• Title, Summary, Keyword: hydrometallurgy

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Recovery of Tungsten from WC/Co Hardmetal Sludge by Alkaline Leaching Hydrometallurgy Process (WC/Co 초경합금 가공 슬러지로부터 알칼리침출 정련공정에 의한 W 회수)

  • Lee, Gil-Geun;Kwon, Ji-Eun
    • Journal of Korean Powder Metallurgy Institute
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    • v.23 no.5
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    • pp.372-378
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    • 2016
  • This study focuses on the development of an alkaline leaching hydrometallurgy process for the recovery of tungsten from WC/Co hardmetal sludge, and an examination of the effect of the process parameters on tungsten recovery. The alkaline leaching hydrometallurgy process has four stages, i.e., oxidation of the sludge, leaching of tungsten by NaOH, refinement of the leaching solution, and precipitation of tungsten. The WC/Co hardmetal sludge oxide consists of $WO_3$ and $CoWO_4$. The leaching of tungsten is most affected by the leaching temperature, followed by the NaOH concentration and the leaching time. About 99% of tungsten in the WC/Co hardmetal sludge is leached at temperatures above $90^{\circ}C$ and a NaOH concentration above 15%. For refinement of the leaching solution, pH control of the solution using HCl is more effective than the addition of $Na_2S{\cdot}9H_2O$. The tungsten is precipitated as high-purity $H_2WO_4{\cdot}H_2O$ by pH control using HCl. With decreasing pH of the solution, the tungsten recovery rate increases and then decrease. About 93% of tungsten in the WC/Co hardmetal sludge is recovered by the alkaline leaching hydrometallurgy process.

Lithium ion car batteries: Present analysis and future predictions

  • Arambarri, James;Hayden, James;Elkurdy, Mostafa;Meyers, Bryan;Abu Hamatteh, Ziad Salem;Abbassi, Bassim;Omar, Waid
    • Environmental Engineering Research
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    • v.24 no.4
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    • pp.699-710
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    • 2019
  • Electric vehicles (EVs) are spreading rapidly and many counties are promoting hybrid and fully EVs through legislation. Therefore, an increasing amount of lithium ion batteries will reach the end of their usable life and will require effective and sustainable end-of-life management plan which include landfill disposal or incineration. The current research focuses on more sustainable methods such as remanufacturing, reuse and recycling in order to prepare for future battery compositions and provide insights to the need recycling methods to be developed to handle large amounts of batteries sustainably in the near future. The two most prominent material recovery techniques are hydrometallurgy and pyrometallurgy which are explored and assessed on their relative effectiveness, sustainability, and feasibility. Hydrometallurgy is a superior recycling method due to high material recovery and purity, very low emissions, high prevalence of chemical reuse and implementation of environmentally sustainable compounds. Expanding recycling technologies globally should take the research and technologies pioneered by Umicore to establish a sustainable recycling program for end-of-life EVs batteries. Emerging battery technology of Telsa show the most effective designs for high performance batteries includes the use of silicon which is expected to increase capacity of batteries in the future.

A Study on Classification of Limonite and Saprolite from Nickel Laterite Ores (뉴칼레도니아산 니켈라테라이트광의 분급 연구)

  • Seo, Joobeom;Kim, Kee-seok;Bae, In-kook;Lee, Jae-young;Kim, Hyung-seok
    • Journal of the Korean Institute of Resources Recycling
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    • v.25 no.1
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    • pp.40-47
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    • 2016
  • Nickel laterite ore is classified into two principal ore types: saprolite (silicate ore) and limonite (oxide ore). Saprolite-type ore characterized by high magnesia and silica contents is treated by pyrometallurgy process. On the other hand, limonite-type ore is subjected to hydrometallurgy process to produce nickel products. Hydrometallurgy process requires that a raw material to meet the demands that Si+Mg contents lower than 10% and Fe content over than 40%. It is therefore required that separation of saprilite-type ore to use nickel laterite ore as a raw material for hydrometallurgy process. In this study, separation of sparolite-type ore and limonite-type ore from nickel laterite ore from New Caledonia has been tried by dry classification. The results show that -5 mm size fraction and +5 mm size fraction of the nickel laterite ore contains mainly limonite-type ore and saprolite-type ore, respectively. To understand the moisture content of the raw ore on the dry classification, nickel laterite ore with different moisture contents of 23.0% and 9.1% were subjected to the dry classification. The results show that drying of the ore makes the separation more efficient as the amount of the fine product, that can be subjected to hydrometallurgy process without further separation or drying operations, was increased.

