• 제목/요약/키워드: p-LEACH

검색결과 48건 처리시간 0.028초

The Leaching Behavior of Unirradiated $UO_2$ Pellets in Wet Storage and Disposal Conditions

  • Park, Geun-Il;Lee, Hoo-Kun
    • Nuclear Engineering and Technology
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    • 제28권4호
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    • pp.349-358
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    • 1996
  • The leaching behavior of uranium from unirradiated CANDU UO$_2$ fuel pellet in the spent fuel wet storage and disposal conditions has been investigated. A modified IAEA leach test method was used, and then the extent of leaching was monitored by analysis for uranium in the leachant. The leach test has been performed in various leachants(demineralized water and boric acid solution at pH=6, synthetic granite groundwater) for a long-term period of 5.4 years, and the effect of temperature on the leach rate of uranium has been analyzed. The leach rates of uranium at $25^{\circ}C$ were dependent on the leachants. Over initial 100 days of leach periods, the leach rate in groundwater was the highest in three leachants and no significant differences of leach rates ore observed in the demineralized oater and boric acid solution. But these leach rates in three leachants around 2,000 days at $25^{\circ}C$ appeared to be reached the steady rates in the range of 1~5$\times$10$^{-8}$ g/$\textrm{cm}^2$ day. The leach rate of uranium in groundwater shooed to be independent of the temperature, but those in both demineralized water and boric acid solution increased with temperature. These results show that the leaching behavior of uranium from UO$_2$ fuel in both the demineralized water ann boric acid may be controlled tv the surface oxidative.dissolution reaction of UO$_2$ and the leach rate of uranium in groundwater at room temperature could mainly be controlled by the complex reaction of dissolved uranyl ions with carbonate ions and no variation of leach rate of UO$_2$ in groundwater with temperature may be due to the local deposition of passivating uranyl phases on the surface.

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UV 분광법을 이용한 중유회 용출액으로부터 바나듐의 선택적 회수 조건 (A Selective Recovery Condition of Vanadium from Fly Ash Leach Liquor by UV-Spectrophotometry)

  • 김다빈;나수빈;한혜철
    • 자원리싸이클링
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    • 제25권6호
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    • pp.65-72
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    • 2016
  • 중유 화력발전소에서 발생되는 중유회를 처리한 용출액(Fly Ash Leach Liquor; FALL)으로부터 V을 선택적으로 회수하기 위한 기초 연구를 UV 분광법을 이용해 수행하였다. Ni, Fe등이 포함된 시료를 분광법으로 V을 정량할 때, Ni, Fe등의 금속이 V 정량에 미치는 범위를 조사하였고 FALL 시료에 5.0M $NH_3$ 사용량과 pH 변화에 따른 금속의 침전율과 교반시간에 따른 금속 침전율의 최적 조건을 조사하였다. $25^{\circ}C$, pH 7.0 (5.0M $NH_3$)에서 선택적인 V의 회수 시점은 교반 시간이 1분 이내일 때로 91.5%의 회수율을 보였다.

잎들깨의 플러그육모에서 용탈률 및 시비농도가 생육 및 무기원소 흡수에 미치는 영향 (Effect of Nutrient Concentrations and Leaching Percentage on Growth and Nutrient Uptake by Perilla Frutesens Britton var. Japonica Hara in Plug Culture)

  • 최종명;윤화모;박종윤
    • 자연과학논문집
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    • 제13권1호
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    • pp.83-96
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    • 2003
  • Effect of Nutrient Concentrations, fertigation frequency, and learching percentage on crop growth and nutrient concentrations in root media were evaluated. The treatment of each irrigation with $50 mg.L^{-1}$ of nitrogen in stage 2 and increase to $80 mg.L^{-1}$ nitrogen in stage 3 had the highest crop growth at 34 days after sowing among treatments tested. Feeding with low nutrient concentrations and elevated frequency decreased crop growth. In treatments of each leaching percentage, feeding with low nutrient concentrations and elevated frequency resulted in increased tissue nutrient contents. The less tissue potassium content and higher calcium and magnesium contents were observed in treatment of 50% leach than those in 0% leach. All treatment tested had soil solution pH higher than 6.8. Electrical conductivity in treatments of 50% leach were lower than those of 0% leach. Feeding with low nutrient concentrations and elevated feeding frequency in each leaching percentage resulted in increased electrical conductivity in soil solution of root media. Trends of medium nutrient concentrations were similar to those of electrical conductivity.

