• Title/Summary/Keyword: Li Recovery

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Hyphae and organic acids of Aspergillus Niger promote uranium recovery by destroying the ore surface and increasing the porosity and permeability of ores

  • Yongdong Wang;Jinhua Wang;Dexin Ding;Guangyue Li;Jing Sun;Nan Hu;Feng Li;Jianhong Ma;Hui Zhang;Yang Ding;Zhongran Dai
    • Nuclear Engineering and Technology
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    • v.56 no.5
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    • pp.1880-1886
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    • 2024
  • To elucidate the mechanism of damage caused by hyphae and organic acids produced by Aspergillus Niger on the surface and internal structure of uranium ore, direct uranium leaching, indirect uranium leaching and semidirect uranium leaching were conducted, and the surface morphology, strength, mineral crystallinity, porosity, and permeability of the ore were analyzed. The results demonstrated that the combination of biomechanical forces exerted by hyphae and the complexation effects of organic acids led to the dissolution of SiO2 and other substances on the surface of ore, resulting in exfoliation from the exterior to the interior, thereby promoting uranium recovery. Furthermore, the proton exchange involving H+ and the complexation of organic acids resulted in the dissolution of cations within the ore, causing destruction to the crystal lattice structure of minerals and increasing the porosity and permeability inside the ore. The dominant factor contributing to ore damage during recovery was organic acids.

Potentiometric CO2 gas sensor based on the thin film electrolyte of Li+ ion conductor (박막 리튬이온전도체를 이용한 전위차 CO2 가스센서)

  • Noh, Whyo-Sub;Choi, Gwang-Pyo;Song, Ho-Geun;Park, Jin-Seong
    • Journal of Sensor Science and Technology
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    • v.14 no.4
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    • pp.258-264
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    • 2005
  • Li+-ion conducting ($Li_{3}PO_{4}$) thin films with thickness of $0.3{\mu}m$, $0.65{\mu}$, $1.2{\mu}$ were deposited on $Al_{2}O_{3}$ substrate at room temperature by thermal evaporation. They were sintered at $700^{\circ}C$ and $800^{\circ}C$ for 2 hours, respectively. Reference electrode and sensing electrode were printed on Au-electrode by silk printing method. The EMF and the ${\Delta}EMF$/dec were increased with increasing the electrolyte thickness and sintering temperature. The sample sintered at $800^{\circ}C$ was shown a good response and recovery characteristics more than those sintered at $700^{\circ}C$. The Nernst's slop of 75 mV per decade was obtained at operating temperature of $500^{\circ}C$.

$\textrm{CO}_2$ Gas Sensor Based on $\textrm{Li}_2\textrm{ZrO}_3$ System ($\textrm{Li}_2\textrm{ZrO}_3$ 계를 이용한 $\textrm{CO}_2$ 가스 센서)

  • Park, Jin-Seong;Kim, Si-Uk;Lee, Eun-Gu;Kim, Jae-Yeol;Lee, Hyeon-Gyu
    • Korean Journal of Materials Research
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    • v.9 no.9
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    • pp.896-899
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    • 1999
  • A carbon dioxide gas sensor was studied as a function of temperature and $CO_2$concentration in the Li$_2$ZrO$_3$ system. Lithium zirconate(Li$_2$ZrO$_3$) was synthesized by the heat-treatment of zirconia(ZrO$_2$)and Lithium carbonate(Li$_2$CO$_3$). The specimens were prepared both as bulk disk, 10mm in diameter and 1.0mm thickness, and thick films on an alumina substrate. Lithium zirconate readily responded to $CO_2$concentration from 0.1% to 100% in the range of 45$0^{\circ}C$ to $650^{\circ}C$. The sensitivity to $CO_2$ was dependent on the measuring temperature. Lithium zirconate(Li$_2$ZrO$_3$) decomposes into Li$_2$CO$_3$ and ZrO$_2$after the reaction with $CO_2$in the range of 45$0^{\circ}C$ to $650^{\circ}C$. Li$_2$CO$_3$ changes into Li$_2$O and $CO_2$ above $650^{\circ}C$. The material showed difficulty with reversibility and recovery. The optimum temperature for the highest sensitivity is around 55$0^{\circ}C$.

