Effect of kerosene emulsion in MgCl₂ solution on the kinetics of bubble interactions with molybdenite and chalcopyrite

The formation of stable bubble-particle aggregates is essential to the froth flotation process. To form such aggregates, bubbles and particles must collide, the intervening liquid film must be drained below its critical rupture thickness, and three-phase contact (TPC) formation must occur. A good understanding of the interaction mechanism between bubbles and particles during collision and attachment is important. We herein investigated the effects of emulsified kerosene in a 0.01 M MgCl₂ solution (a model seawater component) on bubble interactions with pure molybdenite (MoS₂) and chalcopyrite (CuFeS₂) surfaces. In 0.01 M MgCl₂ at pH 6 and 11, kerosene retarded the bubble surface mobility and reduced the bubble rise velocity. In the presence of kerosene at pH 6, the TPC formed more rapidly on both mineral surfaces. This was due to the increase in surface hydrophobicity caused by kerosene. In addition, TPC formation was more rapid on the molybdenite surface than on the chalcopyrite surface due to the effect of the adsorbed kerosene and the low surface homogeneity of molybdenite. Finally, floatability tests demonstrated that the separation of molybdenite and chalcopyrite should be possible by adding emulsified kerosene in a 0.01 M MgCl₂ solution at pH 9.