MMC Norilsk Nickel Polar Division, Norilsk, Russia

D. D. Novikova, Chief Specialist of the Laboratory of Engineering Support for the Production of the Copper Plant, Сеnter for Engineering Support of Production, e-mail: NovikovaDD@nornik.ru
О. V. Bolshakova, Head of the Laboratory of Engineering Support for the Production of the Copper Plant, Сеnter for Engineering Support of Production, e-mail: BolshakovaOV@nornik.ru
D. А. Arbuzov, Chief Engineer of the Copper Plant, e-mail: ArbuzovDA@nornik.ru
М. V. Glibovets, Chief Engineer of the PJSC MMC Norilsk Nickel, Director of the Production Support Directorate, e-mail: GlibovetsMV@nornik.ru

One of the ways to increase the efficiency of copper refining production is to increase the cathode current density. Operation at high current densities (300 A/m2 or more) allows for increased conversion productivity. However, intensive process management has a negative effect on the appearance of cathode products and leads to the formation of defects on the surface of the cathode web (dendrites and rounded growths). In addition, the presence of these defects significantly increases the risks of increasing the content of impurity components in the cathode metal, due to the loose dendritic structure of the cathode, in which electrolyte residues can accumulate. A technical solution is proposed that makes it possible to stabilize the regular appearance of copper cathodes when operating at high current densities by optimizing the consumption of special colloidal additives and the composition of the electrolyte used. As a result of previous studies, it was found that the preservation of quality indicators at current densities up to 340 A/m² can be achieved with the following electrolyte composition, g/dm³: 53–55 Cu; 160–170 H₂SO₄; 20–24 Ni; 0.050 Cl^–. To select the optimal flow rate of colloidal additives, laboratory studies were carried out in the current density range of 300–340 A/m² and the following flow rates of colloidal additives, g/t: 80–110 of hide glue; 65–80 of thiourea; 50–60 of thiourea, pre-soaked in a copper electrolyte at a temperature of 50–60 ^oC for 24 hours. The optimal consumption of colloidal additives for each of the studied current densities is presented, ensuring a minimum number of surface defects and an optimal content of impurities in copper cathodes.
The authors express special gratitude for their participation in the work to the head of the copper electrolysis workshop of the Copper Plant of the Polar Branch, S. O. Tyulenev, and the head of the technical department of the Copper Plant of the Polar Branch, K. E. Voronin.

