• Title, Summary, Keyword: valuable metals

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Recovery of Valuable Metal from e-Wasted Electronic Devices (폐전자부품에서 유가금속 회수기술)

  • Kim, Yu-Sang
    • Journal of the Korean institute of surface engineering
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    • v.49 no.6
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    • pp.477-485
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    • 2016
  • As expensive and valuable metals being used in electronic and semiconducting industries are abandoned as industrial wastes after use of them, it is required to recover them from e-wasted electronics parts. Gold which is used for printed circuit boards or electronic equipments, accessories, etc., is one of e-Wasted materials and recently indium, gallium, zirconium, cobalt, molybdenum and lithium are bacome valuable metals to be recovered from the e-wastes. Since the amount of precious metals is now being faced with scarcity, lean too much on area and instability of supply, and industrial demands are rapidly increasing every year, it becomes more important to recover the valuable metals from the industrial wastes. In this review, we introduced technologies and research trend of the recovery processes of valuable metals from the e-wastes in high-tech devices over the world.

A Study on Improvement of Valuable Metals Leaching and Distribution Characteristics on Waste PCBs(Printed Circuit Boards) by Using Pulverization Process (폐 PCBs의 미분쇄 공정 적용에 따른 유가금속 분포 특성 및 금속 침출 향상에 관한 연구)

  • Han, Young-Rip;Choi, Young-Ik
    • Journal of Environmental Science International
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    • v.24 no.2
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    • pp.245-251
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    • 2015
  • The main objective of this study is to recovery valuable metals with metal particle size distributions in waste cell phone PCBs(Printed Circuit Boards) by means of pulverization and nitric acid process. The particle size classifier also was evaluated by specific metal contents. The PCBs were pulverized by a fine pulverizer. The particle sizes were classified by 5 different sizes which were PcS1(0.2 mm below), PcS2(0.20~0.51 mm), PcS3(0.51~1.09 mm), PcS4(1.09~2.00 mm) and PcS5(2.00 mm above). Non-magnetic metals in the grinding particles were separated by a hand magnetic. And then, Cu, Co and Ni were separated by 3M nitric acid. Particle diameter of PCBs were 0.388~0.402 mm after the fine pulverizer. The sorting coefficient were 0.403~0.481. The highest metal content in PcS1. And the bigger particle diameter, the lower the valuable metals exist. The recovery rate of the valuable metals increases in smaller particle diameter with same leaching conditions. For further work, it could improve to recovery of the valuable metals effectively by means of individual treatment, multistage leaching and different leaching solvents.

Review on Evaluation of Rare Earth Metals and Rare Valuable Metals Contained in Coal Ash of Coal-fired Power Plants in Korea

  • Park, Seok-Un;Kim, Jae-Kwan;Seo, Yeon-Seok;Hong, Jun-Seok;Lee, Hyoung-Beom;Lee, Hyun-Dong
    • KEPCO Journal on Electric Power and Energy
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    • v.1 no.1
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    • pp.121-125
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    • 2015
  • Distribution of rare earth metals (REMs) and rare valuable metals (RVMs) contents in coal ashes (fly ash, bottom ash, and pond ash) and leachate from 11 coal-fired power plants in Korea were investigated. Coal ashes and leachates were found to contain important REMs and RVMs such as Yttrium (Y) and Neodymium (Nd), which was in the range of 23~75 mg/kg. However, it still requires developing effective recovery and separation methods in order to utilize REMs and RVMs in ash and leachate. Recovery of valuable elements (Y and Nd) from various and extensive ash sources (8.21 million tons/year in 2013) can provide the existing power plants with additional profit; therefore, it can significantly improve economics of the power plants.

