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NOBLE METALS AND ITS ALLOYS
ArticleName The properties of electric double layer at activated carbon surface and their effect on gold and silver adsorption from cyanide solutions
DOI 10.17580/tsm.2022.11.02
ArticleAuthor Elshin V. V., Golodkov Yu. E.
ArticleAuthorData

Irkutsk National Research Technical University, Irkutsk, Russia:

V. V. Elshin, Professor, Head of the Department of Automation and Control, Doctor of Technical Sciences, e-mail: dean_zvf@istu.edu
Yu. E. Golodkov, Associate Professor at the Department of Automation and Control, Candidate of Technical Sciences, e-mail: yrg27@mail.ru

Abstract

This paper looks at the properties of electric double layer (EDL) found at the surface of activated carbons. The study relied on the electrical conductivity method, which is based on simultaneous use of polarization dependences at direct current and conductometric measurements at alternating current. It was found that the adsorption of gold and silver intensifies in the anode region of carbon surface polarization. Two regions with peak adsorption were identified in the following ranges of potentials: +0.2÷+0.25 and +0.6÷+0.8 V. EDL diffusion helps improve the environment for the adsorption of cyanide complexes of gold and silver by active centres of the adsorbent surface. The authors believe that an increased mass transfer in the first range of potentials can be attributed to a decreased diffusion resistance caused by changed zero charge polarity, while in the second range of potentials it can be attributed to the cyan-ion oxidation reaction and an easier access of the negatively charged cyanide complexes of gold and silver to the positively charged surface of the carbon adsorbent. The polarization dependences by direct current in the anode region tend to monotonously rise, which is indicative of a lower EDL density, an increased conductivity at the adsorbent surface/solution boundary and improved adsorption conditions. Graphs showing a relationship between alternating current and carbon adsorbent potential helped determine maximum conducti vity values, which almost match the peak values of gold and silver adsorption. The authors established that the adsorbent’s potential has a significant effect on the activated carbon adsorption of cyanide complexes of gold and silver. The use of the electrical conductivity method for examining the EDL helps explain certain features typical of the activated carbon adsorption of gold and silver from cyanide solutions.

keywords Adsorption, activated carbons, cyanide complexes of gold and silver, electric double layer
References

1. Efremova S. V., Kablanbekov A. A., Anarbekov K. K. et al. Coke fines based carbon adsorbent for gold recovery. Khimiya tverdogo topliva. 2019. No. 4. pp. 18–25. DOI: 10.1134/S0023117719040066.
2. Kishibaev K. K., Nechipurenko S. V., Tokpaev R. R. et al. Processing of waste carbon-mineral and vegetable raw materials of the Republic of Kazakhstan for gold recovery processes. Trudy Kolskogo nauchnogo tsentra RAN. 2018. Vol. 9, No. 2-2. pp. 842–847.
3. Kishibaev K. K., Tokpaev R. R, Atchabarova A. A. et al. Activated carbons of various origin in gold recovery processes. Zhurnal prikladnoy khimii. 2016. Vol. 89, Iss. 3. pp. 327–333.
4. Ibragimova R. I., Grebennikov S. F., Gurianov V. V. et al. The porous structure of activated carbon and its effect on the adsorption kinetics of gold(I) cyanide complex. Zhurnal fizicheskoy khimii. 2014. Vol. 88, No. 6. pp. 1052–1057. DOI: 10.7868/S0044453714060168.
5. Marsden J. O., House C. I. The chemistry of gold extraction. Littleton : Society For Mining, Metallurgy, and Exploration Inc. 2006. 651 p.
6. Streat M., Naden D. Ion exchange and sorption processes in hydrometallurgy. Chichester : John Wiley and Sons Inc, 1987. Vol. 19. p. 57.
7. Kasymova D. B., Edilkanova M. E., Mamyachenkov S. V., Sizikova N. V. Selective separation of gold and copper when processing copper-rich gold ore. Vestnik of D. Serikbaev EKTU. 2020. No. 4. pp. 40–47.
8. Dzhappuev R. K., Solgaev A. V., Zalevskaya K. N., Radchenko D. N. Recovery of gold from secondary raw material: UGC’s practices. Izvestiya Tulskogo gosudarstvennogo universiteta. Nauki o Zemle. 2020. No. 4. pp. 340–350.
9. Magomedov D. R., Koyzhanova A. K., Erdenova M. B., Abdyldaev N. N. Recovery of gold from sulphide ores and concentrates. Otechestvennaya geologiya. 2019. No. 5. pp. 85–92.
10. Bakhmatyuk B. P., Kurepa A. S. Electrochemical properties of activated charcoal in alkaline electrolyte. Elektrokhimicheskaya energetika. 2011. Vol. 11, No. 4. pp. 206–212.
11. Endo M., Takeda T., Kim Y. J., Koshiba K., Ishii K. High power electric double Layer capacitor (EDLC’s); from operating principle to pore size control in advanced activated carbons. Carbon Science. 2001. Vol. 1. pp. 117–128.
12. Shi H. Activated carbons and double layer capacitance. Electrochimica Acta. 1996. Vol. 41, Iss. 10. pp. 1633–1639. DOI: 10.1016/0013-4686(95)00416-5.
13. Koresh J., Soffer A. Double layer capacitance and charging rate of ultramicroporous carbon electrodes. Journal of The Electrochemical Society. 1977. Vol. 124, Iss. 9. pp. 1379–1385.
14. Zagudaeva N. M., Vilinskaya V. S., Tarasevich M. R., Steinberg G. V. Effect of the crystalline structure of carbon materials on their adsorption properties. Elektrokhimiya. 1981. Vol. 17, No. 3. pp. 467–469.
15. Zhen Kh. Ya., Yu A. M., Ma K. A. Characteristics of pores and their effect on the electrochemical capacity of activated carbons. Elektrokhimiya. 2012. Vol. 48, No. 12. pp. 1294–1302.
16. Vegter N. M., Sanderberg R. F., Botha A. J. Concentration profiles of gold inside activated carbon during adsorption. Journal of the Southern African Institute of Mining and Metallurgy. 1997. Vol. 97, Iss. 11-12. p. 299.
17. Frumkin A. N., Ponomarenko E. A., Burstein R. Kh. Chemisorption of oxygen and adsorption of electrolytes on activated carbon. Doklady Akademii Nauk SSSR. 1963. Vol. 149, No. 5. pp. 1123–1126.
18. Elshin V. V., Golodkov Yu. E. Examining the electric double layer during sorption of gold from thiocarbamide solutions on activated carbon. Vestnik Irkutskogo gosudarstvennogo tekhnicheskogo universiteta. 2020. Vol. 24, No. 6. pp. 1337–1346. DOI: 10.21285/1814-3520-2020-6-1337-1346.
19. Fomkin A. A., Tsivadze A. Yu., Shkolin A. V., Mukhin V. M., Dudarev V. I. Carbon adsorbents in the processes of cyanide recovery of gold. Protection of Metals and Physical Chemistry of Surfaces. 2014. Vol. 50, No. 6. pp. 563–567. DOI: 10.7868/S0044185614060035.
20. Elshin V. V., Golodkov Yu. E., Bogidaev S. A. The mechanics of gold and silver sorption with activated carbons: An electrochemical study. Tsvetnye Metally. 2005. No. 4. pp. 32–35.
21. Silver H. G. Chemical behavior of the components of the KCN/Kau(CN)2. Electroplating system. Journal of The Electrochemical Society. 1969. Vol. 116. p. 174.
22. Bobkov S. S., Smirnov S. K. Hydrocyanic acid. Moscow : Khimiya, 1970. 173 p.

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