This technology was initially developed for the industrial water treatment industry but will find application in the metallurgical industry in any application that recovers metals from clear liquid in a fixed bed configuration. The development of shallow shell resins containing functional groups aimed at specific processes, apart from water treatment, are at an advanced stage.
Ion exchange resins are expected to play an ever-increasing role in improving recoveries and reducing costs and environmental risks for gold mining operations. Gold-selective resins have potentially higher gold loadings and improved selectivity than activated carbon, thereby ensuring higher-purity bullion. Probably the biggest advantage of resins over carbon is their reduced energy requirement. Activated carbon is eluted at elevated temperatures of 110-130 °C, while resins are eluted at 55-60 °C. In addition, carbon requires thermal regeneration at 700-800 °C, while resins require only chemical regeneration. This is particularly important for mines in remote locations. Reliable and cheap power is often not readily available and the mines are reliant on diesel that has to be trucked in, adding cost and logistical problems.
Medium-base resins provide a further health & safety advantage, since these resins are eluted under alkaline conditions, thereby eliminating the risk of toxic hydrogen cyanide evolution.
A recent development in the gold-recovery flowsheet is the use of thiosulphate as lixiviant as alternative to cyanide. Some ore-bodies are considered double-refractory, where the gold is occluded by sulfide-minerals and the ore contains native carbon that acts as a preg-robber. In such cases, thiosulphate provides the only viable option. Thiosulphate is also considered as less environmentally hazardous than cyanide. However, activated carbon cannot be used as adsorbent, since it has no affinity for the gold thiosulphate complex. Strong base ion exchange resins are used as adsorbent instead.
Adams, M., Lawrence, R., Bratty, M. (2008). Biogenic sulfide for cyanide recycle and copper recovery in gold-copper ore processing. Minerals Engineering 21 pp. 509-517. Elsevier Ltd.
Bolinsky, L., Shirley, J. (1996). Russian resin-in-pulp technology, current status and recent developments. Randol Gold Forum '96, pp 419-423. Golden, CO: Randol International.
Boodoo, F., Rosie, J. (2010). Ion exchange synergy with other water treatment technologies: The way of the future. Caloundra, Australia: Australian Power Institute.
Breuer, P., Dai, X., Zhang, H., Hewitt, D. (2012). The increased activity in the development of thiosulphate based processes for gold recovery. In ALTA 2012 Gold Conference. Melbourne, Australia: ALTA Metallurgical Services.
Choi, Y. (2013). Thiosulphate processing: from lab curiosity to commercial application. In ALTA 2013 Gold Conference. Melbourne, Australia: ALTA Metallurgical Services.
Dai, X., Simons, A., Breuer, P. (2011). A review of copper cyanide recovery technologies for the cyanidation of copper containing gold ores. Minerals Engineering 25, pp 1-13. Elsevier Ltd.
Fleming, C.A., McMullen, J., Thomas, K.G., Wells, J.A. (2003). Recent advances in the development of an alternative to the cyanidation process: thiosulphate leaching and resin in pulp. Englewood, CO: Society for Mining, Metallurgy, and Explorations, Inc.
Green, B.R., Kotze, M.H., Wyethe, J.P. (2002). Developments in Ion Exchange: The Mintek Perspective. JOM, Volume 54, Issue 10, pp37-43. Warrendale, PA: The Minerals, Metals and Materials Society.
Kotze, M. (2010). Gold Ion Exchange. In ALTA 2010 Gold Conference. Melbourne, Australia: ALTA Metallurgical Services.
Kotze, M., Green, B., Mackenzie, M., Virnig, M. (2005). Resin-in-pulp and resin-in-solution. In Volume 15: Advances in Gold Ore Processing. Editor: M. Adams, Elsevier Science.
Lewis, G.V. (2000). The Penjom Process: An Innovative Approach to Extracting Gold from Carbonaceous Ores. In Gold Processing in the 21st Century: An International Forum. Perth, Australia: A.J. Parker Cooperative Research Centre for Hydrometallurgy.
Marston, C.R., Gisch, D.J. (2010). New Selective Strong Base Anion Exchange Resins with promise for Commercial Gold Cyanidation. In ALTA 2010 Gold Conference. Melbourne, Australia: ALTA Metallurgical Services.
Mintek-designed resin for Azerbaijan gold project. In Mintek 75 Bulletin, Issue No. 148, September 2009.
Petropavlovsk website. www. petropavlovs k.net/en/pioneer /pioneer-technology.html.
Van Deventer, J., Wyethe, J.P., Kotze, M.H, Shannon, J. (1999). Comparison of resin-in-solution and carbon-in-solution for the recovery of gold from clarified solutions. In Extraction Metallurgy 1999. Johannesburg, South Africa: South African Institute of Mining and Metallurgy.
Van Deventer, J., Kotze, M., Yahorava, V. (2012). Gold recovery from copper-rich ores employing the Purolite S992* [currently Purogold MTA9920] gold-selective ion exchange resin. In ALTA 2012 Gold Conference. Melbourne, Australia: ALTA Metallurgical Services.
* Since the publication of this white paper, this product name has changed from S992 to Purogold MTA9920.