ObjectivesIn 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.