Gold and Modern Hydrometallurgy: About fourteen decades of partnership

Francisco José Alguacil; Luis Javier  Lozano-Blanco

doi:10.3989/revmetalm.e300.1760

Authors

Francisco José Alguacil Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC) https://orcid.org/0000-0002-0247-3384
Luis Javier Lozano-Blanco Department of Chemical and Environmental Engineering, Universidad Politécnica de Cartagena https://orcid.org/0000-0001-8146-5827

DOI:

https://doi.org/10.3989/revmetalm.e300.1760

Keywords:

Gold, Hydrometallurgy, Leaching, Separation technologies, Recovery, Recycling

Abstract

This year marks the 138th anniversary of the beginning of modern Hydrometallurgy. This milestone began in 1887 with the publication of the cyanidation patent by McArthur and the Forrester brothers, which represented a decisive step forward in the recovery of gold from gold-bearing ores. New technologies, such as gold adsorption on activated carbon, have made cyanidation the established basis of gold Hydrometallurgy. On the other hand, in the 21st century, the concept of urban mining and recycling has made the recovery of gold from waste materials a necessity. This work combines the basic concepts of gold Hydrometallurgy with new developments in this technology when applied to both primary and secondary materials.

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Author Biography

Francisco José Alguacil, Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC)

Consejo de Redaccion

References

Abbott, A.P., Capper, G., Davies, D.L., Rasheed, R.K., Tambyrajah, V. (2003). Novel solvent properties of choline chloride/urea mixtures. Chem. Commun. 1, 70-71.

Abbott, A.P. (2022). Deep eutectic solvents and their application in electrochemistry. Curr. Opin. Green Sustain. Chem. 36, 100649.

Adams, M.D. (2001). A methodology for determining the deportment of cyanide losses in gold plants. Miner. Eng. 14, 383-390.

Aguayo, S., Valenzuela, J.L., Parga, J.R., Lewis, R.G., Cruz, M. (2007). Continuous laboratory gold solvent extraction from cyanide solutions using LIX 79 reagent. Chem. Eng. Technol. 30, 1532-1536.

Akcil, A. (2010). A new global approach of cyanide management: international cyanide management code for the manufacture, transport, and use of cyanide in the production of gold. Miner. Proc. Extract. Metal. Rev. 31, 135-149.

Alguacil, F.J., Hernández, A., Luis, A. (1989). Recovery of gold and silver from Spanish ores by pressure leaching. In: 2nd International Conference on Separation Science and Technology, Baird, M.H.I., S.Vijayan, S. (Eds), Canadian Society for Chemical Engineering, Ottawa, Canada.

Alguacil, F.J. (1998). Recovery of tetrachloroaurate through ion exchange with Dowex 11 resin. Rev. Metal. 34, 376-380.

Alguacil, F.J., Adeva, P., Alonso, M. (2005). Processing of residual gold(III) solutions via ion exchange. Gold Bull. 38, 9–13.

Alguacil, F.J. (2017). Non-dispersive extraction of gold(III) with ionic liquid Cyphos IL101. Sep. Purif. Technol. 179, 72-76.

Alguacil, F.J. (2018). Adsorption of gold(I) and gold(III) using multiwalled carbon nanotubes. Appl. Sci. 8, 2264.

Alguacil, F.J. (2019). Mechanistic investigation of facilitated transport of gold(III) from HCl media using ionic liquid Cyphos IL102 as carrier across a supported liquid membrane. Gold Bull. 52, 145-151

Alguacil, F.J. (2026). Unpublished results.

Aljarrah, M.T., Alboull, A.M., Alharahsheh, M.S., Azad Ashraf, A., Khandakar, A. (2022). Parametric study of gold nanoparticles synthesis under micro-continuous flow conditions. Molecules 27, 8651.

Anastas, P.T., Warner J.C. (1998). Green Chemistry: Theory and Practice. Oxford University Press, New York, USA.

Andries, H., De Rop, M., Breugelmans, T., Hereijgers, J. (2024). Towards continuous selective electrowinning of gold from wasteprinted circuit boards in acidic chloride medium: a parametric study. J. Appl. Electrochem. 54, 2791-2808.

Arima, H., Fujita, T., Yen, W.T. (2003). Thermodynamic evaluation of gold oxidation and reduction mechanisms in ammonium thiosulfate solution. Miner. Metal. Proc. 20, 81-92.

Aydın, Ş B., Gül, A. (2021). Environmentally friendly process instead of cyanide leaching on recycling of gold and silver from jewellery scraps and wastes. Waste Manag. Res. 39, 233–241.

Azizitorghabeh, A., Wang, J., Ramsay, J.A., Ghahreman, A. (2021). A review of thiocyanate gold leaching – chemistry, thermodynamics, kinetics and processing. Miner. Eng. 60, 106689.

Baghalha, M. (2007). Leaching of an oxide gold ore with chloride/hypochlorite solutions. Int. J. Miner. Proc. 82, 178-186.

Bae, M., Kim, H., Kim, S., Lee, H. (2022). Electrowinning of gold from a dilute solution using hydrocyclone-type cell. Geosystem Eng. 25, 175-184.

Bai Y., Ge, H., Li, Q., Xie, F. Wang, W. (2025). Ultrasound-assisted activated carbon adsorption Au(CN)2−. Materials 18, 1526.

Barbouchi, A., Louarrata, M., Mikalia, M., Barfoud, L., El Alaoui-Chriﬁa, M.A., Faqira, H., Benzakoura, I., Idouhlib, R., Khadirib, M., Benzakour, J. (2025). Advancements in improving gold recovery from refractory gold ores/concentrates: a review. Can. Metall. Q. 64, 2370-2387.

Bediako, J.K., Affrifah, N.S., Yun, Y.-S., Repo, E. (2025). Experimental optimization of aurocyanide adsorption onto biomass activated carbon and re-examination of the adsorption mechanisms. Miner. Eng. 227, 109293.

Behnamfard, A., Salarirad, M.M., Veglio, F. (2013). Process development for recovery of copper and precious metals from waste printed circuit boards with emphasize on palladium and gold leaching and precipitation. Waste Manage. 33, 2354-2363.

