Enhanced flotation separation of spodumene and albite via selective adsorption of N-hydroxy-9-octadecenamide on the mineral surfaces

Abstract

Spodumene (LiAl(SiO3)2) is an important Li-bearing mineral from which Li is extracted economically. Flotation is an important method for separating spodumene from its associated gangue minerals such as albite. Oleic acid is a traditional collector utilized in the flotation separation of spodumene/albite; however, it has limited selectivity. To address this, N-hydroxy-9-octadecenamide (N-OH-9-ODA) is developed by transforming the carboxyl group, the polar group of oleic acid, into the N-hydroxy amide group. A comparative investigation of N-OH-9-ODA and oleic acid in the flotation separation of spodumene/albite is conducted through flotation experiments. The findings of the flotation experiments indicate that N-OH-9-ODA exhibits better selectivity and stronger collecting ability than oleic acid. N-OH-9-ODA has a stronger affinity for spodumene than albite, which is reflected by a more significant shift in the zeta potential of spodumene particles compared to albite particles caused by the additions of N-OH-9-ODA. The flotation experiments also show that the prior addition of Ca2+ ions can enhance the ability of N-OH-9-ODA to collect spodumene particles. The activation of Ca2+ ions for the N-OH-9-ODA flotation of spodumene is due to the stronger reactivity of Ca2+ ions adsorbed on spodumene surface for the N-OH-9-ODA adsorption compared to Al3+ ions of pure spodumene surface, which is demonstrated by a higher adsorption energy of N-OH-9-ODA on the Ca2+-activated spodumene surface than that on pure spodumene surface.