Effect of Temperature on Column Bioleaching of a Refractory Gold Ore

Abstract:

Low-grade, finely disseminated refractory sulfide gold ores associated with high arsenic are ubiquitous resources all over the world. Since heap bio-oxidation is an economic and promising biotechnology to recover gold, low grade, high organic carbon and arsenic bearing gold ores from Zhesang Mines in China were chosen for this purpose to study the key factors that would affect biooxidation. Pyrite and arsenopyrite (particle size 0.002-0.22 mm) were the main minerals from Mineral Liberation Analysis (MLA). Column biooxidation and cyanidation of mineral size < 10 mm were evaluated for its potential for gold extraction. Results showed that temperature was the main factor influencing sulfide oxidation. 58-67 % of sulfide was oxidized at 35-45°C after > 240 days of biooxidation with mixed mesophiles, while higher sulfide-S dissolution (77%) was obtained at 60°C. Sulfide-S fraction distribution revealed higher mineral decomposition, finer fractions and eventually higher sulfide oxidation at 60°C. Jarosite and scorodite were found from the residues at 60°C by SEM and EDX, which implies higher temperature accelerated arsenic precipitation. No elemental sulfur was detected during the biooxidation at 35-60°C. After bio-oxidation, column cyanidation was successfully demonstrated recovery of gold from the residues, with gold extraction rate reaching 66%.

• Periodical: Advanced Materials Research (Volume 825)
• Pages: 352-355
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.825.352
• Online since: October 2013
• Authors: Zeng Ling Wu, Zhong Sheng Huang, Ren Man Ruan, Shui Ping Zhong, Brenda K.C. Chan
• Keywords: Bio-Oxidation, Cyanidation, Pyrite, Refractory Gold Ore, Scorodite, Sulfide Oxidation

References

[1] P. Bhakta, B. Arthur, Heap bio-oxidation and gold recovery at Newmont mining: first-year results. Journal of Metals, 2002, 31-34.

DOI: 10.1007/bf02709218

[2] K. Tempel, Commercial biooxidation challenges at Newmont's Nevada operations. In: 2003 SME Annual Meeting, Preprint 03-067, Soc Mining, Metallurgy and Exploration, Littleton, Colo.

[3] G. J. Olson, J. A. Brierley, C. L. Brierley, Bioleaching review part B: Progress in bioleaching: applications of microbial processed by the minerals industries. Appl. Microbiol. Biotechnol., 2003, (63): 249-257.

DOI: 10.1007/s00253-013-5095-3

[4] X.Y. Liu, B.W. Chen, J.K. Wen, Dominace of Acidithiobacillus at ore surface of Zijinshan commercial low-grade copper bioleaching heap. Trans. Nonferrous Met. Soc. China, 2008(18): 1506-1512.

DOI: 10.1016/s1003-6326(09)60033-9

[5] J. A. Brierley, Response of microbial systems to thermal stress in bio-oxidation heap pretreatment of refractory gold ores. Hydrometallurgy, 2003, (71): 13-19.

DOI: 10.1016/s0304-386x(03)00143-9