Gold Cyanidation Behavior of Limonitic Ores from the Carajás Province, Brazil: Mineralogical Controls, Cyanide Consumption, and Leaching Kinetics.

Limonitic gold ores constitute an important resource for global gold production; however, their mineralogical heterogeneity and the occurrence of cyanide-consuming phases may significantly influence metallurgical performance and operating costs. This study investigates the cyanidation behavior of gold-bearing limonitic ores from the Carajás Mineral Province, northern Brazil, with emphasis on the relationships between mineralogical composition, gold extraction, cyanide consumption, and sulfur content. Four representative drill-core samples underwent detailed chemical and mineralogical characterization using ICP-OES, SEM-EDS, and QEMSCAN, followed by dynamic and kinetic cyanidation tests. An additional ten samples from the same limonitic weathering domain were evaluated through standardized 8 h cyanidation tests to validate the metallurgical response of the ore population.
The investigated ores contained between 14 and 77 wt.% iron oxyhydroxides, confirming variable degrees of lateritic weathering, while copper concentrations ranged from 0.02 to 0.30 wt.%. Dynamic cyanidation tests performed on material ground below 75 μm achieved average gold recoveries of approximately 89–90%, indicating predominantly free-milling behavior. Kinetic leaching experiments demonstrated rapid gold dissolution, with approximately 90% of the final recovery achieved within 8 h of cyanidation, corresponding to an average sodium cyanide consumption of approximately 650 g NaCN/t ROM. Mineralogical observations revealed that copper-bearing phases were the primary contributors to cyanide consumption, whereas iron oxyhydroxides had little effect on gold extraction efficiency.
The expanded dataset comprising fourteen samples confirmed the favorable cyanidation characteristics of the limonitic ores, with most samples exhibiting gold recoveries above 90%. Statistical analysis further indicated a strong inverse relationship between sulfur content and gold recovery, suggesting that residual sulfide mineralization may locally reduce cyanidation performance despite the predominantly oxidized nature of the deposit. These findings demonstrate the importance of integrating mineralogical characterization, kinetic leaching studies, and statistical validation to optimize cyanidation performance and support the development of efficient processing routes for oxidized gold deposits.

Gold cyanidation; Limonitic ore; Lateritic gold deposit; Gold extraction; Cyanide consumption; Copper minerals; Leaching kinetics; Carajás Province

1. Asamoah, R. K., Zanin, M., Addai-Mensah, J., & Skinner, W. (2021). Refractory gold ores and concentrates Part 1: Mineralogical and physico-chemical characteristics. Mineral Processing and Extractive Metallurgy, 128(4), 173–195. https://doi.org/10.1080/25726641.2019.1626659. [Google Scholar] [Crossref]

2. Bracamontes-Landavazo, M. A., Valenzuela-García, J. L., Parga-Torres, J. R., & Guerrero-German, P. (2024). Kinetic study for the extraction of gold and silver from an ore comparing lixiviants sodium cyanide and DEZO using moderate pressures. Mining, Metallurgy & Exploration, 41(5), 2589–2602. https://doi.org/10.1007/s42461-024-01036-9. [Google Scholar] [Crossref]

3. Bragin, V. I., Makarov, V. A., Usmanova, N. F., Samorodskii, P. N., Lobastov, B. M., & Vashlaev, A. I. (2019). Mineralogical examination of gold processing plant tailings. Journal of Mining Science, 55(1), 149–156. https://doi.org/10.1134/S1062739119015407. [Google Scholar] [Crossref]

4. Chen, G., Zhao, H., Zhou, J., Liu, Z., & Yang, H. (2025). Process mineralogy study and flotation testwork of a complex lead–gold rougher concentrate. Minerals, 15(9), 967. https://doi.org/10.3390/min15090967. [Google Scholar] [Crossref]

5. Chen, J., Zhong, S., Tang, D., & Kuang, C. (2020). Practical experience in large-scale development of Zijinshan low-grade gold-copper mine. Mining, Metallurgy & Exploration, 37(4), 1339–1347. https://doi.org/10.1007/s42461-020-00237-2 [Google Scholar] [Crossref]

6. Chen, Z., Li, P., Wang, Q., & Dai, S. (2024). Study on adsorption of kaolinite and gold thiosulfate. Scientific Reports, 14, 15486. https://doi.org/10.1038/s41598-024-66389-z. [Google Scholar] [Crossref]

7. Chingwaru, S. J., Tadie, M., & von der Heyden, B. (2025). Characterization of gold in complex historical refractory tailings for enhanced process optimization. Mineral Processing and Extractive Metallurgy Review, 46(2), 193–209. https://doi.org/10.1080/08827508.2023.2298728. [Google Scholar] [Crossref]

