Enhancing the separation of refractory weakly magnetic minerals with magnetic fluid in high gradient magnetic separation: Conversion of competing capture to mechanical entrainment

Due to serious competing capture of magnetic gangue minerals in high gradient magnetic separation (HGMS), combined separation processes which commonly have defects of long flowsheets and high energy consumption are applied to processing refractory weakly magnetic ores. High gradient magnetic separation coupling with magnetic fluid (HGMSCMF) is proved effective in eliminating competing capture and presents great potential in recovering refractory magnetic minerals, but the enhancing mechanism and particle capture relations among magnetic valuable minerals, magnetic gangue minerals and nonmagnetic minerals still remains unclear. In this study, particle capture and separation behaviors of minerals with different magnetic characteristics in HGMS and HGMSCMF were comprehensively investigated through pure and artificial mixed ore experiments using ilmenite, augite and quartz. Captured mass of augite was quite low and could hardly increase with increasing applied induction while that of ilmenite maintained a high level and increased with increase of applied induction even under high MnCl2 concentration. Results of artificial mixed ore experiments and numerical simulation of particle capture presented that separation characteristics of ilmenite-augite mixed ore gradually approached to that of ilmenite-quartz mixed one, indicating the conversion of competing capture to mechanical entrainment for high selectivity in HGMSCMF.