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Clustering Algorithms for Reducing Energy Consumption - A Review

  • Kinza Mubasher;Rahat Mansha
    • International Journal of Computer Science & Network Security
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    • 제23권7호
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    • pp.109-118
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    • 2023
  • Energy awareness is an essential design flaw in wireless sensor network. Clustering is the most highly regarded energy-efficient technique that offers various benefits such as energy efficiency and network lifetime. Clusters create hierarchical WSNs that introduce the efficient use of limited sensor node resources and thus enhance the life of the network. The goal of this paper is to provide an analysis of the various energy efficient clustering algorithms. Analysis is based on the energy efficiency and network lifetime. This review paper provides an analysis of different energy-efficient clustering algorithms for WSNs.

The Effects of pH and Buffer Materials on the Leaching of Simulated Waste Glass

  • Kim, S.S.;Kim, J.G.;Kim, J.S.;Chun, K.S.;Lee, G.H.
    • Nuclear Engineering and Technology
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    • 제30권1호
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    • pp.1-7
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    • 1998
  • Effects of pH, bentonite and Portland cement on the leaching of the simulated waste glass were investigated. The simulated waste glass showed the low leach rate in the neutral pH region, while the leach rate in both acidic and alkaline regions increased. Addition of bentonite to the leachant enhanced the leaching of the waste glass. When the waste glass was leached at 72$^{\circ}C$ for 36 days in the ground water with gel state Na-bentonite, approximately 2.2${\mu}{\textrm}{m}$ of the surface was corroded out and the large amount of Ti, Nd, and Zr was observed on the surface. The amount of B leached from the simulated waste glass in the presence of domestic bentonite was about three times higher than that in the presence of Aldrich bentonite as well as Portland cement.

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합성무기복합체 조성변화에 따른 모의 LiCl 염폐기물의 탈염소화/고형화 (Dechlorination/Solidification of LiCl Waste by Using a Synthetic Inorganic Composite with Different Compositions)

  • 김나영;조인학;박환서;안도희
    • 방사성폐기물학회지
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    • 제14권3호
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    • pp.211-221
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    • 2016
  • 파이로 공정에서 발생되는 염폐기물은 휘발성이 높아 고온공정에 적용하기 어려우며, 폐기물내에 존재하는 염소로 인해, 전통적인 유리매질에 대한 상용성이 낮은 특성을 가지고 있어, 새로운 고화방법이 필요하다. KAERI에서는 탈염소화법을 이용하여 염소를 탈리하고, 일반적인 유리매질에 고화하는 연구방법을 제안하였다. 본 연구에서는 기존의 탈염소화법에 사용된 합성무기복합체(SAP, $SiO_2-Al_2O_3-P_2O_5$)에 첨가물로서, $Fe_2O_3$$B_2O_3$를 부가하여 5성분계의 복합체를 제조하고, 조성에 따른 탈염소화반응 및 고화체의 특성을 조사하였다. 탈염소화 반응은 조성에 따른 생성물의 변화 경향은 크지 않았으며, 유사한 반응메커니즘으로 주어진 시간 내에 반응이 진행되는 것으로 나타났다. Si-rich phase와 P-rich phase를 화학적으로 연결시켜주는 $Al_2O_3$$B_2O_3$의 함량이 높은 경우에는 고화체내 상분리의 정도는 상대적으로 낮게 나타나며, 구성원소의 분포가 보다 균일한 형태를 보였다. PCT-A 침출시험법을 통한 조성에 따른 내구성의 평가결과, 기준조성을 벗어나는 경우에는 내침출성이 낮게 나타났으나, EA glass(Environmental Assessment glass)의 값보다는 우수한 것으로 확인되었다. 이상의 결과로 부터, 주어진 적정 Si와 P의 조성분율하에서, Al과 B의 함량변화는 고화체의 미세구조와 내침출성에 영향을 주는 것을 확인할 수 있었으며, 미세구조와 내침출성의 연관관계에 대한 추가적인 연구가 필요할 것으로 판단된다.

