• Title/Summary/Keyword: 금속 이온

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Recovery of Metallic Pd with High Purity from Pd/Al2O3 Catalyst by Hydrometallurgy in HCl (염산 침출용액을 이용한 Pd/Al2O3 촉매에서 고순도 팔라듐 회수)

  • Kim, Ye Eun;Byun, Mi Yeon;Baek, Jae Ho;Lee, Kwan-Young;Lee, Man Sig
    • Clean Technology
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    • v.26 no.4
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    • pp.270-278
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    • 2020
  • Palladium (Pd) has been widely used in various industrial applications such as jewelry, catalyst, and dental materials despite its limited resources. It has been gaining attention to recover Pd with high purity from the spent materials. This study investigated the optimum conditions for the leaching and recovery of metallic Pd. The leaching parameters are HCl concentration, temperature, time, concentration of oxidants, and pulp density. 97.2% of Pd leaching efficiency was obtained in 3 M HCl with 3 vol% oxidants at 80℃ for 60 min. The ratio of hydrogen peroxide to sodium hypochlorite played a critical role in the leaching efficiency due to the supply of Cl- ions in the leachate. Moreover, the complete recovery of Pd in the leachate was achieved at 80℃ with 0.3 formic acid/leachate after adjusting the pH value of 7. This situation was ascribed to the decomposition of formic acid into hydrogen gas and carbon dioxide at 80℃. ICP-AES and XRD characterized the recovered Pd powder, and the purity of the recovered powder was found to be 99.6%. Consequently, the recovered Pd powder with high purity could be used in circuits, catalyst precursors, and surgical instruments.

Behavior of Oxidative Precipitation of High-Arsenic (III) Solution Utilizing Activated Carbon with Air Injection (공기와 활성탄 병용에 의한 용액 중 고농도 3가 비소의 산화-침전 거동 연구)

  • Kim, Rina;Kim, Gahee;Kim, Kwanho;You, Kwang-suk
    • Resources Recycling
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    • v.30 no.4
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    • pp.11-19
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    • 2021
  • Arsenic (As) oxidation followed by precipitation from a high-As(III)-containing leaching solution derived from a sulfidic ore was investigated in this study to remove aqueous As from the solution using activated carbon (AC) with air injection as an oxidant. To obtain the initial leaching solution, a domestic sulfidic ore was leached in a sulfuric acid solution at pH 1 and 50℃ for 95 h, and approximately 7 g/L of Fe and 3 g/L of As were leached out. To determine the effect of the oxidative reaction utilizing AC with air injection, the leaching solution was tested under the following five oxidative conditions at an initial pH of 1 and 90℃ for 72 h: air-only injection; air injection with 1, 5, and 10 w/v% of AC addition; and H2O2 addition. The tests in the presence of both air and AC revealed that the oxidation kinetics and As removal were improved by the reaction between the metallic species and the surface group formed on the AC surface. In addition, the greater the amount of AC added, the better was the reaction efficiency, removing 93-94% of As with more than 5 w/v% of AC addition. Finally, X-ray diffraction analysis confirmed that the precipitate formed from the oxidative reaction was scorodite (FeAsO4·2H2O).

Electrochemical Performance of Rechargeable Lithium Battery Using Hybrid Solid Electrolyte (복합고체 전해질을 적용한 리튬이차전지의 전기화학적 특성)

  • Han, Jong Su;Yu, Hakgyoon;Kim, Jae-Kwang
    • Journal of the Korean Electrochemical Society
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    • v.24 no.4
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    • pp.100-105
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    • 2021
  • Recently, all-solid-state batteries have attracted much attention to improve safety of rechargeable lithium batteries, but the solid-state batteries of conductive ceramics or solid polymer electrolytes show poor electrochemical properties because of several problems such as high interfacial resistance and undesired reactions. To solve the problems of the reported all-solid-state batteries, a hybrid solid electrolyte is suggested, in this study, NASICON-type nanoparticle Li1.5Al0.5Ti1.5P3O12 (LATP) conductive ceramic, PVdF-HFP, and a carbonate-based liquid electrolyte were composited to prepare a quasi-solid electrolyte. The hybrid solid electrolyte has a high voltage stability of 5.6 V and shows an suppress effect of lithium dendrite growth in the stripping-plating test. The LiNi0.83Co0.11Mn0.06O2 (NCM811)-based battery with the hybrid solid electrolyte exhibits a high discharge capacity of 241.5 mAh/g at a high charge-cut-off voltage of 4.8V and stable electrochemical reaction. The NCM811-based battery also shows 139.4 mAh/g discharge capacity without short circuit or explosion at 90℃. Therefore, the LATP-based hybrid solid electrolyte can be an effective solution to improve the safety and electrochemical properties of rechargeable lithium batteries.

