Kola MMC, Monchegorsk, Russia:

M. I. Ryabushkin, First Deputy General Director — Chief Engineer, e-mail: RyabushkinMI1@kolagmk.ru

Gipronikel Institute LLC, Saint Petersburg, Russia:
A. L. Romanov, Principal Specialist at the Laboratory for Geological Studies
R. A. Pakhomov, Senior Researcher at the Pyrometallurgy Laboratory, Candidate of Technical Sciences, e-mail: pakhomovra@nornik.ru
L. B. Tsymbulov, Director of the Research and Development Department, Doctor of Technical Sciences

Kola Mining and Metallurgical Company has recently introduced significant changes into its processing circuits that deal with sulphide nickel concentrates, the product of converter matte separation. They help reduce both losses and operating costs, as well as generate extra revenues due to enhanced product quality. At the same time, the upgrades done to the production equipment and the adoption of electrowinning process for obtaining high-grade nickel cathodes at Norilsk Nickel sites require that the tube kiln nickel powder, which is subjected to chlorine dissolution at Kola MMC’s electrowinning plant, was of particular quality. The key quality requirements concerning the tube kiln nickel powder include the presence of carbon component and slag-forming impurities (SiO₂, Al₂O₃ and others), which impact the performance of the followinghydrom tallurgical process stage, as well as the metal content of the resulting middlings. Due to additional conditions set, concentration techniques should be used to enhance the quality of the middlings. The drawbacks of the existing magnetic separation line, as well as the peculiar behaviour of the raw materials that revealed itself during the start-up, made the line upgrade necessary. This paper examines certain production flowsheets and looks at improving the quality of the final product by separating materials based on their differing magnetic properties.

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