산침출에 의한 광미중 비소성분의 제거에 관한 연구 (A Study on the Removal of Arsenic 1mm Closed-Mine Tailings by Acid-Leaching Process)

  • 오종기;이화영;김성규;이재령;박재구
    • 한국토양환경학회지
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    • 제3권3호
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    • pp.21-31
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    • 1998
  • 폐광산 광미로부터 비소를 제거하기 위한 산침출 및 침전실험을 수행하였다. 다덕광산의 광미시료를 대상으로 염산 및 황산농도, 침출시간, 슬러리 농도에 따른 침출율의 변화를 조사함과 동시에 침출액 중의 비소성분을 침전시키기 위하여 pH조절과 Sodium Sulfide를 첨가하여 비소의 침전율을 관찰하였다. 염산침출의 경우 1시간 침출 후 산농도 및 슬러리 농도에 따라 40%에서 86%까지 비소침출율을 보였으며, 황산의 경우 47%∼77%의 침출율을 나타냈다. 침출시간에 따른 침출율의 변화는 10분이내에서 급격한 변화를 보이지만, 그후에는 침출시간이 증가함에 따라 완만한 증가를 보였다. 침출액중의 산농도가 높아지면 침출율이 증가하나 2N이상에서는 그 차이가 크지 않았다. 침출액을 반복사용할 경우 5회까지 꾸준히 침출이 일어나지만 그 증가폭은 점차 감소하였으며, 산농도가 높을수록 감소하는 추세가 보다 완만한 경향을 보였다. 침출액 중의 비소성분은 단순한 pH조절을 통하여 약 84%까지의 침전율을 보였으며, 침전제로 Sodium Sulfide 를 사용하였을 경우 99%이상의 침전율을 나타냈다.

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Glass Dissolution Rates From MCC-1 and Flow-Through Tests

  • Jeong, Seung-Young
    • 한국방사성폐기물학회:학술대회논문집
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    • 한국방사성폐기물학회 2004년도 학술논문집
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    • pp.257-258
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    • 2004
  • The dose from radionuclides released from high-level radioactive waste (HLW) glasses as they corrode must be taken into account when assessing the performance of a disposal system. In the performance assessment (PA) calculations conducted for the proposed Yucca Mountain, Nevada, disposal system, the release of radionuclides is conservatively assumed to occur at the same rate the glass matrix dissolves. A simple model was developed to calculate the glass dissolution rate of HLW glasses in these PA calculations [1]. For the PA calculations that were conducted for Site Recommendation, it was necessary to identify ranges of parameter values that bounded the dissolution rates of the wide range of HLW glass compositions that will be disposed. The values and ranges of the model parameters for the pH and temperature dependencies were extracted from the results of SPFT, static leach tests, and Soxhlet tests available in the literature. Static leach tests were conducted with a range of glass compositions to measure values for the glass composition parameter. The glass dissolution rate depends on temperature, pH, and the compositions of the glass and solution, The dissolution rate is calculated using Eq. 1: $rate{\;}={\;}k_{o}10^{(ph){\eta})}{\cdot}e^{(-Ea/RT)}{\cdot}(1-Q/K){\;}+{\;}k_{long}$ where $k_{0},\;{\eta}$ and Eaare the parameters for glass composition, pH, $\eta$ and temperature dependence, respectively, and R is the gas constant. The term (1-Q/K) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_{0},\;{\eta}\;and\;E_{a}$ are the parameters for glass composition, pH, and temperature dependence, respectively, and R is the gas constant. The term (1-Q/C) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_0$, and Ea are determined under test conditions where the value of Q is maintained near zero, so that the value of the affinity term remains near 1. The dissolution rate under conditions in which the value of the affinity term is near 1 is referred to as the forward rate. This is the highest dissolution rate that can occur at a particular pH and temperature. The value of the parameter K is determined from experiments in which the value of the ion activity product approaches the value of K. This results in a decrease in the value of the affinity term and the dissolution rate. The highly dilute solutions required to measure the forward rate and extract values for $k_0$, $\eta$, and Ea can be maintained by conducting dynamic tests in which the test solution is removed from the reaction cell and replaced with fresh solution. In the single-pass flow-through (PFT) test method, this is done by continuously pumping the test solution through the reaction cell. Alternatively, static tests can be conducted with sufficient solution volume that the solution concentrations of dissolved glass components do not increase significantly during the test. Both the SPFT and static tests can ve conducted for a wide range of pH values and temperatures. Both static and SPFt tests have short-comings. the SPFT test requires analysis of several solutions (typically 6-10) at each of several flow rates to determine the glass dissolution rate at each pH and temperature. As will be shown, the rate measured in an SPFt test depends on the solution flow rate. The solutions in static tests will eventually become concentrated enough to affect the dissolution rate. In both the SPFt and static test methods. a compromise is required between the need to minimize the effects of dissolved components on the dissolution rate and the need to attain solution concentrations that are high enough to analyze. In the paper, we compare the results of static leach tests and SPFT tests conducted with simple 5-component glass to confirm the equivalence of SPFT tests and static tests conducted with pH buffer solutions. Tests were conducted over the range pH values that are most relevant for waste glass disssolution in a disposal system. The glass and temperature used in the tests were selected to allow direct comparison with SPFT tests conducted previously. The ability to measure parameter values with more than one test method and an understanding of how the rate measured in each test is affected by various test parameters provides added confidence to the measured values. The dissolution rate of a simple 5-component glass was measured at pH values of 6.2, 8.3, and 9.6 and $70^{\circ}C$ using static tests and single-pass flow-through (SPFT) tests. Similar rates were measured with the two methods. However, the measured rates are about 10X higher than the rates measured previously for a glass having the same composition using an SPFT test method. Differences are attributed to effects of the solution flow rate on the glass dissolution reate and how the specific surface area of crushed glass is estimated. This comparison indicates the need to standardize the SPFT test procedure.

