Enhanced flotation separation of barite and fluorite using tetrasodium iminodisuccinate (IDS) as a biodegradable fluorite depressant: Experiments and DFT calculations

With the increasing of application fields and market demand of barite and fluorite, the research of flotation separation of barite and fluorite has attracted much attention. In this work, a novel biodegradable fluorite depressant, tetrasodium iminodisuccinate (IDS) was developed for the flotation separation of barite and fluorite in sodium dodecyl sulfonate (SDSN) system, and its interaction mechanism were revealed. The micro-flotation results proved IDS had a strong depressant on fluorite at pH 6-11. Under the best conditions (pH 8, IDS 30 mg/L, SDSN 1 x 10-4 mol/L), the BaSO4 grade and recovery in the concentrate reached 90.15 % and 92.00 %, and the CaF2 grade and recovery in the tailing reached 89.77 % and 95.32 %, which indicated that IDS could achieve the separation of barite and fluorite. Zeta potential, contact angle, Fourier Transform Infrared Spectrometer (FTIR), X-ray Photoelectron Spectroscopy (XPS) and Density Functional Theory (DFT) calculation indicated that IDS was chemisorbed on the fluorite, forming a bidentate binuclear stable adsorption configuration through the coordination of O with Ca site of fluorite, while a weak physical adsorption occurred between IDS and barite. Furthermore, the pre-adsorption of IDS hindered the binding between SDSN and fluorite, while the effect on barite was negligible. Therefore, IDS as a biodegradable and high-selectivity depressant, has potential value in the separation of barite and fluorite.