Mechanistic insight of hydrophobic agglomeration of rhodochrosite fines Co-enhanced by Oleic-Kerosene emulsion and static magnetic field

Abstract

Efficient enrichment of fine rhodochrosite is key to purifying manganese carbonate ore and reducing the discharge of electrolytic manganese slag at the source. Enhancing the agglomeration of rhodochrosite fines is important for efficient flotation separation. In this study, we investigated the agglomeration mechanism of rhodochrosite fines co-enhanced by oleic-kerosene emulsion and static magnetic field using agglomerate and surface properties analysis, electrical conductivity and atomic force microscopy measurements, and extended Derjaguin, Landau, Verwey, and Overbeek theoretical calculations. The results showed that the agglomerate size and regularity degree increased with increasing shearing time, achieving the maximum values of the average size at 20 min with magnetic field and at 40 min without magnetic field. Larger-sized and tighter agglomerates can be formed in a shorter time by the Lorentz force in magnetic field. As magnetic field was applied, the surface electronegativity of rhodochrosite in emulsion solution was stronger and positively correlated with magnetic field intensity. In addition, due to the higher solubility of oleic acid, the adsorption capacity and net heat of emulsion increased, resulting in a stronger hydrophobicity of rhodochrosite with a shorter hydrophobization time. Interestingly, almost no attraction existed between particles with magnetic field in aqueous solution, while a larger attraction existed without magnetic field in emulsion solution, and the attraction and action distance both increased markedly with increasing magnetic field intensity. However, the magnetic attraction was much smaller than hydrophobic attraction. As a result, agglomeration of rhodochrosite fines could be enhanced by stronger hydrophobic attraction under the synergy effect of magnetic field and oleic-kerosene emulsion. This research will be conducive to in-depth insight into the enhancement mechanisms of rhodochrosite agglomeration and will provide a basis for flotation regulation.