A corn Stalk-Derived carboxymethyl cellulose for efficient Molybdenite-Talc flotation separation by weakening hydrophobic attraction

A corn stalk-derived carboxymethyl cellulose (CMCQ) was successfully synthesized. • CMCQ achieved efficient flotation separation of molybdenite from talc. • CMCQ selectively adsorbed onto the talc surface and reduced its hydrophobicity. • CMCQ weakened basal-plane hydrophobic attraction for molybdenite-talc separation. Molybdenite (MoS 2 ) is a key mineral resource for molybdenum extraction, but its natural floatability is similar to that of the associated gangue mineral talc (Mg 3 Si 4 O 10 (OH)), making effective separation difficult. Conventional polymeric depressants, due to their high viscosity, tend to adsorb non‑selectively on both molybdenite and talc surfaces, resulting in a low grade of molybdenum. Hence, this study synthesized a corn stalk‑derived carboxymethyl cellulose (CMCQ) from low‑viscosity agricultural waste (corn stalk) and applied it for the first time to the flotation separation of molybdenite from talc. Through single-mineral flotation tests, adsorption analysis, contact angle measurements, Zeta potential measurements, Fourier-transform infrared spectroscopy (FTIR), in situ optical microscope observation, and Extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory calculations, the depression performance and selective mechanism of CMCQ were systematically evaluated. The results show that CMCQ strongly depresses talc, with a talc recovery as low as 10.2% at a concentration of 100 mg/L, while its depression on molybdenite remains weak. Compared with commercial carboxymethyl cellulose (CMC), CMCQ reduces talc recovery from over 60.0% to 10.2% at the same concentration, demonstrating a significantly improved depressing effect. Mechanistic studies reveal that CMCQ selectively adsorbs onto the talc surface, reduces its hydrophobicity, and weakens the hydrophobic attraction between the basal planes of molybdenite and talc. As a result, particle adhesion is largely eliminated, leading to efficient selective separation. This study not only facilitates the high-value utilization of corn straw but also provides a novel, efficient depressant for the flotation separation of molybdenite from talc, which is of great significance for promoting sustainable mineral processing technology. A Corn Stalk-Derived Carboxymethyl Cellulose for Efficient Molybdenite-Talc Flotation Separation by Weakening Hydrophobic Attraction. Download: Download high-res image (165KB) Download: Download full-size image