Nosov Magnitogorsk State Technical University (Magnitogorsk, Russia):

Orekhova N. N., Professor, Doctor of Engineering Sciences, Associate Professor, n_orehova@mail.ru
Fadeeva N. V., Associate Professor, Candidate of Engineering Sciences, Associate Professor, natali_fadeeva@mail.ru
Efimova Yu. Yu., Associate Professor, Candidate of Engineering Sciences, jefimova78@mail.ru

Melnikov Institute of Problems of Integrated Development of Mineral Resources of the RAS (Moscow, Russia):

Kolodezhnaya E. V., Leading Researcher, Candidate of Engineering Sciences, kev@uralomega.ru

Cast iron cooling generates iron-graphite flakes that may serve as a source of flaked graphite, a valuable material, in high demand by Russian manufacturers. This study was aimed at analyzing the changes in the dispersed composition and shape of iron-graphite flake dust particles when ground under various conditions. The grinding equipment comprised ball mills with metal and porcelain grinding media and a centrifugal impact grinding unit (a vertical shaft mill) with dynamic particle classification. The sieve analysis method and a laser particle size analyzer were used to study dispersion of the initial dust and its grinding products. The material composition and changes in the shapes of flake particles were studied using optical geometry analysis methods and scanning electron microscopy (SEM). Varying distributions of particles by size classes and grain agglomeration probability rates have been established for different grinding methods. The influence of the grinding method on the redistribution of magnetic particles is shown. It has been established that centrifugal milling of graphite flakes intensifies particle aggregation, but also contributes to higher performance in flotation separation as compared to ball milling. The following has been observed for centrifugal milling vs. ball milling: an increase in the yield by 3 %; higher mass fractions of carbon in fine and coarse product flotation concentrates by 22.7 and 17.5 %, respectively; and a 5 times lower concentration of the magnetic fraction.
The work was carried out with the financial support of the Russian Science Foundation as part of a grant for fundamental scientific and exploratory research in 2022–2023, agreement No. 22-27-20068, and with the participation of the TsKL NII «Nanostali» of the NMSU.

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