Efficient selective flotation separation of talc and molybdenite with a novel molybdenite depressant: Remarkable performance and mechanism

The separation of talc and molybdenite is a challenging and research hotspot in mineral processing. In the work, a nitrous acid ester depressant (M−DEP) was first synthesized and used as a molybdenite depressant for the separation of talc and molybdenite via reverse flotation. Flotation tests of single-mineral and multi-mineral samples were carried out to evaluate the effect of M−DEP on the flotation behavior of molybdenite and talc. Zeta potential, X-ray photoelectron spectroscopy, and Fourier Transform Infrared Spectroscopy were used to analyze the selective depression mechanism of M−DEP on molybdenite and talc. Furthermore, the adsorption behavior of M−DEP on specific crystallographic planes of minerals has been studied by contact angle, atomic force microscope, and DFT calculation. Flotation experiment results indicated that M−DEP had excellent selective depression on molybdenite in the pH range of 5 to 10. The results of mechanism analysis showed that M−DEP could be adsorbed on molybdenite “basal” surface by hydrophobic interaction, and on molybdenite “edge” surface by chemical interaction, while could not be adsorbed on the surface of talc due to electrostatic repulsion. M−DEP enlarged the surface floatability difference between talc and molybdenite and promoted the efficient separation of talc and molybdenite via reverse flotation.