Reverse flotation separation of hematite from quartz assisted with magnetic seeding aggregation

Abstract

In this work, fine magnetite was used as a magnetic seed to enhance the separation efficiency of fine hematite from quartz during reverse micro-flotation. Gradual increases in hematite recovery and iron grade were accomplished with increasing magnetite content, whereas the iron content in quartz reject decreased. Particle size analysis, sedimentation tests, and scanning electron microscopy analysis of hematite from the separation process confirmed aggregation of hematite with magnetite particles. The measurements of magnetic susceptibility of product and reject indicate predominant aggregation of magnetite with hematite, and only marginal with quartz. Zeta-potential analysis and colloidal force analysis confirmed attractive interactions between magnetite and hematite, and repulsive between magnetite and quartz. Therefore, fine hematite aggregation with magnetite particles reduces coating of quartz with fine hematite, benefiting the flotation purification of fine hematite from quartz in terms of both recovery and grade.