Effect of lead ions treatment on the flotation behavior of lime-depressed pyrite in a butyl xanthate system

[Display omitted] •Flotation recovery of lime-depressed pyrite was improved followed by addition of lead ions.•Lead ions could adsorb onto lime-depressed pyrite surfaces and generated Pb-S and Fe-O-Pb hydrophobic species.•Addition of lead ions increased the adsorption of xanthate species onto lime-depressed pyrite surfaces. Pyrite is often found alongside other sulfide minerals and is typically suppressed by lime during industrial flotation to selectively enrich with other valuable minerals. Given the continuous depletion of mineral resources, recycling these suppressed resources has become necessary. Consequently, the reactivation of lime-depressed pyrite is crucial for its recovery via flotation. This study investigated the lead (Pb) nitrate to activate lime-depressed pyrite. Various analytical techniques, including micro-flotation tests, zeta potential measurements, contact angle measurements, ultraviolet–visible spectrophotometry, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM-EDS) were employed to investigate the activation mechanism of Pb2+ on lime-depressed pyrite. The treatment with Pb2+ resulted in a significant enhancement in the recovery of lime-depressed pyrite flotation, achieving a maximum recovery of 98.33 %. Analysis through zeta potential, XPS, and SEM-EDS revealed that Pb species reacted with lime-depressed pyrite surfaces to form Pb-S and Fe-O-Pb species. This reaction enhanced the active sites and adsorption of collectors on lime-depressed surfaces, consequently increasing the hydrophobicity of the pyrite particles.