Water Washing of Fungal-treated Carbonaceous Ores: Effect on Aurocyanide Adsorption by Activated Carbon in CIL Circuit

  • Richard Kwasi Amankwah University of Mines and Technology, Tarkwa
  • Grace Ofori-Sarpong University of Mines and Technology, Tarkwa
  • Abigail Ewoenam Adzigbli University of Mines and Technology, Tarkwa
Keywords: Carbonaceous Gold Ore, Carbon-In-Leach, Cell-free Extracts, Phanerochaete chrysosporium

Abstract

A typical challenge encountered on most gold processing plants during leaching of refractory ores is the reduction in recovery due to the presence of carbonaceous matter which preg-robs dissolved gold, thus reducing overall recovery. To reduce preg-robbing during cyanidation, carbonaceous matter has to undergo pretreatment to passivate the active surface. The fungus, Phanerochaete chrysosporium has been shown to possess the ability to biotransform carbonaceous matter, thus reducing its ability to preg-rob gold. However, the possible transfer of entrained fungal biomass into Carbon-In-Leach (CIL) circuits has been reported to decrease the activity of activated carbon, and a proposed solution to this was to wash the fungal-treated material thoroughly with sufficient water prior to CIL operation. This paper therefore set out to assess the effect of sufficient water washing on aurocyanide adsorption by activated carbon in CIL following fungal pretreatment of carbonaceous ores. To realise the objective, activated carbon was contacted with cell-free extract of P. chrysosporium under varying conditions of pH and time, after which it was washed with different volumes of water, and its gold-adsorption ability assessed.  The results revealed a decrease in the activity of activated carbon as a function of increasing contact time with the cell-free extract. The percentage decrease was higher after treatment in the acidic medium (13%) than the basic medium (9%). After washing the carbon (treated in acidic medium) with various volumes of water, gold adsorption was found to increase directly with the volume of water used from 64% at 0 ml to 84% at 500 ml and 91% at 1000 ml. Correspondingly, the carbon treated in basic medium recorded 69% at 0 ml to 87% at 500 ml and 93% at 1000 ml. This paper thus concludes that, sufficient water washing should be employed after fungal-biotransformation of refractory ores before the material is transferred into the CIL circuit to decrease the effect of entrained biomass on the adsorption capacity of activated carbon.

Author Biographies

Richard Kwasi Amankwah, University of Mines and Technology, Tarkwa
Professor of Minerals Engineering
Grace Ofori-Sarpong, University of Mines and Technology, Tarkwa
Associate Professor of Minerals Engineering
Abigail Ewoenam Adzigbli, University of Mines and Technology, Tarkwa
Student, Minerals Engineering

References

Adam, A. S., Ofori-Sarpong, G. and Amankwah, R. K., (2017), “Assessing the Challenges in the Extraction of Gold from Bacterial-Treated Double-Refractory Concentrate”, SME Annual Meeting, Denver, USA, pp 1-7.

Adams, M. D., Burger, A. M., (1998), “Characterization and blinding of carbonaceous preg-robbers in gold ores”, Minerals Engineering 11 (10), pp. 919-927.

Adams, M. D., Swaney, S. J., Fried, J. and Wagner, F.E., (1996), “Preg-robbing Minerals in Gold ores and residues”, Hidden Wealth. S. African. Inst. Min. and Metall., Johannesburg, pp. 163–172.

Amankwah, R. K. and Yen, W. T. (2006), “Effect of carbonaceous characteristics on biodegradation and preg-robbing behaviour”, In: Onal, G., Acarkan, N., Celik, M. S., Arslan, F., Atesok, G., Guney, A., Sirkecl, A. A., Yuce, A. E., Perek, K. T. (Eds.), Proceedings of the 23rd International Mineral Processing Congress, Promed Advertising Limited, Instanbul, pp. 1445-1451.

Amankwah, R.K., Yen, W.T. and Ramsay, J., (2005), “A Two-Stage Bacterial Pretreatment Process for Double Refractory Gold Ores”, Minerals Engineering, Vol. 18, pp. 103–108.

Andrawis, A., Johnson, K. A. Tien, M., (1988), “Studies on Compound I Formation of the Lignin Peroxidase from Phanerochaete chrysosporium”, The Journal of Biological Chemistry, Vol. 3, pp. 1195-119.

Bhattacharyya, D., Depci, T., Elnathan, F. and Miller, J.D. (2014), “Effect of Activated Carbon Particle Size on The Adsorption/Desorption of Gold from Alkaline Cyanide Solution”, SME Annual Meeting, SME, Salt Lake City, 3pp.

Bonnah, R. C., Ocran, B., Diko, C. S. and Ofori-Sarpong, G. (2016), “Effect of Fungal Treatment on Gold Adsorption by Activated Carbon –A Preliminary Study”, 4th UMaT Biennial International Mining and Mineral Conference, Tarkwa, Ghana, pp. 189-194.

Brierley, C.L. (1997), “Mining biotechnology: research to commercial development and beyond”, In: Biomining: Theory, Microbes and Industrial Processes, Rawlings, D. E. (Ed.), Springer Verlag, Berlin, Germany, pp. 3-17.

Brierley, J. A., Kulpa, C. F., (1993), “Biometallurgical treatment of precious metal ores having refractory carbon content”, US Patent, 5,244,493.