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Synthesis of Needle-Like Aragonite Crystals in the Presence of Magnesium Chloride and Their Application in Papermaking

  • Hu, Zeshan;Shao, Minghao;Li, Huayang;Cai, Qiang;Zhong, Chenghua;Xianming, Zhang;Deng, Yulin
    • Advanced Composite Materials
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    • v.18 no.4
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    • pp.315-326
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    • 2009
  • PCC (precipitated calcium carbonate) and ground calcium carbonate have been widely used in alkaline papermaking. Unfortunately, although increasing filler level in papers can improve the paper properties such as brightness, opacity, stiffness gloss, smoothness, porosity, and printability, as well as decrease cost, some strength of the paper is negatively affected. In this research, needle-like aragonite was synthesized using $Ca(OH)_2$ and $CO_2$ as reactants in the presence of $MgCl_2$ and characterized with scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The physical and optical properties of the paper handsheets containing these needle-like aragonite fillers were evaluated. Results indicated that tensile strength, Z-direction tensile strength and folding endurance of the paper were improved by the needle-like aragonite crystals compared to the paper using commercial PCC (precipitated calcium carbonate) as filler. The stiffness of the paper handsheet on the machine direction was increased, but no evident difference in the cross direction was found. The improvement of paper strength mainly resulted from the twining effect between the aragonite whiskers and paper fibers. The optical properties of the paper were slightly decreased with the use of the needle-like aragonites compared to commercial PCC. These results suggest that paper cost can be decreased by increasing the content of needle-like aragonite filler while paper strength will not be decreased compared to PCC filler.

Recovery of mortar-aggregate interface of fire-damaged concrete after post-fire curing

  • Li, Lang;Zhang, Hong;Dong, Jiangfeng;Zhang, Hongen;Jia, Pu;Wang, Qingyuan;Liu, Yongjie
    • Computers and Concrete
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    • v.24 no.3
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    • pp.249-258
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    • 2019
  • In order to investigate the strength recovery of fire-damaged concrete after post-fire curing, concrete specimens were heating at $2^{\circ}C/min$ or $5^{\circ}C/min$ to 400, 600 and $800^{\circ}C$, and these exposed specimens were soaked in the water for 24 hours and following by 29-day post-fire curing. The compressive strength and split tensile strength of the high-temperature-exposed specimens before and after post-fire curing were tested. The proportion of split aggregate in the split surfaces was analyzed to evaluate the mortar-aggregate interfacial strength. After the post-fire curing process, the split tensile strength of specimens exposed to all temperatures was recovered significantly, while the recovery of compressive strength was only obvious within the specimens exposed to $600^{\circ}C$. The tensile strength is more sensitive to the mortar-aggregate interfacial cracks, which caused that the split tensile strength decreased more after high-temperature exposure and recovery more after post-fire curing than the compressive strength. The mortar-aggregate interfacial strength also showed remarkable recovery after post-fire curing, and it contributed to the recovery of split tensile strength.

A Study of Cadmium Recovery from LCC Crucible Using Solid-liquid Separation Method (고-액 분리법을 이용한 LCC 도가니에서의 카드뮴 회수에 관한 연구)

  • Park, Dae-Yeob;Kim, Tack-Jin;Kim, Jiyong;Kim, Kyung-Ryang;Kim, Si-Hyung;Shim, Joon-Bo;Peak, Seungwoo;Ahn, Do-Hee
    • Journal of Advanced Engineering and Technology
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    • v.4 no.4
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    • pp.431-436
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    • 2011
  • This study was carried out to reduce the problem during distillation process, which separate U, TRU (TRans Uranium) metal electro deposit, Cd and LiCl-KCl eutectic salt generating from LCC (Liquid Cadmium Cathode) electro winning process. The cadmium recovering apparatus was manufactured to separate for each metal using solid-liquid separation method. The apparatus consists of the first sieve for the separation of U and TRU metal electrodeposit, the second sieve for the separation of LiCl-KCl eutectic salt, cadmium collection basket, and a heating furnace. In addition, the size of each sieve is 2 mm to 3 mm. In this experiment, a metal wire was employed to replace TRU metal electrodeposit and U, which exist actually in a LCC crucible. In the solid state, The LiCl-KCl is separated at 340℃ at which the solid and the liquid of the remaining cadmium and LiCl-KCl eutectic salt coexists in each, after the metal wire separated at 500℃. As a result, it seems that it would be beneficial to set the processing condition in the distillation process with the additional treatment process of cadmium and LiCl-KCl eutectic salt.