Preliminary Status Analysis Methodology on Hazardous and Valuable Metal Recovery in Industrial Wastes Using Public Database (공공 자료를 활용한 산업폐기물내 유해성 유가금속 회수관련 초기 현황조사 방안)

  • Lee, Sang-hun
    • Resources Recycling
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    • v.29 no.2
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    • pp.48-54
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    • 2020
  • Korea, one of the manufacturing-oriented countries, consumes a large amount of metals in various industrial areas, but should depend on import of most of the metals from foreign countries. Also, global metal consumption amounts are increasing in relation to those of the world's reserve and production. Some metals are limitedly produced from only several centuries, which might lead to instability of the future supply of those metals. In addition, when such metals are hazardous, those may result in various environmental troubles with contamination. To resolve those issues, the recovery and the recycling of hazardous but valuable metals in industrial waste are desirable. However, there are overwhelming numbers of the metal types, waste generators, and amounts of wastes containing the metals, so it can be troublesome even to implement a preliminary status analysis to screen proper metals, wastes with the metals, and waste producers. Therefore, this study introduces the valuable metals for Korean industry, announced by public institutions, Also, a flow chart is suggested to facilitate a preliminary status analysis, using the domestic PRTR (Pollutant Release and Transfer Register) database, to screen proper waste producers containing some of hazardous but valuable metals such as nickel, cobalt, and manganese.

The Effect of Milling Conditions for Dissolution Efficiency of Valuable Metals from PDP Waste Panels (밀링조건이 사용 후 PDP패널의 유가금속 용출효율에 미치는 영향)

  • Kim, Hyo-Seob;Kim, Chan-Mi;Lee, Chul-Hee;Lee, Sung-Kyu;Hong, Hyun-Seon;Koo, Jar-Myung;Hong, Soon-Jik
    • Journal of Korean Powder Metallurgy Institute
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    • v.20 no.2
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    • pp.107-113
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    • 2013
  • In this study, the microstructure and valuable metals dissolution properties of PDP waste panel powders were investigated as a function of milling parameters such as ball diameter size, milling time, and rotational speed during high-energy milling process. The complete refinement of powder could achieved at the ball diameter size of 5 mm due to sufficient impact energy and the number of collisions. With increasing milling time, the average particle size was rapidly decreased until the first 30 seconds, then decreased gradually about $3{\mu}m$ at 3 minutes and finally, increased with presence of agglomerated particles of $35{\mu}m$ at 5 minutes. Although there was no significant difference on the size of the particle according to the rotational speed from 900 to 1,100 rpm, the total valuable metals dissolution amount was most excellent at 1,100 rpm. As a result, the best milling conditions for maximum dissolving amount of valuable metals (Mg: 375 ppm, Ag 135 ppm, In: 17 ppm) in this research were achieved with 5 mm of ball diameter size, 3min of milling time, and 1,100 rpm of rotational speed.

Present State and Prospect on Reutilization of Metal - Bearing Solid Wastes in China

  • Chai, Liyuan;Chen, Weiliang;Min, Xiaobo;He, Dewen;Zhang, Chuanfu
    • Proceedings of the IEEK Conference
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    • pp.183-187
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    • 2001
  • Present states on reutilization of metal-bearing solid wastes in China including metal-containing gangue, red mud, nonferrous metallurgical slag or residue, arsenical slag, steel - iron slag, waste batteries, were described in detail. The wastes pile up at a large quantity, resulting in seriously potential harm to environment. Most of these wastes, however, contain valuable metals, which are regarded as important secondary resources for extracting metals. Waste slag and batteries with a high grade of metals are treated by a hydro-based and / or pyre-based method for extracting valuable metals. While gangue and waste slag with a low grade are as a raw material in architecture field. In the future, a novel technology, such as high-grads magnetization separation technique and biological technique, will be designed to treat these wastes for protecting environment and recycling valuable components. These wastes, furthermore, are synthetically reutilized to produce various architectural materials, including glass and ceramics.

