Removal of dolomite and potassium feldspar from apatite using simultaneous flotation with a mixed cationic-anionic collector

This study aims to investigate the effect of a cationic-anionic mixed collector (dodecyltrimethyl ammonium bromide/sodium oleate (DTAB/NaOL) on the selective separation of apatite, dolomite, and potassium feldspar. Herein, several experimental methods, including flotation experiments, zeta-potential detection, microcalorimetry detection, XPS analysis and FTIR measurements, were used. The flotation tests showed that dolomite and potassium feldspar can be successfully removed from apatite simultaneously when the molar ratio of DTAB to NaOL was 2:1 with pH 4.5. Zeta-potential and Microcalorimetry detection suggested that NaOL and DTAB were adsorbed on the surface of dolomite and potassium feldspar respectively, and part of NaOL and DTAB formed co-adsorption on the surface of potassium feldspar to enhance the floatability of potassium feldspar. The XPS and FTIR spectra analysis demonstrated that the cationic collector, DTAB, was first adsorbed on the surface of potassium feldspar through electrostatic attraction in the DTAB/NaOL mixture system. Subsequently, the anionic NaOL collector and cationic DTAB collector form an electron neutralisation complex, thereby resulting in co-adsorption on the surface of potassium feldspar. NaOL was chemically reacted and adsorbed on dolomite surface, but almost no collector was adsorbed on apatite surface. Finally, the adsorption models of different collectors on mineral surface were obtained.