Flotation behavior of native gold and gold-bearing sulfide minerals in a polymetallic gold ore

Abstract

In this study, the flotation behaviors of gold and gold-associated sulfide minerals (pyrite and sphalerite) in a polymetallic sulfide gold ore were investigated using flotation kinetics parameters. It was found that high gold recovery (>90%) can be achieved by the selective flotation of pyrite and sphalerite. However, the sphalerite flotation results showed that sphalerite could not be separated from pyrite with a high selectivity (selectivity index∼1), because of insufficient depression of pyrite (with high alkaline medium and/or using a depressant). Even if more selective separation was achieved from the pyrite flotation (selectivity index∼5), 40% of sphalerite in the ore was transferred into the pyrite concentrate. In addition, the results of the collectorless tests indicated that more than 80% of the gold can be recovered, and higher selectivity indexes (up to 10) are achievable. Analysis of the particle size distribution of the collectorless flotation concentrate showed that the amount of −40 μm in the concentrate was 90%.

In conclusion, a gold concentrate containing low sulfur (10.8%) with a gold recovery of greater than 95% is achievable from a two-stage flow sheet (collectorless flotation as the rougher stage and pyrite flotation as the scavenger stage).

Keywords:

• Gold ore
• sphalerite
• pyrite
• froth flotation
• entrainment
• kinetics

Acknowledgements

The authors would like to thank Dr. Hasan Ciftci, Dr. Fatma Gurbuz and Dr. Sermin G. Karagoz for the valuable support provided in carrying this study.

Additional information

Funding

The authors gratefully acknowledge the financial support of the Scientific and Technological Research Council of Turkey [TUBITAK; Project No: 116M712] and Scientific Research Projects Funding Unit of the Suleyman Demirel University (Project No: FYL-2019-7068) which made this work possible.