Recovery of Microcrystalline Graphite from Quartz Using Magnetic Seeding

Abstract

Efficient beneficiation of microcrystalline graphite remains a challenge. Selective recovery of microcrystalline graphite from quartz using hydrophobized magnetite as magnetic seed is studied in this work. Magnetite was hydrophobized by the surface coating of sodium oleate. The hydrophobic agglomerates were then separated by magnetic separation. Sedimentation experiments were performed to study the adhesion of microcrystalline graphite and quartz to magnetite particles. The results showed that hydrophobized magnetite led to a higher microcrystalline graphite recovery than that of the original magnetite, due to the higher probability to bond with microcrystalline graphite. However, the hydrophobization of the magnetite surface had an insignificant effect on its interaction with quartz. The force analysis based on the extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory indicated that the total attractive interaction between hydrophobized magnetite and microcrystalline graphite were obviously stronger than that between hydrophobized magnetite and quartz, resulting in the selective aggregation between hydrophobized magnetite and microcrystalline graphite.