Combined scheme for conditioning circulating cyanide solutions

Due to the specific features of hydrometallurgical processing, where cyanide solutions are used, the composition of the leaching solution undergoes periodic changes referred to in the literature as “fatigue.” This adversely affects the rate of gold recovery and cementation, and therefore the overall efficiency of cyanide leaching technology. One of the most important markers determining the “fatigue” of the solution is copper. This study examined the possibility of applying a combined scheme for the purification of circulating cyanide solutions with high concentrations of copper (1196 mg/dm³), iron (111 mg/dm³), arsenic (19 mg/dm³), and sodium cyanide (0.94 g/dm³). A two-stage technology (reverse osmosis + chemical precipitation) was developed for the reduction of treated solution volumes and the removal of impurities. At the first stage, the solution was separated in a reverse osmosis unit equipped with LP22-8040 membranes, producing permeate and concentrate in a 1 : 1 ratio. The permeate (12 mg/dm³ Cu and 0.01 mg/dm³ Fe, pH = 11.13) was returned to the process cycle. At the second stage, the concentrate, which contained 99 % of the initial impurities, was further purified by the stepwise addition of a CuSO₄ solution (70 g/dm³ Cu) in 1–11 cm³ doses under stirring (500 rpm, 10 min). The results showed that the optimal CuSO₄ dose (11 cm³) provided removal of more than 86 % of Cu from the initial solution, as well as 100 % of Fe and more than 96 % of As. The precipitate obtained in the process consisted of 68.3 % copper, with CuCN and Cu(OH)₂ as the main components.

1. Plaksin I.N. Metallurgy of Precious Metals. Moscow: Metallurgizdat, 1958. 366 p. (In Russ.). Плаксин И.Н. Металлургия благородных металлов. М.: Металлургиздат, 1958. 366 с.

2. Samofeev A.M., Abdrakhmanova A.S., Lobanov V.G., Pomortsev V.N. Research on the Features of Gold Leaching from the Flotation Concentrate of LLC “Berezovski rudnik”. In: Scientific foundations and practice of ore and technogenic raw: Materials of the XXVIII Scientific-Practical Conference (Ekaterinburg, 6–7 April 2023). Yekaterinburg: FortDialog, 2023. P. 277–280. (In Russ.).

3. Maslenitskiy I.N., Chugaev L.V., Borbat V.F. Metallurgy of precious metals (Ed. L.V. Chugaev). 2nd ed., revised and supplemented. Moscow: Metallurgiya, 1987. 432 p. (In Russ.).

4. Sceresini B. Gold-copper ores. In: Developments in Mineral Processing (Eds. Mike D., Adams B.A.). Amsterdam: Elsevier, 2005. Vol. 15. P. 789—824.

5. Gonzalo Larrabure J.C., Rodrнguez-Reyes J.C.F. A review on the negative impact of different elements during cyanidation of gold and silver from refractory ores and strategies to optimize the leaching process. Minerals Engineering. 2021;173:107194. https://doi.org/10.1016/j.mineng.2021.107194

6. Barchenkov V.V. Mineral processing and hydrometallurgical processes for gold extraction from ores. Vladimir: Transit-IKS, 2022. 544 p. (In Russ.).

7. Maganga S., Wikedzi A., Budeba M., Manyele S. Overview of the challenges and opportunities in processing complex gold-copper ores. Mining, Metallurgy & Exploration. 2023;40:1—18. https://doi.org/10.1007/s42461-023-00854-7

8. Medina D., Anderson C. A review of the cyanidation treatment of copper-gold ores and concentrates. Metals. 2020;10(7):897. https://doi.org/10.3390/met10070897

9. Yilmaz E., Ahlatci F., Celep O., Yazэcэ E., Deveci H. Interference of metals with the determination of free cyanide. In: Proceedings of the 14th International Mineral Processing Symposium (Kusadasi, Turkey, 15—17 October 2014). 2014. P. 1027—1033. https://doi.org/10.13140/2.1.3302.3682

10. Adams M.D. Advances in gold ore processing. Guildford: Elsevier Science & Technology, 2001. 1076 p.

11. Estay H., Ruby-Figueroa R., Gim-Krumm M., Quilaqueo M., Seriche G., Díaz-Quezada S., Cortés I., Barros L. The SuCy process: A more efficient and safer technology to recover cyanide and copper in cyanidation plants. In: Proc. of 12th International Conference on Process Hydrometallurgy (Hydroprocess 2020). 2020. https://doi.org/10.13140/RG.2.2.10213.63208