Berezowsky, R.M.G.S., Collins, M.J., Kerfoot, D.G.E., Torres, M.S. (1991). The commercial status of pressure leaching technology. JOM 43, 9-15.

Bhakta, P. (2003). In Hydrometallurgy (2003). Proceedings 5th International Symposium Honoring Prof. I.M.Ritchie. Eds. Young, C.A., Alfantazi, A., Anderson, C. James, A., Dreisinger, D., Harris, B. 259-268. Trans Metallurgical Society. Warrendale. PA. USA.

Bullion by Post. (2026). www.bullionbypost.eu

Burat, F., Demirağ, A., Safak, M.C. (2020). Recovery of noble metals from floor sweeping jewelry waste by flotation-cyanide leaching. J. Mater. Cycles Waste Manag. 22, 907–915.

Buronov, A.B., Yayabu, B.K., Godirilwe, L.L., Altansukh, B., Jeon, S., Haga, K., Shibayama, A. (2025). Copper–ammonia–thiosulfate leaching of high-sulfide concentrates: process optimization and additive effects on gold extraction. Metals 15, 572.

Bystrzanowska, M., Tobiszewski, M. (2021). Assessment and design of greener deep eutectic solvents-a multicriteria decision analysis. J. Mol. Liq. 321, 114878.

Cao, J., Su, E. (2021). Hydrophobic deep eutectic solvents: the new generation of green solvents for diversified and colorful applications in green chemistry. J. Clean. Prod. 314, 127965.

Camelino, S., Rao, J., López Padilla, R., Lucci, R. (2015). Initial studies about gold leaching from printed circuit boards (PCB’s) of waste cell phones. Procedia Mater. Sci. 9, 105-112.

Cespi, D., Ciacci, L., Chiarini, A., Trova, E., Acciai, C., Ciabatti, I., Tirinnanzi, M., Passarini, F. (2025). LCA of precious metals recovery: Modelling the secondary supply of gold, silver, platinum, palladium and rhodium from an integrated refining plant. Clean. Environ. Syst. 19, 100310.

Cheng, M., Yan, X., Liu, W., Li, R., Song, G. (2024). Cyanide-functionalized ionic liquid-modified polymer as an adsorbent for highly efficient and selective recovery of Au(III). J. Environ. Chem. Eng. 12, 114238.

Chen, Y., Zhu, G., Chen, W., Lei, F., Xiang, H., Yang, X., Wang, S. (2025). Amino acid ionic liquid two-phase system: construction and its application for green gold recovery from e-waste thiosulfate leachate. Langmuir 41, 18834-18847.

Cifuentes, G., Vargas, C., Simpson, J., Esteban, R. (2000). Electrowinning of gold from cyanide solutions. In: Proceedings of the XXI International Mineral Processing Congress. Volume A. Masacci, P. (Ed.). Elsevier, Amsterdam, The Netherlands.

Cox, M. (1992). Solvent Extraction in Hydrometallurgy. In: Principles and Practices of Solvent Extraction. Rydberg, J., Musikas, C., Choppin, G.R. (Eds.), Marcel Dekker, New York, USA

De Almeida Lemos, F., Nascimiento, M., Rodriguez Moreira Jr., G., Resende de Andrade, V., Cezanne Pinto, P., Guedes Salles, A.J. (2025). Recovery of gold from refractory ore employing pressure oxidation. REM, Int. Eng. J., Ouro Preto 78, e23 0116.

Diaz, M.A., Kelsall, G.H., Welham, N.J. (1993). Electrowinning coupled to gold leaching by electrogenerated chlorine: I. Au(III)Au(I)/Au kinetics in aqueous Cl2/Cl− electrolytes. J. Electroanal. Chem. 361, 25-38.

Dietz, Jr., G., Skomoroski, R.M. (1978). Aluminium containing precipitating agent for precious metals and methods for its use. US Patent 4092154

Ding, Y., Zhang, S., Liu, B., Zheng, H., Chang, C., Ekberg. C. (2019). Recovery of precious metals from electronic waste and spent catalysts: a review. Resour. Conserv. Recycl. 141, 284-298.

Dong, Z., Jiang T., Xu, B., Yang, Y., Li, Q. (2019). An eco-friendly and efficient process of low potential thiosulfate leaching-resin adsorption recovery for extracting gold from a roasted gold concentrate. J. Clean. Prod. 229, 387-398.

Dunn, J.G., Chamberlain, A.C. (1997). The recovery of gold from refractory arsenopyrite concentrates by pyrolysis-oxidation. Miner. Eng. 10, 919-928.

El Achkar, T., Greige-Gerges, H., Fourmentin, S. (2021). Basics and properties of deep eutectic solvents: a review. Environ. Chem. Lett. 19, 3397-3408.

Ellis, S. (2005). Treatment of gold-telluride ores. In: Developments in Mineral Processing, Vol. 15 (Advances in Gold Ore Processing), Adams, M.D., Wills, B.S. (Eds.). Elsevier, Amsterdam. The Netherlands.

Elomaa, H., Seisko, S., Junnila, T., Sirviö, T., Wilson, B.P., Aromaa, J., Lundström, M. (2017). The effect of the redox potential of aqua regia and temperature on the Au, Cu, and Fe dissolution from WPCBs. Recycling 2, 14.

Faghirinejad, F., Barani, K., Ghaedrahmati, R. (2025). Adsorption-desorption of gold onto activated carbon from cyanide-glycine leach solution of complex gold ore. J. Chem. Technol. Metal. 60, 427-434.

Fan, Y., Zhou, Q., Zhang, S., Nie, Y. (2024). Ionic liquids functionalized chitosan: An effective, rapid and green adsorbent for gold recovery. Int. J. Biol. Macromol. 274, Part 2, 133481.

Fernández-Lera, A., Casal, M.D., Judalet, Q., Díez, N., Valdés-Solís, T., Sevilla. M. (2025). From green to black gold: highly microporous carbons from pistachio shells by a controlled physical activation process. ChemSusChem 18, e202401288.

