Selective separation of iron-bearing silicate minerals from hematite via a novel collector: surface interaction mechanistic investigation

This study evaluates α-bromolauric acid (α-BLA) as a novel collector for the reverse flotation separation of hematite from iron-bearing silicate minerals (hornblende and aegirine). Flotation performance and underlying mechanisms were systematically analyzed through micro-flotation tests, performance quantification, contact angle measurements, zeta potential analysis, FTIR, and XPS spectroscopy. Performance quantification confirmed that α-BLA exhibits “Top” collecting ability but limited selectivity, necessitating starch as a depressant. Under optimal conditions (pH = 11, α-BLA = 57.2 mg/L, CaCl₂ = 25.75 mg/L), total iron grade and recovery reached 63.08 % and 77.64 %, respectively, while SiO₂ content decreased to 5.40 %. The iron site density on mineral surfaces is critical for reagent adsorption, as both α-BLA and starch bind via these sites. Even after starch treatment, α-BLA selectively adsorbs onto hornblende and aegirine, effectively regulating flotation interfaces. At the bubble–mineral interface, hydrophobic attraction, hydrophilic repulsion, and electrostatic interactions govern bubble attachment, enabling efficient mineral separation. This study introduces α-BLA as a promising industrial collector for iron ore reverse flotation and offers mechanistic insights for developing high-performance flotation reagents.