Open Collections

Abstract

This study investigates and compares the flotation behavior of three sulfide minerals, boulangerite (Pb₅Sb₄S₁₁), stibnite (Sb₂S₃), and galena (PbS), using a combination of surface characterization and laboratory-scale flotation techniques. The objectives were to evaluate their natural hydrophobicity and floatability, compare their flotation performance, and determine the conditions that optimize boulangerite recovery. Experimental methods included particle size analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), micro-Fourier transform infrared (micro-FTIR) spectroscopy, bubble pick-up tests, high-speed camera imaging, and Hallimond tube tests. The results reveal distinct differences in flotation chemistry and reagent interactions. Galena exhibited the strongest and most consistent response to xanthate collectors, forming stable xanthate products under all tested conditions and achieving high recoveries. Boulangerite showed pronounced adsorption of potassium amyl xanthate (PAX) and methyl isobutyl carbinol (MIBC), with slightly enhanced flotation after lead nitrate activation. In contrast, stibnite required lead nitrate activation to achieve substantial xanthate adsorption and flotation, indicating its weaker baseline reactivity. Micro-FTIR spectra confirmed the presence of characteristic xanthate and hydrocarbon functional groups, while bubble pick-up and Hallimond tube tests supported the observed flotation trends. Boulangerite and stibnite displayed significant natural hydrophobicity while galena was weakly naturally hydrophobic. Across the tested pH range (3–9.5), boulangerite showed limited sensitivity to pH, with slightly better performance under alkaline conditions; galena favored alkaline environments, while stibnite flotation improved under acidic conditions. Particle size variations and limited sample availability were identified as experimental constraints, although reproducibility was maintained. These findings provide micro-scale insights into the similarities and differences in the flotation behavior of boulangerite, stibnite, and galena.