SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2019, Vol. 27 ›› Issue (5): 1184-1190.DOI: 10.1016/j.cjche.2018.08.006

• Energy, Resources and Environmental Technology • Previous Articles     Next Articles

Mineral phase and structure changes during roasting of fine-grained carbonaceous gold ores and their effects on gold leaching efficiency

Jianping Jin1,2, Yuexin Han1, Hui Li3, Yangyang Huai4, Yongjun Peng4, Xiaotian Gu1, Wei Yang3   

  1. 1 School of Resources & Civil Engineering, Northeastern University, Shenyang 110819, China;
    2 Xi'an Northwest Geological Institute Company of Nonferrous Metals Co., Ltd., Xi'an 710054, China;
    3 College of Material and Resource, Xi'an University of Architecture and Technology, Xi'an 710055, China;
    4 School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane 4072, Australia
  • Received:2018-07-01 Revised:2018-08-07 Online:2019-06-27 Published:2019-05-28
  • Contact: Jianping Jin
  • Supported by:
    Supported by the National Natural Science Foundation of China (51704059, 51474169).

Mineral phase and structure changes during roasting of fine-grained carbonaceous gold ores and their effects on gold leaching efficiency

Jianping Jin1,2, Yuexin Han1, Hui Li3, Yangyang Huai4, Yongjun Peng4, Xiaotian Gu1, Wei Yang3   

  1. 1 School of Resources & Civil Engineering, Northeastern University, Shenyang 110819, China;
    2 Xi'an Northwest Geological Institute Company of Nonferrous Metals Co., Ltd., Xi'an 710054, China;
    3 College of Material and Resource, Xi'an University of Architecture and Technology, Xi'an 710055, China;
    4 School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane 4072, Australia
  • 通讯作者: Jianping Jin
  • 基金资助:
    Supported by the National Natural Science Foundation of China (51704059, 51474169).

Abstract: While roasting has been widely applied to reduce the negative effect of carbonaceous matters on gold extraction from fine-grained carbonaceous gold ores, the phase and structure changes of minerals during roasting and their influences on the leaching rate of gold have not been fully understood. This limits the extraction of carbonaceous gold deposits. The current work examines the oxidation process of a fine-grained carbonaceous gold ore during roasting using a range of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive Spectrometer (EDS) analysis and pore structure analysis together with gold leaching tests. The results show that during the process of oxidative roasting, the carbonaceous matters (organic carbon and graphitic carbon) and pyrite were completely decomposed at 600℃ with the carbonaceous components burned and pyrite oxidized into hematite. At 650℃, while dolomite was decomposed into calcia, magnesia, calcium sulfate etc., the calcine structure became loose and porous, leading to a high gold leaching rate from the roasted product. Above 750℃, the porous calcite structure started to collapse along with the agglomeration, leading to the secondary encapsulation of gold particles, which contributed to the sharp drop in the gold leaching rate of the roasted product. This study suggests optimum phase and structure changes of minerals during roasting to achieve maximum gold extraction from fine-grained carbonaceous gold deposits.

Key words: Carbonaceous gold ore, Roasting, Leaching, X-ray diffraction (XRD), Scanning electron microscopy (SEM)

摘要: While roasting has been widely applied to reduce the negative effect of carbonaceous matters on gold extraction from fine-grained carbonaceous gold ores, the phase and structure changes of minerals during roasting and their influences on the leaching rate of gold have not been fully understood. This limits the extraction of carbonaceous gold deposits. The current work examines the oxidation process of a fine-grained carbonaceous gold ore during roasting using a range of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive Spectrometer (EDS) analysis and pore structure analysis together with gold leaching tests. The results show that during the process of oxidative roasting, the carbonaceous matters (organic carbon and graphitic carbon) and pyrite were completely decomposed at 600℃ with the carbonaceous components burned and pyrite oxidized into hematite. At 650℃, while dolomite was decomposed into calcia, magnesia, calcium sulfate etc., the calcine structure became loose and porous, leading to a high gold leaching rate from the roasted product. Above 750℃, the porous calcite structure started to collapse along with the agglomeration, leading to the secondary encapsulation of gold particles, which contributed to the sharp drop in the gold leaching rate of the roasted product. This study suggests optimum phase and structure changes of minerals during roasting to achieve maximum gold extraction from fine-grained carbonaceous gold deposits.

关键词: Carbonaceous gold ore, Roasting, Leaching, X-ray diffraction (XRD), Scanning electron microscopy (SEM)