National University of Science and Technology MISIS (Russia, Moscow)

K. B. Dyusenbekov, Postgraduate Student, 20line@mail.ru
D. V. Shekhirev, Cand. Eng., Associate Prof., Senior Researcher, shekhirev@list.ru
Yu. V. Konyukhov, Dr. Eng., Prof., Head of the Dept., ykonukhov@misis.ru
D. V. Zinoveev, Cand. Eng., Associate Prof., zinoveev.dv@misis.ru
D. S. Suvorov, Assistant Prof., suvorov.ds@misis.ru

State Scientific Center of the Russian Federation “I. P. Bardin TsNIIChermet” (Russia, Moscow)
A. I. Volkov, Cand. Chem.

The results of an experimental study of a combined ferromanganese ore beneficiation process are presented. This process includes gravity concentration using jigging, low-temperature magnetizing roasting of gravity concentrates in a hydrogen atmosphere, and stepwise magnetic separation of the roasted product. The mineral composition of the feedstock ore includes hematite, manganese minerals such as hausmannite, braunite, and rhodonite, and nonmetallic minerals such as quartz, calcite, kaolinite, and albite. Jigging by size classes of -2.5+1.0 mm (coarse class) and -1.0+0.5 mm (fine class) ensured the production of gravity concentrates with a Mn content of 31.81 % and 28.72 %, Fe – 20.25 % and 20.48 %, with extractions of Mn of 80.59 % and 76.37 % and Fe of 90.81 % and 85.39 %, respectively. Magnetizing roasting was carried out in a hydrogen environment at 350 °C for 30 and 60 min, after which the roasted products were subjected to stepwise magnetic separation in fields with induction of 0.1; 0.2 and 0.6 T. Increasing the roasting time from 30 to 60 minutes resulted in an increase in the Mn content in the non-magnetic fraction to 46.80% (for the coarse grade) while reducing the Fe content to 0.73%, corresponding to a Mn/Fe ratio of 64.38. The target process parameters — Mn content ≥ 36% and Mn/Fe ratio ≥ 7 in manganese concentrate—as well as the production of iron concentrate as a standalone commercial product, were achieved in all experiments. X-ray phase analysis confirmed the selective conversion of hematite to magnetite while maintaining the structure of the manganese minerals. Replacing carbon-containing reducing agents with hydrogen significantly reduces energy consumption and eliminates direct CO₂ emissions.

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