RESEARCH OF MAGNETIC FIELD DISTRIBUTION IN THE WORKING AREA OF DISK SEPARATOR, TAKING INTO ACCOUNT AN INFLUENCE OF MATERIALS OF PERMANENT MAGNETS

Based on the results of a numerical-field analysis of the distribution of the magnetic force field in the working area of the disk magnetic separator, designed to clean bulk substances from ferromagnetic inclusions, the influence of the magnetic material of the poles of the magnetic system on the field distribution is determined. A consistent study of two magnetic systems assembled on the basis of magnetic materials of different classes is carried out. The finite element method implemented in the COMSOL Multiphysics software environment is used to calculate the distribution of magnetic induction in a disk magnetic separator with rare-earth and ferrite magnets. Due to the complexity of the spatial geometry of the force field in the working area of the disk magnetic separator, a three-dimensional model of the magnetic system is developed. A comparative analysis of the distribution of the magnetic force field in the working area of the disk separator with a highly coercive magnetic system and with a magnetic system based on ferrite blocks is carried out. As a result of the analysis, it is found that the indicators of the intensity and heterogeneity of the magnetic field for a highly coercive magnetic system significantly exceed the corresponding parameters of a ferrite magnetic system. It is proved that when choosing magnets for the magnetic system of a disk separator, preference should be given to highly coercive alloys, the magnetic properties of which significantly exceed the magnetic properties of ferrite magnets. To reduce the cost of the magnetic system of the disk separator, the use of a combined magnetic system assembled from magnetic materials of different classes is proposed. Studies of combined magnetic systems with various mass fractions of magnetic materials are done. The ratio of the mass fractions of magnets of various properties in the poles of the magnetic system is determined, at which sufficiently high magnetic characteristics are provided in the working area. It is shown that the presence of a ferrite fraction in the magnetic poles not only reduces the cost of the magnetic system of the separator, but also reduces the mass of the system. The tasks of further research are justified

Levitation forces of a bulk YBCO superconductor in gradient varying magnetic fields

The levitation forces of a bulk YBCO superconductor in gradient varying high and low magnetic fields generated from a superconducting magnet were investigated. The magnetic field intensity of the superconducting magnet was measured when the exciting current was 90 A. The magnetic field gradient and magnetic force field were both calculated. The YBCO bulk was cooled by liquid nitrogen in field-cooling (FC) and zero-field-cooling (ZFC) condition. The results showed that the levitation forces increased with increasing the magnetic field intensity. Moreover, the levitation forces were more dependent on magnetic field gradient and magnetic force field than magnetic field intensity.