Two-step processing of refractory gold-containing sulfidic concentrate via biooxidation at two temperatures
- 50 Downloads
A practical problem in the biohydrometallurgical processing of sulfide raw materials is the need to increase the efficiency and stability. The heating of pulp in bioreactors causes exothermic lysis of microorganisms and cessation of the production process. To find solutions to these problems, the present study examines the biooxidation of a gold-bearing sulfidic concentrate in a two-step (ferric leaching + biooxidation) process with different temperatures in the bioreactors at the biological step: 50 °C in the first bioreactor and 39 °C in the second. The main minerals of the flotation concentrate were pyrrhotite, pyrite, arsenopyrite, and stibnite. The preliminary ferric leaching of the concentrate for 5 h at 80 °C and pH 1.15–1.35 allowed oxidization of 26.8% of arsenopyrite and 54.4% of sulfur in the sulfides. At the biological step, a moderately thermophilic culture of acidophilic microorganisms dominated by representatives of the genus Sulfobacillus was used. The residence time of the pulp in each bioreactor was 2 days with a total residence time of 4 days. This study indicated that the efficiency of two-step process with the use of a two-temperature mode is comparable with the constant temperature mode and much higher than that of the one-step process. The final oxidation levels of arsenopyrite and sulfidic sulfur for the two-step process with elevated temperature in the primary bioreactor were 73.1 and 65.9%, respectively, with 82% gold recovery.
KeywordsBiooxidation Ferric leaching Sulfidic concentrate Acidophilic microorganisms Two-step process Two-temperature mode
The work was supported by Federal Agency for Scientific Organizations, Russia [project no. 0104-2014-0108].
Compliance with ethical standards
Conflict of interest
The author declares that he has no conflicts of interest.
- Bosecker K (1997) Bioleaching: metal solubilization by microorganisms. FEMS Microbiol Rev 20:591–604. https://doi.org/10.1111/j.1574-6976.1997.tb00340.x Google Scholar
- Davis DG, Jacobsen WR (1960) Determination of iron and iron–aluminum mixtures by titration with EDTA. Anal Chem 32(2):215–217Google Scholar
- Dew DW, Lawson EN, Broadhurst JL (1997) The BIOX® process for biooxidation of gold-bearing ores or concentrates. In: Rawlings DE (ed) Biomining: theory, microbes and industrial processes. Springer, Berlin, pp 45–80Google Scholar
- Fang F, Zhong H, Jiang F, Luo Z, Sun X, Xu K (2013) Effect of pyrite on bioleaching of arsenopyrite. Chin J Nonferrous Met 23(10):2970–2976Google Scholar
- Filippova NA (1975) Phazovy analiz rud i produktov ikh pererabotki. Khimiya, Moscow (in Russian) Google Scholar
- Gericke M (2015) Base metal tank bioleaching: from laboratory test work to commercialization. Adv Mater Res 1130:197–200. https://doi.org/10.4028/www.scientific.net/AMR.1130.197 Google Scholar
- Haffty J, Riley LB, Gross WD (1977) A manual of fire assaying and determination of the noble metals in geological materials. Geol Surv Bull 1445:1–58Google Scholar
- Johnson DB (1998) Biodiversity and ecology of acidophilic microorganisms. FEMS Microbiol Ecol 27:307–317. https://doi.org/10.1111/j.1574-6941.1998.tb00547.x Google Scholar
- Kondrat’eva TF, Pivovarova TA, Tsaplina IA, Fomchenko NV, Zhuravleva AE, Murav’ev MI, Melamud VS, Bulayev AG (2012) Diversity of the communities of acidophilic chemolithotrophic microorganisms in natural and technogenic ecosystems. Microbiology 81(1):1–24. https://doi.org/10.1134/S0026261712010080 Google Scholar
- Melamud VS, Pivovarova TA, Kondrat’eva TF, Karavaiko GI (1999) Study of oxidation by bacteria of a difficult-to-dress gold-containing pyrite–arsenopyrite concentrate under moderately thermophilic conditions. Appl Biochem Microbiol 35(2):161–167Google Scholar
- Natarajan KA (2018) Biotechnology of metals: principles, recovery methods and environmental concerns. Elsevier Inc., AmsterdamGoogle Scholar
- Ostroumov EA, Ivanov-Emin BN (1945) Metody opredeleniya sery. Mosgeoltekhizdat, Moscow (in Russian) Google Scholar
- Silverman MP, Lundgren DG (1959) Studies on the chemoautotrophic iron bacteria Ferrobacillus ferrooxidans. An improved medium and harvesting procedure for securing high yields. J Bacteriol 77:642–647Google Scholar
- Tuovinen OH, Bhatti TM, Bigham JM, Garcia O, Lindstrom EB (1994) Oxidative dissolution of arsenopyrite by mesophilic and moderately thermophilic acidophiles. Appl Environ Microbiol 60:3268–3274Google Scholar