Stable buildup of particles in a vibrating-pulsating high gradient magnetic separator: A simulation study

Vibrating-pulsating high gradient magnetic separation (VPHGMS) is a new technology developed from pulsating high gradient magnetic separation (PHGMS). It has higher selectivity than PHGMS due to the introduction of vibration into the matrix. However, previous research mainly focused on the separation performance of VPHGMS through experiments; few studies have concerned about its separation mechanism. In this study, a 2D simulation was applied to reveal the magnetic field distribution, flow field distribution, and particle buildup characteristics in a VPHGMS separator. It was found that the magnetic field distribution around the matrix did not change with the displacement of the matrix, but a much faster and stronger transformation of fluid velocity was observed in VPHGMS than in PHGMS. When the matrix was vibrating, some particles were able to follow its movement and occupied a stable buildup area in the upper and lower surfaces of the matrix. This area expanded with increasing magnetic field distribution, volume susceptibility, and diameter of particles, but shrank with increasing vibrating frequency. The selectivity of VPHGMS was also investigated by analyzing the separation performance on an idealized mixture of two minerals. The simulation results predicted a drop in recovery and an enhancement in selectivity under increased vibrating frequency, which was consistent with experimental results from former studies.