Surface Modification of Pentlandite and Serpentine with Reagents and Magnetite for Magnetic Separation

Abstract

In this study, selective magnetic coating was employed to separate pentlandite and serpentine. The surface properties of minerals with and without reagents and magnetite were characterized by zeta potential measurements, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Zeta potentials showed that the surfaces of serpentine and magnetite were both negatively charged with the addition of sodium hexametaphosphate. Thus, serpentine was hardly coated by magnetite due to the electrostatic repulsion between them. The results of SEM and FTIR demonstrated that a magnetic coating of magnetite was observed on the pentlandite rather than on the serpentine. The VSM measurements confirmed that the magnetism of pentlandite was increased significantly due to the selective adsorption of magnetite on its surfaces; therefore, pentlandite was successfully separated from serpentine by magnetic separation. The study shows that selective magnetic coating technology has the alternative potential to separate pentlandite from serpentine.