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A Comparative Analysis on Performance of Wireless Sensor Networks Routing Protocols

  • KRISHNA, KONDA. HARI;NAGPAL, TAPSI;BABU, Y. SURESH
    • International Journal of Computer Science & Network Security
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    • 제22권7호
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    • pp.240-244
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    • 2022
  • The common goals of designing a routing algorithm are not only to reduce control packet overhead, maximize throughput and minimize the end-to-end delay, but also take into consideration the energy consumption. Scalability is an important factor in designing an efficient routing protocol for wireless sensor networks (WSN's). Three metrics (power consumption, time of transmission and packet loss rate) are used in order to compare three routing protocols which are AODV, DSDV and LEACH.

Recycling of end-of-life LiNixCoyMnzO2 batteries for rare metals recovery

  • Sattar, Rabia;Ilyas, Sadia;Kousar, Sidra;Khalid, Amaila;Sajid, Munazzah;Bukhari, Sania Iqbal
    • Environmental Engineering Research
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    • 제25권1호
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    • pp.88-95
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    • 2020
  • An investigation of rare metals recovery from LiNixCoyMnzO2 cathode material of the end-of-life lithium-ion batteries is presented. To determine the influence of reductant on the leach process, the cathode material (containing Li 7.6%, Co 20.4%, Mn 19.4%, and Ni 19.3%) was leached in H2SO4 solutions either with or without H2O2. The optimal process parameters with respect to acid concentration, addition dosage of H2O2, temperature, and the leaching time were found to be 2.0 M H2SO4, 4 vol.% H2O2, 70℃, and 150 min, respectively. The yield of metal values in the leach liquor was > 99%. The leach liquor was subsequently treated by precipitation techniques to recover nickel as Ni(C4H7N2O2)2 and lithium as Li2CO3 with stoichiometric ratios of 2:1 and 1.2:1 of dimethylglyoxime:Ni and Na2CO3:Li, respectively. Cobalt was recovered by solvent extraction following a 3-stage process using Na-Cyanex 272 at pHeq ~5.0 with an organic-to-aqueous phase ratio (O/A) of 2/3. The loaded organic phase was stripped with 2.0 M H2SO4 at an O/A ratio of 8/1 to yield a solution of 114 g/L CoSO4; finally recovered CoSO4.xH2O by crystallization. The process economics were analyzed and found to be viable with a margin of $476 per ton of the cathode material.