Investigation of the kinetics of pyrite oxidation during electrochlorination

One of the important tasks of the gold mining industry is the involvement in the processing of hard-to-enrich gold-bearing ores. Processing of ores of this type is usually carried out according to complex combined schemes and modes combining gravity, flotation and chemical enrichment. Many gold-bearing ores contain gold inclusions in large quantities, which are found in pyrite, chalcopyrite, pyrrhotite and arsenopyrite and are difficult to enrich, since metals are not extracted from them by hydrometallurgy. Today, there is a need to find new technical solutions to reduce the cost and simplify production, as well as new technologies must meet modern requirements for environmental protection and environmental impact. In this article, in the course of experimental studies, the regularity of the displacement of the corrosion potential at different concentrations of sodium chloride during contact electrochlorination has been established, and the authors have also proposed a model of a group cell in which charge transfer processes occur at the contact and in the volume of mineral grains, electrolyte and through the solid-liquid phase boundaries. In the article, the parameters of the equivalent scheme of the group cell and electrochemical processes at the working electrode were calculated, the ratios of various electrochemical processes during contact electrochlorination were determined. The study of electrochemical processes occurring during the oxidation of difficult-to-enrich gold-bearing ores on the example of pyrite is a promising direction that can solve the problem of more complete extraction of gold and other valuable minerals.

Morozov Yu. P., Valtseva A. I., Pestryak I. V., Shevchenko A. S. Investigation of the kinetics of pyrite oxidation during electrochlorination. MIAB. Mining Inf. Anal. Bull. 2022;(11-1): 169—189. [In Russ]. DOI: 10.25018/0236_1493_2022_111_0_169.

Morozov Yu. P., Dr. Sci. (Eng.), Professor, Ural State Mining University, Kuybysheva st. 30, Yekaterinburg, Russia, 620144, e-mail: tails2002@inbox.ru, ORCID ID: 0000-0003-0554-5176;
Valtseva A. I., senior lecturer, Ural Federal University named after the first President of Russia B. N. Yeltsin, Mira st. 19, Yekaterinburg, Russia, 620002, e-mail: a.i.valtseva@urfu.ru;
Pestryak I. V., Dr. Sci. (Eng.), Professor, National Research Technological University, Moscow Institute of Steel and Alloys, Ministry of Education and Science of the Russian Federation, Leninsky Prospekt 4, Moscow, Russia,117049, e-mail:spestryak@mail.ru;
Shevchenko A. S., graduate student, Ural State Mining University, Kuybysheva st. 30, Yekaterinburg, Russia, 620144, e-mail: opi96@yandex.ru.

Valtseva A. I., e-mail: a.i.valtseva@urfu.ru.

1. Fedorov S. A., Amdur A. M., Malyshev A. N., Karimova P. F. Industrial and secondary gold-bearing waste and gold recovery techniques: Review. MIAB. Mining Inf. Anal. Bull. 2021;(11−1):346−365. [In Russ]. DOI: 10.25018/0236_1493_2021_111_0_346.

2. Khatkova A. N., Shumilova L. V., Pateuk S. A. Development of a waste-free technology for processing mineral raw materials, expanding the functionality of the mining and environmental concept. MIAB. Mining Inf. Anal. Bull. 2022;10:51−61. [In Russ]. DOI: 10.2 5018/0236_1493_2022_10_0_51.

3. Vasilyuk P. A., Razmakhnin K. K. Hydrometallurgical test data of oxidized gold ore from the North East site of the Delmachik deposit. MIAB. Mining Inf. Anal. Bull. 2020;(9):7786. [In Russ]. DOI: 10.25018/0236-1493-2020-9-0−77−86.

4. Aben E. Kh., Rustemov S. T., Bakhmambegov G. D., Akhmetkhanov D. Increased metal extraction based on activation of the leaching solution. MIAB. Mining Inf. Anal. Bull. 2019;(12):169—179. [In Russ]. DOI: 10.25018/0236-1493-2019-12-0-169-179.

5. Smirnov A. N., Klochkovskii S. P., Krylova S. A., Sysoev V. I. Study of high-magnesia iron ore feedstock integrated processing. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal = News of the Higher Institutions. Mining Journal. 2020; 8: 62–70 [In Russ.]. DOI: 10.21440/0536-1028-2020-8-62−70

6. Morozov Yu. P., Shevchenko A. S., Valtseva A. I. Combined processing technology of enrichment tailings. Scientific foundations and practice of processing ores and man-made raw materials. Proceedings of the XVII International scientific-practical conference, 2022, pp. 261−266. [In Russ].

7. Shevchenko A. S., Morozov Yu. P., Valtseva A. I., Bitimbayev M. Zh. Combined technology of processing of technogenic raw materials. Problems of complex and environmentally safe processing of natural and man-made mineral raw materials. Proceedings of the International scientific conference, 2021, pp. 478−481. [In Russ].

8. Baltazar C., Ryan T., Corpuz D., Igarashi T., Villacorte-Tabelin M., Ito M., Hiroyoshi N. Hematite-catalysed scorodite formation as a novel arsenic immobilisation strategy under ambient conditions. Chemosphere, vol. 233, 2019, pp. 946−953. DOI: 1016/j. chemosphere.2019.06.020.

9. Nicol M., Zhang S., Tjandrawan V. The electrochemistry of pyrite in chloride solutions. Hudrometallurgy, vol. 178, 2018, pp. 116−123. DOI: 10.1016/j.hydromet.2018.04.013.