8. Chingwaru, S.J., Von der Heyden, B. & Tadie, M. An underexploited invisible gold resource in the Archean sulphides of the Witwatersrand tailings dumps. Sci Rep 13, 3086 (2023). https://doi.org/10.1038/s41598-023-30219-5. [Google Scholar] [Crossref]

9. Costa, F. R., Nery, G. P., Carneiro, C. C., Kahn, H., & Ulsen, C. (2022). Mineral characterization of low-grade gold ore to support geometallurgy. Journal of Materials Research and Technology, 21, 4303–4317. https://doi.org/10.1016/j.jmrt.2022.10.085. [Google Scholar] [Crossref]

10. Deveci, H., Yazıcı, E. Y., Celep, O., & Mercimek, M. (2022). Effects of lead nitrate and pre-aeration on the deportment of base/precious metals in cyanide leaching of a pyritic refractory gold concentrate. In Proceedings of the 17th International Mineral Processing Symposium (IMPS 2022). Istanbul, Türkiye. [Google Scholar] [Crossref]

11. Grangeiro, L. C., Bevilaqua, D., Oliveira, K. B., Palmieri, M. C., & Macêdo, E. N. (2017). Avaliação do potencial biotecnológico para o tratamento de um minério de ouro de uma mina do estado do Amapá. Tecnologia em Metalurgia, Materiais e Mineração, 14(2), 107–118. https://doi.org/10.4322/2176-1523.1079. [Google Scholar] [Crossref]

12. Guner, M. K., Bulut, G., Hassanzadeh, A., Lode, S., & Aasly, K. (2023). Automated mineralogy and diagnostic leaching studies on bulk sulfide flotation concentrate of a refractory gold ore. Minerals, 13(10), 1243. https://doi.org/10.3390/min13101243. [Google Scholar] [Crossref]

13. Huang, F.-X., Wu, Y.-F., Evans, K., Williams-Jones, A. E., Zhao, X.-F., Wei, Y., Feng, W., & Li, J.-W. (2025). Adsorption and coarsening of gold nanoparticles in iron (oxyhydr)oxides lead to high-grade gold mineralization. Geochimica et Cosmochimica Acta, 404, 1–12. https://doi.org/10.1016/j.gca.2025.07.013. [Google Scholar] [Crossref]

14. Jia, Y., Wang, X., Cheng, W., & Ma, S. (2019). Research progress on non-cyanide leaching of refractory gold ores. Chinese Journal of Engineering, 41(3), 307–315. https://doi.org/10.13374/j.issn2095-9389.2019.03.003. [Google Scholar] [Crossref]

15. Lee, S., Sadri, F., & Ghahreman, A. (2024). Exploring non-ammoniacal thiosulfate gold leaching and limited gold recovery from a refractory gold ore oxidized in alkaline pressure conditions. Journal of Sustainable Metallurgy, 10(2), 486–496. https://doi.org/10.1007/s40831-024-00807-4. [Google Scholar] [Crossref]

16. Liu, X., Wang, Y., Han, P., Yan, J., & Ye, S. (2021). Leaching of gold from micro-disseminated oxidized gold ore by thiosulfate method. Mining and Metallurgy, 30(3). https://doi.org/10.3969/j.issn.1005-7854.2021.03.017. [Google Scholar] [Crossref]

17. Liu, X., Wang, Y., Xiao, L., Ma, L., Han, P., & Ye, S. (2022). Eco-friendly and rapid extraction of gold by in-situ catalytic oxidation with N-bromosuccinimide. Heliyon, 8(6), e09706. https://doi.org/10.1016/j.heliyon.2022.e09706. [Google Scholar] [Crossref]

18. Nicol, M. J. (2022). Hydrometallurgy: Theory (1st ed.). Elsevier. https://doi.org/10.1016/C2020-0-03551-. [Google Scholar] [Crossref]

19. Ofori-Sarpong, G., Adam, A.-S., Asamoah, R. K., & Amankwah, R. K. (2020). Characterisation of biooxidation feed and products for improved understanding of biooxidation and gold extraction performance. International Journal of Mineral Processing and Extractive Metallurgy, 5(2), 20–29. https://doi.org/10.11648/j.ijmpem.20200502.11. [Google Scholar] [Crossref]

20. Pereira, A. C., Barbosa, V. da S. B., & Rodrigues, M. L. M. (2017). Effectiveness of acidic pre-cleaning for copper-gold ore. REM - International Engineering Journal, 70(4), 445–450. DOI: 10.1590/0370-44672016700126 [Google Scholar] [Crossref]