Freitas, J., Horta, D. (2023). Impacts of cyanide in gold mining and cyanide removal methodologies in liquid waste from gold processing. Rev. Metal. 59, e247.

Fu, J., Nakamura, S., Akiba, K. (1994). Liquid-membrane transport of gold by a trioctylamine mobile carrier. Anal. Sci. 10, 935-938.

Galvan Lira, J.M., Carrillo Pedroza, F.R., Soria Aguilar, M.J., Aguilera González, E.N. (2025). Gold electrowinning from cyanide solutions using modified electrolytic cells. MRS Adv. 10, 884-889.

Geng, Y., Xiang, Z., Lv, C., Wang, N., Wang, Y., Yang, Y. (2019). Recovery of gold from hydrochloric medium by deep eutectic solvents based on quaternary ammonium salts. Hydrometallurgy 188, 264-271.

Ghazitabar, A., Naderi, M., Fatmehsari Haghshenas, D., Alijani Ashna, D. (2020). Graphene aerogel/cellulose fibers/magnetite nanoparticles (GCM) composite as an effective Au adsorbent from cyanide solution with favorable electrochemical property. J. Mol. Liq. 314 (2020) 113792.

Goc, K., Kluczka, J., Benke, G., Malarz, J., Pianowska, K., Leszczyńska-Sejda, K. (2024). Precipitation of precious metals concentrates from post-elution solutions from ion-exchange processes. Minerals 14, 625.

Godigamuwa, K., Okibe, N. (2023). Gold leaching from printed circuit boards using a novel synergistic effect of glycine and thiosulfate. Minerals 13, 1270.

Gönen, N., Körpe, E., Yıldırım, M., Selengil, U. (2007). Leaching and CIL processes in gold recovery from refractory ore with thiourea solutions. Miner. Eng. 20, 559-565.

Graham, J., Fletcher, A., Walker, G., Aylmore, M. (1992). A pyrolysis approach to refractory gold processing. In: Intenational Conference of Extractive Metallurgy of Gold and Base Metals. Misra, V.N., Halbe, D., Spottiswood, D.J. (Eds.), The Australasian Institute of Mining and Metallurgy, Cartlon, Victoria, Australia.

Greaves, J.N., Palmer, G.R., White, W.W. (1990). The recovery of gold from refractory ores by the use of carbon-in-chlorine leaching. JOM 42, 12-14.

Ha, V.H., Lee, J.C., Jeong, J.; Hai, H.T., Jha, M.K. (2010). Thiosulfate leaching of gold from waste mobile phones. J. Hazard. Mater. 178 1115-1119.

Habashi, F. (1987). One hundred years of cyanidation. CIM Bull. 80, 108-114.

Habashi, F. (1966). The theory of cyanidation. Transactions of the Mineralogical Society of AIME 235, 236-239.

Hammami, I., Alabdallah, N.M., Al Jomaa, A., Kamoun, M. (2021). Gold nanoparticles: synthesis properties and applications. J. King Saud Univ.-Sci. 33, 101560.

He, H., Yang, X., Li, S., Xu, Y., Ye, S., Xiong, M., Yang, N., Feng, C., Zhang, Y., Nie, Z. (2025). Quaternary amine-functionalized electrospun nanofibers for selective gold capture: Experimental and DFT calculation study. Sep. Purif. Technol. 376, Part 1, 133945.

Heath, A.R., Rumball, J.A. (1998). Optimizing cyanide:oxygen rations in gold CIP(CIL circuits. Miner. Eng. 11, 999-1010.

Healy, T.V., Mckay, D.H.A.C. (1956). The extraction of nitrates by try-n-butyl phosphate (TBP). Part 2.-The nature of the TBP phase. Trans. Far. Soc. 52, 633-642.

Iglesias, N., Carranza, F. (1994). Refractory gold-bearing ores: a review of treatment methods and recent advances in biotechnological techniques. Hydrometallurgy 34, 383-395.

Ilkhani, Z., Aiouache, F. (2025). Bioleaching of gold from printed circuit boards: potential sustainability of thiosulphate. Recycling 10, 87.

Ippolito, N.M., Medici, F., Pietrelli, L., Piga, L. (2021a). Effect of acid leaching pre-treatment on gold extraction from printed circuit boards of spent mobile phones. Materials 14, 362.

Ippolito, N.M., Birloaga, I., Ferella, F., Centofanti, M., Vegliò, F. (2021b). Preliminary study on gold recovery from high grade e-waste by thiourea leaching and electrowinning. Minerals 11, 235.

Ippolito, N.M., Passadoro, M., Ferella, F., Pellei, G., Vegliò, F. (2023). Recovery of metals from printed circuit boards by gold-REC 1 hydrometallurgical process. Sustainability 15, 7348.

Jeong, G.H., Lee, Y.W., Kim, M., Han, S.W. (2009). High-yield synthesis of multi-branched gold nanoparticles and their surface-enhanced Raman scattering properties. J. Colloid Interface Sci. 329, 97-102.

Jermakowicz-Bartkowiak, D., Kolarz, B.N., Tylus, W. (2003). Sorption of aurocyanide and tetrachloroaurate onto resin with guanidine ligand - an XPS approach. Polymer 44, 5797-5802.

Ji, L., Song, Y., Taghvaie Nakhjiri, A. (2024). Different approaches for sustainable recovery of precious metals from electronic wastes: techno-economic evaluation and future perspectives. Ain Shams Eng. J. 15, 103005.

Jiga, A.P., Pasithbhattarabhorn, J., Juntarasakul, O., Pimolrat, J., Soonthornwiphat, N., Phengsaaret. T. (2022). Gold recovery from the residue of jewelry waste recycling: pre-treatment using shaking table separation and flotation. IOP Conf. Ser.: Earth Environ. Sci. 1071, 012024.

Jumadilov, T., Suleimenova, M., Gražulevičius, J.V. (2025). Selective sorption of gold ions from iron-rich solutions using a dual-phase interpolymer system. Eng. Sci. 35, 1482.

