MIREA – Russian Technological University (Moscow, Russia):

Sandulyak A. V., Professor, Doctor of Engineering Sciences, a.sandulyak@mail.ru
Tkachenko R. Yu., Postgraduate, tryu@yandex.ru
Sandulyak A. A., Professor, Doctor of Engineering Sciences, Professor, anna.sandulyak@mail.ru

Moscow Polytechnical University (Moscow, Russia):

Ershova V. A., Assosiate Professor, Candidate of Engineering Sciences, v.ershova@mail.ru

It has been noted that the information on magnetic properties of specific magnets available in the design and operation of magnetic separators/analyzers using magnetic fillers in the form of balls as the working body (polygradient type) is extremely limited, especially for magnets with varying sphericity coefficients (mutual ratios of characteristic sizes). Experiments using cylindrical samples (porous) as a ferromagnetic matrix rendered the induction data subsequently applied to establish the magnetic permeability, susceptibility, and magnetization values for the samples at various values of the length-todiameter ratio of φ = 1–16. The demagnetizing factor N was obtained and analyzed for the «short» samples (1 ≤ φ [φ]) in the range of magnetizing field strengths of 9–47 kA/m, taking into account the established transient value of φ = [φ] = 10–12 (when, at φ ≥ [φ], the magnetic properties of the sample correspond to the magnetic properties of its quasi-solid material). The analysis results for these data, required when assessing the actual magnetic properties of «short» working bodies, characteristic of polygradient magnetic separators/ analyzers, demonstrate the validity of the exponential dependence (decreasing with increasing ) of their demagnetizing factor.
The research was carried out with the financial support of the Ministry of Education and Science of the Russian Federation within the framework of the State Assignment in the field of science (project No. 0706-2020-0024) and of the Russian Foundation for Basic Research and the Royal Society of London under research project No. 20-52-10006.

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