Electrorefining Behavior of Zirconium Scrap with Multiple Cathode in Fluoride-Based Molten Salt (불화물계 용융염을 이용한 지르코늄 스크랩의 다중전극 전해정련 거동)

  • Park, Dong Jae;Kim, Seung Hyun;Park, Kyoung Tae;Mun, Jong Han;Lee, Hyuk Hee;Lee, Jong Hyeon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.13 no.1
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    • pp.11-19
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    • 2015
  • The production of nuclear fuel cladding tube is expected to increase with the nuclear power plant expansion. Zirconium(Zr) scrap that is generated during manufacturing is also expected to increase. Zr electrorefining experiment was carried out in the fluoride salt of LiF-KF-ZrF4 using multiple electrode for scale up and improving throughput Zr electrorefiner develop-ment. The Zr reduction peak observed at-0.8 V(vs.Ni). Polarization behavior showed that the amount of applied current increases because of decreasing cell resistance as the number of cathode increases. Experimental results showed the highest recovery rate about 98% at lowest current density of 25.64 mA/cm2 using 6 electrodes. XRD and TG analysis result show that pure Zr was recovered 99.92% and ICP analysis shows that lower impurity content than conventional impurity content of the Anode(97.8%). Electrorefining consumes energy about 7.15 kWh/kg less than 39.7% compared to the Kroll process using 6 electrode width of 20 mm and height of 65 mm. Because of increasing cell efficiency and recovery rate, using multiple cathode is determined as an efficient technique for scale up electrorefining Zr scrap.

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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    • v.25 no.1
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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.

A Study on the Leaching Effect and Selective Recovery of Lithium Element by Persulfate-based Oxidizing Agents from Waste LiFePO4 Cathode (과황산계 산화제에 따른 폐LiFePO4 양극재에서 리튬의 침출 효과와 선택적 회수에 대한 연구)

  • Kim, Hee-Seon;Kim, Dae-Weon;Jang, Dae-Hwan;Kim, Boram;Jin, Yun-Ho;Chae, Byung-Man;Lee, Sang-Woo
    • Resources Recycling
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    • v.31 no.4
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    • pp.40-48
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    • 2022
  • In waste lithium iron phosphate (LFP) batteries, the cathode material contains approximately 4% lithium. Recycling the constituent elements of batteries is important for resource circulation and for mitigating the environmental pollution. Li contained in the waste LFP cathode powder was selectively leached using persulfate-based oxidizing agents, such as sodium persulfate, potassium persulfate, and ammonium persulfate. Leaching efficiency and waste LFP powder properties were compared and analyzed. Pulp density was used as a variable during leaching, which was performed for 3 h under each condition. The leaching efficiency was calculated using the inductively coupled plasma (ICP) analysis of the leachate. All types of persulfate-based oxidizing agents used in this study showed a Li leaching efficiency over 92%. In particular, when leaching was performed using (NH4)2S2O8, the highest Li leaching percentage of 93.3% was observed, under the conditions of 50 g/L pulp density and an oxidizing agent concentration of 1.1 molar ratio.

The System of Waste Home Appliances Recycling in Taiwan

  • Ma, H.K.;Li, K.C.;Wu, N.M.;Chang, W.C.
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.43-47
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    • 2001
  • The waste home appliances including television sets, refrigerators, washing machines and air conditioners have increasingly received environmental concerns in Taiwan. In light of the enforcement of Waste Disposal Act (WDA), the Taiwan Environmental Protection Administration (EPA) has certified 60 recycling/storage facilities and given permission for qualified companies to build six treatment plants around the island. Now the recycling and well treatment home appliances are estimated to be 3,342,369 units until May 31, 2001. This paper describes the present status of waste home appliance recycle and its treatment in Taiwan. The principle guidelines and policies regarding recycling, resource recovery and environmental concerns are presented.

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