Irgiredmet JSC (Irkutsk Research & Development Center for Precious and Rare Metals and Diamonds), Irkutsk, Russia:

A. V. Epiforov, Senior Researcher, Сandidate of Technical Sciences, e-mail: epiforov@irgiredmet.ru
S. V. Balikov, Principal Researcher, Doctor of Technical Sciences, e-mail: balikov@irgiredmet.ru

A. A. Lukianov, Senior Researcher, Postgraduate Student, e-mail: laa@irgiredmet.ru

Irgiredmet JSC (Irkutsk Research & Development Center for Precious and Rare Metals and Diamonds), Irkutsk, Russia¹ ; Irkutsk National Research Technical University (INRTU), Irkutsk, Russia²:
A. A. Shipnigov, Engineer¹, Master’s Student², e-mail: shipn.anton@yandex.ru

The standard pressure oxidation (POX) technology for sulfide gold-bearing concentrates processing has many problems associated with the use of cyanide as a gold lixiviant. Therefore, works to find of alternative gold recovery methods are currently now. This paper describes some technological solutions, which can become a real alternative to cyanide technology in the future. Five different refractory gold-bearing concentrates from Russian gold deposits were investigated. Concentrate 1 was gold-copper concentrate. Concentrate 2 was gold-pyrite concentrate. Concentrates 3–5 were pyrite-arsenopyrite double refractory concentrates. The POX tests at the temperature of 110, 200 and 220 oC and the oxygen pressure of 1.5, 2.4 and 3.0 MPa were carried out. Chloride, thiosulfate, sulfite and thiocyanate were tested as gold lixiviants. The gold recovery by non-cyanide methods was 97–99%, and from double refractory concentrates was 86–92%. The tested reagents are less toxic than cyanide and makes possible to recover gold in acidic POX slurry. As well, “POX-pyrometallurgical” technology for precious metals recovery from POX cakes to lead collector was tested in pilot scale. It was shown that “POX-pyrometallurgical” technology for preg-robbing concentrates could be used. The recoveries of gold and silver are 97 and 96%, respec tively.

1. Epiforov A. V., Balikov S. V. Pressure oxidation as a universal method for processing sulphide concentrates of precious and base metals. 29^th International Mineral Processing Congress – IMPC-2018. Moscow, 2018. pp. 3776–3789.
2. Balikov S. V., Gudkov S. S., Emelianov Yu. E., Bogorodskiy A. V., Epiforov A. V. et al. Pressure oxidation of gold ores and concentrates. Irkutsk : OAO “Irgiredmet”, 2016. 471 p.
3. Kaplan S. F., Dolotov A. S., Kovalev V. N. Influence of halide and pseudohalide ions on gold extraction from double refractory concentrates in POX-CIL process. 29^th International Mineral Processing Congress – IMPC-2018. Moscow, 2018. pp. 2782–2790.

