Share This Article:

Suppression of Pyrite Oxidation by Surface Silica Coating

Abstract Full-Text HTML Download Download as PDF (Size:571KB) PP. 37-43
DOI: 10.4236/gep.2014.24006    2,747 Downloads   3,864 Views   Citations

ABSTRACT

The exposure of pyrite (FeS2) to atmospheric conditions during mining activity causes a series of complex oxidation reactions, resulting to acid generation and the subsequent release of toxic heavy metals in the surrounding aquatic and terrestrial ecosystems. The produced acidic mine waters, known as acid mine drainage (AMD), constitute one the major environmental problems of both operating and abandoned mixed sulphide, coal and other mine sites where sulphidic minerals are encountered. A sustainable approach to the environmentally safe pyrite-bearing extractive waste management is related to the prevention of oxidation by developing artificial coatings on the pyrite surfaces. In this study, experiments performed to study the conditions of the silica coating formation on the FeS2 particles contained in a pyrite concentrate are presented. Batch tests involving the treatment of pyrite samples with a coating solution, consisting of Na2SiO3, H2O2 and buffered pH, were performed under a liquid to solid ratio (L/S) 100 l/kg. The effect of parameters including SiO2 concentration (5 - 50 mM), pH values (5.0 - 8.0) and contact time up to 24 hours, was investigated. Parameters examined to monitor the silica coating formation process include analysis of Fe, Si,  and H2O2 in the aqueous phase. Scanning electron microscopy with energy dispersive spectrometry (SEM/EDS) was used for the examination of the chemically modified surfaces of silica-treated pyrite samples.

Conflicts of Interest

The authors declare no conflicts of interest.

Cite this paper

Kollias, K. , Mylona, E. , Adam, K. , Papassiopi, N. , Papassiopi, N. and Xenidis, A. (2014) Suppression of Pyrite Oxidation by Surface Silica Coating. Journal of Geoscience and Environment Protection, 2, 37-43. doi: 10.4236/gep.2014.24006.

References

[1] Alexander, G. B. (1954). The Polymerization of Monosilicic Acid. Journal of the American Chemical Society, 76, 2094- 2096. http://dx.doi.org/10.1021/ja01637a017
[2] Bessho, M., Wajima, T., Ida, T., & Nishiyama, T. (2011). Experimental Study on Prevention of Acid Mine Drainage by Silica Coating of Pyrite Waste Rocks with Amorphous Silica Solution. Environmental Earth Sciences, 64, 311-318. http://dx.doi.org/10.1007/s12665-010-0848-0
[3] Elsetinow, A., Borda, M., Schoonen, M. A., & Strongin, D. R. (2003). Suppression of Pyrite Oxidation in Acidic Aqueous Environments Using Lipids Having Two Hydrophobic Tails. Advances Environmental Research, 7, 969-974. http://dx.doi.org/10.1016/S1093-0191(02)00101-6
[4] Evangelou, V. P. (1996). Oxidation Proof Silicate Surface Coating on Iron Sulfides. U.S. Patent, Patent Number 5,494,703.
[5] Evangelou, V. P. (1995a). Potential Microencapsulation of Pyrite by Artificial Inducement of Ferric Phosphate Coatings. Journal of Environmental Quality, 24, 535-542. http://dx.doi.org/10.2134/jeq1995.00472425002400030021x
[6] Evangelou, V. P. (1995b). Pyrite Oxidation and Its Control. Boca Raton, FL: CPC Press.
[7] Evangelou, V. P. (2001). Pyrite Microencapsulation Technologies: Principles and Potential Field Application. Ecological Engineering, 17, 165-178. http://dx.doi.org/10.1016/S0925-8574(00)00156-7
[8] Glover, R. (2007). Permanganate Passivation of Pyrite Containing Ores: Scale up and Characterization. MS Thesis, Reno: University of Nevada.
[9] Herbillon, A. J., & Tran Vinh An, J. (1969). Heterogeneity in Silicon-Iron Mixed Hydroxides. Journal of Soil Science, 20, 223-235. http://dx.doi.org/10.1111/j.1365-2389.1969.tb01569.x
[10] Huminicki, D. M. C., & Rimstidt, J. D. (2009). Iron Oxyhy-droxide Coating of Pyrite for Acid Drainage Control. Applied Geochemistry, 24, 1626-1634. http://dx.doi.org/10.1016/j.apgeochem.2009.04.032
[11] Iler, R. K. (1979). The Chemistry of Silica: Solubility, Polymerization, Colloid and Surface Properties and Biochemistry of Silica. New York, NY: John Wiley and Sons.
[12] Kargbo, D. M., Atallah, G., & Chatterjee, S. (2004). Inhibition of Pyrite Oxidation by a Phospholipid in the Presence of Silicate. Environmental Science Technology, 38, 3432-3441. http://dx.doi.org/10.1021/es0352552
[13] Lalvani, S. B., Zhang, G., & Lalvani, L. S. (1996). Coal Pyrite Passivation Due to Humic Acids and Lignin Treatment. Fuel Science and Technology International, 14, 1291-1313. http://dx.doi.org/10.1080/08843759608947640
[14] Lin, S. S., & Gurol, M. D. (1998). Catalytic Decomposition of Hydrogen Peroxide on Iron Oxide: Kinetics, Mechanism, and Implications. Environmental Science and Technology, 32, 1417-1423. http://dx.doi.org/10.1021/es970648k
[15] McKibben, M. A., & Barnes, H. L. (1986). Oxidation of Pyrite in Low Temperature Acidic Solutions: Rate Laws and Surface Textures. Geochimica et Cosmochimica Acta, 50, 1509-1520. http://dx.doi.org/10.1016/0016-7037(86)90325-X
[16] Schenk, J. E., & Weber Jr., W. J. (1968). Chemical Interactions of Dissolved Silica with Iron(II) and (III). Journal of the American Water Works Association, 2, 199-212.
[17] Schwertmann, U., & Cornell, R. M. (1991). Iron Oxides in the Laboratory. Preparation and Characterization. VCH Verlagsgesellschaft, Weinheim.
[18] Singer, P. C., & Stumm, W. (1970). Acid Mine Drainage: The Rate-Determining Step. Science, 167, 1121-1123. http://dx.doi.org/10.1126/science.167.3921.1121
[19] Sjoberg, S. (1996). Silica in Aqueous Environments. Journal of Non-Crystalline Solids, 196, 51-57. http://dx.doi.org/10.1016/0022-3093(95)00562-5
[20] Swedlund, P. J., & Webster, J. G. (1999). Adsorption and Polymerization of Silicic Acid on Ferrihydrite, and Its Effect on Arsenic Adsorption. Water Research, 33, 3413-3422. http://dx.doi.org/10.1016/S0043-1354(99)00055-X
[21] Swedlund, P. J., Sivaloganathan, S., Miskelly, G. M., & Water-house, G. I. N. (2011). Assessing the Role of Silicate Polymerization on Metal Oxyhydroxide Surfaces Using X-Ray Photoelectron Spectroscopy. Chemical Geology, 285, 62-69. http://dx.doi.org/10.1016/j.chemgeo.2011.02.022
[22] Zhang, Y. L., & Evangelou, V. P. (1998). Formation of Ferric Hydroxide-Silica Coatings on Pyrite and Its Oxidation Behavior. Soil Science, 163, 53-62. http://dx.doi.org/10.1097/00010694-199801000-00008

  
comments powered by Disqus

Copyright © 2019 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.