Selective adsorption of hydrolyzed polymaleic anhydride as an eco-friendly depressant on galena during the flotation of molybdenite: Experimental and DFT study

Achieving efficient and sustainable separation of molybdenite from galena remains a significant challenge in mineral processing. This study evaluated the effectiveness of hydrolyzed polymaleic anhydride (HPMA) as a selective depressant for galena in a kerosene flotation system, focusing particularly on its impact on the separation efficiency between molybdenite and galena. Micro-flotation experiments showed that at pH 8, HPMA effectively suppressed galena flotation while maintaining molybdenite recovery above 95 %. Mixed mineral flotation tests further validated the exceptional performance of HPMA, achieving high-efficiency separation with a Mo recovery rate exceeding 95 % in the froth product while effectively suppressing the Pb recovery rate to 5.38 %. Zeta potential and contact angle analyses revealed stronger HPMA adsorption on galena than on molybdenite, increasing galena's hydrophilicity and preventing collector attachment. FT-IR, XPS and DFT analyses confirmed the exclusive formation of chemical bonds between HPMA's carboxyl groups and galena's Pb sites, leading to stable surface complexes that amplify the wettability differences between the minerals. These mechanisms may represent the key factors responsible for the effective separation of the two minerals, establishing HPMA as a promising eco-friendly reagent with considerable industrial application potential.