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Current Status on the Pyrometallurgical Process for Recovering Precious and Valuable Metals from Waste Electrical and Electronic Equipment(WEEE) Scrap (폐전기전자기기(廢電氣電子機器) 스크랩으로부터 귀금속(貴金屬) 및 유가금속(有價金屬) 회수(回收)를 위한 건식공정(乾式工程) 기술(技術) 현황(現況))

  • Kim, Byung-Su;Lee, Jae-Chun;Jeong, Jin-Ki
    • Resources Recycling
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    • v.18 no.4
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    • pp.14-23
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    • 2009
  • In terms of resources recycling and resolving waste disposal problems, it is very important to recover precious metals like Au, Ag and Pd and valuable metals like Cu, Sn and Ni from the scraps of waste electrical and electronic equipment(WEEE) that consists of detective electrical and electronic parts discarded during manufacturing electrical and electronic equipments and waste electrical and electronic parts generated during disassembling them. In general, the scraps of WEEE are composed of various metals and alloys as well as refractory oxides and plastic components. Precious and valuable metals from the scraps of WEEE can be recovered by gas-phase-volatilization, hydrometallurgical, or pyrometallurgical processes. However, the gas-phase-volatilization and hydrometallurgical processes have been suggested but not yet commercialized. At the present time, most of the commercial plants for recovering precious and valuable metals from the scraps of WEEE adopt pyrometallurgical processes. Therefore, in this paper, the technical and environmental aspects on the important pyrometallurgical processes through literature survey are reviewed, and the scale-up result of a new pyrometallurgical process for recovering the precious and valuable metals contained in the scraps of WEEE using waste copper slag is presented.

Sulfuric Acid Leaching of Valuable Metals from Spent Petrochemical Catalyst using Hydrogen Peroxide as a Reducing Agent

  • Park, Kyung-Ho;Sohn, Jeong-Soo;Kim, Jong-Seok
    • Proceedings of the IEEK Conference
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    • pp.478-481
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    • 2001
  • The spent petrochemical catalyst used in the manufacturing process of terephthalic-acid contains valuable metals such as cobalt and manganese. To recover these metals, sulfuric acid leaching was performed with hydrogen peroxide as a reducing agent. Low extractions of Mn, Co and Fe were obtained by sulfuric acid leaching without reducing agent. With adding hydrogen peroxide as a reducing agent, the high extraction of these metals could be obtained. Different from general leaching experiment, the extraction rates of metal components were decreased with increasing reaction temperature in this case. Under the optimum condition, the extraction rates of Mn, Co and Fe were 93.0%, 87.0% and 100% respectively.

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Selective leaching of valuable metals (Au, Ag etc.) from waste printed circuit boards (PCB)

  • Oh, Chi-Jung;Lee, Sung-Oh;Song, Jin-Kon;Kook, Nam-Pyo;Kim, Myong-Jun
    • Proceedings of the IEEK Conference
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    • pp.193-197
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    • 2001
  • This study was carried out to recover gold, silver and other valuable metals from the printed circuit boards (PCB) of waste computers. PCB samples were crushed to under 1mm by a shredder and initially separated into 30% conducting and 70% non-conducting materials by an electrostatic separator. The conducting materials, which contained the valuable metals, were then used as the feed material for magnetic separation where it was found that 42% was magnetic and 58% non- magnetic. The non-magnetic materials contained 0.227mg/g Au and 0.697mg/g Ag. Further leaching of the non-magnetic component using 2.0M sulfuric acid and 0.2M hydrogen peroxide at 85$^{\circ}C$ extracted more than 95% copper, iron, zinc, nickel and aluminium. Au and Ag were not extracted in this solution, however, more than 95% of Au and 100% of Ag were selectively leached with a mixed solvent (0.2M ammonium thiosulfate, 0.02M copper sulfate, 0.4M ammonium hydroxide). Finally, the residues were reacted with a NaCl solution to leach out Pb while sulfuric acid was used to leach out Sn. Recoveries reached 95% and 98% in solution, respectively.

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