Selective flotation separation of magnesite from quartz by palmitoyl trimethylammonium chloride

Abstract

To achieve efficient separation of magnesite from quartz, it is crucial to develop highly selective collector. In this work, for the size range of samples was −74 + 35 μm (d80 = 70.96 μm), the effect of palmitoyl trimethylammonium chloride (PTAC) on the flotation separation of magnesite and quartz was studied for the first time. Micro-flotation test results indicated that PTAC had a selective-collection influence on quartz and that magnesite separation from quartz could be accomplished at pH 7.0 and 30 mg/L PTAC. Zeta-potential and contact-angle tests indicated that PTAC could selectively increased the isoelectric point and hydrophobicity of quartz surface, but had no such effect on magnesite. Fourier-transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM) coupled with energy dispersion spectroscopy (EDS) measurements revealed that PTAC was mainly adsorbed on the surface of quartz, and selective adsorption of PTAC onto quartz surface could be attributed to electrostatic attraction and hydrogen bonds. Molecular dynamics simulation (MDS) further revealed the high selectivity of PTAC adsorption on quartz, through the peak position of PTAC molecular number density, water diffusion coefficient and the interaction energy between PTAC and the minerals. Finally, extended Derjaguin-Landau-Verwey-Overbeek theoretical calculation showed that the addition of 30 mg/L PTAC could change the total force VTED between magnesite and quartz from attraction to repulsion, which was conducive to the separation between them.