S-[2-(Hydroxyamino)-2-Oxoethyl]-O-Octyl-Dithiocarbonate Ester (EHAOX): Performance and Adsorption Mechanism

This study explores the interfacial interactions between a novel collector, S-[2-(hydroxyamino)-2-oxoethyl]-O-octyl-dithiocarbonate ester (EHAOX), and bastnaesite mineral surfaces during selective flotation. Compared to conventional octylhydroxamic acid (OHA), EHAOX demonstrated superior recovery, achieving an over 40% absolute increase in recovery compared to octylhydroxamic acid (OHA) at the same collector concentration (1 × 10−5 mol/L) and pH 8.0, and selectivity for bastnaesite, attributed to its optimized hydrophobicity (supported by CLogP calculations). Mechanistic studies via zeta potential, UV/vis spectroscopy, and FTIR revealed the formation of a complex composite via chemisorption between EHAOX and Ce3+ sites on the bastnaesite surface, with coordination occurring through the sulfur (N-C(=S)) and oxygen (-C(=O)N-OH) functional groups. This selective adsorption minimized EHAOX’s affinity for calcite, highlighting its potential for tailoring composite mineral separation processes. The findings advance the design of functionalized collectors for rare-earth mineral enrichment, with implications for composite material processing in resource recovery.