Utilization of gellan gum as a novel eco-friendly depressant in the flotation separation of fluorite from barite

Abstract

The relatively similar physicochemical features and floatabilities of fluorite and barite in the flotation process make the separation of these two minerals rather difficult. Exploration and utilization of efficient depressants is vital to improve the flotation separation performance. In this study, gellan gum (GG) was adopted as the depressant in the flotation separation of fluorite and barite with sodium oleate (NaOL) as collector for the first time. The inhibitory impact of gellan gum on the flotation performances of these two minerals was evaluated via flotation tests. The potential inhibiting mechanism of GG was systematically revealed via series of surface analytical measurements. Flotation experiments indicated that GG exhibited strong depressing effect on the barite flotation, whilst it showed little impact on the fluorite flotation. Zeta potential tests and surface wettability analyses demonstrated that GG intensely adhered onto barite and strongly prevented the subsequent NaOL adsorption, while it barely affected the NaOL adsorption onto fluorite. Adsorption capacity measurements confirmed that much higher amount of GG adsorbed onto barite than fluorite. Fourier transform infrared (FTIR) spectroscopy analyses and X-ray photoelectron spectroscopy (XPS) results implied that the quite weak physisorption of GG on the fluorite surface occurred, whereas strong chemical adhesion of GG occurred between GG and barite, which resulted in completely disparate flotation behaviors of these two minerals. As a result, selectively depression of barite flotation and the flotation separation of fluorite from barite were achieved. Therefore, GG can be used as an efficient and eco-friendly depressant to realize the flotation separation of fluorite and barite.