九州大学大学院工学府 地球システム工学工学専攻資源処理・環境修復工学研究室
Laboratory of MINERAL PROCESSING,
RECYCLING and ENVIRONMENTAL REMEDIATION

JSPSJSPS Core to Core Program conducted by Professor Keiko SASAKI

Advanced Research Network for Biohydrometallurgy of Double Refractory Gold Ore

Objective

In double refractory gold ore (DRGO), fine gold particles are confined in sulfide minerals that are difficult to decompose, and graphitic shale coexists, so 30 to 70% of the recovery loss of gold would be caused in cyanidation. Therefore, despite the higher gold contents than the average, the development of DRGO has been abandoned.

DRGOs are distributed in various regions, but especially in the West Africa region, carbonaceous matter is often removed by roasting, which not only causes air pollution but also does not completely remove carbon. However, carbon content with a high specific surface area that adsorbs and loses Au(CN)2- such as activated carbon remains, and the problem has not been solved yet.

DRGOs in West Africa have high carbon contents but high grades of gold, so the application of bio-treatment is great significantly effective. From the studies of the applicants in the past, it is known that DRGO can obtain a certain gold recovery rate by oxidative decomposition of sulfide minerals by iron-oxidizing bacteria and subsequent crude enzyme treatment containing lignin-degrading enzyme. The proof is being clarified by a joint research with South Africa using the quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN).

By establishing the academic foundation of the Asia-Africa Science Platforms, the bio-treatment guidelines for DRGO and its theoretical support can be obtained, and academic exchanges and people-to-people exchanges between resource-rich and non-resource-rich countries can be promoted. Therefore, it is possible to contribute to the economic development of gold resource countries in West Africa and to develop the recovery technology of precious metals from urban mines in developed countries by making full use of environment-friendly bio-treatment without depending on high temperature and high pressure conditions.

Young researchers involved in this project are strongly encouraged to make presentations at the Biohydrometallurgy held every other year or the International Biohydrometallurgy Symposium (IBS), and will promote joint research and seminars with the aim of creating a platform for bio-treatment of DRGO. From the perspective of fostering young researchers involved in this project, not only young faculty members but also doctoral graduate students and postdocs will be able to stay for a long time with each other.

MEMBERS

Japan
Name Institution Title
Keiko Sasaki Kyushu University Professor
Yuichi Sugai Professor
Naoko Okibe Associate Professor
Hajime Miki Associate Professor
Hirofumi Ichinose Associate Professor
Kojo Twum Konadu Postdoctoral fellow
Binglin Guo Postdoctoral fellow
Postgraduates x 3 Student
Takashi Kaneta Okayama University Professor
South Africa
Susan Harrison University of Cape Town Vice president
Megan Becker Associate Professor
Catherine Edward Postdoctoral fellow
Supratim Biswas Postdoctoral fellow
Didi Makaula Postdoctoral fellow
Elaine Govender Postdoctoral fellow
Sehliselo Ndlovu University of the Witwatersrand Professor
Ghana
Amankwah Richard University of Mining and Technology Vice president
Grace Ofori-Sarpong Associate Professor
Clement Owusu Assistant Professor
Postgraduate x 1 Student
Boateng Onwona-Agyman University of Ghana Dean
Others
Richmond K. Asamoah University of South Australia Postdoctoral fellow

PUBLICATIONS

Paper (2020-)

2022
Ryotaro Sakai, Cindy, Diego Mendoza, Konadu T. Kojo, Cindy, Yuji Aoki, Tsuyoshi Hirajima, Hirofumi Ichinose, Keiko Sasaki, Laccase-mediator system for enzymatic degradation of carbonaceous matter in the sequential pretreatment of extremely refractory gold ore, Hydrometallurgy, 212 (2022)105894, https://doi.org/10.1016/j.hydromet.2022.105894
2021
Cindy, Ryotaro Sakai, Diego Mendoza, Konadu Kojo, Yuji Aoki, Keiko Sasaki, Significance of acid washing after biooxidation of sulfides in sequential biotreatment of extremely refractory gold ore from Syama mine, Mali, Minerals, 11(2021) 1316.
Diego Mendoza, Hirofumi Ichinose, Kojo Konadu, Keiko Sasaki, Degradation of powder activated carbon by laccase mediated system: model experiment for improvement of gold recovery from carbonaceous gold ore, Journal of Environmental Chemical Engineering, Vol.9, Issue 6 (2021) 106375.
Diego M. Mendoza, Kojo T. Konadu, Yuji Aoki, Misato Kameya, Keiko Sasaki, Carbonaceous matter degradation by fungal enzyme treatment to improve Ag recovery from an Au-Ag-bearing concentrate, Minerals Engineering, 163 (2021) 106768, https://doi.org/10.1016/j.mineng.2020.106768
2020
Kojo T. Konadu, Ryotaro Sakai, Diego M.Mendoza, Chitiphon Chuaicham, Hajime Miki, Keiko Sasaki, Effect of carbonaceous matter on bioleaching of Cu from chalcopyrite ore, Hydrometallurgy 195 (2020) 105363 (SI)
Keishi Oyama, Kazuhiko Shimada, Jun-ichiro Ishibashi, Keiko Sasaki, Hajime Miki, Naoko Okibe, Catalytic mechanism of activated carbon-assisted bioleaching of enargite concentrate, Hydrometallurgy, 196 (2020) 105417 (SI)
Kojo T. Konadu, Diego M. M. Flores, Robert J. Huddy, Susan T. L. Harrison, Takashi Kaneta, Keiko Sasaki, Biological pretreatment of carbonaceous matter in double refractory gold ores: a review and some future considerations, Hydrometallurgy, 196 (2020) 105434 (SI)