Cecen, F. (2014), “Activated Carbon”, www.researchgate.net/publication/263062486. Assessed: 17th February, 2017.

Helm, M., Vaughan, J., Staunton, W.P., and Avraamides, J. An investigation of the carbonaceous component of preg-robbing gold ores. World Gold Conference 2009, The Southern African Institute of Mining and Metallurgy, 2009.

Hutchins, S. E., Brierley, J. A., Brierley, C. L. (1988), “Microbial pretreatment of refractory sulfide and carbonaceous ores improves the economics of gold recovery”, Mining Engineering, Vol. 40, pp. 249-254.

Ibrado, A. S., Fuerstenau, D.W. (1992), “Effect of the structure of carbon adsorbents on the adsorption of gold cyanide”, Hydrometallurgy, Vol. 30, pp. 243-256.

Madigan, M. T., Martinko, J. M., (2006), Brock’s biology of microorganisms, 11th ed., Pearson Prentice Hall, Upper Saddle River, NJ, pp 469-472, 691-692.

Marsden, J., House, I., (2006), The chemistry of gold extraction, 2nd ed., Society for Mining, Metallurgy and Exploration, Inc. Littleton, Colorado, pp 42-44, 111-126, 161-177, 191-193, 233-263, 297-333.

Ofori-Sarpong, G. and Osseo-Asare, K. (2013), “Preg-robbing of Gold from Cyanide and Non-Cyanide Complexes: Effect of Fungi Pretreatment of Carbonaceous Matter”, International Journal of Mineral Processing, Vol. 119, pp. 27-33.

Ofori-Sarpong, G., Amankwah, R.K., and Osseo-Asare, K. (2013a), “Reduction of Preg-Robbing by Biomodified Carbonaceous Matter–A Proposed Mechanism”, Minerals Engineering, Vol. 42, pp. 29-35.

Ofori-Sarpong, G., Osseo-Asare K., and Tien, M., (2011), “Fungal biotransformation of anthracite-grade carbonaceous matter: Effect on gold cyanide uptake”, In: Biohydrometallurgy: Biotech key to unlock mineral resources value, Proceedings of the 19th International Biohydro-metallurgy Symposium, Qiu, G., Jiang, T., Qin, W., Liu, X., Yang, Y. and Wang, H. (Eds.), Vol. 1, Central South University Press, Changsha, China, pp. 445-451.

Ofori-Sarpong, G., Osseo-Asare K., and Tien, M., (2013b), “Mycohydrometallurgy: Biotransformation of Double Refractory Gold Ores by the Fungus, Phanerochaete chrysosporium”, Hydrometallurgy, Vol. 137, pp. 38 – 44.

Ofori-Sarpong, G., Osseo-Asare K., and Tien, M., (2013c), “Pretreatment of Refractory Gold Ores using Cell-Free Extracts of Phanerochaete chrysosporium: a Preliminary Study”, Advanced Materials Research, Vol. 825, pp. 427-430.

Ofori-Sarpong, G., Tien, M., and Osseo-Asare, K. (2010), “Myco-hydrometallurgy: Coal model for potential reduction of preg-robbing capacity of carbonaceous gold ores using the fungus, Phanerochaete chrysosporium”, Hydrometallurgy 102, 66–72.

Portier, R. J. (1991), “Biohydrometallurgical Processing of Ores, and Microorganisms therefore”, US Patent No. 5,021,088.

Qian LIU, Hong-ying YANG, Lin-lin TONG (2014), “Influence of Phanerochaete chrysosporium degradation and preg-robbing capacity of activated carbon”, Trans. Nonferrous Met. Soc. China, pp. 1905−1911.

Rawlings, D. E. (1998), “Industrial practice and the biology of leaching of metals from ores”, Journal of Industrial Microbiology and Biotechnology, Vol. 20, pp. 268-274.

Rees, K.L. and Van Deventer, J. S. J. (2000), “Preg-robbing Phenomena in the Cyanidation of Sulphide Gold Ores”, Hydrometallurgy, Vol. 58, pp. 61-80.

Schmitz, P.A., Duyvesteyn, S., Johnson, W.P., Enloe, L., McMullen, J., (2001), “Adsorption of aurocyanide complexes onto carbonaceous matter from preg-robbing Goldstrike ore”, Hydrometallurgy 61, 121–135.

Stenebraten, J. F., Johnson, W. P., McMullen, J., (2000), “Characterization of Goldstrike Ore”, Carbonaceous Material Part 2, Minerals and Metallurgical Processing 17, pp. 7-15.

Tan, H., Feng, D. and Van Deventer, J. S. J. (2003), “Effect of carbonaceous coatings on preg-robbing of chalcopyrite”, Proceedings Hydrometallurgy 2003 – Fifth International Conference, Young, C.A., Alfantazi, A.M., Anderson, C.G., Dreisinger, D.B., Harris, B. and James, A. (Eds), Pennsylvania, U.S.A, pp. 35-48.

Thompson, L.C., and MacCulloch, I.R. (2004), “Biological Processes for Gold Recovery”, Proceedings of Bac-Min Conference, AUSIMM, Victoria, Australia.

Published
2018-06-28
Section
Minerals Eng. Articles