Bacterial Cyanide Generation in the Presence of Metal Ions (Na+, Mg2+, Fe2+, Pb2+) and Gold Bioleaching from Waste PCBs

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Author(s)

    • Tran Chi Dac
    • University of Science and Technology (UST), Korea|Korea Institute of Geoscience and Mineral Resources (KIGAM)
    • Lee Jae-Chun
    • Korea Institute of Geoscience and Mineral Resources (KIGAM)
    • Pandey Banshi Dhar
    • Korea Institute of Geoscience and Mineral Resources (KIGAM)|National Metallurgical Laboratory (NML), Council of Scientific and Industrial Research, India
    • Jeong Jinki
    • Korea Institute of Geoscience and Mineral Resources (KIGAM)
    • Yoo Kyoungkeun
    • Department of Energy and Resources Engineering, Korea Maritime University
    • Huynh Trung Hai
    • Institute for Environmental Science and Technology, Hanoi University of Science and Technology

Abstract

As an alternative using cyanide chemicals for gold extraction, the application of a cyanogenic bacterium <i>viz.</i> <i>Chromobacterium violaceum</i> (<i>C. violaceum</i>) in YP medium has been investigated. The catalytic roles of metal ions such as Na<sup>+</sup>, Mg<sup>2+</sup>, Fe<sup>2+</sup>, and Pb<sup>2+</sup>, as well as the effect of Na<sub>2</sub>HPO<sub>4</sub> nutrient addition on the cyanide generation efficiency of the bacterium in this medium have been elucidated. While MgSO<sub>4</sub> and FeSO<sub>4</sub> added to the medium were equally effective for cyanide generation, improved efficiency was obtained in the presence of Na<sub>2</sub>HPO<sub>4</sub> and Pb(NO<sub>3</sub>)<sub>2</sub>. In order to examine the effectiveness of <i>C. violaceum</i> cultured in YP medium for the generation of cyanide ions, the dissolution of gold and copper from waste mobile phone printed circuit boards (PCBs), a good source of gold and copper in alkaline conditions, was tested at 30°C, for various pH values and metal ion contents. Gold leaching was found to be 11% in 8 d at pH 11.0 in presence of 4.0 × 10<sup>−3</sup> mol/L MgSO<sub>4</sub>, whereas; copper recovery was high (11.4%) at pH 10.0. Addition of 1.0 × 10<sup>−2</sup> mol/L Na<sub>2</sub>HPO<sub>4</sub> and 3.0 × 10<sup>−6</sup> mol/L Pb(NO<sub>3</sub>)<sub>2</sub> to the YP medium increased copper leaching to 30.3% and 38.1%, respectively, at pH 10.0 in 8 d. However, this effect was not observed for gold leaching.

Journal

  • JOURNAL OF CHEMICAL ENGINEERING OF JAPAN

    JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 44(10), 692-700, 2011

    The Society of Chemical Engineers, Japan

Codes

  • NII Article ID (NAID)
    130000780084
  • Text Lang
    ENG
  • ISSN
    0021-9592
  • Data Source
    J-STAGE 
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