Saint-Petersburg Mining University, Saint Petersburg, Russia:

G. V. Petrov, Professor, e-mail: petroffg@yandex.ru
S. B. Fokina, Associate Professor, e-mail: fokina_sb@mail.ru
T. Yu. Nikitina, Post-Graduate Student, e-mail: nikatatka@yandex.ru

Hydrometallurgical processes for nickel converter matte refining are characterized by the distribution of platinum group metals between the liquid and solid phases. Chlorine refining technology for converter matte consists of oxidation leaching in chloride media and subsequent extraction of nickel from hydrochloric acid solutions. However, during the leaching stage, along with nickel, the transition of platinum group metals in the form of chloride complexes into the solution is possible. The kinetic inertness of iridium complexes makes it difficult to extract iridium from multicomponent solutions. This work includes study of iridium extraction from chloride solutions by reduction methods. The regularities of iridium extraction by cementation method using different metals as cementing agents were revealed, the effect of sulfur-containing precipitators addition is shown.

1. Tsemekhman L. Sh., Paretskiy V. M. Modern Processing Techniques for Copper-Nickel Sulphide Concentrates: a Review. Tsvetnye Metally. 2020. No. 1. pp. 24–32. DOI: 10.17580/tsm.2020.01.04.
2. Konovalov G. V., Kosovtseva T. R., Sizyakov V. M. Pyrometallurgical Processing of Sulfide Polymetallic Raw Stuff in Autogeneous Forced Mode. Journal of Industrial Pollution Control. 2017. Vol. 33, Iss. 1. pp. 898–904.
3. Khainasova T. S. Factors Affecting Bacterial and Chemical Processes of Sulphide Ores Processing. Journal of Mining Institute. 2019. Vol. 235, Iss. 1. pp. 47–54.
4. Aleksandrova T. N., Nikolaeva N. V., Lvov V. V., Romashev A. O. Ore Processing Efficiency Improvements for
Precious Metals Based on Process Simulations. Obogashchenie Rud. 2019. No. 2. pp. 8–13. DOI: 10.17580/or.2019.02.02.
5. Bulaev A., Melamud V., Boduen A. Two-Stage Agitation Leaching of Old Flotation Tailings. Solid State Phenomena. 2019. Vol. 298. pp. 116–120.
6. Crundwell F. K., Moats M. S., Ramachandran V., Robinson T. G., Davenport W. G. Extractive Metallurgy of Nickel, Cobalt and Platinum Group Metals. Oxford, Elsevier, 2011. 622 p.
7. Nelson L. R., Georgalli G. A., Hines K. L., Hundermark R. J. Converter Processing of Platinum Group Metals. Mineral Processing and Extractive Metallurgy: Transactions of the Institute of Mining and Metallurgy. 2019. Vol. 128, Iss. 1-2. pp. 134–159.
8. Eksteen J. J., Schalkwyk van R. F., Akdogan G. Leaching of Ni – Cu – Fe – S Converter Matte at Varying Iron Endpoints; Mineralogical Changes and Behavior of Ir, Rh and Ru. Hydrometallurgy. 2013. Vol. 136. pp. 36–45.
9. Fedoseev I. V., Barkan M. Sh. Improvement of Hydrometallurgical processing of sulfide copper-nickel middlings. Tsvetnye Metally. 2016. No. 5. pp. 27–32. DOI: 10.17580/tsm.2016.05.04.
10. Stensholt E. O., Zachariasen H., Lund J. H. Falconbridge chlorine leach process. Transactions of the Institution of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy. 1986. Vol. 95. pp. 10–16.

11. Kobayashi H., Shoji H., Asano S., Imamura M. Chlorine Leaching of Nickel and Cobalt Mixed Sulfide Using Iron Chloride Solution. Journal of the Japan Institute of Metals. 2017. Vol. 81, Iss. 5. pp. 282–287.
12. Aleksandrova T. N., O’Connor C. Processing of Platinum Group Metal Ores in Russia and South Africa: Current State and Prospects. Journal of Mining Institute. 2020. Vol. 244. pp. 462–473.
13. Mrozik M., Müller U., Heide G., Talovina I. V., Duryagina A. M. Mineralogical Composition of Nickelhydrosilicate Ores at the Elov Deposit (The Northern Central Urals). Innovation-Based Development of the Mineral Resources Sector: Proceedings Of The XI^th Russian-German Raw Materials Conference, Potsdam, Germany, 7–8 November 2018. pp. 103–114.
14. Naftal’ M. N., Kuznetsov N. S., Naboichenko S. S., Solntsev K. A. Development of the Nickel-Refining Production at Norilsk Nickel Harjavalta Oy in GMK Norilsk Nickel. Russian Metallurgy (Metally). 2019. Iss. 5. pp. 495–506.
15. Livingstone S. E. The Chemistry of Ruthenium, Rhodium, Palladium, Osmium, Iridium and Platinum. Oxford, Pergamon Press. 1975. 208 p.
16. Le M. N., Lee M. S. Separation of Iridium(IV) and Rhodium(III) from Hydrochloric Acid Solution by Solvent Extraction with Cyanex 921. Geosystem Engineering. 2018. Vol. 21, Iss. 4. pp. 210–216.
17. Nikoloski A. N., Ang K. L., Li D. Recovery of Platinum and Rhodium from Acidic Chloride Leach Solution Using Ion Exchange Resins. Hydrometallurgy. 2015. Vol. 152. pp. 20–32.
18. Cheremisina O., Sergeev V., Ponomareva M., Ilina A., Fedorov A. Kinetics Study of Solvent and Solid-Phase Extraction of Rare Earth Metals with Di-2-Ethylhexylphosphoric Acid. Metals. 2020. Vol. 10, Iss. 5. pp. 1–15.
19. Nguyen T. H., Sonu C. H., Lee M. S. Separation of Pt(IV), Pd(II), Rh(III) and Ir(IV) from Concentrated Hydrochloric Acid Solutions by Solvent Extraction. Hydrometallurgy. 2016. Vol. 164. pp. 71–77.
20. Bulatov M. I., Kalinkin I. P. Practical Manual of Photocolorymetric and Spectrophotometric Methods Analysis. 4^th ed., rev. and exp. Leningrad: Chemistry, 1976. 376 p.