Gold extraction using novel ionic thiourea derivatives
Megan L. Himmelman A , Amir Joorab-Doozha A , Christa L. Brosseau A and Robert D. Singer
A *
A Department of Chemistry, Saint Mary’s University, Halifax, NS B3H 3C3, Canada.
Australian Journal of Chemistry 76(1) 37-43 https://doi.org/10.1071/CH22182
Submitted: 19 August 2022 Accepted: 26 September 2022 Published: 23 November 2022
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing.
Abstract
Cyanidation has been used worldwide for over a century as the primary method for gold extraction from ore. Unfortunately, accidents have occurred that released toxic cyanide and resulted in devastation of the environment and surrounding communities. For this reason, alternatives to cyanidation have been of great interest but have yet to be implemented owing to the high costs of materials and necessary changes to infrastructure, which make these alternatives economically unfeasible. Reported herein is the use of novel ionic thiourea derivatives for the extraction of gold without the use of cyanide. A series of six pyrrolidinium and imidazolium salts have been functionalized with a thiourea group and either the anion hexafluorophosphate ([PF6]−) or dodecyl sulfate ([DS]−). Gold(iii) extraction up to 90% was achieved from an aqueous solution with a methyl imidazolium-tagged [DS] salt. Extraction experiments using gold(i) showed a decrease in extraction efficiency, suggesting the oxidation state of the gold is important for complex formation. The extraction selectivity for gold(iii) and silver(i) over copper(ii), iron(ii) and zinc(ii) was demonstrated for all ionic thiourea derivatives.
Keywords: cyanidation, extraction, gold, gold extraction, green chemistry, ionic liquid, selective, thiourea.
References
[1] Gail E, Gos S, Kulzer R, Lorösch J, Rubo A, Sauer M, Kellens R, Reddy J, Steier N, Hasenpusch W. Cyano Compounds, Inorganic. Ullmann’s Encyclopedia of Industrial Chemistry. (Ed C. Ley) Wiley; 2012.[2] C Anning, J Wang, P Chen, I Batmunkh, X Lyu, Determination and detoxification of cyanide in gold mine tailings: A review. Waste Manag Res 2019, 37, 1117.
| Determination and detoxification of cyanide in gold mine tailings: A review.Crossref | GoogleScholarGoogle Scholar |
[3] R Ahtiainen, M Lundström, Cyanide-free gold leaching in exceptionally mild chloride solutions. J Clean Prod 2019, 234, 9.
| Cyanide-free gold leaching in exceptionally mild chloride solutions.Crossref | GoogleScholarGoogle Scholar |
[4] Clayden J, Greeves N, Warren S, Wothers P. Acidity, basicity, and pKa. In ‘Organic Chemistry’. pp. 184–185. (Eds J Clayden, N Greeves, S Warren) New York: Oxford University Press; 2001.
[5] Wikipedia.org. List of Gold Mining Disasters. 2020. Available at https://en.wikipedia.org/wiki/List_of_gold_mining_disasters [accessed September 2019].
[6] Nicol MJ, Fleming CA, Paul RL. The chemistry of the extraction of gold. In ‘The Extractive Metallurgy of Gold in South Africa’. pp. 831–860. (Ed GG Stanley) Council for Mineral Technology (Mintek). 2010
[7] The Mining Association of Canada. Mining Facts. 2021. Available at https://mining.ca/resources/mining-facts/ [accessed September 2019].
[8] S Örgül, Ü Atalay, Reaction chemistry of gold leaching in thiourea solution for a Turkish gold ore. Hydrometallurgy 2002, 67, 71.
| Reaction chemistry of gold leaching in thiourea solution for a Turkish gold ore.Crossref | GoogleScholarGoogle Scholar |
[9] Thiourea. SDS No. 62-56-6. Oakville, ON: Sigma-Aldrich. 6 June 2021. https://www.sigmaaldrich.com/CA/en/sds/sial/t8656 [accessed 28 August 2021].
[10] G Hilson, AJ Monhemius, Alternatives to cyanide in the gold mining industry: what prospects for the future? J Clean Prod 2006, 14, 1158.
| Alternatives to cyanide in the gold mining industry: what prospects for the future?Crossref | GoogleScholarGoogle Scholar |
[11] D Chaturvedi, Recent developments on task-specific ionic liquids. Curr Org Chem 2011, 15, 1236.
| Recent developments on task-specific ionic liquids.Crossref | GoogleScholarGoogle Scholar |
[12] W Gui, Y Shi, J Wei, Z Zhang, P Li, X Xu, Y Cui, Y Yang, Synthesis of N-(3-aminopropyl)imidazole-based poly(ionic liquid) as an adsorbent for the selective recovery of Au(III) ions from aqueous solutions. New J Chem 2020, 44, 20387.
| Synthesis of N-(3-aminopropyl)imidazole-based poly(ionic liquid) as an adsorbent for the selective recovery of Au(III) ions from aqueous solutions.Crossref | GoogleScholarGoogle Scholar |
[13] AE Visser, RP Swatloski, WM Reichert, R Mayton, S Sheff, A Wierzbicki, JH Davis, RD Rogers, Task-specific ionic liquids incorporating novel cations for the coordination and extraction of Hg2+ and Cd2+: Synthesis, characterization, and extraction studies. Environ Sci Technol 2002, 36, 2523.
| Task-specific ionic liquids incorporating novel cations for the coordination and extraction of Hg2+ and Cd2+: Synthesis, characterization, and extraction studies.Crossref | GoogleScholarGoogle Scholar |
[14] JR Harjani, T Friščić, LR MacGillivray, RD Singer, Removal of metal ions from aqueous solutions using chelating task-specific ionic liquids. Dalton Trans 2008, 34, 4595.
| Removal of metal ions from aqueous solutions using chelating task-specific ionic liquids.Crossref | GoogleScholarGoogle Scholar |
[15] N Papaiconomou, G Vite, N Goujon, J-M Lévêque, I Billard, Efficient removal of gold complexes from water by precipitation or liquid–liquid extraction using ionic liquids. Green Chem 2012, 14, 2050.
| Efficient removal of gold complexes from water by precipitation or liquid–liquid extraction using ionic liquids.Crossref | GoogleScholarGoogle Scholar |
[16] S Boudesocque, A Mohamadou, L Dupont, Efficient extraction of gold from water by liquid–liquid extraction or precipitation using hydrophobic ionic liquids. New J Chem 2014, 38, 5573.
| Efficient extraction of gold from water by liquid–liquid extraction or precipitation using hydrophobic ionic liquids.Crossref | GoogleScholarGoogle Scholar |
[17] M Wang, Q Wang, J Wang, R Liu, G Zhang, Y Yang, Homogeneous liquid–liquid extraction of Au(III) from acidic medium by ionic liquid thermomorphic systems. ACS Sustainable Chem Eng 2021, 9, 4894.
| Homogeneous liquid–liquid extraction of Au(III) from acidic medium by ionic liquid thermomorphic systems.Crossref | GoogleScholarGoogle Scholar |
[18] Campbell JW. A mechanochemical approach for organocatalysis and improved synthesis of gemini surfactants. Bachelor of Science with Honours in Chemistry, Saint Mary’s University, Halifax, NS; 2020.
