Capture effect of dry magnetic separator on biotite in fine aggregates: Experimental results and numerical simulations

Abstract

In this paper, a series of magnetic separation experiments and FEM-DEM simulations were carried to study the dynamic capture behavior of a dry magnetic separator (DMS) for biotite in fine aggregates. Experimental results show that the capture effect of a DMS on biotite in fine aggregates is greatly affected by the particle size. Coarse particles (2 mm–4.75 mm) and ultrafine particles (0–0.075 mm) are difficult to be captured by the DMS, while fine particles (0.075 mm–2 mm) are easy to be captured. Numerical simulations show that the effect of a DMS on the captured morphology of biotite in fine aggregates comes from the arrangement of magnetic system structure. Compared with magnetic induction, the magnetic induction gradient produced by the extruded magnetic system has a more profound effect on the capture process of biotite. Based on the comprehensive analysis results of experiment and simulation, we conclude that the capture mechanism of DMS on biotite can be divided into four processes: magnetization, extrusion, entraining and separation. This study provides a theoretical basis for evaluating the effectiveness of DMS in sorting biotite from fine aggregates and designing high-performance DMS. • Capture mechanism of biotite by DMS was revealed through experiments and simulations. • A coupled FEM-DEM simulation program is developed. • Captured morphology of DMS on biotite in fine aggregates was demonstrated.