Development of Ammoniacal Leaching Processes; A Review (암모니아 침출공정(浸出工程) 기술개발(技術開發) 동향(動向))

  • Yoo, Kyoungkeun;Kim, Hyunjung
    • Journal of the Korean Institute of Resources Recycling
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    • v.21 no.5
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    • pp.3-17
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    • 2012
  • Selective leaching processes for copper, gold, nickel, and cobalt have been investigated because there is an advantage of ammoniacal hydrometallurgy that metal such as copper could be selectively extracted restricting the dissolution of iron or calcium. In the present article, the studies for selective ammoniacal leaching of copper from motor scraps and waste printed circuit boards (PCBs), for ammoniacal leaching of gold to decrease the amount of cyanide used or to substitute cyanide by thiosulfate, and for ammoniacal leaching to recover nickel and cobalt from nickel oxide ore and intermidiate obtained from manganese nodule treatment process were summarized and further studies were proposed for domestic technology development for ammoniacal hydrometallurgy processes.

Microbial leaching

  • 이홍금
    • The Microorganisms and Industry
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    • v.16 no.3
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    • pp.40-43
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    • 1990
  • 미생물을 이용하여 광석더미에서 광물을 침출하고 금속을 선광하는 방법(microbial leaching)은 자원고갈현상에 대한 대비책으로 1950년 이후 각광을 받고 있다. Microbial leaching은 hydrometallurgy의 한 분야로 저렴한 비용및 간단한 기술로도 순도가 낮은 광석에서 금속을 여과해낼 수 있고 또 recycling system이라 환경을 오염시키지 않는다는 등의 많은 장점을 지니고 있다. 현재에는 생물공학의 발달과 함께 금속선광에 중요한 미생물의 유전자를 전이시켜 다양한 광석및 금속에 대한 선광능력을 증가시킬 수도 있다. 본 고에서는 선광에 적합한 미생물의 생태, 생리학적 특이성과 leaching에 있어서의 생물공학의 상업적 중요성에 대해 간단히 논의하고자 한다.

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Analysis of Oxidation-reduction Equilibria in Aqueous Solution Through Frost Diagram (Frost도를 이용한 수용액의 산화-환원반응 평형 해석)

  • Lee, Man Seung
    • Journal of the Korean Institute of Resources Recycling
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    • v.26 no.4
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    • pp.3-8
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    • 2017
  • Oxidation-reduction reaction is one of the most important reactions occurring in the aqueous phase. Analysis of the equilibria related to these oxidation-reduction reactions is of great value in designing many unit operations in hydrometallurgy, such as leaching, separation and electrochemical reactions. The construction of Frost diagram was discussed in this work. The conditions at which disproportionation and proportionation reactions can occur were explained by analyzing Frost diagram together with Latimer table. The information which can be obtained from Frost diagram was discussed.

Hydrometallurgical Processes for the Recovery of Tungsten from Ores and Secondary Resources (원광석 및 2차 자원으로부터 텅스텐 습식 제련 기술)

  • Ahn, Hyeong Hun;Lee, Man Seung
    • Journal of the Korean Institute of Resources Recycling
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    • v.27 no.6
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    • pp.3-10
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    • 2018
  • Tungsten is a metal with high melting point and used as a raw material for the production of super alloys. Tungsten exists as $WO{_4}^{2-}$ in alkaline solution. As solution pH decreases, polymerization reaction of $WO{_4}^{2-}$ occurs to result in the precipitation of tungstic acid. The hydrometallurgical process for the recovery of tungsten from ores or secondary resources can be classified as acid and alkaline leaching. In selecting a process for the recovery of pure tungsten from secondary resources, the nature and concentration of impurities in the secondary resources and the manufactured tungsten materials should be considered.

Aqueous Chemistry of Boric Acid (보론산의 용액 화학)

  • Lee, Man Seung
    • Journal of the Korean Institute of Resources Recycling
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    • v.27 no.4
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    • pp.23-28
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    • 2018
  • Distribution data of boric acid in water is necessary to develop a hydrometallurgical process for the recovery of boron from primary and secondary resources containing boron. Boric acid exists as $B(OH)_3$ and $B(OH)_4{^-}$ when solution pH is less than 6 and higher than 12, respectively. In the solution pH range of 6-11, condensation reaction between $B(OH)_3$ and $B(OH)_4{^-}$ results in the formation of some polymers. The mole fraction of the boron polymers such as $B_3O_3(OH)_4{^-}$ and $B_4O_5(OH){_4}^{2-}$ is proportional to the concentration of boric acid.

Chemical Leaching of Silver from Diverse Resources (다양한 자원으로부터 은의 화학적 침출)

  • Xing, Weidong;Lee, Manseung
    • Journal of the Korean Institute of Resources Recycling
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    • v.26 no.1
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    • pp.3-10
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    • 2017
  • The special properties of silver are often indispensable in the manufacture of advanced materials. Therefore, it is of importance to develop a process to recover silver which is necessary for the production of advanced materials from diverse resources. In this manuscript, the developed processes for the leaching of silver from diverse resources are reviewed. For this purpose, the advantages and disadvantages of using some inorganic acids (nitric and sulfuric acid) and their mixture with other oxidizing agents (ozone, oxygen, hydrogen peroxide and ferric ion) were investigated. Moreover, the leaching of silver with thiourea and thiosulfate was compared over those by inorganic acids in terms of environmental effect.