Federal State Budgetary Institution of Science Baikal Institute of Nature Management Siberian Branch of the Russian Academy of Sciences (BINM SB RAS), Ulan-Ude, Russia

I. G. Antropova, Head of the Laboratory of Chemistry and Technology of Natural Raw Materials, Candidate of Technical Sciences, e-mail: inan@bimn.ru
P. А. Gulyashinov, Researcher of the Laboratory of Chemistry and Technology of Natural Raw Materials, Candidate of Technical Sciences А. D. Budaeva, Leading Engineer of the Laboratory of Chemistry and Technology of Natural Raw Materials
I. P. Dashiev, Engineer of the Laboratory of Chemistry and Technology of Natural Raw Materials
D. P. Khomoksonova, Junior Researcher of the Laboratory of Chemistry and Technology of Natural Raw Materials
P. L. Paleev, Researcher of the Laboratory of Chemistry and Technology of Natural Raw Materials, Candidate of Technical Sciences

Oxidized and mixed ores of heavy non-ferrous metals are complex raw materials for flotation processing. In most cases, during the development of polymetallic ores, they are left in open areas and/or classified as unpayable and, if the lower level of sulfide ores is unprofitable for mining, they are left in the depths. Nevertheless, these ores are an important source of lead, zinc, copper and other non-ferrous metals, which makes their processing an urgent task. Combined methods have been developed for the enrichment of oxidized lead-zinc ores from Buryatia deposits, including sulfidizing roasting of ores using pyrite-containing industrial products as a sulfidizer. These technologies significantly enhance the extraction of valuable metals. Sulfidizing roasting at the stage of preparation of oxidized ores for flotation makes it possible to develop and activate complex mineral complexes. It has been established that upon joint roasting of a mixture of oxidized and pyrite-containing lead-zinc ores (sulfidizer) at a mass ratio of 2:(0.25–0.40) and a temperature of 650–700 ^оC, selective oxidation of pyrite occurs, accompanied by the disintegration of intergrowth lead and zinc sulfides and deep sulfidation of all oxidized Pb and Zn minerals. Adding a small dosage of calcium oxide to the charge effectively binds the released sulfur dioxide converting it into CaSO₄ anhydrite in a cinder. Based on the data of the cinder analysis, it was found that the main roasting products, along with relict sulfide minerals of lead and zinc, are newly formed compounds such as ZnS, PbS, Fe₃O₄ and CaSO₄. Optimal conditions for sulfidizing roasting have been determined for each type of oxidized ores, which ensure the extraction of Pb at the level of 88–95%, Ag – 85–91%, Zn – 63–70%. These methods are applicable not only to the refractory ores of specific deposits but also to similar objects.
The research was conducted within the framework of the state assignment of the Baikal Institute of Nature Management SB RAS, project no. AAAAA-A21-121011890003-4, and using equipment from the CUC BINP SB RAS and GI SB RAS (Ulan-Ude).

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