Book chapter (2020-)

2020
Keiko Sasaki, Kojo T. Konadu, Biotechnological approaches to facilitate gold recovery from double refractory gold ores, in Biotechnology in Mining and Metallurgical Industry, Intech Open DOI: 10.5772/intechopen.94334

Conference Proceedings (2020-)

2022
Ikumi Suyama, Kojo T. Konadu, Yuji Aoki, Keiko Sasaki, Improvement of Au extraction from gold ores by thiourea in the presence of a reductant (awarded), MMIJ Kyushu spring 2022
Cindy, Ryotaro Sakai, Richmond Asamorh, Mendoza Diego, Kojo Konadu, Keiko Sasaki, Effects of lignin-degrading enzyme treatment on carbonaceous matter degradation in double refractory gold ores, MMIJ 2022 spring, online.
Diego Mendoza, Keiko Sasaki, Trace analysis of gold in double refractory gold ores by ICP-OES, MMIJ 2022 spring, online.
2021
D.X Makaula, K Konadu, E Opitz, K Sasaki, S.T.L Harrison, Using flotation to concentrate potential double refractory gold ores: A precursor study towards biooxidation of sulfide matrix and fungal decomposition of carbonaceous matter, Flotation’21, (2021) November.
D.X Makaula, K Konadu, E Opitz, M Smart, K Sasaki, S.T.L Harrison, Investigating the impact of temperature on the degradation of sulfide matrix during the biooxidation of potential double refractory gold concentrates, CINEST 2021 (2021) November.
D.X Makaula, K Konadu, E Opitz, M Smart, K Sasaki, S.T.L Harrison, Using flotation to concentrate potential double refractory gold ores: A precursor study towards biooxidation of sulfide matrix and fungal decomposition of carbonaceous matter, CINEST 2021 (2021) November.
Cindy, Diego M. M. Flores, Kojo T. Konadu, Hirofumi Ichinose, Keiko Sasaki, Effects of common heavy metals on laccase activity and stability for enzymatic degradation of carbonaceous matter in double refractory gold ores, CINEST 2021, (2021) November.
Clement Owusu, Selorm Mensah, Konadu Kojo Twum, Grace Ofori-Sarpong, Keiko Sasaki, Richard K. Amankwah, Improving gold recovery in carbonaceous gold ores using naphtalene sulphonate as blanking agent, CINEST 2021 (2021) November.
Diego M. Mendoza, Hirofumi Ichinose, Keiko Sasaki, Study on laccase-mediator system to degrade carbonaceous matter surrogate for minimization of gold recovery loss in refractory gold ores, CINEST 2021 (2021) November.
Ryotaro Sakai, Cindy, Kojo. T Konadu, Diego M. Mendoza, Keiko Sasaki, Sequential biotreatment of extremely refractory gold ores using laccase, CINEST 2021 (2021) November.
Grace Ofori-Sarpong, Clement Owusu, Richard Kwasi Amankwah, Advances in the use of Phanerochaete chrysosporium in Mycohydrometallurgical Pretreatment of Double Refractory Gold Ores: A Review of Preg-Robbing Reduction of Carbonaceous Materials, CINEST 2021 (2021) November.
2020
Diego M. Mendoza, Kojo T. Konadu, Hirofumi Ichinose, Keiko Sasaki, Degradation of powder activated carbon by laccase mediated system: model experiment for improvement of gold recovery from carbonaceous gold ore, Proc. International Symposium on Earth Science and Technology 2020
Kojo T. Konadu, Keiko Sasaki, Review of the double refectory gold ore pretreatment by lignin-degrading enzymes to minimize preg-robbing, Proc. International Symposium on Earth Science and Technology 2020
Ryotaro Sakai, Kojo T. Konadu, Keiko Sasaki, Effect of carbonaceous matter on bioleaching of chalcopyrite. Proc. MMIJ Kyushu spring, 2020

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