Khuduwe, M.J., Shemi, A., Ndlovu, S. (2024). Extraction of gold from tailings using ethaline deep eutectic solvent. Minerals 14, 1239.

Kim, B.-K., Lee, E.J., Kang, Y., Lee, J,-J. (2018). Application of ionic liquids for metal.dissolution and extraction. J. Ind. Eng. Chem. 61, 388–397.

Kirk, D.W., Foulkes, F.R. (1984). A potentiodynamic study of metals affecting precious metal recovery from alkaline cyanide solutions J. Electrochem. Soc. 131, 760-769.

Kordosky, G.A., Sierakoski, J.M., Virnig, M.J., Mattison, P.L. (1992). Gold solvent extraction from typical cyanide leach solutions. Hydrometallurgy 30, 291-305.

Kumar, A., Haddad, R., Benzal, G., Ninou, R., Sastre, A.M. (2000). Use of modified membrane carrier system for recovery of gold cyanide from alkaline cyanide media using hollow fiber supported liquid membranes: feasibility studies and mass transfer modeling. J. Membr. Sci. 174, 17-30.

Lee, C.K., Rhee, K.-I., Sohn, H.-J. (1997). Recovery of gold from electronic scrap by hydrometallurgical processes. J. Korean Inst. of Resour. Recycl. 6, 36-40

Li, J., Miller, J.D. (2006). A review of gold leaching in acid thiourea solution. Miner. Process. Extr. Metall. 27 177-214.

Li, J., Xu, X., Liu, W. (2012). Thiourea leaching gold and silver from the printed circuit boards of waste mobile pones. Waste Manag. 32, 1209-1212.

Li, K., Li, Q., Zhang, Y., Liu, X., Yang, Y., Jiang, T. (2023a). Improved thiourea leaching of gold from a gold ore using additives. Hydrometallurgy 222, 106204.

Li, F., Cai, K., Huang, Q., Zhong, M., Wang, L., Song, Q., Yuan, W. (2023b). Recovery of Au and Cu from waste memory modules by electrolysis with hydrochloric acid-hydrogen peroxide system. Sep. Purif. Technol. 308, 122872.

Li, W., Liu, B., Wu, J., Liu, W., Jiao, F., Qin, W. (2024). Gold recovery from roasted refractory gold concentrate through cyclic extraction using MnO2-assisted thiocyanate leaching and cementation with zinc powder. Hydrometallurgy 228, 106359.

Li, Q., Zhu, Y., Zhang, Y., Liu, X., Ma, Y., Yang, Y., Jiang, T. (2025a). Highly selective and efficient gold recovery from ferricyanide-thiourea synergistically catalyzed thiosulfate leachate by diphenylphosphine extraction and acidic thiourea back-extraction. Sep. Purif. Technol. 370, 133311.

Li, X., Chen, S., Hu, X., Zi, F. (2025b). Selective and fast recovery of Au(I) from thiosulfate gold leaching solution: the role of aromatic adsorbents. J. Mol. Struct. 1347, 143362.

Li, Z., Chen, F., He, X., Li, X., Liu, X., Feng, Z., Chen, T., Yuan, J., Zhang, W., Liao, Y. (2025c). Nanoconfined polycarbene@covalent organic frameworks for efficient gold trapping from electronic waste. Adv. Funct. Mater. 35, 2507398.

Liang, Y., Lian, W., Liu, C., Chen, P., Ge, J., Zhan., Li, J., Song, S., Jia, F. (2025). Bipolar reduction for efficient gold extraction from dilute Au(S2O3)23− solution at low cell voltage. Chem. Eng. J. 525, 170366.

Lin, C., Tao, K., Hua, D., Ma, Z., Zhou, S. (2013). Size effect of gold nanoparticles in catalytic reduction of p-nitrophenol with NaBH4. Molecules 18, 12609-12620.

Lin, X., Tran, D.T., Song, M.-H., Yun, Y.-S. (2022). Development of quaternized polyethylenimine-cellulose fibers for fast recovery of Au(CN)2- in alkaline wastewater: Kinetics, isotherm, and thermodynamic study. J. Hazard. Mater. 422, 126940.

Lin, X., Song, M.-H., Lei, L., Tran, D.T., Shu, Y., Lim, C.-R., Wu, X., Mao, J., Yun, Y.-S. (2025). Rapid and efficient recovery of Au(I) from cyanide gold leachate via quaternary ammonium-functionalized chitosan fibers: Insights into synthesis mechanism and adsorption behavior. Sep. Purif. Technol. 362, Part 2, 131830.

Lindström, E.B., Gunneriusson, E., Tuovinen, O.H. (1992). Bacterial oxidation of refractory sulfide ores for gold recovery. Crit. Rev. Biotechnol. 12, 133-155.

Liu, Z., Kou, J., Xing, Y., Sun, C., Zhang, Y. (2023a). Environmentally friendly ionic liquid medium based on dicyanamide anion for leaching gold from e-waste CPUs by iodination. J. Chem. Technol. Biotechnol. 98, 86–97.

Liu, X., Wang, Y., Liu, R. Lv, P. Xue, W.Guo, J. Wei, H., Yang, Y. (2023b). Selective and efficient gold extraction from e-waste by pyrrolidinium-based ionic liquids with various N-substituents. ACS Sust. Chem. Eng. 11, 638-648.

Liu, G., Wu, Y., Li, B., Yuan, H., Gu, J., Pan, D. (2024a). A combined and sustainable approach and a novel mechanism for recovering Bi, Au and Ag from high-chloride leachate of waste printed circuit board smelting ash. J. Hazard. Mater. 465, 133349.

Liu, R., Li, J., Liu, X., Yin, X., Yang, Y. (2024b). Dibutylamide hydrophobic deep eutectic solvent used for selective extraction of Au(III) from hydrochloric acid medium. Hydrometallurgy 226, 106312.

London Metal Exchange. (2026). www.lme.com

Lorenzen, L., van Deventer, J.S.J. (1992). Electrochemical interactions between gold and its associated minerals during cyanidation. Hydrometallurgy 30, 177-204.