4. Pat. 5851499 US. Gathje J. C., Simmons G. L. Method for pressure oxidizing gold-bearing refractory sulfide ores having organic carbon. Published: 1998.
5. Pat. 2514900 RF. Shneerson Ya. M., Chugaev L. V., Fedorov V. K., Lapin A. Yu., Zaytsev P. V. et al. Processing of double refractory gold-bearing concentrates. Applied: 04.07.2012. Published: 10.01.2014. Bulletin No. 1.
6. Kaplan S. F., Dolotov A. S., Kovalev V. N. Utilization of highly saline recycling industrial water and its influence on the extraction of gold from double refractory concentrates in the framework of autoclave technology (POX-CIL). 29^th International Mineral Processing Congress – IMPC-2018. Moscow, 2018. pp. 2791–2799.
7. Zaytsev P., Shneerson Ya., Fedorov V., O’Callaghan J., Haakana T. et al. Pokrovskiy pressure oxidation (POX) hub. Proceedings of ALTA 2013. Gold Session. Perth, 2013. pp. 33–66.
8. Aylmore M. G. Alternative Lixiviants to Cyanide for Leaching Gold Ores. Gold Ore Processing. Mike D. Adams (Editor). Chapter 27. 2016. pp. 447–484. DOI: 10.1016/B978-0-444-63658-4.00027-X.
9. Pat. 6315812 US. Fleming C. A., Dreisinger D. B., O'Kane P. T. Oxidative pressure leach recovery using halide ions. Published: 2001.
10. Ferron C. J., Fleming C. A., O’Kane P. T., Dreisinger D. Pilot plant demonstration of the PLATSOL™ process for the treatment of the NorthMet copper-nickel-PGM deposit. Mining Engineering. 2002. Vol. 54, No. 12. pp. 33–39.
11. Ferron C. J., Fleming C. A. Chloride as an alternative to cyanide for the extraction of gold — going full circle. SGS Minerals Services. Technical Paper. 2003. No. 1. pp. 1–10.
12. Dreisinger D. Keynote address: hydrometallurgical process development for complex ores and concentrates. Journal of the Southern African Institute of Mining and Metallurgy. 2009. Vol. 109. pp. 253–271.
13. Pat. 5785736 US. Thomas K. J., Fleming C., Marchbank A. R., Dreisinger D. Gold recovery from refractory carbonaceous ores by pressure oxidation, thiosulfate leaching and resin-in-pulp adsorption. Published: 1998.
14. Choi Y. Selecting the best process for the treatment of a refractory gold ore – Barrick’s experience. Proceedings of ALTA 2016. Perth, 2016. pp. 2–34.
15. Pat. 2528300 RF. Epiforov A. V., Gudkov S. S., Balikov S. V., Bogorodskiy A. V. Processing of sulphide stock containing precious metals. Applied: 19.11.2012. Published: 10.09.2014. Bulletin No. 25.
16. Epiforov A. V., Kozlov A. A., Nemchinova N. V., Seleznev A. N. The carbon adsorption of gold from thiocyanate containing sulfuric acid solutions of gold-copper float concentrates atmospheric leaching. Tsvetnye Metally. 2020. No. 1. pp. 38–44. DOI: 10.17580/tsm.2020.01.06
17. Kononova O. N., Kholmogorov A. G., Kononov Yu. S. Extraction of gold from solutions and slurries by sorption. Process chemistry, selectivity, technology. Krasnoyarsk : Sibirskiy federalnyi universitet, 2018. 200 p.
18. Pat. EAPO 026707 RU. Guriev V. V., Evtushevich I. I., Dzgoev Ch. T., Shtoyk S. G. et al. Method for extracting precious metals from refractory sulphide material. Applied: 22.01.2015. Published: 31.05.2017. Bulletin No. 5.
19. Chizhikov D. M. Metallurgy of lead. Moscow : Metallurgizdat, 1944. 398 p.
20. Sinclair R. J. Electrochemical Reduction Processes. The Extractive Metallurgy of Lead. 2009. Chapter 9. pp. 151–165.
21. Pat. 03060172 WO. High temperature pressure oxidation of ore and ore concentrates containing silver using controlled precipitation of sulfate species / Simmons G. L., Gathje J. C.; 2003.
22. Dzgoev Ch. T., Evtushevich I. I., Shtoik S. G., Gudkov S. S. et al. Pressure oxidation pyrometallurgical technology of gold-bearing and lead and zinc sulfide concentrates combined treatment. 28^th International Mineral Processing Congress. Proceedings — IMPC-2016. Cuébec. Canada. 2016. Paper No. 801.
23. Epiforov A. V., Bogorodskiy A. V., Balikov S. V., Emelianov Yu. E. et al. High-temperature pressure oxidation of polymetallic gold-bearing sulphide concentrates: A lab study. Vestnik Irkutskogo gosu darstvennogo tekhnicheskogo universiteta. 2012. No. 1. pp. 116–119.
24. Mikhailova A. N., Faiberg A. A., Gudkov S. S., Dementev V. Ye. New technology of base metals precipitation with hydrogen sulfide obtained using Desulfurella acetivorans and Desulfurella kamchatkensis. Advanced Materials Research. 2015. Vol. 1130. pp. 477–481.
25. Fleming C. A. Basic iron sulphate – a potential killer for pressure oxidation processing of refractory gold concentrates if not handled appropriately. SGS Minerals Services. Technical Paper. 2009. No. 6. pp. 1–10.
26. Pat. EAPO 017438 RU. Bogorodskiy A. V., Emelianov Yu. E., Balikov S. V. Method for processing raw materials containing noble metals and sulphides. Applied: 02.09.2009. Published: 29.04.2011.
27. Pat. 2447166 RF. Gudgeon A. S., Mineev G. G., Bogorodskiy A. V. Processing of sulphide stock containing precious metals. Applied: 16.06.2010. Published: 10.04.2012. Bulletin No. 10.
28. Epiforov A. V., Dzgoev Ch. T., Nabiulin R. N., Balikov S. V. Behaviour of gold during pressure oxidation of sulphide concentrates in the presence of chlorine. Plaksin Readings-2016. Saint Petersburg : MFK “Gornyi”, 2016. pp. 309–311.
29. Marchenko N. V., Vershinina E. P., Gildebrandt E. M. Metallurgy of heavy non-ferrous metals. Krasnoyarsk : Sibirskiy federalnyi universitet, 2009. 394 p.