• Title/Summary/Keyword: Rare

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

  • Kim, Youngjin;Kim, Seunghyun;Lee, Jaeryeong
    • 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.

  • https://doi.org/10.7844/kirr.2019.28.6.26 인용 PDF KSCI

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
    • Journal of Bio-Environment Control
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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.

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