Interaction between fine particles of fluorapatite and phosphoric acid unraveled by surface spectroscopies

Flotation mechanisms of calcareous phosphates ores, and in particular the reaction between phosphoric acid fluorapatite have still to be elucidated. In present work, variations carbonated hydroxyfluorapatite (C-HFAp) contact with various concentrations were studied using ex-situ in-situ techniques, namely Raman Infrared spectroscopy, X-Ray diffraction (XRD) Scanning Electron microscopy (SEM). spectra showed a calcium carbonate peak (CaCO3) (1085 cm−1) at low (between 10−3 10−2 mol.L−1), disappearing higher concentrations. Similarly, kinetic studies that, even if CaCO3 appeared after 2 min reaction, it disappeared 3 min. IR diffractograms seemed display presence (peak 713 cm−1 on spectra), change crystallinity C-HFAp surface increasing (broadening peak). Our results highlight conversion hydroxyfluoroapatite high concentrations, coating mineral which prevents dissolution can impact adsorption collectors. work contributes understanding depression apatite minerals phosphate ores flotation.