LLC Gipronickel Institute, Saint Petersburg, Russia

А. Yu. Chetverkin, Senior Researcher of the Laboratory for Finished Products, e-mail: ChetverkinAYu@nornik.ru
А. Yu. Pavlov, Leading Engineer of the Laboratory for Finished Products
Т. V. Vergizovа, Leading Researcher of the Laboratory of New Materials

JSC Kola MMC, Monchegorsk, Russia
V. L. Dubrovsky, Chief Specialist of the Department of Scientific and Technical Development

Matte chlorine dissolution processes are successfully used in world practice. Currently, the metallized phase, which concentrates the bulk of precious metals, is isolated from particularly precious metal-rich converter mattes, practically only for the purpose of its separate processing. The current technologies for processing the metallized phase are based on multi-stage sulfuric acid leaching to extract non-ferrous metals and iron into a solution, oxidize sulfur and obtain a concentrate rich in precious metals. The improvement of production at the Kola Mining and Metallurgical Company is associated with the possibility to separate and by using chlorine technology separately process the metallized magnetic fraction from copper-nickel converter matte, which concentrates the vast majority of the precious metals contained in it. Technological schemes of refining in chloride media are effective under the condition of high total recovery both in the main conversion of non-ferrous metals (dissolution – purification of solution – electrodeposition) and precious metals during the processing of the chlorine dissolution residue, which concentrates them. In the course of research, when varying the parameters of the chlorine dissolution process of the magnetic fraction (redox potential (RP), process duration, and chloride ion concentration), the effect of sulfur content in the magnetic fraction on the recovery of non-ferrous metals, iron, and precious metals into solution has been determined. It has been established that the main transition of precious metals into solution occurs during dissolution of the material metallic phase. It is shown that deep recovery of non-ferrous metals into solution and minimal losses of precious metals occur during the chlorine dissolution at the lower RP value in the first stage with the dissolution of the metallized part of the magnetic fraction and an increase in the RP value in the second stage to dissolve the sulfide components. The change in the sulfur content in the magnetic fraction, the RP value and the duration of the chlorine dissolution affects the yield of the chlorine dissolution residue and the method of removing elemental sulfur to obtain precious metals concentrate and does not significantly affect the degree of oxidation of sulfide sulfur of the magnetic fraction to sulfate.

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