Institute Gipronikel LLC, Saint Petersburg, Russia:

A. Yu. Chetverkin, Researcher at the Hydrometallurgy Laboratory, e-mail: Chetverkin@nornik.ru

T. V. Vergizova, Lead Researcher at the Hydrometallurgy Laboratory, Candidate of Chemical Sciences

Kola Mining and Metallurgical Company JSC, Monchegorsk, Russia:
О. А. Khomchenko, Chief Specialist of Science and Technology Development Department, Engineering Center, Candidate of Technical Sciences
V. L. Dubrovskiy, Head of Science and Technology Development Department, Engineering Center

Development of the refining facility of Kola Mining and Metallurgical Company is related to separation of magnetic fraction from copper-nickel matte and its processing. The magnetic fraction houses the major part of platinum group metals contained in the matte. A laboratory study helped understand how the chlorine dissolution parameters — i. e. the oxidation-reduction potential and the process duration — influence the solution extraction of non-ferrous and precious metals, iron and sulphur. It was found that the initial dissolution rate was quite high (up to 0.7 g/(g·min)), which is indicative of the metal phase of the material transfering in the solution. It was established that a longer process duration is associated with a higher oxidation degree of sulphide sulphur and its transition into solution in the form of sulphates leading to acid formation. It is shown that within the entire range of chlorination parameters a poor transition of metals into solution is observed, %: <0.07–0.1 Pd; <0.1 Pt; <0.1–2.7 Au. And a significant portion of the precious metals that transfered into the solution during chlorine dissolution of magnetic fraction is extracted into cement copper when copper is removed from the solution. When nickel powder is used for solution purification, the residual concentration of copper is 0.6 g/l, and when iron powder is used, it is from 0.03 to 0.05 g/l. The paper analyses some effective techniques for removing elemental sulphur from the chlorination deposit. The authors note that there is a relationship between the non-ferrous metals extraction level and the choice of technique for further sulphur removal. According to the authors, a sustainable technique (in terms of chlorine) could potentially be developed for producing high-purity cathode nickel and commercial salts.

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