Bioleaching of Copper Sulphide Ore by a Microbial Consortium Isolated from Acid Mine Drainage: Influence of [Fe²⁺]

Abstract:

Peru is mining country with a great diversity of mineral resource. The high grade ores are declining, and there is a need to implement new techniques for recycling metals (Cu, Au, Zn, Pb, etc) from low-grade ores. In order to answer this question, the bioleaching of copper from sulphide ore (FeS₂ 45.30%, CuFeS₂ 1.90%, ZnS 8.90%, FeAsS 13.12%, PbS 3.69%) was evaluated with different concentrations of Fe²⁺ using an iron-oxidizing native microbial consortium.The samples were collected from drainage acid mine (4100 m.a.s.l.) located in the south of Huancavelica region and the sample of ore from middle Huaraz region (3200 m.a.s.l.). Microorganisms were isolated in 9k medium at pH 1.8, 22oC. Bioleaching test were performed in two consecutive steps to 150 rpm at 22oC, monitoring pH, ORP (mV). Assays varying the concentration of Fe²⁺ (0 mM – 53 mM) were performed with a pulp density of 1% and 2% at each step, and with an inoculum 10% (v/v) to a microbial concentration of 10⁸ cel/mL.We isolated a microbial consortium after 8 weeks with presence of bacteria Acidithiobacillus ferrooxidans-like. In assays, copper was solubilized. The microbial concentration in the tests was (2x10⁷- 4x10⁷cel/mL). In the first stage, the test with 21 mM Fe²⁺ recovered 62% copper. In the next step, with the bacterial concentration of the first step, bioleaching time is reduced by 22% for copper recovery (63%) in absence of Fe²⁺.With these data, we observed that the addition of iron is not necessary in a stage adaptation when the mineral contain iron.

• Periodical: Advanced Materials Research (Volume 1130)
• Pages: 418-422
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1130.418
• Online since: November 2015
• Authors: Luis Salcedo-Mejía*, Luis Ramírez-Osco, Hans Cayo-Gonzales, Vladimir Arias-Arce
• Keywords: Bioleaching, Copper Sulphide, Microbial Consortium, Perú

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