12. Seriche G., Quilaqueo M., Barros L., Gim-Krumm M., Cortés I., Troncoso E., Ruby-Figueroa R., Estay H. Integrated membrane process coupled with metal sulfide precipitation to recover zinc and cyanide. Minerals. 2022;12(2):229. https://doi.org/10.3390/min12020229

13. Parga J.R., Valdés J.V., Valenzuela J.L., Gonzalez G., Pérez L.M.J., Cepeda T.F. New approach for lead, zinc and copper ions elimination in cyanidation process to improve the quality of the precipitate. Materials Sciences and Applications. 2015;6:117—129. https://doi.org/10.4236/msa.2015.62015

14. Estay H., Gim-Krumm M., Seriche G., Quilaqueo M., Barros L., Ruby-Figueroa R., Romero J., Troncoso E. Optimizing the SART process: A critical assessment of its design criteria. Minerals Engineering. 2020;146:106116. https://doi.org/10.1016/j.mineng.2019.106116

15. Alonso-González O., Nava-Alonso F., Uribe-Salas A. Copper removal from cyanide solutions by acidification. Minerals Engineering. 2009;22:324—329. https://doi.org/10.1016/j.mineng.2008.09.004

16. Kassymova D., Sapinov R., Kushakova L., Kulenova N., Shoshay Z., Adylkanova M. Optimization of copper recovery from cyanide leaching solutions used in gold— copper ore processing using probabilistic—deterministic experimental design. Processes.2025;13(1):61. https://doi.org/10.3390/pr13010061

17. Meretukov M.A., Orlov A.M. Metallurgy of precious metals: foreign experience. Moscow: Metallurgiya, 1990. 416 p. (In Russ.).

18. Knorre H., Griffiths A. Cyanide detoxification with hydrogen peroxide using Degussa process. In: Proc. of Conference on Cyanide and the Environment (Tucson, Arizona, 1984). Ed. by D. Van Zyl. Colorado State University, 1995. Vol. 2. P. 519—530.

19. Chen F., Zhao X., Liu H., Qu J. Reaction of Cu(CN)3 2– with H2O2 in water under alkaline conditions: Cyanide oxidation, Cu+/Cu2+ catalysis and H2O2 decomposition. Applied Catalysis B: Environmental. 2014;158-159:85—90. https://doi.org/10.1016/j.apcatb.2014.04.010

20. Sarla M., Pandit M., Tyagi D.K., Kapoor J. Oxidation of cyanide in aqueous solution by chemical and photochemical process. Journal of Hazardous Materials. 2005;116(1-2):49—56. https://doi.org/10.1016/j.jhazmat.2004.06.035

21. Goyburo-Chávez C., Mendez-Ruiz J.I., JiménezOyola S., Romero-Crespo P., Gutierrez L., ValverdeArmas P.E. Pilot-scale reverse osmosis treatment of gold cyanidation effluent for the removal of cyanide, heavy metal(loid)s, and ionic species. Case Studies in Chemical and Environmental Engineering. 2024;9:100688. https://doi.org/10.1016/j.cscee.2024.100688

22. Vásquez Salazar E.E., Hurtado Bolaños F.P. Cyanide compounds removal efficiency in a reverse osmosis system using a water supply from a co-precipitation chemical process. Desalination and Water Treatment. 2021;229:235—242. https://doi.org/10.5004/dwt.2021.27390

23. Pabby A.K., Rizvi S.S.H., Sastre A.M. (Eds.) Handbook of membrane separations: Chemical, pharmaceutical, food, and biotechnological applications. 3rd ed. Boca Raton: CRC Press, 2022. 1200 p. https://doi.org/10.1201/9781003285656

24. Samaei S.M., Gato-Trinidad S., Altaee A. Performance evaluation of reverse osmosis process in the post-treatment of mining wastewaters: Case study of Costerfield mining operations, Victoria, Australia. Journal of Water Process Engineering. 2020;34:101116. https://doi.org/10.1016/j.jwpe.2019.101116

25. Method for copper recovery from cyanide solutions and cyanide regeneration: Patent Application No. 2024137940 (RF). 2024. (In Russ.).