1. Krupnov L. V., Tsymbulov L. B., Malakhov P. V., Ozerov S. S. Operation of autogenous smelters at Nornickel’s Polar Division when processing raw materials with low energy potential. Tsvetnye Metally. 2022. No. 2. pp. 40–48.
2. Krupnov L. V., Malakhov P. V., Ozerov S. S., Midyukov D. O. Justification of the choice of technology for processing low-energy raw materials. Metallurgy of non-ferrous, rare and precious metals : Proceedings of the XV International Conference named after Corresponding Member of the Russian Academy of Sciences Gennady Leonidovich Pashkov, Krasnoyarsk, September 06–08, 2022. Krasnoyarsk : Nauchno-innovatsionniу tsentr, 2022. pp. 237–242.
3. Krupnov L. V., Rumyantsev D. V., Popov V. A. et al. Technical solutions to improve the operating conditions of Vanyukov furnaces for processing man-made raw materials. Metallurg. 2024. No. 4. pp. 106–111. DOI: 10.52351/00260827_2024_4_106
4. Krupnov L. V., Pakhomov R. A., Kaverzin A. V. et al. Study of the properties of the intermediate layer of Vanyukov furnaces in the processing of copper-nickel-containing raw materials. Non-ferrous metals and Minerals-2024 : Proceedings of the Twelfth International Congress, Krasnoyarsk, September 09–13, 2024. Krasnoyarsk : Nauchno-innovatsionniу tsentr, 2024. pp. 883–888.
5. Salimzhanova E. V., Devochkin A. I., Yudin E. V., Karpushova D. D. Development and indtroduction of technical solutions to bring the quality of polar division cathode copper to conformity with London Metal Exchange standard. Tsvetnye Metally. 2018. No. 8. pp. 44–51.
6. Novikova D. D., Shulga E. V., Rendov A. S., Novoseltsev V. A. Effect of various factors on the physicochemical properties of cathodes du ring copper electrorefining. Tsvetnye Metally. 2022. No. 2. pp. 58–63.
7. Novikova D. D., Bolshakova O. V., Yurev A. I., Shekhanov R. F. Selection of the optimal electrolyte composition and consumption of colloidal additives when operating at high current densities. XII International Scientific Conference Modern Methods in Theoretical and Experimental Electrochemistry : Proceedings. Ples, Russia, 2021. p. 54.
8. Volkhin A. I., Eliseev E. I., Zhukov V. P., Smirnov B. N. Anodic and cathode copper : Physico-chemical and technological bases. Chelyabinsk, 2001. 430 p.
9. Volkov L. V., Kalashnikova M. I., Solovev E. M. Analysis of principal components for determination of cathode copper quality indices, which make an influence on spiral elongation number. Tsvetnye Metally. 2014. No. 4. pp. 56–61.
10. Devochkin A. I., Kuzmina I. S., Salimzhanova E. V., Petukhova L. I. The study of sulfate copper electrolyte physico-chemical properties depending on its components and temperature. Tsvetnye Metally. 2015. No. 6. pp. 67–70.
11. Kuzmina I. S. et al. Effect of composition and temperature on the viscosity of copper-nickel sulfuric acid solutions of the copper electrorefining process. Khimicheskaya tekhnologiya. 2015. Vol. 16, No 8. pp. 448–451.
12. Krasikov Yu. S., Astakhova R. К., Belenkiy А. B., Yermakov S. S. et al. Application of surfactants in copper electrodeposition processes. Leningrad : AN SSSR, 1987. 30 p.
13. Nevárez-Llamas E. D., Araneda-Hernández E. A., Parra-Sánchez V. R., Villagrán-Guerra E. A. Effect of glue, thiourea, and chloride on the electrochemical reduction in CuSO4–H2SO4 solutions. Metals. 2023. Vol. 13. 891.
14. Muhlare T. A., Groot D. R. The effect of electrolyte additives on cathode surface quality during copper electrorefining. The Journal of The Southern African Institute of Mining and Metallurgy. 2011. Vol. 111. pp. 371–379.
15. Mohadesi A., Roohparvar R., Yaghoobi N. Thiourea as an additive in copper electrorefining process. Iranian Journal of Analytical Chemistry. 2024. Vol. 10, Iss. 2. pp. 154–164.
16. Kang M. S., Kim S. K., Kim K., Kim J. J. The influence of thiourea on copper electrodeposition: adsorbate identification and effect on electrochemical nucleation. Thin Solid Film. 2008. Vol. 516. pp. 3761–3766.
17. Mori K., Yamakawa Y., Oue S., Taninouchi Y. et al. Effect of impurity ions and additives in solution of copper electrorefining on the passivation behavior of low-grade copper anode. Mater. Trans. 2023. Vol. 64. 242.
18. Collet T., Wouters B., Hallemans N., Ramharter K. et al. The timevarying effect of thiourea on the copper electroplating process with industrial copper concentrations. Electrochimica Acta. 2023. Vol. 437. 141412.
19. Khayatzadeh H., Tahmasbi K. Optimizing electrolyte conditions for the elimination of nodules in copper electrorefining process. JOM. 2024. Vol. 76. 452.
20. Pourgharibshahi M., Khorasani S. M. J., Yaghoobi N., Lambert P. A descriptive model for twin-textured growth and nodulation of copper cathodes. Electrocatalysis. 2023. Vol. 14. 138.
21. GOST 859–2014. Copper. Grades. Introduced: 01.03.2002.