A Basic Study for Removal of Heavy Metal Elements from Wastewater using Spent Lithium-Aluminum-Silicate(LAS) Glass Ceramics (사용 후 유리세라믹(Lithium-Aluminum-Silicate)을 활용한 중금속 제거 기초 연구)

  • Go, Min-Seok;Wang, Jei-Pil
    • Resources Recycling
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    • v.31 no.4
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    • pp.49-55
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    • 2022
  • In this study, the heavy metal ions (of Pb, Cd, Cr, and Hg) in wastewater were removed using a spent Li2O-Al2O3-SiO2-based crystallized glass previously used as an induction top plate material. Changes in the removal efficiency of heavy metals according to different reaction parameters, such as the amount of zeolite used as a heavy-metal adsorbent, adsorption time, initial concentration of the heavy metals, and pH of the initial solution, were investigated. As the amount of zeolite added increased, the heavy-metal removal efficiency also increased. Adsorption time had a considerable influence on adsorption characteristics, and the removal efficiency of all heavy metals increased with increasing adsorption time. In the case of Cd, the removal efficiency was greatly improved depending on the adsorption time. The initial concentration of the heavy-metal solution did not affect the removal efficiency; however, the initial pH of the heavy-metal solution affected the removal efficiency. More specifically, the removal efficiency of Cd increased while that of Pb and Cr decreased with increasing pH. The adsorption characteristics of Hg were not significantly affected by pH.

Comparison of sample storage containers for the analysis of volatile organic compounds (VOC) (휘발성유기물(VOC) 분석을 위한 시료보관 용기의 비교)

  • Kim, Seokyung;Kim, Dalho
    • Analytical Science and Technology
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    • v.35 no.3
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    • pp.116-123
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    • 2022
  • Polymer bags, metallic canisters, and glass bottles have been used as containers for analyzing the volatile organic compounds (VOCs) in air. In this study, various sampling containers were compared to investigate the short-term stability of VOCs, that is, from the time they are sampled to the time they are analyzed. Polyvinyl fluoride (PVF), polypropylene (PP), polyester aluminum (PE-Al) bags, canisters, and glass bottles were used as sample containers. A 100 nmol/mol standard gas mixture of benzene, toluene, ethylbenzene, m-xylene, styrene, and o-xylene was used for the VOC comparison. Changes in the concentrations of samples stored for 10~20 day in each container were measured using a thermal desorption-gas chromatograph-flame ionization detector (TD-GC-FID). As a result, VOCs stored in a canister and two kinds of amber glass bottles have shown immaterial decreases in concentration in one week, and more than 80 % of the initial concentration was maintained for two weeks. In the case of polymer bags, the concentration of all VOCs, except benzene and toluene, were remarkably decreased below 70% of the initial concentration in one day. Particularly, ethylbenzene, xylene, and styrene have shown dramatic decreases in concentration below 30 % of the initial concentration in all polymer bags in one day.

Recovery of Silver from Nitrate Leaching Solution of Silicon Solar Cells (실리콘 태양전지 질산침출액에서 LIX63를 이용한 은(Ag) 회수)

  • Cho, Sung-Yong;Kim, Tae-Young;Sun, Pan-Pan
    • Resources Recycling
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    • v.30 no.2
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    • pp.39-45
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    • 2021
  • Spent photovoltaic module is one of the important resource of silver, while related research concerning silver recovery remains limited. In our previous research, HNO3 was utilized to dissolve Ag(I) and Al(III) from the spent silicon solar cells. In order to recover Ag(I) from the leachate of a silicon solar cell, the present study made use of a nitrate solution containing Ag(I) and Al(III), which was subjected to a solvent extraction process with 5,8-diethyl-7-hydroxydodecan-6-oxime (LIX63). Ag(I) was selectively extracted with LIX63 over Al(III) from the nitrate leach solution. Subsequently, quantitative stripping of Ag(I) from the loaded LIX63 was performed by using 20% ammonia water. The McCabe-Thiele plots for the extraction and stripping isotherms of Ag(I) were also constructed. Extraction and stripping simulation tests confirmed an Ag(I) extraction and stripping efficiency of >99.99% and 98.9%, respectively with high purity Ag (99.998%) and Al (99.99%) solution. A process flow sheet for Ag(I) recovery from the nitrate leach solution was proposed.

Analysis of Crushing/Classification Process for Recovery of Black Mass from Li-ion Battery and Mathematical Modeling of Mixed Materials (폐배터리 블랙 매스(black mass) 회수를 위한 파쇄/분급 공정 분석 및 2종 혼합물의 수학적 분쇄 모델링)

  • Kwanho Kim;Hoon Lee
    • Resources Recycling
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    • v.31 no.6
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    • pp.81-91
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    • 2022
  • The use of lithium-ion batteries increases significantly with the rapid spread of electronic devices and electric vehicle and thereby an increase in the amount of waste batteries is expected in the near future. Therefore, studies are continuously being conducted to recover various resources of cathode active material (Ni, Co, Mn, Li) from waste battery. In order to recover the cathode active material, black mass is generally recovered from waste battery. The general process of recovering black mass is a waste battery collection - discharge - dismantling - crushing - classification process. This study focus on the crushing/classification process among the processes. Specifically, the particle size distribution of various samples at each crushing/classification step were evaluated, and the particle shape of each particle fraction was analyzed with a microscope and SEM (Scanning Electron Microscopy)-EDS(Energy Dispersive Spectrometer). As a result, among the black mass particle, fine particle less than 74 ㎛ was the mixture of cathode and anode active material which are properly liberated from the current metals. However, coarse particle larger than 100 ㎛ was present in a form in which the current metal and active material were combined. In addition, this study developed a PBM(Population Balance Model) system that can simulate two-species mixture sample with two different crushing properties. Using developed model, the breakage parameters of two species was derived and predictive performance of breakage distribution was verified.

