Understanding adsorption mechanism of a novel "Y" structure carboxylate-hydroxamate surfactant towards rhodochrosite.

[Display omitted] • 2-Decanoylamino-4-hydroxycarbamoyl-butyric acid (DHBA) is designed. • "Y" structure surfactant DHBA is used as rhodochrosite flotation collector. • DHBA exhibits excellent collecting ability to rhodochrosite at a low dosage. • DHBA achieved a selective flotation separation of rhodochrosite from quartz at pH 7. • Both carboxyl and hydroxamic groups of DHBA chemisorbed on rhodochrosite surface. High consumption and low selectivity of traditional collectors limit the efficient flotation recovery of rhodochrosite particles from finely disseminated complex ores. Herein, a novel "Y" structure multi-functional surfactant, 2-decanoylamino-4-hydroxycarbamoyl-butyric acid (DHBA) was developed for flotation recovery of rhodochrosite. The micro-flotation results showed that DHBA exhibited an excellent collecting ability for rhodochrosite than common collector octanohydroxamic acid (OHA) (the recovery reached 85.7% for 7 × 10–5 mol·L–1 DHBA, while only 27.9% for OHA). Meanwhile, DHBA can selectively separated rhodochrosite from quartz at neutral pH and low collector dosages. The experimental analysis combined with the density functional theory calculations revealed that DHBA was lattice matched to the rhodochrosite via the oxygen atoms of carboxyl and hydroxamate groups chelating with two Mn atoms, conferring strong adsorption affinity of DHBA. In addition, intermolecular hydrogen bonds coexist through the amide groups, promoting the collectors' self-assembly on the rhodochrosite surface, improving surface hydrophobicity. This research provides a feasible collector design protocol for the separation and enrichment of manganese carbonate ore. [ABSTRACT FROM AUTHOR]