Adjustment of electrode processes to build up contrast processing characteristics of sulfides

The article describes the studies into generation of contrast electrochemical characteristics of sulfides during oxidation–reduction processes in milling cycle with the pyrite– iron micro galvanic coupling and with monitoring and adjustment of electrode processes. The oxidation and oxygen absorption kinetics of pyrite in milling is studied, and the concentration of sulfur-containing anions in oxidation of pyrite in the pH range of 6–14 is presented. It is found that the highest absorption of oxygen by pyrite takes place in the high-alkali environment (pH 12). With the increasing alkalinity of the medium, the concentration of sulfur-containing anions grows by a few factors, and this is true particularly for thiosulfate ions (S2O3 2–) where floatability of pyrite decreases. The experimental measurements of electrode potentials of pyrite and steel electrodes reveal correlation between the processing conditions, values of electrode potentials and floatability of sulfides and quartz. The values of the potentials depend on the pH and on the concentration of modifiers. The largest difference between the potentials happens at pH 11 and is 600 mV as against the values of the potentials at pH 7 and 9, which governs pyrite suppression and affects selective flotation. The influence of the metallic iron powder as the milling environment on the floatability of sulfide minerals (FeS2, CuFeS2, ZnS) and SiO2 in the presence of different modifiers at pH 7 and 11. The long-time milling (> 60 min) induces intense oxidation of sulfide minerals and milling iron (>2 kg/t), which activates flotation of pyrite and reduces quality of concentrates. With the increasing concentrate of sodium sulfate, the pyrite electrode potential grows in the negative range at рН ≥ 9–11, which goes with the reduction in pyrite extraction.

Bocharov V. А., Ignatkina V. A., Abrytin D. V., Kayumov А. А., Kayumova V. R. (Korzh). Adjustment of electrode processes to build up contrast processing characteristics of sulfides. MIAB. Mining Inf. Anal. Bull. 2022;(10):39-50. [In Russ]. DOI: 10.25018/ 0236_1493_2022_10_0_39.

The study was supported by the Russian Foundation for Basic Research, Project No. 20-05-00157.

V.A. Bocharov¹, Dr. Sci. (Eng.), Professor, e-mail: adminopr@misis.ru, ORCID ID: 0000-0002-8233-9635,
V. A. Ignatkina¹, Dr. Sci. (Eng.), Professor, e-mail: woda@mail.ru, ORCID ID: 0000-0003-2552-206X
D.V. Abrytin, Cand. Sci. (Eng.), Deputy General Director, OOO «ADV-Inzhiniring», e-mail: abrutin@mail.ru,
A.A. Kayumov¹, Cand. Sci. (Eng.), Senior Process Engineering, e-mail: maliaby_92@mail.ru, ORCID ID: 0000-0003-0502-6595,
V.R. Kayumova (Korzh)¹, Graduate Student, e-mail: viktoriya.korzh09@gmail.com, ORCID ID: 0000-0001-7527-1284,
¹ National University of Science and Technology «MISiS», 119049, Moscow, Russia.

A.A. Kayumov, e-mail: maliaby_92@mail.ru.

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