Luo, C., Zhu, E., Zhao, S., Wang, S., Xia, H., Li, J., Dai, L., Zhang, G., Fu, L., Zuo, Y., Zhang, L. (2025). Ultrafast regeneration of spent activated carbon and sustainable application. J. Environ. Chem. Eng. 13, 115720.

Luty-Błocho, M., Fitzner, K., Hessel, V., Löb, P., Maskos, M., Metzke, D., Pacławski, K., Wojnicki, M. (2011). Synthesis of gold nanoparticles in an interdigital micromixer using ascorbic acid and sodium borohydride as reducers. Chem. Eng. J. 171, 279-290.

Mainz, V.V. (2015). The Metals of Antiquity and Their Alloys. In: Chemical technology in Antiquity. Rasmussen, S.C. (Ed.). ACS Symposium Series, Vol. 1211.

Marsden, J.O., House, C.I. (2006). The Chemistry of Gold Extraction. SME. Littleton, USA

Martinez, S., Sastre, A.M., Alguacil, F.J. (1997). Gold extraction equilibrium in the system Cyanex 921-HCl-Au(III). Hydrometallurgy 46, 205-214.

Maslenitskii, I.N. (1948). Dispersed gold inclusions in iron sulfides. J. Min. Inst. 17, 101-115. https://pmi.spmi.ru/pmi/article/view/14935

Matsumoto, A., Abe, S., Shimizu, N., Osaka, T., Kadowaki, J., Yae, S. (2025). Gold recovery via silicon powder cementation from a thiosulfate leaching solution after gold metal dissolution. Electrochemistry 93, 067002.

Mehedi Hasan Rocky, M., Rahman, I.M.M., Endo, M., Hasegawa, H. (2024). Comprehensive insights into aqua regia-based hybrid methods for efficient recovery of precious metals from secondary raw materials. Chem. Eng. J. 495, 153537.

Michałek, T., Wojtaszek, K., Youssif, M.M., Żabiński, P., Kołczyk-Siedlecka, K., Kowalik, R., Socha, R.P., Hessel, V., Wojnicki, M. (2025). Adsorption of Au(III), Pt(IV), Pd(II), and Rh(III) ions on activated carbon in a batch reactor supported by microwave radiation. Sci. Rep. 15, 5852.

Mohamed, A.H.A., Youpoungam, A.A., Boyraz, T., Alp, İ., Sinon, A. (2025). Characterization and evaluation of glycine and cyanide leaching application on artisanal gold mining tailings. Physicochem. Probl. Miner. Proc. 61, 205177.

Morris, D.F.C., Ali Khan, M. (1968). Application of solvent extraction to the refining of precious metals-III: purification of gold. Talanta 15, 1301-1305.

Msumange, D.A., Yazici, E.Y., Celep, O., Deveci, H., Kritskii, A., Karimov, K. (2023). Recovery of Au and Ag from the roasted calcine of a copper-rich pyritic refractory gold ore using ion exchange resins. Miner. Eng. 195, 108017.

Mubarok, M.Z., Winarko, R., Chaerun, S.K., Rizki, I.N., Ichlas, Z.T. (2017). Improving gold recovery from refractory gold ores through biooxidation using iron-sulfur-oxidizing/sulfur-oxidizing mixotrophic bacteria. Hydrometallurgy 168, 69-75.

Munshi, M.A.M., Chowdhury, E.H., Paniagua-Guerra, L.E., Dionne, J., Giri, A., Ramos-Alvarado, B. (2025). A review of heat transport in solvated gold nanoparticles: molecular dynamics modeling and experimental perspectives. Nanoscale 17, 20803-20830.

Navarro P., Vargas C., Villarroel A., Alguacil F.J. (2002). On the use of ammoniacal/ammonium thiosulphate for gold extraction from a concentrate. Hydrometallurgy 65, 37-42.

Navarro, P., Vargas, C., Alonso, M., Alguacil, F.J. (2006). The adsorption of gold on activated carbon from thiosulfate-ammoniacal solutions. Gold Bull. 39, 93–97.

Nestor, D., Valdivia, U., Chaves, A.P. (2001). Mechanisms of bioleaching of a refractory mineral of gold with Thiobacillus ferrooxidans. Int. J. Miner. Process. 62, 187-198.

Nguyen, T.N.H., Lee, M.S. (2025). Simple process for the recovery of gold metals and palladium(II) compound from aqua regia etching solutions of printed circuit boards by chemical reduction and precipitation. Gold Bull. 58, 1.

Nicol, M.J. (1980). The anodic behavior of gold. Part II. Oxidation in alkaline solutions. Gold Bull. 13, 105-111.

Nicol, M.J. (2023). The dissolution of gold in chloride media under ambient conditions-a re-assessment of mechanisms. Hydrometallurgy 222, 106175.

Nie, W.-Y., Li, L., Li, D.-L., Liu, X. (2014). A new preparation method of gold nanoparticles by intra-reduction of sodium gold(I) sulfite. Chinese Chem. Lett. 25, 380-382.

Niu, H., Yang, H., Tong, L. (2024). Gold recovery from chloride leach solution of TCCA using D301 anion exchange resin and elution with thiourea. Hydrometallurgy 230, 106384.

Ola, P. D., Matsumoto, M. (2023). Extraction of Au(III), Pt(IV), and Pd(II) from aqueous media with deep eutectic solvent dissolved in n-heptane as extractant. Indonesian J. Chem. 23, 1735-1741.

Oliveira, M., Sousa, A., Sá, S., Soares, S., Pereira, A.C., Rocha, A.C., Pais, P., Ferreira, D., Almeida, C., Luís, C., Lima, C., Almeida, F., Gestoso, A., Duarte, M.-C., Barata, P., Martins-Mendes, D., Baylina, P., Pereira, C.F., Fernandes, R. (2024). Harvesting the power of green synthesis: gold nanoparticles tailored for prostate cancer therapy. Int. J. Mol. Sci. 25, 2277.

Oraby, E.A., Eksteen, J.J. (2015). Gold leaching in cyanide-starved copper solutions in the presence of glycine. Hydrometallurgy 156, 81-88.