10. Nicol M. Does galvanic coupling with pyrite increase the rate of dissolution of chalcopyrite under ambient conditions? An electrochemical study. Hudrometallurgy, vol. 208, 2022, 105824. DOI: 10.1016/j.hydromet.2022.105824.

11. Ahtiainen R., Liipo J., Lundstoem M. Simultaneous sulfide oxidation and gold dissolution by cyanide-free leaching from refractory and double refractory gold concentrates. Minerals Engineering, vol. 170, 2021, 107042. DOI: 10.1016/j.mineng.2021.107042.

12. Ahtiainen R., Lundstroem M., Liipo J. Preg-robbing verification and prevention in gold chloride-bromide leaching. Minerals Engineering, vol. 128, 2018, pp.153−159. DOI: 10.1016/j.mineng.2018.08.037.

13. Ahtiainen R., Lundstroem M. Cyanide-free gold leaching in exceptionally mild chloride solutions. Journal of Cleaner Production, vol. 234, 2019, pp. 9−17. DOI: 10.1016/j. jclepro.2019.06.197.

14. Dong Z., Zhu Y., Han Y., Gu X., Jiang K. Study of pyrite oxidation with chorine dioxide under mild conditions. Minerals Engineering, vol. 133, 2019, pp. 106–114. DOI: 10.1016/j.mineng.2019.01.018.

15. Elomaa H., Rintala L., Aromaa J., Lundstroem M. Open circuit potential and leaching rate of pyrite in cupric chloride solution. Canadian Metallurgical Quarterly, vol. 57 (4), 2018, pp. 416–421. DOI: 10.1080/00084433.2018.1477652.

16. Wang Q., Hu X., Zi F., Qin X., Nie Y., Zhang Y. Extraction of gold from refractory gold ore using bromate and ferric chloride solution. Minerals Engineering, vol. 136, 2019, pp. 89–98. DOI: 10.1016/j.mineng.2019.02.037.

17. Wang J., Zeng H. Recent advances in electrochemical techniques for characterizing surface properties of minerals. Advances in Colloid and Interface Science, vol. 288, 2021, 102346. DOI: 10.1016/j.cis.2020.102346.

18. Liu T., Hu Y., Chen N., He Q., Feng Ch. High redox potential promotes oxidation of pyrite under neutral conditions: Implications for optimizing pyrite autotrophic denitrification. Journal of Hazardous Materials, vol. 416, 2021, 125844. DOI: 10.1016/j. jhazmat.2021.125844.

19. Liu T., Hu Y., Chen N., Xue L., Feng Ch., Ye Yu. Electrochemical investigation of the oxidation of pyrite in neutral solutions. Electrochimica Acta, vol. 393, 2021, 139078. DOI: 10.1016/j.electacta.2021.139078.

20. Jaramillo K., Vargas T. Kinetics of cupric leaching of pyrite in 4 M NaCl solutions. Canadian Metallurgical Quarterly, vol. 59 (3), 2020, pp. 360−367. DOI: 10.1080/00084433.2020.1780559.

21. Lampinen M, Seisko S, Forsström O, et al. Mechanism and kinetics of gold leaching by cupric chloride. Hydrometallurgy, vol. 169, 2017; pp. 103–111. DOI: 10.1016/j. hydromet.2016.12.008.

22. Zha L., Li H., Wang N. Electrochemical Study of Galena Weathering in NaCl Solution: Kinetics and Environmental Implications. Minerals, vol. 10(5) no. 416, 2020. DOI: 10.3390/min10050416.

23. Aikawa K., Ito M., Segawa T., Jeon S., Park I., Tabelin C. B., Hiroyoshi N. Depression of lead-activated sphalerite by pyrite via galvanic interactions: Implications to the selective flotation of complex sulfide ores. Minerals Engineering, vol. 152, 2020, 106367. DOI: 10.1016/j.mineng.2020.106367.

24. Consolazio N., Lowry G. V., Karamalidis A. K. Hydrolysis and degradation of dazomet with pyrite: Implications for persistence in produced waters in the Marcellus Shale. Applied Geochemistry, vol. 108, 2019, 104383. DOI: 10.1016/j.apgeochem.2019.104383.

25. Johnson A. C. Experimental determination of pyrite and molybdenite oxidation kinetics at nanomolar oxygen concentrations. Geochimica Et Cosmochimica Acta, vol.249, 2019, pp. 160−172. DOI: 10.1016/j.gca.2019.01.022.

26. Li L., Ghahreman A. The Synergistic Effect of Cu2+ Fe2+ Fe3+ Acidic System on the Oxidation Kinetics of Ag-Doped Pyrite. Journal of Physical Chemistry C, vol. 122(47), 2018, pp. 26897−26909. DOI: 10.1021/acs.jpcc.8b06727.

27. Schaible M. J., Pinto H. P., McKee A. D., Leszczynski J., Orlando T. M. Characterization and simulation of natural pyrite surfaces: A combined experimental and theoretical study. The Journal of Physical Chemistry C, vol. 123, 2019, pp. 26397−26405. DOI: 10.1021/acs.jpcc.9b07586.

28. Stojanov L., Vasilevski H., Makreski P., Jovanovski G., Mirceski V. Voltammetry of Solid Microparticles of Some Common Iron and Copper-Iron Sulfide Minerals. International Journal of Electrochemical science, vol. 17, 2022, 220346. DOI: 10.20964/2022.03.46.