21. Pereira, A. C., Gomes, M. R. dos S., & Manfridini, A. P. D. A. (2018). Ensaios exploratórios de lixiviação para ouro associado a minérios limoníticos / Exploratory tests for leaching gold associated with limonitic ore. Brazilian Applied Science Review, 3(2). https://doi.org/10.34115/basr.v3i2.998 [Google Scholar] [Crossref]

22. Qin, X., Hu, X., Li, J., Fu, Y., Wang, Q., Chen, Y., Wang, C., & coauthors. (2021). Effect of lead ions on gold dissolution in the Cu²⁺–en–S₂O₃²⁻ system. Hydrometallurgy, 196, 105430. https://doi.org/10.1016/j.hydromet.2020.105430. [Google Scholar] [Crossref]

23. Roostaei, H., Kordparijaei, M., & Mesroghli, S. (2025). Gold-bearing iron oxides processing based on ore characterization: Gravity pre-concentration and cyanide dissolution. Journal of Sustainable Metallurgy, 11(3), 3156–3168. https://doi.org/10.1007/s40831-025-01195-z. [Google Scholar] [Crossref]

24. Roostaei, H., Kordparijaei, M., & Mesroghli, S. (2026). Cyanide dissolution of gold-bearing iron oxide minerals: Kinetic studies and optimization using response surface methodology. Discover Applied Sciences, 8, 388. https://doi.org/10.1007/s42452-026-08420-8. [Google Scholar] [Crossref]

25. Sekisov, A., & Rasskazova, A. (2021). Assessment of the possibility of hydrometallurgical processing of low-grade ores in the oxidation zone of the Malmyzh Cu-Au porphyry deposit. Minerals, 11(1), 69. https://doi.org/10.3390/min11010069 [Google Scholar] [Crossref]

26. Sevgül, S., Oluklulu, S., & Bozkurt, V. (2022). Concentration of an oxidized gold ore by the Knelson concentrator. In Proceedings of the 17th International Mineral Processing Symposium (IMPS 2022) (pp. 225–231). Istanbul, Türkiye. [Google Scholar] [Crossref]

27. Sitando, O., Senanayake, G., Dai, X., & Breuer, P. (2019). The adsorption of gold(I) on minerals and activated carbon (preg-robbing) in non-ammoniacal thiosulfate solutions: Effect of calcium thiosulfate, silver(I), copper(I), and polythionate ions. Hydrometallurgy, 183, 206–217. https://doi.org/10.1016/j.hydromet.2018.10.016 [Google Scholar] [Crossref]

28. Soleymani Naeini, M. (2022). Electrochemical study of gold thiosulfate extraction process (Doctoral dissertation, Queen's University). Queen's University Research Repository. http://hdl.handle.net/1974/30384 [Google Scholar] [Crossref]

29. Stephen, R. S., Anuar, W. N. S., Ismail, S., & Jabit, N. A. (2021). Characterisation and diagnostic leaching of gold-bearing mineral ore, East Coast Peninsular Malaysia. Malaysian Journal of Microscopy, 17(2). https://malaysianjournalofmicroscopy.org/ojs/index.php/mjm/article/view/535 [Google Scholar] [Crossref]

30. Weng, Q., Zhan, W., Zhang, X., Song, S., Zeng, Z., Lwin, H. M., Arauz-Lara, J. L., & Jia, F. (2025). Electrochemical reduction and recovery of trace gold(I) from environmentally friendly thiosulfate leaching solutions using carbon electrodes. Carbon, 232, 119799. https://doi.org/10.1016/j.carbon.2024.119799 [Google Scholar] [Crossref]

31. Yanbo, C., Qin, G., Li, G., & Zhu, X. (2021). Experimental study on thiosulfate leaching of gold from a high copper gold concentrate. E3S Web of Conferences, 271, 04001. https://doi.org/10.1051/e3sconf/202127104001. [Google Scholar] [Crossref]

• Assessment of the Role of Artificial Intelligence in Repositioning TVET for Economic Development in Nigeria
• Teachers’ Use of Assure Model Instructional Design on Learners’ Problem Solving Efficacy in Secondary Schools in Bungoma County, Kenya
• “E-Booksan Ang Kaalaman”: Development, Validation, and Utilization of Electronic Book in Academic Performance of Grade 9 Students in Social Studies
• Analyzing EFL University Students’ Academic Speaking Skills Through Self-Recorded Video Presentation
• Major Findings of The Study on Total Quality Management in Teachers’ Education Institutions (TEIs) In Assam – An Evaluative Study