Surface-specific adsorption of a novel collector in bastnaesite-barite flotation: Insights from spectroscopy and DFT calculations

The surface characteristics of bastnaesite and barite are highly similar, leading to comparable reagent interactions during flotation processes. Conventional collectors often demonstrate limited selectivity and suboptimal collection efficiency, which negatively impact flotation outcomes. Effective mineral separation requires highly selective and efficient collectors. This study presents the synthesis and initial application of lauryl hydroxamic acid (LHA) as a new collector for the flotation of bastnaesite. LHA exhibited remarkable selectivity and collecting efficiency in the flotation separation of bastnaesite from barite. The synergistic application of LHA and carboxymethyl cellulose (CMC) as depressants enabled effective separation. This resulted in a recovery difference of up to 66.5 % between the two minerals. Spectroscopic analysis revealed that LHA interacts with Ce sites on bastnaesite surfaces through N and O atoms in its hydroxamate groups. Pre-adsorption of CMC was found to prevent LHA adsorption on barite without affecting its adsorption on bastnaesite. LHA adsorbs through the synergistic effect of electrostatic interaction and chemisorption. Comparative analysis indicated that LHA’s hydroxamate group possesses lower non-bonded tension than traditional octyl hydroxamic acid (OHA), enhancing its chelate-forming capability. Density Functional Theory calculations identified hydroxamate groups as LHA’s primary active sites, with O and N atoms playing critical roles. This research systematically investigates the potential of LHA for bastnaesite-barite separation and elucidates its adsorption mechanism. The findings not only advance theoretical understanding of selective flotation control but also provide molecular design guidelines for novel collector development.