Estimate of Manganese and Iron Oxide Reduction Rates in Slope and Basin Sediments of Ulleung Basin, East Sea (동해 울릉분지 퇴적물에서 망간산화물과 철산화물 환원율 추정)

  • Choi, Yu-Jeong;Kim, Dong-Seon;Lee, Tae-Hee;Lee, Chang-Bok
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.14 no.3
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    • pp.127-133
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    • 2009
  • In order to determine organic carbon oxidation by manganese and iron oxides, six core sediments were obtained in slope and basin sediments of Ulleung Basin in East Sea. The basin sediments show high organic carbon contents (>2%) at the water depths deeper than 2,000 m; this is rare for deep-sea sediments, except for those of the Black Sea and Chilean upwelling regions. In the Ullleung Basin, the surface sediments were extremely enriched by Manganese oxides with more than 2%. Maximum contents of Fe oxides were found at the depth of $1{\sim}4cm$ in basin sediments. However, the high level of Mn and Fe oxides was not observed in slope sediment. Surface manganese enrichments (>2%) in Ulleung Basin may be explained by two possible mechanisms: high organic carbon contents and optimum sedimentation rates and sufficient supply of dissolved Manganese from slope to the deep basin. Reduction rates of iron and manganese oxides ranged from 0.10 to $0.24\;mmol\;m^{-2}day^{-1}$ and from 0.30 to $0.57\;mmol\;m^{-2}day^{-1}$, respectively. In Ulleung Basin sediments, $13{\sim}26%$ of organic carbon oxidation may be linked to the reduction of iron and manganese oxides. Reduction rates of metal oxides were comparable to those of Chilean upwelling regions, and lower than those of Danish coastal sediments.

A Study on the Prior Leaching and Recovery of Lithium from the Spent LiFePO4 Cathode Powder Using Strong Organic Acid (강유기산을 이용한 폐LiFePO4 양극분말로부터 리튬의 선침출에 대한 연구)

  • Dae-Weon Kim;Soo-Hyun Ban;Hee-Seon Kim;Jun-Mo Ahn
    • Clean Technology
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    • v.30 no.2
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    • pp.105-112
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    • 2024
  • Globally, the demand for electric vehicles has surged due to greenhouse gas regulations related to climate change, leading to an increase in the production of used batteries as a consequence of the battery life issue. This study aims to selectively leach and recover valuable metal lithium from the cathode material of spent LFP (LiFePO4) batteries among lithium-ion batteries. Generally, the use of inorganic acids results in the emission of toxic gases or the generation of large quantities of wastewater, causing environmental issues. To address this, research is being conducted to leach lithium using organic acids and other leaching agents. In this study, selective leaching was performed using the organic acid methane sulfonic acid (MSA, CH3SO3H). Experiments were conducted to determine the optimal conditions for selectively leaching lithium by varying the MSA concentration, pulp density, and hydrogen peroxide dosage. The results of this study showed that lithium was leached at approximately 100%, while iron and phosphorus components were leached at about 1%, verifying the leaching efficiency and the leaching rates of the main components under different variables.

Study of Conversion of Waste LFP Battery into Soluble Lithium through Heat Treatment and Mechanochemical Treatment (열처리 및 기계화학적 처리를 통한 폐LFP 배터리로부터 가용성 리튬으로의 전환 연구)

  • Boram Kim;Hee-Seon Kim;Dae-Weon Kim
    • Resources Recycling
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    • v.33 no.3
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    • pp.21-29
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    • 2024
  • Globally, the demand for electric vehicles (EVs) is surging due to carbon-neutral strategies aimed at decarbonization. Consequently, the demand for lithium-ion batteries, which are essential components of EVs, is also rising, leading to an increase in the generation of spent batteries. This has prompted research into the recycling of spent batteries to recover valuable metals. In this study, we aimed to selectively leach and recover lithium from the cathode material of spent LFP batteries. To enhance the reaction surface area and reactivity, the binder in the cathode material powder was removed, and the material was subjected to heat treatment in both atmospheric and nitrogen environments across various temperature ranges. This was followed by a mechanochemical process for aqueous leaching. Initially, after heat treatment, the powder was converted into a soluble lithium compound using sodium persulfate (Na2S2O8) in a mechanochemical reaction. Subsequently, aqueous leaching was performed using distilled water. This study confirmed the changes in the characteristics of the cathode material powder due to heat treatment. The final heat treatment in a nitrogen atmosphere resulted in a lithium leaching efficiency of approximately 100% across all temperature ranges.