Oraby, E.A., Eksteen, J.J., Tanda, B.C. (2017). Gold and copper leaching from gold-copper ores and concentrates using a synergistic lixiviant mixture of glycine and cyanide. Hydrometallurgy 169, 339-345.

Pabby, A.K., Wickramasinghe, S.R., Sirkar, K.K., Sastre, A.M. (2020). Hollow fiber membrane contactors: introduction and perspectives. In: Hollow Fiber Membrane Contactors. Pabby, A.K., Wickramasinghe, S.R., Sirkar, K.K., Sastre, A.M. (Eds.), CRC Press, Boca Raton, USA.

Palomar, J., Lemus, J., Navarro, P., Moya, C., Santiago, R., Hospital-Benito, D., Hernandez, E. (2024). Process simulation and optimization on ionic liquids. Chem. Rev. 124, 1649-1737.

Parga, J.R., Valenzuela, J.L., Francisco, C.T. (2007). Pressure cyanide leaching for precious metals recovery. JOM 59, 43–47.

Park, Y.J.; Fray, D.J. (2009). Recovery of high purity precious metals from printed circuit boards. J. Hazard. Mater. 167, 1152–1158.

Paul, R.L., Filmer, A.O., Nicol, M.J. (1983). The recovery of gold from concentrated aurocyanide solutions. In: Proceedings of the 3rd International Symposium on Hydrometallurgy: Hydrometallurgy, Research, Development and Plant Practice. Osseo-Asare, K., Miller, J.D. (Eds.). TMS, Warrendale, USA.

Perpetua Resources (2025). Stibnite Gold Project. Idaho. USA. https://perpetuaresources.com/wp-content/uploads/2021/10/2021_10_15_-ModPRO2_Revision_clean.pdf. (accessed December 2025).

Petter, P.M.H., Veit, H.M., Bernardes, A.M. (2013). Evaluation of gold and silver leaching from printed circuit board of cellphones. Waste Manag. 34, 475-482.

Piervandi, Z. (2023). Pretreatment of refractory gold minerals by ozonation before the cyanidation process: a review. J. Environ. Chem. Eng. 11, 109013.

Potgieter, J.H., Potgieter, S.S., Mbaya, R.K.K., Teodorovic, A. (2004). Small-scale recovery of noble metals from jewellery wastes. J. South African Inst. Mining Metall. 104, 563-571.

Rao, M.D., Meshram, R.B., Singh, K.K., Morrison, C.A., Love, J.B. (2023). Life cycle analysis on sequential recovery of copper and gold from waste printed circuit boards. Waste Manag. 171, 621-627.

Ray, D.A., Baniasadi, M., Graves, J.E., Greenwood, A., Farnaud, S. (2022). Thiourea leaching: an update on a sustainable approach for gold recovery from e-waste. J. Sustain. Metall. 2022, 8, 597–612.

Rezaee, M., Abdollahi, H., Saneie, R., Mohammadzadeh, A., Rezaei, A., Darvanjooghi, M.H.K., Brar, S.K., Magdouli, S. (2022). A cleaner approach for high-efficiency regeneration of base and precious metals from waste printed circuit boards through stepwise oxido-acidic and thiocyanate leaching. Chemosphere 298, 134283.

Ritcey, G.M., Ashbrook, A.W. (1979). Solvent Extraction. Part II. Elsevier, Amsterdam, The Netherlands.

Ritcey, G.M., Ashbrook, A.W. (1984). Solvent Extraction. Part I. Elsevier, Amsterdam, The Netherlands.

Rizki, I.N., Tanaka, Y., Okibe, N. (2019). Thiourea bioleaching for gold recycling from e-waste. Waste Manag. 84, 158-165.

Rodríguez, Y., Blázquez, M. L., Ballester, A., González, F., Muñoz, J. A. (2001). Bioleaching at the beginning of the 21st century. Rev. Metal. 37, 616-627.

Saffaj, S., Mantovani, D., Kolliopoulos, G. (2025). Sustainable leaching of Cu, Ni, and Au from waste printed circuit boards using choline chloride-based deep eutectic solvents. Metals 15, 82.

Sahin, M., Akcil, A., Erust, C., Altynbek, S., Sekhar Gahan, C., Tuncuk, A. (2015). A potential alternative for precious metal recovery from e-waste:iodine leaching. Sep. Sci. Technol. 50, 2587–2595.

Sakai, T., Enomoto, H., Sakai, H.,Abe, M. (2014). Hydrogen-assisted fabrication of spherical gold nanoparticles through sonochemical reduction of tetrachloride gold(III) ions in water. Ultrasonics Sonochem. 21, 946-950.

Samsonov, G.V., Pasechnik, V.A. (1969). Ion exchange and the swelling of ion-exchange resins. Russian Chem. Rev. 38, 547-565.

Sastre, A.M., Madi, A., Cortina, J.L. Alguacil, F.J. (1999). Solvent extraction of gold by LIX 79: experimental equilibrium study. J. Chem. Technol. Biotechnol. 74, 310–314.

Sastre, A.M., Madi, A., Alguacil, F.J. (2000). Facilitated supported liquid-membrane transport of gold(I) using LIX 79 in cumene. J. Membr. Sci. 166, 213-219.

Schalch, E., Nicol, M.J. (1978). A study of certain problems associated with the electrolytic refining of gold. Gold Bull. 11, 117-123.

Schmidt, R., Barbagelata, F., Rivera, H., Valencia, J., Moya, S.A. (1988). Adsorption of gold from acid thiourea solutions on activated carbon. Int. J. Miner. Process. 23, 253-264.

Schwartzberg, A.M., Grant, C.D., Van Buuren, T., Zhang, J.Z. (2007). Reduction of HAuCl4 by Na2S revisited: The case for Au nanoparticle aggregates and against Au2S/Au core/shell particles. J. Phys. Chem. C 111, 8892-8901.

Senayake, G.; Perera, W.N., Nicol, M.J. (2003). In Hydrometallurgy 2003. Proceedings 5th International Symposium Honoring Prof. I.M.Ritchie. Eds. Young, C.A., Alfantazi, A., Anderson, C. James, A., Dreisinger, D., Harris, B. 155-168. Transactions of the Metallurgical Society. Warrendale. PA. USA.

