lower level of lipid oxidation and higher eating quality compared to those with lower ultimate pH. As the ultimate pH increased, the relative proportion of C14:0, C16:0 and C18:1 increased while C18:2n6 and C20:4n6 decreased. The present study demonstrates that the economic value of pigs can be characterized by the ultimate pH and/or intramuscular fat content. However, these results do not necessarily indicate that a high ultimate pH directly corresponds to high intramuscular fat content and vice versa.

• Resources Recycling
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• v.26 no.5
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• pp.39-47
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• 2017

In this study, the precipitation of rare earth-sodium sulfate with sodium sulfate was conducted in order to separate rare earth from Fe in rare earth sulfate solution. Neodymium (Nd) was easily precipitated as Nd-sulfate salt with sodium sulfate, on the other hand, excessive sodium sulfate was needed for the precipitation of Dy-sulfate salt. Also neodymium not only promoted the precipitation of dysprosium sulfate salt but also increased recovery of dysprosium sulfate salt in sulfuric acid solution. At the condition of $60^{\circ}C$ precipitation temperature, 3 h reaction time, 7 equivalents sodium sulfate, the recovery of neodymium and dysprosium sulfate salt was 99.7% and 94.3% respectively from the sulfuric acid solution containing Nd of 23.39 mg/ml and Dy of 8.67 mg/ml. Lastly, from the results of separation of Dy to Nd by the method of sulfate double salt, the effect of salting out with NaCl is important to increase the grade of Dy, and 98.7% of Dy grade could be obtained in this study.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.194-195
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• 2003

High-pressure amphibolite-facies rocks with serpentinized ultramafic rocks occur in the Gyeonggi Massif. Ultramafic rocks occur as lenses within Precambrian granite gneiss, which showing dominantly tectonic lines of NNE directions as well as east extensional area of the chinese collision belt between south and north China block(\ulcorner). This study regionally makes a comparative study of ultramafic rocks in the western part of the Gyeonggi Massif in Korea. (omitted)

• Journal of the Korean Chemical Society
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• v.41 no.11
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• pp.612-638
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• 1997

The methods of separation and recovery of rare earth elements in monazite sand have been studied by the ion exchange chromatography. Both of cation and anion exchange resin were used as ion exchange resins and the solutions of EDTA, DTPA, IMDA and Ln-EDTA were used as eluents. The H+, Zn2+, Fe3+, Al3+, Cu2+, and NH4+ forms of cation exchange resin were used as retaining ions. Ln-EDTA solution was loaded on the EDTA form of anion exchange resin and separated. The Ln-EDTA solution was also used as an eluent for a selective separation of one element from the rare earth mixture solution. The size effects of resin column, the elution mechanism for the various elution types and the separation of a large amount of rare earths were studied.

• Resources Recycling
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• v.30 no.2
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• pp.31-38
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• 2021

To investigate the separation of La(III) from sulfuric acid solutions containing Fe(III), rare earth double salt precipitation experiments were performed by adding sodium sulfate. In this work, the effect of sodium sulfate, Fe(III), and La(III) concentrations; reaction temperature; and time was investigated. The extent of precipitation of La(III) was proportional to the concentrations of Na+ and SO42- in the solution. As the reaction temperature increased to 100 ℃, the extent of precipitation of La(III) increased. The extent of precipitation of Fe(III) decreased with increasing reaction time. The concentration ratio of Fe(III) to La(III) did not have a significant effect on the precipitation of La(III). Our results indicate that it is possible to separate La(III) from a ferric sulfate solution through selective precipitation by adding sodium sulfate.

• Korean Journal of Metals and Materials
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• v.56 no.12
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• pp.870-877
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• 2018

Cyanex 272 shows the highest separation factor for the rare earth elements from hydrochloric acid solution among the organophosporus acidic extractants, D2EHPA and PC 88A. Solvent extraction of Tb(III) from weak hydrochloric acid solution with an initial pH 3 to 6 was compared with Cyanex 272, its mixture with Alamine 336, and ionic liquid with Aliquat 336. The solvent extraction reaction of Tb(III) using Cyanex 272 was the same as that of light rare earth elements. Synergism was observed for the extraction of Tb(III) by the mixture with Alamine 336 when the initial concentration ratio of Cyanex 272 to Alamine 336 was higher than 5. Use of the ionic liquid led to a great increase in the extraction percentage of Tb(III) from the same initial extraction conditions. While the equilibrium pH of the mixture was always lower than the initial pH, under some conditions extraction with the ionic liquid resulted in a higher equilibrium pH than the initial pH. The loading capacity of the mixture and the ionic liquid was the same and 2.6 times larger than that using Cyanex 272 alone. Ionic liquid was recommended as a suitable extractant for the extraction of Tb(III) from hydrochloric acid solution based on the ease of handling and higher extraction percentage.