Giproniсkel Institute LLC, St. Petersburg, Russia

I. V. Klimenko, Researcher, Nickel Refining Technologies Sector, Hydrometallurgy Laboratory, e-mail: KlimenkoIV@nornik.ru
M. B. Greyver, Head of the Nickel Refining Technologies Sector, Hydrometallurgy Laboratory, e-mail: GreyverMB@nornik.ru
M. I. Kalashnikova, Head of the Hydrometallurgy Laboratory, e-mail: KalashnicovaMI@nornik.ru
N. M. Vostrikova, Senior Researcher, Hydrometallurgy Laboratory, e-mail: VostricovaNM@nornik.ru

After the transition of the Nickel Electrolysis Shop of Kola MMC to the production of nickel cathodes by electrowinning, the flows and compositions of nickel solutions in cleaning operations, such as iron removal, changed significantly, which led to a number of problems. In this regard, large-scale work was previously carried out to optimize and select optimal modes of operation of the process stage while maintaining the existing equipment, which made it possible to establish its operation. However, Kola MMC is not going to stop there. The current focus of the enterprise on the production of premium grades of high-quality nickel products, as well as the change in the composition of the feedstock over time towards an increase in the iron content in it, leads to the need to look for ways of more effective and deep purification of nickel solutions from iron. Given the complexity of the process in real conditions (it is necessary not only to oxidize all the iron, but also to precipitate it into a cake with the minimum possible content of the valuable component, and often this factor can have a positive effect on the first process, but a negative effect on the second one, or vice versa), the desire of the enterprise to reduce capital costs contributes to the search for the most effective and scientifically sound technical solutions and process modes within the existing equipment. As a result, work was started on modeling the iron removal process of nickel chloride purification solutions in order to find further ways to increase the productivity of the iron removal stage. The article presents some results of studies carried out within the framework of this work, and also describes the methodology for conducting laboratory experiments, determines the required mixing power of the solution to achieve the kinetic mode, the order of the iron(II) oxidation reaction with respect to oxygen and iron, the values of the rate constant of iron(II) oxidation and the activation energy as applied to concentrated nickel chloride solutions with the presence of copper.

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