Shakiba, G., Abdollahi, H., Gharabaghi, M., Mahroomi, M., Kiani, F. (2025). High performance-green extraction of base metals (Zn and Pb) and gold from polymetallic sulfide concentrate using p-toluenesulfonic acid-based deep eutectic solvents. Sep. Purif. Technol. 373, 133538.

Shanghai Metals Market. (2026). www.metal.com

Siragi D. B.M., Hima, H.I., Natatou, I., Dubois, V. (2025). A comparative study of the adsorption kinetics of AuCN2− and AuS2O323− by prepared activated carbon. Res. Chem. 17, 102641.

Skibsted,, L.H., Bjerrum, J., Hvidt, A., Kjekshus, A., Klewe, Powell, D.L. (1974). The equilibrium between gold(I) and gold(III) in the ammonia system and the standard potentials of the couples involving gold, diamminegold(I), and tetramminegold(III). Acta Chem. Scand. 28a, 764-770.

Soleymani, M., Sadri, F., Zhang, S., Ghahreman, A. (2022). The role of thiosulfate and sulfite in gold thiosulfate electrowinning process: an electrochemical view. Process Saf. Environ. Protect. 166, 232-240.

Soto-Uribe, J.C., Valenzuela-Garcia, J.L., Salazar-Campoy, M.M., Parga-Torres, J.R., Tiburcio-Munive, G., Encinas-Romero, M.A., Vazquez-Vazquez, V.M. (2023). Gold extraction from a refractory sulfide concentrate by simultaneous pressure leaching/oxidation. Minerals 13, 116.

Steinhauser, G., Evers, J., Jakob, S., Klapotke, T. M., Oehlinge, G. (2008). A review on fulminating gold (Knallgold). Gold Bull. 41, 305–317.

Strategic Metals Invest (2026). www.strategicmetalsinvest.com

Streszewski, B., Jaworski, W., Pacławski, K., Csapó, E., Dékány, I., Fitzner, K. (2012). Gold nanoparticles formation in the aqueous system of gold(III) chloride complex ions and hydrazine sulfate-kinetic studies. Colloids Surf. Physicochem. Eng. Asp. 397, 63-72.

Sun, T.M., Yen, W.T. (1993). Kinetics of gold chloride adsorption onto activated carbon. Miner. Eng. 6, 17-29.

Syed, S. (2012). Recovery of gold from secondary sources-a review. Hydrometallurgy 115-16, 30-51.

Szymanowski. J. (1993). Hydroxyoximes in Copper Hydrometallurgy. CRC Press, Boca Raton. USA.

Tauson, V.L., Mironov, A.G., Smagunov, N.V., Bugaeva, N.G., Akimov, V.V. (1996). Gold in sulfides: state of the art of occurrence and horizons of experimental studies. Russian Geol. Geophys. 37, 1-11.

Tokkani, D., Dönmez, B. Ata, O.S. (2019). The leaching kinetics of gold from gold scraps in Cl2-saturated HCl solutions. Pamukkale Univ. J. Eng. Sci. 25, 893-898.

Tromp, M., Burgard, M., Leroy, M.J.F. (1988). Extraction of gold and silver cyanide complexes through supported liquid membranes containing macrocyclic extractants. J. Membr. Sci. 38, 295-300.

Ubaldini, S., Fornari, P., Massidda, R., Abbruzzese, C. (1998). An innovative thiourea gold leaching process. Hydrometallurgy 48, 113-124.

Ubaldini, S., Vegliò, F., Fornari, P., Abbruzzese, C. (2000). Process flow-sheet for gold and antimony recovery from stibnite. Hydrometallurgy 57, 187-199.

Ubiç, S., Nekouei, R.K., Sahajwalla. V. (2024). A two-step leaching process using thiourea for the recovery of precious metals from waste printed circuit boards. Waste 2, 312-336.

Unknown author. (2021). The safe and effective use of cyanide. Society for Mining, Metallurgy & Exploration (SME), Englewood, USA. https://smenet.org/docs/public/SafeAndEffectiveUseOfCyanideInTheMiningIndustry.pdf. (Accessed December 2025).

Unknown author. (2024). Benzene: toxicological overview. UK Health Security Agency. https://www.gov.uk/government/publications/benzene-general-information-incident-management-and-toxicology/benzene-toxicological-overview

Urbanski, T.S., Fornari, P., Abbruzzese, C. (2000). Gold electrowinning from aqueous–alcoholic thiourea solutions. Hydrometallurgy 55, 137-152.

National Toxicology Program (2021). U.S. Department of Health and Human Services. 15th Report on Carcinogens.

U.S. Geological Survey (2025). Mineral commodity summaries 2025.

Van den Bossche, A., De Witte, E., Dehaen, W., Binnemans, K. (2018). Trihalide ionic liquids as non-volatile oxidizing solvents for metals). Green Chem. 20, 3327-3338.

Vukcevic, S. (1996). A comparison of alkali and acid methods for the extraction of gold from low grade ores. Miner. Eng. 9, 1033-1047.

Wang, Z., Chen, D., Chen, L. (2007). Gold cementation from thiocyanate solutions by iron powder. Miner. Eng. 20, 581-590.

Wang, H.J., Feng, Y.L., Li, H.R., Kang, J.X. (2019). The separation of gold and vanadium in carbonaceous gold ore by one-step roasting method. Powder Technol. 355, 191–200.

Wang, R., Fan, G., Zhang, C. (2024). Process and systematic study of gold recovery from flexible printed circuit boards (FPCBs) using a choline chloride–ethylene glycol system. Waste Manag. 178, 351-361.

Wang, Q., Liu, T., Li, Y., Nie, Y. (2025a). Synthesis of coal-based activated carbon via one-step activation and its adsorption and stripping performance for gold thiosulfate complexes. Hydrometallurgy 236, 106534.

Wang. W., Liu, Q., Dai, G., Xu, W., Yi, M., Tang, K. (2025b). Anion-exchange/coordination synergistic strategy for efficient gold recovery from e-waste by ionic liquids. J. Environ. Chem. Eng. 13, 118555.

