Electrochemical Behavior of Carbon Paste Electrode with Gold-Bearing Pyrite in Bioleaching

Article Preview

Abstract:

The dissolution of gold-bearing pyrite plays an important role in bioleaching of gold. This paper describes a fundamental study on the electrochemical behavior and reaction mechanisms of gold-bearing pyrite leaching in the form of Carbon Paste Electrode (CPE) with and without microorganisms using Cyclic Voltammetry (CV) and polarization curve. A two step process was suggested from Cyclic voltammetry. Electrode passivation by elemental sulphur was observed below 700mV (vs. SCE), elemental sulphur was then oxidized to sulphate when the electrode potential further increased from 700mV. The polarization current density of CPE and the oxidation rate of pyrite are further enhanced by the presence of microorganisms. Analyses of EDS and XPS confirmed the formation of elemental sulphur and sulphate. This electrochemical method successfully showed its simplicity and reliability to measure oxidation rate of gold bearing pyrite.

You might also be interested in these eBooks

Info:

Periodical:

Pages:

360-363

Citation:

Online since:

October 2013

Export:

Price:

[1] M. Descostes, P. Vitorge, C. Beaucaire, Pyrite dissolution in acidic media. Geochimica et Cosmochimica Acta, 2004, (68): 4559-4569.

DOI: 10.1016/j.gca.2004.04.012

Google Scholar

[2] A.P. Chandra, A.R. Gerson, The mechanisms of pyrite oxidation and leaching: A fundamental perspective. Surface Science Reports, 2010, (9): 293-315.

DOI: 10.1016/j.surfrep.2010.08.003

Google Scholar

[3] X.X. Tao, G.Q. Gong, J.Y. Liu, J. Mei, Z.Q. Chen, J.Z. Chen, Electrochemical mechanism of coal biodesulphurization. Journal of China University of Mining and Technology, 2007, (36): 431-435(in Chinese).

Google Scholar

[4] H.X. Li, D.Z. Wang, Electrochemistry of sulfide bio-Leaching (I). Mining and Metallurgy, 2002, (11): 49-53(in Chinese).

Google Scholar

[5] R. Liu, A.L. Wolfe, D.A. Dzombak, C.P. Horwitz, B.W. Stewart, R.C. Capo, Electrochemical study of hydrothermal and sedimentary pyrite dissolution. Applied Geochemistry, 2008, (23): 2724-2734.

DOI: 10.1016/j.apgeochem.2008.06.005

Google Scholar

[6] G.H. Gu, X.J. Sun, K.T. Hu, J.H. Li, G.Z. Qiu, Electrochemical oxidation behavior of pyrite bioleaching by Acidthiobacillus ferrooxidans. Trans. Nonferrous Met. Soc. China, 2012, (22): 1250-1254.

DOI: 10.1016/s1003-6326(11)61312-5

Google Scholar

[7] Q. Li, Y.B. Yang, T. Jiang, G.Z. Qiu, Electrochemical oxidation of arsenopyrite in acidic media. The Chinese Journal of Nonferrous Metals, 2006, (16): 1971-(1975).

Google Scholar

[8] H.K. Lin, W.C. Say, Study of pyrite oxidation by cyclic voltammetric, impedance spectroscopic and potential step techniques. Journal of Applied Electrochemistry, 1999, (29): 987-994.

Google Scholar

[9] T.A. Fowler, F.K. Crundwell, On the kinetics and mechanism of the dissolution of pyrite in the presence of Thiobacillus ferroxidans. Hydrometallurgy, 2001, (3): 257-270.

DOI: 10.1016/s0304-386x(00)00172-9

Google Scholar