Wang, D., Zeng, Y., Liang, Y., Chen, Y., Liu, C., Zhan, C., Chen, P., Sun, K., Song; S., Jia, F. (2025c). Pilot-scale, cost-effective waste resource recovery: Efficient reduction of trace Au(I) from industrial wastewater via an adsorption and electrodeposition coupling process. Sep. Purif. Technol. 361, Part 3, 131641.

Warshawsky, A., Kahana, N., Kampel, V., Rogachev, I., Kautzmann, R.M., Cortina, J.L., Sampaio, C.H. (2001). Ion exchange resins for gold cyanide extraction containing a piperazine functionality, 2. Study of the gold extraction reaction. Macromol. Mater. Eng. 286, 285-295.

Wojnicki, M., Luty-Błocho, M., Socha, R.P., Mech, K., Pedzich, Z., Fitzner, K., Rudnik, E. (2015).. Kinetic studies of sorption and reduction of gold(III) chloride complex ions on activated carbon Norit ROX 0.8. J. Ind. Eng. Chem. 29, 289–297.

Wołowicz, A., Hubicki, Z. (2012). The use of the chelating resin of a new generation Lewatit MonoPlus TP-220 with the bis-picolylamine functional groups in the removal of selected metal ions from acidic solutions. Chem. Eng. J. 197, 493-508.

Wu, J., Ahn, J., Lee, J. (2021). Gold deportment and leaching study from a pressure oxidation residue of chalcopyrite concentrate. Hydrometallurgy 201, 105583.

Xiao, H., Jin, J., He, F., Han, Y., Sun, Y. (2022). Strengthening gold extraction from carbonaceous gold ore based on decarburization by two-stage fluidized oxidation roasting. Minerals 12, 1620.

Xing, Z., Cheng, G., Yang, H., Xue, X., Jiang, P. (2020). Mechanism and application of the ore with chlorination treatment: a review. Miner. Eng. 154, 106404.

Xiong, C., Liang, K., Wu, C., Wu, W., Rao, X., Chen, Q. (2025). Preparation of ionic covalent organic frameworks and its efficient recovery of gold from e-waste. Sep. Purif. Technol. 379, Part 1, 134807.

Xu, B., Li, K., Dong, Z., Yang, Y., Li, Q., Liu, X., Jiang, T. (2019). Eco-friendly and economical gold extraction by nickel catalyzed ammoniacal thiosulfate leaching-resin adsorption recovery. J. Clean. Prod. 233, 1475-1485.

Xu, Q., Zhang, H., Li, H., Zhang, G., Fang, Z., Zhang, Y. (2025). Thiourea-linked covalent triazine frameworks enable efficient and selective gold recovery from e-waste leachate. Sep. Purif. Technol. 359, Part 1, 130506.

Xue, Y., Langhans, J., McPartland, J., Dragusanu, C., Lun, M., Jin, J. (2025). Characterization of carbonaceous materials in a gold loading study by micro-XRF imaging and Raman spectroscopy. Mining Metallurgy & Exploration 42, 2543-2556.

Yang, X., Moats, M.S., Miller, J.D. (2010). The interaction of thiourea and formamidine disulfide in the dissolution of gold in sulfuric acid solutions. Miner. Eng. 23, 698-704.

Yang, Y., Lai, M., Zhong, Q., Li, Q., Xu, B., Jiang, T. (2019). Study on intensification behavior of bismuth ions on gold cyanide leaching. Metals 9, 362.

Yang, Y., Hu, X., Zi, F., Chen, S., Zhao, L., Li, X., Lin, Y. (2024). Effectively adsorb Au(S2O3)23− using aminoguanidine as trapping group from thiosulfate solution. Environ. Sci. Pollut. Res. 31, 38298-38309.

Yannopoulos, J.C. (1991). The Extractive Metallurgy of Gold. Van Nostrand Reinhold, New York, USA.

Yu, L., Li, S., Liu, Q., Deng, J., Luo, B., Liang, Y., Zhao, L., Lai, H. (2019). Gold recovery from refractory gold concentrates by pressure oxidation pre-treatment and thiosulfate leaching. Physicochem. Probl. Miner. Process. 55, 537-551.

Zeng, X., Li, J., Xie, H., Liu, L. (2013). A novel dismantling process of waste printed circuit boards using water-soluble ionic liquid. Chemosphere 93, 1288-1294.

Zhang, H., Ritchie, I.M., La Brooy, S.R. (2004). The adsorption of gold thiourea complex onto activated carbon. Hydrometallurgy 72, 291-301.

Zhang, Y., Li, Q., Liu, X., Jiang, T. (2022), A thermodynamic analysis on thiosulfate leaching of gold under the catalysis of Fe3+/FeI complexes. Miner. Eng. 180, 107511.

Zhao, M., Zhen Huang, Z., Shixing Wang, S., Zhang, L., Wang, C. (2020). Experimental and DFT study on the selective adsorption mechanism of Au(III) using amidinothiourea-functionalized UiO-66-NH2. Micropor. Mesopor. Mat. 294, 109905.

Zhao, L., Qu, W., Hu, X., Zi, F. (2025). A tailored nitrogen-rich polymer for highly efficient and selective capture of gold from waste printed circuit boards. Waste Manag. 208, 115174.

Zhou, H.-C., Long, J.R., Yaghi, O.M. (2012). Introduction to metal–organic frameworks. Chem. Rev. 112, 673-674.

Zhu, J., Huang, K. (2022). Selective recovery of gold from dilute aqua regia leachate of waste printed circuit board by thiol-modified garlic peel. Environ. Sci. Pollut. Res. Int. 29, 55990-56003.

Zoleta, J., Aikawa, K., Okada, N., Park, I., Ito, M., Elakneswaran, Y., Hiroyoshi, N. (2024). Role of semiconductive property on selective cementation mechanism of iron oxides to gold in galvanic interaction with zero-valent aluminum from gold–copper ammoniacal thiosulfate solutions. Metals 14, 550.